Video Atlas of Neuroendovascular Procedures 1684201187, 9781684201181

Table of contents :
Video Atlas of Neuroendovascular Procedures
MedOne Information
Title Page
Copyright
Dedication
Contents
Video Contents
Foreword
Preface
Acknowledgments
Contributors
Part I Vascular Access
1 Femoral Artery Access and Closure
2 Femoral Vein Access
3 Brachial Artery Access
4 Radial Artery Access
5 Direct Carotid Artery Access
Part II Diagnostic Procedures
6 Diagnostic Cerebral Angiography
7 Diagnostic Spinal Angiography
8 Diagnostic Cerebral Venography
9 Balloon Test Occlusion
10 Inferior Petrous Sinus Sampling
Part III Extracranial Vessel Angioplasty/Stenting
11 Carotid Artery Stenting with Distal Protection
12 Carotid Artery Stenting with Proximal Protection (Flow Arrest)
13 Carotid Artery Stenting under Flow Reversal
14 Angioplasty for In-Stent Restenosis or Recurrent Stenosis
15 Vertebral Artery Stenting
16 Venous Sinus Stenting
Part IV Acute Stroke Procedures
17 Anterior Circulation Mechanical Thrombectomy (ADAPT)
18 Anterior Circulation Mechanical Thrombectomy with Stent Retriever
19 Posterior Circulation Mechanical Thrombectomy
20 Mechanical Thrombectomy with Intracranial Stenting/Angioplasty
21 Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty
22 Intracranial Atherosclerotic Disease-Intracranial Angioplasty
Part V Intracranial Aneurysms
23 Primary Aneurysm Coiling
24 Balloon-Assisted Coiling
25 Stent-Assisted Coiling
26 Flow Diversion Treatment of Intracranial Aneurysms
27 Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)
28 Novel Aneurysm Neck Reconstruction Devices
29 Aneurysm Embolization with Liquid Embolic Agents
30 Endovascular Vasospasm Treatment
Part VI Brain Arteriovenous Malformations and Fistulas
31 Arteriovenous Malformation Embolization with Onyx
32 Arteriovenous Embolization with N-butyl-2-cyanoacrylate
33 Endovascular Embolization of Dural Arteriovenous Fistulas
34 Spinal Arteriovenous Fistula and Malformation Embolization
35 Carotid-Cavernous Fistula Embolization
Part VII Head and Neck Embolization
36 Endovascular Treatment of Epistaxis
37 Central Nervous System Tumors
38 Embolization of Carotid Body Tumors
39 Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction
Part VIII Endovascular Complications and Management
40 Complications of Neuroendovascular Interventions
Index
Additional MedOne Information

Citation preview

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Video Atlas of Neuroendovascular Procedures

Leonardo Rangel-Castilla, MD Assistant Professor Department of Neurosurgery and Radiology Mayo Clinic Rochester, Minnesota, USA Consultant Neurosurgeon Private Practice San Luis Potosi, SLP, Mexico Adnan H. Siddiqui, MD, PhD, FACS, FAHA, FAANS Professor and Vice Chair Director Neuroendovascular Fellowship Program Department of Neurosurgery and Radiology State University of New York Buffalo, New York, USA Elad I. Levy, MD, MBA, FACS, FAHA Professor and Chair Department of Neurosurgery and Radiology State University of New York Director of Interventional Stroke Services Kaleida Health Network Buffalo, New York, USA

1065 illustrations

Thieme New York • Stuttgart • Delhi • Rio de Janeiro

Contributors Giuseppe Lanzino, MD Professor of Neurological Surgery and Radiology Mayo Clinic Rochester, Minnesota, USA L. Nelson Hopkins, MD, FACS SUNY Distinguished Professor Founder, Gates Vascular and Jacobs Institute CSO, Jacobs Institute UB Neurosurgery SUNY Buffalo Buffalo, New York, USA Jason M. Davies, MD, PhD Assistant Professor Cerebrovascular and Skullbase Neurosurgery Departments of Neurosurgery and Biomedical Informatics Director of Cerebrovascular Microsurgery Director of Endoscopy, Kaleida Health Research Director, Jacobs Institute State University of New York, Buffalo Buffalo, New York, USA

Library of Congress Cataloging-in-Publication Data Names: Rangel-Castilla, Leonardo, author. | Siddiqui, Adnan H., author. | Levy, Elad I., author. Title: Video atlas of neuroendovascular procedures / Leonardo Rangel-Castilla, Adnan H. Siddiqui, Elad I. Levy ; contributors, Giuseppe Lanzino, L. Nelson Hopkins, Jason M. Davies. Description: New York : Thieme, [2020] | Includes bibliographical references and index. | Summary: “Unlike traditional textbooks that detail natural history, physiology, and morphology, Video Atlas of Neuroendovascular Procedures presents basic and complex neuroendovascular procedures and cases with concise text and videos. Renowned neuroendovascular surgeons Leonardo Rangel-Castilla, Adnan Siddiqui, Elad Levy, and an impressive group of contributors have compiled the quintessential neuroendovascular resource. Organized into eight major subtopic sections, this superb video atlas covers a full spectrum of endovascular approaches to diagnose and treat intra- and extracranial neurovascular disease. The book starts with a section on vascular access and concludes with endovascular complications and management. Forty chapters includes succinct summaries, scientific procedural evidence, the rationale for endovascular intervention, anatomy, required medications, device selection, avoiding complications, and managing potential problems that can arise during procedures. The image-rich clinical cases feature insightful firsthand knowledge and pearls”-- Provided by publisher. Identifiers: LCCN 2019027164 | ISBN 9781684201181 (hardback) | ISBN 9781684201198 (eISBN) Subjects: MESH: Endovascular Procedures--methods | Neurosurgical Procedures--methods | Cerebrovascular Disorders--surgery | Cerebrovascular Disorders--diagnosis | Case Reports | Atlas Classification: LCC RD598.5 | NLM WL 17 | DDC 617.4/130222-dc23 LC record available at https://lccn.loc.gov/2019027164

Important note: Medicine is an ever-changing science undergoing continual development. Research and clinical experience are con- tinually expanding our knowledge, in particular our knowledge of proper treatment and drug therapy. Insofar as this book mentions any dosage or application, readers may rest assured that the authors, editors, and publishers have made every effort to ensure that such references are in accordance with the state of knowledge at the time of production of the book. Nevertheless, this does not involve, imply, or express any guarantee or responsibility on the part of the publishers in respect to any dosage instructions and forms of applications stated in the book. Every user is requested to examine carefully the manufacturers’ leaflets accompanying each drug and to check, if necessary in consultation with a physician or specialist, whether the dosage schedules mentioned therein or the contraindications stated by the manufacturers differ from the statements made in the present book. Such examination is particularly important with drugs that are either rarely used or have been newly released on the market. Every dosage schedule or every form of application used is entirely at the user’s own risk and responsibility. The authors and publishers request every user to report to the publishers any discrepancies or inaccuracies noticed. If errors in this work are found after publication, errata will be posted at www.thieme. com on the product description page. Some of the product names, patents, and registered designs referred to in this book are in fact registered trademarks or proprietary names even though specific reference to this fact is not always made in the text. Therefore, the appearance of a name without designation as proprietary is not to be construed as a representation by the publisher that it is in the public domain.

© 2020 Thieme Medical Publishers, Inc. Thieme Publishers New York 333 Seventh Avenue, New York, NY 10001 USA +1 800 782 3488, [email protected] Thieme Publishers Stuttgart Rüdigerstrasse 14, 70469 Stuttgart, Germany +49 [0]711 8931 421, [email protected] Thieme Publishers Delhi A-12, Second Floor, Sector-2, Noida-201301 Uttar Pradesh, India +91 120 45 566 00, [email protected] Thieme Publishers Rio de Janeiro, Thieme Publicações Ltda. Edifício Rodolpho de Paoli, 25º̲ andar Av. Nilo Peçanha, 50 – Sala 2508 Rio de Janeiro 20020-906, Brasil +55 21 3172 2297 Cover design: Jennifer Pryll Typesetting by Adept Content Solutions Printed in the United States of America by King Printing ISBN 978-1-68420-118-1 Also available as an e-book: eISBN 978-1-68420-119-8

This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow limits set by copyright legislation without the publisher’s consent is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

I dedicate this book to my son Leonardo, the love of my life and the best thing that ever happened to us; and to my wife, Andrea, for her unconditional care, tolerance, and patience, during good and bad moments. Leonardo Rangel-Castilla

This book is dedicated to the unyielding support, generosity, and love from my caring and benevolent wife, Cindy, and three children, Bennett, Hannon, and Lauren. And to my parents, who taught me by example that passion, grit, and sacrifice are the key components to everything worth accomplishing. Elad I. Levy

I dedicate this work to the fellows who have come to Buffalo for their endovascular training. It is their dedication and passion which is the fuel that has powered this work. It is their energy and enthusiasm which is reflected in these cases and their intuition and curiosity which has been the driving force for academic progress— the hallmark of our program at Buffalo. To all the women and men graduates of the Buffalo program—thank you! Adnan H. Siddiqui

Contents Video Contents.....................................................................................................................................................................x Foreword.............................................................................................................................................................................xv Preface................................................................................................................................................................................ xvi Acknowledgments.......................................................................................................................................................... xvii Contributors...................................................................................................................................................................xviii Part I  Vascular Access......................................................................................................................................................1 1 Femoral Artery Access and Closure...............................................................................................................................3 Gary B. Rajah and Leonardo Rangel-Castilla 2 Femoral Vein Access........................................................................................................................................................ 17 Gary B. Rajah and Leonardo Rangel-Castilla 3 Brachial Artery Access.................................................................................................................................................... 20 Jason M. Davies 4 Radial Artery Access........................................................................................................................................................ 23 Jason M. Davies 5 Direct Carotid Artery Access......................................................................................................................................... 26 Jason M. Davies Part II  Diagnostic Procedures..................................................................................................................................... 31 6 Diagnostic Cerebral Angiography................................................................................................................................ 33 Gary B. Rajah and Leonardo Rangel-Castilla 7 Diagnostic Spinal Angiography.................................................................................................................................... 41 Gary B. Rajah and Leonardo Rangel-Castilla 8 Diagnostic Cerebral Venography................................................................................................................................. 45 Jason M. Davies 9 Balloon Test Occlusion.................................................................................................................................................... 48 Jason M. Davies and Leonardo Rangel-Castilla 10 Inferior Petrous Sinus Sampling.................................................................................................................................. 54 Enrico Giordan, Giuseppe Lanzino, and Leonardo Rangel-Castilla Part III  Extracranial Vessel Angioplasty/Stenting.................................................................................................. 59 11 Carotid Artery Stenting with Distal Protection....................................................................................................... 61 Gary B. Rajah and Leonardo Rangel-Castilla 12 Carotid Artery Stenting with Proximal Protection (Flow Arrest)....................................................................... 81 Gary B. Rajah and Leonardo Rangel-Castilla 13 Carotid Artery Stenting under Flow Reversal.......................................................................................................... 97 Jason M. Davies 14 Angioplasty for In-Stent Restenosis or Recurrent Stenosis................................................................................102 Gary B. Rajah and Leonardo Rangel-Castilla 15 Vertebral Artery Stenting............................................................................................................................................110 Jason M. Davies

vii

Contents 16 Venous Sinus Stenting..................................................................................................................................................114 Jason M. Davies and Leonardo Rangel-Castilla Part IV  Acute Stroke Procedures.............................................................................................................................. 123 17 Anterior Circulation Mechanical Thrombectomy (ADAPT)................................................................................125 Gary B. Rajah and Leonardo Rangel-Castilla 18 Anterior Circulation Mechanical Thrombectomy with Stent Retriever.........................................................133 Gary B. Rajah and Leonardo Rangel-Castilla 19 Posterior Circulation Mechanical Thrombectomy...............................................................................................169 Jason M. Davies, Elad I. Levy, and Adnan H. Siddiqui 20 Mechanical Thrombectomy with Intracranial Stenting/Angioplasty.............................................................179 Kunal Vakharia, Muhammad Waqas, Adnan H. Siddiqui, and Elad I. Levy 21 Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty.....................188 Gary B. Rajah and Leonardo Rangel-Castilla 22 Intracranial Atherosclerotic Disease—Intracranial Angioplasty.......................................................................198 Kunal Vakharia, Elad I. Levy, and Adnan H. Siddiqui Part V  Intracranial Aneurysms................................................................................................................................ 209 23 Primary Aneurysm Coiling.........................................................................................................................................211 Kunal Vakharia, Adnan H. Siddiqui, and Elad I. Levy 24 Balloon-Assisted Coiling..............................................................................................................................................246 Leonardo Rangel-Castilla and Giuseppe Lanzino 25 Stent-Assisted Coiling...................................................................................................................................................257 Stephan A. Munich, Elad I. Levy, and Adnan H. Siddiqui 26 Flow Diversion Treatment of Intracranial Aneurysms........................................................................................285 Gary B. Rajah, Giuseppe Lanzino, and Leonardo Rangel-Castilla 27 Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)......................................................................320 Gary B. Rajah, Leonardo Rangel-Castilla, Willem Jan van Rooij, and Jo P. Peluso 28 Novel Aneurysm Neck Reconstruction Devices.....................................................................................................331 Stephan A. Munich and Leonardo Rangel-Castilla 29 Aneurysm Embolization with Liquid Embolic Agents........................................................................................349 Gary B. Rajah and Leonardo Rangel-Castilla 30 Endovascular Vasospasm Treatment........................................................................................................................363 Gary B. Rajah and Leonardo Rangel-Castilla Part VI  Brain Arteriovenous Malformations and Fistulas................................................................................. 369 31 Arteriovenous Malformation Embolization with Onyx......................................................................................371 Gary B. Rajah and Leonardo Rangel-Castilla 32 Arteriovenous Embolization with N-butyl-2-cyanoacrylate.............................................................................395 Kunal Vakharia, Muhammad Waqas, Michael K. Tso, Adnan H. Siddiqui, and Elad I. Levy 33 Endovascular Embolization of Dural Arteriovenous Fistulas............................................................................403 Enrico Giordan, Giuseppe Lanzino, and Leonardo Rangel-Castilla 34 Spinal Arteriovenous Fistula and Malformation Embolization........................................................................417 Kunal Vakharia, Muhammad Waqas, Elad I. Levy, and Adnan H. Siddiqui

viii

Contents 35 Carotid-Cavernous Fistula Embolization................................................................................................................428 Stephan A. Munich, Giuseppe Lanzino, and Leonardo Rangel Castilla Part VII  Head and Neck Embolization.................................................................................................................... 437 36 Endovascular Treatment of Epistaxis.......................................................................................................................439 Gary B. Rajah and Leonardo Rangel-Castilla 37 Central Nervous System Tumors...............................................................................................................................447 Kunal Vakharia, Muhammad Waqas, Elad I. Levy, and Adnan H. Siddiqui 38 Embolization of Carotid Body Tumors.....................................................................................................................459 Kunal Vakharia, Muhammad Waqas, Alexander R. Neary, Adnan H. Siddiqui, and Elad I. Levy 39 Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction...............................................................464 Lorenzo Rinaldo, Giuseppe Lanzino, and Leonardo Rangel-Castilla Part VIII  Endovascular Complications and Management.................................................................................. 471 40 Complications of Neuroendovascular Interventions...........................................................................................473 Jason M. Davies, Hussain Shallwani, and Leonardo Rangel-Castilla Index........................................................................................................................................................................... 514

ix

Video Contents Video 1.1  Femoral artery access I.......................................................................................................................................5

x

Video 1.2 

Femoral artery access II.....................................................................................................................................7

Video 1.3 

Pediatric femoral artery access.......................................................................................................................9

Video 1.4 

Percutaneous closure device (AngioSeal).................................................................................................. 11

Video 1.5 

Percutaneous closure device (Mynx) I....................................................................................................... 13

Video 1.6 

Percutaneous closure device (Mynx) II...................................................................................................... 15

Video 2.1 

Femoral vein access......................................................................................................................................... 18

Video 3.1 

Brachial artery access..................................................................................................................................... 21

Video 4.1 

Radial artery access......................................................................................................................................... 24

Video 5.1 

Direct carotid artery access........................................................................................................................... 27

Video 6.1 

Diagnostic cerebral angiography (simple curve catheter).................................................................... 35

Video 6.2 

Diagnostic cerebral angiography (complex curve catheter)................................................................ 38

Video 6.3 

Pediatric diagnostic cerebral angiography (simple curve catheter).................................................. 39

Video 7.1 

Diagnostic spinal angiography (Cobra catheter)..................................................................................... 44

Video 8.1 

Diagnostic cerebral venography.................................................................................................................. 47

Video 9.1 

Balloon test occlusion (anterior circulation)........................................................................................... 50

Video 9.2 

Balloon test occlusion (posterior circulation).......................................................................................... 52

Video 10.1 

Petrosal sinus sampling............................................................................................................................... 57

Video 11.1 

Internal carotid artery stenting angioplasty assessed with intravascular ultrasound.............. 65

Video 11.2 

Carotid artery stenting angioplasty using a mesh-covered stent (Scaffold trial)........................ 68

Video 11.3 

Carotid artery stenting and angioplasty for recurrent stenosis after endarterectomy I........... 71

Video 11.4 

Carotid artery stenting and angioplasty for recurrent stenosis after endarterectomy II......... 74

Video 11.5 

Rescue carotid artery stenting after carotid endarterectomy complication................................ 77

Video 11.6 

Brachial artery approach for carotid artery stenting and angioplasty........................................... 80

Video 12.1 

Flow limiting intraluminal carotid thrombus managed with carotid artery stenting— dual protection............................................................................................................................................... 85

Video 12.2 

Carotid artery stenting for critical carotid artery stenosis using dual balloon catheter........... 89

Video 12.3 

Flow arrest carotid artery stenting for near occlusion carotid artery stenosis I......................... 92

Video 12.4 

Flow arrest carotid artery stenting for near occlusion carotid artery stenosis II........................ 96

Video Contents Video 13.1 

Flow reversal carotid artery stenting for tandem stenosis—Enroute Stent System..................101

Video 14.1 

Carotid artery in-stent stenosis treated with balloon angioplasty................................................105

Video 14.2 

Recurrent carotid artery in-stent stenosis treated balloon angioplasty (drug-eluting balloon)................................................................................................................................108

Video 15.1 

Vertebral artery ostial stenosis treated with stenting and dual balloon angioplasty..............112

Video 16.1 

Left transverse sinus stenting for sinus stenosis................................................................................116

Video 16.2 

Right transverse sinus stenting for sinus stenosis.............................................................................119

Video 17.1 

ADAPT mechanical thrombectomy for acute MCA occlusion I.......................................................128

Video 17.2 

ADAPT mechanical thrombectomy for acute MCA occlusion II......................................................131

Video 18.1 

SOLUMBRA mechanical thrombectomy for acute MCA occlusion.................................................136

Video 18.2 

SOLUMBRA mechanical thrombectomy for acute ICA occlusion...................................................140

Video 18.3 

Direct aspiration and SOLUMBRA mechanical thrombectomy for acute ICA occlusion..........143

Video 18.4 

Balloon guide catheter and SOLUMBRA mechanical thrombectomy for acute ICA occlusion.....................................................................................................................................145

Video 18.5 

Direct carotid artery access for acute MCA occlusion mechanical thrombectomy...................149

Video 18.6 

SOLUMBRA mechanical thrombectomy and submaximal angioplasty for acute MCA occlusion...................................................................................................................................153

Video 18.7 

Multiple parallel glidewire (Zigiwire) for difficult intracranial access during stroke intervention.....................................................................................................................................156

Video 18.8 

Balloon guide catheter and Embotrap mechanical thrombectomy for acute MCA occlusion...................................................................................................................................159

Video 18.9 

Mechanical thrombectomy for acute azygous anterior cerebral artery occlusion...................161

Video 18.10 

Solitaire platinum SOLUMBRA mechanical thrombectomy for acute MCA occlusion...........164

Video 18.11 

Balloon guide catheter and SOLUMBRA mechanical thrombectomy for acute MCA (M2) occlusion......................................................................................................................167

Video 19.1 

Mechanical thrombectomy for acute basilar artery occlusion.......................................................172

Video 19.2 

Submaximal angioplasty for acute basilar artery occlusion...........................................................175

Video 19.3 

Mechanical thrombectomy for acute posterior cerebral artery occlusion..................................178

Video 20.1 

Stenting revascularization of subacute internal carotid artery dissection/ occlusion............183

Video 20.2 

Intracranial stenting for recurrent symptomatic intracranial stenosis.......................................186

Video 21.1 

Endovascular treatment of acute tandem MCA and cervical ICA occlusion I.............................192

Video 21.2 

Endovascular treatment of acute tandem MCA and cervical ICA occlusion II............................196

Video 22.1 

Submaximal angioplasty for symptomatic intracranial stenosis I................................................201

Video 22.2 

Submaximal angioplasty for symptomatic intracranial stenosis II...............................................204

Video 22.3 

Submaximal angioplasty for symptomatic intracranial stenosis III.............................................207

xi

Video Contents

xii

Video 23.1 

Coil embolization of cavernous ICA aneurysm...................................................................................214

Video 23.2 

Triaxial system for coil embolization of ICA terminus aneurysm..................................................217

Video 23.3 

Coil embolization of ruptured ACA aneurysm....................................................................................220

Video 23.4 

Coil embolization of an ACoA aneurysm I............................................................................................223

Video 23.5 

Coil embolization of an ACoA aneurysm II...........................................................................................226

Video 23.6 

Coil embolization of a ruptured PCoA aneurysm and complex aortic arch................................230

Video 23.7 

Coil embolization of multiple intracranial aneurysms.....................................................................233

Video 23.8 

Coil embolization of a PICA aneurysm..................................................................................................235

Video 23.9 

Coil embolization of a recurrent PICA aneurysm...............................................................................238

Video 23.10 

Coil embolization of a basilar artery aneurysm...............................................................................242

Video 23.11 

Coil embolization of a dissecting distal anterior cerebral artery aneu­r ysm............................244

Video 24.1 

Balloon-assisted coiling of a ruptured ACoA aneurysm I.................................................................249

Video 24.2 

Balloon-assisted coiling of a ruptured MCA aneurysm.....................................................................253

Video 24.3 

Balloon-assisted coiling of a ruptured ACoA aneurysm II................................................................256

Video 25.1 

Stent-assisted coiling of an ICA aneurysm...........................................................................................260

Video 25.2 

Stent-assisted coiling of an ACoA aneurysm........................................................................................264

Video 25.3 

Stent-assisted coiling of a complex ACoA aneurysm.........................................................................267

Video 25.4 

Stent-assisted coiling and flow diversion of a large recurrent complex PCoA aneurysm.......271

Video 25.5 

Stent-assisted coiling of an MCA aneurysm.........................................................................................274

Video 25.6 

Stent-assisted coiling of a recurrent basilar apex aneurysm..........................................................277

Video 25.7 

Y-configuration stent-assisted coiling of a basilar apex aneurysm...............................................281

Video 25.8 

Y-configuration stent-assisted coiling of a recurrent basilar apex aneu­r ysm............................283

Video 26.1 

Flow diversion stenting for cervical ICA aneurysm...........................................................................288

Video 26.2 

Flow diversion stenting for paraclinoid ICA aneurysm....................................................................291

Video 26.3 

Flow diversion stenting for PCoA aneurysm........................................................................................295

Video 26.4 

Simultaneous carotid artery stenting and PCoA aneurysm treatment........................................298

Video 26.5 

Flow diversion stenting for PCoA aneurysm and tortuous carotid artery .................................302

Video 26.6 

Flow diversion stenting for complex ophthalmic aneurysm..........................................................305

Video 26.7 

Flow diversion stenting for residual fusiform MCA aneurysm.......................................................308

Video 26.8 

Flow diversion stenting for recurrent large MCA aneurysm...........................................................311

Video 26.9 

Flow diversion stenting for vertebral artery aneurysm....................................................................315

Video 26.10 

Flow diversion stenting for basilar artery aneurysm......................................................................318

Video 27.1 

Intrasaccular flow diversion for ACoA aneurysm...............................................................................323

Video 27.2 

Intrasaccular flow diversion for MCA aneurysm................................................................................327

Video 27.3 

Intrasaccular flow diversion for PCoA aneurysm...............................................................................330

Video 28.1 

Neck remodeling device-assisted coiling of an MCA aneurysm.....................................................335

Video 28.2 

Neck remodeling device-assisted coiling of a complex MCA aneurysm.......................................337

Video 28.3 

Neck remodeling device-assisted coiling of a basilar apex aneurysm..........................................341

Video Contents Video 28.4 

Neck remodeling device-assisted coiling of a large wide-necked basilar apex aneurysm......343

Video 28.5 

Neck remodeling device-assisted coiling of a wide-necked basilar apex aneurysm................347

Video 29.1 

Mycotic MCA aneurysm treated with liquid embolic agent............................................................352

Video 29.2 

AVM-associated ruptured aneurysm treated with liquid embolic agent.....................................355

Video 29.3 

Ultra-rapid mycotic aneurysm formation treated with liquid embolic agent...........................359

Video 29.4 

De novo formation and ruptured AVM-associated aneurysm treated with liquid embolic agent...................................................................................................................................361

Video 30.1 

Balloon angioplasty for severe intracranial vasospasm....................................................................366

Video 31.1 

Grade V frontal AVM embolization–ophthalmic artery approach................................................374

Video 31.2 

Grade III occipital AVM embolization....................................................................................................377

Video 31.3 

Grade II cerebellar AVM embolization...................................................................................................380

Video 31.4 

Grade V ruptured thalamic AVM embolization...................................................................................383

Video 31.5 

Recurrent facial vascular malformation embolization.....................................................................386

Video 31.6 

Cardiac standstill and transvenous brainstem/thalamic AVM embolization.............................390

Video 31.7 

Very distal cerebellar AVM embolization..............................................................................................393

Video 32.1 

Grade II frontal AVM embolization.........................................................................................................398

Video 32.2 

Curative embolization of a ruptured micro-AVM...............................................................................401

Video 33.1 

Ethmoidal skull base AVF embolization................................................................................................407

Video 33.2 

Type IV dural AVF embolization..............................................................................................................409

Video 33.3 

Type III dural AVF embolization..............................................................................................................412

Video 33.4 

Large tentorial AVF embolization...........................................................................................................415

Video 34.1 

Type IV spinal AVM embolization...........................................................................................................421

Video 34.2 

High-flow spinal epidural AVF embolization.......................................................................................423

Video 34.3 

Pediatric large thoracic AVF embolization...........................................................................................427

Video 35.1 

Facial vein embolization of indirect cavernous carotid fistula.......................................................432

Video 35.2 

Embolization of bilateral direct high-flow CC fistula........................................................................434

Video 36.1 

Sphenopalatine artery embolization for severe epistaxis................................................................442

Video 36.2 

Sphenopalatine artery and maxillary artery embolization for recurrent severe epistaxis....445

Video 37.1 

Intra-axial cerebellar hypervascular tumor embolization..............................................................451

Video 37.2 

Extra-axial posterior fossa hypervascular tumor embolization....................................................454

Video 37.3 

Skull base hypervascular tumor embolization...................................................................................457

Video 38.1 

Carotid body tumor embolization..........................................................................................................462

Video 39.1 

Emergent carotid artery blowout embolization.................................................................................468

xiii

Video Contents

xiv

Video 40.1 

Complication—Femoral artery perforation..........................................................................................480

Video 40.2 

Complication—Intracranial vessel perforation during stent retriever mechanical thrombectomy..............................................................................................................................................484

Video 40.3 

Complication—Thrombus fragmentation/migration during stent retriever mechanical thrombectomy..............................................................................................................................................486

Video 40.4 

Complication—Aneurysm perforation during stent-assisted coiling............................................489

Video 40.5 

Complication—Aneurysm re-rupture during endovascular coiling..............................................493

Video 40.6 

Complication—Acute thromboembolism formation during ruptured aneurysm coiling.......496

Video 40.7 

Complication—Flow diversion stent foreshortening.........................................................................499

Video 40.8 

Complication—Acute fatal basilar artery aneurysm rupture..........................................................503

Video 40.9 

Complication—Retained microcatheter after Onyx AVM embolization.......................................505

Video 40.10 

Complication—Iatrogenic VA dissection managed with flow diversion stent..........................509

Video 40.11 

Complication—Subclavian stent rescue from aortic arch migration..........................................512

Foreword The field of cerebrovascular surgery has undergone a monumental metamorphosis in the last 25 years. It is a source of personal amazement—and a stern reminder of my own ephemeral longevity!—to recollect that the GDC coil became FDA approved the year I started my neurosurgical practice, back in 1995. Creativity, innovation and technical excellence in the endovascular world have not been in short supply since. We will be hard pressed to name a neurosurgical subspecialty that has witnessed more transformation in such little time. Hardly a year goes by where a conceptual breakthrough, clever redesign or technical improvement in neuro-endovascular science does not occur. The field had been heralded with promises of superior outcomes through minimal access means. In most instances, the promises have been and continue to be realized, to the benefit of thousands and millions of patients. Who is the modern endovascular surgeon? He or she is generally a highly motivated, intelligent, innovative, academicallyproductive individual who was attracted to the mesmerizing complexity of cerebrovascular anatomy, physiology and pathologies early on in his or her journey. This thriving discipline is now the domain of neurosurgeons, neuroradiologists and neurologists alike. Their paths were different, but they met at a nexus of sorts—the common ground of stroke, aneurysms, and vascular malformations. They share a common language of catheter names and sizes, flat panel technology, radiation dosimetry, subtle finger ergonomics of wire twisting/pulling/pushing, recanalization scores, and such. They keep up with the ever-changing world of industrial innovations. They lead or participate in numerous clinical trials and bring the full might of Level 1 scientific evidence to bear on clinical endovascular practice. They travel the world teaching others their craft through lectures, cadaveric courses and advanced simulators. There are also some high profile live international courses that have become legendary and a must for any endovascular trainee. Drs. Rangel-Castilla, Siddiqui and Levy represent some of the best and brightest endovascular experts that the field has produced. Through their contributions to the science and craft of endovascular surgery at Buffalo and Mayo they have created, advanced and refined numerous concepts and techniques in this discipline. The remarkable house that Nick Hopkins built in Buffalo in the 1970s has produced many stars indeed that have permeated and reshaped the discipline across this nation. The Hopkins legacy is alive and well under the Levy tenure. This new publication, the Video Atlas of Neuroendovascular Procedures, is a unique undertaking. It capitalizes on the enormous breadth and depth of experience that the authors have garnered over the years,

but then distills it into individual vignettes of cases presented in a very practical way. Not only does the reader have access to chapter-type comprehensive reading material about the entire endovascular field, but also to actual case-specific videos and superb artistic renditions of the angiographic summary for each vignette. The authors talk the talk, but also walk the walk. They include all relevant technical details. They tell us why to do it, why not to do it a different way, how to do it, and lead us by the hand as they show us how they did it. And they do this for every type of case in eight separate thematic sections. What a wonderful idea it was to put this project together. It is a carefully and intelligently designed mix of didactic and practical knowledge. It synthesizes, analyzes, demonstrates, and illustrates all at once; it has something for everyone. As technology constantly transforms itself, with the creation of new devices, it is inevitable that some of the technical aspects presented here will become in time obsolete. That should hardly detract students from wanting to own this atlas, study its every detail and reference the cases— which can be pulled up on their cellphones with a quick scan—as a practical guide to their own practice, providing discussion points with their teachers and peers in their own institutions. And one day, far into the future, when all cerebrovascular pathologies will be curable with a pill or genetic probe, when the clipper will put down the clip, when the coiler will put down the coil, at least our then-retiring readers will own a piece of history! They will be able to show their grandchildren how early in the 21st century some of the most gifted endovascular practitioners battled the vascular beasts with superb ingenuity, relentless courage and uncommon dexterity. I congratulate the authors for this labor of love. The sweat behind it has not gone unnoticed. It is there in every aspect of each case, sometimes obvious and sometimes subtle. But what readers will need to realize as they watch and learn from the masterful execution of each featured case, is that behind it is a mountain of experience, that the path to mastery is paved with discoveries, sometimes welcome and sometimes not, and it takes supremely committed and astute surgeons, like the authors, to grow and blossom after each realized triumph and each encountered disaster. This publication will undoubtedly help students of neuroendovascular surgery shorten their journey towards mastery. Jacques J. Morcos, MD, FRCS, FAANS Professor and Co-Chairman Department of Neurosurgery University of Miami

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Preface In the 1990s, early neuroendovascular techniques underwent an evolutionary leap forward. From a developing modality, they rapidly matured and dramatically expanded in capability to the point that they substantially changed the approach to most neurovascular diseases. The goal of the Video Atlas of Neuroendovascular Procedures is to present basic and complex neuroendovascular procedures differently from traditional textbooks that tend to emphasize natural history, physiology, and morphology. Rather, our book will present in a concise manner a clinical case, relevant noninvasive neuroimaging findings, neuroendovascular procedure planning, and the rationale for endovascular intervention. Each case includes a list of devices and materials used to accomplish the task and an explanation for using those specific tools based on the patients’ vascular anatomy and pathology. Most importantly, each case is accompanied by an edited and narrated high-definition video demonstrating step-wise sequences of the procedure. The book is also interactive; each video is presented with a QR code that can be scanned with a smart phone or tablet playing the video immediately in the palm of the reader’s hand. Readers thus can read the text and explanation while simultaneously watching the video on an electronic device. Each case features a professional illustration summarizing the procedure in a single exquisite image. This book represents a compendium of current knowledge to serve as reference for those already practicing and as a text for study for those entering the field. It is designed to be both a comprehensive reference and a focused tool. It can serve as a text that one would read cover-to-cover or as a go-to resource for the management of a specific case. In both roles, the text is also designed to benefit medical students, residents, and fellows in need of a quick reference to pertinent must-know information. The text is organized in 8 sections according to diagnosis, topics, and

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procedure types. It covers all known neuroendovascular interventions. Section I includes vascular access, from traditional femoral artery access to increasingly used radial artery and direct carotid access. Section II covers diagnostic procedures: cerebral, spinal, arteriograms, venograms, balloon test occlusions, and petrosal sinus sampling. Section III contains extracranial vessel angioplasty and stenting such as carotid artery stenting with distal or proximal protection and flow arrest techniques, and the less commonly performed vertebral artery and venous sinus stenting. Section IV covers acute stroke procedures such as mechanical thrombectomy with or without a stent retriever, in anterior or posterior circulation, intracranial or extracranial stenting in emergent situations, and angioplasty for intracranial atherosclerosis. Section V covers all endovascular techniques for the treatment of intracranial aneurysms: coiling, balloon- or stent-assisted coiling, flow diversion, liquid embolic agents, and novel devices such as aneurysm neck reconstruction and intrasaccular flow-disruption devices. Section VI covers endovascular embolization of intracranial and spinal arteriovenous malformations and fistulas, which are relatively uncommon but challenging lesions to manage. Section VII includes head and neck embolization of hypervascular tumors, epistaxis, and carotid blow out. The last section, and perhaps the most interesting, Section VIII, covers common complications in neuroendovascular surgery and their management. We hope you find this volume interesting and that you will enjoy reading this book as much as we enjoyed putting it together for you. Leonardo Rangel-Castilla Adnan H. Siddiqui Elad I. Levy

Acknowledgments We thank all enthusiastic neurosurgeons, interventional radiologists, neurologists, fellows, and residents for their contributions to this volume. Without their participation, this book would never have been possible. We thank medical illustrator Jennifer Pryll, a talented artist who created intelligible illustrations from complex neuroendovascular procedures and whose profound knowledge of anatomy resulted in superb neurovascular illustrations, including the cover design. We also thank editorial assistants Elaine C. Mosher MLS, W. Fawn Dorr BA, and Debra J. Zimmer for correcting and polishing our work to ensure accuracy and consistency, and medical illustrator Paul H. Dressel BFA for his assistance with video capturing. Our immense gratitude goes to the technicians and nurses of neurointerventional angiography suites at Mayo Clinic, Rochester MN, and Gates Vascular Institute, Buffalo NY, for assisting with video recording even in difficult emergency situations.

Our dear friends from Thieme need to be recognized for their continued commitment to quality publishing: thanks to Tim Hiscock, leader of the team, who enabled this whole endeavor and to Sarah Landis for her patience throughout the material compilation and editorial process and for always giving us the encouragement we needed to see the project through to completion. Lastly, we thank our patients who allow us to serve them and inspire us to labor on into the darkness, shedding what light we can; our colleagues, who strive alongside us every day carrying out the patient care described in this book; our families, who with great love and patience support us in these endeavors and make it all possible; and you, the reader, who is the very reason we brought this volume into existence.

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Contributors Jason M. Davies, MD, PhD Assistant Professor Cerebrovascular and Skullbase Neurosurgery Departments of Neurosurgery and Biomedical Informatics Director of Cerebrovascular Microsurgery Director of Endoscopy, Kaleida Health Research Director, Jacobs Institute State University of New York, Buffalo Buffalo, New York Enrico Giordan, MD Research Fellow Department of Neurosurgery Mayo Clinic Rochester, Minnesota L. Nelson Hopkins, MD, FACS SUNY Distinguished Professor Founder, Gates Vascular and Jacobs Institute CSO, Jacobs Institute UB Neurosurgery SUNY Buffalo Buffalo, New York Willem Jan van Rooij, MD, PhD Interventional Neuroradiology Elisabeth - Tweesteden Ziekenhuis Tilburg, The Netherlands Giuseppe Lanzino, MD Professor of Neurological Surgery and Radiology Mayo Clinic Rochester, Minnesota Elad I. Levy, MD, MBA, FACS, FAHA Professor and Chair Department of Neurosurgery and Radiology State University of New York Director of Interventional Stroke Services Kaleida Health Network Buffalo, New York Stephan A. Munich, MD Assistant Professor Department of Neurosurgery Rush University Medical Center Chicago, Illinois Alexander Neary, BS Medical Student Department of Neurosurgery Jacobs School of Medicine and Biomedical Sciences Buffalo, New York

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Jo P. Peluso, MD, PhD Interventional Neuroradiology Elisabeth - Tweesteden Ziekenhuis Tilburg, The Netherlands Gary B. Rajah, MD Neurovascular Fellow Department of Neurosurgery Jacobs School of Medicine and Biomedical Sciences University at Buffalo Department of Neurosurgery Gates Vascular Institute at Kaleida Health Buffalo, New York Leonardo Rangel-Castilla, MD Assistant Professor Department of Neurosurgery and Radiology Mayo Clinic Rochester, Minnesota Consultant Neurosurgeon Private Practice San Luis Potosi, SLP, Mexico Lorenzo Rinaldo, MD, PhD Resident Department of Neurosurgery Mayo Clinic Rochester, Minnesota Hussain Shallwani, MD Resident Department of Neurosurgery Jacobs School of Medicine and Biomedical Sciences University at Buffalo Buffalo, New York Adnan H. Siddiqui, MD, PhD, FACS, FAHA, FAANS Professor and Vice Chair Director Neuroendovascular Fellowship Program Department of Neurosurgery and Radiology State University of New York Buffalo, New York Michael K. Tso, MD, PhD Fellow Department of Neurosurgery University at Buffalo Buffalo, New York

Contributors Kunal Vakharia, MD Endovascular Fellow Department of Neurosurgery University at Buffalo Buffalo, New York

Muhammad Waqas, MBBS Endovascular Fellow  Department of Neurosurgery University at Buffalo Buffalo, New York

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Part I



1 Femoral Artery Access and Closure

Vascular Access



2 Femoral Vein Access

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3 Brachial Artery Access

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4 Radial Artery Access

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5 Direct Carotid Artery Access

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1  Femoral Artery Access and Closure Gary B. Rajah and Leonardo Rangel-Castilla

General Description The most common vascular access approach used for diagnostic cerebral angiography and neuroendovascular interventions is the common femoral artery (CFA). Understanding the anatomy of the femoral artery and related anatomic structures is fundamental to any neurointerventionist to minimize complications during vascular access.

Indications Femoral artery access is indicated for any diagnostic cerebral angiogram. It is also indicated for most neuroendovascular procedures that require a 7 French (F) or larger sheath for access.

Neuroendovascular Anatomy The CFA is a continuation of the external iliac artery. The transition from the CFA to the external iliac artery is marked by the inguinal ligament that extends from the bony anterior superior iliac spine to the pubic tubercle. The CFA extends from the inguinal ligament and crosses at the medial third of the femoral head. At the junction of the femoral neck and lesser trochanter, it bifurcates into the superficial femoral artery (SFA) and profunda femoral artery (PFA). Small branches from the external iliac artery, such as the circumflex iliac and deep epigastric, should be identified to avoid placing the access sheath within them and causing vessel rupture and retroperitoneal hematoma.

Specific Technique and Key Steps It is important to obtain the patient’s history of previous femoral artery access, femoral bypass, stent placement, or surgery at the inguinal region. A complete examination of the groin area with documentation of the femoral, popliteal, and pedal pulses is essential. To maximize the efficiency of neuroendovascular procedures, we routinely obtain percutaneous access through the right femoral artery (Fig. 1.1–1.3 and Video 1.1–1.3), unless a contraindication exists (i.e., scarring from a previous surgery, absence of a femoral pulse, multiple previous punctures/closure device, or pseudoaneurysm formation). 1. After the groin is prepared and draped in sterile fashion, the site of puncture is identified using bony landmarks and confirmed radiographically with an X-ray (Fig. 1.2, 1.3 and Video 1.2, 1.3). The anterior superior iliac spine and the pubic symphysis are connected by the inguinal ligament, which marks the superior border of the CFA. This can be palpated in most individuals. 2. The CFA runs medial to the center of the femoral head. This site is found under X-ray using a hemostat for localization and marked. The lower third of the femoral head is the ideal site for vessel puncture. 3. The CFA pulse is elicited, and local anesthesia is infiltrated in the skin and subcutaneous tissue. A single wall puncture of the CFA is performed with a microneedle (21-gauge micropuncture kit) at a 45° angle with the bevel facing up. A single anterior wall puncture technique is used. 4. Once pulsatile bright red blood is encountered, a microwire (0.010inch diameter Cope Mandril, Cook Medical) is advanced through the microneedle. If resistance is noted, the process is halted, and the microwire trajectory is confirmed with an X-ray. After the trajectory is confirmed, the wire is advanced up and to the left toward the iliac artery and abdominal aorta, avoiding the small lateral side branches. The microneedle is removed and an intermediate dilator (4–5F

microsheath) is inserted. The introducer is removed and a 30-cm J-wire is inserted. The intermediate dilator/microsheath is exchanged for a sheath (4–6F). For diagnostic cerebral angiography, a 5F sheath is used for adult cases, and a 4F sheath is used for pediatric cases. Longer femoral sheaths (>25 cm) are considered for patients who are obese or those with very tortuous anatomy (Fig. 1.1, Video 1.1). 5. If a larger diameter femoral sheath is required (7–9F), an intermediate dilator and a longer, stiffer wire should be used (Fig. 1.2 and Video 1.2). 6. After arterial access is established, a femoral artery angiogram (run) is performed before proceeding with the case. We assess for femoral artery patency, stenosis, and dissection, as well as possible extravasation. The groin run is needed to determine whether the arteriotomy can be closed percutaneously with a closure device (e.g., AngioSeal, St. Jude Medical; Perclose, Abbott Vascular; Mynx, Cardinal Health; or Catalyst, Cardiva Medical) (Fig. 1.1–1.6 and Video 1.1–1.6).

Device Selection 1. 4–6F femoral sheath requires the following: a. Micropuncture kit (microneedle, microwire, microsheath, intermediate sheath, J-wire). b. 4–6F femoral sheath. 2. 7–9F femoral sheath requires the following: a. Micropuncture kit (microneedle, microwire, microsheath, intermediate sheath, J-wire). b. Intermediate dilator (7F). c. Longer, stiffer wire (i.e., short Amplatz wire, Stiff Glidewire).

Closure Device Selection 1. The AngioSeal device utilizes a collagen sponge that is sandwiched between the inner and outer vessel wall (Fig. 1.4 and Video 1.4). We typically use this device for larger arteriotomies (i.e., 8–9F) and in patients with hemostasis-related issues. 2. The Mynx percutaneous closure device is used for smaller (i.e., 5–6F) arteriotomies typically after diagnostic procedures (Fig. 1.5, 1.6 and Video 1.5, 1.6). The device utilizes an extravascular sealant, and some manual pressure is usually required after placement. In very thin patients, the sealant can extrude to the skin and must be wiped away and more manual pressure applied. The Catalyst device is also utilized for smaller arteriotomies; it requires removal of the device 10 minutes after placement and the application of manual pressure for 20 minutes thereafter. 3. The Perclose device is designed to deliver a prolene stitch at the arteriotomy site. This device is commonly used for 6F openings. The patient is typically given one dose of antibiotics as the stitch is nonabsorbable.

Pearls • Prepare and drape both groins in patients with weak or nonpalpable femoral pulses or patients with possible difficult access (i.e., obese or peripheral vascular disease) (Fig. 1.2 and Video 1.2). With the use of ultrasound imaging, identify the femoral artery; use an echogenic insulated ultrasound needle for this purpose. • If resistance is encountered while advancing the microwire or needle wire, stop! Inadvertent advancement within a dissection flap or small caliber vessel is likely when microwire resistance is

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I  Vascular Access ­ ncountered. Advance the wire under fluoroscopy. Use a nitinol e wire; these wires are longer and firmer. • For pediatric cases, use ultrasound imaging for identification of the femoral artery (Fig. 1.3 and Video 1.3). In these cases, it is not uncommon to puncture the posterior wall inadvertently because of the small artery size. Some interventionists prefer not to use a sheath, and to use the diagnostic catheter directly. • For obese patients, use long sheaths. Short sheaths can become kinked or may pull out inadvertently. • Avoid puncturing femoral artery stents. Obtain access above or below the stent or the contralateral femoral artery. Puncture of vascular grafts is acceptable, but special care should be taken with sterile technique and closure. If access was gained through a vascular graft, closure often requires an extra amount of manual

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c­ ompression. We do not recommend the use of any closure device for these cases. • Pulsatile masses over previous puncture sites should be evaluated with computed tomography angiography of the pelvis or abdomen to determine whether a pseudoaneurysm is present. Another possibility for the evaluation of these masses involves puncturing the contralateral groin and performing a formal femoral angiogram on the suspicious side. Treatment options for pseudoaneurysms include ultrasonic compression, ultrasonic compression with thrombin injection, stenting, and, last, vessel reconstruction. • Postoperative back pain should be taken seriously as this can be a sign of retroperitoneal hematoma, often from a high-level puncture in which it was difficult to achieve hemostasis. Immediate evaluation with computed tomography imaging is needed.

1  Femoral Artery Access and Closure

CASE 1.1 Femoral Artery Access

Case Overview • A 35-year-old woman presents for evaluation of nonruptured brain arteriovenous malformation. She has no significant past medical history.

• Patient requires a diagnostic cerebral angiogram for further evaluation.

Fig 1.1a  Two-hand technique for right femoral artery pulse identification.

Fig 1.1b  Right femoral artery access with a 21-gauge needle in a 45 degree angulation.

Fig 1.1c  A microwire (0.010-inch diameter) is advanced through the microneedle followed by a 4F microdilator.

Fig 1.1d  The intermediate dilator/microsheath is exchanged for a sheath (4-6F). For diagnostic cerebral angiography, a 5F sheath is used for adult cases.

Video 1.1  Femoral artery access

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I  Vascular Access

Fig 1.1e  A femoral artery angiogram is performed before proceeding with the case to confirm adequate sheath placement, no injury or perforation to the vessel.

Fig 1.1f  Artist’s illustration of femoral artery access.

Fig 1.1g  Intraoperative picture of femoral artery access.

Device List

Device Explanations

• Standard femoral artery access. • Micropuncture kit. – Microneedle (21-gauge). – Microwire (0.010-inch diameter Cope Mandril, Cook Medical). – Microsheath (4F). • Intermediate sheath (if a large sheath is required (8 or 9F). • 30 cm J-wire to exchange the dilator for a larger sheath. • 4–6F femoral sheath.

Standard femoral artery access is a routine procedure in neuroendovascular surgery. Different techniques can be used. We favor the use of a micropuncture kit because if a smaller branch is punctured accidently or the puncture site is above the inguinal ligament, it is easier to achieve hemostasis than a larger gauge needle.

Tips, Tricks & Complication Avoidance • Always prepare and drape both groins. • Use ultrasound imaging for pediatric patients, patients with peripheral vascular disease, obese patients, or patients with pulses hard to palpate. • If resistance is encountered while advancing the microwire or sheath, stop and reassess. • For obese patients, use long sheaths.

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• Puncture of vascular grafts is acceptable, but special care should be taken with sterile technique and manual pressure closure. • Pulsatile masses over previous puncture sites should be evaluated with noninvasive imaging for angiogram from the contralateral femoral artery. • Patients with intra- or postoperative back pain should be taken seriously as this can be a sign of retroperitoneal hematoma.

1  Femoral Artery Access and Closure

CASE 1.2 Femoral Artery Access

Case Overview • A 68-year-old woman presents for evaluation of carotid artery stenosis and possible occlusion. She has past medical history of hypertension, diabetes and hypercholesterolemia.

• She had previous right hip replacement surgery. • Patient requires a diagnostic cerebral angiogram for further evaluation.

Fig 1.2a  Right femoral artery pulse identification and local anesthetic infiltration.

Fig 1.2b  A microwire (0.010-inch diameter) is advanced through the microneedle.

Fig 1.2c  The microwire is inserted under direct fluoroscopy visualization.

Fig 1.2d  A 5F sheath is inserted.

Video 1.2  Femoral artery access 2

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I  Vascular Access

Fig 1.2e  A femoral artery angiogram is performed.

Fig 1.2f  Artist’s illustration of femoral artery access on a patient with previous hip surgery.

Fig 1.2g  Intraoperative picture of femoral artery access.

Device List

Device Explanation

• • • • • • • •

Standard femoral artery access is a routine procedure in neuroendovascular surgery. It is not uncommon to have patients with previous surgery around the femoral artery (hip replacement, femoral bypass). Direct visualization under fluoroscopy of the wires is recommended. We favor the use of a micropuncture kit because if a smaller branch is punctured accidently or the puncture site is above the inguinal ligament, it is easier to achieve hemostasis than a larger gauge needle.

Standard femoral artery access. Micropuncture kit. Microneedle (21-gauge). Microwire (0.010-inch diameter Cope Mandril, Cook Medical). Microsheath (4F). Intermediate sheath (if a large sheath is required (8 or 9F). 30 cm J-wire to exchange the dilator for a larger sheath. 4–6F femoral sheath.

Tips, Tricks & Complication Avoidance • In cases of difficult punctures, leave the needle in place and watch it. When the needle is near the artery, the needle will pulsate, typically toward the artery. • If any resistance is felt while advancing the microwire or J-wire, consider advancing under fluoroscopy and use of nitinol wire. Nitinol wires are longer and firmer and can sometimes pass through stenotic or tortuous vessels.

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• Risk factors for a difficult femoral artery access include previous hip or femoral artery surgery, obesity, local atherosclerotic plaques, and calcified vessels. • Keep in mind that patients on antiplatelet or anticoagulation drugs could easily develop hematomas, and similarly, patients who had received IV thrombolysis.

1  Femoral Artery Access and Closure

Case Overview

CASE 1.3 Pediatric Femoral Artery Access

• A 2-year-old child was brought to the emergency room with altered mental status and agitation. Neurologically he was alert but somnolent, with no focal deficits. • No past medical history of importance.

• Computed tomography demonstrated diffuse subarachnoid hemorrhage. • Patient requires a diagnostic cerebral angiogram for further evaluation.

Fig 1.3a  Right femoral head and neck identification.

Fig 1.3b  Right femoral artery pulse identification.

Fig 1.3c  A microwire (0.010-inch diameter) is advanced through the microneedle.

Fig 1.3d  The microwire is inserted under direct fluoroscopy visualization.

Video 1.3  Pediatric femoral artery access

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I  Vascular Access

Fig 1.3e  A 4F sheath is inserted.

Fig 1.3g  Artist’s illustration of pediatric femoral artery access.

Fig 1.3f  A femoral artery angiogram.

Device List

Device Explanation

• Standard femoral artery access. • Micropuncture kit. – Microneedle (21-gauge). – Microwire (0.010-inch diameter Cope Mandril, Cook Medical). – Microsheath (4F). • Intermediate sheath (if a large sheath is required (8 or 9Fr). • 30 cm J-wire to exchange the dilator for a larger sheath. • 4-6F femoral sheath.

Standard femoral artery access is a routine procedure in neuroendovascular surgery, including pediatric patients. We routinely use ultrasound to identify the femoral artery. Direct visualization under fluoroscopy of the wires is most strongly recommended for pediatric patients. Similarly to adults, we favor the use of a micropuncture kit.

Tips, Tricks & Complication Avoidance • Similar to adults, always prepare and drape both groins. • Use ultrasound to identify the femoral artery in pediatric patients. • Observe the wire advancing under direct fluoroscopy. Perforation or muscular branch injury could occur inadvertently.

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• Use of femoral sheath is ideal, but direct guide or diagnostic catheter use with no femoral sheath is an acceptable alternative. • Have an exact count of the amount of contrast being used. The amount of contrast allowed is based on patient’s weight. • Limit the radiation dose as low as possible.

1  Femoral Artery Access and Closure

Case Overview

CASE 1.4 Percutaneous Closure AngioSeal

• A 59-year-old male underwent a diagnostic cerebral angiogram for evaluation of multiple intracranial aneurysm. • During the evaluation one of the aneurysms was treated with endovascular coiling.

• A 6F sheath and a 6F guide catheter were used for access. 5,000 units of heparin were administered during the procedure. • Once the procedure was performed, a percutaneous closure device was used to close the femoral arteriotomy.

Fig 1.4a  Assembling device.

Fig 1.4b  Exchange wire.

Video 1.4  Percutaneous closure device (AngioSeal)

Fig 1.4c  Closure device Sheath.

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I  Vascular Access

Fig 1.4d  Closure device deployment.

Fig 1.4f  Artist’s illustration of percutaneous closure device (AngioSeal).

Fig 1.4e  Closure device deployed.

Device List And Explantion

Device Explanation

AngioSeal is a collagen hemostatic puncture closure device most widely used. The components include a rectangular anchor, a collagen plug, and a suture. All these components are absorbable within 60 to 90 days.

• AngioSeal closure device. • Local anesthetic.

Tips, Tricks & Complication Avoidance • Criteria for AngioSeal usage. – The femoral artery diameter should measure 3 mm or more. – The arteriotomy site should be no more than 2 cm above or below the femoral artery bifurcation.

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The arteriotomy should be at the femoral artery, not at one of its branches. • Make sure there is at least a 2–3 mm skin incision before the AngioSeal is deployed, otherwise the collagen plug could get caught on the skin and the patient could develop a large hematoma. –

1  Femoral Artery Access and Closure

Case Overview

CASE 1.5 Percutaneous Closure MynxGrip

• A 66-year-old male underwent a diagnostic cerebral angiogram for evaluation of intracranial atherosclerosis. • A 5F sheath and a 5F guide catheter were used for access and angiogram. 1,500 units of heparin were administered during the procedure.

• Once the procedure was performed, a percutaneous closure device was used to close the femoral arteriotomy.

Fig 1.5a  MynxGrip device.

Fig 1.5b  Prepping the distal balloon.

Video 1.5  Percutaneous closure device (Mynx) I

Fig 1.5c  Device through the existent femoral sheath.

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I  Vascular Access

Fig 1.5e  Closure device deployed.

Fig 1.5d  Closure device deployment.

Fig 1.5f  Artist’s illustration of percutaneous closure device (MynxGrip).

Device List

Device Explanation

• Mynx closure device. • Local anesthetic.

The most recently developed Mynx device consists of polyethylene glycol sealant, a water-soluble, bio-inert, nonthrombogenic polymer. The sealant is deploy outside the artery, while the arteriotomy site is temporarily occluded within the artery with the system’s semicompliant balloon. The Mynx sealant fully resorbs within 30 days.

Tips, Tricks & Complication Avoidance • Compared to other percutaneous closure devices, MynxGrip is gentle on the artery and causes less pain during deployment.

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• We recommend to hold gentle pressure on the arteriotomy site after Mynx deployment for 1–2 min, especially if heparin was used during the procedure.

1  Femoral Artery Access and Closure

Case Overview

CASE 1.6 Percutaneous Closure MynxGrip

• A 31-year-old female underwent a diagnostic cerebral angiogram for evaluation of a brain arteriovenous malformation. • A 5F sheath and a 5F guide catheter were used for access and the angiogram. 1,000 units of heparin were administered during the procedure.

• Once the procedure was performed, a percutaneous closure device was used to close the femoral arteriotomy.

Fig 1.6a  5Fr femoral sheath within the artery.

Fig 1.6b  Prepping distal balloon.

Fig 1.6c  Device within the femoral sheath.

Video 1.6  Percutaneous closure device (Mynx) II

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I  Vascular Access

Fig 1.6d  Closure device deployed.

Fig 1.6e  Closure device deployed.

Fig 1.6f  Artist’s illustration of percutaneous closure device deployment (MynxGrip).

Device List And Explanation

Device Explanation

• MynxGrip closure device. • Local anesthetic.

The MynxGrip comes in 5, 6, 7F models. It is indicated for interventional and diagnostic procedures and is recommended for closure of borderline-caliber arteries (4.5–5.0 mm). The balloon is checked for leaks by inflating it until the black marker on the inflation indicator is fully visible, then deflated.

Tips, Tricks & Complication Avoidance • Closure devices aim to replace manual compression with an easier, more convenient alternative that can save time and effort and make the patient more confortable, without increasing the rate of complications.

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• Although rare, percutaneous closure devices could get infected. Prior to deployment, clean the groin area appropriately. • Check pedal pulses after deployment.

2  Femoral Vein Access Gary B. Rajah and Leonardo Rangel-Castilla

General Description The most common approach for vascular access used for diagnostic cerebral venography and neuroendovascular venous interventions is the common femoral vein (CFV). It is essential that the neurointerventionist understands the anatomy of the femoral vein and the anatomic structures related to it to minimize complications during vascular access.

Indications Femoral vein access is indicated for any diagnostic cerebral venogram. The most common clinical indications include arteriovenous malformation or dural arteriovenous fistula venous embolization, inferior petrosal sinus sampling, venous sinus pressure monitoring, venous sinus thrombosis intervention, and venous sinus stenting.

Neuroendovascular Anatomy The CFV is a continuation of the external iliac vein; this transition is anatomically marked by the inguinal ligament that extends from the bony anterior superior iliac spine to the pubic tubercle. The CFV extends from the inguinal ligament, and crosses at the medial third of the femoral head. At the junction of the femoral neck and lesser trochanter, the CFV bifurcates into the superficial femoral vein and profunda femoral vein. Small branches from the external iliac vein, such as the circumflex iliac and deep epigastric, are important to recognize to avoid placement of the access sheath within one of these small branches, resulting in vessel rupture and retroperitoneal hematoma. The CFV lies medial to the common femoral artery (CFA) and can be located by palpating the pulse of the artery and puncturing medial to the artery. It is important to note that the CFV communicates with the inferior vena cava on the right side of the spinal column, which in turn communicates with the superior vena cava and right and left brachiocephalic veins.

Specific Technique and Key Steps It is important to obtain the patient’s history of previous arterial or venous femoral access, femoral bypass, stent placement, or any surgery at the inguinal region. A complete examination of the groin area with documentation of the femoral, popliteal, and pedal pulses is essential. For maximal efficiency, we routinely use the right femoral vein, unless there is a contraindication (e.g., scars from previous surgery, lack of a femoral pulse, multiple previous punctures/closure device placement, pseudoaneurysm, fistula formation, or history of lower-extremity deep vein thrombosis) (Fig. 2.1 and Video 2.1). 1. After the groin is prepared and draped, the site of the puncture is found by using bony landmarks. Then the site is confirmed radiographically with an X-ray. The anterior superior iliac spine and the pubic symphysis are connected by the inguinal ligament that marks the superior border of the CFV. This can be palpated in most individuals (Fig. 2.1 and Video 2.1). 2. The CFV runs medial to the CFA. This site is found under X-ray using a hemostat and it is marked. The lower third of the femoral head is the ideal site for vessel puncture because the vein is com-

pressible here. The CFV is located 2 cm medial and caudal to the CFA pulse. Ultrasound imaging is useful for identification of the CFV and CFA. 3. The skin and subcutaneous tissue over the CFV is infiltrated with an anesthetic agent. A single-wall puncture of the CFV is performed with a microneedle (21-gauge micropuncture kit) in a 45° angle with the bevel facing up. 4. When nonpulsatile dark red blood is encountered, a (0.010 Cope Mandril, Cook Medical) microwire is advanced through the needle. If resistance is noted, stop! Confirm the microwire trajectory with an X-ray. The wire should go up and to the patient’s right side toward the iliac vein and inferior vena cava, avoiding the small lateral side branches. The needle is removed and an intermediate dilator (4–5F microsheath) is inserted. The introducer is removed and a J-wire is inserted. The microsheath is exchanged for a 4–6F sheath. For a diagnostic cerebral venogram, we prefer a 5F sheath. We prefer longer femoral sheaths (> 25 cm) for obese patients or patients with very tortuous anatomy. For intervention, we consider 80-cm Cook Shuttle sheaths (Cook Medical). 5. After venous access has been established, we routinely perform a femoral venogram before proceeding with the case. We assess for CFV patency, stenosis, dissection, and possible extravasation (Video 2.1). We do not use a closure device for venous punctures, and manual pressure is utilized for hemostasis.

Device Selection 1. 4–6F femoral sheath requires the following: a. Micropuncture kit (microneedle, microwire, microsheath [intermediate sheath], J-wire). b. 4–6F femoral sheath or Cook Shuttle sheath.

Pearls • Prepare and drape both groins in patients with weak or nonpalpable femoral pulses or patients with possible difficult access (e.g., obese patients or patients with peripheral vascular disease). Use ultrasound imaging to identify the CFA and CFV. The CFV is compressible; the CFA is not compressible. The use of an echogenic insulated ultrasound needle is recommended. • If resistance is encountered while advancing the microwire, stop! ­Inadvertent advancement within a dissection flap or small caliber vessel is likely when microwire resistance is encountered. Advance the wire under fluoroscopy. Use a nitinol wire; they are longer and firmer than standard microwire. • Always use an ultrasound for pediatric cases. It is possible to puncture the posterior wall inadvertently because of the child’s small vein size. Some interventionists prefer not to use the sheath and directly utilize the diagnostic catheter. • Use long sheaths in obese people (> 25 cm). Short sheaths can kink, or may pull out inadvertently. • Improper manual pressure can still result in retroperitoneal hematoma. It typically has a slower presentation than an arterial puncture.

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I  Vascular Access

CASE 2.1 Femoral Vein Access

Case Overview • A 48-year-old woman with the clinical diagnosis of idiopathic intracranial hypertension and a magnetic resonance imaging with transverse/sigmoid junction stenosis presents for evaluation of possible venous sinus stenting.

• She has past medical history of obesity and migraines. • Patient requires a diagnostic cerebral venogram for further evaluation and venous pressure measurement.

Fig 2.1a  Identifying femoral artery and vein.

Fig 2.1b  Accessing the femoral vein.

Fig 2.1c  Wiring the femoral vein under fluoroscopy.

Fig 2.1d  Wiring the inferior vena cava.

Video 2.1  Femoral vein access

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2  Femoral Vein Access

Fig 2.1e  Artist’s illustration of femoral vein access.

Device List

Device Explanation

• Standard femoral vein access. • Micropuncture kit. – Microneedle (21-gauge). – Microwire (0.010-inch diameter Cope Mandril, Cook Medical). – Microsheath (4F). • Intermediate sheath (if a large sheath is required (8 or 9F). • 30 cm J-wire to exchange the dilator for a larger sheath. • 4–6F femoral sheath.

Femoral vein access is routinely performed for neuroendovascular procedures involving the venous system, including venous sinus stenting, petrosal sinus sampling, transvenous embolization of arteriovenous malformations, and fistulas. The Seldinger technique is used for vein access similarly to femoral artery access. Ultrasound is useful on identifying the femoral vein. An alternative to the ultrasound in identifying the femoral vein is anatomical landmarks. In adults, the vein is 2 cm medial and 2 cm caudal to the femoral artery, a needle connected to a syringe is used to access the vein. Closure of the femoral vein is always with manual pressure; percutaneous closure devices cannot be used.

Tips, Tricks & Complication Avoidance • Use of ultrasound is strongly recommended when the vein cannot be found after two to three attempts or in patients with obesity, previous groin surgery, or patients taking anticoagulants.

• If any resistance is felt while advancing the microwire or J-wire, consider advancing under fluoroscopy. The wire could have gone inadvertently into a small vein or directed caudally instead of rostrally

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3  Brachial Artery Access Jason M. Davies

General Description Neurointerventionists are turning to alternative vascular access routes because of patient body habitus, complex anatomy, and the risks associated with traditional femoral artery approaches. This follows a general trend in which the cardiology literature is increasingly adopted in the neurointerventional field. Understanding the anatomy of the upper arms, as well as indications and potential pitfalls for brachial artery access, will allow neurointerventionists to achieve optimal benefits through this access route.

Indications Brachial access is indicated when intervention requires the use of largebore guide catheters and if the patient’s habitus makes femoral artery access either difficult or high-risk. Furthermore, anatomic considerations, such as accessing the vertebral artery or aortic arch calcification, can make brachial access superior to transfemoral routes.

Device Selection

The brachial artery is the major blood vessel of the upper arm. It is a continuation of the axillary artery that traverses the cubital fossa. Distally, it separates into the radial and ulnar arteries. The median nerve lies in close proximity to the brachial artery and crosses the medial side of the artery anterior to the elbow.

1. 4–6F femoral sheath insertion requires the following: a. Micropuncture kit (microneedle, microwire, microsheath [intermediate sheath], J-wire). b. 4–6F femoral sheath. 2. 7–9F femoral sheath insertion requires the following: a. Micropuncture kit (microneedle, microwire, microsheath [intermediate sheath], J-wire). b. Intermediate dilator (7F). c. Support wire (i.e., short Amplatz Super Stiff wire, Boston Scientific; Stiff Glidewire Terumo). d. 7–9F sheath.

Specific Technique and Key Steps

Arterial Closure

A complete examination of the upper-extremity vasculature should be performed, including palpating the brachial, ulnar, and radial arteries, as well as checking for capillary refill (Fig. 3.1 and Video 3.1). For ergonomic reasons, the right brachial artery is commonly chosen; however, the left brachial artery may be preferable when pursuing access to the left vertebral artery. 1. After the upper arm is prepared and draped, using a combination of palpation and ultrasound examination, the brachial artery pulse is identified. Ideally, the entry needle should gain access above the biceps tendon, avoiding the median nerve. Ultrasound is useful for avoiding puncture injuries to the median nerve, which can cause vessel injury. Once the puncture site has been selected, a local anesthetic is infiltrated (Video 3.1). 2. Using a microneedle (i.e., 21-gauge micropuncture kit), a single wall arterial puncture of the brachial artery is performed at a 45° angle with the bevel facing up. 3. Once the return of brisk, pulsatile, bright red blood is established through the micropuncture needle, a 0.010-inch microwire is advanced through the needle. If resistance is noted, the practitioner should stop and redirect the needle. Once the wire has been advanced several centimeters, a fluoroscope is used to confirm the location of

We typically do not use arterial closure devices for brachial artery access sites because closure complications can lead to ischemia and compartment syndrome. Instead, we apply manual compression for 20–30 minutes. If the patient received heparin for the procedure, we suture the sheath in place and check serial partial thromboplastin times until the values normalize (typically at 25–30 seconds), after which the sheath may be removed.

Neuroendovascular Anatomy

20

the wire. The needle is removed, and an intermediate 4–5 French (F) marker sheath dilator is inserted. The introducer that comes with the sheath dilator is then removed, and a J-tipped wire is inserted through the sheath. The sheath is then exchanged for the procedural sheath of choice. For diagnostic procedures, typically a 5F sheath is chosen; however, the brachial artery can support up to a 9F sheath for intervention. The insertion of larger sheaths (8–9F) often requires the use of an intermediate dilator and a longer, stiffer wire to upsize to the final sheath size (Fig. 3.1 and Video 3.1). 4. After arterial access has been established and before proceeding with the case, we routinely perform a brachial artery angiographic run. We assess brachial artery patency, stenosis, dissection, and possible extravasation (Video 3.1).

Pearls • If resistance is encountered while advancing the microwire or needle wire, stop! When microwire resistance is encountered, it often suggests that one is advancing within a dissection flap or small caliber vessel. Advance the wire under fluoroscopy. Use a nitinol wire; they are longer and firmer (Video 3.1). • Use long sheaths for vertebral, brachiocephalic, or subclavian stenosis because they will provide good support at the site of intervention without the need for a long guide catheter. • Care should be taken in selecting the brachial artery access route because vessel injury can result in hand or finger ischemia.

3  Brachial Artery Access

Case Overview

CASE 3.1 Brachial Artery Access

• A 75-year-old man presents for evaluation of carotid artery stenosis and possible occlusion. He has a past medical history of hypertension and coronary and peripheral artery disease. He had bilateral femoral artery bypass and grafting several years ago.

• Patient requires a diagnostic cerebral angiogram for further evaluation. • Because of his past medical and surgical history the angiogram and possible intervention will be performed through a brachial artery approach.

Fig 3.1a  Brachial artery identification.

Fig 3.1b  Microneedle accessing the brachial artery.

Fig 3.1c  Microwire.

Fig 3.1d  6F sheath going in the brachial artery.

Fig 3.1e  Brachial artery angiogram.

Video 3.1  Brachial artery access

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I  Vascular Access

Fig 3.1f  Artist’s illustration of brachial artery access.

Device List

Device Explanation

• Standard artery access. • Micropuncture kit. – Microneedle (21-gauge). – Microwire (0.010-inch diameter Cope Mandril, Cook Medical). – Microsheath (4F). • Intermediate sheath (if a large sheath is required (8F). • 30 cm J-wire to exchange the dilator for a larger sheath. • 4–6F femoral sheath.

To identify the brachial artery, in the antecubital fossa, palpate the biceps brachii tendon, the artery lies medial to this tendon. In the medial upper arm, palpate the inferior border of the biceps brachii tendon 5–10 cm proximal to the antecubital fossa. Advance the puncture needle (21-gauge) in a 45° angle until red blood is flowing out, then advance the J-wire and exchange for the sheath.

Tips, Tricks & Complication Avoidance • Strongly recommend ultrasound-guided artery access. • Always use fluoroscopy and observe the microwire and J-wire going into the brachial artery to prevent small arterial muscular branch cannulation and potential rupture. • Keep in mind that patients on antiplatelet or anticoagulation drugs could easily develop hematomas. Different from a hematoma

22

associated to femoral artery access, a hematoma around the brachial artery could easily cause a compartment syndrome and require surgical evacuation. • One benefit of brachial artery access is that patients are not required to be bed-bound for multiple hours.

4  Radial Artery Access Jason M. Davies

General Description Radial artery access has long been the preferred route for cardiac interventions because of ease of access as well as the low morbidity and mortality rates associated with this approach. Neurointerventionists are increasingly learning the techniques associated with radial artery access and converting to this route for the full spectrum of neurointerventional procedures. Avoiding difficult arch and groin anatomy, simplifying access to the posterior circulation, and increased patient mobility and satisfaction are among the significant benefits.

Indications Radial artery access is indicated for all neurointerventional procedures. The wrist can easily be used for procedures requiring a 6 French (F) access sheath and a sheathless 0.088-inch guide catheter can be inserted in most radial arteries for interventions requiring more robust access. Typically, staff will perform an Allen’s test to assess the patency of the palmar arch, but studies in the cardiac literature document low complication rates, even in the face of a negative (abnormal) Allen’s test.

Neuroendovascular Anatomy The radial artery is the main artery of the lateral aspect of the forearm. It is a continuation of the brachial artery after it bifurcates into the radial and ulnar arteries in the cubital fossa. In most people, the radial and ulnar arteries form the superficial palmar arch, which serves as an anastomotic supply to the hand. The Allen’s test is used to verify the patency of this arch by first compressing both ulnar and radial arteries and then documenting blood flow to the distal hand with the release of each artery.

Specific Technique and Key Steps A complete examination of the vascularity of the upper extremity should be performed, including palpating the radial and ulnar arteries, as well as checking for capillary refill in the ipsilateral hand. Many interventionists perform an Allen’s test to verify redundant supply to the hand. For ergonomic reasons, the right radial artery is commonly chosen for access (Fig. 4.1 and Video 4.1); however, the left radial artery may be preferable, particularly when selecting the left vertebral or subclavian artery for subsequent intervention. In left vertebral or subclavian artery procedures, often the left arm is simply draped across the patient’s abdomen to allow the interventionist to proceed from the usual position at the right of the patient. 1. After the wrist is prepared and draped, the radial artery is identified using a combination of palpation and ultrasound examination. 2. Once the puncture site has been identified, a local anesthetic is administered through a 30-gauge needle and a wheal is raised over the intended puncture site. 3. Using either single- or double-wall arterial puncture technique, a short sonographically guided opaque microneedle (i.e., 21-gauge micropuncture kit) is advanced at a 45° angle with the bevel facing up.

4. Once the return of brisk, pulsatile, bright red blood is established through the micropuncture needle, a microwire is advanced through the needle into the radial artery. If resistance is noted, the practitioner should stop and redirect the wire. Once the wire has been advanced several centimeters, fluoroscopy is used to confirm location. The needle is then removed, and a 5F or 6F slender sheath is inserted (Video 4.1). 5. Once arterial access has been established, we infuse an anticoagulant/spasmolytic radial cocktail consisting of 2,000 units of heparin and 10 mg of verapamil. 6. We routinely perform a radial artery angiographic run before proceeding with the case to assess the radial and brachial arteries for patency, stenosis, dissection, and possible extravasation (Video 4.1). 7. If larger gauge access is required, we measure the vessel on ultrasonography or angiography. A 3-mm vessel can easily support a 0.088-inch guide catheter. An exchange wire is advanced into the arch, and the guide sheath is removed. A sheathless guide catheter is advanced over an introducer into the radial artery.

Device Selection 1. 5–6F radial sheath placement requires the following: a. Radial microaccess kit (microneedle, microwire). b. 4–6F slender radial sheath. 2. 7–9F radial access requires the following: a. Radial microaccess kit (microneedle, microwire). b. 4–6F slender radial sheath.

Arterial Closure Radial artery punctures can be closed using an inflatable pressure bracelet placed over the puncture site. The band is left in place for 30–120 minutes depending on whether systemic heparinization was used during the procedure.

Pearls • The radial artery is prone to vasospasm. Ultrasound guidance is useful for avoiding vessel injury or spasm from multiple punctures. • The “cocktail” that includes lidocaine will help to prevent spasm during arterial access. • Drapes should be placed so as to allow access to both radial and ulnar arteries. If access is difficult with one artery or if vasospasm ensues, default to the other artery. • If resistance is encountered while advancing the microwire or needle wire, stop! When microwire resistance is encountered, it is an indication of advancing within a dissection flap or small caliber vessel. Advance the wire under fluoroscopy. Use a nitinol wire because they are longer and firmer. • Use long sheaths for vertebral, brachiocephalic, or subclavian stenosis because they will provide good support at the site of intervention without the need for a long guide catheter.

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I  Vascular Access

CASE 4.1 Radial Artery Access

Case Overview

Fig 4.1a  Microneedle accessing the radial artery.

Fig 4.1b  Microwire through the needle.

Fig 4.1c  5F Sheath.

Fig 4.1d  Redial artery angiography.

Video 4.1  Radial artery access

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4  Radial Artery Access

Fig 4.1e  Artist illustration of radial artery access.

Device List

Device Explanation

• Standard artery access. • Micropuncture kit. – Microneedle (21-gauge). – Microwire (0.010-inch diameter Cope Mandril, Cook Medical). – Microsheath (4F). • 4–6F femoral sheath.

Similar to brachial artery, radial artery access is an excellent alternative to femoral artery access for procedure in neuroendovascular surgery involving the anterior and posterior circulation. The technique involving radial artery access is similar to femoral artery or brachial access, the Seldinger technique is used. Ultrasound could be used to identify the artery; manual palpation and experience are sufficient.

Tips, Tricks & Complication Avoidance • Under direct fluoroscopy visualization, observe the microwire and J-wire going into the radial and brachial artery to prevent small arterial muscular branch cannulation and potential rupture. • The right arm is preferred, given its proximity to the clinician with the patient in the supine.

• In patients with subclavian stenosis or occlusion, the unaffected site is used. • Monitor for distal (hand) ischemia in all patients. • 10–20 mg of verapamil could be injected slowly through the radial sheath if there is evidence of vasospasm.

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5  Direct Carotid Artery Access Jason M. Davies

General Description Carotid artery access provides the most direct access to the anterior circulation but is fraught with potential hazards and should only be undertaken with extreme care and with proper weighing of the risks and benefits of the intended procedure. Carotid access by direct percutaneous puncture has the advantage of avoiding difficult arch anatomy and tortuosity in the proximal common carotid artery. The risks of direct puncture include dissection, stenosis, or breaking off calcified plaque that can directly cause stroke. For the interventionist, there is the additional hazard of increased radiation from close proximity to the X-ray source.

Indications Direct carotid access is indicated for anterior circulation procedures wherein aortic arch or common carotid anatomy prevents distal access routes.

Neuroendovascular Anatomy The common carotid artery is one of four paired afferents to the intracranial vasculature. The common carotid extends from the aortic arch (left) or brachiocephalic artery (right and bovine shared with left common carotid) and bifurcates into the internal and external carotid arteries, usually around the C3-4 vertebral level but with some variability. Patients with severe vasculopathies tend to accumulate atherosclerotic plaque at or near the bifurcation that can be heavily calcified.

Specific Technique and Key Steps Carotid artery puncture is best used for anterograde access to ipsilateral lesions. Carotid pulses are palpated to identify the target vessel starting approximately 2 cm above the clavicle and traced cephalad to approximately the level of the hyoid cartilage. Whereas access to distal sites can be undertaken with the patient under conscious sedation, carotid access is preferably performed under general anesthesia (Fig. 5.1 and Video 5.1). 1. After the neck is prepared and draped, the ultrasound unit is brought into the operative field to positively identify the carotid artery and to trace it as proximally as possible. 2. Once the puncture site has been identified, a local anesthetic is infused into the subcutaneous tissues. 3. Using a single-wall arterial puncture technique under ultrasound guidance, a sonographically opaque microneedle (i.e., 21-gauge micropuncture kit) is advanced into the carotid artery at a 45° angle with the bevel facing up.

26

4. Once brisk, pulsatile return of bright red blood is established through the micropuncture needle, a 0.010-inch microwire is advanced through the needle. If resistance is noted, the interventionist should stop and redirect the microwire. Once the wire has been advanced several centimeters, fluoroscopy is used to confirm location. The needle is removed, and an intermediate 4–5 French (F) maker sheath dilator is inserted. The introducer is thereafter removed, and a J-wire is inserted through the sheath into the internal carotid artery. The sheath is then exchanged for the procedural sheath of choice. For diagnostic procedures, typically a 5F sheath is chosen; however, the carotid artery can support up to a 9F sheath for intervention. The insertion of larger sheaths ranging from 8 to 9F often requires the use of an intermediate dilator and a stiffer wire to upsize to the final sheath size (Video 5.1). 5. We routinely perform a carotid artery angiographic run before proceeding with the case. We assess for patency, stenosis, dissection, and possible extravasation.

Device Selection 1. 5–6F radial sheath insertion requires the following: a. Microaccess kit (microneedle, microwire). b. 4–6F sheath. 2. 7–9F radial access requires the following: a. Microaccess kit (microneedle, microwire). b. 4–6F sheath. c. 7F dilator. d. 7–9F sheath.

Arterial Closure Carotid artery punctures should be closed with direct pressure. It is ill-advised to deploy a closure device because of the risk of embolization and stroke. Alternatively, a carotid cut-down can be performed either at the onset or at completion of the procedure and a figure 8 purse-string suture can be placed using a 6–0 nylon suture to close the arteriotomy directly.

Pearls • Access the carotid artery proximally to avoid disrupting bifurcation plaque during placement of the sheath. • The sheath behaves as the guide catheter, so sheath sizing should be planned, taking into account the intermediate or microsystems that will pass through it and not the traditional guide catheters. • Obtain a computed tomographic angiogram preoperatively to see the anatomy of the carotid artery, bifurcation level, presence of stenosis, calcifications, thrombus, etc.

5  Direct Carotid Artery Access

Case Overview

CASE 5.1 Direct Carotid Artery Access

• An 88-year-old female presented with acute ischemic stroke secondary to a left middle cerebral artery occlusion. Patient was taken for an emergent mechanical thrombectomy.

• Patient had calcified and tortuous aortic arch and great vessels preventing obtaining access into the left internal carotid artery (ICA). Multiple guide catheters and wires were used with no success. • Direct carotid access was then performed.

Fig 5.1a  Severe acute tortuosity of the internal carotid artery.

Fig 5.1b  21-gauge needle and microwire in common carotid artery.

Fig 5.1c  Holding needle and advancing microwire.

Fig 5.1d  Carotid angiogram ruling out dissection or vessel injury.

Fig 5.1e  Roadmap angiography for intracranial access with guide catheter.

Video 5.1  Direct carotid artery access

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I  Vascular Access

Fig 5.1f  Artist’s illustration of direct carotid artery access.

Device List

Device Explanation

• Standard artery access. • Micropuncture kit. – Microneedle (21-gauge). – Microwire (0.010-inch diameter Cope Mandril, Cook Medical). – Microsheath (4F). • 30 cm J-wire to exchange the dilator for a larger sheath. • 4–6F femoral sheath.

Direct carotid access could be obtained percutaneously with ultrasound guidance or through surgical exposure of the carotid artery. When the ICA is exposed, a puncture site is chosen and a pursestring suture is sewn down with a 6-O prolene. The puncture is made and the wire and catheters are inserted using the Seldinger technique. At the end of the procedure the purse-string suture is tied. An extra stitch might be necessary to achieve adequate hemostasis.

Tips, Tricks & Complication Avoidance • Cutdown methods for direct access add a layer of complexity to any endovascular case. Meticulous surgical technique with special attention to hemostasis and respect for natural tissue planes will prevent most access complications.

28

• If percutaneous puncture instead of cutdown is performed, we recommend to do a 2–3 mm skin stab incision to allow guide catheters into the artery with no resistance.

Part II



6 Diagnostic Cerebral Angiography

33

Diagnostic Procedures



7 Diagnostic Spinal Angiography

41



8 Diagnostic Cerebral Venography

45



9 Balloon Test Occlusion

48

10 Inferior Petrous Sinus Sampling

II

54

6  Diagnostic Cerebral Angiography Gary B. Rajah and Leonardo Rangel-Castilla

General Description A diagnostic cerebral angiogram, or any neuroendovascular intervention, starts with proper navigation of the aortic arch and craniocervical vessels. Recognition of the normal and variant anatomy is essential. Diagnostic cerebral angiograms provide information on vessel abnormalities, perfusion, and compensatory states. They provide the foundation for interventional neuroendovascular techniques, intra-arterial injection of chemotherapeutic, vasospastic, and other therapeutic agents, and Wada testing.

Indications Diagnostic cerebral angiography is indicated for patients with intracranial and extracranial cerebrovascular disorders. These include carotid and vertebral artery (VA) diseases, stroke related to large vessel occlusion, vasculitis, intracranial aneurysms, arteriovenous malformations and fistulas, hypervascular extra- and intracranial tumors, severe epistaxis, and other conditions. (Venous angiography will be covered in a separate chapter.)

Aortic Arch Anatomy The femoral artery is preferable for vascular access; however, radial and brachial access are also options (see radial and brachial access chapter for indications and details). The diagnostic catheter is advanced over a wire into the aortic arch. The abdominal and thoracic segments of the aorta have several branches, including the lumbar, renal, suprarenal, and intercostal arteries. Neurointerventionists must be aware of all of these branches to avoid inadvertent catheterization, accidental dissection, or rupture of these vessels. The aortic arch is the origin of three principal branches. From left to right, they are the left subclavian artery, the left common carotid artery (CCA), and the brachiocephalic trunk (i.e., innominate artery). Normal arch anatomy is found in 60%–70% of patients. The most common anatomical variations are the bovine arch, the left VA originating directly from the arch, and an aberrant right subclavian artery. As people age, the aortic arch becomes elongated, dilated, calcified, and less compliant. The origin of the great vessels is less straightforward and arises at more proximal levels. The classification scheme for aortic arch elongation (types 1–4) correlates with increased difficulty in great vessel cannulation and increased risk of complications. A bovine arch is the most common variation. In this variation, the left CCA and the brachiocephalic (innominate) artery share a common origin (“true bovine”), or most commonly, the left CCA arises from the innominate artery itself.

Specific Technique and Key Steps The neurointerventionist should understand the complexities of navigating the aortic arch anatomy (Fig. 6.1–6.3 and Video 6.1–6.3). Noninvasive studies of the aortic arch, such as computed tomography angiography (CTA) or magnetic resonance angiography, should be obtained prior to any neurointervention if possible. These studies will aid in understanding the aortic arch and great vessel anatomy. The results may provide pertinent information about anatomical variations and ostial atherosclerotic disease. 1. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, fluoroscopy is used to guide the diagnostic catheter over a curved wire

(0.035-inch angled Glidewire, Terumo) and into the aorta. It is important that adequate amounts of wire are extended beyond the catheter. If not, the wire becomes inflexible and may perforate vessels (Video 6.1–6.3). 2. For younger patients with straightforward anatomy, simple-curve catheters are a good option (Fig. 6.1, 6.3 and Video 6.1, 6.3). The Glidewire is advanced over the aortic arch and into the ascending aorta and is followed with the angled catheter. The catheter tip is torqued until it is in a vertical upright position. When the catheter is in proper position, there is a gentle backward withdrawal of the catheter until it “clicks” into the ostia of the great vessels. The wire is advanced into the great vessel (innominate artery, left common carotid artery, or left subclavian artery) and then the catheter is advanced over the wire. The same maneuver is repeated for the rest of the great vessels. Contrast material can be kept to a minimum by carefully observing the “click” while withdrawing the catheter, instead of “puffing” (a gentle and quick injection of 0.5–1 cc of contrast). A glide catheter (Glidecath, Terumo) can be advanced with a “puff”/push technique or over a wire. Roadmap-guided advancement of the catheter beyond the carotid bulb is preferred for most patients; however, purely anatomically guided advancement of the wire is also possible. 3. For older patients or patients with more complex anatomy, complex-curve catheters (e.g., Simmons 2 or 3, Terumo) are useful (Fig. 6.2 and Video 6.2). The distal curve of a complex catheter needs to be reformed (i.e., reconstituted) before catheterizing the great vessels. When this is achieved, the catheter is pushed until the aortic arch is crossed. To select the innominate artery, the catheter is gently pulled while contrast material is injected to reveal the ostia of the innominate artery. When the catheter is in the ostia of the vessel, a more robust pullback will allow the catheter to advance distally into the great vessel, breaking the curve of the Simmons catheter so it operates like a traditional straight catheter. To advance the catheter further, a roadmap should be obtained. Then, the Glidewire is advanced into the vessel followed by the catheter. This maneuver is repeated for the rest of the great vessels (Video 6.2). The removal of a Simmons catheter from a vessel should be performed similarly to its placement. Allow the catheter to herniate back into the arch and push it forward. Direct pulling on the catheter will require another reconstitution. 4. The reconstitution or reformation of the Simmons catheter is achieved in the following manner (Video 6.2). First, place the catheter into the arch over a wire and remove the wire past the curve. This is followed by a counterclockwise turn of the catheter to form an Omega sign. Next, apply gentle negative traction to place the Omega-shaped catheter under tension and move it to the least dilated area of the arch. Use firm, swift wire advancement to flip the catheter into its formed position. Finally, withdraw the wire and double flush the catheter. The Simmons can also be formed by “bouncing off” the aortic valve and via herniating out of the subclavian artery. 5. Catheterization of the bovine origin of the left CCA with a complex-curve catheter will require the “scissors maneuver” or “figure 8” maneuver. While the catheter tip is at the brachiocephalic artery, the catheter is torqued until it forms a figure 8. This will orient the catheter tip medially toward the origin of the left CCA. Then, gentle advancement of the catheter will retract the tip of the catheter to fall into the ostium of the left CCA. When the catheter tip is engaged, the catheter is pulled back and turned in the opposite direction to unfold the figure 8 loop and secure its position.

33

II  Diagnostic Procedures

Device Selection 1. The diagnostic catheter type is preselected based on the patient’s age. A single-curve angled catheter is used for patients under 50 years, and a complex-curve angled catheter is used for patients over 50 years. 1. Single-curve angled catheter: a. Angle, Glide (Terumo), Standard or Beacon tip (Cook). b. (used with 0.035-inch angled Glidewire). c. Continuous heparinized flush. 2. Complex-curve angled catheter: a. Simmons-2 catheter (Terumo). b. (used with 0.035-inch angled Glidewire). c. Continuous heparinized flush.

Pearls • A complete cerebral angiogram that includes all eight vessels (bilateral CCA, bilateral external carotid artery, bilateral internal carotid artery, bilateral VA) should be performed for all fistulas and hemorrhages of unknown etiology. Most other aneurysmal subarachnoid hemorrhage diagnostics can be completed with injections of the carotid arteries and the left VA with good flow down the contralateral VA to the posterior inferior cerebellar artery origin. If there is no flow, a right VA injection will be needed. (Tumors and other disorders will be discussed in other chapters.) • The most important complication to avoid is embolization from disruption of an unrecognized arch plaque and the associated risk of stroke. Preprocedural arch imaging with CTA demonstrates the presence of these plaques. Angiographic runs of the CCA before crossing the carotid bulb with a catheter also aid in preventing strokes. If large arch plaques are encountered, the procedure should be aborted. Presence of a large plaque is a contraindication for diagnostic cerebral angiography. If the angiogram is absolutely necessary, a dose of intravenous heparin (1,500–2,000 units) should be administered, and a simple straight catheter should be used if possible. • Simple-curve catheters are preferred for patients under the age of 50 who do not have atherosclerotic disease (Fig. 6.1, 6.3 and Video 6.1, 6.3).

34

• Complex-curve catheters are preferred for patients over the age of 50 who have atherosclerotic disease, proximal vessel tortuosity, or aortic arch variants (bovine arch). The distal curve of a complex catheter needs to be reformed (reconstituted) before catheterizing the great vessels (Fig. 6.3 and Video 6.3). • The most common problem encountered during diagnostic cerebral angiography is failure to catheterize the desired vessel secondary to arch tortuosity. If a standard-curve catheter does not work, a stiffer catheter is another option. Caution is advised with stiffer complex catheters because arches can become calcified and the catheter can dislodge the calcium, allowing it to embolize. Other diagnostic catheter options include the VTK catheter (Cook Medical) and Hinck Headhunter (Terumo). • The formation of intraluminal thrombus is a risk of cerebral angiography. We advocate the use of a continuous heparinized flush system during all diagnostic cerebral angiograms. • Patients with a history of collagen diseases (e.g., Marfan syndrome) are at a greater risk of vessel dissection even when the proper technique for catheter and wire manipulation is used. • Catheter-induced spasm must be differentiated from vessel injury or dissection; catheter spasm usually improves with the removal of the catheter. Verapamil can be administered when necessary. • A catheter should always be aspirated after removal of the wire and after connecting a new syringe if performing hand injections. This allows the removal of air and debris. We prefer to use the Copilot valve (Abbott Vascular) rather than a standard Tuohy valve (Cook Medical). If no blood returns during aspiration, the catheter is likely against a vessel wall and should be slowly withdrawn until blood is visible. If blood is not visible, assume the presence of thrombus inside the catheter. Do not inject! Withdraw the catheter and flush it. • Angled catheters should always be turned so the angle follows the vessel contour. This prevents spasm or injury. • Power injector runs are used for three-dimensional spins, and the frame rate is increased for high-flow lesions. Always check the power injector setting. Arch injections are performed at 600+ psi, and intracranial runs are typically performed at 300 psi. • Information about the patient’s renal status and contrast material allergies is always obtained so that the procedure can be performed safely.

6  Diagnostic Cerebral Angiography

CASE 6.1 Diagnostic Cerebral Angiogram

Case Overview

• A 46-year-old man presented with subacute onset of vertigo, dizziness, and headaches. • He has no significant past medical history.

• On computed tomography angiogram (CTA) he was found to have a vermian cerebellar arteriovenous malformation (AVM). • Patient needs a diagnostic cerebral angiogram for further evaluation.

Fig 6.1a  Axial CTA demonstrating a cerebellar vermian AVM.

Fig 6.1b  Coronal CTA demonstrating a cerebellar vermian AVM

Fig 6.1c  Sagittal CTA demonstrating a cerebellar vermian AVM.

Fig 6.1d  Artist’s illustration of diagnostic cerebral angiogram.

Video 6.1  Diagnostic cerebral angiography (simple curve catheter)

35

II  Diagnostic Procedures

Fig 6.1e Right common carotid angiogram with angle catheter.

Fig 6.1h Left vertebral artery angiogram with angle catheter.

Fig 6.1f Right internal carotid artery angiogram cranial view.

Fig 6.1g Left internal carotid artery angiogram cranial view.

Fig 6.1i Vertebral artery cerebral angiogram cranial view.

Device List

Device Explanation

• • • • • •

Diagnostic cerebral angiogram is a routine procedure in neuroendovascular surgery. Different techniques can be used. We routinely use a standard femoral approach with a 5F sheath. We favor an angle glide catheter; angle shape of the catheter allows easy access to internal and external carotid and vertebral arteries in young patients with minimal-to-no vessel tortuosity. Glide catheters are less traumatic to vessel’s endothelium with minimal risk of vasospasm or dissection, compared to nonglide catheters.

Standard diagnostic cerebral angiogram. Micropuncture kit for access. 5F femoral sheath. Angle glide catheter (Terumo). 0.035-inch angled Glidewire. Continue heparinized IV flush.

Tips, Tricks & Complication Avoidance • A complete diagnostic angiogram for AVM evaluation should include bilateral internal and external carotid arteries and bilateral vertebral arteries. • Simple-curve catheters are preferred for young patients with no or minimal vessel tortuosity. • We advocate the use of a continuous heparinized flush system during all diagnostic cerebral angiograms.

36

• To prevent catheter-induced emboli and possible strokes, a catheter should always be aspirated after removal of the wire and after connecting a new syringe if performing hand injections. This allows the removal of air and debris. • We advocate the use of the Copilot Valve (Abbott Vascular) rather than a standard Tuohy Valve (Cook Medical) to facilitate wire introduction and minimize air in the catheters.

6  Diagnostic Cerebral Angiography

Case Overview

CASE 6.2 Diagnostic Cerebral Angiogram (Complex Aortic Arch)

• A 79-year-old female presented with transient left arm and leg weakness. All symptoms had resolved at the time she was evaluated in the emergency room. She has a past medical history of hypertension, coronary artery disease, and carotid artery stenosis.

• Magnetic resonance imaging (MRI) demonstrate acute ischemic strokes on left middle cerebral territory. • Patient needs further neurovascular evaluation with a diagnostic cerebral angiogram.

Fig 6.2a  MRI with acute infarction.

Fig 6.2b  Artist’s illustration of diagnostic cerebral angiogram with Simmons 2 catheter.

Fig 6.2c  Simmons 2 catheter at the aortic arch.

Fig 6.2d  Simmons 2 catheter on an alpha (α) position.

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II  Diagnostic Procedures

Fig 6.2e  Simmons 2 catheter reconstituted.

Fig 6.2f  Right and left carotid artery angiogram showing severe bilateral stenosis.

Video 6.2  Diagnostic cerebral angiography (complex curve catheter)

Device List

Device Explanation

• • • •

Elder patients with vascular diseases have aortic arch with atherosclerosis, calcifications, type III arch, severe tortuosity, and noncompliant. Simmons 2 and Vitek catheter are excellent catheters to overcome these difficulties. Vitek catheter could also be used as a slit catheter for a larger guide catheter (e.g., Neuron MAX). Stiff or thick wires are often necessary (e.g., stiff 0.0035inch glide or 0.0038-inch). In this case, a Simmons 2 catheter was sufficient to navigate the aortic arch and get access into both common carotid arteries and left vertebral artery.

Standard diagnostic cerebral angiogram. Micropuncture kit for access. 5F femoral sheath. Simmons 2 glide catheter (Terumo), Vitek catheter (Cook Medical). • 0.035-inch angled Glidewire. • Continue heparinized IV flush.

Tips, Tricks & Complication Avoidance • Common complications related to complex arch navigation include: loss of access during intervention, injury to the great vessels, thromboembolism, and stroke. • We recommend the use of heparin during diagnostic procedures in cases of complex arch. • Prior to a diagnostic angiogram, assess the anatomy and atherosclerosis presence on a neck computed tomography angiography, especially in older patients.

38

• Use a buddy wire (V-18 0.0018-inch Stiff Glidewire) for additional support. • Balloon anchor technique is an effective alternative to ride catheters up from the arch.

6  Diagnostic Cerebral Angiography

Case Overview

CASE 6.3 Diagnostic Cerebral Angiogram (Pediatric)

• A 3-year-old female presented with progressive right hemiparesis and questionable seizures. • No past medical history.

• Magnetic resonance imaging (MRI) demonstrates a vascular malformation at the left frontoparietal area. • Further neurovascular evaluation with a diagnostic cerebral angiogram.

Fig 6.3a  MRI demonstrating the left frontoparietal vascular malformation.

Fig 6.3b  Artist’s illustration of pediatric diagnostic cerebral angiogram.

Fig 6.3c  4F angle catheter.

Fig 6.3d  Angle catheter in the right common carotid artery.

Video 6.3  Pediatric diagnostic cerebral angiography (simple curve catheter)

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II  Diagnostic Procedures

Fig 6.3e  Right common carotid artery angiogram.

Fig 6.3f  Right internal carotid artery angiogram cranial view.

Fig 6.3g  Left common carotid artery angiogram.

Fig 6.3h  Left internal carotid artery angiogram cranial view demonstrating the arteriovenous malformations.

Device List

Device Explanation

• • • • • •

Diagnostic cerebral angiogram are technically very similar to adults. Vessels are straight and easy to access. Femoral artery is routinely used as vascular access; the angiogram can be done with a femoral sheath or not. An angle glide catheter with a glide wire are preferred for pediatric patients because they are less traumatic than nonglide materials. Simple-curve catheters are preferred for the performance of selective cerebral angiography.

Standard diagnostic cerebral angiogram. Micropuncture kit for access. 4F femoral sheath. Angle glide catheter (Terumo). 0.035-inch angle Glidewire. Continue heparinized IV flush.

Tips, Tricks & Complication Avoidance • Keep track of the amount of contrast used in pediatric patients. • Limit radiation use as much as possible. • Diagnostic cerebral angiograms are performed under general anesthesia because of the lack of patient cooperation.

40

• Be gentle during contrast injection to avoid endothelial damage and vessel dissection.

7  Diagnostic Spinal Angiography Gary B. Rajah and Leonardo Rangel-Castilla

General Description A diagnostic spinal angiogram and any spinal neuroendovascular intervention start with proper navigation of the paired intersegmental (or radicular) arteries. Recognition of the normal and variant anatomy is essential. Diagnostic spinal angiograms provide information on vessel abnormalities such as spinal fistulas and spinal primary or metastatic tumor vascularity. The spinal angiogram is the foundation for interventional spinal neuroendovascular techniques such as tumor embolization and arteriovenous malformation (AVM) and fistula (AVF) identification and management.

Indications Diagnostic spinal angiography is indicated for patients with hypervascular spinal tumors. The tumors may be primary (e.g., hemangioblastoma) or metastatic (e.g., renal cell carcinoma). The angiogram may be used for evaluation in consideration of preoperative embolization before surgical removal of the tumor. It is also indicated for evaluation of patients in whom AVM or AVF is suspected.

Neuroendovascular Anatomy The femoral artery is preferable for arterial access for spinal angiograms and spinal interventions. When searching for spinal arteriovenous fistulae (sAVF), the entire neuroaxis must be imaged. The neurointerventionist should be familiar with the complete vascular anatomy pertinent to the central nervous system from sacrum to cranium.

Arterial System The lateral sacral vessels (extending from the internal iliac artery), median sacral artery, and paired intersegmental vessels from L5 to T2 must be identified. The ostia for the paired vessels emerge from the dorsal aorta only millimeters apart from one another, which is contrary to depictions in most schematic illustrations. The costocervical trunk, the supreme-most intercostal vessel, typically supplies the T1 vessels. Some variation near the aortic arch can be encountered with some ostia being absent and supplied by adjacent levels. The artery of Adamkiewicz (T10-L1; usually on the patient’s left side, also known as the greater anterior radiculomedullary artery) must be identified prior to embolization or surgical procedures because disruption of this vessel can result in spinal cord infarct because of its large supply of the thoracic cord via the anterior spinal artery. The cervical spine is supplied by paired vertebral vessels. The vessels ascend from the thyrocervical trunk (ascending cervical artery). The vertebral arteries produce radiculomedullary branches. The branches are usually found at C6 and C3 (cervical artery of enlargement) and feed the anterior spinal artery. Muscular branches can also supply the spinal arteries in diseased states. The anterior and paired posterior spinal arteries arise from the vertebral arteries (V4 segment) near the foramen magnum and anastomose at the lower end of spinal dura. The anterior spinal artery runs in the median fissure of the spinal cord and supplies most of the anterior spinal cord via perforators with the exception of the posterior columns that are supplied by the two posterior spinal arteries. There are 62 segmental arteries (31 on the left, 31 on the right). Each segmental artery corresponds with one spinal nerve root. Each radicular artery travels along with the spinal nerve and enters the

corresponding neural foramen under the pedicle. The radiculomedullary and radiculopial vessels stem from the paired segmental vessels near the neural foramen of each spine segment. The paired vessels continue as intercostal arteries and posterior musculocutaneous vessels. The radicular arteries are remnants of segmental vessels in embryology and contribute to the epidural arterial plexus. Identification of the radiculomedullary vessels is generally aided by the appearance of a midline spinal artery and an ascending shepherd’s crook-like orientation of the radicular vessel. The posterior radicular spinal arteries are typically somewhat tortuous and the posterior spinal arteries are off midline.

Venous System Paired veins drain the spinal cord. There is one anterior spinal vein, one posterior spinal vein, and two longitudinal veins that are located posteriorly and laterally. In the lumbar region, radicular veins drain back into spinal veins and into lumbar veins. In the thoracic region, radicular veins drain into hemiazygos (left) and azygos veins (right) and back to the vena cava system. Venous engorgement (hypertension) is a hallmark of sAVF at areas where radicular arteries enter the nerve root sleeve near radicular veins. Epidural venous drainage is responsible for draining the spinal cord and adjacent bony structures. The epidural veins are valveless and nondistensible. In the cervical region, the vertebral veins drain into the superior vena cava via the suboccipital venous system (Batson’s venous plexus). Batson’s plexus is the epidural venous plexus that has implications in the spread of metastatic disease or infections to the spine. Near the skull, the intracranial venous sinus may provide spinal drainage and, in states of venous hypertension, it can also appear enlarged. The spinal venous plexus connects with the clival plexus, marginal sinus, and the transverse and cavernous sinuses.

Specific Technique and Key Steps The neurointerventionist should understand the complexities of navigating spinal anatomy (Fig. 7.1 and Video 7.1). Spinal angiograms and interventions can become long and radiation/contrast intensive if not carefully planned. A table should be made to determine which levels and sides of the spine have been imaged to avoid missing a vessel or injecting a vessel more than once. Noninvasive imaging (e.g., magnetic resonance angiography [MRA]) of the spine should be obtained to aid in level localization and the number of segments that should be imaged. sAVF may require imaging of the entire neuroaxis. Tumor embolization may only require imaging of three segments above and below the level of the lesion. 1. After the femoral angiogram has been performed, the diagnostic catheter is advanced over a curved wire (0.035-inch angled Glidewire) into the aorta under fluoroscopic guidance. The wire must extend beyond the catheter. Otherwise, the wire becomes stiff and may perforate vessels. 2. A diagnostic catheter is advanced into the arch and each paired vessel is engaged along the dorsal aorta using anteroposterior fluoroscopy. Typically, a “puff technique” is utilized. Once the vessel is engaged within the ostium, a subtracted angiographic run is obtained (gentle hand injection to avoid kickback of the catheter and vessel injury). Caution is used to avoid entanglement in an ostium, which may cause spasm or rupture. Rather, disengage the ostium and then proceed. Some angiographers prefer to start in the cranial area and work down (Video 7.1).

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II  Diagnostic Procedures

Device Selection 1. The type of diagnostic spinal catheter is preselected based on the angiographer’s preference. A Cobra, Shetty, Mikaelsson, or Simmons 1 catheter is typically used. Catheterization of vertebral and thyrocervical vessels and costocervical trunks is performed similarly to catheterization for diagnostic cerebral angiograms. 2. Single-curve angled catheter for diagnostic angiography: a. Any of the above catheters. b. (used with a 0.035-inch angled Glidewire). c. Continuous heparinized flush.

•

•

Pearls • Eight-vessel (bilateral common carotid, bilateral external carotid, bilateral internal carotid, and bilateral vertebral arteries) cerebral angiography should be performed for all suspected spinal fistulas (i.e., in addition to angiography of the spinal and sacral vessels). • Remember to keep track of the contrast volume, spinal level, and radiation exposure! It is easy to inadvertently administer large amounts of contrast, miss or duplicate levels, and expose patients to large amounts of radiation. • One radicular artery may supply more than one or two spinal levels. • Glucagon can be given to halt bowel peristalsis and aid image clarity. • The patient’s respiration may have an effect on the quality of the angiogram. If the patient does not fully cooperate, general anesthesia with respiration pauses is recommended. • The diagnostic catheter should always be aspirated after removal of the wire and after connecting a new syringe when performing hand

42

•

•

•

injections. This removes air and debris. We prefer the use of the Copilot (Abbott Vascular) over a standard Tuohy valve. If no blood returns during aspiration, the catheter is likely against a wall and should be slowly withdrawn until blood is visible. If blood is not visible, assume the presence of thrombus inside the catheter. Do not inject! Withdraw the catheter and flush it. A microcatheter can be placed through the diagnostic catheter to allow interventions to be performed. Microinjection should be performed to assess for collaterals and radiculomedullary and pial vessels. Anatomic location of sAVF is not necessarily at the site of the lesion seen on imaging or at a site consistent with the patient’s examination findings (e.g., patients with lumbar radiculopathy and lumbar spinal cord edema can have a sAVF located at the thoracic spine level). If surgical resection of the lesion (e.g., AVM or AVF) is planned, coils can be inserted during diagnostic spinal angiography to mark sAVF levels for later X-ray identification during surgical removal. The identification of early venous drainage or venous engorgement on imaging studies is critical when searching for sAVF. Venous hypertension can be identified on imaging studies (e.g., MRA) by noting enlarged tortuous veins on the pial surface because the normal centrifugal drainage is disrupted by arterialized flow. Eventually, arterialized flow reverses or overcomes normal drainage and dilates the spinal veins. The spinal veins will try to relieve pressure via radiculomedullary veins. However, eventually the pressure will disrupt these veins, and the spinal vein will need to “recruit” more distant radicular veins to relieve pressure. We use the anterior spinal artery as a midline anatomical landmark. If the artery is displaced, pathology should be considered.

7  Diagnostic Spinal Angiography

Case Overview

CASE 7.1 Diagnostic Spinal Angiogram

• A 13-year-old female presented with progressive back and leg pain, and bilateral leg weakness. • No past medical history.

• Magnetic resonance imaging (MCI) demonstrates a thoracic spinal vascular malformation. • Further neurovascular evaluation with a diagnostic spinal angiogram is necessary.

Fig 7.1a  Thoracic MRI demonstrating the spinal vascular malformation.

Fig 7.1b  Artist’s illustration of diagnostic spinal angiogram.

Fig 7.1c  Left L2 radicular artery.

Fig 7.1d  Right L1 radicular.

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II  Diagnostic Procedures

Fig 7.1e  Left L3 and L4 radicular artery.

Fig 7.1f  Left T9 radicular artery feeding the arteriovenous fistula.

Video 7.1  Diagnostic spinal angiography (Cobra catheter)

Device List

Device Explanation

• • • • • •

An angle or a Cobra catheter are the two diagnostic catheters routinely used for spinal diagnostic angiography. Ostium of left and right radicular arteries are situated close to each other and can be found easily by gentle catheter micro-maneuvers. Pathological radicular arteries are commonly large enough to accommodate a 6F guide catheter in case of intervention.

Standard diagnostic cerebral angiogram. Micropuncture kit for access. 5F femoral sheath. Angle glide catheter (Terumo), Cobra catheter. 0.035-inch angle Glidewire. Continue heparinized IV flush.

Tips, Tricks & Complication Avoidance • Be conscious of the radiation time and amount of contrast used. • Most of the time, angiography is focused on the area of interest; however, a complete spinal angiogram should include vertebral, subclavian, thoracic, lumbar, iliac, and median sacral arteries. Not uncommon to find arterial supply to arteriovenous malformations or fistulas arising two or three levels above/below the level of interest.

44

• For better quality, have patients hold their breath while obtaining images. If the patient does not cooperate, consider general anesthesia with intermittent apneas as needed. Small or subtle vascular pathologies could be missed by not obtaining adequate quality images.

8  Diagnostic Cerebral Venography Jason M. Davies

General Description The venous side of the cerebrovascular system has garnered minimal attention in the past, but advances in the understanding of how it contributes to pathologies (e.g., stenosis in idiopathic intracranial hypertension, drainage in arteriovenous malformations) have increased our need to access and evaluate the venous system. For many cerebral pathologies, the venous system can be adequately visualized on delayed phases of arterial injections; however, when precise detail and pressures are required, diagnostic venography becomes a vital piece of the armamentarium.

Indications Diagnostic cerebral venography is most commonly used for direct evaluation of sinus stenosis, usually in patients with symptoms of idiopathic intracranial hypertension with evidence of stenotic segments on magnetic resonance venography. Diagnostic cerebral venography is also useful for assessing patency as smaller vessels and sinuses can be difficult to evaluate on late-phase arterial injections.

Neuroendovascular Anatomy The femoral vein accompanies and lies medial to the femoral artery and nerve within the femoral triangle. The femoral vein drains the lower extremities superiorly into the external iliac vein, which continues as the inferior vena cava before entering the heart. The superior vena cava extends superiorly from the heart, draining the upper extremities, head, and neck. It splits to form the paired subclavian veins that drain the internal jugular veins, which are the main venous outflow from the head. The venous sinus is the most common cerebral vein interrogated by venography. It extends from the superior sagittal sinus (SSS) to the torcula into paired transverse and sigmoid sinuses that ultimately drain into the internal jugular veins.

Specific Technique and Key Steps 1. After the groin is prepared and draped, the femoral artery pulse is palpated with the understanding that the vein should lie just medial to the palpated pulse. 2. Local anesthetic is infused into the skin and subcutaneous tissues in the groin region. 3. A microneedle (i.e., 21-gauge micropuncture kit) is connected to a saline-filled 10 mL syringe. Slight negative pressure is applied to the syringe as the needle is advanced into the femoral vein at a 45°angle with the bevel facing up (Fig. 8.1 and Video 8.1). 4. Once dark, nonpulsatile blood return is established through the micropuncture needle, a 0.010-inch microwire is advanced through the needle. Once the wire has been advanced several centimeters, fluoroscopy is used to confirm location. The needle is removed, and an intermediate 4–5 French (F) dilator is inserted. The introducer that comes with the dilator is thereafter removed, and a J-wire is inserted into the femoral vein. The dilator sheath is then exchanged for the procedural sheath of choice. For diagnostic procedures, typically a 5F sheath is chosen, but for venous sinus manometry, we typically use a 6F sheath for placement of a guide and microcatheter (Fig. 8.1 and Video 8.1). 5. Before proceeding with the case, we perform a femoral vein angiographic run to assess for patency, stenosis, dissection, and possible extravasation. 6. The diagnostic or guide catheter with obturator are advanced into the venous system over a 0.035-inch Glidewire. We preferentially cathe-

7.

8.

9.

10.

terize the right internal jugular vein given the relatively straight anatomy from the brachiocephalic vein to the superior vena cava. Venous valves can make navigation difficult. The tip of the catheter is brought close to the valve to provide additional support when crossing that valve (Video 8.1). For venous sinus manometry, we position the guide catheter near the sigmoid sinus and remove the obturator and 0.035-inch Glidewire and introduce the microcatheter and J-shaped wire. The microcatheter and J-shaped wire are sequentially advanced through the sigmoid, transverse, and SSSs to the anterior one-third to one-half of the SSS. The J-shaped wire is then withdrawn and contrast material is injected to evaluate the venous anatomy. To document venous pressures, connect a flushed pressure transducer directly to the hub of the microcatheter, pulling back the catheter to periodically capture pressures at set locations within the sinuses, including distal, mid- and proximal SSS, torcula, distal, mid-, and proximal transverse sinus, distal, mid-, and proximal sigmoid sinus, and the internal jugular vein. With a patent torcula, the contralateral side may then be accessed with the microcatheter and J-shaped wire by directing them across the torcula and measuring venous pressures in a retrograde fashion starting from the contralateral jugular vein and proceeding toward the torcula. Once pressures and venograms have been obtained, the guide or diagnostic catheter is carefully withdrawn.

Device Selection 1. 5–6F venous sheath insertion requires the following: a. Microaccess kit (microneedle, microwire). b. 5–6F sheath. 2. Diagnostic venography requires the following: a. Simmons 2 diagnostic catheter (Cordis ). b. 0.035-inch Glidewire. 3. Diagnostic venography with manometry requires the following: a. 6F soft diagnostic guide with Berenstein-type obturator. b. 0.035-inch Glidewire (Terumo). c. 0.035-inch microcatheter. d. 0.014-inch microwire (Synchro2, Stryker). e. Pressure transducer.

Vein Closure Femoral vein punctures should be closed with direct pressure. Given the low pressure relative to the arterial system, these typically only require a few minutes of direct pressure, and the risk of significant hematoma is relatively low.

Pearls • Refer to noninvasive imaging studies for procedural planning because there can be significant asymmetries at the level of the transverse and sigmoid sinuses. • A patent torcula can be used to study both left and right sides of the anatomy from a single approach. • A late-phase angiographic run from an arterial access catheter can provide a road map for accessing difficult venous anatomy. • Cortical veins can be easily perforated by an errant guidewire so care should be taken to make sure that the trajectory of the guidewire remains midline.

45

II  Diagnostic Procedures

Case Overview

46

CASE 8.1 Diagnostic Cerebral Venogram

• A 43-year-old obese female presented with progressive chronic and acute headaches and bilateral blurry vision. She was found to have bilateral papilledema; the rest of the neurological examination was normal. She has past medical history of hypertension and obesity. • Magnetic resonance imaging (MRI) was relevant for stenosis at the transverse sinus. Diagnostic and therapeutic lumbar puncture

demonstrated elevated intracranial pressure and patient’s symptoms improved after high volume tap. • Patient was diagnosed with idiopathic intracranial hypertension; further evaluation with a diagnostic cerebral venogram is necessary to assess the need for venous sinus stenting.

Fig 8.1a  MRI venogram suggesting stenosis of the right transverse sinus. .

Fig 8.1b  Artist’s illustration of diagnostic cerebral venogram.

Fig 8.1c  Cerebral venogram including superior sagittal, right transverse, and sigmoid sinuses.

Fig 8.1d  Lateral view cerebral venogram.

8  Diagnostic Cerebral Venography

Video 8.1  Diagnostic cerebral venography

Device List

Device Explanation

• • • • • •

An angle catheter is the diagnostic catheter routinely used for diagnostic cerebral venograms. The catheter is advanced over the 0.035-inch guidewire into each jugular vein. Valves could be difficult to cross, and a larger guide catheter or a 0.035-inch guidewire could be necessary for more support. A long intermediate catheter over the 0.035-inch guidewire is used in cases where access into the transverse or the superior sagittal sinus is needed.

Standard diagnostic cerebral venogram. Micropuncture kit for access. 5F femoral sheath. Angle glide catheter (Terumo). 0.035-inch angle Glidewire. Continue heparinized IV flush.

Tips, Tricks & Complication Avoidance • Passing the transverse sigmoid junction could be difficult at times. Use a stiff wire or large wire (0.038-inch wire) for more support. • Be cautious while advancing the wire through the transverse and the superior sagittal sinus, as it can inadvertently injure a cortical draining vein resulting in an intracranial hemorrhage.

• Always pay attention to the lateral projection to prevent inadvertent catheterization and perforation of the deep venous system and the cortical veins.

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9  Balloon Test Occlusion Jason M. Davies and Leonardo Rangel-Castilla

General Description The circle of Willis provides vital, if theoretical, redundancy for collateral cerebral blood supply. Balloon test occlusion (BTO) verifies the adequacy of collateral supply should the need arise to sacrifice or potentially compromise one of the major afferent vessels. It is a way of testing whether a permanent clinically significant neurologic deficit will result based on temporary occlusion of a particular vessel.

Indications

10.

BTO plays an important role in treatment planning for a variety of disease processes. Head and neck cancers that invade, encase, or compromise the carotid arteries can complicate resection. Foreknowledge that the vessel can be sacrificed, should the need arise, can simplify treatment strategies or enable backup plans. Large and complex aneurysms, particularly those near the skull base, are increasingly treated with flow diversion strategies, but vessel sacrifice remains a viable alternative if the interventionist can assure adequate intracranial flow through BTO.

11.

Neuroendovascular Anatomy The cervical internal carotid arteries (ICAs) are the most common target for BTO. To isolate flow to the intracranial compartment, the BTO is undertaken just distal to the carotid bifurcation. The external carotid artery can supply collateral or retrograde flow that can confuse results if this is not isolated during the test.

Specific Technique and Key Steps Carotid artery puncture is best used for anterograde access to ipsilateral lesions. Carotid pulses are palpated to identify the target vessel starting approximately 2 cm above the clavicle and traced cephalad to approximately the level of the hyoid cartilage. Whereas access to distal sites can be undertaken with the patient under conscious sedation, carotid access is preferably performed under general anesthesia (Fig. 5.1 and Video 5.1). 1. Distal access with a 6 or 7 French (F) sheath is obtained. 2. Using a diagnostic catheter of choice, a complete cerebral angiogram is performed to assure understanding of the underlying anatomy (Fig. 9.1, 9.2 and Video 9.1, 9,2). 3. The target vessel, usually a cervical ICA, is selected with the diagnostic catheter, at which point an exchange-length 0.035-inch guidewire is advanced into the target vessel with good distal purchase and the diagnostic catheter is exchanged out. 4. Depending on the nondiseased size of the vessel, a 6 or 7F balloon guide catheter is advanced into the target vessel and positioned distal to the bifurcation, thereby isolating the blood supply of interest. 5. The patient is given heparin, and therapeutic activated clotting time (ACT) is documented. 6. A baseline neurological examination is performed prior to balloon inflation and under conditions of normotension. 7. The balloon is inflated with a two-hand technique, with the practitioner puffing contrast material through the lumen of the catheter while gently inflating the balloon. The balloon is inflated only sufficiently to induce contrast stasis within the ICA or vertebral artery. Aggressive inflation can cause carotid dissection and should be avoided. The static contrast material will serve as an indicator of occlusion over the course of the test. 8. Every 3 minutes for a duration of 15 minutes, the practitioner should (1) perform fluoroscopy to evaluate for contrast status, keeping in mind that the contrast material is expected to slowly wash out with

48

9.

12.

the forward flow of heparinized saline through the flush; and (2) perform a neurological examination. If changes are observed in the neurological examination, the patient has demonstrated that the occluded circulation is essential and the test should be aborted (Video 9.1, 9,2). If no neurological changes are observed under normotensive conditions over the course of 15 minutes, the practitioner then starts an intravenous infusion of an antihypertensive agent (e.g., sodium nitroprusside), with the goal of dropping the mean arterial pressure (MAP) to 75% of the patient’s baseline. Once the goal MAP is obtained, the practitioner repeats frequent neurological examinations as per step 8. If the patient is able to maintain good neurological function throughout the period of hypotension, the patient is deemed to have passed the test. The balloon is deflated, and the catheter is withdrawn into the common carotid artery (Video 9.1, 9.2). Follow-up angiographic evaluations of both the cervical and intracranial arterial trees should be performed to ensure that no dissection and no thrombosis have occurred.

Device Selection 1. 6–7F arterial sheath insertion requires the following: a. Microaccess kit (microneedle, microwire). b. 6–7F sheath. 2. Diagnostic arteriography requires the following: a. Simmons 2 diagnostic catheter (Cordis). b. 0.035-inch Glidewire (Terumo). 3. BTO requires the following: a. 6 or 7F balloon guide catheter. b. 0.035-inch exchange-length Glidewire (Terumo). c. 3-mL syringe with hemostatic valve filled with 50% contrast material. d. Infusion of an antihypertensive agent (e.g., sodium nitroprusside).

Pearls • Use the most compliant balloon available. • Avoid overinflation and repeated inflation of balloons and do not manipulate a balloon while it is inflated. • Always inflate the balloon under fluoroscopic visualization (Video 9.1, 9.2). • Anticoagulate with heparin and maintain ACT above 300 seconds. • It is important to keep tight control of blood pressures throughout the duration of the examination because the natural tendency of the patient’s blood pressure is to increase to counteract decreased blood flow. Maintaining hypotensive pressure goals can be particularly difficult in younger patients with good cardiovascular function (Video 9.1, 9.2). • If a leak is detected around the balloon, the balloon should be reinflated and the schedule of neurological examinations should be restarted to avoid a false-negative test. • Patients with severe atherosclerotic disease may not be good candidates for BTO. As an alternative, a small compliant balloon microcatheter may be advanced into the petrous segment of the carotid artery if the burden of disease is less in that location. There is a greater risk of dissection within the petrous carotid, so care must be taken to avoid overinflation of the balloon. • Even though a patient may not demonstrate any deficit on an appropriately performed BTO, this does not guarantee that the same patient will not develop a deficit once the parent artery is definitively sacrificed. A false-negative rate up to 20% has been reported.

9  Balloon Test Occlusion

Case Overview

CASE 9.1 Balloon Test Occlusion

• A 56-year-old woman presented with a large skull base tumor, possible meningioma. Neurologically, the patient was grossly intact, with no evidence of any focal deficits. Her chief complaint was headaches and imbalance. She has no significant past medical history. • Magnetic resonance imaging (MRI) demonstrated a large skull base meningioma causing brainstem compression. The right internal carotid artery (ICA) and basilar artery were incased within the tumor.

• Patient requires a diagnostic cerebral angiogram for further evaluation, including balloon test occlusion (BTO) to assess collaterals in case the ICA needs to be sacrificed. The vascularity of the tumor should also be assessed for possible preoperative embolization.

Fig 9.1a  Brain MRI showing the large skull base tumor involving the ICA and vertebral artery.

Fig 9.1b  21-Artist’s illustration of balloon test occlusion.

Fig 9.1c  Left ICA showing no collateral flow to the right hemisphere.

Fig 9.1d  Vertebral artery showing no collateral flow to the anterior circulation.

Fig 9.1e  Right external carotid artery angiogram demonstrating the hypervascular skull base tumor.

Fig 9.1f  Balloon inflated occluding the right ICA.

49

II  Diagnostic Procedures

Fig 9.1g  10 minutes after initial balloon inflation. The balloon remains inflated and the ICA occluded.

Video 9.1  Balloon test occlusion (anterior circulation)

Fig 9.1h  Constantly check balloon and flow stasis.

Fig 9.1i  20 minutes after initial balloon inflation. The balloon remains inflated and the ICA occluded.

Device List

Device Explanation

• • • • • • •

To complete the preoperative evaluation of this large skull base tumor, diagnostic cerebral angiography with BTO is necessary. Before and after balloon inflation, contralateral ICA and vertebral cerebral angiography are done to assess for collaterals. The procedure can be done with a balloon-guide catheter (e.g., FlowGate) if available. A guide catheter (e.g., Neuron MAX) with a catheter (e.g., HyperForm, HyperGlide) can also be used. A compliant balloon is always preferred to a noncompliant balloon. Microcatheter balloons are more appropriate for intracranial vessels or posterior circulation. The balloon is always inflated under continuous X-ray, once stasis of contrast is noted distal to the balloon, the balloon is fully inflated. Check for continuous stasis with fluoroscopy every 5 minutes after balloon inflation to confirm flow arrest.

Standard diagnostic cerebral angiogram. Micropuncture kit for access. 8F femoral sheath. Angle glide catheter (Terumo). 0.035-inch angle Glidewire exchange length. 8F FlowGate balloon guide catheter (Stryker). Continue heparinized IV flush.

Tips, Tricks & Complication Avoidance • Even though a patient may not demonstrate any deficit on an appropriately performed BTO, this does not guarantee that the patient will not develop a deficit once the parent artery is sacrificed. There is a false-negative rate of up to 20%. • We suggest maintaining an activating coagulation time of more than 300 through the entire procedure. • We strongly recommend performing a simple (speech, motor, sensory) and detailed (neuropsychological test) neurological examination with hypotension challenge (drop blood pressure to one-third baseline mean arterial pressure).

50

• We prefer to check the neurological exam every 5 minutes for 15 minutes. If there is no change on the neurological exam after 15 minutes, we reduce the patient’s blood pressure to two-thirds of the baseline for another 15 minutes. • Any change on the neurological exam should be considered a failed BTO and the balloon should be deflated immediately. • Never manipulate the balloon while inflated.

9  Balloon Test Occlusion

Case Overview

CASE 9.2 Giant vertebral artery aneurysm: Balloon Test Occlusion

• A 48-year-old female was found to have a giant posterior fossa aneurysm during work up for headaches and neck pain. She had significant past medical history of hypertension and obesity. • Computed tomography and magnetic resonance imaging of the brain demonstrated a giant partially thrombosed aneurysm causing signif-

icant mass effect and compression of the brainstem (medulla). There was no hydrocephalus and no obvious brainstem edema. • Cerebral angiography confirmed a giant partially thrombosed right vertebral artery (VA) aneurysm. The basilar artery and the contralateral VA were not involved.

Fig 9.2a  Brain MRI showing the giant vertebral artery aneurysm

Fig 9.2b  Artist’s illustration giant vertebral artery aneurysm balloon test occlusion

Fig 9.2c  Giant right vertebral artery aneurysm

Fig 9.2d  Left vertebral artery supplying all posterior circulation branches

51

II  Diagnostic Procedures

Fig 9.2e  Right vertebral artery balloon test occlusion

Fig 9.2f  Left vertebral artery angiogram during balloon test occlusion

Fig 9.2g  Right vertebral artery parent vessel occlusion and aneurysm trapping

Video 9.2  Balloon test occlusion (posterior circulation)

52

9  Balloon Test Occlusion

Procedure • The patient underwent endovascular balloon test occlusion of the right vertebral artery and parent vessel occlusion. The procedure was performed under conscious sedation and through a right radial and femoral artery approach. 5000 Units of heparin were given to obtain and ACT more than 300.

Device List

Device Explanation

• Standard radial and femoral artery access – Micropunture kits (2) – 6 Fr sheaths (2) • 0.035-inch glidewire • Benchmark 071 guide catheter (Penumbra) • Diagnostic angle catheter (Cook) • 4x15mm Scepter C occlusion balloon catheter • 0.017-inch Excelsior SL10 microcatheter (Stryker) • 0.014-inch Synchro-2 microwire (Stryker) • Multiple intracranial coils • 6-Fr Angio-Seal percutaneous closure device

Under conscious sedation, accesses into the right radial and femoral arteries were obtained. A 071 guide catheter and an angle diagnostic catheter were positioned at the right and left VAs, respectively. A semi compliant balloon was positioned at the right VA, just proximal to the giant aneurysm. The balloon was inflated occluding the right VA occlusion and confirmed with VA angiography. Over a period of 20 min and under hypotension (mean arterial pressure 65 mm/Hg) the patient remained neurological intact and passed the BTO. The right VA aneurysms was then trapped and the aneurysm obliterated.

Tips, Tricks & Complication Avoidance • Parent vessel occlusion remains a viable and durable option in the treatment of selected intracranial aneurysms. The most common aneurysms treated with parent vessel occlusion include vertebral artery dissecting aneurysm, large or giant aneurysms, and small distal aneurysms.

• For large vessel BTO, we strongly recommend performing simple (speech, motor, sensory) and detailed (neuropsychological test) neurological examination with hypotension challenge (drop blood pressure to one-third baseline mean arterial pressure), and have an ACT between 250-300.

53

10  Inferior Petrous Sinus Sampling Enrico Giordan, Giuseppe Lanzino, and Leonardo Rangel-Castilla

General Description Inferior petrosal sinus (IPS) sampling is an endovascular procedure used for the evaluation of patients with Cushing’s disease (CD). In the setting of hypercortisolemia, the procedure is performed to differentiate a pituitary from an ectopic source of the adrenocorticotropic hormone (ACTH). It can also be used to localize a patient’s pituitary microadenoma (i.e., midline or right or left of midline) with an average accuracy of 78% (range 50%–90%). ACTH levels obtained from venous drainage in proximity to the pituitary gland are compared to peripheral blood levels before and after corticotropin-releasing hormone (CRH) stimulation. ACTH is expected to be found at a higher concentration close to the gland with respect to distant location. Therefore, an ACTH gradient indicates pituitary CD, whereas the absence suggests ectopic CD. In the setting of CD, pituitary release of ACTH is increased in response to intravenous administration of CRH. ACTH is released from the anterior pituitary gland; it drains into the cavernous sinus and jugular venous system via the IPS. The IPS sampling procedure was introduced in 1977 in a unilateral form and was adopted for diagnostic evaluation of Cushing’s syndrome in 1991. Currently, bilateral IPS sampling is the closest procedure to a reference standard for differential diagnosis of CD and is more accurate than clinical, biochemical, and imaging analyses, with a sensitivity and specificity of 88%–100% and 67%–100%, respectively, that increase to 96%–100%, respectively, after CRH stimulation. Successful bilateral sampling is usually achieved in more than 90% of cases with false-negative rates ranging from 1% to 10%.

Indications Bilateral IPS sampling should be reserved for • Patients with clinical and biochemical evidence of CD and negative or equivocal magnetic resonance imaging (MRI) findings (no discrete pituitary lesion on MRI). • Patients with equivocal responses to hormone testing or in cases of discrepancies between biochemistry and imaging findings. • Persistence of Cushing’s syndrome after previous unsuccessful pituitary surgery, to confirm the CD diagnosis. • Patients with an ACTH or cortisol response to the CRH test not consistent with CD, independently from the response to a high-dose dexamethasone suppression test, unless the MRI finding shows clear evidence of pituitary adenoma. Bilateral IPS sampling should not be performed in the following circumstances: • A positive response to the CRH test, especially in the case of a consistent response to the dexamethasone suppression test, even in the absence of MRI evidence of pituitary adenoma. • Bleeding diathesis or disorders. • Allergy to contrast material.

Neuroendovascular Anatomy Understanding the venous anatomy is crucial to the success of the procedure. Blood from the anterior lobe of the pituitary gland flows through the hypophyseal veins into a network of veins overlying the anterior pituitary surface, which drains laterally into the cavernous sinuses, and from here into the IPSs, which course posteriorly and caudally passes through the anterior jugular foramen, at the skull base. The cavernous sinuses are lateral to the pituitary fossa and are interconnected by the

54

anterior and posterior intercavernous sinuses, which run in front of and behind the pituitary gland, by the inferior intercavernous sinus coursing along the sellar floor between the anterior and posterior pituitary lobes, and by the basilar plexus, which is located along the dorsum sellae. As the IPS courses through the dura, it receives tributaries from the dura, pons, medulla, internal auditory meatus, and the anterior condylar vein (ACV), which communicates with the plexus surrounding the 12th cranial nerve in the hypoglossal canal. Pituitary venous drainage is normally unilateral, thus allowing the lateralization of ACTH-secreting adenomas through bilateral IPS sampling. Approximately 75% of patients have large, bilaterally symmetrical IPSs; 18% have asymmetrical IPSs with one smaller than the contralateral; and in 7%, the petrosal sinuses are bilaterally small. The IPS typically joins the internal jugular vein at the level of the inferior margin of the jugular foramen, approximately 6 mm below its entry into the foramen, although in some cases, the junction may be extracranial or intracranial or it may drain directly into the sigmoid sinus. Anatomic variants are not uncommon and can cause an alternative venous drainage. They are categorized into four groups. In type I (45%), the IPS drains directly into the internal jugular bulb with absent or nearly absent communication with the ACV. In type II (24%), the IPS anastomoses with the ACV before draining into the internal jugular vein. In type III (24%), the IPS drains into the internal jugular vein as a plexus of veins rather than as a single vein. In type IV, the IPS drains solely or predominantly into the vertebral venous plexus by way of the ACV, without a connection between the IPS and the jugular vein. This configuration is present in 1%–7% of patients. In the case of hypoplastic IPS, bilateral IPS sampling yields false-negative results in approximatively 1% of cases.

Procedural Preparation The procedure, including ACTH sampling after CRH stimulation, usually lasts for 60–90 min and is performed under conscious sedation. The suppression of normal corticotrophs by long-standing hypercortisolemia is crucial for the diagnostic accuracy of bilateral IPS sampling, because it ensures that any ACTH measured is secreted by tumor tissue (pituitary or ectopic). As ACTH secretion is intermittent and blood samples obtained between two ACTH secretory episodes might result in a false-negative ratio (central vs. peripheral ACTH blood concentration); the procedure is performed under CRH stimulation to increase diagnostic sensitivity. We routinely administer systemic heparin to an activated coagulation time of 250–300 s.

Specific Technique and Key Steps 1. The patient is placed supine on the angiography suite table, and the right and left inguinal regions are prepared and draped in a sterile manner. The skin and subcutaneous tissue over the puncture site are infiltrated with local anesthesia. 2. A 5 French (F) sheath is placed in each of the common femoral veins (Fig. 10.1 and Video 10.1). 3. Intravenous heparin (3,000–5,000 units) is administered to avoid IPS and cavernous sinus thrombosis along with placing the catheter and sheaths on a continuous heparinized saline drip to avoid catheter thrombosis. Be aware that leaving catheters in situ within both IPSs may increase the risk of a brainstem insult compared to sequential IPS sampling with immediate removal of catheters. Postoperative deep venous thrombosis and pulmonary embolism can be avoided with prophylactic anticoagulation.

10  Inferior Petrous Sinus Sampling 4.

5. 6.

7.

8. 9.

10.

11.

Two 5F diagnostic guide catheters are used to selectively catheterize the right and left internal jugular veins, and a venogram is performed (Fig. 10.1 and Video 10.1). At the C1-2 vertebral level, the catheters and wires are carefully directed medially and anteriorly to access the IPS (Video 10.1). A 0.027-inch microcatheter is used to selectively catheterize the right IPS. Once an IPS is catheterized, a venogram is performed to visualize the ipsilateral IPS, superior petrosal sinus, cavernous sinus, and contralateral IPS. At this point, roadmap technique helps to guide the contralateral wire and catheter. Similar microcatheterization is performed on the left IPS. Digital subtraction venography is performed through each microcatheter to confirm catheter location (Video 10.1). Simultaneous sampling is performed according to this protocol: blood samples from the IPS are obtained 1 and 5 min before CRH stimulation; blood samples from the IPS are obtained from the IPS 2, 5, and 10 min after CRH stimulation; and samples from a peripheral vein are obtained 30, 45, and 60 min after CRH stimulation. Before each sample is drawn, the catheters are aspirated and saline-diluted blood is discarded. Once all samples are obtained, a venogram is performed before removing the catheters to exclude iatrogenic injury to the veins or sinus or thrombosis (Video 10.1). After blood sampling, catheters and sheaths are removed and compression of the inguinal regions is performed for 10 min. Percutaneous closure devices (e.g., Mynx, Cardinal Health) or AngioSeal, Terumo) are not indicated for femoral vein closure. After the procedure, the patient is observed under strict bed rest for 4–6 h before being discharged.

Device Selection In the authors’ and editors’ practice, the following are common setups and devices used for IPS sampling.

• • • • • •

5F sheath. 5F diagnostic catheter. 0.035-inch angled Glidewire (Marksman, Medtronic; Velocity, Penumbra). 0.027-inch microcatheters. 0.014-inch microwire (Synchro 2, Stryker). Continuous heparinized flush.

Pearls •

•

•

•

•

• •

Catheterization of the IPS is technically demanding, and even an experienced interventionist may fail in up to 15% to 20% of cases. When bilateral IPS sampling through a femoral approach is not feasible because of aberrant anatomy, an inferior vena cava filter, or thrombosis, direct jugular vein access should be considered. Digital subtraction venography should always be performed bilaterally, before and after the sampling, allowing one to confirm the correct positioning of the catheters. If an anastomosis between the internal jugular vein and IPS is missing, the catheters can be placed at the C1-2 vertebral level for sampling. However, the sampling at this level may lead to false results secondary to transverse or sigmoid sinus contamination. A catheter inserted into a hypoplastic or plexiform sinus might appear appropriately positioned but can simultaneously cause altered venous drainage and obstruction. In the case of an atrophic or plexiform IPS, direct sampling from the cavernous sinus might compensate for the problem. Complete venography of the basilar sinuses might be included within the interpretation of venous sampling data, particularly in the context of an intersinus gradient of ACTH determination for localization of the pituitary adenoma.

55

II  Diagnostic Procedures

Case Overview

56

CASE 10.1 Petrosal Sinus Sampling

• A 57-year-old female presented with signs and symptoms of possible Cushing’s disease. She has a past medical history of hypertension, diabetes, and central obesity. Laboratory results were consistent with Cushing’s disease. • Magnetic resonance imaging (MRI) demonstrated a small enhancing pituitary tumor.

• Further evaluation requires inferior petrosal sinus (IPS) sampling with a corticotropin-releasing hormone (CRH) challenge to assess diagnosis and laterality.

Fig 10.1a  MRI demonstrating a possible 3-mm pituitary microadenoma. .

Fig 10.1b  Artist’s illustration of bilateral inferior petrosal sinus sampling.

Fig 10.1c  Right inferior petrosal sinus.

Fig 10.1d  Left inferior petrosal sinus.

10  Inferior Petrous Sinus Sampling

Fig 10.1e  Deep venous draining system.

Fig 10.1f  Bilateral IPS catheterization.

Table 10.1 IPS sampling results

Timing

Left IPS

Right IPS

ACTH - 5 min

667

16

ACTH - 1 min

42

48

ACTH - 2 min

4,244

291

ACTH - 5 min

3,011

481

ACTH - 10 min

1,657

169

Video 10.1  Petrosal sinus sampling

Device List

Device Explanation

• • • • • • • •

An angle is the diagnostic catheters routinely used for diagnostic cerebral venograms. A large diameter microcatheter (0.021-inch microcatheter) is necessary to draw blood samples easily. Attention is paid to ensure the microcatheter tip remains in the IPS and does not enter the cavernous sinus. Venous sampling protocol: – Blood is obtained from the femoral vein sheath and from both microcatheters simultaneously. – First sample is obtained 5 min prior to CRH administration. – Second sample at the time the CRH is administered. – Third sample at 3 min after the CRH is administered. – Fourth sample at 5 min after the CRH is administered. – Third sample at 10 min after the CRH is administered. .

Standard diagnostic cerebral venogram. Micropuncture kit for access (2). 5F femoral sheath (2). Angle catheter (Terumo) (2). 0.035-inch angle Glidewire. 0.021-inch microcatheter (Headway DUO, MicroVention). 0.014-inch microwire (Synchro 2 wire, Stryker). Continue heparinized IV flush (2).

Tips, Tricks & Complication Avoidance • The procedure is worthless without accurate timing of the blood draws and accurate handling of the blood samples. • We prefer to first access the right IPS because of a more direct pathway. • Once one IPS is catheterized, a venogram is performed. This will yield better visualization of the contralateral IPS and provide a roadmap for appropriate catheterization.

• If any of the IPS cannot be identified, obtain arterial access and performed a carotid angiogram. The venous phase of this may help identify the insertion of the IPS into the draining venous system.

57

Part III Extracranial Vessel Angioplasty/Stenting

III

11 Carotid Artery Stenting with Distal Protection

61

12 Carotid Artery Stenting with Proximal Protection (Flow Arrest)

81

13 Carotid Artery Stenting under Flow Reversal

97

14 Angioplasty with or Without Stenting for In-Stent Restenosis or Recurrent Stenosis

102

15 Vertebral Artery Stenting

110

16 Venous Sinus Stenting

114

11  Carotid Artery Stenting with Distal Protection Gary B. Rajah and Leonardo Rangel-Castilla

General Description Carotid artery revascularization is an effective modality of stroke prevention in selected patients with carotid stenosis. Carotid endarterectomy (CEA) is a well-established surgical method of revascularization. With the advancement of endovascular techniques and technology, protected carotid artery stenting (CAS) has become a viable alternative to CEA. There are different types of embolic protection from distal devices, such as filters and balloons, and proximal devices, such as balloon guide catheters and the Gore Flow Reversal System (Gore). Newer hybrid endovascular–surgical devices are also available for direct carotid artery access. Furthermore, CAS can also be utilized in the setting of acute ischemic stroke for tandem (extracranial and intracranial vessel occlusion) lesions.

Evidence for CAS Performed with Distal Protection • The Stenting and Angioplasty with Protection in Patients with High Risk for Endarterectomy (SAPPHIRE) study compared protected CAS to CEA in patients at high risk for surgical complications with > 50% symptomatic stenosis or > 80% asymptomatic stenosis. The study findings showed that CAS was an effective treatment option for this patient population. The 1-year rate of ipsilateral stroke or procedure-related or vascular death was 12.2% for CAS and 20.1% for CEA. • The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) randomized 2,502 patients with symptomatic or asymptomatic carotid stenosis (>50% stenosis on angiography or > 70% on ultrasonography) to CEA or protected CAS. The investigators found no significant difference in the rates of periprocedural stroke, myocardial infarction, or death in the treatment groups. • The asymptomatic carotid trial (ACT) randomized 1,453 patients with asymptomatic severe (70%–99%) stenosis and found that protected CAS was noninferior to CEA with 30-day stroke or death rates of 3.8% versus 3.4%, respectively.

Indications CES is indicated for patients with symptomatic internal carotid ar­ tery (ICA) stenosis > 70% or asymptomatic ICA stenosis >80%. Other indications include the inability to tolerate general anesthesia during CEA, contralateral carotid occlusion or laryngeal nerve palsy, previous neck surgery or radiation therapy, restenosis after CEA, and poor neck mobility. CAS is also used for treatment of dissections and cases of acute stroke with tandem occlusions, as stated earlier. Medicare has specific requirements for CAS reimbursement.

Neuroendovascular Anatomy The ICA normally originates from the common carotid artery (CCA) at the C3-4 or C4-5 level of the cervical spine. The artery may occur as low as T2 and as high as C1. The ICA is the largest of the two CCA branches. The carotid bulb (or sinus) forms a focal dilation and is the most proximal aspect of the cervical ICA. The diameter of the bulb is approximately 7.5 mm, compared to the CCA diameter of 7.0 mm and the ICA diameter of 4.7 mm distal to the bulb. The proximal ICA initially lays posterolateral to the external ca­ rotid artery (ECA), then courses medial to the ECA as it courses upward. The cervical ICA has no branches. Tortuosity and kinking or looping of the ICA occasionally occur, especially in older patients. Coiling or complete looping

of the ICA occurs in 5%–15% of patients. One must always be vigilant for ab­ errant anatomy (i.e., proatlantal persistent vessels) that could be disrupted during stenting, resulting in posterior circulation stroke.

Periprocedural Medications Dual antiplatelet therapy with aspirin (325 mg daily) and clopidogrel (75 mg daily) is prescribed for the prevention of platelet aggregation on the stent with resultant formation of an intraluminal thrombus during or after the stenting procedure. The regimen is started 5–7 days before the procedure for elective procedures. If that is not possible, a loading dose of aspirin (650 mg) and clopidogrel (600 mg) should be given early on the day of the procedure, followed by daily doses of aspirin (325 mg) and clopidogrel (75 mg). Dual antiplatelet therapy is maintained for 3 months after stent placement, at which point the clopidogrel is discontinued and the aspirin is continued indefinitely. Aspirin and clopidogrel serum responses should be monitored and therapeutic. Patients can be nonresponsive or allergic to clopidogrel. An alternative is ticagrelor (60 mg twice daily). Intraprocedural thrombus formation is always a risk and systemic heparinization is administered during the procedure because of the risk of intraprocedural thrombus formation. A weight-based intravenous bolus of heparin aimed at an activated coagulation time of 250–300 seconds may limit thromboembolic complications. Administration of the heparin before crossing the stenotic lesion may limit thrombus formation on devices positioned within the ICA. For acute thrombus formation during the procedure, a glycoprotein IIb/IIIa inhibitor (e.g., eptifibatide) is utilized. Hemodynamic instability sometimes occurs during carotid stenting and balloon angioplasty. Bradycardia, asystole, and hypotension are the most common events. During the procedure, asking the patient to perform a Valsalva maneuver (i.e., to cough) will usually reverse bradycardia. A good practice is to have a vasopressor (e.g., dopamine or phenylephrine) avail­ able, as well as atropine. We typically perform CAS with the patient in an awake state (i.e., conscious sedation) for accurate neurological assessment.

Specific Technique and Key Steps Several clinical trials have demonstrated the efficacy of embolic protection devices in preventing intraprocedural ischemic complications. Using a distal embolic protection device, the key steps for CAS are as follows (Fig. 11.1-11.6, Video 11.1-11.6). 1. A 6 or 8 French (F) sheath is inserted in the femoral artery. 2. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a curved wire (0.035-inch angled Glidewire, Terumo) into the aorta. This maneuver is completed under fluoro­ scopic guidance. 3. Depending on the arch anatomy, the guide catheter can be brought up directly over a 0.035-inch angled Glidewire or advanced over a 4–5F intermediate diagnostic catheter, such as a Vitek (Cook Med­ ical) or Berenstein catheter (Cook Medical). Utmost care should be taken to prevent the wire, catheter, or guide from crossing the stenotic lesion. 4. Cerebral angiography is performed to obtain a baseline set of images of the intracranial vasculature. 5. Cervical carotid angiography with magnified working views of the carotid artery is obtained. Measurements of the degree of stenosis, length of stenosis, and diameters of the CCA and distal ICA are obtained for proper sizing of the stent. 6. Selection of the stent (Video 11.1-11.6):

61

III  Extracranial Vessel Angioplasty/Stenting

7.

8.

9.

10.

11.

12. 13.

a. Closed-cell stent—Xact (Abbott Vascular) or Wallstent (Boston Scientific)—usually used for acute symptomatic ICA stenosis or with other high-risk feature (hemorrhage or plaque morphology (ulcerated). b. Open-cell stent—Acculink (Abbott Vascular) —for tortuous anatomy. c. High-radial-force stent—for a heavily calcified lesion. d. Tapered stent—for discrepancy between the diameters of the ICA and CCA. The distal embolic protection device is navigated through the stenosis up to the upper cervical ICA and deployed under fluoroscopy. The steps for deployment are different for different devices but usually involve unsheathing the device (Video 11.1-11.6). Once the filter has been deployed and under roadmapping guidance, the stent is advanced over the area of stenosis and deployed. Typi­ cally, a rapid exchange system is utilized. The stent is sized 1–2 mm beyond the diameter of the CCA (Video 11.1-11.6). Cervical carotid angiography is performed to assess post-stenting residual stenosis and the need for balloon angioplasty (Video 11.111.6). A noncompliant balloon is used to perform angioplasty poststent placement. The balloon is undersized by 1 mm less than the diameter of the ICA (Video 11.1-11.6). Intravascular ultrasound can be used to identify residual stenosis, re­ sidual debris within the lumen, or stent apposition to the artery wall (Fig.11.1, Video 11.1). The distal protection device is captured and removed utilizing a separate distal capture device (catheter). A final (i.e., control) cerebral angiogram is always recommended to assess for smooth synchronized perfusion, looking specifically for delayed capillary filling or other larger occlusion (vessel dropout).

Device Selection In the authors’ and editors’ practice, the following are the common set-ups and devices used for CAS with distal protection: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy XB catheter or Cook Shuttle, Cook Medical). • 0.035-inch angled Glidewire. • Intermediate 5F-diagnostic catheter (Vitek). • Distal protection device (i.e., Emboshield NAV6 embolic protection device, Abbott or Gore). • Carotid stent (closed-cell Wallstent, Boston Scientific), (Mesh Covered Stent [Fig. 11.2, Video 11.2]).

62

• Noncompliant balloon. • Distal capture device (protection device manufacturer-specific). • Continuous heparinized flush.

Pearls • One of the most technically challenging portions of CAS is placement of the guide catheter. The amount of purchase of a guide catheter in a stenotic carotid artery lesion is limited and often in the setting of difficult anatomy (bovine arch, dilated and calcified arch, and/ or tortuous great vessels). A stiff, robust guide catheter (like those previously mentioned) is necessary so the catheter does not herni­ ate downward into the aortic arch when the stent is advanced into position. • For crossing the lesion, a steerable 0.014-inch microwire is used. Some angulation of the tip of the microwire is recommended for ease of guidance through the area of stenosis. Microwire shaping conforms to the unique anatomy of the patient’s lesion. • Looped or tortuous anatomy of the ICA may complicate navigation into the distal cervical ICA. The wire is passed to a point in the cervical ICA that enables passage of the stent safely beyond the stenosis. A stiffer wire might be required. Consideration is given to the use of a proximal protection guide catheter (MoMa guide cath­ eter) in this scenario. • For stent placement, we recommend selecting an osseous landmark (i.e., a cervical vertebrae) to be the distal landing site of the stent. Without such a landmark, the roadmap may be unreliable because of vessel deformation that occurs with positioning of the stent or guide catheter or because of patient motion. • If the stent is not easily passed through the lesion over the microwire, pre-stent angioplasty is performed with an undersized balloon to prevent plaque rupture (Fig. 11.3, 11.4, Video 11.3, 11.4). • For closed-cells stents, a malpositioned stent may be recaptured if partially deployed (up to 80% for most closed-cells stents). Otherwise, various telescoping stents may be required. • During recapture of the distal protection device, difficulty may be encountered when navigating the retrieval sheath through the stent. This is particularly problematic if the interventionist is using an open-cell stent. The patient may be asked to turn his or her head in either direction as passage of the retrieval catheter through the stent is attempted again. Careful monitoring for stent dislodgement under continuous fluoroscopy is necessary until the protection device has been withdrawn.

11  Carotid Artery Stenting with Distal Protection

Case Overview

CASE 11.1 Internal Carotid Artery Stenting and Angioplasty Use of Intravascular Ultrasound

• A 71-year-old male presented with transient numbness and tingling on the left upper and lower extremities. His past medical history was relevant for hypertension, diabetes mellitus, hypercholesterolemia, coronary artery disease, and previous left carotid artery stenosis treated with stenting and angioplasty. Patient is taking aspirin and Clopidogrel for his coronary disease.

• Carotid Doppler ultrasound and computed tomography angiography demonstrated severe stenosis (90%) of the right internal carotid artery (ICA). Carotid Doppler ultrasound showed velocities of 360/160 cm/s.

Fig 11.1a  Anteroposterior and lateral cervical angiography showing severe stenosis of the ICA.

Fig 11.1b  Artist’s illustration of carotid artery stenting and angioplasty.

Fig 11.1c  Embolic protection filter device deployed at C1 level.

Fig 11.1d  Balloon angioplasty. Observe the “waist” at the middle of the balloon (severe carotid stenosis).

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Fig 11.1e  Carotid stent deployment.

Fig 11.1f  Intravascular ultrasound demonstrating adequate stent apposition with significant improvement of the stenosis

Fig 11.1g  Embolic protection filter captured.

Fig 11.1h  Successful ICA revascularization.

11  Carotid Artery Stenting with Distal Protection Video 11.1  Internal carotid artery stenting angioplasty assessed with intravascular ultrasound

Procedure • The patient underwent right carotid artery angioplasty and stenting with a distal filter protection device. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook Shuttle guide catheter (Cook Medical). • 0.035-inch Glidewire (Terumo). • NAV6 Distal filter device (Abbott). • Aviator 4.5 x 30 mm angioplasty balloon (Abbott). • Xact stent 6 x 8 x 30 mm (Abbott Vascular). • Intravascular ultrasound (IVUS). • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

This is a case of a patient with symptomatic carotid artery stenosis. The anatomy of the carotid artery is favorable for carotid angioplasty and stenting; there is minimal to no tortuosity and adequate distal ICA for distal filter device deployment. In this case, a Cook Shuttle catheter was used for adequate access and support, a NAV6 filter for its simplicity of use, a noncompliant balloon angioplasty sized 1 mm less than the diameter of the ICA, a closed-cell stent (Xact) to reduce the risk of embolism, and IVUS to identify residual stenosis and debris within the lumen as well as stent apposition to the artery wall.

Tips, Tricks & Complication Avoidance • A stiff, robust guide catheter is necessary to avoid guide herniation into the aortic arch when the balloon, stent, or IVUS are advanced into position. • For crossing the lesion, a steerable 0.014-inch microwire is used. Shape the microwire tip to the unique anatomy of the patient’s stenotic lesion; usually a 45° bent is sufficient.

• If the stent is not easily passed through the lesion over the microwire, pre-stent angioplasty is performed with an undersized balloon. • An advantage of a closed-cell stent is that it can be recaptured in the case of initial malposition. This is not the case for open-cell stent.

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Case Overview

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CASE 11.2 Internal Carotid Artery Stenting and Angioplasty: Mesh-Covered Stent (Scaffold Trial)

• A 57-year-old male underwent medical evaluation prior to orthopedic surgery. On physical examination, he was found to have a left carotid artery bruit. His neurological exam was normal. • Carotid Doppler ultrasound demonstrated occlusion of the right internal carotid artery (ICA) and high-grade left ICA stenosis with

velocities > 350 cm/s. Magnetic resonance angiography (MRA) showed severe left ICA stenosis (90%). • Patient was a high risk for CEA because of contralateral ICA occlusion but required carotid artery treatment prior to elective orthopedic surgery.

Fig 11.2a  MRA demonstrating severe stenosis of the left internal carotid artery.

Fig 11.2b  Artist’s illustration of carotid artery stenting (mesh-covered stent) and angioplasty.

Fig 11.2c  Measurements of the vessel are obtained for proper stent and balloon angioplasty selection.

Fig 11.2d  Distal embolic protection device deployment.

11  Carotid Artery Stenting with Distal Protection

Fig 11.2e  Mesh-covered stent deployment.

Fig 11.2f  Post-stenting balloon angioplasty.

Fig 11.2g  Embolic protection distal filter device captured.

Fig 11.2h  Final cervical angiography demonstrating complete revascularization of the internal carotid artery.

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III  Extracranial Vessel Angioplasty/Stenting Video 11.2  Carotid artery stenting angioplasty using a mesh-covered stent (Scaffold trial)

Procedure • The patient underwent left carotid artery angioplasty and stenting with a distal filter protection device. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time more than 250. A Gore filter and a mesh-covered stent were used.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook Shuttle guide catheter (Cook Medical). • Gore embolic filter 7 mm. • Gore mesh-covered stent 6 x 8 x 30 mm. • Noncompliant aviator balloon 4.5 x 30 mm (Abbott). • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

This is a case of a patient with asymptomatic carotid artery stenosis and contralateral ICA occlusion making high risk for carotid endarterectomy. The anatomy of the carotid artery is favorable for carotid angioplasty and stenting with distal filter device. In this case, a mesh-covered stent was used. Second-generation meshcovered stents offer the potential advantage of improved plaque stabilization and reduction of procedural and postprocedural neurological events because of plaque embolization. The stent is designed as a flexible open-cell nitinol stent, with a 500-μm pore on the outside to stabilize plaque. It also coated with heparin bioactive surface to reduce the risk of thrombosis.

Tips, Tricks & Complication Avoidance • An advantage of a mesh-covered stent is plaque stabilization with reduction of plaque emboli. • The Gore filter and the mesh-covered stent could be difficult to observe during deployment; we recommend higher magnification during these steps of the procedure.

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• Be familiar with the mechanics of this filter and stent before use.

11  Carotid Artery Stenting with Distal Protection

Case Overview

CASE 11.3 Recurrent Right Internal Carotid Artery Stenosis

• A 69-year-old female presented with frequent spells of dizziness, syncope, and aphasia. Her neurological exam was normal. Patient has history of coronary artery disease, hypertension, hypothyroidism, and bilateral carotid artery endarterectomy (CEA) several years prior.

• Carotid Doppler ultrasound demonstrated right internal carotid artery (ICA) velocities of 550/130 cm/s. Patient was a high risk because of previous CEA.

Fig 11.3a  Angiography showing the severe right ICA stenosis.

Fig 11.3b  Artist’s illustration of carotid artery stenting and angioplasty of recurrent carotid stenosis.

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Fig 11.3c  Measurements of the vessel are obtained for proper stent and balloon angioplasty selection.

Fig 11.3d  Pre-stenting balloon angioplasty.

Fig 11.3c  Stent deployment.

Fig 11.3d  Final cervical angiography demonstrating complete revascularization of the internal carotid artery.

11  Carotid Artery Stenting with Distal Protection Video 11.3  Carotid artery stenting and angioplasty for recurrent stenosis after endarterectomy I

Procedure • The patient underwent right carotid artery angioplasty and stenting with distal filter protection device. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activated clotting time of more than 250. A SpiderFX was used as a filter protection device.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook shuttle guide catheter (Cook Medical). • 0.035-inch Glidewire. • Excelsior SL-10 microcatheter (Stryker). • Synchro 2 microwire exchange length (Stryker). • SpiderFX 5 mm embolic protection device (Medtronic). • Noncompliant Coyote ES 3 x 30 mm balloon (Boston Scientific). • Noncompliant Aviator 4 x 40 mm balloon (Abbott). • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Intravascular ultrasound. • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

This is a complex case of a patient with symptomatic recurrent carotid artery stenosis after previous carotid endarterectomy. The anatomy of the carotid artery is severely distorted as a consequence of previous surgery and restenosis. A microwire with a microcatheter were used to cross the severe stenosis. With an exchange wire, the embolic protection device was navigated and deployed. A SpiderFX 5-mm filter was used because of the relatively small size of the vessel. Two different-sized balloons were used to accomplish adequate angioplasty prior to the stent deployment. Intravascular ultrasound was used to confirm stent apposition and patency of the artery.

Tips, Tricks & Complication Avoidance • A stiff, robust guide catheter is necessary to avoid guide herniation into the aortic arch when the balloon, stent, or IVUS are advanced into position. • For crossing the lesion, a steerable 0.014-inch microwire is used. Shape the microwire tip to the unique anatomy of the patient’s stenotic lesion; usually a 45° bent is sufficient.

• If the stent is not easily passed through the lesion over the microwire, pre-stent angioplasty is performed with an undersized balloon. • An advantage of a closed-cell stent is that it can be recaptured in the case of initial malposition. This is not the case for open-cell stent.

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Case Overview

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CASE 11.4 Severe Recurrent Left Carotid Artery Stenosis after Carotid Endarterectomy

• A 69-year-old female presented with frequent spells of dizziness, syncope, and aphasia. Her neurological exam was normal. Patient has history of coronary artery disease, hypertension, hypothyroidism, and bilateral carotid artery endarterectomy (CEA) several years prior.

• Carotid Doppler ultrasound demonstrated right internal carotid artery (ICA) velocities of 700/300 cm/s. Patient was a high risk because of previous CEA.

Fig 11.4a  Cervical angiogram showing the severe left ICA stenosis.

Fig 11.4b  Artist’s illustration of carotid artery stenting and angioplasty after previous carotid endarterectomy.

Fig 11.4c  Area of severe stenosis crossed with a microwire.

Fig 11.4d  Embolic protection distal filter deployment.

11  Carotid Artery Stenting with Distal Protection

Fig 11.4e  Pre-stenting balloon angioplasty.

Fig 11.4f  Stent deployment.

Fig 11.4g  Complete revascularization of the left internal carotid artery.

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III  Extracranial Vessel Angioplasty/Stenting Video 11.4  Carotid artery stenting and angioplasty for recurrent stenosis after endarterectomy II

Procedure • The patient underwent left carotid artery angioplasty and stenting with distal filter protection device. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activated clotting time more than 250. A SpiderFX was used as a filter protection device.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook shuttle guide catheter (Cook Medical). • 0.035-inch Glidewire. • Spartacore 0.014-inch wire (Abbott). • Spider FX 5-mm embolic protection device (Medtronic). • Noncompliant Aviator 5 x 40 mm balloon (Abbott). • Carotid Xact stent 6 x 8 x 40 (Abbott Vascular). • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

This is a complex case of a patient with bilateral symptomatic recurrent carotid artery stenosis after previous bilateral carotid endarterectomy (same patient as Case 11.3). Similarly to the contralateral side, the anatomy of the carotid artery is severely distorted as a consequence of previous surgery and restenosis. A microwire with a microcatheter had to be used to cross the severe stenosis. A SpiderFX 5 mm filter was used because of the relatively small size of the vessel. Balloon angioplasty was performed prior to the stent deployment. A tapered closed-cell stent (Xact) was used because of its greater radial stiffness compared to open-cell stent and vessel mismatch.

Tips, Tricks & Complication Avoidance • Compared to open-cell stents, closed-cell stents have low flexibility and adaptability, more resistant to particle penetration, lower free-cell area, better scaffolding for fractured debris, and could kink a vessel. • Stent choices are made by vascular anatomy tortuosity and whether the lesion is high-risk symptomatic. Symptomatic vessel tortuosity is best treated with a flexible open-cell stent because it is easier to navigate and could be successfully deployed in this circumstance. A

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symptomatic high-risk lesion (ulcerated, hemorrhagic) is best treated with a closed-cell stent and a small free area. • Another variable to consider is the mismatch in vessel size between the common carotid artery and the internal carotid artery. A tapered stent is an excellent alterative to address this mismatch, as seen in the current case.

11  Carotid Artery Stenting with Distal Protection

Case Overview

CASE 11.5 Rescue Carotid Stenting Angioplasty after Acute Carotid Endarterectomy Complication

• A 68-year-old male presented to the emergency department with acute confusion, memory loss, and dysarthria. He has a past medical history of hypertension, hypercholesterolemia, and coronary artery disease. Neurologically, the patient was awake, alert, oriented, and nonfocal. His dysarthria had improved. • Computed tomography (CT) showed subacute left frontal infarction, and CT angiography (CTA) demonstrated heavily calcified severe left

internal carotid artery (ICA) stenosis. Carotid Doppler velocities on the left ICA were 350/110 cm/s. • Patient underwent left carotid endarterectomy (CEA). After the procedure, the patient woke up aphasic and with rightside hemiparesis. Emergent CTA and CT perfusion was obtained demonstrating a semi-occlusive intimal flap and left hemisphere increased time-to-peak on CT perfusion.

Fig 11.5a  Initial CT demonstrating a left frontal subacute stroke.

Fig 11.5b  Initial CT angiography showing heavily calcified left ICA stenosis.

Fig 11.5c  Postoperative (CEA) emergent CTP demonstrating increased time-to-peak on left hemisphere.

Fig 11.5d  Postoperative emergent CTA demonstrating the semi-occlusive intimal flap.

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Fig 11.5e  Artist’s illustration of carotid artery stenting and angioplasty.

Fig 11.5g  Crossing intimal free flap stenosis with microwire.

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Fig 11.5f  Area of severe stenosis caused by the intimal free flap.

Fig 11.5h  Stent deployment.

Fig 11.5I  Final cervical carotid angiography demonstrating complete revascularization of the left ICA.

11  Carotid Artery Stenting with Distal Protection Video 11.5  Rescue carotid artery stenting after carotid endarterectomy complication

Procedure • The patient underwent emergent left carotid artery stenting with no distal filter protection device. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • Envoy XB guide catheter (Codman). • 0.035-inch Glidewire. • Carotid Wallstent 6 x 22 mm (Boston Scientific). • Synchro 2 microwire (Stryker) • 6F AngioSeal percutaneous closure device.

This emergent case of intimal carotid artery injury after carotid endarterectomy is relatively uncommon. The patient was taken to interventional neuroradiology straight from the operating room. As the atherosclerotic plaque has already been surgically removed, the risk of embolic material is minimal; no embolic protection was used. A simple 6F guide catheter was navigated quickly into the common carotid artery and a stent was deployed to appose the free intimal flap against the carotid artery wall. An 6F Envoy catheter fits perfectly through a 6F femoral sheath.

Tips, Tricks & Complication Avoidance • If neurological examination worsens after CEA, do not hesitate to obtain CT angiography of head and neck to rule out intimal free flap, residual stenosis, arterial dissection, or intracranial arterial occlusion. • Post-CEA intimal free flap or arterial dissection are best treated with carotid stenting.

• Although not well-established in the literature, but based on case reports and on authors’ and editors’ experience, carotid stenting seems to be safe immediately after CEA. • There is no need for balloon angioplasty; the radial force of the stent alone is sufficient to correct an intimal free flap or dissection.

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Case Overview

CASE 11.6 Carotid Artery Stenting Angioplasty for Severe Carotid Artery Stenosis: Right brachial Artery Approach

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• A 67-year-old male presented to the emergency department with left transient hemiparesis. He has a past medical history of hypertension, peripheral artery disease, B-cell lymphoma, neck radiation, and recent bilateral femoral artery bypass. Neurological examination was normal.

• Computed tomography (CT) angiography demonstrated heavily calcified severe right internal carotid artery (ICA) stenosis. Carotid Doppler velocities on the left ICA were 459/126 cm/s.

Fig 11.6a  CT angiography showing heavily calcified left ICA stenosis.

Fig 11.6b  Artist’s illustration of carotid artery stenting and angioplasty through a brachial artery approach.

Fig 11.6c  Access into the right brachial artery is established.

Fig 11.6d  The Simmons 2 catheter is manipulated to access the right CCA.

11  Carotid Artery Stenting with Distal Protection

Fig 11.6e  The Simmons 2 catheter has accessed the right CCA (arrow).

Fig 11.6g  Balloon angioplasty.

Fig 11.6f  Right ICA stenosis (arrow).

Fig 11.6h  Stent deployment.

Fig 11.6i  Complete revascularization of the right ICA.

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III  Extracranial Vessel Angioplasty/Stenting Video 11.6  Brachial artery approach for carotid artery stenting and angioplasty

Procedure • Patient was high risk for carotid endarterectomy because of a history of neck radiation. Recent bilateral femoral artery bypass prevented from carotid artery stenting through a traditional femoral artery approach. • Patient underwent carotid artery stenting through a brachial artery approach, with a distal filter protection device. The procedure was performed under conscious sedation. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • Envoy XB guide catheter (Codman). • Simmons 2 catheter (Cook Medical). • 0.035-inch Glidewire. • Emboshield NAV6 distal filter (Abbott Vascular). • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Noncompliant Aviator balloon 3.5 x 30 mm (Abbott).

Brachial or radial artery are excellent alternatives to femoral artery approach. In this particular case, recent femoral artery bypass was a relative contraindication for femoral artery approach. Depending on the size of the brachial artery, it could accommodate a 6–8F sheath. We strongly recommend the use of ultrasound for brachial artery access. We advise the use of a slip catheter, such as Simmons 2 catheter, for easier access into the common carotid artery (CCA).

Tips, Tricks & Complication Avoidance • Obtain brachial artery access under ultrasound visualization. • Follow the wire and guide catheter under fluoroscopy along the brachial and subclavian arteries to prevent inadvertent access into an arterial branch. • Already have the guide catheter mounted on the slip (Simmons 2) catheter when selecting the common carotid artery. Once the slip

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catheter is in the desired carotid artery, simply slide the guide catheter over. • Follow the balloon angioplasty and stent under fluoroscopy through the guide catheter. The acute angle formed from the subclavian artery into the right carotid artery could create resistance and possible guide catheter herniation into the aortic arch.

12  Carotid Artery Stenting with Proximal Protection (Flow Arrest) Gary B. Rajah and Leonardo Rangel-Castilla

General Description Carotid artery revascularization is an effective method of stroke prevention in select patients with carotid stenosis. Carotid endarterectomy (CEA) has been performed routinely to achieve this goal. However, with the advancement of endovascular techniques protected carotid artery stenting (CAS) has become an excellent alternative to CEA. There are two different types of embolic protection: distal and proximal (accomplished via flow arrest or flow reversal). There are a few reports of combined proximal and distal protection as well. Devices used for proximal protection include the MoMa embolic protection device (Medtronic), balloon guide catheters (not tested on a large scale for this indication), and the Gore Flow Reversal System (Gore). In this chapter, proximal protection with flow arrest with the MoMa device is discussed. Distal protection is addressed in Chapter 11. Proximal protection under flow reversal using the Gore device and balloon guide catheters is discussed in Chapter 13. Stabile et al1 presented the results of a large series of proximal endovascular occlusion in 1300 patients. The procedure was successful in 99.7% of patients. Perioperative complications included five deaths (0.38%), six major strokes (0.46%), five minor strokes (0.38%), and no acute myocardial infarction. At 30 days of follow-up, two additional patients died (0.15%), and one patient had a minor stroke (0.07%). The 30day stroke and death incidence was 1.38% (n = 19). Symptomatic patients presented a higher 30-day stroke and death incidence when compared with asymptomatic patients (3.04% vs. 0.82%; p < 0.05). No significant difference in 30-day stroke and death rate was observed between patients at high (1.88%; n = 12) and average surgical risk (1.07; n = 7; p = NS). Independent predictors of adverse events included operator experience, symptomatic status, and hypertension.

Evidence-Based Outcomes The proximal protection with the MoMa device during carotid stenting (ARMOUR) Trial had the lowest event rates of any independently adjudicated study. The trial reported a 0.9% major stroke rate in symptomatic patients at 30 days. Proximal protection devices have the benefit of being in place before the lesion is crossed with any device. The MoMa device is able to arrest flow while the atherosclerotic lesion is crossed, aiding in protection from distal emboli and stroke. Furthermore, the device can be utilized in conjunction with a distal protection device should there be a need because of irregular anatomy or lack of confirmed flow arrest.

Indications CAS is indicated in patients with symptomatic internal carotid artery (ICA) stenosis > 70% or asymptomatic ICA stenosis > 80%. Other indications include the inability to tolerate general anesthesia during CEA, contralateral carotid occlusion or laryngeal nerve palsy, previous neck surgery or radiation therapy, restenosis after CEA, and poor neck mobility. CAS is also used for treatment of dissections and cases of acute stroke with tandem (extra- and intracranial vessel) occlusions. Proximal protection is used for extremely stenotic lesions that may be difficult to pass through with a microcatheter for distal protection. Another indication for proximal protection is a tortuous ICA or the presence of a loop at the distal ICA with no adequate landing zone for a distal protection filter device. Brittle, symptomatic, or hemorrhagic plaque lesions should also be considered for proximal protection.

Proximal protection devices with flow arrest are contraindicated in patients with contralateral ICA occlusion or patients who have relatively small femoral arteries that do not accommodate a 9F sheath.

Neuroendovascular Anatomy A brief overview of ICA anatomy is provided in Chapter 10. The anatomic considerations when using a MoMa device are somewhat more specific than those for other devices used for proximal protection (e.g., the Gore system or balloon guide catheters). The MoMa device relies on flow stagnation with occlusion of both the common carotid artery (CCA) and the external carotid artery (ECA). An inflated balloon in the CCA provides arrest of anterograde flow, while an inflated balloon in the ECA suspends retrograde flow. Therefore, any anatomic variant near the carotid bulb could theoretically result in loss of flow stagnation. For example, if the superior thyroid vessel extends from the CCA or very proximal ECA (between the balloons), this could result in backflow into the ICA and embolus. The spacing between the ECA and CCA balloons is fixed on the MoMa device and, therefore, anatomical variants must be identified. Overly tortuous carotid anatomy can make placement of the stiff MoMa device difficult. Extension of the carotid bulb plaque into the ECA can prevent safe passage of the device. It is important to identify aberrant anatomy because proatlantal persistent vessels could be disrupted during stenting or occlusion (flow arrest), resulting in posterior circulation stroke, especially if balloon occlusion is being utilized.

Periprocedural Medications As with the use of distal protection, dual antiplatelet therapy with aspirin (325 mg daily) and clopidogrel (75 mg daily) is administered for the prevention of intraluminal thrombus during or after the stenting procedure under proximal protection. The regimen is started 5–7 days prior to the procedure for elective procedures. Otherwise, a loading dose of aspirin (650 mg) and clopidogrel (600 mg) should be given before the procedure, followed by daily doses of aspirin (325 mg) and clopidogrel (75 mg). Dual antiplatelet therapy should be continued for at least 1 month. Aspirin should be continued indefinitely. Aspirin and clopidogrel serum responses should be monitored and therapeutic. Some patients can be nonresponsive or allergic to clopidogrel. Ticagrelor (60 mg twice daily) can be give as an alternative. Intraprocedural systemic heparinization is strongly recommended because of the ever-present risk of thrombus formation. An activated coagulation time between 250 and 300 seconds is the goal. Heparin administration prior to crossing the lesion may limit thrombus formation on devices positioned within the ICA. Hemodynamic instability sometimes occurs during balloon inflation for proximal protection and during balloon angioplasty. Bradycardia, asystole, and hypotension are the most common types. Asking the patient to perform a Valsalva maneuver (cough) will usually reverse bradycardia. A good practice is to have a vasopressor (e.g., dopamine or phenylephrine) available, as well as atropine. We typically perform CAS with the patient awake for accurate neurological assessment. The neurosurgeon or interventionist should be familiar with the MoMa device to limit the time of balloon inflation and flow arrest.

Specific Technique and Key Steps Several clinical trials have demonstrated the efficacy of embolic

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III  Extracranial Vessel Angioplasty/Stenting protection devices in preventing intraprocedural ischemic complications. When using a proximal embolic protection device (MoMa), the key steps for CAS are as follows (Fig. 12.1-12.4, Video 12.1-12.4). The MoMa device should be prepared before groin access: 1. Remove packaging and set aside three filters/traps to be used at the conclusion of the procedure. 2. Flush the working channel (center) and hollow mandrel with saline. 3. Insert the hollow mandrel though the working channel while rotating the valve. 4. Vacuum preparation of the ECA and CCA balloon channels are then completed with negative aspiration of air in an upright syringe containing 50:50 or 70:30 contrast material dilution. 5. Connect the safety connectors and two-way valves to ports. MoMa steps: 1. A 9 French sheath is placed in the femoral artery. 2. After the femoral angiogram has been performed, the diagnostic catheter (Simmons 2 or angled catheter, Terumo) surrounding the Glidewire (0.035-inch, Terumo) is advanced into the aorta under fluoroscopic guidance (Video 12.1-12.4). 3. Magnified working views of the carotid artery are obtained prior to entry into the ECA or exchange from the CCA. Measurements of the degree of stenosis, length of stenosis, and diameters of the CCA and distal ICA are obtained for proper stent sizing. 4. Roadmap technique is used for navigation of the diagnostic catheter into the ECA. Once the diagnostic catheter is in the ECA or in one of its large branches (internal maxillary or occipital arteries), an exchange of catheters is performed. 5. Under roadmap guidance and using an exchange-length (300 cm) stiff 0.035-inch wire (e.g., Supra Core 35, Abbott), the diagnostic catheter is exchanged for the MoMa catheter. Utmost care should be taken to prevent the wire, MoMa catheter, and diagnostic catheter, from crossing the stenotic lesion (Video 12.1-12.4). 6. The prepared MoMa proximal protection device is navigated through the arch up to the upper cervical ECA over the stiff exchange-length wire that is placed through the hollow mandrel. The distal balloon is placed in the ECA and the proximal balloon in the CCA. The hollow mandrel and the wire are removed (Video 12.1-12.4). 7. Selection of the stent: a. Closed cell stent—Xact (Abbott Vascular) or Wallstent (Boston Scientific)—is used for acute symptomatic ICA stenosis or with other high-risk features (hemorrhage or plaque morphology). b. Open-cell stent—Acculink (Abbott Vascular)—for tortuous anatomy. c. High-radial-force stents for heavily calcified lesions. d. Tapered stent when a large discrepancy between the diameters of the ICA and CCA is noticed. 8. The stent or pre-angioplasty balloon (if needed) is brought into the guide catheter and up to the proximal balloon. 9. The CCA and ECA balloons are then inflated with 50:50 or 70:30 contrast material under roadmap or fluoroscopy for ECA and CCA occlusion until flow arrest is obtained. 10. Flow arrest should be confirmed before crossing the lesion with any device by injecting a small amount of contrast material that should stagnate in the ICA. The stent envelops a stiff 0.014-inch wire (e.g., Spartacore 14, Abbott) that is brought up through the MoMa device. It is then navigated out of the opening between the two ECA and CCA balloons into the ICA and past the stenosis under flow arrest. This process must be completed quickly but safely because the flow is arrested! (Video 12.1-12.4) 11. Standard stent deployment is carried out under fluoroscopy. 12. A noncompliant balloon is used to perform angioplasty poststent placement if needed. 13. Intravascular ultrasound can be used to look for any residual stenosis or debris within the lumen and adequate stent apposition to the artery wall. 14. At the conclusion of the stent placement, the stagnant blood in the ICA (presumably with atherosclerotic plaque within) is aspirated ×3

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with a large 10 cc syringe and examined in the three filter/traps on the back table. There must be two clean traps prior to restoring flow via decompression of the balloons (Video 12.1-12.4). 15. Final angiographic runs are taken after the device has been removed. Hemostasis is established, and the femoral artery is closed with an AngioSeal device (Terumo) because of the large size (9F) of the femoral artery sheath (Video 12.1-12.4).

Device Selection In our practice, the following are common provisions and devices used for CAS with proximal protection under flow arrest. • 9F sheath. • 0.035-inch angled Glidewire. • 5F diagnostic catheter (Simmons 2 or angle catheter). • 0.035 Stiff exchange length wire (e.g., Supra Core 35). • 0.014-inch exchange wire (e.g., Sparta Core 14). • MoMa guide catheter (MoMa system) (Video 12.1-12.4). • Carotid stent (closed-cell Wallstent, Boston Scientific). • Noncompliant balloon. • Continuous heparinized flush.

Pearls • There are some caveats to proximal protection related to the MoMa device, including the need for a 9F sheath and additional setup time for preparation of the ECA and CCA balloons. • Some patients are unable to tolerate flow-arrest while awake. In those cases, the MoMa device cannot be utilized and the procedure has to be aborted. • Tortuous anatomy can make navigation of the MoMa device difficult. Extra purchase from the stiff wire can be acquired by looping it (i.e., the stiff wire) in an ECA vessel. • For crossing the lesion, a steerable 0.014-inch wire is used. Some angulation of the tip of the wire is recommended to ease the guidance of the wire through the area of stenosis and exit from the MoMa catheter. • In patients with tortuous anatomy or a looped ICA, navigation into the distal cervical ICA may be more difficult. The wire (0.0014 inch) on which the stent is mounted is passed to a point in the cervical ICA that enables passage of the stent safely beyond the stenosis. A stiffer wire might be required. • For stent placement, we recommend having an osseous landmark (cervical vertebrae) for a distal landing site of the stent because the roadmap may be unreliable because of vessel deformation with positioning of the stent or the guide catheter or because of patient movement. • If the stent is not easily passed through the lesion over the microwire, a pre-stent angioplasty is performed with an undersized balloon to prevent plaque rupture. • For closed-cell stents, a malpositioned stent may be recaptured if partially deployed (up to 80% for most closed-cell stents). Otherwise tandem stenting may be required. • Be careful when removing the MoMa guide catheter. The distal portion of the catheter containing the distal balloon can catch the proximal portion of the stent. Carefully pull the MoMa guide catheter into the CCA under fluoroscopy. • A final cerebral angiogram is always recommended to assess for smooth synchronized reperfusion and to identify any delayed capillary filling or large occlusions or dissections.

Reference [1] Stabile E, Salemme L, Sorropago G., et al. Proximal endovascular occlusion for carotid artery stenting. J Am Coll Cardiol. 2010;55:1661–1667.

12  Carotid Artery Stenting with Proximal Protection (Flow Arrest)

Case Overview

CASE 12.1 Carotid Stenting Angioplasty for Symptomatic Carotid Artery Stenosis with Proximal and Distal Protection

• A 40-year-old male was admitted to the emergency department with acute right hemiparesis and aphasia. Symptoms started more than 12 h prior to his presentation. Neurologically, the patient was awake, alert, aphasic, following commands on left side, with right side hemiparesis (3/5). He has past medical history of hypertension and

atrial fibrillation. Patient was not a candidate for intravenous tissue plasminogen activator. • Computed tomography (CT) was normal. CT angiography showed partial occlusion of the left common and internal carotid artery (ICA) and left middle cerebral artery by an intraluminal thrombus.

Fig 12.1a  Head CT angiography showing partial left middle cerebral artery occlusion.

Fig 12.1b  Neck CT angiography showing intraluminal thrombus causing partial occlusion of the common, external, and ICA.

Fig 12.1c  Artist’s illustration of carotid artery stenting with proximal protection balloon guide catheter for treatment of a large intraluminal thrombus.

Fig 12.1d  Balloon guide catheter creating flow arrest.

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Fig 12.1e  Distal embolic protection filter deployment.

Fig 12.1f  Stent deployment.

Fig 12.1g  Residual intraluminal thrombus at the common carotid artery below the initial stent.

Fig 12.1h  Second stent deployment to cover the proximal thrombus.

12  Carotid Artery Stenting with Proximal Protection (Flow Arrest)

Fig 12.1i  Final cervical carotid angiography demonstrating complete no intraluminal thrombus with adequate patency of the artery.

Fig 12.1j  Follow-up neck CTA showing no intraluminal thrombus and patent ICA.

Video 12.1  Flow limiting intraluminal carotid thrombus managed with carotid artery stenting—dual protection

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Procedure • Patient was admitted to the intensive care unit and started on intravenous heparin. After several days of heparin therapy, a repeat CT angiography (CTA) head and neck showed no improvement of the intraluminal thrombus. • Patient underwent carotid artery stenting to trap the thrombus between the stent and the carotid wall and to improve stenosis. The patient was loaded with dual antiplatelet medication prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,000 units of heparin were given to obtain an activated clotting time of more than 250. Proximal protection and distal filter were used simultaneously.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 7F dilator. – 9F sheath. • Concentric balloon guide catheter (Concentric Medical). • Vitek catheter (Cook Medical). • 0.038-inch Glidewire. • Emboshield NAV6 distal filter (Abbott Vascular). • 2 Carotid Wallstent 8 x 21 mm and 9 x 29 mm (Boston Scientific). • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

Carotid artery stenosis with proximal protection is indicated in patients with extremely severe stenosis, tortuous distal ICA with no appropriate landing zone for a distal filter, and large intraluminal thrombus. In the present case, proximal protection was used to reduce the risk of distal thrombus emboli while attempting to cross the distal filter. The balloon is inflated creating flow arrest, the thrombus is crossed, and the distal filter is deployed at C1 level. Once we have double protection, the stent is deployed in a standard fashion. There is no need for balloon angioplasty. Two stents were necessary to cover the entire thrombus length.

Tips, Tricks & Complication Avoidance • The majority of balloon guide catheters require a large (8F or 9F) femoral artery sheath. • Proximal protection devices with flow arrest are contraindicated in patients with contralateral ICA occlusion.

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• Be familiar with balloon guide catheters and know the proper balloon preparation. • Some patients are unable to tolerate flow-arrest while awake and the procedure has to be aborted.

12  Carotid Artery Stenting with Proximal Protection (Flow Arrest)

Case Overview

CASE 12.2 Carotid Stenting Angioplasty for Symptomatic Carotid Artery Stenosis with Flow Arrest (MoMA Catheter)

• A 62-year-old male admitted to the emergency department with transient left numbness and weakness. Neurologically, the examination was normal. Patient has a past medical history of hypertension, smoking, and coronary artery disease. Patient current medications include aspirin and clopidogrel.

• Computed tomography (CT) angiography showed severe (> 90%) right internal carotid artery (ICA) stenosis. Carotid Doppler velocities were 418/140 cm/s.

Fig 12.2a  Neck CT angiography showing severe ICA stenosis.

Fig 12.2b  Artist’s illustration of CAS with proximal protection balloon guide catheter.

Fig 12.2c  Dual balloon guide catheter (MoMA catheter).

Fig 12.2d  MoMA catheter positioned at the external carotid artery (ECA) and CCA.

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Fig 12.2e  Both balloons (ECA and CCA) are inflated creating flow arrest. Wire is crossing the stenosis site to obtain distal access.

Fig 12.2f  Balloon angioplasty.

Fig 12.2g  Stent deployment.

Fig 12.2h  Final cervical carotid angiography demonstrating complete ICA revascularization.

12  Carotid Artery Stenting with Proximal Protection (Flow Arrest) Video 12.2  Carotid artery stenting for critical carotid artery stenosis using dual balloon catheter

Procedure • Patient underwent carotid artery stenting (CAS) under flow arrest with dual balloon guide catheter (MoMA). The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 7F dilator. – 9F sheath. • Simmons 2 glide catheter. • 0.035-inch exchange Glidewire. • 0.035 Stiff exchange length wire (e.g., Supra Core 35). • 0.014 in exchange wire (e.g., Sparta Core 14). • MoMA balloon-guided catheter. • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Aviator balloon 3 x 20 mm (Abbott). • Intravascular ultrasound. • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

Carotid artery stenosis with proximal protection is indicated in patients with extremely severe stenosis and tortuous distal ICA with no appropriate landing zone for a distal filter. In the present case, proximal protection was used because the extremely severe stenosis could prevent the crossing of the distal filter device and also have the risk of intracranial plaque embolization. The MoMa device is able to arrest flow completely while the atherosclerotic lesion is crossed, aiding in protection from distal emboli and stroke.

Tips, Tricks & Complication Avoidance • The majority of balloon guide catheter require a large (8F or 9F) femoral artery sheath. • Patient should have a normal sized (3 mm) and patent ECA to be able to use the MoMa catheter. • Proximal protection devices with flow arrest are contraindicated in patients with contralateral ICA occlusion.

• Be familiar with the steps necessary to bring a MoMA catheter up into the ECA and common carotid artery. • When placing the MoMA catheter, make sure to have the ECA balloon proximal to the first ECA branch (superior thyroid artery) to achieve complete flow arrest.

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Case Overview

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CASE 12.3 Carotid Artery Near Occlusion Treated with Carotid Stenting Angioplasty with Flow Arrest (MoMa Catheter)

• A 78-year-old male presented with intermittent symptoms of right upper extremity numbness, word-finding difficulty, and imbalance. On examination he was neurologically intact. • Patient has a past medical history of hypertension and coronary artery diseases.

• Magnetic resonance imaging (MRI) with no evidence of acute stroke but significant lacunar old infarctions. • Computed tomography (CT) and MR angiography (MRA) showed severe (> 99%) right internal carotid artery (ICA) stenosis.

Fig 12.3a MRI with no acute strokes but significant chronic lacunar infarctions.

Fig 12.3b MRA with near complete occlusion of the left ICA.

Fig 12.3c CTA showing severe stenosis of the left ICA.

Fig 12.3d Artist’s illustration of CAS with proximal protection dual balloon guide catheter.

12 Carotid Artery Stenting with Proximal Protection (Flow Arrest)

Fig 12.3e ICA occlusion.

Fig 12.3f MoMA catheter positioned at the external carotid artery and common carotid artery and microwire prior to crossing stenosis.

Fig 12.3g Initial balloon angioplasty.

Fig 12.3h Stent deployment.

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Fig 12.3i  Successful carotid artery revascularization.

Fig 12.3j  Follow-up CT angiography at 3 months.

Video 12.3  Flow arrest carotid artery stenting for near occlusion carotid artery stenosis I

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12  Carotid Artery Stenting with Proximal Protection (Flow Arrest)

Procedure • Patient underwent carotid artery stenting (CAS) under flow arrest with dual balloon guide catheter (MoMA). Patient had been on dual antiplatelet regimen for 7 days prior to the procedure. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 7F dilator. – 9F sheath. • Simmons 2 glide catheter. • 0.035-inch exchange Glidewire. • 0.035 Stiff exchange length wire (e.g., Supra Core 35). • 0.014-inch exchange wire (e.g., Sparta Core 14). • MoMA balloon-guided catheter. • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Angioplasty balloon 3 x 20 mm (Abbott). • Angioplasty balloon 5 x 20 mm (Abbott). • 8F AngioSeal percutaneous closure device.

We elected to use proximal protection because of the severity of the stenosis (99%–100%). We wanted to obtain complete flow arrest before attempting crossing the stenosis. The anatomy was favorable for a MoMa guide catheter, adequate common carotid, and external carotid sizes. A microwire (0.014-inch) was used to minimize the risk of thromboembolism. The balloon angioplasty was performed before the stenting to prevent “watermelon seeding.” Two different-sized balloons (3 x 20 mm and 5 x 20 mm) were necessary to achieve adequate revascularization.

Tips, Tricks & Complication Avoidance • The multicenter Armour (proximal protection with the MOMA device during carotid stenting) trial evaluated the 30-day safety and effectiveness of the MOMA proximal cerebral protection device. Device success was 98.2% and procedural success was 93.2%. The 30day major stroke rate was 0.9%. This is the lowest stroke rate of any carotid artery stenosis treatment study. • Lesion crossing is a clear source of embolization. Several studies have demonstrated that, especially in tight, soft, and ulcerated plaques, embolization risk increases during this phase.

• Distal filter protection systems may cause plaque tearing and rupture during crossing a vulnerable lesion. • Carotid vasospasm is a periprocedural complication of CAS procedures. An intense symptomatic vasospasm may lead to acute neurological deficits during the procedure. High tortuosity index, long procedural duration, and female gender are independent risk factors for vasospasm during CAS. Use of distal filter devices is another predisposing factor.

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Case Overview

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CASE 12.4 Severe Carotid Artery Stenosis with Intraluminal Thrombus Treated with Carotid Stenting Angioplasty under Flow Arrest

• A 67-year-old female presented with subacute onset of left arm and leg weakness, dysarthria, and right amaurosis fugax. On examination she was alert, oriented, with left facial palsy, and mild left hemiparesis. • Patient has a past medical history of hypertension and peripheral artery diseases.

• Computed demonstrated subacute right frontal and parietal ischemic strokes. • Computed tomography (CT) and magnetic resonance angiography showed severe (> 99%) right internal carotid artery (ICA) stenosis.

Fig 12.4a CT demonstrating right frontal subacute strokes.

Fig 12.4b Severe stenosis of the right ICA with intraluminal thrombus (red arrow).

Fig 12.4c Artist’s illustration of CAS for carotid artery stenosis with intraluminal thrombus under flow arrest.

Fig 12.4d Severe ICA stenosis with associated intraluminal thrombus (red arrow).

12 Carotid Artery Stenting with Proximal Protection (Flow Arrest)

Fig 12.4e MoMA catheter positioned at the external carotid artery and common carotid artery.

Fig 12.4f Microwire crossing the stenosis under flow arrest.

Fig 12.4g Initial balloon angioplasty.

Fig 12.4h Stent deployment.

Fig 12.4i Successful carotid artery revascularization.

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III  Extracranial Vessel Angioplasty/Stenting Video 12.4  Flow arrest carotid artery stenting for near occlusion carotid artery stenosis II

Procedure • Patient underwent carotid artery stenting (CAS) under flow arrest with a dual balloon guide catheter (MoMA). Patient had been on dual antiplatelet regimen for 7 days prior to the procedure. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 7F dilator. – 9F sheath. • Simmons 2 glide catheter. • 0.035-inch exchange Glidewire. • 0.035 Stiff exchange length wire (e.g., Supra Core 35). • 0.014-inch exchange wire (e.g., Sparta Core 14). • MoMA balloon-guided catheter. • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Angioplasty balloon 3 x 20 mm (Abbott). • Angioplasty balloon 5 x 20 mm (Abbott). • 8F AngioSeal percutaneous closure device.

We elected to use proximal protection because of the severity of the stenosis (95%) but most importantly because of the presence of an intraluminal thrombus. Symptomatic intraluminal thrombus refractory to medical treatment (heparin) are best treated with carotid stenting. The risk of propagating thrombus intracranially while passing a distal filter is high, therefore, flow arrest is ideal for these types of lesions. A microwire (0.014-inch) was used to minimize the risk of thromboembolism. Two different sized balloons (3 x 20 mm and 5 x 20 mm) were necessary to achieve adequate revascularization.

Tips, Tricks & Complication Avoidance • There is an absolute potential risk for plaque material dislodging and microembolization of debris in CAS procedures. Each stage of the intervention—lesion crossing, predilatation, stenting and postdilatation—increases the risk of cerebral microemboli and associated stroke. • Distal filter protection systems may cause plaque tearing and rupture during crossing a vulnerable lesion.

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• Some patients do not tolerate long episodes of flow arrest. Be fast, safe, and efficient. • Communicate with the anesthesiologist during balloon angioplasty as it could cause transient bradycardia. Most of the time, it resolves on its own or by asking the patient to perform a Valsalva maneuver (e.g., coughing).

13  Carotid Artery Stenting under Flow Reversal Jason M. Davies

General Description Although carotid artery stenosis can be successfully treated with either endarterectomy or stenting, certain patient populations have elevated risks for each procedure. Consequently, transcarotid artery revascularization (TCAR) was developed to apply surgical principles of embolic protection in patients for whom surgery is less desirable. Specifically, TCAR utilizes flow reversal by creating a temporary shunt between the carotid artery and the femoral vein, thus allowing for placement of a stent while minimizing embolic risk to the brain.

Indications TCAR has the lowest documented 30-day stroke rate of any carotid revascularization intervention. Indications include both symptomatic and asymptomatic high-grade carotid artery stenosis. Because TCAR obviates accessing the arch, arch type, calcifications, and soft plaque that elevate risk for transfemoral or transradial stenting are less concerning. Furthermore, distal tortuosity in the carotid artery is better tolerated under TCAR because it is not necessary to deploy distal protection. Cases with carotid plaques that demonstrate circumferential calcification should be avoided.

Neuroendovascular Anatomy The common carotid arteries (CCAs) typically arise from the brachiocephalic trunk (right and bovine left) or aortic arch (left). The carotid artery then passes obliquely under the sternoclavicular joint, deep to the distance between the two heads of the sternocleidomastoid, as it courses into the lateral neck. At the C3 vertebral level, the CCA usually bifurcates into the internal and external carotid arteries, which supply the brain and face, respectively. The distance between the clavicle and bifurcation is approximately 10 cm. This is the segment that will be accessed for TCAR. To create flow reversal, a TCAR shunt is created between the CCA and the femoral vein (details below). The left femoral vein is preferred for ergonomic reasons and is accessed just medial to the femoral artery in the femoral triangle.

Specific Technique and Key Steps 1. Initial access of the target carotid artery begins with identification of the CCA 1 cm above the clavicle. A 2-cm horizontal incision is marked overlying the CCA. 2. The skin is incised with a 10-blade, and skin hooks are utilized to retract the skin. Using a combination of blunt dissection with Metzenbaum scissors and electrocautery, the subcutaneous tissues and fat are carefully dissected to expose and circumferentially dissect a 2-cm length of the CCA, staying between the two heads of the sternocleidomastoid muscle. Ultrasound guidance and palpation of the pulse can guide the exposure (Fig. 13.1, Video 13.1). 3. A vessel loop is wrapped around the carotid artery twice and a Rumel tourniquet is loosely placed to establish proximal vascular control. 4. A purse-string suture is placed into the exposed superior surface of the carotid artery using 6-0 prolene and Castroviejo needle drivers.

5. Left femoral vein access is obtained as previously described in the femoral vein access chapter. The TCAR venous sheath is placed into the vein and secured with a silk suture. 6. The TCAR arterial sheath is placed into the exposed carotid artery using a modified Seldinger technique. The central area, rimmed by the purse-string suture, is utilized to facilitate arteriotomy closure at the completion of the case. The sheath is secured to the skin with a silk suture. 7. Placement of the sheath in the CCA is verified with fluoroscopy. Cervical and cranial angiographic runs are obtained to assess anatomy and aid in device selection (Fig. 13.1, Video 13.1). 8. Heparin is administered intravenously to the patient, and therapeutic activated coagulation time verification is established. 9. The carotid stent should be selected based on the diameter of the CCA and with sufficient length for placement that starts within a straight segment of the internal carotid artery and extends securely into the CCA. 10. The TCAR shunt apparatus is attached to the arterial sheath and allowed to fill with blood to flush out all air. Once the apparatus is completely flushed, it is connected to the venous shunt. Flow is activated, shunting blood from the carotid artery to the femoral vein. The vessel loop is tightened to occlude the proximal CCA and complete the flow reversal process (Video 13.1). 11. With flow reversed, the selected stent and wire are introduced through the arterial sheath. The wire is advanced through the stenotic lesion and into the horizontal petrous segment. 12. The practitioner can proceed with presenting angioplasty of a high-grade lesion or stenting if no angioplasty is anticipated. Both procedures proceed as per standard protocols (see Chapter 10), and the devices are withdrawn. (Video 13.1) 13. Post-stenting angiographic runs of both cervical and intracranial vasculature are obtained to verify stent placement and evaluate for thrombus. 14. The wire is withdrawn after all stent manipulations have been completed. 15. The shunt is turned off, and the apparatus is disconnected. 16. The arterial sheath is withdrawn as the purse-string suture is tightened and tied to close the carotid arteriotomy. 17. The tourniquet is released to reestablish anterograde flow. 18. The neck wound is closed in layers using standard surgical technique. 19. The venous access is removed and the vessel closed by applying manual pressure.

Device Selection • TCAR procedure: – Micropuncture kit. – TCAR sheaths and shunt apparatus (Enroute system, Silk Road Medical). – Vessel loop. – Rumel tourniquet. • Carotid stenting: – 0.014-inch stiff microwire (Synchro 2, Stryker). – Carotid stent. – 0.014-inch angioplasty balloon.

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Pearls • A low carotid bifurcation may reduce the length of the CCA, so care must be taken not to advance the arterial sheath into the stenotic lesion. • Ultrasound is a useful adjunct for localizing the CCA at the cut-down site because the patient’s body habitus may impair the ability to identify a palpable pulse. • Typical flow reversal time is approximately 10 minutes and is often well-tolerated by patients. • Care should be taken not to incorporate too much of the arterial wall with the purse-string suture to avoid stenosing the vessel. • Be very familiar with the TCAR device before a procedure is attempted (Video 13.1).

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13  Carotid Artery Stenting under Flow Reversal

Case Overview

CASE 13.1 Direct Carotid Cut-Down and Flow Reversal (Silk Road) for Stenting Angioplasty of Internal Carotid Artery and Brachiocephalic Artery Ostial Stenosis

• A 70-year-old female presented for annual carotid Doppler ultrasound follow-up. Over the last 18 months, she had experienced transient left lower extremity paresthesias. On examination, she was neurologically intact. • Patient has a past medical history of hypertension coronary artery disease, stroke, and COPD. She had a right carotid endarterectomy (CEA) 16 years ago.

• Carotid Doppler revealed velocities of 330/115 cm/sec on the right internal carotid artery (ICA). Magnetic resonance angiography demonstrated 80% right ICA stenosis and 60% brachiocephalic ostial stenosis. • Because of the anatomical location of both stenosis we decided to perform carotid artery and brachiocephalic ostial stenting using direct carotid cut-down and flow reversal using the Enroute Silk Road device.

Fig 13.1a  Right ICA stenosis.

Fig 13.1b  Brachiocephalic ostial stenosis.

Fig 13.1c  Artist’s illustration of internal carotid artery and brachiocephalic ostial stenosis treated with stenting angioplasty under flow reversal.

Fig 13.1d  Direct common carotid cut-down for vascular access.

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Fig 13.1e CCA and ICA stenosis.

Fig 13.1f Flow reversal system.

Fig 13.1g Crossing internal carotid artery stenosis under flow reversal.

Fig 13.1h Internal carotid artery and brachiocephalic ostial balloon angioplasty.

Fig 13.1i Internal carotid artery and brachiocephalic stent deployment.

Fig 13.1j Successful Internal carotid artery and brachiocephalic revascularization.

13  Carotid Artery Stenting under Flow Reversal Video 13.1  Flow reversal carotid artery stenting for tandem stenosis—Enroute Stent System

Procedure • Patient underwent carotid artery stenting under flow reversal with a Silk Road device. Patient had been on dual antiplatelet regimen for 7 days prior to the procedure. The procedure was performed under general anesthesia and through a direct right common carotid artery (CCA) access and exposure. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. – 7F destination sheath 90 cm. – 8F 45-cm long sheath. • 0.035-inch exchange Glidewire. • 0.014 Stiff Sparta Core 14 190 cm wire. • Enroute Transcarotid Stent System. • 6 x 8 x 40 Xact stent. • 7 x 38 x 80 atrium-covered stent. • Angioplasty balloon 4.5 x 30 mm (Aviator). • Angioplasty balloon 10 x 40 mm (Evercross). • Intravascular ultrasound (IVUS). • 6F AngioSeal percutaneous closure device.

This patient had symptomatic ICA restenosis from previous CEA. She also developed stenosis of the brachiocephalic ostium. A transfemoral or transradial approach for ICA stenting requires adequate patency of the brachiocephalic trunk. Stenting and angioplasty of brachiocephalic ostium is an extremely challenging procedure from a transfemoral approach. A direct common carotid access allows for ICA and brachiocephalic ostium stenting during the same procedure. A Silk Road device creates temporary flow reversal (right ICA-femoral vein). The shunt apparatus is attached to the arterial sheath and allowed to fill with blood to flush out all air. Once the apparatus is completely flushed, it is connected to the venous shunt. Flow is activated, shunting blood from the carotid artery to the femoral vein. A vessel loop is tightened to occlude the proximal CCA and complete the flow reversal process. Once flow reversal is created, the carotid stenting and brachiocephalic ostium stenting are completed using the same principles of vessel stenting. At the end, the shunt is turned off and the arterial sheath is withdrawn as the purse-string suture is tightened and tied to close the carotid arteriotomy.

Tips, Tricks & Complication Avoidance • Results of The Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER) multicenter trial demonstrate that the use of the Enroute Transcarotid Neuroprotection System is safe and effective at preventing stroke during CAS. The overall stroke rate of 1.4% is the lowest reported to date for any prospective, multicenter clinical trial of CAS. • Although uncommon, neurological intolerance to flow reversal may occur once the CCA is clamped and is usually manifested by confusion, agitation, or a slow decline in the level of consciousness.

• The arterial access sheath can make an acute bend over the clavicle as it enters the CCA. Serial dilatation of the arteriotomy, large and stiff wire (0.038-inch wire) in the external carotid artery prevents acute bends of the arterial sheath. • Meticulous dissection will avoid neural structures. Vascular clamps on the CCA without direct vision should be avoided.

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14  Angioplasty for In-Stent Restenosis or Recurrent Stenosis Gary B. Rajah and Leonardo Rangel-Castilla

General Description The long-term (10-year) follow-up results of the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) were reported in 2013. Restenosis occurred or revascularization was performed in 12.2% of patients treated with carotid artery stenting (CAS) in the trial. Although restenosis is not a common occurrence, the need for revascularization in previously stent-treated patients does arise, especially if the patient becomes symptomatic. The in-stent stenosis can be the result of continued plaque rupture and rerupture versus neointimal hyperplasia over the carotid stent. Different treatment options for instent stenosis include balloon angioplasty with or without the placement of another stent and carotid endarterectomy. Cutting balloons can also be used for angioplasty in these cases. These balloons reportedly offer minimal plaque disruption while allowing expansion of the vessel diameter. In the authors’ practice, a stepwise approach is preferred, starting with conventional balloon angioplasty performed under embolic protection, followed by cutting balloon or drug-eluting balloon angioplasty. The placement of a second stent is the last option because of the risk of narrowing the arterial lumen. If the stenosis is because of intimal hyperplasia, we may select an open-cell stent with a higher radial opening force (e.g., Protégé, Covidien) versus a closed-cell stent (e.g., Wallstent, Boston Scientific). The key to reducing the incidence of in-stent stenosis is achieving a good result at the time of the first CAS procedure. Balloon angioplasty for in-stent stenosis should be performed with either a proximal or distal protection device depending on whether the stenosis can be crossed.

Indications The indications for revascularization of in-stent stenosis include a symptomatic patient with > 70% in-stent stenosis. Symptomatic patients with lower degrees of stenosis should be investigated for unstable plaques for which intervention may be required. Asymptomatic patients with > 80% stenosis should also be considered for intervention.

Neuroendovascular Anatomy Please see Chapter 10 for carotid artery anatomy. Anatomical issues that should be addressed when evaluating in-stent stenosis include the location of the stenosis (mid, proximal, or distal stent). The location of the stenosis can give clues to the underlying pathology (continued plaque buildup vs. neointimal hyperplasia vs. endoleak). The stenosis should be examined for ulcerations or a smooth circumferential appearance (indicating hyperplasia). (If the plaque is ulcerated, consideration is given to the use of proximal protection instead of distal protection.) Kinking above or below the straight stented portion of the vessel can also create stenosis or turbulent areas of flow that are prone to pathology.

Periprocedural Medications Patients should already be placed on dual antiplatelet therapy with aspirin (325 mg daily) and clopidogrel (75 mg daily) because of the previous stent treatment. Before the recurrent stenosis procedure, platelet function should be tested and within a therapeutic range in an effort prevent platelet aggregation on any exposed stent following angioplasty or possible intimal disruption that could result in the

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formation of an intraluminal thrombus during or after the procedure. An alternative to clopidogrel is ticagrelor (60 mg twice daily per chapter 10) in place of clopidogrel. Systemic heparinization is administered during the procedure because of the risk of intraprocedural thrombus formation. A weight-based bolus of heparin aimed at an activated coagulation time of 250–300 seconds may limit thromboembolic complications. The administration of heparin prior to crossing the lesion may limit thrombus formation on devices positioned within the internal carotid artery (ICA). Glycoprotein IIb/IIIa inhibitors are utilized for acute thrombus formation during the procedure. Hemodynamic instability may occur during CAS and balloon angioplasty performed for the treatment of in-stent stenosis. Bradycardia, asystole, and hypotension are the most common events. Asking the patient to perform a Valsalva maneuver (or cough) will usually reverse bradycardia. A good practice is to have a vasopressor (e.g., dopamine or phenylephrine) available, as well as atropine. We typically perform the angioplasty procedure with the patient in an awake state (i.e., conscious sedation) for accurate neurological assessment.

Specific Technique and Key Steps 1. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a curved wire (0.035-inch angled Glidewire, Terumo) into the aorta under fluoroscopic guidance. 2. Depending on the arch anatomy, the guide catheter can be brought up directly over a 0.035-inch angled Glidewire or advanced over a 4–5F intermediate diagnostic catheter, such as a Vitek or Berenstein catheter (Cook). Utmost care should be taken to prevent the wire, catheter, or guide from crossing the stenotic in-stent lesion (Fig. 14.1, 14.2, Video 14.1, 14.2). 3. Magnified working views of the carotid artery are obtained. Measurements of the degree of stenosis, length of stenosis, and diameters of the CCA and distal ICA are obtained for proper sizing of the stent. 4. A proximal or distal protection device is selected based on operator choice. See Chapters 10 and 11 for a description of the types of protection devices. A distal protection device (a filter type of device, the Emboshield NAV6 (Abbott), was used here. 5. The distal embolic protection device is navigated through the stenosis up to the upper cervical ICA and deployed under fluoroscopy. 6. Under road-mapping guidance, the filter and the noncompliant balloon are advanced over the wire to the area of stenosis. Typically, a rapid exchange system is utilized. 7. The balloon is undersized 1 mm less than the diameter of the ICA. The balloon is inflated up to the nominal pressure specified by the manufacturer (Fig. 14.1, 14.2, Video 14.1, 14.2). 8. Angioplasty is performed. The balloon is kept inflated for 30 seconds if tolerated by the patient. If not tolerated, the balloon is inflated for only a few seconds (5–10 s) multiple times. The balloon is inflated gradually (Video 14.1, 14.2). The patient’s heart rate is monitored closely during this process. 9. A post-angioplasty angiographic run is performed. If the dilation is adequate (excellent, < 30% residual stenosis; good, 30%–50% residual stenosis), no further treatment is needed and the balloon can be removed. If not, the balloon can be utilized for a second angioplasty or it can be removed and a stent can be deployed. We recommend covering both ends of the previous stent by at least 5 mm to prevent endoleaks (Video 14.1, 14.2).

14  Angioplasty for In-Stent Restenosis or Recurrent Stenosis 10. Intravascular ultrasound can be used to look for residual debris within the lumen or residual stenosis as well as stent-to-wall approximation. 11. The distal protection device is captured and removed, typically via a separate sheath.

Device Selection In the authors’ practice, the following are the common set-ups and devices used for the treatment of in-stent restenosis or recurrent stenosis: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy XB catheter or Cook-Shuttle, Cook). • 0.035-inch angled Glidewire. • Intermediate 5F diagnostic catheter (Vitek, Cook). • Distal protection device (i.e., Emboshield NAV6 embolic protection device; or proximal protection device, MoMa, Medtronic). • Carotid stent—if necessary (closed-cell Wallstent). • Noncompliant balloon (Viatrac, Abbott).

• Distal capture device (protection device-manufacturer specific). • Continuous heparinized flush.

Pearls • An endoleak from the initial stent placement can cause poor endothelialization and result in thrombus formation. • A carotid stent with a high radial force opening (e.g., Protégé) can be used for stubborn recurrent stenosis. • Care must be taken not to entangle or pass a guidewire or balloon through a cell of the previously placed stent, as this could damage or dislodge the stent. • Cutting balloons (e.g., Flexotome Cutting Balloon Dilatation Device, Boston Scientific) are coronary balloons but have also been used with some success for the treatment of in-stent carotid restenosis or recurrent stenosis. Again, care must be taken not to damage or dislodge the existing stent. • Close surveillance with noninvasive imaging (e.g., ultrasonography) is needed for patients with in-stent stenosis.

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Case Overview

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CASE 14.1 Balloon Angioplasty for Carotid Artery In-Stent Stenosis

• A 74-year-old male presented to the vascular neurosurgery clinic for routine follow-up. The patient is currently asymptomatic. His neurological examination is normal. He has a past medical history of hypertension and carotid artery disease. He had previous symptomatic left internal carotid artery (ICA) stenosis treated with carotid stenting

angioplasty 4 years ago. On carotid Doppler ultrasound, he was found to have significant increased velocities. • Carotid Doppler velocities: Left ICA 280/137 cm/sec. • Further work-up with diagnostic cerebral angiogram demonstrated significant in-stent stenosis.

Fig 14.1a Cervical angiography showing carotid artery in-stent stenosis.

Fig 14.1b Artist’s illustration of in-stent stenosis treated with balloon angioplasty.

Fig 14.1c Embolic protection filter device deployed at C1 level.

Fig 14.1d Inflating balloon.

14 Angioplasty for In-Stent Restenosis or Recurrent Stenosis

Fig 14.1e Balloon angioplasty.

Fig 14.1f Intravascular ultrasound demonstrating adequate stent apposition with significant improvement of the stenosis.

Fig 14.1g Successful resolution of the in-stent stenosis.

Video 14.1 Carotid artery in-stent stenosis treated with balloon angioplasty

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Procedure • The patient underwent left ICA balloon angioplasty alone with a distal filter protection device. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook Shuttle guide catheter (Cook Medical). • 0.035-in Glidewire (Terumo). • NAV6 distal filter device (Abbott). • Aviator 4.5 x 30 mm angioplasty balloon (Abbott). • Intravascular ultrasound (IVUS). • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

This is a case of a patient with asymptomatic carotid artery stenosis based on Doppler ultrasound velocities, he had developed severe in-stent stenosis. The endovascular approach is very similar to carotid artery stenting. We recommend the use of a distal filter device. When passing the wire through the stent, be careful as the wire could get caught within the tines of the stent and alter the shape of the wire. Do a proper size selection of the angioplasty balloon and maintain the balloon inflated for several minutes or as long as the patient tolerates.

Tips, Tricks & Complication Avoidance • In-stent restenosis is an infrequent but well-known risk after carotid artery stenting usually resulting from early neo-intimal hyperplasia. • We do not recommend the use of another stent to treat in-stent stenosis, as adding more metal in the presence of neo-intimal hyperplasia could result in further stenosis. • Female sex, dyslipidemia, history of surgical endarterectomy and diabetes are independent risk factors for in-stent restenosis. Anatomical risk factors include high-grade stenosis or a lack of coverage of the common carotid artery.

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• If the balloon angioplasty is overinflated the stent could fracture. • Consider using a cutting balloon or drug-eluting balloon for multiple recurrences of in-stent stenosis.

14 Angioplasty for In-Stent Restenosis or Recurrent Stenosis

Case Overview

CASE 14.2 Recurrent Carotid Artery In-Stent Stenosis: Drug-Eluting Balloon Angioplasty

• This is an 84-year-old male with a history of bilateral symptomatic carotid artery stenosis treated originally with carotid stenting and angioplasty. He had developed recurrent symptomatic left common carotid artery (CCA) in-stent stenosis requiring multiple balloon angioplasties. He presents to the clinic complaining of transient right upper numbness. His neurological examination is normal. He had past medical history of hypertension, diabetes, coronary, and peripheral

artery diseases. Carotid Doppler ultrasound suggested severe in-stent stenosis of the left CCA stent, with velocities exceeding 500/240 cm/ sec. • Diagnostic cerebral angiogram demonstrated severe left CCA instent stenosis. The patient had previous several balloon angioplasty, including a cutting balloon angioplasty.

Fig 14.2a Cervical angiography showing carotid artery in-stent stenosis.

Fig 14.2b Artist’s illustration of carotid artery stenting and angioplasty with a drug-eluting balloon.

Fig 14.2c Left ICA recurrent in-stent stenosis.

Fig 14.2d Inflating balloon.

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Fig 14.2e Balloon angioplasty.

Fig 14.2f Intravascular ultrasound demonstrating adequate stent apposition with significant improvement of the stenosis.

Fig 14.2g Successful resolution of the in-stent stenosis.

Video 14.2 Recurrent carotid artery in-stent stenosis treated balloon angioplasty (drug-eluting balloon)

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Procedure • The patient underwent left common carotid artery balloon angioplasty with a distal filter protection device. The balloon used was a drug-eluting balloon. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook Shuttle guide catheter (Cook Medical). • 0.035-in Glidewire (Terumo). • NAV6 distal filter device (Abbott). • Lutonix 4.0 x 40 drug-eluting (Placlitaxel) balloon. • Intravascular ultrasound (IVUS). • Distal filter capture device. • 8F AngioSeal percutaneous closure device.

This patient had recurrent in-stent stenosis and had multiple previous balloon angioplasty, including cutting balloon angioplasty in one occasion. He has symptomatic severe progressive neo-intimal hyperplasia that could lead to carotid occlusion. The endovascular approach is very similar to carotid artery stenting or standard balloon angioplasty. Maintain the balloon inflated for several minutes or as long as the patient tolerates, allowing the drug to penetrate into the endothelial cells.

Tips, Tricks & Complication Avoidance • Drug-eluting balloons work as follows: the drug adheres to the balloon membrane and is partially hidden below the folds, which are wrapped around the shaft. Upon inflation solid paclitaxel particles are pushed into the vessel wall. • Once paclitaxel is transferred into the vessel wall, it acts by altering cytoskeletons in cells and irreversibly inhibiting arterial smooth muscle cell proliferation.

• Paclitaxel is an effective antineoplastic agent and still the drug of choice. • Keep the balloon inflated for several minutes or as long as the patient tolerates.

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15  Vertebral Artery Stenting Jason M. Davies

General Description Vertebral artery (VA) stenosis often presents with posterior circulation stroke or with symptoms of vertebrobasilar insufficiency. Nearly a quarter of patients presenting with such symptoms are found to have > 50% stenosis in the vertebrobasilar system. Duplex ultrasound imaging may reveal to-and-fro flow patterns, diminished waveforms, or even retrograde flow, indicating subclavian artery steal. The most common area of VA stenosis is at its origin off the subclavian artery. Stenting has been used to reduce stenosis, restore flow patterns, and reduce the overall risk of recurring symptoms.

Indications The decision to open a stenosed VA is guided by (1) the degree of stenosis in the impacted vessel, (2) the presence of symptoms or magnetic resonance–verified strokes attributable to the stenosis, and (3) the relative dependency on the affected vessel. Symptoms may be from one of two etiologies, namely, flow-related because of reduced flux through a fixed stenosis, or thromboembolic because of plaque rupture or turbulent flow across the plaque. The former should be augmented with stenting, whereas the latter may be reasonably treated with maximal medical management consisting of dual antiplatelet and high-dose statin therapies. Because the posterior circulation typically has a redundant supply, an atretic or compromised contralateral vessel increases the need for revascularization, whereas a robust or even dominant contralateral supply may decrease the need. The neurointerventionist’s judgment should be personalized based on the confluence of patient factors.

Neuroendovascular Anatomy The paired VAs arise from the subclavian arteries. They course caudally and enter the foramen transversaria at approximately the level of the C6 vertebra. Within the bony foramen, they rise to the C2 level before exiting to cross the C1 arch, run through the suboccipital triangle, and enter the foramen magnum. The VAs join at the vertebrobasilar junction anterior to the brainstem to form the basilar artery. The VA can be divided into four segments as follows: V1 (pre-foraminal) extending from the origin off the subclavian artery to insertion into the foramina of the transverse processes, V2 (foraminal) extending from C6 to where the artery exits at C2, V3 (extradural) encompassing the segment extending from the foraminal exit at C2 to where the artery pierces the dura at the foramen magnum, and V4 (intradural) extending from the dural origin to the vertebrobasilar junction anterior to the brainstem.

Specific Technique and Key Steps 1. Noninvasive imaging consisting of computed tomography angiography extending from the aortic arch to the vertex is invaluable in assessing the access route and planning the intervention. Often, the VA is more easily accessed using an ipsilateral radial or distal radial artery approach, particularly for right-sided lesions. However, a proximal takeoff from the subclavian artery or the arch origin of the left VA may make transfemoral approaches more technically desirable. The route of choice is selected, and 6 French (F) access is obtained with a long sheath (Fig. 15.1, Video 15.1).

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2. The long sheath is advanced over a 0.035-inch wire under roadmap guidance to a position just proximal to the VA origin. The wire is then removed. 3. To evaluate the vasculature and obtain proper views for placement of the stent, angiographic runs of the cervical and intracranial vessels are obtained prior to placing the stent. Ideally, the VA origin will be visible on the anteroposterior images, and the lateral images can help to show the vertebral arch around C1, which will be the destination for distal wire access in cases of VA origin stenting (Video 15.1). 4. A balloon-mounted stent is backloaded on the microwire system, and a slight hockey stick shape is placed in the wire to guide it through the stenosis (Fig. 15.1, Video 15.1). 5. The stent and wire are advanced to the tip of the guide catheter within the subclavian artery, and fresh runs are obtained. 6. Under roadmap guidance, the wire is advanced through the stenosis and into the distal cervical VA, usually just proximal to the C1 arch. 7. The stent is advanced into the stenosis and placed two-thirds within the vessel with one-third overhanging into the subclavian artery. The balloon is inflated to the appropriate pressure as described in the manufacturer’s guidelines to obtain adequate wall apposition and opening of the stenosis (Fig. 15.1, Video 15.1). 8. The balloon is deflated while aspirating from the guide catheter to avoid distal emboli (Video 15.1). 9. Follow-up runs are obtained of the cervical and intracranial vasculature to ensure adequate placement of the stent, resolution of the stenosis, and that no distal emboli have resulted (Video 15.1). 10. The wire and guide catheter are withdrawn, and the access point is closed.

Device Selection • Access: – Radial access kit. – 45-cm Destination sheath (Terumo) or other 6F long sheath for radial access route. – 0.035-inch angled exchange-length Glidewire. • Stent: – Drug-eluting stent, balloon-mounted stent for arteries up to 5.5 mm, or – Bare-metal, balloon-mounted stent for arteries in excess of 5 mm. – 0.014-inch wire such as Sparta Core (Abbott Vascular).

Pearls • Drug-eluting stents are preferred for small vessels given their propensity to restenose but are often unnecessary for larger vessels in excess of 5 mm. • For VAs with a proximal take-off from the left subclavian artery or for those arising from the arch, often transfemoral access is easier and provides better proximal support. • Passing balloon-mounted stents through a tight stenosis can dislodge the stent. If there is excessive resistance, consider predilation with a smaller diameter than the VA balloon prior to placement of the stent.

15 Vertebral Artery Stenting

Case Overview

CASE 15.1 Vertebral Artery Ostium Stenosis Treated with Stenting/Angioplasty: Dual Ostial Balloon

• A 60-year-old female presented to the emergency department with subacute onset of dizziness and vertigo. Her neurological examination was normal. She has a past medical history of squamous cell carcinoma of the tongue that was treated with chemotherapy and radiotherapy several years ago.

• Initial computed tomography (CT) was negative. Further vascular work-up included CT angiogram demonstrated left internal carotid artery (ICA) and left vertebral artery (VA) origin (VAO) stenosis. She underwent left ICA stenting. • Now, she presents for elective left VAO stenting.

Fig 15.1a CT angiogram demonstrating left VAO stenosis.

Fig 15.1b Artist’s illustration of vertebral artery ostial stenosis treated with drug-eluting stent and the dual-balloon angioplasty.

Fig 15.1c Subclavian artery angiogram showing the severe vertebral artery stenosis.

Fig 15.1d Crossing vertebral artery stenosis with microwire.

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Fig 15.1e Balloon-mounted stent deployment.

Fig 15.1f Ostial dual-balloon angioplasty.

Fig 15.1g Successful revascularization of the left vertebral artery.

Video 15.1 Vertebral artery ostial stenosis treated with stenting and dual balloon angioplasty

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15  Vertebral Artery Stenting

Procedure • The patient underwent left VAO stenosis treatment with stenting angioplasty with a drug-eluting stent and ostial dualballoon angioplasty. Patient started dual-antiplatelet therapy (clopidogrel 75 mg and aspirin 325 mg) 7 days prior to the procedure. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 8F sheath. • Cook Shuttle guide catheter (Cook Medical). • 0.035-in Glidewire (Terumo). • 0.014-inch Spartacore 14 wire (Abbott). • Promus Premier 4 x 12 mm drug-eluting stent. • FLASHMINI Ostial System. • 8F AngioSeal percutaneous closure device.

The procedure requires a 6F guide catheter to access the subclavian artery. Subclavian artery access can be obtained from femoral or radial artery. The anatomical location and angulation of the VAO will dictate the approach. After obtaining adequate working views of the VAO and the stent size has been selected, the lesion is crossed with a 0.014-inch wire. A filter is rarely used because of the small caliber of the VA. We recommend to use a drug-eluting stent to reduce the incidence of restenosis. Use of the dual-balloon (FLASH balloon) is optional but strongly recommended. This device has a distal and a proximal balloon. The proximal balloon has a wider diameter. The proximal balloon will flair the proximal end of the stent against the subclavian artery, making reaccess to the stent technically easier in case of stenosis recurrence or the need to access the VA.

Tips, Tricks & Complication Avoidance • VAO stenosis is the result of atherosclerosis and tortuosity of the proximal segment of V1. This tortuosity could give the impression of a shorter stenosis segment. Keep this in mind when selecting stent sizes. It is not uncommon to see after the first stent deployment, the vessel straightened revealing another segment of stenosis uncovered by the initial stent. • While deploying the stent, we recommend the interventionist to hold the stent steady in the adequate place while an assistant is deploying the stent. As the balloon-mounted stent is inflated, it could move and the stenosis missed.

• The wire should remain across the lesion until the procedure is complete to avoid having to regain access and possible move a freshly deployed unstable stent. • In-stent stenosis, stent migration and stent deformation are known long-term complications. All patients require long-term clinical and radiographic follow-up. • Alternatives to the VAO stenting is VA transposition. The VA is anastomosed to the common carotid artery.

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16  Venous Sinus Stenting Jason M. Davies and Leonardo Rangel-Castilla

General Description Idiopathic intracranial hypertension (IIH) has traditionally been treated with shunt placement and weight loss, but mounting evidence has indicated that venous outflow restrictions can contribute to elevated intracranial pressure that can be reversed with stenting. Two types of stenosis exist: intrinsic, in which the size of a segment of the venous sinus is reduced (e.g., from scarring or congenitally), and extrinsic, in which elevated pressures or surrounding structures (e.g., arachnoid granulations) exert pressure on the venous wall that cause it to bow inward. Both stenosis types respond to stenting and the stenting helps to control the IIH symptoms.

Indications Stenting may be considered when there are definite signs and symptoms of intracranial hypertension and evidence of elevated venous pressures. Evaluation includes a lumbar puncture to determine elevated intracranial pressure, an ophthalmology evaluation to assess for visual loss and changes to the optic nerve, and diagnostic venography with pressure sampling along the course of the major dural sinuses to identify hemodynamically significant stenosis. In practice, a pressure gradient of at least 8 mmHg and visual compromise are the strongest indications for stenting.

Neuroendovascular Anatomy The most common locations for venous stenoses associated with symptomatic IIH are in the transverse and sigmoid sinuses. Stenosis of the posterior third of the superior sagittal sinus (SSS) can also cause symptomatology. Because the transverse and sigmoid sinuses are paired structures, it is critical to assess pressure gradients. Often, one side is sufficient for adequate drainage; and, as a corollary to this, when bilateral stenosis is observed, patients often derive relief from unilateral stenting. In practice, we measure pressures in every patient bilaterally starting at the middle SSS and proceeding proximally as follows: middle and posterior SSS; torcula; distal, middle, and proximal transverse sinus; transverse-sigmoid junction; distal, middle, and proximal sigmoid sinus; and jugular vein. In most patients, it is possible to access both sides from a unilateral approach by crossing the torcula with a microcatheter to access the contralateral circulation.

Specific Technique and Key Steps 1. Review of noninvasive imaging studies and the previously performed diagnostic venogram to identify the optimal access route and the site of the pressure gradient. 2. Femoral venous access is obtained, as previously described in Chapter 2, and a 6 French (F) short sheath is placed. 3. A Benchmark (Penumbra) or similar distal access catheter is advanced through the venous system and into the sigmoid sinus (Fig. 16.1, 16.2, Video 16.1, 16.2).

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4. A 3MAX (Penumbra) or similar microcatheter is advanced over a 0.014-inch microwire and pressures are measured to verify the location of the gradient. 5. Once the location of the gradient is established and marked on a roadmap, the soft guide catheter is advanced over the microcatheter, past the location of the stenosis, and the microcatheter and microwire are withdrawn (Video 16.1, 16.2). 6. A 0.018-inch floppy-tipped microwire is backloaded into a selfexpanding open-cell or closed-cell carotid or biliary stent, such as the Zilver (Cook Medical) or the Wallstent (Abbott). 7. The microwire and stent are advanced into the guide catheter and positioned to span the stenosis. Then, unsheathing the stent in position across the stenosis, the guide catheter is withdrawn (Video 16.1, 16.2). 8. The stent is deployed in place across the stenotic region, and the stent and microwire are withdrawn (Fig. 16.1, 16.2, Video 16.1, 16.2). 9. Follow-up runs are obtained to assure patency and good distal flow. 10. Pressure measurements are obtained across the stenotic region to verify that the gradient has improved. 11. The guide catheter, microwire, and microcatheter are withdrawn after all images are determined to be satisfactory. 12. The venous access site is closed with manual compression as the sheath is withdrawn.

Device Selection • Access: – 6F short femoral sheath. – Benchmark or similar 6F distal access system with Berenstein select catheter (Cook Medical). – 0.035-inch angled Glidewire (Terumo). – 3MAX or similar microcatheter. – 0.014-inch microwire (Synchro 2, Stryker). – Pressure transducer. • Stenting: – Self-expanding carotid or biliary flexible (open-cell) stent. – 0.018-inch floppy-tipped microwire.

Pearls • The most worrisome complication of venous sinus stenting is intracranial hemorrhage. We avoid the use of balloons in the venous sinuses to minimize this risk. • Venous valves can make navigating the guide catheter within the sinuses challenging. Using a soft Glidewire is usually sufficient to “feel” one’s way through the valves, but occasionally it can be helpful to have arterial access to obtain a roadmap of the venous system (Video 16.1, 16.2).

16  Venous Sinus Stenting

Case Overview

CASE 16.1 Venous Stenting for Left Transverse Sinus Stenosis

• A 56-year-old female presented with acute chronic severe headaches associated with progressive vision disturbances. She was found to have bilateral papilledema. The rest of the neurological examination was normal. She has a past medical history of obesity. • Magnetic resonance (MR) imaging showed relatively small ventricles. MR venogram suggested stenosis of the left transverse sinus. • Lumbar puncture demonstrated significant elevated intracranial pressure (ICP) (51 cm/ H2O). Her symptoms improved after removing 30 mL of cerebrospinal fluid.

She underwent venous pressures measurement to assess the presence of pressure gradient and the need for venous sinus stenting. The following pressures were found: – Superior sagittal sinus: 29. – Torcula: 28. – Left midtransverse sinus: 31. – Left sigmoid sinus: 9. – Increase pressure gradient across the left transverse/sigmoid junction sinus. –

Fig 16.1a  MR venogram showing left transverse sinus stenosis.

Fig 16.1b  Artist’s illustration of left transverse sinus stenting venoplasty.

Fig 16.1c  Right femoral vein access.

Fig 16.1d  Accessing the left jugular vein using guide catheter (green arrow), intermediate catheter (white arrow), smaller intermediate catheter (red arrow).

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Fig 16.1e  Accessing the intracranial venous sinuses. Guide catheter (green arrow), intermediate catheter (white arrow), smaller intermediate catheter (red arrow).

Fig 16.1f  Stent placement prior to intermediate catheter unsheathing.

Fig 16.1g  Stent deployment.

Fig 16.1h  Significant improvement of the left transverse sinus stenosis.

Video 16.1  Left transverse sinus stenting for sinus stenosis

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16  Venous Sinus Stenting

Procedure • The patient underwent left transverse sinus stenting venoplasty. Dual antiplatelet therapy (clopidogrel 75 mg and aspirin 325 mg daily) was initiated 7 days prior to the procedure. The procedure was performed under conscious sedation and through a right femoral vein approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral venous access. – Micropuncture kit. – 8F sheath. • Neuron MAX 088 guide catheter (Penumbra). • 0.035 exchange length wire. • 5F Sofia intermediate catheter (Microvention). • 3 MAX intermediate catheter (Penumbra). • 0.014-inch Synchro 2 wire (Stryker). • Wallstent 8 x 30 mm (Boston Scientific). • Heparin 5,000 units.

This young female patient was confirmed to have idiopathic intracranial hypertension associated with left transverse sinus stenosis with significant venous pressure gradient. Left side transverse sigmoid sinus stenting could be more challenging than right side transverse sinus. Accessing the left jugular vein could require longer guide and intermediate catheters. The vein valves can be difficult to cross and a stiff wire is necessary (stiff 0.035inch or 0.038-inch wire). The guide catheter is navigated up to the sigmoid sinus, if possible. An intermediate catheter was advanced up to the transverse sinus beyond the stenosis. The stent is then navigated at the stenosis site, the intermediate catheter is then removed (exposing the stent), and the stent deployed.

Tips, Tricks & Complication Avoidance • Venous sinus stenting should be reserved for patients not responding to medical management, continuing to have visual deterioration, and having evidence of venous sinus stenosis with significant pressure gradient. • Only patients with a pressure gradient of 10 mmHg or more are considered candidates for venous sinus stenting. • Potential complications of venous sinus stenting include sinus or cortical draining, vein preformation, thrombosis of the venous system with possible pulmonary embolism, and retroperitoneal hematoma.

• The stent length is selected based on measurements of the stenotic segment. We generally oversize the stent by 2 mm in comparison to the diameter of the normal sinus. • Perform a post-stenting manometry to confirm resolution of pressure gradient and repeat angiography and manometry on patients with recurrence of symptoms after resolution with stenting to evaluate for recurrent stenosis. • Surgical alternatives to pseudotumor cerebri management include ventriculoperitoneal or lumboperitoneal shunt and optic nerve sheath fenestration.

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Case Overview

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CASE 16.2 Venous Stenting for Right Transverse Sinus Stenosis

• A 46-year-old obese female presented with subacute onset of severe headaches, progressive blurry vision, and imbalance. She was found to have bilateral mild-to-moderate papilledema. The rest of the neurological examination was normal. • Magnetic resonance (MR) imaging was essentially normal, except for small ventricles. MR venogram revealed stenosis of the right transverse sinus. • Lumbar puncture demonstrated elevated ICP (46 cm/H2O). Medical treatment (acetazolamide) was initiated with minimal-to-no improvement.

• Patient was offered endovascular treatment of the venous sinus stenosis with stenting venoplasty. • Prior to the stenting venoplasty, venous pressures were measured to assess the presence of pressure gradient and the need for stenting. The following pressures were found: – Superior sagittal sinus: 35. – Torcula: 31. – Right midtransverse sinus: 35. – Right sigmoid sinus: 7. – Increase pressure gradient across the right transverse/sigmoid junction sinus.

Fig 16.2a  MR venogram showing right transverse sinus stenosis.

Fig 16.2b  Artist’s illustration of right transverse sinus stenting venoplasty.

Fig 16.2c  Anteroposterior and lateral transverse sinus venogram demonstrating the stenosis.

Fig 16.2d  Stent deployment. Guide catheter (red arrow) and intermediate catheter (white arrow).

16  Venous Sinus Stenting

Fig 16.2e  Stent deployment.

Fig 16.2f  Significant improvement of the right transverse sinus stenosis.

Video 16.2  Right transverse sinus stenting for sinus stenosis

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III  Extracranial Vessel Angioplasty/Stenting

Procedure • The patient underwent right transverse sinus stenting angioplasty. Dual antiplatelet therapy (clopidogrel 75 mg and aspirin 325 mg daily) was initiated 7 days prior to the procedure. The procedure was performed under conscious sedation and through a right femoral vein approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral venous access. – Micropuncture kit. – 8F sheath. • Neuron MAX 088 guide catheter (Penumbra). • 0.035 exchange length wire • Navien 057 intermediate catheter (Medtronic). • 3 MAX ACE reperfusion catheter (Penumbra). • 0.014-inch Synchro 2 wire (Stryker). • Precise Pro RX Stent 8 x 30 mm (Cordis). • Heparin 4,000 units.

This patient was diagnosed with pseudotumor cerebri (idiopathic intracranial hypertension) associated to right transverse sinus stenosis. Prior to stenting, a venogram with pressures measurement was obtained, demonstrating a significant pressure gradient along the stenosis segment. The guide catheter was navigated up to the sigmoid sinus. An intermediate was advanced up to the transverse sinus beyond the stenosis. The stent was then navigated at the stenosis site, the intermediate catheter was then removed (exposing the stent), and the stent deployed. The use of an intermediate catheter helped the stent advancing through the acute angle of the transverse/sigmoid junction and through the stenosis. The Precise Pro RX stent is a low-profile nitinol stent with autotapering design, allowing preservation of complex vessel angulation.

Tips, Tricks & Complication Avoidance • The largest comprehensive meta-analysis (Leishangthem et al., J Neuroradiol. 2018) of dural venous sinus stenting for medically refractory pseudotumor cerebri suggested that stenting is associated with high technical success (99.5%), low rates of repeated procedures (10%), and low major complications rates (1.5%). • Risk of sinus or cortical vein perforation and resultant intracerebral hemorrhage exists with the manipulation of the wire and guide catheter. Always pay attention to the lateral fluoroscopy view to prevent inadvertent straight sinus access.

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• In the case of sinus or cortical vein perforation, anticoagulation reversal (protamine) follow by rapid balloon inflation are the two initial steps. • Although infrequent, acute thrombosis and progressive stent occlusion are the most common risks. Always perform and immediate poststenting venography to confirm stent patency. In the case of acute thrombosis, mechanical or chemical (glycoprotein IIb/IIIa inhibitors) thrombectomy are employed.

Part IV Acute Stroke Procedures

IV

17 Anterior Circulation Mechanical Thrombectomy (ADAPT)

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18 Anterior Circulation Mechanical Thrombectomy with Stent Retriever

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19 Posterior Circulation Mechanical Thrombectomy

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20 Mechanical Thrombectomy with Intracranial Stenting/Angioplasty

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21 Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty

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22 Intracranial Atherosclerotic Disease— Intracranial Angioplasty

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17  Anterior Circulation Aspiration-Only Mechanical Thrombectomy (ADAPT) Gary B. Rajah and Leonardo Rangel-Castilla

General Description Mechanical thrombectomy has become a standard of care for acute ischemic stroke (AIS) associated with large-vessel occlusion (LVO). Numerous randomized trials have demonstrated the procedure’s effectiveness and therapeutic benefit. The studies include multicenter randomized clinical trial of endovascular treatment for AIS in the Netherlands (MR CLEAN), Endovascular treatment for small core and anterior circulation proximal occlusion with emphasis on minimizing computed tomography to recanalization times (ESCAPE), extending the time for thrombolysis in emergency neurological deficits–intra-arterial (EXTEND-IA), randomized trial of revascularization with solitaire FR device versus best medical therapy in the treatment of acute stroke caused by anterior occlusion circulation large vessel occlusion presenting within 8 hours of symptomatic onset (REVASCAT), and solitaire with the intention for thrombectomy as primary endovascular treatment (SWIFT PRIME). The “2015 AHA/ASA Focused Update of the 2013 Guidelines for Early Management of Patients with AIS” recommends endovascular treatment for patients who meet the relevant criteria. The three mechanical thrombectomy techniques most widely used today include (1) aspiration with the Penumbra system (Penumbra), (2) stent retriever with local aspiration, and (3) a direct first pass aspiration technique (ADAPT). The ADAPT was described in 2013 by Turk et al.1 Large-bore catheters were positioned over the thrombus, and aspiration was applied using a syringe or an aspiration pump. The initial publication reported a 75% success rate, with complete recanalization in 57% of cases. Most recent case series of the ADAPT have reported a success rate of 73.3% with complete recanalization in 90.2% of patients. Newer large-bore trackable aspiration catheters have been partially responsible for this technique’s success. The advantages of ADAPT over stent retrieval is a quicker time to recanalization than is reported in many studies and, with the ADAPT, the thrombus is not crossed prior to its removal, theoretically decreasing the risk of distal emboli.

Indications Mechanical thrombectomy is indicated in AIS because of LVO (occlusion in the internal carotid artery [ICA], middle cerebral artery [MCA] M1 and M2 branches, anterior cerebral artery, or posterior circulation), resulting in a National Institutes of Health Stroke Scale (NIHSS) score > 6. Intervention should be carried out within 6 hours of symptoms, or if the patient has perfusion imaging revealing a large penumbra with little or no ischemic core. If intravenous thrombolysis is contraindicated (e.g., warfarin-treated with a therapeutic international normalized ratio), mechanical thrombectomy is recommended as first-line treatment in LVO.

General Anatomy The ICA normally originates from the common carotid artery (CCA) at the C3-4 or C4-5 vertebral level; it may occur as low as T2 and as high as C1. The petrous portion of the ICA runs forward and medial to the area of the foramen lacerum where it moves superiorly into the cavernous sinus and creates a siphon upon itself before exiting at the distal dural ring. The first branch beyond the distal ring (subarachnoid) is typically the ophthalmic artery, followed by the communicating segment of the vessel. The ICA bifurcates into the first segment of the anterior cerebral artery (A1) and the M1 segment of the MCA. The M1 segment (4–5 mm

diameter) can have accessory and duplicated branches. Perforators going to the basal ganglia (i.e., lenticulostriate arteries) arise from the superior surface of the M1, and care should be taken to avoid inadvertent selection of these with the microwire. The MCA bifurcates (sometimes trifurcates) again near the bottom of the sylvian fissure (this can be variable), and an inferior branch proceeds to the M3 and M4 MCA segments over the temporoparietal region. The superior M2 division moves frontally, supplying the M3 and M4 vessels to Broca’s area as well as the motor area. Vessels in patients with AIS can have severe intracranial atherosclerotic disease, and thrombi can form at these sites as well.

Periprocedural Medications Mechanical thrombectomy procedures are usually performed while the patient is awake and under little or no sedation. Typically, the patient has received intravenous tissue plasminogen actuator (t-PA) 1–2 hours prior to the intervention. No other medication is required for ADAPT intervention.

Specific Technique and Key Steps 1. Most centers require specific times to be recorded for groin access, initial digital subtraction angiography (DSA) runs, microcatheter and device deployment times, and final recanalization times. 2. A 6 French (F) or 8F sheath is inserted in the femoral artery, and femoral angiography is performed. 3. A guide catheter (e.g., Neuron MAX, Penumbra or Shuttle Select, Cook Medical, 80 or 90 cm) is connected to a copilot valve and a continuous heparinized saline flush. An intermediate catheter (e.g., VTK, Cook Medical, 125 cm) over a 0.035-inch or 0.038-inch Glidewire (Terumo) is inserted through the copilot valve into the guide catheter. This construct is navigated up to the aortic arch and into the CCA (Fig. 17.1, 17.2, Video 17.1, 17.2). 4. Cervical carotid artery DSA runs are obtained from the CCA before advancing the guide catheter under roadmap guidance into the ICA (if the ICA diameter is large enough to accommodate the guide catheter; otherwise, the guide catheter is kept at the CCA). 5. Anteroposterior and lateral runs of the cranial portion of the carotid artery are performed, and the site of occlusion is identified (Video 17.1, 17.2). 6. The assembled intermediate large-bore aspiration catheter (e.g., Sofia Plus, MicroVention, Terumo; 64 ACE or 68 ACE, Penumbra) with microcatheter–microwire combination is then inserted into the guide catheter. Under fluoroscopic guidance, the microwire– microcatheter, followed by the intermediate catheter, are advanced to the proximal portion of the thrombus without crossing it (Video 17.1, 17.2). 7. The intermediate catheter is gently advanced to the proximal clot interface, and the microsystem is removed. Aspiration with a pump is performed with tubing connected to the intermediate large-bore aspiration catheter. Aspiration can also be performed using a large syringe. The suction canister is monitored to determine whether the occlusive clot is present (Video 17.1, 17.2). 8. After 4–5 minutes, the aspiration catheter is carefully withdrawn under suction into the guide catheter and out of the patient. Aspiration is accomplished through the guide catheter with two large (30 cc) syringes. The guide catheter is checked for clot after the aspiration catheter is removed (Video 17.1, 17.2).

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IV  Acute Stroke Procedures 9. The large-bore aspiration catheter is flushed on the back table and checked for clot. The microwire/microcatheter is reassembled within the aspiration catheter in the event another pass is needed. 10. Post-thrombectomy DSA runs are performed. If the clot is removed and thrombolysis in cerebral infarction 2b or 3 achieved, the procedure is done and the patient’s neurologic status should be checked (Fig. 17.1, 17.2, Video 17.1, 17.2). If the clot persists (indicated by the clinical examination findings or the presence of clot extravasation), another ADAPT pass is performed. At this point, consideration is given to switching to the stent retriever/aspiration technique. 11. After successful intracranial revascularization and removal of the guide catheter, CCA runs are performed to ensure patency and integrity of the ICA. 12. The guide catheter is removed, and the femoral arteriotomy is closed with an AngioSeal vascular closure device (Terumo). 13. If the patient is stable and more information on collateral supply is needed, a full diagnostic angiogram can be completed.

Device Selection In our practice, the following are the common set-ups and devices used for ADAPT procedures: • 21-gauge micropuncture set (e.g., Cope Mandril wire, Cook Medical; 6F dilator, 6F or 8F sheath; Copilot Valve, Abbott Vascular). • Guide catheter (e.g., Neuron MAX 90 cm or Cook Shuttle 90 cm). • Intermediate sliding catheter (e.g., VTK, 125 cm 5F catheter). • 0.035-inch or 0.038-inch Glidewire 180 cm (e.g., Glidewire Advantage, Terumo). • Large-bore aspiration catheter (e.g., Sofia or Sofia Plus, MicroVention Terumo or 64 or 68 ACE catheter, Penumbra). • 0.027-inch microcatheter (e.g., Velocity, Penumbra; Marksman, Medtronic; Headway 27, MicroVention Terumo). • 0.014- to 0.016-inch microwire (e.g., Synchro 2, Stryker). • Aspiration tubing. • Continuous heparinized saline.

Pearls • Be familiar with distal access aspiration systems, including the aspiration pump. • Understand the patient’s vascular anatomy and thrombus burden.

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• Navigating and delivering the guide catheter through the aortic arch into the CCA in tortuous anatomy can be challenging. After a CCA run, the 0.035- or 0.038-inch wire can be looped into the external carotid artery for extra purchase. • Beware of dissections that can masquerade as thrombus; microinjections can help to identify and differentiate them from one another. Common sites for dissection are the cervical–petrous ICA transition (ICA enters the skull base) and distal dual ring. • Balloon guide catheters can be used (e.g., Cello, Medtronic; FlowGate, Stryker); however, they can be very stiff and require a larger sheath (9F). Some large-bore aspiration catheters will not fit within the sheath. • A gentle “J” curve on the microwire is needed to allow navigation of the cerebral vessels and avoid perforation. • When the triaxial system (large-bore reperfusion catheter, microcatheter, and microwire) is navigated into the proximal part of the thrombus, effort should be made to not cross the thrombus. Take into account any built-up tension in the system while nearing the thrombus (this is a concern because the wire may “jump” and perforate the vessel). • Distal clot migration is more common with a stent retriever, but it is still possible with the ADAPT. • If concern exists or if distal clot migration has occurred, perform an angiographic run. If a smaller vessel is blocked distally, smaller aspiration catheters can be utilized (e.g., 3 MAX ACE catheters, Penumbra). • If tandem occlusions are identified and carotid stenting is needed, we prefer to stent the carotid artery and then treat the intracranial thrombus (see Chapter 20). • Beyond the M2 MCA vessels, the risk versus benefit ratio starts to become unfavorable for intervention. If the initial NIHSS was > 6 and no LVO was found on angiography, it is likely the t-PA dissolved and fragmented the clot. • Always beware of reperfusion hemorrhage. Monitor angiographic runs for contrast extravasation and stagnation.

Reference [1] Turk AS, Spiotta A, Frei D, et al. Initial clinical experience with the ADAPT technique: A direct aspiration first pass technique for stroke thrombectomy. J Neurointerv Surg. 2014;6:231–237.

17  Anterior Circulation Aspiration-Only Mechanical Thrombectomy (ADAPT)

Case Overview

CASE 17.1 Acute Middle Cerebral Artery Occlusion in an Octogenarian: ADAPT

• An 87-year-old female presented to the emergency department with acute onset of left-sided weakness and abnormal speech. Symptoms started 12 hours prior to her arrival. Neurological examination demonstrated severe left right hemiparesis, right facial droop, dysarthria, and left side neglect. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 12. She has a past medical history of hypertension, coronary artery disease, and chronic heart

failure. Patient did not receive intravenous tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. CT angiography demonstrated right middle cerebral artery (MCA) occlusion. CT perfusion demonstrated increased time-to-peak with a large area of preserved volume on the right hemisphere.

Fig 17.1a  CT angiography showing right MCA occlusion.

Fig 17.1b  CT perfusion with increased time-to-peak and preserved volume on left MCA territory.

Fig 17.1c  Artist’s illustration of endovascular mechanical thrombectomy with ADAPT.

Fig 17.1d  Angiography demonstrating complete right MCA occlusion (TICI 0).

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Fig 17.1e  Aspiration catheter positioned at the proximal end of the thrombus.

Fig 17.1f  Complete right MCA revascularization TICI 3.

Fig 17.1g  CT scan 24 h after procedure. Patient with an NIHSS 2.

Video 17.1  ADAPT mechanical thrombectomy for acute MCA occlusion I

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17  Anterior Circulation Aspiration-Only Mechanical Thrombectomy (ADAPT)

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 6F Sofia Plus reperfusion catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 8F AngioSeal percutaneous closure device.

Since the introduction of large-bore aspiration catheter, A Direct Aspiration First Pass Technique (ADAPT) has become an initial technique in most stroke centers. The guide catheter is navigated at the cervical ICA, under road map, the system (intermediate aspiration catheter, microcatheter and microwire) is advanced at the proximal end of the thrombus. We allow the microwire and/ or microcatheter to get into the proximal segment of thrombus to allow the aspiration catheter to engage with the thrombus. We do not cross the thrombus entirely. The microcatheter and microwire are removed and the aspiration catheter connected to the aspiration pump or syringe. Most of the time, the thrombus is removed at first attempt.

Tips, Tricks & Complication Avoidance • Octogenarians have tortuous and elongated vessels. We suggest using the largest guide catheter (Neuron MAX 90 cm) and aspiration catheter (Sofia Plus 131 cm) possible. • We have found Sofia and Sofia Plus reperfusion catheters that has a good combination of distal trackability and a large inner diameter enable to engage with large clot burdens. • ADAPT has been associated with more TICI 3 results and less fragmentation instances as the thrombus is not crossed with a microwire.

• Large bore aspiration catheters could get caught at the ophthalmic artery ostium. We have found this problem less frequent with Sofia catheters. The use of microcatheter with microwire helps getting around this problem. • Our policy is two attempts with ADAPT and if we have not achieved adequate revascularization we then use a stent retriever (Solumbra technique).

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Case Overview

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CASE 17.2 Acute Middle Cerebral Artery in a Young Patient: ADAPT

• A 33-year-old male presented to the emergency department with acute severe right upper and lower extremity weakness and unable to speak; symptoms started 1 hour prior. On neurological examination, the patient was awake, alert, aphasic, with right facial droop, right hemiplegia (0/5), decreased sensation on right upper/lower extremities. His initial NIHSS score was 19. His past medical history significant only for tobacco use.

• Computed tomography (CT) was normal. CT angiography and perfusion showed a left middle cerebral artery (MCA) occlusion (TICI 0) with increased time-to-peak with only a small area of volume lost. Received tissue plasminogen activator (tPA) with minimal improvement.

Fig 17.2a Normal CT. No evidence of hemorrhage or infarction.

Fig 17.2b CT angiogram with complete left MCA occlusion.

Fig 17.2c CT perfusion with increased time-to-peak and preserved volume on more than two-thirds of the left MCA territory.

Fig 17.2d Artist’s illustration of endovascular mechanical thrombectomy of left MCA with ADAPT technique.

17 Anterior Circulation Aspiration-Only Mechanical Thrombectomy (ADAPT)

Fig 17.2e Angiography demonstrating complete left MCA occlusion (TICI 0).

Fig 17.2f Aspiration catheter positioned at the proximal end of the thrombus (red arrow).

Fig 17.2g Almost complete left MCA revascularization (TICI 2b).

Fig 17.2h CT scan 24 h after procedure. Small ischemic infarction on the left basal ganglia. Patient improved significantly; he had an NIHSS score of 3 at discharge.

Video 17.2 ADAPT mechanical thrombectomy for acute MCA occlusion II

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Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. No heparin was administered because the patient received tPA. The procedure was performed under conscious sedation through a right femoral artery approach.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 6F Sofia Plus catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • 8F AngioSeal percutaneous closure device.

A Direct Aspiration First Pass Technique (ADAPT) is an excellent option for mechanical thrombectomy in young patients with minimal vessel tortuosity. A large bore aspiration catheter tracks easily in nontortuous vessels. At times, large bore aspiration catheters navigate over the 0.0014-inch microwire without the need of a microcatheter, achieving faster vessel revascularization. In the current case of a young patient, the aspiration catheter over a microwire was sufficient to approach and remove the thrombus. The reperfusion catheter is connected to an aspiration pump or a large syringe.

Tips, Tricks & Complication Avoidance • Young patients should be treated “aggressively.” Even in the presence of volume lost on CT perfusion, we still recommend mechanical thrombectomy when the volume loss is less than 1/3 of the increased time-to-peak territory. • Young patients (45 years old or younger) usually have relatively straight vessels allowing for a fast guide catheter navigation up in the ICA. A reperfusion catheter over a 0.014-inch microwire could easily reach into the intracranial circulation and thrombus. • An initial ADAPT attempt should be done in all young patients with relatively “straightforward” vasculature.

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• If the patient received tPA, we do not recommend the use of heparin. However, if the patient did not received tPA, we administer 2,500– 4,000 units of heparin. We do not try to achieve an activated clotting time of more than 250. • For ADAPT, the reperfusion catheter is selected based on the size and location of the thrombus. For M1 occlusion, a 6F catheter is adequate; for a small M1 or M2, a 5F catheter; for a distal M2 or M3, a 4F or 3F catheter.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever Gary B. Rajah and Leonardo Rangel-Castilla

General Description Mechanical thrombectomy has become a standard of care for large-vessel occlusion (LVO) with acute ischemic stroke (AIS). Numerous randomized trials have demonstrated the procedure’s efficacy and therapeutic benefit. The two techniques most widely used today include a direct first pass aspiration technique (ADAPT), which was discussed previously in Chapter 16, and stent retriever-based clot retrieval. This chapter will describe the stent-retriever technique. Stent retrievers are available in different sizes and from different manufacturers. Stent retrievers are deployable devices that can be retrieved via their pusher wire. They typically require a 21-gauge or larger catheter for delivery into a vessel. Some are fluoroscopically visible throughout their length (e.g., Trevo, Stryker and Solitaire Platinum, Medtronic). Others are visible only at the tip (Solitaire, Solitaire 2, or Solitaire 3, Medtronic). Stent retrievers yield high recanalization rates in LVO and can be utilized alone, with aspiration, or as a rescue therapy for aspiration-based techniques. Stent retrievers come in a range of sizes from 4 mm to 6 mm × 20 mm and 40 mm. Vessel perforation and reperfusion hemorrhage are the two main concerns related to stent-retriever mechanical thrombectomy. Patient selection can help minimize risk.

Indications Mechanical thrombectomy is indicated in AIS because of LVO (occlusion of the internal carotid artery [ICA] or middle cerebral artery [MCA] branches [M1, M2, M3, and/or M4]) resulting in a National Institutes of Health Stroke Scale (NIHSS) score > 6. Intervention should be carried out within 6 hours of symptoms or if perfusion imaging reveals a large penumbra with little or no ischemic core. We prefer that the patient also has computed tomographic angiography of the head and neck vessels to avoid the discovery of other anomalies during the intervention (i.e., tandem occlusions or ostial stenosis).

Neuroendovascular Anatomy The ICA normally originates from the common carotid artery (CCA) at the C3-4 or C4-5 vertebral level; it may occur as low as T2 and as high as C1. The petrous portion of the ICA runs forward and medial to the area of the foramen lacerum, where it moves superiorly into the cavernous sinus and creates a siphon upon itself before exiting at the distal dural ring. The first branch beyond the distal ring (subarachnoid) is typically the ophthalmic artery, followed by the communicating segment of the vessel. The ICA bifurcates into the A1 (first anterior cerebral artery segment) and M1 segment of the MCA. The M1 (4–5 mm diameter) segment can have accessory and duplicated branches. Perforators going to the basal ganglia (i.e., lenticulostriate arteries) arise from the superior surface of the M1, and care should be taken to avoid inadvertent selection of these with the microwire. The MCA bifurcates (sometimes trifurcates) again near the bottom of the sylvian fissure (this can be variable), and an inferior branch courses to the M3 and M4 segments over the temporoparietal region. The superior M2 division moves frontally supplying the M3 and M4 vessels to Broca’s area as well as the motor area. Vessels in patients with AIS can have severe intracranial atherosclerotic disease (ICAD). Thrombus can form at these sites as well. Furthermore, some patients can become symptomatic from ICAD stenosis because of hypoperfusion and the symptoms can mirror AIS; however, in this situation, thrombectomy is typically not needed.

Surgical or endovascular revascularization with angioplasty or bypass is necessary in this case.

Periprocedural Medications Stent-retriever mechanical thrombectomy procedures are usually performed with the patient awake and under little or no sedation. Typically, the patient has received intravenous tissue plasminogen activator (t-PA), thus, further anticoagulation or antiplatelet therapy is contraindicated. If permanent stent placement is necessary, a loading dose of aspirin and clopidogrel can be administered.

Specific Technique and Key Steps 1. Most centers require specific times to be recorded for groin access, initial digital subtraction angiography (DSA) runs, microcatheter and device deployment times, and final recanalization times. 2. We begin by assembling all of the necessary catheters on the back table and connecting them to heparinized flushes. We lay them out on the angiogram table. The stent-retriever device is selected after reviewing the initial images so the appropriate diameter and length of the device can be determined, depending on the size and location of the clot. 3. Access is obtained via a femoral arteriotomy made with a micropuncture set. A 6 French (F) or an 8F guide sheath is placed. If an 8F sheath is used, a transitional 6F dilator is utilized once the microwire is deemed appropriate in relation to the femoral head seen on fluoroscopy. Then, the 8F sheath is placed. 4. The guide sheath (90 cm) with copilot valve is placed over an intermediate diagnostic catheter (e.g., VTK 125 cm, Cook Medical) and then over a Glide Advantage 180-cm wire (Terumo) and advanced into the CCA. 5. Subtracted runs are taken from the CCA prior to advancing the guide catheter into the ICA (if large enough) under roadmap guidance (Fig. 18.1-18.11, Video 18.1-18.11). 6. Intracranial anteroposterior and lateral runs are performed, and the site of occlusion is identified. 7. The assembled intermediate large-bore aspiration catheter and the microcatheter and microwire combination are then inserted into the guide catheter. Under fluoroscopy, the microwire and microcatheter, followed by the intermediate catheter, are advanced to (but not past) the occlusion site, taking care to account for any built-up tension in the system while nearing the thrombus. Some angiographers cross the lesion with a microwire under suction from the intermediate catheter. In any case, the lesion must be crossed with the microwire and microcatheter. The microwire can then be withdrawn and a microinjection performed to ensure that the vasculature distal to the occlusion is patent (Video 18.1-18.11). 8. The stent-retriever device is then appropriately sized for the vessel. Typically, a 4-mm device is sufficient for M1 and beyond. Larger devices can be selected for larger clots. 9. The device is pushed into the rotating hemostatic valve and back flushed. Then, it is loaded into the microcatheter. Fluoroscopy should be utilized to push the device beyond the fluoro-save. The catheter is pinned at the hub, and the device is pushed to the end of the catheter and beyond the clot. The ideal landing zone for the retriever is to have the clot at its mid to proximal area (Fig. 18.118.11, Video 18.1-18.11).

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IV  Acute Stroke Procedures 10. The stent retriever is deployed by holding the device wire and removing the microcatheter. This maneuver has to be performed carefully and might involve a learning curve. The goal is to keep the device in place while the microcatheter is removed. After 3 minutes of deployment, some angiographers perform microinjections to assess for recanalization. The microcatheter is removed, now pinning the stent. The intermediate large-bore aspiration catheter is turned to suction after 3–5 minutes, and the stent retriever is slowly withdrawn into the intermediate catheter (Video 18.1-18.11). 11. The stent retriever is inspected for clot. Final runs are obtained to determine whether contrast extravasation is present, indicating that another pass with the retriever is needed. The intermediate catheter is also withdrawn under suction and inspected for clot. The guide catheter should be aspirated with two large 30-mL syringes. 12. The microwire/microcatheter is reassembled within the aspiration catheter in the event that another pass is needed. 13. Post-thrombectomy DSA runs are performed. If the clot has been removed and a thrombolysis in cerebral infarction (TICI) grade of 2b or 3 is achieved, the procedure is done, and the patient’s neurologic status should be checked. If the clot persists, consideration is given to making another pass (Video 18.1-18.11). 14. CCA runs are performed after the removal of the guide catheter. A groin run is also performed, if not already completed, to determine eligibility for a closure device (e.g., AngioSeal, Terumo). 15. If the patient is stable and more information on collateral supply is needed, a full diagnostic angiogram can be completed.

Device Selection In our practice, the following are the common set-ups and devices used for stent-retriever mechanical thrombectomy: • 21-gauge micropuncture set, Cope Mandril wire (Cook Medical), 6F or 8F sheath, 6F dilator. • Guide catheter (e.g., Neuron MAX, Penumbra or Flexor Shuttle, Cook Medical). • Intermediate diagnostic catheter (e.g., VTK 125 cm 5F catheter). • Glide Advantage 0.035-inch wire 180 cm. • Large-bore aspiration catheter (Sofia or Sofia Plus, MicroVention). • 0.027-inch microcatheter (e.g., Velocity, Penumbra; Headway, MicroVention; Marksman, Medtronic). • 0.014-inch microwire (e.g., Synchro 2 Standard or soft wire, Stryker). • Suction tubing or large syringe. • Continuous heparinized saline flush. • Stent-retriever device (e.g., Trevo or Solitaire).

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Pearls • The most difficult part of the initial process can be delivering the guide catheter into the CCA in tortuous anatomy (Fig. 18.5, 18.7, Video 18.5, 18.7). After a CCA run, the 0.035-inch or 0.038-inch wire can be looped into the external carotid artery for extra purchase. • When navigating past a thrombus, use caution and knowledge of anatomy to ensure that you stay within a vessel even though it may not fill on subtracted images. Native issues can also be useful. This will help avoid perforations. • A gentle “J” curve is needed on the microwire to allow navigation of the cerebral vessels and avoid vessel perforation. • Beware of dissections that can masquerade as thrombus. Microinjections can help discern the thrombus from dissections. The skull base and distal dual ring are common locations for dissections. • Always beware of reperfusion hemorrhage; monitor angiographic runs for contrast extravasation and stagnation. • Balloon guide catheters (BGCs) can be used (e.g., Cello, ev3); however, they can be very stiff and require a larger sheath (9F). Some large-bore aspiration catheters will not fit within the BGC (Fig. 18.2, 18.3, Video 18.2, 18.3). • Distal clot migration is possible with ADAPT as well as stent retriever techniques. If concerned, perform a run. If a smaller vessel is blocked distally, a smaller aspiration catheter can be utilized. • If tandem occlusions are identified and carotid stenting is needed, we prefer to stent the carotid artery and then treat the intracranial thrombus during the same procedure (see Chapter 20). The guide catheter can be advanced past the stent if possible prior to stent retriever thrombectomy to avoid disturbing the newly placed carotid stent. • Beyond the M2 vessels, the risk-versus-benefit ratio starts to become unfavorable for intervention. If the initial NIHSS score was > 6 and no LVO was found on the angiogram, it is likely that the t-PA broke up the clot. • As mentioned, reperfusion hemorrhage and vessel perforation are the two main concerns associated with stent-retriever mechanical thrombectomy. If a BGC is being used, it can be inflated temporarily to treat reperfusion hemorrhage. If perforation is encountered on microinjection prior to clot removal, resheath the device and allow the thrombus to palliate the hemorrhage.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Case Overview

CASE 18.1 Acute Middle Cerebral Artery Occlusion: Solumbra Technique

• A 75-year-old female presented to the emergency department at 7 a.m. with acute onset of left-sided weakness and abnormal speech. She was seen normal the night before (wake-up stroke). Neurological examination demonstrated severe left right hemiparesia, dysarthria, and left side neglect. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 11. She has a past medical history of

hypertension, chronic heart failure, and pancreatic cancer. Patient did not receive intravenous tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. CT angiography demonstrated right middle cerebral artery (MCA) occlusion. CT perfusion demonstrated increased time-to-peak with a large area of preserved volume on the right hemisphere.

Fig 18.1a  CT angiography showing right MCA occlusion.

Fig 18.1b  CT perfusion with increased time-to-peak and preserved volume on right MCA territory.

Fig 18.1c  Artist’s illustration of endovascular mechanical thrombectomy of MCA using Solumbra technique.

Fig 18.1d  Angiography demonstrating complete right MCA occlusion (TICI 0).

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Fig 18.1e  Microcatheter (arrow) positioned distal to the thrombus.

Fig 18.1f  Stent Retriever (red arrows) and aspiration catheter in the near proximity (white arrow).

Fig 18.1g  Complete right MCA revascularization (TICI 3).

Fig 18.1h  CT scan 24 h after procedure. Patient with an NIHSS of 2.

Video 18.1  SOLUMBRA mechanical thrombectomy for acute MCA occlusion

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18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 6F Sofia Plus aspiration catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 20 mm Solitaire stent retriever (Medtronic). • 8F AngioSeal percutaneous closure device.

The Solumbra technique involves the use of a stent retriever in combination with a large bore aspiration catheter. The thrombus is crossed with microwire/microcatheter, an angiography injection through the microcatheter is obtained to confirm adequate location distal to the thrombus. The microwire is exchanged for the stent retriever and deployed across the thrombus, the microcatheter is then removed entirely. After 5 minutes (to allow thrombus integration with ), the reperfusion catheter under aspiration (pump or syringe) is navigated as close as possible to the thrombus and the stent retriever is removed. At times, the stent retriever will not come out because of the large diameter of the thrombus and the aspiration catheter and stent retriever have to be removed as one unit. The most common stent retriever size used for MCA artery occlusion is 4 x 30 mm or 4 x 40 mm.

Tips, Tricks & Complication Avoidance • It is important to have a large guide catheter in the cervical internal carotid artery (ICA) to easily accommodate a 6F aspiration catheter. The guide catheter can be a balloon guide catheter. • The Solumbra technique requires a three-axial system (large bore aspiration catheter, microcatheter (0.027-inch and microwire). Assemble and advance them all together as a unit until the thrombus is reached. • If the large bore aspiration catheter gets caught in the ophthalmic artery, keep advancing the microcatheter and microwire further until

the thrombus is crossed. Once the stent retriever is advanced, it can be used as extra support for the reperfusion catheter to cross the ophthalmic ICA segment. • Do a gentle contrast injection when performing the angiography run to avoid vessel perforation. • If the vessel remains occluded after the first attempt, confirm thrombus length and adequate coverage, try a larger aspiration catheter, and advance the aspiration catheter further distally over the stent retriever.

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Case Overview

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CASE 18.2 Acute Internal Carotid Artery Bifurcation Occlusion: Solumbra technique with balloon guide catheter

• A 61-year-old female presented to the emergency department with acute onset of left-sided weakness. She was seen normal 12–13 h prior to her arrival. On neurological examination she was awake, confused, with dysarthria, left hemianopsia, left hemiparesia, left facial palsy, and left-side neglect. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 18. She has a past medical history of diabetes, chronic heart failure, and atrial fibrillation. Her medications included

aspirin, coumadin, and metformin. Patient was out of the window for intravenous tissue plasminogen activator (tPA) administration. • Computed tomography (CT) was normal. CT angiography demonstrated right internal carotid artery (ICA) bifurcation occlusion. CT perfusion demonstrated increased time-to-peak with preserved volume on right hemisphere.

Fig 18.2a  CT angiography showing complete right ICA bifurcation occlusion.

Fig 18.2b  CT perfusion with increased time-to-peak and preserved volume on right ICA territory.

Fig 18.2c  Artist’s illustration of endovascular mechanical thrombectomy of ICA bifurcations using Solumbra technique and balloon guide catheter.

Fig 18.2d  Anteroposterior and lateral angiography demonstrating complete right ICA occlusion (TICI 0).

18 Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.2e Microcatheter (arrow) positioned distal to the thrombus.

Fig 18.2f Solitaire Platinum stent retriever deployed (red arrows) and the aspiration catheter in the near proximity (white arrow).

Fig 18.2g Complete right MCA revascularization (TICI 3).

Fig 18.2h Magnetic resonance imaging scan 24 h after procedure. Patient with an NIHSS of 1 at discharge.

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IV  Acute Stroke Procedures Video 18.2  SOLUMBRA mechanical thrombectomy for acute ICA occlusion

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 9F sheath. • 0.035-inch Glidewire. • Concentric balloon guide catheter (Stryker). • 6F Sofia Plus aspiration catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 6 x 30 mm Solitaire Platinum stent retriever (Medtronic). • 8F AngioSeal percutaneous closure device.

Occlusions of the ICA bifurcation can be challenging as the thrombus occludes the ICA, the middle cerebral artery (MCA), and anterior cerebral artery (ACA). Ideally, the thrombus has to be removed as a whole and with one first attempt. To achieve this, a balloon guide catheter and a large stent retriever were used. Balloon guide catheter created flow arrest and decreased the risk of thrombus fragmentation. A large stent retriever (6 x 40 mm) will capture a larger thrombus, as in this current case. Even though the thrombus occludes the ACA, most of the thrombus is at the MCA, therefore the stent retriever is deployed from the MCA down to the ICA. Inflate the balloon guide catheter to create flow arrest, cross the thrombus and deploy the stent retriever, advance the aspiration catheter to the proximity of the thrombus under aspiration (pump or syringe), and while still under flow arrest, remove the aspiration catheter together with the stent retriever and thrombus.

Tips, Tricks & Complication Avoidance • Advance the balloon guide catheter into the cervical ICA as distal as possible. • Inflate and deflate the balloon to check patency and adequate artery occlusion. Do not overinflate the balloon as this could dissect the artery. • Do not inflate the balloon until you are ready to cross the thrombus and deploy the stent retriever.

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• On the post-thrombectomy angiography run, pay attention to the MCA and ACA territories and look for possible distal thrombus fragmentation. It is not uncommon to focus only on the MCA territory and miss distal ACA occlusions. • If revascularization is not achieved with one pass, the process can be repeated with the same device 3–5 times using the same steps. • Special attention should be paid to clean the aspiration catheter and the stent from any thrombus/debris before reusing.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Case Overview

CASE 18.3 Acute Internal Carotid Artery Terminus Occlusion: Balloon Guide Catheter

• A 71-year-old female presented to the emergency department after loss of consciousness, right-sided weakness, and inability to speak. She was seen normal 2 h prior to her arrival. On neurological examination, she was somnolent, confused, not following commands, with right hemiparesis, left gaze deviation, right facial palsy, and right-side neglect. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 19. She has a past medical history of hypertension, chronic heart failure, and atrial fibrillation. The patient was taking

coumadin but discontinued it 4 months prior for unknown reasons. Patient received tissue plasminogen activator (tPA) with minimal improvement. • Computed tomography (CT) was normal. CT angiography demonstrated left internal carotid artery (ICA) bifurcation occlusion. CT perfusion demonstrated increased time-to-peak with preserved volume on left hemisphere, prominently on a distal middle cerebral artery (MCA) branch.

Fig 18.3a  Neck CT angiography showing cervical ICA occlusion.

Fig 18.3b  Head CT angiography showing complete left ICA occlusion (red arrows pointing at the absent ICA).

Fig 18.3c  CT perfusion with increased time-to-peak and preserved volume on left ICA territory and distal MCA branch.

Fig 18.3d  Artist’s illustration of endovascular mechanical thrombectomy of ICA terminus with balloon guide catheter, aspiration, and stent retriever.

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Fig 18.3e  Lateral angiography demonstrating complete cervical ICA occlusion (TICI 0).

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Fig 18.3f  Balloon guide catheter.

Fig 18.3g  Aspiration catheter advancing along the cervical ICA.

Fig 18.3h  Balloon guide and aspiration catheters.

Fig 18.3i  Stent retriever (red arrow) and reperfusion catheter (white arrow).

Fig 18.3j  Complete ICA revascularization.

Fig 18.3k  CT scan 24 h after procedure. Patient with an NIHSS of 1 at discharge.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever Video 18.3  Direct aspiration and SOLUMBRA mechanical thrombectomy for acute ICA occlusion

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 9F sheath. • 0.035-inch Glidewire. • Concentric balloon guide catheter (Stryker). • 6F Sofia Plus aspiration catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 40 mm Solitaire stent retriever (Medtronic). • 8F AngioSeal percutaneous closure device.

The current patient presents with complete acute ICA occlusion. Based on CT angiogram, the thrombus is located at some point between the cervical ICA bifurcation and the cavernous ICA, just before the ICA terminus. There is some collateral flow from the contralateral ICA into the left MCA, through a patent anterior cerebral artery. The balloon guide catheter is advanced into the cervical ICA. The balloon is inflated to create flow arrest and a large bore reperfusion catheter alone under aspiration is advanced as distally as possible (usually at petrous ICA). The rest of the cavernous ICA thrombus is removed with Solumbra technique.

Tips, Tricks & Complication Avoidance • We strongly recommend the use of balloon guide catheter in complete ICA occlusions. Distal embolization can be minimized with the use of a balloon guide catheter to produce temporary flow arrest during mechanical thrombectomy attempts. • Cervical carotid revascularization is indicated in patients with National Institutes of Health Stroke Scale score (NIHSS) of 2 or more and in patients with poor collateral supply or in those with a coexistent intracranial occlusion.

• Collateral circulation should be carefully considered to prevent unnecessary revascularization of proximal carotid occlusion. • Systemic anticoagulation with intravenous heparin is recommended to prevent acute reocclusion and minimize the risk of procedurerelated embolic events.

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Case Overview

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CASE 18.4 Acute Internal Carotid Artery and Middle Cerebral Artery Occlusion: Thrombus Migration

• A 56-year-old male presented to the emergency department with acute onset of right-sided weakness and unable to speak. He was seen normal 1 hour prior to his arrival. On neurological examination he was awake, confused, with right hemiparesis, left gaze deviation, right facial palsy, and right-side neglect. His initial National Institutes of Health Stroke Scale score (NIHSS) was 16. He has a past medical history of hypertension. Patient received tissue plasminogen activator (tPA) and had minimal clinical improvement.

• Computed tomography (CT) was normal. CT angiography demonstrated left internal carotid artery (ICA) terminus occlusion. CT perfusion demonstrated increased time-to-peak with preserved volume on left hemisphere, prominently on a distal middle cerebral artery (MCA) branch.

Fig 18.4a  CT perfusion with increased time-to-peak and preserved volume on left hemisphere.

Fig 18.4b  Artist’s illustration of endovascular mechanical thrombectomy of ICA bifurcation to MCA migration thrombus with aspiration and stent retriever.

Fig 18.4c  Anteroposterior and lateral angiography demonstrating that the thrombus had migrated from ICA terminus to MCA (TICI 0).

Fig 18.4d  Balloon guide and aspiration catheter.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.4e  Crossing thrombus with microcatheter.

Fig 18.4f  Stent retriever deployed (red arrows) and aspiration catheter (white arrow).

Fig 18.4g  Complete MCA revascularization.

Video 18.4  Balloon guide catheter and SOLUMBRA mechanical thrombectomy for acute ICA occlusion

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Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 9F sheath. • 0.035-inch Glidewire. • Concentric balloon guide catheter (Stryker). • 6F Sofia Plus aspiration catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 30 mm Trevo stent retriever (Stryker). • 8F AngioSeal percutaneous closure device.

It is not uncommon to see thrombus fragmentation after tPA administration. In the current case, initial CT angiogram showed ICA occlusion; angiogram prior to the intervention showed that the thrombus had migrated to the MCA. Even though MCA occlusion is technically less challenging than ICA occlusion, a fragile thrombus could fragment again and travel further distal. Solumbra under flow arrest was the technique used in this case obtaining TICI 3 revascularization after the first attempt.

Tips, Tricks & Complication Avoidance • Periprocedural thrombus fragmentation is a relevant risk in endovascular stroke treatment. Younger age, easy-to-retrieve thrombi, and bridging thrombolysis may be risk factors for periprocedural thrombus fragmentation. • If migration or fragmentation of thrombus have occurred, establish with exactitude the clot burden prior to the stent retriever device

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selection. Also, analyze meticulously all distal vessels looking for small fragments that might require mechanical thrombectomy or intra-arterial tPA. • The use of balloon guide catheter has been shown to reduce the incidence of fragmentation and thrombus migration.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Case Overview

CASE 18.5 Acute Middle Cerebral Artery Occlusion: Direct Cervical Carotid Artery Access

• A 94-year-old female presented to the emergency department after she was found down on her bedside by her family at 7 a.m. She was seen normal the night before. On neurological examination, she was awake, confused, aphasic, and with right hemiparesis. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 16. She has a past medical history of hypertension, chronic heart failure, and atrial fibrillation. Patient did not receive tissue plasminogen activator (tPA).

• Computed tomography (CT) was normal. Head CT angiography demonstrated middle cerebral artery (MCA) occlusion. CT perfusion demonstrated increased time-to-peak with preserved volume on left MCA artery. Neck CT angiography also showed severe cervical carotid artery tortuosity.

Fig 18.5a  Neck CT angiography showing severe cervical carotid artery tortuosity.

Fig 18.5b  Head CT angiography showing left MCA occlusion.

Fig 18.5c  CT perfusion with increased time-to-peak and preserved volume on left MCA territory.

Fig 18.5d  Artist’s illustration of endovascular mechanical thrombectomy of left MCA through direct cervical carotid access.

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Fig 18.5e  Anteroposterior and lateral angiography demonstrating cervical ICA tortuosity.

Fig 18.5f  Obtaining direct carotid access.

Fig 18.5g  Direct carotid access obtained with a 6F sheath.

Fig 18.5h  Left MCA (M2) occlusion.

Fig 18.5i  Crossing thrombus with microcatheter (red arrow) and aspiration catheter (white arrow) proximal to thrombus.

Fig 18.5j  Complete left MCA (M2) revascularization.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.5k  CT scan 24 h after procedure. NIHSS of 0.

Video 18.5  Direct carotid artery access for acute MCA occlusion mechanical thrombectomy

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Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was attempted under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered. After multiple transfemoral attempts, the patient was intubated and a direct common carotid artery access under ultrasound was obtained.

Device List

Device Explanation

• Transfemoral approach. – Femoral artery access. ◦ Micropuncture kit (2). ◦ 8F sheath. – 0.035-inch Glidewire. – 0.038-inch stiff Glidewire. – Neuron MAX 088 guide catheter (Penumbra). – Vitek 125-cm long catheter (Cook Medical). – 6F Sofia Plus aspiration catheter (Microvention). – 0.027-inch velocity microcatheter (Penumbra). – 0.014-inch Synchro 2 microguidewire (Stryker). – 8F AngioSeal percutaneous closure device.

Elderly patients have dilated noncompliant aortic arch and carotid artery tortuosity secondary to atherosclerosis. It is important to analyze the CT angiography prior to the intervention. In the current case after multiple attempts with large catheters, sliding catheters and glidewires, we proceeded with direct carotid access. Using ultrasound, the common carotid is identified and accessed percutaneously. A 6F sheath is inserted and carotid angiogram performed to rule out any complications. A large bore reperfusion catheter (6F) is inserted over a microcatheter and microwire. We then proceed with mechanical thrombectomy using an ADAPT or Solumbra technique.

• Direct Carotid Access. – 6F sheath. – 6F Sofia Plus aspiration catheter (Microvention). – 0.027-inch velocity microcatheter (Penumbra). – 4 x 20 mm Solitaire Stent Retriever (Medtronic). – 0.014-inch Synchro 2 microguidewire (Stryker).

Tips, Tricks & Complication Avoidance • It is not uncommon for elderly patients to have severe arch and great vessel tortuosity. Look at the CT angiogram prior to the endovascular procedure to get an idea of the vessel anatomy. • After several failed transfemoral attempts, do not hesitate to get direct carotid access. Under ultrasound guidance, obtain access into the common carotid artery with a microneedle (21-gauge), gently past the microwire and dilator before inserting a larger sheath. A 6F sheath is big enough to accommodate a large bore aspiration catheter.

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• Make a small skin incision prior to advancing the 6F sheath to allow a smooth sheath insertion. • Once access has been established, proceed with the mechanical thrombectomy. • After the procedure is completed, hold manual pressure over the carotid artery for 20 to 25 min or longer if tPA was used.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Case Overview

CASE 18.6 Acute Middle Cerebral Artery Occlusion: Mechanical Thrombectomy and Intracranial Angioplasty

• A 76-year-old female while awaiting orthopedic surgery in the hospital became hemiplegic and aphasic. She was seen normal 2 h prior to her neurological change. On neurological examination, she was awake, confused, globally aphasic, and with right hemiparesis. Her initial National Institutes of Health Stroke Scale score (NIHSS)

was 18. She has a past medical history of hypertension and atrial fibrillation. Patient did not receive tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. Head CT angiography demonstrated left middle cerebral artery (MCA) occlusion. A CT perfusion was not obtained.

Fig 18.6a  Anteroposterior and lateral angiography showing complete occlusion of left MCA.

Fig 18.6b  Artist’s illustration of endovascular mechanical thrombectomy and angioplasty of left MCA occlusion and stenosis.

Fig 18.6c  Cranial anteroposterior angiography demonstrating complete left MCA occlusion (TICI 0).

Fig 18.6d  Obtaining access into left MCA. The reperfusion catheter is stuck at the ophthalmic artery (arrow).

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Fig 18.6e  A second microwire (arrow) was used to navigate the reperfusion catheter into the MCA.

Fig 18.6f  Left MCA stenosis more evident after thrombectomy.

Fig 18.6g  Intracranial balloon angioplasty.

Fig 18.6h  Improvement of MCA stenosis.

Fig 18.6i  CT scan 24 h after procedure. NIHSS of 0.

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18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever Video 18.6  SOLUMBRA mechanical thrombectomy and submaximal angioplasty for acute MCA occlusion

Procedure • The patient underwent emergent cerebral angiography, endovascular mechanical thrombectomy, and submaximal angioplasty. The procedure was performed under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 6F Sofia Plus aspiration catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 2 x 10 mm Gateway intracranial balloon angioplasty (Stryker). • 8F AngioSeal percutaneous closure device.

In the current case, the patient presented with acute left MCA occlusion presumable to cardiac embolism. Once the mechanical thrombectomy was performed, the artery opened partially, revealing intracranial atherosclerosis (ICAD). Through the same reperfusion catheter, an intracranial balloon was navigated up to the stenosis and a submaximal angioplasty was performed. The large bore aspiration catheter was getting stuck on the ophthalmic artery, a second wire was used for extra support to allow the aspiration catheter to pass the ophthalmic artery. After the submaximal angioplasty, another angiography run was obtained to rule distal occlusion and reassess flow through the intracranial stenosis.

Tips, Tricks & Complication Avoidance • Patients with underlying ICAD at the site of arterial occlusion tend to be refractory to thrombectomy treatment, resulting in a  lower recanalization rate and more frequent re-occlusion, which might be associated with poor outcome. • Once intracranial stenosis at the site of arterial occlusion is suspected, the stenosis have to be differentiated from partial thrombus versus true ICAD. A second mechanical thrombectomy can be attempted; if there is no improvement of the stenosis, most likely it is related to preexisting ICAD.

• When selecting intracranial balloon diameter, we usually do 70%– 80% of the normal artery diameter. For ICAD associated with acute thrombus, we use a balloon 50%–60% of the normal artery diameter as the plaque could be unstable and the angioplasty could brake the plaque causing further embolism. • Close clinical, and imaging follow-up is necessary as the ICAD lesion might need a second submaximal angioplasty with a larger balloon or stenting. • Patients will require dual-antiplatelet therapy after the mechanical thrombectomy.

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Case Overview

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CASE 18.7 Acute Middle Cerebral Artery Occlusion: Use of Multiple Parallel Wire for Severe Carotid Artery Tortuosity

• A 86-year-old male presented to the emergency room with difficulty talking and unable to move his right side. He was seen normal 4 h prior to his arrival. On neurological examination, he was awake, alert, confused, aphasic, and right hemiparesis. His initial National Institutes of Health Stroke Scale score (NIHSS) was 14. He has a past medical

history of hypertension, diabetes, and coronary artery disease. Patient did not receive tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. Head CT angiography demonstrated left middle cerebral artery (MCA) occlusion. Neck CT angiography suggested left internal carotid artery (ICA) tortuosity.

Fig 18.7a Angiography showing left ICA tortuosity and complete occlusion of left MCA.

Fig 18.7b Artist’s illustration of endovascular mechanical thrombectomy left MCA occlusion using the parallel guidewire for carotid artery access.

Fig 18.7c Prepping the ZigiWire system.

Fig 18.7d Guide catheter at the aortic arch (not shown). First parallel wire advance into the let ICA.

18 Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.7e First and second parallel wires advance into the let ICA.

Fig 18.7f First, second, and third parallel wires advance into the left ICA.

Fig 18.7g Guide catheter (red arrow) advanced into common carotid artery and reperfusion catheter (white arrow) advance into ICA.

Fig 18.7h Guide catheter was navigated into left ICA for more support.

Fig 18.7i Stent retriever (red arrow) and reperfusion catheter (white arrow) in adequate position.

Fig 18.7j Complete left MCA revascularization.

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IV  Acute Stroke Procedures Video 18.7  Multiple parallel glidewire (Zigiwire) for difficult intracranial access during stroke intervention

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 8F sheath. • 0.035-inch Glidewire. • 0.035-inch stiff Glidewire. • 0.038-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • Vitek catheter 125-cm long (Cook Medical). • ZigiWire access Guidewire system (Vascular solutions). • 6F Sofia Plus reperfusion catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 40 mm Solitaire stent retriever (Medtronic). • 8F AngioSeal percutaneous closure device.

This patient had severe tortuosity of the proximal segment of the ICA causing significant glidewire kickback preventing advancing the guide catheter. The multiple parallel wire (ZigiWire) uses consecutive delivery of three small-diameter (0.014-inch) guidewires that are progressively advanced in parallel to secure support-wire access. The progressive construction of a large wire from smaller wires prevents “kickback” force from a single larger guidewire, allowing stable distal access. Once the guide catheter is advanced into the ICA, the ZigiWire is removed and proceed with the mechanical thrombectomy. Keep track of the guide catheter location as it could herniate inadvertently into the aortic arch during the intracranial thrombectomy.

Tips, Tricks & Complication Avoidance • The ability to traverse an anatomically challenging and complex arch is paramount to the success of any neuroendovascular procedure. With age, the aortic arch and great vessels become elongated, calcified, and less compliant. The multiple parallel wire (ZigiWire) is an organized guidewire system that uses consecutive delivery of three smalldiameter (0.014-inch) guidewires that are progressively advanced in parallel to secure support-wire access.

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• The tip of each individual wire should be shaped according to the angle necessary to get access from the common carotid artery into ICA. • Alternative to the ZigiWire is the use of multiple (two or three) independent 0.018-inch (e.g., V-18 [Boston Scientific]) wires in a similar fashion, advancing one wire at a time to avoid the kickback from a single large (0.035-inch) wire.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Case Overview

CASE 18.8 Acute Middle Cerebral Artery Occlusion: EmboTrap Device

• A 64-year-old female presented to the emergency room unable to move her left side. She was seen normal 3 h prior to her arrival. On neurological examination, she was awake, alert to person only, confused, with slurred speech and left hemiparesis. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 11. She has a past medical history of hypertension, rheumatic heart disease, mechanical aortic valve, and chronic heart failure. Patient stopped

her anticoagulation a few weeks prior for unknown reasons. Patient received tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. CT angiography demonstrated right middle cerebral artery (MCA) occlusion. CT perfusion showed increased time-to-peak with preserved volume on right MCA territory.

Fig 18.8a  CT angiography showing complete occlusion of right MCA.

Fig 18.8b  CT perfusion with increased time-to-peak and preserved volume on right MCA territory.

Fig 18.8c  Artist’s illustration of endovascular mechanical thrombectomy right MCA occlusion using EmboTrap device.

Fig 18.8d  Right MCA occlusion.

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Fig 18.8e  Loading EmboTrap device into the triaxial system (balloon guide catheter, aspiration catheter, and microcatheter).

Fig 18.8f  Anteroposterior view of the EmboTrap device deployed.

Fig 18.8g  Lateral view of the EmboTrap device deployed.

Fig 18.8h  Aspiration catheter over the EmboTrap device.

Fig 18.8i  Immediate revascularization of right MCA. EmboTrap device still in situ.

Fig 18.8j  Complete revascularization of right MCA after mechanical thrombectomy.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.8k  Thrombus.

Video 18.8  Balloon guide catheter and Embotrap mechanical thrombectomy for acute MCA occlusion

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 9F sheath. • 0.035-inch Glidewire. • 9F concentric balloon guide catheter (Concentric Medical). • Vitek catheter 125 cm (Cook Medical). • 6F Sofia Plus reperfusion catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • EmboTrap stent retriever 5 x 21 mm (Cerenovus). • 8F AngioSeal percutaneous closure device.

In the present case of acute MCA occlusion, a mechanical thrombectomy using the Solumbra technique and flow arrest with balloon guide catheter were used successfully. The EmboTrap device is a dual-layer stent retriever, engineered with articulating petals, and a distal capture zone for trapping, retaining, and removing various clot types. Once the stent retriever has been deployed, never attempt to advance the device directly as it could damage the vessel endothelium. If the clot was not entirely covered, recapture and remove the device, and advance the microcatheter over the microwire.

Tips, Tricks & Complication Avoidance • ARISE II (Analysis of Revascularization in Ischemic Stroke with EmboTrap) was a single-arm, prospective, multicenter study, comparing the EmboTrap device to a composite performance goal criterion derived using a Bayesian meta-analysis from the pivotal SWIFT (Solitaire device) and TREVO 2 (Trevo device) trials. 227 patients were enrolled and treated with the EmboTrap device. The primary efficacy end point (mTICI ≥ 2b within three passes) was achieved in 80.2% (P value, < 0.0001). The rate of first pass (mTICI ≥ 2b following a single pass) was 51.5%. The primary safety end point composite rate

of symptomatic intracerebral hemorrhage or serious adverse device effects was 5.3%. Functional independence and all-cause mortality at 90 days were 67% and 9%, respectively. • Recent studies have shown the risk of distal embolization can be altered with improved stent retriever design. When encountering fragment-prone clots, EmboTrap thrombectomy may lower the risk of distal embolization.

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Case Overview

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CASE 18.9 Acute Bilateral Anterior Cerebral Artery Occlusion: Solumbra Technique

• A 69-year-old male presented to the emergency room with weakness on his right upper and lower extremities as well as his left lower extremity, slurred speech and confusion. He was seen normal 6 h prior to his arrival. On neurological examination he was awake, confused, with slurred speech, right hemiparesis and left lower extremity weakness. His initial National Institutes of Health Stroke Scale score (NIHSS) was 20. He has a past medical history of hypertension and

alcohol abuse. Patient did not receive tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. CT angiography demonstrated right and left anterior cerebral artery (ACA) occlusion. CT perfusion showed increased time-to-peak with preserved volume on right and left ACA territory.

Fig 18.9a  CT angiography showing complete right and left ACA.

Fig 18.9b  CT perfusion with increased time-to-peak and preserved volume on right and left ACA territory.

Fig 18.9c  Artist’s illustration of endovascular mechanical thrombectomy of left azygous ACA occlusion with Solumbra technique.

Fig 18.9d  Anteroposterior and lateral angiogram showing bilateral ACA occlusion.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.9e  Accessing distal ACA with microcatheter (red arrow) and reperfusion catheter (white arrow).

Fig 18.9f  Stent retriever (4 x 40 mm Solitaire Platinum) before and after deployment.

Fig 18.9g  Complete revascularization of left azygous ACA after mechanical thrombectomy.

Video 18.9  Mechanical thrombectomy for acute azygous anterior cerebral artery occlusion

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Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. 4,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 9F sheath. • 0.035-inch Glidewire. • 9F concentric balloon guide catheter (Concentric Medical). • Vitek catheter 125 cm (Cook Medical). • 6F Sofia Plus reperfusion catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 20 mm Solitaire Platinum stent retriever (Medtronic). • 3 x 20 mm Trevo stent retriever (Stryker). • 8F AngioSeal percutaneous closure device.

This is a very unusual case of bilateral acute ACA occlusion. Initial bilateral symptoms could mislead the clinician. CTA and CTP are consistent with bilateral ACA occlusion or perhaps occlusion of unilateral azygous ACA. The thrombus was approached through the left ACA and we could observe a left ACA stump. An initial pass was performed with a 4 x 20 mm size device achieving partial revascularization; a second pass with a smaller device (3 x 20 mm) finished the revascularization. During both passes, the reperfusion catheter (6F Sofia Plus) was advanced as far as possible to the proximity of the thrombus. If complete revascularization was not achieved, we might have used a smaller reperfusion catheter (5F Sofia [Microvention] or 4MAX [Penumbra]) to reach further distally.

Tips, Tricks & Complication Avoidance • Acute occlusion of bilateral and azygous ACA is extremely rare and only one case has been reported in the literature. Endovascular management is similar to middle cerebral or internal carotid artery

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occlusion. The left azygous ACA is large enough to accommodate a 6F large bore aspiration catheter and a 4 x 40 mm stent retriever. • When encountering ACA occlusion, it is important to assess the contralateral circulation and anterior communicating artery.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Case Overview

CASE 18.10 Acute Middle Cerebral Artery Occlusion: Solitaire Platinum

• A 70-year-old female presented to the emergency room after feeling dizzy and falling. Subsequently, she developed left facial droop, leftsided weakness, and difficulty speaking. She was seen normal 3 h prior to her arrival. On neurological examination, she was awake, confused, with slurred speech, and left hemiparesis. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 25.

She has a past medical history of hypertension and hyperlipidemia. Patient received tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. CT angiography demonstrated right middle cerebral artery (MCA) occlusion. CT perfusion showed increased time-to-peak with preserved volume on right MCA territory.

Fig 18.10a  CT angiography showing complete right MCA.

Fig 18.10b  CT perfusion with increased time-to-peak and preserved volume on right MCA territory.

Fig 18.10c  Artist’s illustration of endovascular mechanical thrombectomy right MCA occlusion with Solumbra technique using Solitaire Platinum device.

Fig 18.10d  Angiography showing right MCA occlusion.

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Fig 18.10e  Accessing distal MCA with microcatheter.

Fig 18.10f  Stent retriever (6 x 40 mm Solitaire Platinum).

Fig 18.10g  Removing aspiration catheter and stent retriever under aspiration.

Fig 18.10h  Complete revascularization of right MCA after mechanical thrombectomy.

Video 18.10  Solitaire platinum SOLUMBRA mechanical thrombectomy for acute MCA occlusion

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18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 9F sheath. • 0.035-inch Glidewire. • 8F FlowGate balloon guide catheter (Stryker). • 68 ACE aspiration catheter (Penumbra). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • 6 x 30 mm Solitaire Platinum stent retriever (Medtronic). • 8F AngioSeal percutaneous closure device.

This patient has acute right MCA occlusion. The approach was similar to other mechanical thrombectomy cases; a balloon guide catheter was used to remove the thrombus under flow arrest and prevent fragmentation. In this particular case, the stent retriever Solitaire Platinum was used. This particular device has markers every 5, 6, or 10 mm, allowing for better tracking and visualization during advancing and deployment.

Tips, Tricks & Complication Avoidance • Solitaire Platinum sizes include 4 x 20 mm, 4 x 40 mm, 6 x 20 mm, 6 x 24 mm, and 6 x 20 mm. The 4 mm and the 6 mm devices require a 0.021-inch and a 0.027-inch microcatheter. Number of markers varies from 3 to 5. • The 6 x 40 mm device could cover large thrombus lengths from distal MCA (M1) down to ICA terminus.

• The MindFrame Capture LP device is one of the few mechanical thrombectomy devices compatible with a 0.017-inch microcatheter class. It is designed to navigate, access, and treat distal zone occlusions. It has distal and proximal markers for accurate positioning and a proprietary cell geometry minimizing deformation. Sizes of the device are 3 x 15 mm, 3 x 23 mm, 4 x 15 mm, and 4 x 23 mm.

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Case Overview

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CASE 18.11 Acute Middle Cerebral (M2) Occlusion: Trevo Stent Retriever

• A 86-year-old male presented to the emergency department after he was found down with left-sided weakness. He was seen normal 1 hour prior to his arrival. On neurological examination he was awake, confused, with slurred speech, left hemiparesis, and left facial palsy. His initial National Institutes of Health Stroke Scale score (NIHSS) was 15. He has past medical history of hypertension and atrial fibrillation.

Patient received tissue plasminogen activator (tPA) with moderate improvement. • Computed tomography (CT) was normal. CT angiography demonstrated right middle cerebral artery (MCA) occlusion. CT perfusion showed increased time-to-peak with preserved volume on right MCA territory.

Fig 18.11a  CT angiography showing complete right MCA occlusion.

Fig 18.11b  CT perfusion with increased time-to-peak and preserved volume on right MCA territory.

Fig 18.11c  Artist’s illustration of endovascular mechanical thrombectomy right MCA occlusion with Solumbra technique using a Trevo stent-retriever device.

Fig 18.11d  Anteroposterior angiogram showing right MCA (2) occlusion.

18  Anterior Circulation Mechanical Thrombectomy with a Stent Retriever

Fig 18.11e  Accessing distal MCA with microcatheter (red arrow).

Fig 18.11f  Stent retriever (3 x 30 mm Trevo) deployment.

Fig 18.11g  Complete revascularization of right MCA (M2) after mechanical thrombectomy.

Video 18.11  Balloon guide catheter and SOLUMBRA mechanical thrombectomy for acute MCA (M2) occlusion

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Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 9F sheath. • 0.035-inch Glidewire • 9F concentric balloon guide. catheter (Concentric Medical). • 5 ACE aspiration catheter (Penumbra). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 3 x 20 mm Trevo stent retriever (Stryker). • 8F AngioSeal percutaneous closure device.

The current patient initially presented with acute MCA (M1) occlusion and received tPA. By the time he arrived at the interventional radiology suite, his neurological condition had improved. We still proceed with diagnostic angiography that at first seems to be normal; however, as a distal M2 occlusion is still present, we continued with the intervention. A small (3 x 20 mm) stent retriever and a medium-sized aspiration catheter were used.

Tips, Tricks & Complication Avoidance • It is not uncommon to observe partial thrombus lysis after tPA administration with clinical and radiographic improvement several minutes after. It is important to continue with a diagnostic cerebral angiography to assess for residual or distal occlusions. Clinical improvement after tPA does not necessarily mean that a mechanical thrombectomy procedure is not needed any longer.

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• Recent systematic review on mechanical thrombectomy for MCA M2 segment occlusion demonstrated that it affords functional independence to most patients, with a modest rate of symptomatic intracerebral hemorrhage. M2 occlusions should be given the same consideration as M1 occlusions.

19  Posterior Circulation Mechanical Thrombectomy Jason M. Davies, Elad I. Levy, and Adnan H. Siddiqui

General Description Although strokes to the posterior circulation territory are less frequent than those to the anterior circulation, they represent an important opportunity for intervention that can be complex because of anatomical limitations as well as a lack of devices designed specifically with these limitations in mind. Often treatment of these lesions requires flexibility and creativity to achieve adequate revascularization.

Indications Despite that posterior circulation strokes have limited clinical trials data, compared to those of the anterior circulation, many feel that thrombectomy, in particular, for basilar occlusion, is strongly indicated because of the catastrophic consequences of untreated basilar artery strokes. We routinely treat posterior circulation strokes with mechanical thrombectomy in patients who present with clinical and imaging evidence of large vessel occlusion (vertebral, basilar, CSAs, or PCAs), a National Institutes of Health Stroke Scale (NIHSS) > 5, and lack clear evidence of brainstem infarction.

Neuroendovascular Anatomy and Imaging Evaluation The paired vertebral arteries arise from the bilateral subclavian arteries. Obtaining adequate computed tomography angiogram imaging from the arch to the vertex is important in patients with potential for posterior circulation strokes for two reasons. First, one of the most common sources of emboli to the posterior circulation is vertebral origin stenosis, so it is useful to understand whether stenting or angioplasty might be needed en route to thrombectomy. Second, anatomy is variable in several domains, including dominance of the vertebral arteries and the location and angularity of the vertebral artery origin, all of which should be considered when evaluating whether to proceed with a transfemoral or transradial approach for access to the target vessel. The vertebral arteries join after entering the intracranial space to form the basilar artery that runs anterior to the brainstem. The basilar artery gives rise to several arteries, but for the purposes of thrombectomy, the important arteries to evaluate are the superior cerebellar arteries (SCAs) and posterior cerebral arteries (PCAs). Importantly, one must evaluate patency and relative contributions through the posterior communicating arteries to understand which vessels one expects to be patent, atretic, or occluded by thrombus. One final anatomical consideration is that in many patients, the vertebral artery is not large enough to safely accommodate a triaxial system, so measuring vessels and planning the treatment approach accordingly is vital.

Specific Technique and Key Steps 1. Review the noninvasive imaging studies to identify the best access route and laterality of approach. 2. Usually, a biaxial system is all that can be accommodated by the vertebral arteries. In this case, the femoral or radial artery access is obtained that allows the most direct access to the vertebral artery of interest. 3. A Benchmark (Penumbra) or similar 6 French (F) distal access catheter is advanced over a Berenstein (Cook Medical) or Simmons select (Cordis) catheter and 0.035-inch angled Glidewire (Terumo) to access the origin of the vertebral artery (Fig. 19.1-19.3, Video 19.1-19.3).

4. Distal wire access is obtained, often extending to the level of the C1 vertebra; and the guide catheter is advanced as far as can easily be performed, after which the wire is withdrawn. 5. The microsystem, consisting of the microcatheter (either for stent delivery or distal aspiration) and 0.014-inch J-shaped microwire, is advanced into the basilar artery (Video 19.1-19.3). 6. If possible, the guide catheter may be advanced over the microsystem to improve distal support and provide the possibility of aspiration through the guide catheter. 7. The microwire is advanced to the clot face (for a direct aspiration first pass technique, ADAPT) or crosses the clot in a J fashion (for use of a stent retriever) and the microcatheter is advanced into position (Video 19.1-19.3). 8. For a stent retriever procedure, the wire is withdrawn and 3 cc of 100% contrast material is used to obtain an angiographic run documenting that the clot is completely crossed, and that the catheter is within the vessel lumen (Fig. 19.1-19.3, Video 19.119.3). The stentriever is then deployed using standard techniques (see Chapter 17). 9. For aspiration alone, the microcatheter is advanced to the clot face, engaged in the clot, and withdrawn using standard techniques (see Chapter 16). 10. Standard thrombectomy techniques apply (see Chapters 16 and 17), with the main difference being that intermediate catheters are rarely used, so it is crucial to ensure back bleeding from the guide catheter after removal of the retrieval device because, in this case, the likelihood of clot fragments lodging in the guide is higher (Fig. 19.1-19.3, Video 19.1-19.3). 11. Follow-up runs are obtained through the guide catheter. 12. Once adequate revascularization has been obtained, the guide is withdrawn into the cervical vertebral artery and completion runs are obtained. 13. The guide is withdrawn, and the access point is closed.

Device Selection • 6F short femoral or radial sheath. • Benchmark or similar 6F distal access system with Berenstein select catheter. • 0.035-inch angled Glidewire. • 3MAX (Penumbra) or similar aspiration catheter. • Velocity (Penumbra) or similar microcatheter for stent retriever. • 0.014-inch microwire (Synchro 2, Stryker).

Pearls • For difficult clots within large vertebral arteries, the use of triaxial systems may be an option. In such cases, the guide catheter is placed within the distal cervical vertebral artery and the aspiration microcatheter is advanced from that position, as is typically done for anterior circulation stroke interventions. • Radial access with triaxial systems is most safely achieved using sheathless guide catheter placement (Fig. 19.3, Video 19.3). The 6F sheath is placed, after which an exchange length wire is advanced into the arch; the sheath is exchanged out; and a guide catheter, such as the Neuron MAX (Penumbra) or Infinity (Medtronic), without a sheath, is advanced with the introducer into the arch. • Aspirating from the guide catheter helps to reduce the risk of distal emboli, even if the guide catheter cannot be engaged directly in the clot face.

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Case Overview

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CASE 19.1 Acute Basilar Artery Occlusion: Solumbra Technique

• A 82-year-old female was brought to the emergency department after sudden lost of consciousness. On arrival, she was unresponsive, eyes closed, pupils 3 mm symmetric but sluggishly reactive to light, with sixth cranial nerve palsy and localizing to pain stimulation bilaterally. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 21. She has a past medical history of hypertension, diabetes, and atrial

fibrillation. She recently stopped coumadin because of hip fracture that required surgery. Patient received tissue plasminogen activator (tPA) with no improvement. • Computed tomography (CT) was normal. CT angiography demonstrated basilar artery (BA) occlusion. CT perfusion showed increased time-topeak with preserved volume on posterior circulation territory.

Fig 19.1a  CT angiography showing complete basilar artery occlusion.

Fig 19.1b  CT perfusion with increased time-to-peak and preserved volume on posterior circulation.

Fig 19.1c  Artist’s illustration of endovascular mechanical thrombectomy basilar artery occlusion with Solumbra technique.

Fig 19.1d  Anteroposterior angiogram showing subclavian and vertebral artery access.

19  Posterior Circulation Mechanical Thrombectomy

Fig 19.1e  Anteroposterior angiogram showing basilar artery occlusion.

Fig 19.1f  Accessing distal posterior cerebral artery with microcatheter.

Fig 19.1g  Stent retriever (red arrow) deployment and aspiration catheter (white arrow).

Fig 19.1h  Complete revascularization of basilar artery after mechanical thrombectomy.

Fig 19.1i  Magnetic resonance imaging at 48 h after mechanical thrombectomy. NIHSS at discharge 2.

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IV  Acute Stroke Procedures Video 19.1  Mechanical thrombectomy for acute basilar artery occlusion

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 8F sheath. • 0.035-inch Glidewire. • 6F Cook Shuttle guide catheter (Cook Medical). • 6F Sofia Plus aspiration catheter (Penumbra). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 20 mm Trevo stent retriever (Stryker). • 4 x 20 mm Solitaire stent retriever (Medtronic). • 8F AngioSeal percutaneous closure device.

Before performing posterior circulation mechanical thrombectomy, assess subclavian and vertebral arteries anatomy and evaluate the feasibility of femoral versus radial artery approach to the vertebral artery (VA). In the current case, the anatomy was favorable for a left VA approach. A 6F Cook guide catheter was advanced into the V1 segment of the left VA. The triaxial system (aspiration catheter, microcatheter, and microwire) was then advanced up to the BA. Navigate the microwire carefully avoiding perforators arising from the dorsal aspect of the BA. The stent retriever should be deployed from a posterior cerebral artery down to the BA, covering the entire thrombus length. The current case required several passes to achieve adequate revascularization of the BA. Before removing the stent retriever, bring the reperfusion catheter as close as possible to the thrombus to facilitate thrombectomy.

Tips, Tricks & Complication Avoidance • In contrast to anterior circulation stroke, there is no evidence from randomized trials that mechanical thrombectomy with modern stent retrievers or thromboaspiration is safe and effective in posterior circulation stroke. Several registries suggest that mechanical thrombectomy in posterior circulation strokes has a lower risk of

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symptomatic intracranial hemorrhage and similar effectiveness compared to anterior circulation. Patients also seem to benefit from mechanical thrombectomy started beyond 6 hours after symptom onset.

19  Posterior Circulation Mechanical Thrombectomy

Case Overview

CASE 19.2 Acute Basilar Artery Occlusion Secondary to Progressive Intracranial Atherosclerosis: Submaximal Angioplasty

• A 59-year-old female was brought to the emergency department with headaches, nausea/vomiting, difficulty speaking, and right-sided weakness. On examination, the patient was lethargic, confused, pupils 3 mm symmetric but sluggishly reactive, and right-sided hemiparesis. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 17. She rapidly deteriorated and had to be intubated. She has a past medical history of hypertension, hyperlipidemia, and intracranial atherosclerosis disease treated medically with dual antiplatelet

therapy. She received tissue plasminogen activator (tPA) with no improvement. • Computed tomography (CT) was normal. CT angiography demonstrated basilar artery (BA) occlusion. CT perfusion showed increased time-topeak with preserved volume on posterior circulation territory. • Patient had a diagnostic cerebral angiography two years prior to her actual presentation that showed moderate to severe BA stenosis that was treated medically.

Fig 19.2a  Basilar artery stenosis diagnosed 2 years prior to patient’s current presentation.

Fig 19.2b  Current CT angiography demonstrating complete basilar artery occlusion.

Fig 19.2c  CT perfusion with increased time-to-peak and preserved volume on posterior circulation.

Fig 19.2d  Artist’s illustration of endovascular submaximal angioplasty of basilar artery occlusion.

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Fig 19.2e  Access into the left vertebral artery.

Fig 19.2f  Complete basilar artery occlusion (TICI 0).

Fig 19.2g  Crossing stenosis and obtaining distal access.

Fig 19.2h  Anteroposterior view of the Initial balloon angioplasty.

Fig 19.2i  Lateral view of progressive balloon angioplasty.

Fig 19.2j  Complete revascularization of basilar artery after submaximal angioplasty.

19  Posterior Circulation Mechanical Thrombectomy

Fig 19.2k  Magnetic resonance imaging at 48 h after mechanical thrombectomy. NIHSS at discharge 2.

Video 19.2  Submaximal angioplasty for acute basilar artery occlusion

Procedure • The patient underwent emergent cerebral angiography and endovascular attempted mechanical thrombectomy and submaximal angioplasty. The procedure was performed under general anesthesia through a right femoral artery approach. 3,000 units of heparin were administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 8F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 6F Sofia Plus aspiration catheter (Microvention). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 2 x 12 mm Sprinter Legend RX semicompliant angioplasty balloon (Medtronic). • 8F AngioSeal percutaneous closure device.

Intracranial atherosclerosis (ICAD) could progress to acute artery occlusion as demonstrated in the current case. After obtaining left vertebral artery access, an initial mechanical thrombectomy was done with aspiration catheter alone, obtaining minimal revascularization. Knowing that this patient had existing severe BA ICAD, we proceeded with submaximal angioplasty instead of a second mechanical thrombectomy attempt. The balloon was sized around 70% of the BA diameter. After submaximal angioplasty, adequate flow was obtained and the procedure was terminated. Patient needs adequate follow-up as she might still need a second submaximal angioplasty or stenting.

Tips, Tricks & Complication Avoidance • Basilar artery occlusion is a life-threatening situation and noncompatible with life. Prompt recognition is imperative; however, at times, it is not recognized because of the wide variety of presenting symptoms (altered mental status, multiple cranial nerve involvement, bilateral symptoms, seizures).

• Symptomatic moderate-to-severe ICAD, especially posterior circulation, requires strict follow-up and aggressive medical management as well as early intervention (submaximal angioplasty, stenting, bypass) as it could progress to complete occlusion, as shown in this case.

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Case Overview

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CASE 19.3 Acute Posterior Cerebral Artery Occlusion in a Young Patient

• A 35-year-old female was brought to the emergency department with sudden onset of slurred speech and difficulty moving her right arm and leg. On examination, the patient was awake, confused, dysarthric, with reactive asymmetric pupils and right-sided hemiparesis. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 10.

She has no past medical history of importance. She received tissue plasminogen activator (tPA) with minimal improvement. • Computed tomography (CT) was normal. CT angiography demonstrated left posterior cerebral artery (PCA) occlusion. CT perfusion showed increased time-to-peak with preserved volume on left PCA territory.

Fig 19.3a  CT angiogram showing left PCA occlusion.

Fig 19.3b  3D CT angiography demonstrating PCA occlusion.

Fig 19.3c  CT perfusion with increased time-to-peak and preserved volume on left PCA territory.

Fig 19.3d  Artist’s illustration of endovascular mechanical thrombectomy of PCA occlusion.

19 Posterior Circulation Mechanical Thrombectomy

Fig 19.3e Access into the right vertebral artery.

Fig 19.3f Left PCA occlusion.

Fig 19.3g Distal PCA access.

Fig 19.3h Stent retriever deployed.

Fig 19.3i Complete revascularization of left PCA and basilar artery.

Fig 19.3j Magnetic resonance imaging at 48 h after mechanical thrombectomy. NIHSS at discharge 0.

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IV  Acute Stroke Procedures Video 19.3  Mechanical thrombectomy for acute posterior cerebral artery occlusion

Procedure • The patient underwent emergent cerebral angiography and endovascular mechanical thrombectomy. The procedure was performed under general anesthesia through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.027-inch velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 40 mm Solitaire stent retriever (Medtronic). • 6F AngioSeal percutaneous closure device.

Young patients have relatively straightforward vessels and access into the posterior circulation is relatively simple. In this young patient, a 6F femoral sheath and a Benchmark guide catheter were sufficient to establish adequate vertebral artery (VA) access. The guide catheter was advanced up to the V3 segment of the VA. Under road map, the triaxial system (reperfusion catheter, microcatheter, and microwire) was advanced at the basilar artery. The microcatheter was advanced further out at the P3 segment of the left PCA. The stent retriever device was deployed mostly at the PCA to cover all thrombus. Before pulling the device, the aspiration catheter was advanced at the distal segment of the BA. The single stent retriever pass was sufficient to achieve complete revascularization.

Tips, Tricks & Complication Avoidance • Permanent occlusion of the proximal PCA could cause significant neurological deficits, including thalamic and midbrain strokes. • A recent multicenter study (J Neurosurg. 2018;12:1–10.) included 100 patients with posterior circulation large vessel occlusion; authors concluded that successful reperfusion was a strong predictor of a 90-day favorable outcome and the choice of ADAPT as the first-line

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strategy achieves a significantly higher rate of complete reperfusion with a shorter procedure duration. • Occlusion of the proximal (P1-P2) PCA should be considered large vessel occlusion and treated with mechanical thrombectomy if indicated.

20  Mechanical Thrombectomy with Intracranial Stenting/ Angioplasty Kunal Vakharia, Muhammad Waqas, Adnan H. Siddiqui, and Elad I. Levy

General Description Atherosclerotic stenosis may be the underlying cause for an acute ischemic stroke. Approximately 8%–10% of ischemic strokes in the United States are attributed to intracranial atherosclerotic disease (ICAD). This accounts for nearly 80,000 new strokes per year. The pathophysiology behind these plaques is similar to plaques in the extracranial vasculature as well. Thrombosis at the site of stenosis secondary to plaque rupture or hemorrhage or progressive occlusive plaque growth can lead to acute ischemic large-vessel occlusions. ICAD tends to affect the middle cerebral artery (MCA) and internal cerebral artery (ICA), although nearly 40% of ICAD-related strokes are in the posterior circulation. Although medical management with antiplatelet therapy was shown to be a good first-line therapy, in the setting of acute large-vessel occlusion, intervention is prudent and management of the underlying stenosis may be warranted.

Evidence for Mechanical Thrombectomy with Intracranial Stenting/Angioplasty • The Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) demonstrated an absolute difference of 13.5 percentage points (95% CI, 5.9 to 21.2) in the rate of functional independence (modified Rankin Scale [mRS] score, 0 to 2) at 90 days in favor of the intervention (32.6% vs. 19.1%). • Endovascular treatment for small core and anterior circulation proximal occlusion with emphasis on minimizing CT to recanalization times (ESCAPE) demonstrated that endovascular intervention had favorable 90-day outcomes (mRS score, 0–2) in 53% of patients, which was statistically better than the control group with only 29% favorable outcomes. • Solitaire with the intention for thrombectomy as primary endovascular treatment (SWIFT PRIME) was a 39-center international randomized trial demonstrating a significant benefit for endovascular therapy in 90-day favorable outcome (mRS score, 0–2) with a p < 0.001. • Stenting of symptomatic atherosclerotic lesions in the vertebral or intracranial arteries (SSYLVIA) demonstrated a 30-day stroke rate of 7.2% and delayed stroke rate of 10.9%, improving on outcomes from stenting and aggressive medical management for preventing recurrent stroke in intracranial stenosis (SAMMPRIS). • In 2017, Yi et al.1 evaluated 12 consecutive patients with large-vessel occlusions requiring balloon-assisted or stent-assisted angioplasty for ICAD demonstrating successful recanalization with an mRS score of 6. Intervention should be carried out within 6 hours of symptoms or if the patient has perfusion imaging revealing a large penumbra with little or no ischemic core. Computed tomographic (CT) angiography of the head and neck vessels is necessary to make a diagnosis of tandem occlusion and plan treatment adequately. We prefer stenting to angioplasty alone to prevent restenosis and continued embolization; however, an antiplatelet regimen must be prescribed in conjunction with stenting procedures.

Neuroendovascular Anatomy The ICA normally originates from the CCA at the C3-4 or C4-5 vertebral level; it may occur as low as T2 and as high as C1. The petrous portion of the ICA runs forward and medial to the area of the foramen lacerum where it moves superiorly into the cavernous sinus and creates a siphon upon itself before exiting at the distal dural ring. The ICA bifurcates into the first anterior cerebral artery segment (A1) and the first segment of the MCA (M1). The M1 segment (4–5 mm diameter) can have accessory and duplicated branches. Perforators going to the basal ganglia (i.e., lenticulostriate arteries) arise from the superior surface of the M1, and care should be taken to avoid inadvertent selection of these with a microwire. The MCA bifurcates (trifurcates on occasion) again near the bottom of the sylvian fissure, and an inferior branch proceeds to the M3 and M4 segments over the temporoparietal region. The superior M2 division moves frontally, supplying the M3 and M4 vessels to Broca’s area as well as the motor area. Vessels in patients with AIS can have severe intracranial atherosclerotic disease (ICAD). Thrombi can form at these disease sites as well. Furthermore, some patients can

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become symptomatic from ICAD stenosis caused by hypoperfusion; and the symptoms can mirror AIS; however, typically, in this situation, thrombectomy is not needed. Surgical or endovascular revascularization with angioplasty or bypass is necessary in those types of cases.

Periprocedural Medications Anterograde stenting with thrombectomy and intracranial thrombectomy followed by retrograde stenting procedures are usually performed with the patient awake and under little or no sedation. Typically, the patient has received tPA, and further anticoagulation or antiplatelets are contraindicated. A loading dose of aspirin (650 mg) and clopidogrel (600 mg) or ticagrelor (180 mg) is administered preprocedurally.

Specific Technique and Key Steps 1. All necessary catheters are assembled on a table at the back of the angiography suite and connected to heparinized flushes. They are laid out on the angiogram table coaxially. 2. Access is obtained via a femoral arteriotomy performed, if possible, with the use of a micropuncture set. A 6 or an 8 French (F) sheath is inserted. Under fluoroscopy, the microwire should be deemed appropriate in relation to the femoral head before dilating up to a larger size sheath. If an 8F sheath is placed, a transitional 6F dilator is utilized. A 9F sheath is necessary when a balloon-guide catheter is used (e.g., 9F MoMa dual balloon-guide catheter, Medtronic). 3. The guide sheath (90 cm length) with Copilot Valve is placed over an intermediate catheter (e.g., VTK 125-cm diagnostic catheter, Cook Medical) and over a glidewire (e.g., Glidewire Advantage 180 cm, Terumo) and advanced into the CCA. 4. Digital subtraction angiography (DSA) runs are taken from the CCA prior to advancing the guide catheter into the ICA under roadmap guidance (Fig. 21.1, 21.2, Video 21.1, 21.2). 5. The extracranial occlusion is identified, and working roadmap views are obtained. 6. If the extracranial vessel is occluded and distal flow is absent, gentle suction through the guide or intermediate catheter can be utilized prior to crossing the occlusion with the microcatheter (Video 21.1, 21.2). 7. If the microcatheter cannot be advanced across the stenotic/ occlusive extracranial lesion, balloon angioplasty may be necessary. This can be performed under flow arrest with a balloonguide catheter. Once the microcatheter is beyond the lesion, microinjection can be performed to ensure that the length of the lesion is covered by the stent (Video 21.1, 21.2). 8. A stent is then navigated through the stenosis/occlusion and deployed under fluoroscopy. A post-balloon angioplasty is utilized if stenosis remains after stent placement (Fig 21.1, 21.2, Video 21.1, 21.2). 9. Intracranial anteroposterior and lateral DSA runs are performed, and the intracranial occlusion site is identified. 10. An assembled triaxial system that includes an intermediate largebore aspiration catheter (e.g., Sofia or Sofia Plus, MicroVention; 5 MAX or 64 aspiration catheter, Penumbra), a 0.0027-inch microcatheter (Headway, MicroVention; Velocity, Penumbra; Marksman, Medtronic), and a 0.0014-inch microwire is then inserted into the guide catheter. Under fluoroscopy, the microwire

21  Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty

11.

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16.

17.

18.

and microcatheter followed by the intermediate catheter are advanced to, but not beyond, the site of the intracranial occlusion with care taken to account for any built-up tension in the system while nearing the thrombus. A direct aspiration first pass technique (ADAPT) or stent-retriever technique can be utilized at this point (Video 21.1, 21.2). When using stent retrievers, some interventionists cross the lesion with a microwire under suction from the intermediate catheter. In any case, the lesion must be crossed with the microwire and microcatheter if a stent retriever is used. The microwire can then be withdrawn and a microinjection performed to ensure that the vasculature distal to the occlusion is patent. The stent retriever is then appropriately sized for the vessel. A 4-mm device is usually sufficient for M1 and beyond. Longer devices can be selected for longer clots. The device is pushed into the rotating hemostatic valve and back flushed. Next, the device is loaded into the microcatheter. Fluoroscopy should be utilized to push the device beyond the fluoro save marker. The catheter is pinned, and the device is pushed to the end of the catheter and beyond the clot. The ideal landing zone for the retriever is to have the clot at the mid to proximal area of the retriever (Fig 21.1, 21.2, Video 21.1, 21.2). After 3 minutes of deployment, some interventionists obtain microinjections to assess for recanalization. The microcatheter is removed, pinning the stent. The intermediate large-bore aspiration catheter is turned to suction after 3–5 minutes, and the stent retriever is slowly withdrawn into the intermediate catheter. In those cases in which a carotid stent has been placed to treat the extracranial lesion, stent-retriever removal must be accomplished under fluoroscopy. The stent retriever is observed to make sure that it is not caught with the cervical stent. This event is unlikely, but it can occur. The stent retriever is inspected for clot. Final runs are obtained to determine whether contrast extravasation is present and another pass is needed. The intermediate catheter is also withdrawn under suction and inspected for clot. The guide catheter should be aspirated with two large (30 mL) syringes. Post-thrombectomy DSA runs are performed. If the clot is removed and a thrombolysis in cerebral infarction grade of 2b or 3 is achieved, the procedure is done, and the patient’s neurologic status should be checked. If the clot persists, consideration is given to whether another pass is needed (Video 21.1, 21.2). After removing the guide catheter, CCA runs are performed as well as a groin run (if not already performed) to determine eligibility for a closure device (e.g., AngioSeal, Terumo). If the patient is stable and more information about collateral supply is needed, a full diagnostic angiogram can be completed.

Device Selection In our practice, the following are the common setups and devices used for anterior circulation mechanical thrombectomy with extracranial stenting/angioplasty. • 21-gauge micropuncture set, Cope Mandril wire (Cook Medical), 6F dilator, 6F or 8F sheath. • Guide catheter or balloon guiding catheter (e.g., 90-cm Neuron MAX guide catheter, Penumbra; 6F Flexor Shuttle, Cook Medical; 9F MoMa dual balloon guide catheter, Medtronic). • Intermediate catheter (e.g., VTK 125-cm 5F catheter).

• 0.035-inch wire (e.g., 180-cm Glidewire Advantage). • Large-bore aspiration catheter (e.g., Sofia or Sofia Plus; 5 MAX or 64 aspiration catheter). • 0.0027-inch microcatheter (e.g., Headway; Marksman; Velocity). • 0.0014-inch wire (e.g., Synchro 2 standard or soft wire, Stryker). • Suction tubing or a large aspiration syringe. • Continuous heparinized saline. • Stent retriever (e.g., Trevo, Stryker or Solitaire, Medtronic). • Balloon angioplasty catheter (e.g., Viatrac Peripheral Dilatation Catheter, Abbott Vascular). • Closed-cell carotid artery stent (e.g., Wallstent, Boston Scientific).

Pearls • If tandem occlusions are identified and carotid stenting is needed, we prefer to stent the carotid artery and then treat the intracranial thrombus (i.e., proximal to the distal reconstruction) (Video 21.1, 21.2). The guide can be advanced past the stent, if possible, before stent retriever thrombectomy to avoid disturbing the new carotid stent. Alternatively, ADAPT can be utilized. • Tapered stents are utilized when needed to match vessels; good approximation is the key to preventing further emboli. • We prefer small closed-cell stents to tack down unstable plaque in acute stroke. • If microinjections demonstrate long segment stenosis or dissection, tandem stenting can be utilized. • Delivering the guide catheter into the CCA in tortuous anatomy can be difficult. After a CCA run, the 0.035-inch or 0.038-inch wire can be looped into the external carotid artery for extra purchase. • When navigating past a thrombus, use caution and knowledge of anatomy to ensure that you stay within a vessel even though it may not fill on subtracted images. This will help avoid perforations. • A gentle “J” curve is needed on the microwire to allow navigation of the cerebral vessels and avoid perforation. • Beware of dissections that can masquerade as thrombus. Microinjections can help to discern the thrombus from dissections. The skull base and distal dual ring are common locations for dissections. • Always beware of reperfusion hemorrhage. Monitor DSA runs for contrast extravasation and stagnation. • Balloon-guide catheters can be used (e.g., Cello, Medtronic); however, they can be very stiff and require a larger sheath (9F). Some large-bore aspiration catheters will not fit within the balloon-guide catheter. • Distal clot migration is possible with ADAPT as well as stent retrieval. If concern exists, a run is performed. If a smaller vessel is blocked distally, smaller aspiration catheters can be utilized (e.g., 3 MAX or 5 MAX catheters, Penumbra). • Beyond the M2 vessels, the risk versus benefit ratio starts to become unfavorable for intervention. If the initial NIHSS score was >6 and no LVO was found on angiography, it is likely that the tPA broke up the clot. • Reperfusion hemorrhage and perforation are the two main concerns associated with anterior circulation mechanical thrombectomy with extracranial stenting/angioplasty. A balloon-guide catheter can be inflated temporarily to treat reperfusion hemorrhage. If perforation is encountered on microinjection prior to clot removal, the stent retriever device is resheathed and the thrombus is allowed to palliate the hemorrhage. • CT should always be obtained routinely to exclude ICH because the patient has received dual antiplatelet agents and possibly tPA.

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Case Overview

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CASE 21.1 Emergent Carotid Artery Stenting and Mechanical Thrombectomy for Acute Tandem Occlusion

• A 56-year-old male was admitted to the emergency department with acute onset of right-sided weakness, and difficulty talking with hemiparesis. Symptoms started 2 hours prior to his arrival. Neurological examination showed the patient was awake but confused, with right facial palsy, left gaze deviation, right hemiparesis, and dysarthria. His initial National Institutes of Health Stroke Scale

score (NIHSS) was 14 points. Patient has a past medical history of hypertension, hypercholesterolemia, and bipolar disorder. • Computed tomography (CT) was normal. CT angiography showed complete occlusion of the left internal carotid artery (ICA) and middle cerebral artery (MCA). CT perfusion demonstrated increased time-topeak with preserved volume on left hemisphere.

Fig 21.1a  Neck CT angiography showing complete left ICA occlusion.

Fig 21.1b  Head CT angiography showing complete left ICA and MCA occlusion.

Fig 21.1c  CT perfusion showing increased time-to-peak with preserved volume on left hemisphere.

Fig 21.1d  Artist’s illustration of acute tandem occlusion management with carotid stenting and mechanical thrombectomy under flow arrest with a balloon guide catheter.

21  Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty

Fig 21.1e  Left ICA occlusion.

Fig 21.1f  Balloon guide inflated creating flow arrest and lesion crossed with 0.014inch wire.

Fig 21.1g  Stent and balloon angioplasty performed under flow arrest.

Fig 21.1h  After establishing flow in the ICA, intracranial angiogram shows complete left MCA occlusion (TICI 0).

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Fig 21.1i  Final intracranial angiography demonstrating complete MCA revascularization (TICI 3).

Video 21.1  Endovascular treatment of acute tandem MCA and cervical ICA occlusion I

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21  Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty

Procedure • Patient received tissue plasminogen activator (tPA) in the emergency department. After advanced imaging was obtained, he received a bolus of aspirin (650 mg) and clopidogrel (600 mg). He was transferred directly to interventional neuroradiology where he underwent emergent carotid artery stenting angioplasty and middle cerebral mechanical thrombectomy. The procedure was performed under conscious sedation and through a right femoral artery approach. 3,000 units of heparin were administered.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 7F dilator. – 9F sheath. • Concentric balloon guide catheter (Concentric Medical). • Vitek catheter (Cook Medical). • 0.038-inch Glidewire. • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Aviator balloon 4 x 20 mm (Abbott). • 6F Sofia Plus intermediate catheter 125 cm (Microvention). • 0.027-inch Velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • Stent Retriever Trevo 4 x 30 mm (Stryker). • 8F AngioSeal percutaneous closure device.

Acute tandem occlusions of the cervical internal carotid artery and intracranial large vessel present treatment challenges. If possible, we advocate a proximal-to-distal approach. Once flow through the ICA has been established, with either balloon angioplasty and/or stenting, we proceed with the intracranial mechanical thrombectomy. In the current case, we use a balloon guide catheter to achieve flow arrest while crossing the stenosis, reducing the risk of further intracranial emboli. Intracranial mechanical thrombectomy can be performed either with direct aspiration (ADAPT) or stent retriever and aspiration (Solumbra). The patient was loaded with dual-antiplatelet boluses en route to the procedure; other alternatives include intraprocedural administration of glycoprotein IIa/IIIb bolus follow by 24 h infusion.

Tips, Tricks & Complication Avoidance • Tandem occlusions present treatment challenges, but high recanalization rates are possible using acute carotid artery stenting and mechanical thrombectomy concurrently. Proximal-to-distal and aspiration approaches are most commonly used because they were safe, efficacious, and feasible (Neurosurg Focus. 2017;42(4):E16). • It is important for the neurosurgeon or neurointerventionist to look at the CT angiography prior to the endovascular procedure. Be prepared

with adequate large guide catheter, balloon angioplasty, and carotid stents. • It could be difficult to assess the exact length of carotid artery stenosis; we recommend the use of large stents (e.g., 8 x 36 mm) to adequately cover the stenosis. Do not deploy the stent near vessel turns as this could straighten the vessel and cause kinking of the artery above or below the stent.

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Case Overview

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CASE 21.2 Tandem Occlusion (Cervical Internal Carotid and Middle Cerebral Arteries): Stent Retriever and Carotid Artery Stenting Angioplasty

• A 52-year-old female presented to the emergency department after waking up with severe right facial, upper and lower extremity weakness. At the time she was examined, all her symptoms had resolved. Her initial National Institutes of Health Stroke Scale score (NIHSS) was 12. She has a past medical history of hypertension,

coronary artery disease, previous stroke, and atrial fibrillation. She did not received tissue plasminogen activator (tPA). • Computed tomography (CT) was normal. CT angiography demonstrated left internal carotid artery (ICA) occlusion and left middle cerebral artery (MCA). CT perfusion showed mild increased time-to-peak with preserved volume on left ICA territory.

Fig 21.2a  Neck CTA showing left ICA occlusion.

Fig 21.2b  CT perfusion with increased time-to-peak on left MCA territory.

Fig 21.2c  Artist’s illustration of endovascular treatment of tandem (ICA/MCA) occlusion with carotid stenting and stent retriever mechanical thrombectomy.

Fig 21.2d  Cerebral angiography showing left ICA occlusion.

21  Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty

Fig 21.2e  Balloon guide catheter advanced into the left ICA.

Fig 21.2f  Under flow arrest (balloon guide catheter inflated), distal access is obtained to check patency of distal cervical ICA (arrows).

Fig 21.2g  Carotid stent deployment.

Fig 21.2h  ICA revascularization.

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Fig 21.2i  Left MCA occlusion.

Fig 21.2j  Distal MCA access and stent retriever (arrow) deployment.

Fig 21.2k  Removing stent retriever under aspiration.

Fig 21.2l  Complete left ICA/MCA revascularization.

Video 21.2  Endovascular treatment of acute tandem MCA and cervical ICA occlusion II

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21  Anterior Circulation Mechanical Thrombectomy with Extracranial Stenting/Angioplasty

Procedure • The patient underwent cerebral angiography and endovascular management of ICA and MCA occlusion. In the ER, the patient received a bolus of 650 mg aspirin and 600 mg clopidogrel in preparation for possible stent. The procedure was performed under conscious sedation through a femoral artery approach. 5,000 units of heparin were administered until an activated clotting time of more than 250 was reached. Patient continued taking 350 mg aspirin and 75 mg clopidogrel daily after the procedure.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 9F sheath. • 0.038-inch Glidewire. • 9F Concentric balloon catheter (Concentric Medical). • Vitek catheter (Cook Medical). • 068 MAX ACE reperfusion catheter (Penumbra). • 0.027-inch Velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • 4 x 40 mm Solitaire stent retriever (Medtronic). • 8 x 39 mm Carotid Wallstent (Boston Scientific). • 8F AngioSeal percutaneous closure device.

When treating carotid artery tandem occlusions, the initial step is to establish adequate vascular access, ideally with a large balloon guide catheter. In the current case, a 9F concentric balloon was navigated and parked at the common carotid artery and under flow arrest a microwire with a microcatheter are advanced into the ICA to assess for patency. While passing the microwire there was resistance at C3-4 level indicating the presence of severe ICA stenosis. The microcatheter was navigated through the stenosis obtaining distal access. Angiography through microcatheter confirmed distal ICA patency. The ICA stenosis was then treated with carotid artery stenting and angioplasty. Through the stent, an aspiration catheter over a microcatheter and microwire was advanced intracranially to identify intracranial vessel occlusion. We proceed with mechanical thrombectomy with Solumbra technique (stent retriever + aspiration catheter) of the MCA.

Tips, Tricks & Complication Avoidance • For tandem occlusions, there is a preference to revascularize the proximal occlusion using a stent followed by distal recanalization with mechanical thrombectomy, intra-arterial thrombolysis, or a combination of these. This approach has low periprocedural complications and can achieve an excellent angiographic and clinical outcome (J Neurointerv Surg. 2015;7(3):158–163). • Anticoagulation and antiplatelet therapy can problematic in emergent situation. If there is acute ICA occlusion and the need of carotid stenting is anticipated, there are two proposed protocols:

Load the patient with antiplatelet drug (aspirin 650 mg and clopidogrel 600 mg) prior to the intervention while the patient still in the emergency room, follow by daily standard dose the day after the procedure (Neurosurg Focus. 2017;42(4):E16). – Intraprocedural bolus of glycoprotein (GP) IIb/IIIa inhibitors (abciximab or eptifibatide) follow by 24 h infusion and dual-antiplatelet therapy the day after the procedure (Br J Neurosurg. 2017;31(5):573–579). –

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22  Intracranial Atherosclerotic Disease—Intracranial Angioplasty Kunal Vakharia, Elad I. Levy, and Adnan H. Siddiqui

General Description Intracranial angioplasty can be an effective modality of treatment for symptomatic intracranial atherosclerotic disease (ICAD). Asymptomatic patients tend to do best with aggressive medical management involving dual antiplatelet therapy with aspirin 325 mg daily and clopidogrel 75 mg daily. The Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trial demonstrated a 2-year stroke risk of 19.7% in patients taking aspirin with symptomatic ICAD and 17.2% in those taking warfarin. Since WASID, other studies have concluded that lifestyle modification and anticoagulation do not address the pathophysiology of chronic plaque buildup, but that there is support for the use of dual antiplatelet therapy. The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial demonstrated that nearly one in eight symptomatic patients had recurrent strokes within 12 months of observation after stent placement for ICAD despite aggressive medical management. The final results of the SAMMPRIS trial showed an increased rate of stroke for intervention patients versus medical management at 14.7% compared to 5.8%, respectively. In addition, the Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial Arteries (SSYLVIA) study demonstrated a lower periprocedural complication 30-day stroke rate of 7.2% and a delayed stroke rate of 10.9% using a balloon-mounted stent. Evidence subsequent to these studies has supported intracranial submaximal angioplasty for ICAD with stenting in recalcitrant cases.

Evidence for Intracranial Angioplasty • SSYLVIA demonstrated a 30-day stroke rate of 7.2% and a delayed stroke rate of 10.9% after intracranial angioplasty in symptomatic patients, improving on outcomes from SAMMPRIS. The Wingspan stent system (Stryker) study demonstrated a 30-day stroke rate of 6%. • A French study in 2011 included 63 symptomatic patients treated with submaximal angioplasty based on sizing a noncompliant balloon to match 80% of parent vessel size when inflated to nominal pressures. This study used a noncompliant Gateway Balloon Catheter (Stryker) followed by immediate Wingspan stenting. This study introduced the discussion about angioplasty alone because of the 95% success rate of improvement of flow with a 20% periprocedural complication rate and a 4.8% periprocedural permanent mortality and morbidity. • A study in 2012 that focused on submaximal angioplasty without stenting involved 41 patients demonstrating a 91% rate of no ischemic or perioperative symptoms or complications at 19 months’ follow-up. • Based on the results of a phase 1 trial, submaximal angioplasty is the ideal first surgical intervention for symptomatic intracranial stenosis that has failed aggressive medical management. The trial investigators studied 24 patients who had an average preprocedural stenosis of 80% and postprocedural stenosis of 54% with no 30-day ischemic events and a 5% rate of ischemic events at 1 year.

Indications In the WASID trial, patients with symptomatic intracranial stenosis were found to have an 11%–12% first-year risk of stroke in the same region of stenosis, with 73% of strokes happening in the region of intracranial stenosis. Similar to extracranial carotid artery stenosis, patients with lesions measuring 50%–69% stenosis had a 6% 1-year stroke risk,

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whereas patients with > 70% stenosis had a 1-year stroke risk of 19%. Indications for angioplasty centered on patients who had recurrent strokes or symptoms after aggressive medical management. A review of angiographic progression of untreated stenosis noted that 40% of lesions remain stable, 20% regress, and 40% progress, thus identifying and treating lesions that progress becomes crucial.

Neuroendovascular Anatomy ICAD primarily affects the internal carotid artery (ICA) and the middle cerebral artery (MCA) vessels. The ICA is conventionally broken into seven segments, with the last three segments being intradural. The normal luminal diameter of the ICA tends to be 3–4 mm. The MCA is conventionally divided into four segments: M1, from the origin to the bifurcation at the limen insulae; M2, the insular segment where it makes a hairpin turn and leads into the operculum; M3, opercular branches within the Sylvian fissure; and M4, branches emerging from the Sylvian fissure on the convex surface of the hemisphere. The normal luminal diameter of the M1 segment ranges from 2 to 3 mm. Lenticulostriaterich regions such as the M1 segment need to be accounted for when planning angioplasty. Posterior circulation ICAD tends to affect the intradural segment of the vertebral artery and the basilar artery. The vertebral artery diameter is roughly 3–5 mm; the basilar artery diameter is 2–3 mm. Determination of the anterior inferior cerebellar artery (AICA) origin is important when planning angioplasty for basilar artery stenosis as perforator-rich regions above the AICA origin can lead to periprocedural complications.

Periprocedural Medications Dual antiplatelet therapy with aspirin (325 mg daily) and clopidogrel (75 mg daily) is prescribed for the prevention of platelet aggregation and progression of ICAD. Although the initial results of WASID demonstrated that Warfarin had a lower 2-year stroke rate than aspirin, a randomized controlled trial evaluating 100 patients found combination therapy with aspirin and clopidogrel to be more effective. Dual antiplatelet therapy is maintained 3 months with reevaluation of the patient’s symptoms or sooner if the patient continues to be symptomatic. Aspirin and clopidogrel serum responses should be monitored and therapeutic. Patients who are found to be nonresponsive or allergic to clopidogrel can be switched to an alternative antiplatelet agent, including ticagrelor. Intraprocedural thrombus formation is always a risk and systemic heparinization is administered during the procedure because of the risk of intraprocedural thrombus formation. A weight-based intravenous bolus of heparin aimed at an activated clotting time (ACT) of 250–300 s may limit thromboembolic complications. Administration of the heparin before crossing the stenotic lesion may limit thrombus formation at the proximal end of the stenosis. For acute thrombus formation during the procedure, a glycoprotein (GP) IIb/IIIa inhibitor (e.g., eptifibatide) can be used intraprocedurally.

Specific Technique and Key Steps Submaximal angioplasty for ICAD tends to use undersized noncompliant balloons to allow for appropriate pressure and management while inflating the balloon (Fig. 22.1-22.3, Video 22.1-22.3).

22  Intracranial Atherosclerotic Disease—Intracranial Angioplasty 1. A 6 or 8 French (F) sheath is inserted in the femoral artery. 2. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a 0.035-inch curved wire into the aorta. This maneuver is completed under fluoroscopic guidance. 3. The guide catheter is brought up into the distal ICA. The guide catheter can be brought over a select catheter and 035-inch Glidewire (Terumo). 4. Cerebral angiography is performed to obtain a baseline set of images of the intracranial vasculature (Video 22.1-22.3). 5. Under roadmap guidance, a microwire backloaded into a noncompliant balloon can be used to navigate past the stenotic lesion. 6. Selection of the balloon should be sized to be 80% of normal vessel diameter when inflated to nominal pressures: a. Noncompliant balloon (Gateway, Sprinter, Medtronic; Maverick, Boston Scientific)—used for lesions measuring 1 mm in size, can be inflated to subnominal pressures of 4 atm in 2–3 mm MCA or basilar-sized vessels (2–3 mm) (Fig. 22.1-22.3, Video 22.1-22.3). b. Compliant balloons (Scepter, MicroVention)—used for lesions near branch points if concern for soft plaque is present. c. Minimally compliant coronary balloons—used in vessels of 1.25 mm–1.5 mm with the ability to measure atmospheres of pressure to correlate with balloon diameter so as to perform submaximal angioplasty similar to noncompliant balloons (Euphora). 7. The patient is systemically heparinized with an ACT in the range of 250–300 s. 8. The balloon is connected to an insufflator and inflated under fluoroscopy to a nominal pressure at the rate of 1 atm/min and subsequently deflated at a rate of 1 atm/15 s (Video 22.1-22.3). 9. Final cerebral angiographic runs are performed, and the balloon and microwire are removed.

Device Selection In the authors’ and editors’ practice, the following are common set-ups and devices used for intracranial angioplasty: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy DA XB catheter, Codman Neuro; Benchmark, Penumbra). • 0.035-inch angled Glidewire. • Intermediate 5F-diagnostic catheter (Vitek, Cook). • Synchro 2 microwire (Stryker). • Noncompliant balloon (i.e., Gateway or Sprinter balloon). • Continuous heparinized flush.

Pearls • Submaximal angioplasty with an undersized balloon minimizes vessel damage and plaque disruption, reducing the risk of thrombotic obstruction, distal emboli, and perforator infarcts. • A < 1.8F microcatheter over a 0.014-inch microwire can facilitate crossing a tight intracranial stenotic lesion. • Understanding the Mori classification of the high-risk features of a ruptured plaque is important and can help guide decision making in situations where postangioplasty intracranial stenting is required. • An intermediate catheter is sometimes needed inside the guide catheter to allow for sufficient distal access because of cervical and intracranial tortuosities. Preprocedure imaging can help guide this step in surgical planning. • Angiographic runs should be performed after each step of the procedure to ensure no extravasation is noted. • Thrombus formation proximal to the balloon needs to be carefully monitored. Early detection and administration of GP IIb/IIIa inhibitors can effectively manage this potential complication.

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Case Overview

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CASE 22.1 Severe Middle Cerebral Artery Stenosis: Submaximal Angioplasty

• A 53-year-old female presented to the emergency department with a 10-day history of intermittent word-finding difficulty and left-sided weakness. On neurological examination, she was alert, oriented, with normal motor strength except for left pronator drift. She has a past medical history of hypertension, coronary artery disease, and recurrent transient ischemic attacks. She has been taking aspirin and clopidogrel for more than 2 years.

• Computed tomography (CT) was normal. MR angiography demonstrated severe intracranial atherosclerotic disease (ICAD) and stenosis of the right internal carotid artery (ICA) and middle cerebral artery (MCA). CT perfusion showed increased time-to-peak on right ICA territory.

Fig 22.1a  Head magnetic resonance angiography showing right MCA severe stenosis.

Fig 22.1b  CT perfusion with increased time-to-peak on left MCA territory.

Fig 22.1c  Artist’s illustration of endovascular treatment of severe MCA stenosis with submaximal angioplasty.

Fig 22.1d  Cerebral angiography showing right MCA stenosis.

22  Intracranial Atherosclerotic Disease—Intracranial Angioplasty

Fig 22.1e  Pressure measurement wire.

Fig 22.1f  Submaximal angioplasty—initial balloon inflation.

Fig 22.1g  Submaximal angioplasty— progressive balloon inflation.

Fig 22.1h  Successful MCA revascularization.

Video 22.1  Submaximal angioplasty for symptomatic intracranial stenosis I

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Procedure • The patient underwent cerebral angiography and endovascular management of severe right MCA stenosis with submaximal angioplasty. The procedure was performed under conscious sedation through a femoral artery approach. 5,000 units of heparin were administered until an activated clotting time of more than 250 was reached. Patient continued taking 350 mg aspirin and 75 mg clopidogrel daily after the procedure.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 8F sheath. • 0.038-inch Glidewire. • Neuron MAX guide catheter (Penumbra). • 0.027-inch Velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microwire (Stryker). • 1.5 x 9 mm Gateway balloon angioplasty (Stryker). • 0.014-inch Volcano pressure guide wire. • 8F AngioSeal percutaneous closure device.

Patient with recurrent symptoms (TIA and/or strokes) from intracranial atherosclerosis refractory to best medical therapy (dual-antiplatelet therapy) should be considered candidates for submaximal angioplasty, as seen in this patient. The procedure is performed under conscious sedation, a 6F guide catheter is navigated into the ICA; under road map and magnification, the microcatheter and microwire (Volcano pressure wire) are advanced. MCA pressure is measured distal to the stenosis. The microcatheter and wire are removed and the submaximal balloon angioplasty was done. Pressure is measured again to confirm improvement in flow through the stenosis site. The balloon is sized 70% of the normal MCA diameter. In the current case, the normal MCA diameter was 2.5 mm; therefore, a 1.5 balloon angioplasty was used.

Tips, Tricks & Complication Avoidance • Intracranial atherosclerotic disease accounts for approximately 10% of ischemic strokes. The recent Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study demonstrated a high incidence of perioperative complications (15%) for treatment of ICAD with stenting. Angioplasty without stenting represents an alternative and understudied revascularization treatment for ICAD, limiting the risks of thromboembolism, vessel perforation, and reperfusion hemorrhage. Results of submaximal angioplasty for ICAD: a prospective phase

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I study showed the safety of the technique with no permanent periprocedural complications (J Neurosurg. 2016;125(4):964–971). • Adequate balloon sizing and precise microwire manipulation through the stenosis under magnification and road map is essential to avoid vessel perforation. • We recommend slow angioplasty balloon inflation and deflation (1 atm/30 seconds). Balloon inflation should not go beyond the nominal pressure (usually 6 atm).

22  Intracranial Atherosclerotic Disease—Intracranial Angioplasty

Case Overview

CASE 22.2 Severe Middle Cerebral Artery Stenosis: Submaximal Angioplasty and Fractional Flow Reserve

• A 66-year-old female presented to the emergency department with acute onset of transient right-sided weakness and difficulty speaking. On neurological examination, she was alert, oriented, with right facial droop, and mild right hemiparesis. She has a past medical history of hypertension, coronary artery disease, breast cancer, and recurrent transient ischemic attacks. She has been taking aspirin and clopidogrel for several years.

• Computed tomography (CT) was normal. CT angiography demonstrated severe intracranial atherosclerotic disease and stenosis of the left middle cerebral artery (MCA). CT perfusion showed increased timeto-peak on left MCA territory.

Fig 22.2a  Head CT angiography left MCA severe stenosis.

Fig 22.2b  Artist’s illustration of gradient pressure measurement before and after endovascular treatment of severe MCA stenosis with submaximal angioplasty.

Fig 22.2c  Cerebral angiography showing left severe MCA stenosis.

Fig 22.2d  Pressure measurement wire.

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Fig 22.2e  Submaximal angioplasty.

Fig 22.2f  Successful MCA revascularization.

Video 22.2  Submaximal angioplasty for symptomatic intracranial stenosis II

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22  Intracranial Atherosclerotic Disease—Intracranial Angioplasty

Procedure • The patient underwent cerebral angiography and endovascular management of severe left MCA stenosis with submaximal angioplasty and gradient pressure measurement. The procedure was performed under conscious sedation through a femoral artery approach. 5,000 units of heparin were administered until an activated clotting time of more than 250 was reached. Patient continued taking 350 mg aspirin and 75 mg clopidogrel daily after the procedure.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 8F sheath. • 0.038-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 0.027-inch Velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • 1.5 x 9 mm Gateway balloon angioplasty (Stryker). • 0.014-inch Volcano pressure guidewire. • 8F AngioSeal percutaneous closure device.

This patient with recurrent ischemic symptoms is a good candidate for submaximal angioplasty. The procedure is relatively straightforward. A guide catheter is positioned at the internal carotid artery and, under road map, the balloon angioplasty over the microwire is advanced through the MCA stenosis. In this case, a 0.014-inch Volcano pressure wire was used. This wire, originally used in cardiology, transduces pressures and estimates regional blood flow. The wire is used to transduce pressures beyond the stenosis MCA segment before and after the angioplasty.

Tips, Tricks & Complication Avoidance • In cardiology, fractional flow reserved (FFR) is used to dictate surgical treatment of coronary artery stenosis. The increased trans-stenotic gradient is measured via the pressure transducer on a 0.014” coronary wire at maximal hyperemia induced by adenosine. Patients with an FFR of less than 0.8 should undergo myocardial revascularization.

There is no prognostic revascularization benefit in patients with moderate stenosis and an FFR greater than 0.8. • Although still under investigation, FFR could be used to assess response to submaximal angioplasty treatment in patients with intracranial atherosclerotic disease.

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Case Overview

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CASE 22.3 Severe Basilar Artery Stenosis: Radial Artery Approach and Submaximal Angioplasty

• A 69-year-old male presented to the emergency department with difficulty speaking, facial droop, and arm weakness. On neurological examination, the patient was alert, oriented, with right facial droop, dysarthric, and right arm weakness. He has a past medical history of

hypertension and diabetes. His long-term medications include aspirin, clopidogrel, statins, and metoprolol. • Computed tomography (CT) was normal. CT angiography demonstrated severe stenosis of the basilar artery (BA). Magnetic resonance imaging demonstrated acute left pontine stroke.

Fig 22.3a  Head CT angiography showing severe BA stenosis.

Fig 22.3b  Acute brainstem stroke.

Fig 22.3c  Artist’s illustration of endovascular treatment of severe BA stenosis with submaximal angioplasty.

Fig 22.3d  Transradial left vertebral artery access.

22  Intracranial Atherosclerotic Disease—Intracranial Angioplasty

Fig 22.3e  Severe basilar artery stenosis.

Fig 22.3f  Microwire crossing stenosis.

Fig 22.3g  Submaximal balloon angioplasty.

Fig 22.3h  Adequate basilar artery revascularization.

Video 22.3  Submaximal angioplasty for symptomatic intracranial stenosis III

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Procedure • The patient underwent cerebral angiography and endovascular management of severe BA stenosis with submaximal angioplasty gradient pressure measurement. The procedure was performed under conscious sedation through a femoral artery approach. 5,000 units of heparin were administered until an activated clotting time of more than 250 was reached. Patient continued taking 350 mg aspirin and 75 mg clopidogrel daily after the procedure.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.027-inch Velocity microcatheter (Penumbra). • 0.014-inch Synchro 2 microguidewire (Stryker). • Gateway 2 x 15 mm balloon angioplasty (Stryker). • 0.014-inch Volcano pressure guidewire. • 8F AngioSeal percutaneous closure device.

This patient presents with brainstem stroke secondary to severe basilar artery atherosclerosis and, despite aggressive medical therapy, he remained symptomatic. Patient had right vertebral artery (VA) occlusion and severe left VA tortuosity. Anticipating difficult access from a transfemoral approach, the procedure was done through a transradial approach. The guide catheter was advanced over the 0.035-inch glidewire into the left VA (V3 segment). Under road map and magnification, the balloon microcatheter and microwire were advanced into the basilar artery. The balloon was positioned at the stenosis and slowly inflated to nominal pressure. The balloon was kept inflated for a period of 5 min. The patient remained neurologically and hemodynamically stable.

Tips, Tricks & Complication Avoidance • It is important to anticipate vascular access difficulties. Patients with intracranial atherosclerotic disease (ICAD) could also have tortuous cervical vessels and a transfemoral approach could be challenging. Radial or brachial artery are excellent approach alternatives when treating posterior circulation ICAD. We prefer right over left radial artery approach because of the ergonomic position in the interventional suite. • Semicompliant coronary balloons are adequate alternatives to Gateway balloon when these are not available.

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• Slow balloon inflation (1 atm/30 s) is preferred over a fast inflation. As long as the patient tolerates, we inflate the balloon slowly up to nominal pressure and keep it inflated for 45 s to 1 min. Followed by a slow deflation (2 atm/30 s). • It is important to maintain adequate balloon position throughout the angioplasty, as inflation balloons could slide distally or proximally and miss the stenosis.

Part V Intracranial Aneurysms

V

23 Primary Aneurysm Coiling

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24 Balloon-Assisted Coiling

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25 Stent-Assisted Coiling

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26 Flow Diversion Treatment of Intracranial Aneurysms

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27 Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)

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28 Novel Aneurysm Neck Reconstruction Devices

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29 Aneurysm Embolization with Liquid Embolic Agents

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30 Endovascular Vasospasm Treatment

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23  Primary Aneurysm Coiling Kunal Vakharia, Adnan H. Siddiqui, and Elad I. Levy

General Description

Neuroendovascular Anatomy

Since the introduction of detachable coils by Guglielmi in 1991, the standard endovascular therapy for cerebral aneurysms has been coil embolization. The benefit of coil embolization in the treatment of ruptured aneurysms was proven in the randomized, controlled International Subarachnoid Aneurysm Trial (ISAT), the results of which were published in 2002. The basic therapy has since evolved with new techniques, including balloon and coil assistance and is considered part of the standard of care. Once the decision is made to approach an aneurysm through an endovascular approach, the endovascular surgeon plans his or her technical approach on the basis of the angiographic anatomy of the aneurysm and its location, including lesion shape, size, neck, and relation to the parent vessel.

The internal carotid artery (ICA) is divided into seven segments. The last three are intradural and can give rise to cerebral aneurysms. The cavernous and carotid cave typically form aneurysms that remain within the cavernous segment, but understanding the relation of the aneurysm to the distal dural ring becomes important when making a risk assessment for subarachnoid hemorrhage risk over a patient’s lifetime. (If the aneurysm is proximal, it has a low rate of subarachnoid hemorrhage because it is outside the dura.) The ophthalmic segment and communicating segments provide the two most common sources of intracranial aneurysms arising from the ICA. The ICA bifurcation leads to the anterior cerebral artery and middle cerebral artery (MCA) branches. According to Yasargil and Rhoton’s understanding of aneurysm formation, aneurysms tend to arise from bifurcations and thus typical locations include the anterior communicating artery, the MCA bifurcation, pericallosal artery, and posterior communicating artery. In the posterior circulation, the basilar terminus and posterior inferior cerebellar artery origin are the two most common sites that require angiographic evaluation.

Evidence for Coil Embolization • The ISAT investigators randomized 2,143 patients with ruptured aneurysms to either microsurgical clipping or endovascular coiling on the basis of intention to treat. This study demonstrated 23.7% of patients in the endovascular group to be dependent or dead versus 30.6% of those in the surgical group, showing a risk reduction of 6.6%. Overall, ISAT demonstrated equivocal results when comparing endovascular versus microsurgical intervention. • Anatomical results of endovascular therapy have improved over the years with progressively good outcomes from initial studies done by Vinuela et al. in 19971 showing 100% occlusion in only 25% of coil-treated aneurysms to studies done by Raymond et al. in 20032 and Mejdoubi et al. in 2006,3 showing > 95% occlusion in > 90% of coil-treated aneurysms. Coil embolization treatment of cerebral aneurysms with endovascular therapy has grown in popularity in U.S. and European centers. • Aneurysm recurrence rates after coiling of unruptured aneurysms vary from 15% to 26.5% in the analysis of studies such as the Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms (ATENA). Factors leading to increased risk of recurrence include neck width > 4 mm, overall sac size (< 3 mm vs. > 3 mm), and presence of intrasaccular thrombus. • In addition, data from the International Study of Unruptured Intracranial Aneurysms (ISUIA) indicate that the rate of cumulative adverse outcomes including stroke and death for endovascular coiling was 9.3%, compared to 13.7% for surgical clipping.

Indications After ISAT demonstrated equivalent results with coiling for ruptured cerebral aneurysms, the indications for aneurysm coiling increased. Ruptured and unruptured aneurysms may be amenable to endovascular therapy. Indications to treat cerebral aneurysms include risk assessments based on patient history, life expectancy, and location and size of the aneurysm. This has been supported by ISUIA and the 2016 Japanese Small Unruptured Intracranial Aneurysm Verification (SUAVe) study, which evaluated the treatment of small (≤ 5 mm) unruptured aneurysms. In addition, changes to aneurysm size and shape may indicate the need to treat. Typically, aneurysms amenable to primary coiling include a favorable neck-to-dome ratio, such as aneurysms with narrow necks of < 4 mm, saccular domes, and more proximal locations. Patients with posterior circulation aneurysms have demonstrated favorable outcomes with endovascular therapy, and these aneurysms may be more approachable via endovascular therapies.

Periprocedural Medications No overt periprocedural medication regimen is required for aneurysm coil embolization. Typically, patients are placed on aspirin, 325 mg daily postoperatively, as an adjunct therapy to prevent platelet aggregation and thrombus formation. If there are concerns for coil extrusion, dual antiplatelet therapy with clopidogrel, 75 mg daily for 3–6 months, can be considered. Dual antiplatelet therapy is typically not indicated for primary aneurysm coiling. If stent-assisted coiling is suggested, this therapy may become a consideration. Systemic heparinization is administered during the procedure because of the inherent risk of intraprocedural thrombus formation. A weight-based intravenous bolus of heparin aimed at an activated clotting time (ACT) of 250–300 s may limit thromboembolic complications. For acute thrombus formation during the procedure, a glycoprotein IIb/ IIIa inhibitor (e.g., eptifibatide) is utilized. Administration of half of a dose of heparin is typically instituted in settings of acute subarachnoid hemorrhage after the first coil deployment.

Specific Technique and Key Steps 1. 2.

3.

4.

5.

A 6 or 8 French (F) sheath is inserted in the femoral artery. After a femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a curved microwire (0.035-inch angled Glidewire, Terumo) into the aorta. This maneuver is completed under fluoroscopic guidance. Depending on the arch anatomy, the guide catheter can be advanced directly over a 0.035-inch angled Glidewire or advanced over a 4–5F intermediate diagnostic catheter, such as a Vitek (Cook Medical) or Berenstein (Cook Medical) catheter. Utmost care should be taken to prevent the microwire, diagnostic catheter, or guide catheter from crossing the stenotic lesion. Cerebral angiography is performed to obtain a baseline set of images of the intracranial vasculature. Three-dimensional digital subtraction angiography with rotational spins can be performed and evaluated to determine the best working angles prior to microcatheter access (Fig. 23.1-23.11, Video 23.1-23.11). Under roadmap guidance, the microcatheter is advanced over the

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6.

7. 8. 9.

10.

11. 12. 13.

14.

microwire and advanced to the aneurysmal neck (Video 23.123.11). The wire is used to cross the aneurysm, and the microcatheter is advanced past the aneurysm. The wire is brought back into the catheter tip, and the catheter is slowly pulled back until it clicks into the aneurysmal dome, as with posterior communicating artery aneurysms (Fig. 23.6, 23.7, Video 23.6, 23.7) or anterior communicating artery aneurysms (Fig. 23.4, 23.5, Video 23.4, 23.5). Another option is to use the microwire to navigate directly into the aneurysmal dome. Using a push–pull technique, the microwire is stabilized as the microcatheter is advanced into the dome of the aneurysm. Optimal microcatheter position is obtained when the tip of the catheter is two-thirds of the way into the aneurysm dome. Framing coils are selected based on aneurysm size and gently advanced into the dome. After the first break (i.e., the first turn of the coil, part of the natural point at which the coil will turn), coil location is verified. Angiographic runs are obtained after coil deployment to confirm position and prior to softer packing coils (Video 23.1-23.11). In unruptured settings, patients are fully heparinized with a goal-ACT of 250–300 s. In ruptured settings, half-dose heparin is administered after the deployment of the first framing coil. After the final coil is detached, the coil pusher wire is slowly withdrawn under fluoroscopic guidance to confirm detachment. If the coil pulls back, detachment is attempted again. The pusher wire is then exchanged out over the microcatheter to advance the last coil remnant further into the dome and prevent coil extrusion. A final (i.e., control) cerebral angiogram is always recommended to assess for smooth synchronized perfusion, looking specifically for delayed capillary filling or other larger occlusion (vessel dropout).

Device Selection In the authors’ and editors’ practice, the following are common set-ups and devices used for aneurysm coil embolization: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy DA XB, Codman Neuro or Benchmark, Penumbra). • 0.035-inch angled Glidewire. • Intermediate 5F-diagnostic catheter (Vitek). • Microcatheter: – Ruptured: typically choose softer tip catheters to be able to visualize and feel coil kickback (SL-10, Stryker Neurovascular; Prowler 4, Codman Neuro) (Fig. 23.3, Video 23.3).

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Unruptured: may warrant a stiffer catheter to be able to push into the dome of aneurysm and coil more effectively (Prowler Select Plus, Codman Neuro; XT 17, Stryker Neurovascular; Headway DUO, MicroVention). • Microwire (Synchro 2, Stryker Neurovascular; Synchro 10, Stryker Neurovascular; Transcend, Stryker Neurovascular). –

Pearls • Catheter selection is paramount. Selecting a softer catheter, such as an SL-10, in ruptured settings may give the surgeon enough tactile and visual feedback to know that a coil is offering significant resistance and should be redeployed. This may prevent intraoperative rupture. • When guide catheter runs are being performed between coil deployments, tighten the rotating hemostatic valve around the microcatheter to prevent it from moving. • A balloon contingency or coiling contingency should be planned in case of intraprocedural rupture. • During coiling, the proximal marker on the coil becomes crucial, especially in relation to skull base landmarks. The proximal marker will serve as a primary marker for the surgeon to visualize pressure while coiling as well as how well the microcatheter tip is painting (i.e., moving back and forth) the coil inside the aneurysmal dome. Maintaining a slow but steady cadence is important when filling the aneurysm dome, and appropriate sizing of framing coils can play an important role in this cadence (Video 23.1-23.11). • When navigating the microcatheter into the aneurysm dome, make sure to prevent the microcatheter from buckling proximally as this may indicate that potentially hazardous force is developing proximally in the microcatheter. Reducing this redundancy prior to selective catheterization the aneurysm is important.

References [1] Vinuela F, Duckwiler G, Mawad M. Guglielmi detachable coil embolization of acute intracranial aneuerysm: Perioperative anatomical and clinical outcome in 403 patients. J Neurosurg. 1997;86(3):475–482. [2] Raymond J, Guilbert F, Weill A, et al. Long-term angiographic recurrences after selective endovascular treatment of aneurysms with detachable coils. Stroke. 2003;34(6):1398–1403. [3] Mejdoubi M, Gigaud M, Tremoulet M, Albucher JF, Cognard C. Initial primary endovascular treatment in the management of ruptured intracranial aneurysms: A prospective consecutive series. Neuroradiology. 2006;48(12):899–905.

23 Primary Aneurysm Coiling

Case Overview

CASE 23.1 Cavernous Internal Carotid Artery Aneurysm: Primary Coiling

• A 43-year-old male presented to the emergency department with acute onset of transient diplopia. On physical examination, he was found to have a left sixth nerve palsy; the rest of his neurological exam was normal. His past medical significant history was relevant for

ulcerative colitis. His father died of a ruptured intracranial aneurysm. He is currently taking no medications. • Computed tomography was normal. CT angiography demonstrated a left cavernous internal carotid artery (ICA) aneurysm.

Fig 23.1a CT angiography showing a left ICA aneurysm.

Fig 23.1b 3D reconstruction CT angiography showing a narrow-necked left ICA aneurysm.

Fig 23.1c Artist’s illustration of primary coiling of cavernous ICA aneurysm.

Fig 23.1d Cavernous ICA aneurysm.

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Fig 23.1e  Aneurysm Microcatheterization.

Fig 23.1f  Coiling.

Fig 23.1g  Complete aneurysm obliteration.

Video 23.1  Coil embolization of cavernous ICA aneurysm

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Procedure • The patient underwent endovascular primary coil embolization of the left cavernous ICA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB guide catheter (Codman). • 0.0156-inch Headway DUO 156 cm microcatheter (Microvention). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Currently, the majority of cavernous and paraclinoid ICA aneurysms are treated with flow diversion. The current patient is an uncommon case of an unruptured symptomatic cavernous ICA aneurysm who presented with a sixth nerve palsy. Because the history of ulcerative colitis and the need of dual antiplatelet regimen, we did not offer flow diversion. Primary coiling is still a very viable option for cavernous ICA aneurysms. This aneurysm in particular had a favorable neck for primary coiling without the need of a stent. A simple 6F guide catheter was accommodated at the upper cervical ICA. A coiling microcatheter was navigated directly into the aneurysm.

Tips, Tricks & Complication Avoidance • Microcatheterization of cavernous or paraclinoid ICA aneurysms, especially on the dorsal wall of the ICA, can be challenging because of the curvature of the carotid syphon. Shape the tip of the microwire as needed (e.g., “tight J,” “pig-tail” shape) to obtain the proper angulation to access the aneurysm.

• A 45° or 90° angle microcatheter is an alternative for easier aneurysm access. • Because of the proximal location of these aneurysms, there is rarely the need for an intermediate catheter, as long as the guide catheter is at or near the petrous ICA segment.

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Case Overview

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CASE 23.2 Internal Carotid Artery Terminus Aneurysm: Primary Coiling

• A 57-year-old male presented to the emergency department with possible transient ischemic attack. Neurological examination was normal. He had a past medical history significant for hypertension and coronary artery disease and recent coronary stenting. Patient has been on dual antiplatelet therapy (aspirin and clopidogrel).

• Computed tomography was normal with no evidence of subarachnoid hemorrhage. CT angiography demonstrated a right internal carotid artery (ICA) terminus aneurysm.

Fig 23.2a  CT angiography showing a right ICA bifurcation aneurysm.

Fig 23.2b  3D reconstruction CT angiography showing a narrow-necked right ICA bifurcation aneurysm.

Fig 23.2c  Artist’s illustration of primary coiling of right ICA terminus aneurysm.

Fig 23.2d  Right ICA terminus aneurysm.

23  Primary Aneurysm Coiling

Fig 23.2e  Distal access catheter (DAC) supporting the microcatheter entering the aneurysm.

Fig 23.2f  Coiling.

Fig 23.2g  Complete aneurysm obliteration.

Video 23.2  Triaxial system for coil embolization of ICA terminus aneurysm

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Procedure • The patient underwent endovascular primary coil embolization of the right ICA terminus aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • Intermediate DAC catheter (Stryker). • Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Bifurcation aneurysms (e.g., ICA terminus, basilar apex) are in general relatively straightforward cases for endovascular treatment; however, some cases could be challenging. The current case of an ICA terminus aneurysm is not centered at the ICA terminus but slightly over to the anterior cerebral artery, making it challenging to catheterize. Even though the guide catheter was positioned at the petrous ICA segment, there was significant “snaking” of the microcatheter. An intermediate catheter was then used to provide support closer to the aneurysm and reduce the “snaking” effect.

Tips, Tricks & Complication Avoidance • The majority of the bifurcation aneurysms are not centered at the bifurcation, they are rather off to one side of the bifurcation arteries. • The use of an intermediate catheter helps by stabilizing the endovascular construct, reducing “snaking” of the microcatheter and facilitating aneurysm catheterization. We do not advocate the

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use of an intermediate catheter for all bifurcations cases, only when necessary. • For ICA bifurcation aneurysms, usually a straight microcatheter with no angulation is adequate and sufficient.

23  Primary Aneurysm Coiling

Case Overview

CASE 23.3 Very Small Ruptured Anterior Cerebral Artery Aneurysm: Primary Coiling

• A 35-year-old male presented to the emergency department complaining of the “worst headache of his life.” Neurological examination was normal, no focal deficits. He had no significant past medical history. Patient was not taking any medications.

• Computed tomography (CT) demonstrated diffuse subarachnoid hemorrhage. CT angiography demonstrated a very small (2 mm) aneurysm on the dorsal wall at the junction of the internal carotid artery (ICA) and anterior cerebral artery (ACA).

Fig 23.3a  CT showing diffuse subarachnoid hemorrhage.

Fig 23.3b  CT angiography demonstrating a 2–3 mm right ICA/ACA aneurysm.

Fig 23.3c  Artist’s illustration of primary coiling of small ruptured ICA/ACA aneurysm.

Fig 23.3d  Right ICA/ACA aneurysm

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Fig 23.3e  0.017-inch Excelsior XT-17 microcatheter (Stryker) not able to access the aneurysm.

Fig 23.3f  0.0165-inch Headway DUO microcatheter (Microvention) within the aneurysm.

Fig 23.3g  Coiling.

Fig 23.3h  Complete aneurysm obliteration.

Video 23.3  Coil embolization of ruptured ACA aneurysm

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23  Primary Aneurysm Coiling

Procedure • The patient underwent endovascular primary coil embolization of the right ICA/ACA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. Only 3,000 units of heparin were given once the first coil was deployed.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • Intermediate DAC catheter (Stryker). • 0.017-inch Excelsior XT-17 microcatheter (Stryker). • 0.0165-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Accessing small aneurysms (< 3 mm) can be challenging. In the current case of a rupture 2 x 3 mm ICA/ACA aneurysm, access was difficult because of the particular location and size of the aneurysm neck. An initial embolization attempt was done with a 0.017-inch microcatheter that could not access into the aneurysm and was not stable enough to coil from outside. A second attempt was performed with a slightly smaller microcatheter (0.0165inch) that allowed stable access into the aneurysm, permitting successful coiling. An ENVOY XB DA was used to obtain adequate distal access and an intermediate DAC catheter to reduce microcatheter “snaking.”

Tips, Tricks & Complication Avoidance • Very small aneurysm sizes may limit endovascular options. Small size makes for challenging aneurysm catheterization, risk of perforation by microcatheters that could load and spring forward, and difficulty placing multiple coils. • A major limitation of the endovascular treatment of small aneurysms is the possibility of intraoperative rupture. Careful microcatheter placement at the neck of the aneurysm and use of the soft coil loop to enter the aneurysm is one of the strategies used for aneurysms coiling.

• Coil chosen has to be the shortest length of soft type to avoid excessive manipulation and tension build-up in the aneurysm. • To prevent rupture of very small aneurysms during coiling, the distal marker of the selected microcatheter preferably should be located near the aneurysmal neck. At the end of coil placement, slow withdrawal of the microcatheter can help avoid any potential injury from the relatively stiff detachment zone. • Do not hesitate to try multiple microcatheter sizes, shapes, and brands.

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Case Overview

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CASE 23.4 Anterior Communicating Artery Aneurysm: Primary Coiling

• A 66-year-old male presented to the emergency department with transient ischemic attack symptoms. Neurological examination was normal. He had significant past medical history of hypertension, smoking, and his mother had died of a ruptured aneurysm.

• Computed tomography (CT) was normal. CT angiography demonstrated a multilobulated anterior communicating artery (ACoA) aneurysm projecting inferiorly.

Fig 23.4a  CT angiography showing an ACoA aneurysm projecting inferiorly.

Fig 23.4b  3D CT angiography reconstruction.

Fig 23.4c  Artist’s illustration of primary coiling of ACoA aneurysm.

Fig 23.4d  Anteroposterior and lateral views of ACoA aneurysm.

23  Primary Aneurysm Coiling

Fig 23.4e  Microcatheter within the aneurysm deploying first coil.

Fig 23.4f  Complete aneurysm obliteration.

Video 23.4  Coil embolization of an ACoA aneurysm I

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Procedure • The patient underwent endovascular primary coil embolization of the ACoA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. Only 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This is a relatively simple narrow-necked ACoA aneurysm to treat with endovascular primary coiling. A simple 6F guide catheter with a standard microcatheter was sufficient to obtain good aneurysm obliteration. Sometimes the simplest solutions offer the best treatment. In this particular case, the anatomy of the aneurysms (size and neck) was favorable for primary coiling.

Tips, Tricks & Complication Avoidance • ACoA aneurysms are one of the most common intracranial aneurysms, the second most common location for ruptured aneurysms, and the most heterogeneous (characteristics, size, projection) of all intracranial aneurysms. • When treating ACoA aneurysms, always perform bilateral internal carotid artery angiography to know the patency and dominance of both anterior cerebral arteries.

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• It is not uncommon that advanced endovascular techniques (balloonor stenting-assisted coiling) are necessary to achieve good results. • Primary coil embolization is still a good option for narrow-necked aneurysms in older patients. Primary coiling has significantly fewer risks than other endovascular techniques. • A disadvantage of primary coiling is the potential risk of aneurysm recurrence; however, it is less significant in elderly patients.

23  Primary Aneurysm Coiling

Case Overview

CASE 23.5 Symptomatic Anterior Communicating Artery Aneurysm: Primary Coiling

• A 50-year-old male presented to the emergency department with “worst headache of his life” associated with photophobia and neck pain. Symptoms have been present for more than 72 h. Neurological examination was normal. He had a significant past medical history of hypertension, smoking, lung cancer under remission, and his father had died of a ruptured aneurysm.

• Computed tomography (CT) was normal with no evidence of subarachnoid hemorrhage (SAH). Lumbar puncture cerebrospinal fluid (CSF) analysis showed xanthochromia. CT angiography demonstrated an anterior communicating artery (ACoA) aneurysm projecting anteriorly with a dominant left anterior cerebral artery (ACA).

Fig 23.5a  3D CT angiography reconstruction showing the ACoA aneurysm.

Fig 23.5b  Artist’s illustration of primary coiling of symptomatic ACoA aneurysm.

Fig 23.5c  Anteroposterior and lateral views of microcatheter access into the ACoA aneurysm.

Fig 23.5d  Coiling.

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Fig 23.5e  Complete aneurysm obliteration.

Video 23.5  Coil embolization of an ACoA aneurysm II

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Procedure • The patient underwent endovascular primary coil embolization of the ACoA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.0165-inch Excelsior SL-10 45° angle microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This is a symptomatic simple narrow-necked ACoA aneurysm amenable to endovascular primary coiling. CT scan did not demonstrate SAH but CSF was positive for SAH. A simple 6F guide catheter with a standard microcatheter was sufficient to obtain good aneurysm access. A 45° angle microcatheter was used for easier access into the aneurysm. In this particular case, the anatomy of the aneurysms (size and neck) was favorable for primary coiling. The risk of recurrence is not zero and follow-up is mandatory.

Tips, Tricks & Complication Avoidance • Ruptured ACoA aneurysms, regardless of size and projection, can be safely treated by both treatment modalities (microsurgery clip ligation and coil embolization) in a large-scale randomized clinical trial. Clinical outcomes and stroke rates did not differ significantly in astreated or intention-to-treat analyses (Neurosurgery. 2015;77(4):566– 571). • When comparing surgical and endovascular treatment, the longterm clinical and neuropsychological outcomes of patients treated for ruptured and unruptured ACoA aneurysms, it was found that the

presence of subarachnoid hemorrhage is more important than the type of treatment in determining the clinical and neuropsychological outcomes of ACoA treatment (Acta Neurochir Suppl. 2017;124:173– 177). • Primary coil embolization is the initial endovascular method to treat ruptured aneurysms, leaving balloon or stents only if needed. • A disadvantage of primary coiling is the potential risk of aneurysm recurrence especially in young patients, and follow-up is mandatory.

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Case Overview

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CASE 23.6 Ruptured Posterior Communicating Artery Aneurysm in a Patient with Complex Aortic Arch Anatomy

• A 79-year-old female presented to the emergency department with the “worst headache of her life,” altered mental status, followed by unresponsiveness. On examination she was unresponsive with eyes closed, pupils 3 mm and reactive, localizing to pain on all extremities, with no obvious focal deficits. Her initial Hunt and Hess score was 4,

requiring intubation. She has a past medical history of hypertension, breast cancer, and chronic pulmonary disease. • Computed tomography (CT) demonstrated severe subarachnoid hemorrhage (Fisher 4) and hydrocephalus. • CT angiogram revealed a large left posterior communicating artery (PCoA) aneurysm.

Fig 23.6a  CT showing severe subarachnoid hemorrhage (SAH) and hydrocephalus.

Fig 23.6b  Head CT angiography demonstrating an elongated left PCoA aneurysm.

Fig 23.6c  Neck CT angiography showing the abnormal, elongated, and rotated aortic arch.

Fig 23.6d (1)  Artist’s illustration of primary coiling of symptomatic anterior communicating artery aneurysm.

23  Primary Aneurysm Coiling

Fig 23.6d (2)  Aberrant arch anatomy.

Fig 23.6e  Abnormal aortic arch anatomy.

Fig 23.6f  Intermediate catheter in the left common carotid artery.

Fig 23.6g  Left PCoA aneurysm.

Fig 23.6h  Left PCoA aneurysm access.

Fig 23.6i  Left PCoA aneurysm coiling.

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Procedure • The patient underwent emergent external ventricular drain and immediately transfered to interventional radiology for endovascular primary embolization. The procedure was performed under general anesthesia and through a right femoral artery approach. 3,000 units of heparin were given once the first framing coil was deployed.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Simmons 2 Glide catheter. • Benchmark 071 intracranial guide catheter (Penumbra). • Vitek catheter (Cook Medical). • 0.0165-inch Excelsior SL-10 45° angle microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Navigation of the aortic arch and obtaining access into the left carotid artery was challenging because of the abnormal anatomy, rotation of the arch, and abnormal origin of the left carotid artery. Multiple catheters and wires were used, including a Simmons 2 catheter, a Vitek catheter, and a Benchmark catheter. After multiple attempts at finding the left carotid artery, an aortogram demonstrated the aberrant origin of the left carotid artery. Once access into the common carotid artery was established, the guide catheter was navigated up to the distal internal carotid artery for a stable construct.

Tips, Tricks & Complication Avoidance • PCoA artery could present with SAH and/or third cranial nerve (CN) palsy. Some vascular neurosurgeons still prefer microsurgery clip ligation for patients presenting with CN palsy. Literature has shown adequate third CN palsy recovery after endovascular (AJNR Am J Neuroradiol. 2013;34(4):828-832) and surgical treatment (Neurosurgery. 2015;77(6):931-939).

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• Arch navigation and adequate access is essential in endovascular neurosurgery. Occasionally, great vessels have an aberrant origin; do not hesitate to perform an aortogram when carotid or vertebral arteries are not easily found. • The most common anatomical aortic arch variant is bovine arch (left and right carotid artery common origin) and dorsal arch origin of the left subclavian artery.

23  Primary Aneurysm Coiling

Case Overview

CASE 23.7 Ruptured Posterior Communicating Artery and Ophthalmic Aneurysms

• A 56-year-old female presented to the emergency department with “worst headache of her life” while having intercourse. Neurologically the patient was lethargic, arouse with pain stimuli, oriented to person only, with eyes closed. Pupils were 3 mm reactive and symmetric. Not following commands but localizing to pain bilaterally. No focal

neurological deficits. Her Hunt and Hess was 4. Patient was intubated to protect airway. • Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) (Fisher 4) and hydrocephalus. CT angiography demonstrated a posterior communicating artery (PCoA) and a ophthalmic artery aneurysm .

Fig 23.7a  CT showing severe SAH and mild hydrocephalus.

Fig 23.7b  CT angiography demonstrating a right PCoA (red arrow) and ophthalmic artery (blue arrow) aneurysms.

Fig 23.7c  3D reconstruction of CT angiography demonstrating both aneurysms.

Fig 23.7d  Artist’s illustration of primary coiling of ruptured PCoA and ophthalmic artery aneurysms.

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Fig 23.7e  Lateral angiogram showing both intracranial aneurysms.

Fig 23.7f  PCoA aneurysm coiling.

Fig 23.7g  Ophthalmic artery aneurysm catheterization with catheter balloon support.

Fig 23.7h  Ophthalmic aneurysm coiling.

Fig 23.7i  Successful aneurysms obliteration.

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23  Primary Aneurysm Coiling Video 23.7  Coil embolization of multiple intracranial aneurysms

Procedure • The patient underwent endovascular primary coil embolization of both intracranial aneurysms. The procedure was performed under general anesthesia and through a right femoral artery approach. 3,000 units of heparin were given once the first framing coil was detached in the first aneurysm.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy DA XB guide catheter (Codman). • 0.0165-inch Excelsior SL-10 45° angle microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • Scepter C balloon (Microvention). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Management of multiple intracranial aneurysms in the presence of diffuse SAH can be challenging. The presence of a hematoma or large amounts of SAH in the vicinity of a specific aneurysm suggests the culprit. In this case, SAH is diffuse throughout the basal cisterns and Sylvian fissures. Both intracranial aneurysms are in the same internal carotid artery in close approximation to each other. Therefore, we are obligated to treat both. Although we have an intracranial balloon ready for balloonassisted coiling, primary coiling was sufficient to obtain adequate results. Both aneurysms were treated with the same microcatheter and microwire. Systemic heparin was given once the PCoA aneurysm was secure with an initial coil.

Tips, Tricks & Complication Avoidance • Multiple intracranial aneurysms can be treated during the same endovascular procedure, especially if both aneurysms are located on the same side and circulation. • Based on statistics and hemodynamics, PCoA and anterior communicating artery aneurysms tend to rupture more frequently; therefore, the PCoA aneurysm was coiled first followed by the ophthalmic artery aneurysm.

• There is no specific protocol for heparin administration when treating ruptured aneurysms. Our preference is to give heparin once the initial framing coil has secured the aneurysm. • If the aneurysm had not been ruptured, other alternatives in management would have included a single flow diversion stent or microsurgical clip ligation to treat both aneurysms.

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Case Overview

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CASE 23.8 Large Posterior Inferior Cerebellar Artery Aneurysm

• A 49-year-old female was transferred to the emergency department after a motor vehicle accident. Her symptoms included severe occipital headache and neck soreness. She had a normal neurological examination and no past medical history of significance.

• Computed tomography (CT) was normal. CT angiography showed a large posterior inferior cerebellar artery (PICA) aneurysm. • The patient was discharged home and brought back for endovascular coiling of PICA aneurysm.

Fig 23.8a  Rotational angiography of the left VA showing the large PICA aneurysm.

Fig 23.8b  3D reconstruction of CT angiography showing PICA aneurysm anatomy.

Fig 23.8c  Artist’s illustration of primary coiling of PICA aneurysm.

Fig 23.8d  Lateral angiogram showing PICA aneurysm.

23  Primary Aneurysm Coiling

Fig 23.8e  Maneuvering microcatheter into aneurysm.

Fig 23.8f  Catheterization of aneurysm.

Fig 23.8g  Coiling.

Fig 23.8h  Complete aneurysm obliteration.

Video 23.8  Coil embolization of a PICA aneurysm

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Procedure • The patient underwent endovascular primary coil embolization of PICA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to achieve an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.0165-inch Excelsior SL-10 45° angle microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

It is always important to obtain a 3D reconstruction angiography to evaluate the characteristics of the aneurysm, precise size, and the relation with the parent artery and branches. The standard anteroposterior and lateral angiogram views of this particular PICA aneurysm showed PICA being incorporated within the aneurysm. However, 3D reconstruction demonstrated that PICA is not in intimal relation with the aneurysms and coil is a safe option. A standard 6F catheter was used to obtain access at V3 segment of the vertebral artery (VA). Envoy XB DA catheter has a soft 10cm distal tip, less traumatic to vessels and a very good alternative for VA access. Once access has been established, a standard microcatheter and microwire are used to access the aneurysm. Because PICA is not incorporated within the neck of the aneurysm, we advocate dense packing of the aneurysm including the neck.

Tips, Tricks & Complication Avoidance • The VA is a fragile artery and any minor trauma could dissect or injure the vessel. We recommend the use of soft 6F guide catheters (ENVOY XB DA [Codman], Benchmark [Penumbra]). • If the anatomy of the aneurysm and the relation with the parent artery and branches is not well understood, obtain a 3D reconstruction angiogram. • When obtaining access into an aneurysm always keep the microcatheter at the promixal half of the aneurysm; once the

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microwire is removed, the microcatheter will move forward. If the microcatheter is in close proximity to the aneurysm dome before the wire is removed, it increases the risk of aneurysm rupture; therefore, pull the microcatheter slightly before removing the microwire. • Posterior circulation aneurysms have the highest rate of recurrence after endovascular coiling. If safe and feasible, we advocate complete dense aneurysm coil packing.

23  Primary Aneurysm Coiling

Case Overview

CASE 23.9 Recurrent Posterior Inferior Cerebellar Artery Aneurysm

• A 58-year-old female had a ruptured posterior inferior cerebellar artery (PICA) aneurysm treated with endovascular coiling. Patient recovered completely from the subarachnoid hemorrhage (SAH). Patient has past medical history of hypertension and tobacco.

• On a 3-year follow-up, magnetic resonance imaging showed the aneurysm had recurred significantly. • Because the previous history of SAH, posterior circulation (PC) location, and comorbidities (hypertension and tobacco), treatment is necessary.

Fig 23.9a  Magnetic resonance angiography (MRA) showing the left PICA aneurysm recurrence.

Fig 23.9b  Artist’s illustration of primary coiling of recurrent PICA aneurysm.

Fig 23.9c  Lateral angiogram showing PICA aneurysm recurrence.

Fig 23.9d  Catheterization of aneurysm.

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Fig 23.9e  Coiling.

Fig 23.9f  Small residual requiring more coils.

Fig 23.9g  Complete aneurysm obliteration with adequate PICA patency.

Video 23.9  Coil embolization of a recurrent PICA aneurysm

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Procedure • The patient underwent endovascular primary coil embolization of recurrent left PICA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to achieve an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

The incidence of aneurysm recurrence is higher in posterior circulation. The current patient had a recurrent PICA aneurysm after endovascular coiling. PICA is intimately related with the aneurysm neck making dense coil aneurysm packing challenging. Once access in the vertebral artery was established, a microcatheter is advanced in the aneurysm neck. Microcatheterization of aneurysm neck recurrence can be challenging and at times, the coiling process is done with the microcatheter just outside the aneurysm. In the current case, two coils were necessary to complete aneurysm’s obliteration. An angiogram run was done before each coil detachment to assess PICA patency.

Tips, Tricks & Complication Avoidance • Ruptured PC aneurysms have the highest rate of recurrence after endovascular primary coiling. Majority of PC aneurysms are treated endovascularly. Rupture PC aneurysms could initially be coiled to prevent immediate re-rupture; once patient is stable and recovered from the SAH, a definite treatment with additional stent-assisted coiling or flow diversion is advocated.

• Follow-up after endovascular primary coil of posterior aneurysms is essential. Patients should be seen at 6 months, 1 year, 2, years, 3 years, 5 years, and 10 years after the initial procedure. MRA or CTA are sufficient for general screening but digital subtraction angiography is necessary to understand aneurysm recurrence and procedure planning.

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Case Overview

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CASE 23.10 Aneurysm of the Basilar Artery and Posterior Cerebral Artery Junction: Primary Coiling

• A 47-year-old female with daily chronic headaches was found to have multiple posterior circulation intracranial aneurysms. Neurological examination was normal. Patient has hypertension and familial history of rupture aneurysms.

• Magnetic resonance (MR) angiography demonstrated a large aneurysm at the junction of the right basilar artery (BA) and posterior cerebral artery (PCA), and a small left superior cerebellar artery (SCA) aneurysm.

Fig 23.10a  MR angiography showing both posterior circulation aneurysms.

Fig 23.10b  Artist’s illustration of primary coiling of BA/PCA juntion aneurysm.

Fig 23.10c  Access into the left vertebral artery.

Fig 23.10d  3D angiogram reconstruction showing the right BA/PCA junction and left SCA aneurysms.

23  Primary Aneurysm Coiling

Fig 23.10e  Right BA/PCA aneurysm access.

Fig 23.10f  Coiling.

Fig 23.10g  Complete aneurysm obliteration.

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V  Intracranial Aneurysms Video 23.10  Coil embolization of a basilar artery aneurysm

Procedure • The patient underwent elective endovascular primary coiling embolization of right BA/PCA junction aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Excelsior XT-17 FLEX 45° angled tip microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This is a young patient with high risk of aneurysm rupture (familial history and aneurysms location), and treatment is strongly advised. We decided to treat the right PCA/BA first because of its larger size. The location and origin of the aneurysm is not clear on conventional MRA or angiography, a 3D spin reconstruction assisted in understanding and obtaining working views. The exact origin is the junction of the PCA and BA. A microcatheter was navigated into the aneurysm and three coils (one framing and two helical) were sufficient to obliterate the aneurysm. Coil mass was kept away from the right PCA to prevent artery occlusion. A balloon or stent were ready in case we needed them to assist the coiling and maintain the PCA open. At the end of the coiling, there was a coil loop protruding in the PCA without limiting flow. The patient was started on aspirin to prevent thrombus formation and possible distal PCA ischemic strokes.

Tips, Tricks & Complication Avoidance • It is crucial to understand the exact origin of the aneurysm and neck anatomy. Obtaining 3D digital subtraction angiography is strongly recommended to obtain ideal working views.

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• Multiple nonruptured aneurysms embolization during the same endovascular procedure is doable but not recommended. Single aneurysm treatments reduce the overall risks (rupture, stroke, artery occlusion).

23  Primary Aneurysm Coiling

Case Overview

CASE 23.11 Dissecting Frontopolar Artery Aneurysm: Parent Vessel Occlusion

• A 55-year-old female presented to the emergency department with acute severe thunderclap headache. On physical examination she was neurologically intact. She had no past medical history of importance.

• Computed tomography (CT) demonstrated small subarachnoid hemorrhage at the base of the right frontal lobe and along the interhemispheric fissure. • CT angiography demonstrated a possible right distal anterior cerebral artery aneurysm.

Fig 23.11a  CT showing subarachnoid hemorrhage at the interhemispheric fissure.

Fig 23.11b  CT angiography showing the frontopolar dissecting aneurysm.

Fig 23.11c  Artist’s illustration of parent vessel occlusion for dissecting frontalpolar artery aneurysm.

Fig 23.11d  Dissecting frontopolar artery aneurysm.

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Fig 23.11e  Aneurysm microcatheterization.

Fig 23.11f  Coiling.

Fig 23.11g  Magnetic resonance imaging 24 h after embolization demonstrated no acute stroke.

Fig 23.11h  Complete aneurysm obliteration; a 6-month angiography follow-up.

Video 23.11  Coil embolization of a dissecting distal anterior cerebral artery aneurysm

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23  Primary Aneurysm Coiling

Procedure • The patient underwent endovascular primary embolization of the frontopolar aneurysm and artery. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB guide catheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Microvention). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Parent vessel occlusion is a common procedure in the treatment of intracranial vascular diseases, including dissecting aneurysm. Because of the distal location of the current frontopolar artery aneurysm, there was no need for balloon test occlusion. Extensive collaterals to the region are sufficient to allow frontopolar artery occlusion with no ischemic consequences. A 6F guide catheter was positioned at the internal carotid artery. Under road map and magnification, a microcatheter was advanced into the dissected segment of the frontopolar artery. Multiple coils were placed in the aneurysm until obliteration of the aneurysm and parent vessel was obtained. The patient remained neurologically intact throughout the procedure. At the end of the procedure, the parent artery was still flowing but with very slow flow, ultimately allowing for collaterals to take over that region in a slow fashion preventing acute ischemic stroke.

Tips, Tricks & Complication Avoidance • Parent vessel occlusion has been an adequate endovascular alternative in the management of dissecting intracranial and extracranial aneurysms. Large parent vessel occlusion requires balloon test occlusion to assess for collaterals and the need for a revascularization procedure. In general, distal vascular territories do not require balloon

test occlusion because of significant collateralization; these territories include distal anterior cerebral and posterior cerebral arteries. • We strongly recommend parent vessel occlusion with coils only, without the use of liquid embolic agents. Coils will not occlude the artery abruptly and completely, rather partially and slowly to allow for collateralization and decreasing the risk of acute ischemic stroke.

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24  Balloon-Assisted Coiling Leonardo Rangel-Castilla and Giuseppe Lanzino

Ascent balloons have a 4 mm or 6 mm diameter and are 7–15 mm in length with a tip length of 3 mm.

General Description Balloon-assisted techniques for aneurysm coiling are essential for endovascular neurosurgeons. Balloon-assisted coiling is mainly used for aneurysm neck remodeling and side branch protection. A balloon also stabilizes the coiling microcatheter within the aneurysm by preventing “kickback” of the microcatheter and obtaining more dense packing of the coils. For wide-necked aneurysms, balloon-assisted coiling can prevent the need for a stent; this can be very helpful in the case of a subarachnoid hemorrhage from ruptured aneurysms. Also, a balloon can be used as a safety net in case of intraoperative aneurysm rupture. A double-lumen balloon catheter allows for coil embolization and neck reconstruction by a single microcatheter.

Indications Balloon-assisted coiling is indicated for the endovascular management of ruptured or unruptured narrow or wide-necked aneurysms. Some neurosurgeons always have a balloon handy in the event of aneurysm rupture.

Neuroendovascular Anatomy Wide-necked aneurysms can be located anywhere in the intracranial circulation, including the paraophthalmic region, middle cerebral artery, anterior communicating artery, vertebral artery (VA), and basilar artery. The anatomy of each aneurysm should be analyzed on a case-by-case basis. Then the interventionist can decide whether balloon-assisted coiling is the best option. Aneurysms located at the basilar apex or the bifurcation of the internal carotid artery (ICA), middle cerebral artery, or anterior communicating artery can have a wide neck or project predominantly toward one arterial branch, and the need for balloonassisted coiling might be necessary.

Perioperative Medication Balloon-assisted coiling is usually performed under heparinization. There is no need for antiplatelet therapy.

systemic

Intracranial Balloons Balloons are classified as compliant and noncompliant. Compliant balloons are inflated slowly by hand and conform to the contours of the aneurysm neck and parent vessels and branches. Noncompliant balloons are not used for balloon-assisted coiling. Compliant balloons that have a single lumen include the HyperGlide (Medtronic), HyperForm (Medtronic), Transform (Stryker), and Transform Super Compliant (Stryker). The diameters of these balloons range from 3 to 7 mm. The lengths range from 10 to 30 mm. The HyperForm and the Transform Super Compliant are highly conformable. This feature of adapting to the arterial anatomy allows these balloons to partially herniate into the aneurysm, which is very useful when the parent artery is in close proximity to or involved with the neck of the aneurysm. Compliant balloons that have a double coaxial lumen include the Scepter (MicroVention) and Ascent (Codman). Scepter balloons have a 4 mm diameter and are 10–20 mm in length with a tip length of 5 mm.

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Specific Technique and Key Steps 1. Endovascular access is obtained via a femoral arteriotomy with a micropuncture set. Under fluoroscopic visualization, a microwire is advanced through a transitional 6 French (F) dilator to the desired location in relation to the femoral head. 2. A 6–8 F guide sheath with a copilot valve is placed in the ICA or VA, depending on the aneurysm’s location. This can be done using a sliding catheter (e.g., Vitek catheter, Cook) or via an exchange wire, such as a 0.035-inch exchange length Glidewire (Terumo). Roadmapping technique is used for this process. 3. Initial digital subtraction angiography (DSA) runs of anteroposterior and lateral views are performed. Oblique magnified working views are obtained from a rotational 3D reconstruction of the DSA runs (Fig. 24.1-24.3, Video 24.1-24.3). 4. If the aneurysm is distal or located in tortuous anatomy, a triaxial catheter system consisting of a guide catheter, an intermediate catheter, and a microcatheter is utilized for access to the aneurysm; otherwise, a biaxial catheter access system consisting of a guide catheter and a microcatheter will suffice. 5. If a triaxial system is utilized, the intermediate catheter must be large enough to hold both the coiling microcatheter and the balloon microcatheter. In the case of a basilar apex aneurysm, one microcatheter can be navigated through one VA, and the balloon can be navigated through the contralateral VA. 6. Before introducing the balloon into the patient, the balloon is prepared on the back table according to lumen type (double or single). Following its introduction, a single-lumen balloon requires a microwire in place at all times, because if that microwire is removed, air or blood will fill the balloon and it will no longer be visible. Balloon size is based on parent vessel size. Typically, a compliant balloon is utilized for coiling because it conforms to the ostia of the parent vessel and protects the neck of the aneurysm (Video 24.1-24.3). 7. Typically, the balloon is placed through a separate rotating hemostatic valve on the guide sheath; however, the copilot valve of the guide sheath can also be utilized. Under roadmap working views, the balloon is navigated just distal to the aneurysm. A test inflation can be performed with a 1-mL or 3-mL syringe filled with contrast material to see whether the balloon is visible and how the contrast material travels once the balloon inflated. 8. After the balloon has been tested, it is deflated. The coiling microcatheter (e.g., SL-10, Stryker Neurovascular; DUO, MicroVention) is carefully navigated over the microwire into the aneurysm of choice (Video 24.1-24.3). 9. The aneurysm volume is calculated using the measured width, length, and height, and the appropriate coils are selected. A framing coil is often inserted first, followed by filling coils. 10. HyperForm balloons are elliptical and more compliant than HyperGlyde balloons, which are ideal for cases in which asymmetric inflation is needed. HyperGlide balloons are oblong and elongated. As mentioned previously, these balloons allow some aneurysm herniation and are ideal for sidewall aneurysms such as ICA aneurysms. 11. A more natural coil deployment is possible with the balloon deflated. Coil material that is prolapsing is resheathed, and the

24  Balloon-Assisted Coiling balloon is inflated over the neck of the aneurysm, thus jailing the catheter within. 12. Once the coiling microcatheter is inside the aneurysm and the balloon is inflated, the coils are carefully placed under continuous roadmap working views. If the balloon is occlusive, it will need to be deflated intermittently to restore flow. The aneurysm should be coiled until no contrast material is visible within the interstices of the coil mass (i.e., 30%–40% packing density). 13. Once finished deploying coils, the balloon is slowly deflated and withdrawn under fluoroscopy monitoring to note coil stability. If stable, the balloon is reinflated, the coiling catheter removed, and the balloon is deflated and removed. 14. Final runs are then obtained in anteroposterior and lateral views.

Device Selection In our practice, the following are common set-ups and devices used during balloon-assisted coiling. • 21-gauge micropuncture set, Cope Mandril wire (Cook Medical), 6F dilator, 6–8F sheath. • Neuron or Neuron MAX 90 cm guide catheter (Penumbra) or Envoy XB DA guide catheter (Johnson & Johnson). • Vitek or 125-cm 5F Vertebral catheter (Cook) or 280-cm Glide exchange wire. • 0.035-inch Glidewire. • Intermediate catheter, such as Sofia (MicroVention), Navien (Medtronic), or Catalyst (Stryker). • SL-10 microcatheter (straight, J, 45° or 90° varieties) or DUO microcatheter. • Standard or soft wire Synchro 2 (Stryker). • Continuous heparinized saline. • Platinum coils (hydrogel coils can also be used) (i.e., Cosmos framing coil and hypersoft fillers, MicroVention). • Single-lumen HyperForm or HyperGlide balloon or double-lumen Scepter XC balloon.

Pearls • An invisible balloon is a dangerous balloon. Always test a balloon on the back table to make sure it is intact (inflates and deflates properly; no leaks) and that no air is within. Once a single-lumen balloon is introduced, do not remove the microwire from it. • If a perforation is present while coiling, the balloon can be inflated immediately for hemostasis. • If by accident, the microcatheter perforates the aneurysm, begin coiling extravascularly outside the aneurysm and continue delivering the coil inside the aneurysm with the balloon inflated. • Always use micromovements when catheterizing an aneurysm. • Position the catheter two-thirds of the way into the aneurysm and be mindful of tension in the access system. • A balloon can rupture a vessel if it is too large for that vessel. • If the intervention is performed with the patient awake, be considerate of the fact that an overinflated balloon can be painful and some patients will not tolerate it for long periods of time. • At times, after coiling is performed and the balloon is deflated, a loop or tail of a coil can prolapse into the parent vessel. Aspirin prophylaxis will be needed to prevent emboli formation. • The balloon and microcatheter can push against one another, especially in small vessels. This increases the risk of emboli formation. Glycoprotein IIb/IIIa inhibitors can be utilized to treat emboli formation. • Always be mindful of extravasation. • Coils that are too large should be resheathed. It is dangerous to try to pack excess coils into the aneurysm. • If a long tail of a coil or a mass of coils prolapses despite balloon use, a stent may be necessary. If coils prolapse and embolize, they should be retrieved with a snare. • Hydrogel coils will swell. No. 10 coils are smaller than No. 18 coils and will have a lower packing density per coil. • Transcirculation approaches can be utilized for balloon placement by way of a separate groin puncture. • If catheter kickback is encountered during coiling, the inflated balloon can be minimally deflated, and the coil can be guided back into the aneurysm. The balloon can then be utilized to secure the catheter again.

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Case Overview

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CASE 24.1 Large Anterior Communicating Artery Aneurysm: Balloon-Assisted Coiling

• A 60-year-old male presented to the emergency room with acute severe headache, nausea, vomiting, and paresthesias on the right upper extremity. On neurological exam, he was awake, alert, oriented to person and place, following commands bilaterally, with normal motor strength. There were no focal signs. His initial Hunt and Hess grade was 2. Past medical history was significant for hypertension.

• Computed tomography (CT) showed interhemispheric fissure subarachnoid hemorrhage (SAH) and hematoma. CT angiography demonstrated a large anterior communicating artery (ACoA) aneurysm.

Fig 24.1a  CT scan showing interhemispheric hematoma.

Fig 24.1b  CT angiography demonstrating the large ACoA aneurysm.

Fig 24.1c  Artist’s illustration of balloon-assisted coiling of a large ruptured ACoA aneurysm.

Fig 24.1d  Anteroposterior and lateral angiogram showing the large ACoA aneurysm.

24  Balloon-Assisted Coiling

Fig 24.1e  Intracranial balloon positioning.

Fig 24.1f  Catheterization of aneurysm.

Fig 24.1g  Coiling.

Fig 24.1h  Aneurysm obliteration with adequate bilateral A2 arteries patency.

Video 24.1  Balloon-assisted coiling of a ruptured ACoA aneurysm I

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V  Intracranial Aneurysms

Procedure • The patient underwent endovascular balloon-assisted coiling embolization of a large ACoA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 3,000 units of heparin were given after the first frame coil was deployed.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 Guide catheter (Penumbra). • Compliant TransForm balloon catheter 3 x 15 mm (Stryker). • 0.0165-inch Prowler Select LP ES microcatheter (Codman). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

ACoA aneurysms are the most common intracranial aneurysms and are responsible for nearly 40% of cases of aneurysmal SAH. Endovascular coiling of wide-necked aneurysm can be challenging. Balloon remodeling techniques are used more frequently for ruptured aneurysms. In the current case, after obtaining access in the internal carotid artery, multiple angiography runs were done to find the optimal view of the neck aneurysm. A compliant intracranial balloon (TransForm) was positioned at the aneurysm neck and a second microcatheter into the aneurysm. Prior to balloon inflation, an initial coil loop(s) were deployed in the aneurysm. Once the balloon was inflated, we continued with coiling until complete obliteration of the aneurysm was achieved. Inflation of the balloon also helped with stabilization of the coiling microcatheter during coil deployment. This, in turn, can aid in achieving a more dense packing, thereby minimizing the risk of coil compaction in wide-necked aneurysms.

Tips, Tricks & Complication Avoidance • Ruptured ACoA aneurysms often demonstrate complex morphological features such as variable dome angle projection, involvement of branch and daughter (A2) vessels, and proximity to critical perforators. Classic indications for clipping include variables such as dome-to-neck ratio, complex branch vessel morphology, surgical hematomas, lesions too small to coil, multiple anterior circulation aneurysms, young patient age, and large or giant aneurysms. • Balloon remodeling for the endovascular treatment of complex widenecked aneurysms has evolved over the past two decades. With

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recent trials demonstrating equipoise in reported intraprocedural complication rates when compared with primary coil embolization, its indications have expanded to more anatomically complex lesions including bifurcation aneurysms. • Bilateral access is often helpful and sometimes required for full visualization of the anterior cerebral artery and ACoA complex, including bilateral A2 arteries, and for navigation of the balloon catheter. Ipsilateral and contralateral trajectories for the balloon catheter can be used.

24  Balloon-Assisted Coiling

Case Overview

CASE 24.2 Large Middle Cerebral Artery Aneurysm: Balloon-Assisted Coiling

• A 58-year-old male was taken to the emergency room after found down unresponsive. Patient was intubated on the field. Neurologically he was intubated, eyes open and localizing bilaterally to pain stimuli and with right side hemiparesis. Patient’s religion (Jehovah’s Witnesses) does not allow for blood transfusion if needed.

• Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) and large left frontotemporal intraparenchymal hemorrhage (IPH) with mass effect. • CT angiography demonstrated a large wide-necked middle cerebral artery (MCA) aneurysm.

Fig 24.2a  CT scan showing diffuse SAH and large hematoma.

Fig 24.2b  CT angiography demonstrating the large MCA aneurysm.

Fig 24.2c  3D CT angiography reconstruction of the wide-necked left MCA aneurysm.

Fig 24.2d  Artist’s illustration of balloon-assisted coiling of a large ruptured MCA aneurysm.

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V  Intracranial Aneurysms

Fig 24.2e  Angiogram showing the large wide-necked MCA aneurysm. Both M2 branches are incorporated within the aneurysm, especially the inferior M2 branch.

Fig 24.2f  Balloon inflated covering the inferior M2 branch (arrows) while coiling.

Fig 24.2g  Intermittent balloon inflation.

Fig 24.2h  Aneurysm coiled with neck remnant.

Fig 24.2i  Postoperative CT scan showing adequate hematoma evacuation.

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24  Balloon-Assisted Coiling Video 24.2  Balloon-assisted coiling of a ruptured MCA aneurysm

Procedure • The patient underwent endovascular balloon-assisted coiling embolization of large MCA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 3,000 units of heparin were given after the first frame coil was deployed. After the aneurysm was successfully coiled, the patient underwent left craniotomy for hematoma evacuation.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA Guide catheter (Codman). • Compliant TransForm balloon catheter 3 x 10 mm (Stryker). • 0.0165-inch Excelsior SL-10 (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

Ruptured MCA aneurysms presenting with IPH should be considered surgical candidates for hematoma evacuation and microsurgical clip reconstruction. In the current case, patient’s religion prohibited blood transfusion in case necessary, therefore, open vascular surgery was not an option without significant risks. The patient was taken for emergent coil embolization followed by surgical hematoma evacuation. Endovascular balloon-assisted coil embolization was the technique used. A compliant balloon was positioned at the inferior M2 branch and a coiling microcatheter within the aneurysm. Several coil loops were introduced in the aneurysm before balloon inflation. Multiple coils were deployed to achieve a Raymond-Roy 2 occlusion, follow by surgical evacuation of the hematoma. Once the patient is neurologically stable and recovered from the hemorrhage, definite aneurysm treatment is necessary, including stent-assisted coiling, flow diversion stent, or microsurgical clip ligation.

Tips, Tricks & Complication Avoidance • Surgical clipping is preferred to endovascular coil embolization for the treatment of MCA aneurysms unless aneurysm’s (fusiform) or patient’s (clinical condition) factors strongly favor endovascular techniques. • For wide-necked ruptured aneurysm, initial endovascular balloonassisted coiling leaving a neck remnant is sufficient to reduce the

risk of re-rupture. Do not achieve for Raymond-Roy 1 initially as this could occlude the parent vessel or branch arising near the aneurysm neck. Once the patient is recovered from the SAH, a definite treatment (stent-assisted coiling or flow diversion) is necessary.

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Case Overview

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CASE 24.3 Ruptured Anterior Communicating Artery Aneurysm:Balloon-Assisted Coiling

• A 44-year-old male presented to the emergency room after 4 days of severe headaches. On neurological exam, the patient was awake, alert, confused, oriented to person only, eyes open spontaneously and following commands bilaterally. No focal deficits. His initial Hunt and Hess score was 3.

• Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH). • CT angiography demonstrated an anterior communicating artery (ACoA) aneurysm.

Fig 24.3a  CT scan showing diffuse SAH.

Fig 24.3b  CT angiography demonstrating the ruptured ACoA aneurysm.

Fig 24.3c  Artist’s illustration of balloon-assisted coiling of a ruptured ACoA aneurysm.

Fig 24.3d  Angiogram showing the ACoA aneurysm.

24  Balloon-Assisted Coiling

Fig 24.3e  Intracranial balloon catheter positioned first.

Fig 24.3f  Intermittent balloon inflation.

Fig 24.3g  Balloon inflated prior to coiling.

Fig 24.3h  Coiling.

Fig 24.3i  Successful coil embolization.

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V  Intracranial Aneurysms Video 24.3  Balloon-assisted coiling of a ruptured ACoA aneurysm II

Procedure • The patient underwent endovascular balloon-assisted coiling embolization of ruptured ACoA aneurysm. The procedure was performed under conscious sedation and through a right femoral artery approach. 3,000 units of heparin were given after the first frame coil was deployed.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 7F dilator. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • Compliant TransForm balloon catheter 3 x 15 mm (Stryker). • 0.0165-inch Excelsior SL-10 (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple intracranial coils. • 8F AngioSeal percutaneous closure device.

This particular rupture ACoA aneurysm has a wide neck, has an elongated shape, and a daughter sac at the distal end (probably the rupture site). Both A2 arteries arise from a single A1, therefore it is imperative to maintain patent the only A1 artery. A compliant intracranial balloon was advanced into the inferior A2 branch, a second microcatheter was advanced into the aneurysm. The balloon was the inflated and multiple coils were inserted in the aneurysm. There was a residual aneurysm neck that was not covered by coils. Complete aneurysm occlusion was not possible without running the risk of coil migration and possible parent vessel occlusion once the balloon was deflated. At this point, the aneurysm is secured with very low risk of re-rupture; however, further definite treatment is required.

Tips, Tricks & Complication Avoidance • While we used to use single-lumen balloons navigated over a 0.010 wire, more recently designed double-lumen balloons such as Scepter C (MicroVention) and Ascent (Micrus) that are navigated over a 0.014 wire may facilitate balloon navigation to the anterior cerebral artery and across the ACoA complex. • TransForm balloon can be compliant or supercompliant. Balloon size ranges from 3 x 10 mm to 5 x 30 mm. Supercompliant balloon also come in 7 mm diameter. This particular balloon provides fast deflation, allowing for higher contrast levels, increased visibility, and reduced procedure times.

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• Another excellent intracranial balloon option is a HyperGlide (Medtronic) balloon. The decision to use a HyperGlide versus HyperForm balloon is primarily dependent on the morphology of the aneurysm neck, as well as its relationship to the parent vessel. For approaches to the ipsilateral A1–A2 junction, a HyperGlide balloon will often suffice for protection of the parent vessel with an ipsilateral trajectory. When additional compliance is necessary, most notably in cases of a contralateral trajectory, a HyperForm balloon is often preferable because of its ability to herniate into the neck of the aneurysm while protecting the contralateral A1–A2 junction.

25  Stent-Assisted Coiling Stephan A. Munich, Elad I. Levy, and Adnan H. Siddiqui

General Description Stent-assisted coiling for the treatment of intracranial aneurysms first was reported by Higashida et al. in 1997.1 In that case, a basilar artery aneurysm was treated by deploying a balloon-mounted cardiac stent within the parent artery and coiling the aneurysm by way of catheterization through the stent tines. A year later, Mericle et al.2 followed with a description of the technique for an internal carotid artery aneurysm. Since these early reports, the development of intracranialspecific stents has increased the feasibility and use of stent-assisted coiling for the treatment of intracranial aneurysms.

Evidence Traditionally, stent-assisted coiling has been reserved for wide-necked aneurysms that are not amenable to primary coiling. Contemporary series by Hetts et al.3 and Feng et al.,4 comparing stent-assisted coiling to primary coiling alone, have demonstrated its safety and efficiency. No difference was found in thromboembolic events, hemorrhagic complications, or procedure-related morbidity. Similarly, there was no statistical significance in initial complete occlusion or recanalization. A systematic review and meta-analysis found improved rates of angiographic occlusion and progressive thrombosis and a reduced rate of recurrent aneurysms treated with stent-assisted coiling, compared to those treated with primary coiling.4 Because of the need for dual antiplatelet therapy, the use of stentassisted coiling in the setting of an acute subarachnoid hemorrhage traditionally has been met with apprehension. Although, in general, periprocedural morbidity are similar to those of primary coiling, an analysis performed by Bodily et al.5 found hemorrhagic complications to occur in 8% of patients (a rate higher than reported in the literature for primary coiling). For acutely ruptured intracranial aneurysms, stentassisted coiling remains controversial.

Indications Stent-assisted coiling typically has been reserved for wide-necked unruptured aneurysms. A wide aneurysm neck is defined as a neck diameter > 4 mm and a dome-to-neck ratio of < 2. In the case of a widenecked aneurysm, the stent provides a buttress, which prevents coil herniation into the parent vessel. A large tertiary care center reported increased coil packing density with stent-assisted coiling compared to primary coiling alone.6

Neuroendovascular Anatomy Stent-assisted coiling has been utilized in most locations around the circle of Willis where intracranial aneurysms occur. It is critical to assess the anatomy of the parent vessel in which the stent will be placed. Measurement of the vessel diameter with correct sizing of the stent is necessary to obtain good wall apposition. The stent length should take into account the various turns of the parent artery (this is particularly important when placing a stent within the carotid siphon).

Periprocedure Medications Use of a stent requires dual antiplatelet therapy. This is typically achieved with aspirin and clopidogrel. It is our practice to begin the

dual antiplatelet regimen 5–7 days prior to the procedure with aspirin 325 mg daily and clopidogrel 75 mg daily. When this is not possible, loading doses of both medications (aspirin 650 mg and clopidogrel 600 mg) are administered immediately prior to the procedure. We routinely measure platelet inhibition assays to confirm adequate response to both medications. In cases in which a patient is unresponsive to clopidogrel (reported to occur in up to 50% of the population), we use ticagrelor (loading dose 180 mg, followed by 90 mg twice daily). Dual antiplatelet therapy is continued for 6 months after the procedure, at which time clopidogrel (or ticagrelor) is discontinued and aspirin is maintained indefinitely. In all cases of stent-assisted coiling, it is our practice to administer systemic heparinization. Full heparinization is confirmed by checking the activated coagulation time (ACT), with a therapeutic ACT of > 300 seconds.

Specific Technique and Key Steps 1. A 6 or 8 French (F) sheath is placed in the femoral artery. 2. A guide catheter is placed in the distal cervical segment of the appropriate vessel (e.g., internal carotid artery or vertebral artery) (Fig. 25.1-25.8, Video 25.1-25.8). 3. A three-dimensional angiogram is performed to assess aneurysm and parent vessel morphology (Fig. 25.1-25.8). 4. The parent vessel diameter is measured. The length of the stent is approximated by measuring the parent vessel. 5. Under roadmap guidance, the microcatheter (and intermediate catheter, if used) is advanced. 6. Jailing technique—One microcatheter is advanced in the parent vessel distal to the aneurysm neck for placement of the stent (Video 25.1-25.3). The stent is then advanced within the microcatheter but not yet deployed. A second microcatheter is advanced into the aneurysm. One or two loops of coil are deployed within the aneurysm. The stent is then deployed and coiling of the aneurysm is completed. 7. Traditional stent-assisted coiling—The microcatheter is advanced into the parent vessel distal to the aneurysm neck, and the stent is deployed. A microwire is advanced through the stent tines into the aneurysm, and the microcatheter is advanced into it. Coils are then deployed within the aneurysm. 8. Control injections are performed at the working angles to ensure aneurysm obliteration, stent patency, and adequate wall apposition. 9. Control injections are performed with full views of the intracranial vasculature to assess for delayed capillary filling, distal emboli, or vessel extravasation.

Device Selection In our practice, the following devices are routinely used for stentassisted coiling: • 6 or 8F sheath. • 6F guide catheter (Envoy XB, Codman Neuro; Benchmark, Penumbra; or 8F guide catheter, Neuron MAX, Penumbra). • Intermediate catheter (Distal Access Catheter [DAC], Stryker Neurovascular). • Stent and microcatheter selection (Table 25.1). • Microwire (Synchro 2, Synchro 10, Stryker). • Coils.

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V  Intracranial Aneurysms Table 25.1  Stent and microcatheter selection

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Stent

Manufacturer

Design

Diameter

Lengths

Microcatheter inner diameter (ID)

Neuroform

Stryker

Open

2.5–4.0 mm

10–30 mm

0.027 inch

Neuroform Atlas

Stryker

Hybrid

3.0–4.5 mm

15–30 mm

0.017 inch

Low-Profile Visualized Intraluminal Support Junior (LVIS Jr)

MicroVention

Closed

2.5–3.5 mm

13–34 mm

0.017 inch

Low-Profile Visualized Intraluminal Support (LVIS)

MicroVention

Closed

3.5–5.5 mm

12–33 mm

0.021 inch

Pearls

References

• Confirmation of platelet inhibition has become standard at many centers. Lack of adequate platelet inhibition has been associated with an increased frequency of thromboembolic complications. • In-stent thrombosis can be managed with aspiration or glycoprotein IIa/IIIb inhibitor infusion. We do not recommend mechanical thrombectomy because it can cause migration or movement of the stent. • When using the jailing technique, the deployed stent can serve as an anchor to help reduce redundancy in the coiling catheter. • When using the jailing technique, the deployment of one or two loops of coil within the aneurysm helps stabilize the microcatheter within the aneurysm during deployment of the stent.

[1] Higashida RT, Smith W, Gress D, et al. Intravascular stent and endovascular coil placement for a ruptured fusiform aneurysm of the basilar artery. Case report and review of the literature. J Neurosurg. 1997;87(6):944–949. [2] Mericle RA, Lanzino G, Wakhloo AK, Guterman LR, Hopkins LN. Stenting and secondary coiling of intracranial internal carotid artery aneurysm: Technical case report. Neurosurgery. 1998;43(5):1229–1234. [3] Hetts SW, Turk A, English JD, et al. Matrix and platinum science trial investigators. Stent-assisted coiling versus coiling alone in unruptured intracranial aneurysms in the matrix and platinum science trial: Safety, efficacy, and midterm outcomes. AJNR Am J Neuroradiol. 2014;35(4):698–705. [4] Feng MT, Wen Wl, Feng ZZ, et al. Endovascular embolization of intracranial aneurysms: To use stent(s) or not? Systemic review and meta-analysis. World Neurosurg. 2016;93:271–278. [5] Bodily KD, Cloft HJ, Anzino G, et al. Stent-assisted coiling in acutely ruptured intracranial aneurysms: A qualitative, systemic review of the literature. AJNR Am J Neuroradiol. 2011;32(7):1232–1236. [6] Linzey JR, Griauzde J, Guan Z, et al. Stent-assisted coiling of cerebrovascular aneurysms: Experience at a large tertiary center with a focus on predictors of recurrence. J Neurointerv Surg. 2017;9(11):1081–1085.

25  Stent-Assisted Coiling

Case Overview

CASE 25.1 Superior Hypophyseal Artery Aneurysm: Stent-Assisted Coiling Jailing Technique (Neuroform Atlas Stent)

• A 48-year-old female presented to the emergency department with acute double and blurry vision. Neurological examination was normal. She has a past medical history of hypertension, diabetes, and familial history of subarachnoid hemorrhage.

• Computed tomography (CT) was normal. • CT angiography demonstrated a left superior hypophyseal artery (SHA) aneurysm.

Fig 25.1a  CT angiography showing left wide-necked SHA aneurysm.

Fig 25.1b  Artist’s illustration of stent-assisted coiling of left SHA aneurysm (Jailing technique).

Fig 25.1c  Coiling microcatheter in the aneurysm.

Fig 25.1d  Stent microcatheter in the internal carotid artery.

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Fig 25.1e  Stent deployment (red arrows) coiling microcatheter jailed (blue arrow).

Fig 25.1f  Stent.

Fig 25.1g  Progressive coiling.

Fig 25.1h  Complete aneurysm obliteration.

Video 25.1  Stent-assisted coiling of an ICA aneurysm

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25  Stent-Assisted Coiling

Procedure • The patient underwent elective endovascular stent-assisted coiling of left SHA aneurysm. Patient was given aspirin 325 mg daily and clopidogrel 75 mg for 7 days prior to the intervention. The procedure was performed under general anesthesia and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.017-inch Excelsior XT-17 microcatheter (Stryker). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 21 mm Neuroform Atlas stent (Stryker). • Multiple intracranial coils • 6F AngioSeal percutaneous closure device.

This unruptured enlarging aneurysm presented with cranial nerve neuropathy and diplopia, the aneurysm’s neck is wide and endovascular coiling requires balloon- or stent-assisted tech-niques. A 6F catheter was navigated into the distal petrous internal carotid artery (ICA) segment. Jailing technique was used. Under road and magnification, a coiling microcatheter was advanced into the aneurysm, followed by a stenting microcatheter advanced into the ICA bifurcation. Few coil loops were deployed in the aneurysm. The stent is advanced and deployed across the aneurysm neck. The rest of the coils were inserted until the aneurysm was completely obliterated. Jailing technique permits microcatheter stabilization during coiling. The size of this patient’s intracranial ICA was 3.5 mm; therefore, a relatively small stent (Neuroform Atlas) was used.

Tips, Tricks & Complication Avoidance • In the last decade, several laser-cut or braided stents have been introduced such as Solitaire, Neuroform, Neuroform Atlas, Enterprise, Enterprise2, Leo, Leo baby, low profile visualized intraluminal support (LVIS), LVIS Jr, and Acclino stent. Neuroform Atlas (Stryker) stent is the successor to the Neuroform stent as the first approved for intracranial aneurysm treatment. It is intended for the treatment of aneurysm on a small parent vessel ranging from 2.5 to 4 mm. It can be delivered through standard coiling microcatheters down to an inner diameter of 0.0165-inch (Excelsior SL10 [Stryker], Headway DUO [Microvention]).

• European early multicenter postmarketing registry showed Neuroform Atlas stent placement was possible and accurately (because of minimal to no foreshortening) in all cases. There were no permanent morbidity or mortality with a periprocedural rate of 2.7% (one case) (J Neurointerv Surg. 2018). • Be familiar with the stent and its multiple markers to achieve an accurate deployment. • Multiple sizes of the stent include 3x (15, 21, 24) mm, 4x (21, 24) mm, 4.5x (21, 30) mm.

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Case Overview

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CASE 25.2 Anterior Communicating Artery Aneurysm: Stent-Assisted Coiling (LVIS Jr Stent)

• A 77-year-old male presented to the emergency department with transient altered mental status. Neurologically, the patient was awake, alert, oriented to person only. No motor or sensory deficits. No focal deficits. He had a past medical history of hypertension, atrial fibrillation, chronic leukemia, coronary artery diseases, and heart failure. The patient is currently taking aspirin and warfarin.

Further work-up revealed hyponatremia (Na 130) was the cause of his neurological symptoms. • Computed tomography (CT) was normal. • CT angiography demonstrated an anterior communicating artery (ACoA) aneurysm.

Fig 25.2a  3D CT angiogram demonstrating the ACoA aneurysm.

Fig 25.2b  Artist’s illustration of stent-assisted coiling of ACoA aneurysm with LVIS stent.

Fig 25.2c  ACoA aneurysm.

Fig 25.2d  Stent-delivering microcatheter in an A2 artery.

25  Stent-Assisted Coiling

Fig 25.2e  Coiling microcatheter in the aneurysm.

Fig 25.2f  Stent (arrows) positioning prior to deployment.

Fig 25.2g  Stent deployment (red arrows) and jailing of coiling microcatheter (white arrow).

Fig 25.2h  Coiling.

Fig 25.2i  Complete aneurysm obliteration.

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V  Intracranial Aneurysms Video 25.2  Stent-assisted coiling of an ACoA aneurysm

Procedure • The patient underwent elective endovascular stent-assisted coiling of ACoA aneurysm. Patient was started on 75 mg clopidogrel 7 days prior to his procedure and continued with his anticoagulation. No aspirin was given. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 7F dilator. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • Vitek Catheter (Cook Medical). • 0.021-inch Headway DUO microtheter (Microvention). • 0.017-inch Excelsior XT-17 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker) (2). • 2.5 x 23 mm low-profile visualized intraluminal support (LVIS) Jr stent (Microvention). • Multiple intracranial coils. • 8F AngioSeal percutaneous closure device.

This ACoA wide-neck aneurysm requires balloon or stent support to achieve proper and safe coiling treatment. Although the approach can be from any of the two anterior cerebral arteries (ACAs), the left ACA was chosen to accommodate the stent into the right A2 and left A1. A microcatheter was advanced into the right A2, a second microcatheter was advanced into the aneurysm. The stent was advanced and deployed. A small (2.5 x 23 mm) intracranial stent was used after proper measurements of the A1 and A2 vessels were obtained. Coils were advanced into the aneurysm until we obtained complete aneurysms obliteration. LVIS Jr has allowed treatment of intracranial aneurysms with parent vessels smaller than 2.5 mm with an acceptable safety profile.

Tips, Tricks & Complication Avoidance • The U.S. LVIS pivotal trial was a prospective, multicenter, single-arm interventional study conducted at 21 U.S. centers. The study enrolled 153 adults with WNAs of the anterior and posterior circulations. Successful aneurysm treatment with the LVIS system as evidenced by complete (100%) aneurysm occlusion was observed in 70.6% (108/153). Eight participants (5.2%, 8/153) had at least one primary safety event (stroke, death) (J Neurointerv Surg. 2018 [Epub ahead of print]). • A systematic review of nine studies that included 390 aneurysms treated showed a technical success rate of 96.8%. Failure of the

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stent to expand adequately was the main cause. Complete occlusion (Raymond-Roy 1) rate was seen in 84.6% at follow-up. Recanalization rate was 2.5% (J Neurointerv Surg. 2017;9(6):553–557). Overall complication rate was 6.5%. Thromboembolic complications were seen in 4.9%. • During deployment, the stent can be manipulated to protrude into the aneurysm neck to provide maximal neck coverage: the “shelf” technique. The shelf technique can be used for wide-necked bifurcation aneurysms and might obviate the need for complicated stent configurations.

25  Stent-Assisted Coiling

Case Overview

CASE 25.3 Anterior Communicating Artery Aneurysm: Stent-Assisted Coiling (Neuroform Atlas Stent)

• A 67-year-old female was admitted to the emergency department after cardiac arrest. After resuscitation and once the patient was hemodynamically stable, a magnetic resonance image (MRI) was obtained to rule out ischemia. After extubation and no sedation, the patient was neurologically intact. Patient had a history of

hypertension, atrial fibrillation, and familial history of subarachnoid hemorrhage. • MRI did not showed ischemia but demonstrated an anterior communicating artery (ACoA) aneurysm. • Computed tomography (CT) angiography demonstrated a widenecked ACoA aneurysm.

Fig 25.3a  CT angiography demonstrating a wide-necked ACoA aneurysm.

Fig 25.3b  3D reconstruction of the ACoA aneurysm.

Fig 25.3c  Artist’s illustration of stent-assisted coiling treatment of ACoA aneurysm (Atlas stent and bilateral approach).

Fig 25.3d  Bilateral femoral artery access.

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Fig 25.3e  Stent-delivering microcatheter advanced from left A1 to right A2.

Fig 25.3f  Coiling microcatheter accessing the aneurysm from the right A1.

Fig 25.3g  Jailing technique. After an initial coil loop (blue arrow) is positioned in the aneurysm, the stent (red arrows) is deployed.

Fig 25.3h  Coiling.

Fig 25.3i  Successful aneurysm obliteration.

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25  Stent-Assisted Coiling Video 25.3  Stent-assisted coiling of a complex ACoA aneurysm

Procedure • The patient underwent elective endovascular stent-assisted coiling of ACoA aneurysm. Patient was given 75 mg clopidogrel for 7 days prior to the intervention and remained on anticoagulation for her atrial fibrillation. No aspirin was given. The procedure was performed under general anesthesia and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Right femoral artery access. – Micropuncture kit. – 7F sheath. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 0.017-inch Excelsior XT-17 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple intracranial coils. • 8F AngioSeal percutaneous closure device.

This ACoA aneurysm in particular has a wide neck and incorporates both A2 branches. Simple coil or balloon-assisted coiling has a high risk of parent vessel occlusion; therefore, stentassisted coiling was chosen. Ideally, the stent should cover both A2 branches and to achieve so the stent needs to be deployed from the right A2 to the left A1. Bilateral femoral artery access was obtained, and two guide catheters were navigated into each internal carotid artery. The coiling microcatheter was advanced through the right guide catheter and the stenting microcatheter through the left guide catheter. Simultaneous catheter injections for road map was performed. First, the stenting microcatheter was advanced up to the distal right A2, followed by the right microcatheter into the aneurysm. Few coil loops were advanced into the aneurysm followed by stent deployment. The rest of the coils were advanced to complete aneurysm obliteration. The flexibility of the Neuroform Atlas stent permitted accurate and adequate deployment along the curved vessels.

• Left femoral artery access. – Micropuncture kit. – 6F sheath. • Envoy XB DA guide catheter (Codman). • 0.017-inch Excelsior XT-17 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • 3 x 21 mm Neuroform Atlas stent (Stryker). • 6F AngioSeal percutaneous closure device.

Tips, Tricks & Complication Avoidance • An advantage of Neuroform Atlas over other intracranial stents is that all stent sizes can be delivered through the smallest microcatheter (0.0165 inch). • Neuroform Atlas stent combines open- and closed-cell designs. The closed cell at the proximal end facilitates recrossing the stent for coiling and provides stable adherence to the vessel wall. • The stent cell size has been decreased compared with its predecessor (Neuroform) to reduce coil protrusion and to allow the use of smaller coils.

• Neuroform Atlas stent does not have a leading tip of the stent wire, reducing the risk of distal vessel perforation. This facilitates deployment in very tortuous vessels or before a sharp bend in which a leading tip could injure the vessel wall. • Relative disadvantages of Neuroform Atlas stent compared to LVIS Jr or Enterprise2 is the less visible, and resheathing of the device is not possible.

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Case Overview

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CASE 25.4 Recurrent Giant Posterior Communicating Artery Aneurysm: Stent-Assisted Coiling And Flow Diverter Reconstruction

• A 39-year-old male had a previously ruptured left posterior communicating artery (PCoA) aneurysm managed with microsurgical clip ligation and hematoma evacuation. Patient recovered completely with no neurological deficits. • Three years later, there was significant aneurysm recurrence treated with endovascular coiling.

• Four years later after the coiling procedure, he presented to the emergency department with severe headaches. • Computed tomography (CT) was normal. • CT angiography demonstrated significant recurrence of the previously clipped and coiled PCoA aneurysm.

Fig 25.4a  Initial CT showing diffuse subarachnoid hemorrhage and left temporal intraparenchymal hemorrhage.

Fig 25.4b  CT angiography showing recurrent PCoA aneurysm after initial clipping.

Fig 25.4c  CT angiography showing complete coil embolization of recurrent PCoA aneurysm.

Fig 25.4d  Artist’s illustration of stent-assisted coiling and flow diversion reconstruction of a large recurrent PCoA aneurysm. (Inset) Artist’s illustration close up of the LVIS Jr stent in the PCoA.

25  Stent-Assisted Coiling

Fig 25.4e  Bilateral femoral artery access.

Fig 25.4f  Anteroposterior and lateral angiography showing the large recurrent PCoA aneurysm. Observe the PCoA incorporated within the aneurysm (arrow).

Fig 25.4g  PCoA access with microcatheter.

Fig 25.4h  Flow diverter delivering microcatheter in the left middle cerebral artery.

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Fig 25.4i  LVIS Jr stent (arrows) deployed in the PCoA.

Fig 25.4j  Jailing technique. The coiling microcatheter (blue arrow) is within the aneurysm, then the flow diversion stent (red arrow) is deployed.

Fig 25.4k  Intra-aneurysmal flow stasis after flow diverter deployment.

Fig 25.4l  Coiling.

25  Stent-Assisted Coiling

Fig 25.4m  Immediate final result.

Fig 25.4n  1 year follow-up angiogram with complete aneurysms obliteration. PCoA is patent (arrow) but filling from posterior circulation. Patient remains asymptomatic.

Video 25.4  Stent-assisted coiling and flow diversion of a large recurrent complex PCoA aneurysm

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Procedure • The patient underwent elective endovascular stent-assisted coiling and flow diversion reconstruction of PCoA aneurysm. Patient was given 325 mg aspirin daily and 75 mg clopidogrel for 7 days prior to the intervention. The procedure was performed under general anesthesia and through bilateral femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Right femoral artery access. – Micropuncture kit. – 7F sheath. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • Navien 0.058 intermediate catheter (Medtronic). • 0.027-inch Marksman microcatheter (Medtronic). • 5 x 25 mm pipeline embolization device (Medtronic). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple intracranial coils. • 8F AngioSeal percutaneous closure device.

This is a complex large recurrent PCoA aneurysm. Patient had previous surgery and coil embolization. Permanent endovascular treatment requires flow diversion stenting. The PCoA arises from the aneurysm neck and could prevent from aneurysm thrombosis after flow diversion; therefore, dense aneurysm coiling is needed. To maintain patency of PCoA after coil occlusion of the aneurysm, a stent is used to preserve PCoA patent. A 0.0165-inch microcatheter is advanced into the PCoA, a second 0.017-inch microcatheter is advanced into the aneurysm, and a third 0.027inch catheter is advanced into the middle cerebral artery. A LVIS Jr stent is precisely placed at the PCoA, so the proximal end of the stent ends exactly at the PCoA ostium. A flow diverter is advanced and deployed from the internal carotid artery (ICA) terminus to the cavernous ICA. Last, multiple coils were advanced into the large aneurysm to obtain Raymond-Roy II obliteration.

• Left femoral artery access. – Micropuncture kit. – 6F sheath. • Envoy XB DA guide catheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker) (2). • 2.5 x 12 mm low-profile visualized intraluminal support LVIS Jr Stent (Microvention). • 6F AngioSeal percutaneous closure device.

Tips, Tricks & Complication Avoidance • Flow diversion has demonstrated to be a good alternative for the treatment of recurrent aneurysms previously coiled or clipped. • 15% of the ICA side branches (ophthalmic, PCoA, anterior choroidal arteries) covered by a flow diversion stent will occlude; however, patients remain asymptomatic (J Neurosurg. 2017;126(4):1064–1069). • There have been reports of aneurysm rupture after flow diversion treatment. This is most commonly seen in large and giant aneurysms. We strongly recommend the use of coils when treating large or

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giant aneurysms with flow diversion. About 20% of delayed ruptures occurred despite associated coiling. 75% of the ruptures occurs 1 month after flow diversion stent placement (Neuroradiology. 2016;58(2):171–177). Mechanisms of late aneurysm rupture include flow modifications after stent placement results in intra-aneurysmal pressure increments; intra-aneurysmal is a source of various proteases with high proteolytic activity that could participate in the degradation of the arterial wall and lead to aneurysm rupture.

25  Stent-Assisted Coiling

Case Overview

CASE 25.5 Middle Cerebral Artery Aneurysm: Stent-Assisted Coiling (Enterprise2 Stent)

• A 71-year-old female presented dizziness evaluation. The patient was neurologically intact. She had a past medical history of hypertension, diabetes, coronary artery diseases, and three cardiac stents. The patient is currently taking aspirin and clopidogrel.

• Computed tomography (CT) was normal. • CT angiography demonstrated left internal carotid artery (ICA) stenosis and left wide-necked middle cerebral artery (MCA) aneurysm.

Fig 25.5a  3D CT angiogram demonstrating the MCA aneurysm.

Fig 25.5b  Artist’s illustration of stent-assisted coiling of MCA aneurysm with Enterprise stent.

Fig 25.5c  Left MCA aneurysm.

Fig 25.5d  Stent delivering microcatheter in superior middle cerebral artery.

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Fig 25.5e  Coiling microcatheter.

Fig 25.5f  Stent deployment (red arrows) and jailing of coiling microcatheter (white arrow).

Fig 25.5g  Coiling.

Fig 25.5h  Complete aneurysm obliteration.

Video 25.5  Stent-assisted coiling of an MCA aneurysm

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25  Stent-Assisted Coiling

Procedure • The patient underwent elective endovascular stent-assisted coiling of MCA. Patient continued with her 325 mg aspirin daily and 75 mg clopidogrel. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activating clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.021-inch Headway DUO microcatheter (Microvention). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker) (2). • 4.5 x 22 mm closed-cell stent Enterprise2 (Codman). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This medium-sized wide-necked aneurysm needs treatment with a stent-assisted coiling technique. The tortuosity of the M2 branches requires a stent that conforms adequately without kinking or prolapsing into the aneurysm, the Enterprise2 stent is a good alternative. A 6F guide catheter is positioned at internal carotid artery. A 0.021-inch microcatheter is advanced into the superior M2 branch and a 0.0165-inch microcatheter is advanced into the aneurysm. The stent is deployed across the aneurysm neck and coils are inserted through the jailed microcatheter into the aneurysm until obtaining adequate coil packing. Enterprise2 is a closed-cell stent designed to expand and contract in vessel tortuosity and allows for deployment and recapture.

Tips, Tricks & Complication Avoidance • Entreprise2 stent has an enhanced closed-cell design that improves conformability and wall apposition while maintaining the benefits of a closed-cell design. The stent elongates on the outside radius and compresses on the inside radius of the bend. • Enterprise2 stent sizes include 4.5 x (14, 22, 28, 37) mm. Recommended parent vessel diameter is 2.5–4 mm.

• Early clinical experience with Enterprise2 stent demonstrated easy delivery, with partial or complete recapturing. When vascular anatomy showed curves with angles > 50°, it was regularly observed that the proximal stent markers were asymmetrically arranged along the vessel circumference without influence on the stent apposition (Clin Neuroradiol. 2018;28(2):201–207).

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Case Overview

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CASE 25.6 Recurrent Basilar Apex Aneurysm: Stent-Assisted Coiling (LVIS Stent)

• A 73-year-old female had history of ruptured basilar apex (BA) aneurysm treated with endovascular coil embolization. She recovered completely from the subarachnoid hemorrhage. She had past medical history of hypertension, coronary, and peripheral artery disease.

• One year follow-up diagnostic cerebral angiogram demonstrated significant aneurysm recurrence. The patient remained neurologically intact.

Fig 25.6a  Diagnostic cerebral angiogram demonstrating the BA aneurysm recurrence.

Fig 25.6b  Artist’s illustration of stent-assisted coiling treatment of recurrent BA aneurysm with LVIS stent.

Fig 25.6c  Stent delivering microcatheter in right posterior cerebral artery.

Fig 25.6d  Coiling microcatheter in BA aneurysm recurrence.

25  Stent-Assisted Coiling

Fig 25.6e  Coiling.

Fig 25.6f  Complete aneurysm obliteration.

Video 25.6  Stent-assisted coiling of a recurrent basilar apex aneurysm

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Procedure • The patient underwent elective endovascular stent-assisted coiling of BA aneurysm recurrence. Patient was given 325 mg aspirin daily and 75 mg clopidogrel for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Bilateral standard femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Excelsior XT-17 microcatheter (Stryker). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker) (2). • 3.5 x 23 mm low-profile visualized intraluminal support (LVIS) stent (Microvention). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This is recurrent BA aneurysm after initial treatment with coil embolization. The recurrent aneurysm has grown over to the right side of the BA in intimal relation with the right posterior cerebral artery (PCA). After obtaining access in the vertebral artery with a large guide catheter, two microcatheters are advanced, one into the right PCA and a second one in the aneurysm. The stent is deployed. The jailed coiling microcatheter in the aneurysm is maintained in the inferior third of the small aneurysm and coils are advanced.

Tips, Tricks & Complication Avoidance • The LVIS device is a self-expanding nickel titanium (nitinol) singlewire braid, closed-cell microstent. There are two types: LVIS and LVIS Jr. The LVIS stent, compatible with a 0.021-inch microcatheter, has a cell size of 1.0 mm and is recommended for a parent vessel size of 2–5 mm. The LVIS Jr stent, compatible with a 0.017-inch microcatheter, has a cell size of 1.5 mm and is intended for vessels sized 2–3 mm.

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Both stents can be fully reconstrained after deployment of up to 80% of its length. • Posterior circulation aneurysms have a high rate of recurrence after simple coiling. Stent-assisted coiling allows for more dense coil packing and reduces the risk of recurrence.

25  Stent-Assisted Coiling

Case Overview

CASE 25.7 Basilar Apex Aneurysm: Stent-Assisted Coiling “Y” LVIS Stent

• A 64-year-old female presented to the emergency department with the a 2-week history of the worst headache of her life. Neurologically, the patient was intact. She had a past medical history of hypertension, coronary artery diseases, and recent cardiac stent. The patient had been taking aspirin and clopidogrel.

• Computed tomography was normal. Lumbar puncture was positive for xanthochromia. • Diagnostic cerebral angiogram demonstrated a basilar apex (BA) aneurysm.

Fig 25.7a  3D cerebral angiogram reconstruction demonstrating the BA aneurysm recurrence.

Fig 25.7b  Artist’s illustration of stent-assisted coiling of BA aneurysm with “Y” stent technique.

Fig 25.7c  Stent-delivering microcatheter in left posterior cerebral artery.

Fig 25.7d  Coiling microcatheter in BA aneurysm.

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Fig 25.7e  Stent deployment and jailing of the coiling microcatheter.

Fig 25.7f  Stent-delivering microcatheter in right posterior cerebral artery and stent deployment.

Fig 25.7g  Successful “Y” stenting.

Fig 25.7h  Coiling through the jailed microcatheter.

Fig 25.7i  Complete aneurysm obliteration.

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25  Stent-Assisted Coiling Video 25.7  Y-configuration stent-assisted coiling of a basilar apex aneurysm

Procedure • The patient underwent elective endovascular stent-assisted coiling of BA aneurysm using the “Y” technique. Patient was given a bolus of 650 mg aspirin and 300 mg clopidogrel the day prior to the intervention. The procedure was performed under general anesthesia and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microtheter (Microvention). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker) (2). • 3.2 x 23 mm low-profile visualized intraluminal support (LVIS) Jr stent (2) (Microvention). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This symptomatic small BA aneurysm has a wide neck and is symmetrically situated between both posterior cerebral arteries (PCAs). Stents in both PCAs are necessary to adequately cover the aneurysm neck and prevent coils herniating into either PCA (“Y” stenting technique). After obtaining access in the vertebral artery, under road map and magnification, we found proper working views to visualize the aneurysm neck. A microcatheter is advanced into the left PCA and the stent loaded. A second microcatheter is advanced into the aneurysm and few coil loops are inserted. The first stent is deployed, jailing the coiling microcatheter. The stenting microcatheter is removed from the left PCA and advanced into the right PCA; the second stent is deployed. Once the aneurysm neck is covered by the two stents, we continued with aneurysm coiling until complete obliteration.

Tips, Tricks & Complication Avoidance • Patient selection for these endovascular complex approaches is key. Do not attempt “Y” stent placement when alternatives, such as microsurgical clipping, use of flow diverter, or use of neck reconstruction device (PulseRider, Barrel), can be performed with less likelihood of placing the patient at risk. • The “shelf” technique is a feasible and safe alternative to Y-stenting. The compliant and flexible closed-cell design of braided stents such as the LVIS Jr allows for the creation of a “shelf” across the aneurysm neck sufficient to prevent coil prolapse.

• Because of the amount of metal within the parent vessel, thromboembolism and artery occlusion could be a problem. Adequate dual-antiplatelet therapy and intraprocedural anticoagulation is imperative. After completing the procedure, perform several angiography runs to look for slow flow within the parent vessel or distal branch occlusion. We strongly suggest to not reverse anticoagulation at the end of the intervention.

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Case Overview

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CASE 25.8 Recurrent Basilar Apex Aneurysm: Stent-Assisted Coiling (Enterprise2 Stent)

• A 64-year-old female presented to the emergency department with a 2-week history of severe headaches. Neurologically, the patient was intact. She had a past medical history of hypertension, coronary artery diseases, and intracranial aneurysm.

• Patient had a ruptured basilar apex (BA) aneurysm treated with stent-assisted coiling 2 years prior to her current presentation. She is currently taking aspirin. • Current computed tomography was normal; however, lumbar puncture was positive for xanthochromia. • Diagnostic cerebral angiogram demonstrated a BA aneurysm.

Fig 25.8a  3D cerebral angiogram reconstruction demonstrating the BA aneurysm recurrence.

Fig 25.8b  Artist’s illustration of stent-assisted coiling treatment with Enterprise stent of recurrent BA aneurysm previously treated with stent/coil.

Fig 25.8c  Stent delivering microcatheter in left posterior cerebral artery through the previous stent.

Fig 25.8d  Coiling microcatheter in BA aneurysm recurrence.

25  Stent-Assisted Coiling

Fig 25.8e  Stent deployment and jailing of the coiling microcatheter.

Fig 25.8f  Coiling.

Fig 25.8g  Complete aneurysm obliteration.

Video 25.8  Y-configuration stent-assisted coiling of a recurrent basilar apex aneurysm

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Procedure • The patient underwent endovascular stent-assisted coiling of BA aneurysm recurrence. Patient continued with aspirin. 75 mg of clopidogrel was added to the antiplatelet regimen prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch Headway DUO microtheter (Microvention). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microwire (Stryker) (2). • 4 x 23 mm closed-cell stent Enterprise2 (Codman). • Multiple intracranial coils. • 6F AngioSeal percutaneous closure device.

This patient had a ruptured BA aneurysm treated with stentassisted coiling and now presents with symptomatic aneurysm recurrence. Retreatment with simple coil or balloon-assisted coiling most likely will result in recurrence. “Y”-stenting is an alternative to achieve dense coil packing and reduce the risk of recurrence. The stent used in the initial stent-assisted coiling was a low-profile visualized intraluminal support (LVIS) stent (Microvention). Once access at the vertebral artery was obtained and under road map and magnification, a microcatheter was advanced through the stent and into the left posterior cerebral artery (PCA) using a microwire with a “J” configuration tip. A second microcatheter was advanced into the aneurysm. A closed-cell stent (Enterprise2) was deployed at the left PCA and basilar artery. Through the jailed microcatheter already placed in the aneurysm, multiple coils were inserted to obliterate the aneurysm recurrence.

Tips, Tricks & Complication Avoidance • Kissing-Y stenting in wide-necked bifurcation aneurysms leads to vascular angular remodeling of both affected branches. The resulting straightening of the bifurcation angle could contribute to preventing aneurysmal recurrence (J Neurointerv Surg. 2017;9(12):1233–1237). • In basilar apex aneurysms, computational fluid dynamic analysis showed that angular remodeling led to significant narrowing of the

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wall shear stress (WSS) interpeak at the apex, redirecting high WSS away from the neck transition zone with native vessel toward the inert coil mass. • Use a “J” microwire configuration while crossing an LVIS stent to decrease the likelihood of going through different stent spaces or tines.

26  Flow Diversion Treatment of Intracranial Aneurysms Gary B. Rajah, Giuseppe Lanzino, and Leonardo Rangel-Castilla

General Description

Perioperative Medications

The flow diverter (FD) is a relatively new development in endovascular neurosurgery. There are several FDs currently available, each with its own nuances. Device selection is largely based on operator preference and experience. Devices include the pipeline embolization device (PED, Medtronic), Surpass (Stryker), the flow-redirection endoluminal device (FRED, MicroVention), Silk (Balt Extrusion), and the p64 (Phenox). Each device has its own specific characteristics with different lengths, filament size and number, design, and deployment. The most commonly used FD is the PED. The PED was initially utilized in North America by Fiorella et al. in 2008.1 The FDA-approved indication for use included large, wide-necked aneurysms from the petrous portion of the internal carotid artery (ICA) to the paraclinoid ICA region. Many studies boast an 80%–90% overall aneurysm obliteration rate. In the Buenos Aires experience, Kallmes et al.2 reported obliteration in 90% of intracranial aneurysms (IAs) at the 1-year follow-up and in 100% of IAs at 8 years. Flow diversion is now being utilized in some studies for small IAs as an alternative treatment to stent coiling or clipping. The PED is a braided stent composed of 48 cobalt/chrome and platinum/tungsten wires providing 25%–35% metal coverage, depending on the size of the device. The device is available in diameters of 2.5–5 mm and lengths of 10–35 mm. When opened, the device is 0.25 mm larger than the stated diameter. Flow diversion works by mechanical redirection of blood flow, which allows for intra-aneurysmal stagnation of blood, eventually leading to vessel reconstruction via endothelialization along the device. Of note, perforators are typically spared during FD treatment if they are end vessels; however, care should be taken when deciding which aneurysms to treat because essential arterial perforators can be occluded. For long-segment vessel pathology, PEDs can be placed in tandem.

Given the large amount of metal coverage, a course of dual antiplatelet therapy is prescribed before the FD procedure and systemic heparinization is administered during FD deployment. Aspirin (325 mg daily) and clopidogrel (75 mg daily) are given for at least 5 days prior to device placement. Then, before the procedure, therapeutic platelet function testing (VerifyNow, Accriva Diagnostics) is conducted to monitor the presence and effectiveness of the antiplatelet medications. If the patient is a clopidogrel hypo- or nonresponder, ticagrelor (90 mg twice daily) can be used instead. If the patient was not started on dual antiplatelet therapy before the procedure, we administer abciximab (a glycoprotein IIb/IIIa platelet aggregation inhibitor) immediately after the placement of the first PED. Then, we administer 450 mg of clopidogrel and 325 mg of aspirin after the procedure. Clopidogrel (75 mg daily) or ticagrelor (90 mg twice daily) is maintained for at least 6 months. The patient remains on aspirin for life.

Indications The PED is FDA-approved “for the endovascular treatment of adults (age 22 years and above) with large or giant wide-necked IAs in the ICA from the petrous to the superior hypophyseal segments.” Off-label uses include aneurysms of the middle cerebral artery, anterior cerebral artery, anterior communicating artery, and those of the posterior circulation. The PED has been used in ruptured aneurysms and blister aneurysms with good results.

Neuroendovascular Anatomy Although some FDs are more flexible and trackable than others, these devices contain a large amount of metal. Thus, they must be advanced (“pushed”) via a pusher wire through a microcatheter to the location of interest. The degree of tortuosity from the groin (femoral artery) to the neck (carotid artery) must be assessed, and the proper guide catheters selected. Furthermore, tortuosity of the neck vessels and the carotid siphon can make it very difficult to push some devices. Perforators must also be assessed. Midbasilar device placement can have disastrous consequences because of the many pontine perforators; however, typically, the benefit of treating a midbasilar IA will outweigh the risk. Vessels such as the ophthalmic and anterior choroidal arteries should be preserved and a device landing zone selected with this in mind. Vessels leaving the apex of the aneurysm can decrease the effectiveness of the FD treatment. Rangel-Castilla et al.3 reported a 15.8% occlusion rate for side-branch vessels covered with PED for aneurysm treatment. At the long-term follow-up, no occlusions were symptomatic.

Specific Technique and Key Steps 1. After a femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is placed over a curved wire/diagnostic catheter (e.g., 0.035-inch angled Glidewire, Terumo), and the system is advanced into the aorta under fluoroscopic guidance (Fig. 26.1-26.10, Video 26.1-26.10). 2. The guide catheter should be placed in the extracranial vessel (ICA, common carotid artery, or vertebral artery) of choice utilizing roadmap navigation. 3. The intermediate catheter (Sofia catheter, MicroVention) or distal access catheter (DAC, Cook) is connected to the heparinized flush and introduced through the guide catheter. The use of an intermediate catheter is recommended in cases of moderate-tosevere vessel tortuosity (Fig. 26.5, 26.6, Video 26.5, 26.6). 4. A 0.027-inch microcatheter (e.g., Marksman, Medtronic; Headway 27, MicroVention; or Excelsior XT-27, Stryker Neurovascular) is connected to a heparinized flush and introduced through the intermediate or guide catheter. 5. The correct working views of the aneurysm are identified on magnified anteroposterior and lateral fluoroscopy. 6. Under roadmap guidance, the intermediate catheter is navigated and placed 1–2 cm proximal to the aneurysm neck. 7. The microwire and microcatheter are advanced past the aneurysm neck. A distal purchase of 2 cm is recommended and is often necessary because of the stiff delivery system of the PED and its propensity to move the catheter out of position when navigating the device (Video 26.1-26.10). (Note: for large aneurysms, the microwire and/or microcatheter may loop several times within the aneurysm before finding the distal ostium. Sometimes, a balloon in the distal vessel can assist with purchase for later straightening of the system (Fig. 26.1, Video 26.1).) 8. Sizing is important because longer devices can twist during deployment, but if compacted, shorter devices will result in incomplete coverage of the aneurysm neck. The device that is selected is typically 1 mm wider than the proximal diameter of the parent vessel with at least 5 mm on either side of the aneurysm neck, depending on whether the device will need to incorporate a bend. If placing multiple devices in tandem, ensure a 30%–50% overlap to prevent endoleak or unwanted loss of access. Packing larger devices into small parent vessels does not automatically

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9.

10.

11.

12.

13.

14.

15.

16.

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increase the metal coverage of the aneurysm neck. Incorrectly sized devices are likely to migrate and cause complications. The landing zone must be carefully selected at least 1 cm distal to the aneurysm neck to ensure the FD does not prolapse into the aneurysm. The FD is loaded into the 0.027-inch microcatheter. The plastic sheath that comes with the device should be back-flushed prior to pushing the device. The FD is advanced until the tip of the delivery system is aligned with the microcatheter tip, and the catheter and PED are pulled back as a unit until the distal PED is in the desired zone (Video 26.126.10). The device is deployed by first retracting the microcatheter while keeping the PED in place. The PED is then further deployed by pushing on the delivery wire and retracting the microcatheter (Video 26.1-26.10). During deployment, the FD should not be stretched. Aim for the shape of a wine glass. If the device appears stretched, push the microcatheter and device (“load the system”) and try compacting the device via the pusher wire. The FD is unsheathed via gentle retraction of the microcatheter with varying amounts of pushing on the pusher wire (Video 26.126.10). Some operators will push the device through curves for better apposition and compress it near the neck. Bear in mind, the more the device is manipulated, the greater the chance that it will twist, which can be difficult to correct; however, swaying the device to and fro can sometimes fix unwanted twisting. Once the FD has reached the point where it cannot be resheathed, you are committed to its deployment; prior to this, the device can be recaptured and redeployed. After the device has been successfully deployed, a test run can be performed to ensure good approximation and some intraaneurysmal flow stagnation (Video 26.1-26.10). If the operator is satisfied, the microcatheter is brought through the stent to retrieve the pusher wire. The pusher wire and microcatheter must be removed carefully to avoid stent migration. If the lesion requires tandem device placement, care should be taken to avoid losing device access by pushing the next device and repeating the above steps. Final runs are obtained. Some contrast stagnation (indicating that flow is being diverted) within the aneurysm is usually noted. Ensure good device apposition, otherwise balloon angioplasty may be needed.

Device Selection In our practice, the following are common set-ups and devices used for FD placement. • 8F or 6F sheath. • 8F guide catheter (90 cm Neuron MAX, Penumbra) or 6F guide catheter (Envoy XB DA, Codman Neuro). • Intermediate catheter (Navien, Medtronic), Sofia or Phenom (Medtronic).

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• 0.027-inch microcatheter (Marksman, Headway 27, or Excelsior XT27). • 0.014-inch Synchro 2 standard wire (Stryker). • FD. • Continuous heparinized flush.

Pearls • In-stent thrombosis can occur and should be managed like any acute stroke with diagnostic angiography followed by either thrombectomy or glycoprotein IIb/IIIa inhibitor infusion. • A stretched or constrained device can be opened within the intermediate catheter and then deployed as a last resort. • Losing access to the device within a large aneurysm can be disastrous because the device can migrate or no longer align with the proximal vessel. Transcirculation maneuvers can be utilized to regain access by way of snaring of a microwire, buddy wires, or the FD and removal. Last resort options include balloon test occlusion and vessel sacrifice. • FDs have been used off-label for cases of failed stent-coil aneurysm treatment with good results (Fig. 26.7-26.10, Video 26.7-26.10). • Large aneurysms in eloquent locations such as the midbasilar artery may benefit from heparinization in the postprocedure period to prevent massive thrombosis and perforator infarct (Fig. 26.10, Video 26.10). • Large aneurysms can become more symptomatic following device placement. As the lesion swells during thrombosis, pain/symptoms can be treated with steroids. Although the risk is low, late rupture has been observed as a result of clot autolysis. • Deploying the device in a small diameter landing zone under tension can lead to foreshortening and prolapse of the device. Deploying the device within a large diameter landing zone can lead to less metal coverage distally, requiring two devices. • The first-generation PED could not be resheathed and more than one device was often necessary to cover the aneurysm neck. The secondgeneration PED, Pipeline Flex (Medtronic), can be resheathed and reimplanted in the proper position. This improvement in the delivery system has significantly decreased the need for multiple devices. • A PED can foreshorten and prolapse into the aneurysm. Maintaining the position of the microcatheter distal to the aneurysm is critical because finding the lumen of a deployed device can be quite difficult once access is lost.

References [1] Fiorella D, Woo HH, Albuquerque FC, Nelson PK. Definitive reconstruction of circumferential, fusiform intracranial aneurysms with the pipeline embolization device. Neurosurgery. 2008;62(5):1115–1120. [2] Kallmes DF, Brinjikji W, Cekirge S, et al. Safety and efficacy of the pipeline embolization device for the treatment of intracranial aneurysms: A pooled analysis of 3 large studies. J Neurosurg. 2017;127(4):775–780. [3] Rangel-Castilla L, Munich SA, Jaleel N, et al. Patency of anterior circulation branch vessel after pipeline embolization: Longer-term results from 82 aneurysms cases. J Neurosurg. 2017;126(4):1064–1069.

26  Flow Diversion Treatment of Intracranial Aneurysms

Case Overview

CASE 26.1 Cervical Internal Carotid Artery Aneurysm: Flow Diversion

• A 49-year-old female presented with progressive pulsatile mass on the left anterior neck. She also described occasional tingling and numbness on the right upper and lower extremities. She denies any neck trauma; however, she remembers sudden left neck pain a few months prior to her current presentation. Her neurological examination was normal. She had a past medical history of hypertension, coronary artery

diseases, and recent cardiac stent. The patient has been taking aspirin and clopidogrel. • Computed tomography (CT) and magnetic resonance angiogram (MRA) demonstrated a large cervical internal carotid artery (ICA) aneurysm.

Fig 26.1a  CT angiogram and MRA demonstrating the large cervical ICA aneurysm with severe narrowing of the parent vessel.

Fig 26.1b  Artist’s illustration of PED embolization treatment of cervical ICA aneurysm.

Fig 26.1c  Cervical ICA dissecting aneurysm.

Fig 26.1d  After obtaining distal access in the ICA, balloon angioplasty is performed to correct the arterial dissection and stenosis.

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Fig 26.1e  Flow diversion stent deployment.

Fig 26.1f  Further flow diversion stent deployment.

Fig 26.1g  Aneurysm flow stasis after stent deployment.

Video 26.1  Flow diversion stenting for cervical ICA aneurysm

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Procedure • The patient underwent elective endovascular treatment of her cervical ICA with flow diversion stenting. Patient was given 325 mg aspirin and 75 mg clopidrogel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F dilator. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch exchange length (300 cm) Synchro 2 microwire (Stryker). • 4 x 15 mm HyperForm occlusion balloon (Medtronic). • 5 x 20 mm Pipeline Embolization Device (PED) mm Flex (Medtronic). • 8F AngioSeal percutaneous closure device.

This large cervical ICA aneurysm or pseudoaneurysm is probably the result of an initial ICA dissection. Endovascular goals include angioplasty of the dissection/stenosis and stent reconstruction. There is no carotid stent that could accommodate to small caliber (3.5) of the ICA. Flow diversion stent (pipeline) is a good alternative for stent artery reconstruction and aneurysm treatment. A 4 x 15 mm balloon is advanced into the ICA and balloon angioplasty of the ICA stenosis/dissection segment is performed. Over the exchange length 0.014-inch microwire, the balloon is exchanged for the 0.027-inch microcatheter. A 5 x 20 mm PED is advanced and deployed across the aneurysm neck. A device significantly larger in diameter than the parent artery was used to expand the vessel, reduce the stenosis, and create flow diversion on the aneurysm. A pipeline stent conformed well to the artery tortuosity without altering the anatomy, whereas a carotid stent could have strengthened and kinked the vessel.

Tips, Tricks & Complication Avoidance • Flow diversion stenting with PED is an adequate alternative for the management of high cervical and skull base dissections (Oper Neurosurg (Hagerstown) 2018 [Epub ahead of print]). • We suggest using a PED larger than the diameter of the extracranial vessel to reduce the risk of significant stent foreshortening and the need of a second PED.

• PED does not have enough radial force to treat extracranial vessel dissection or stenosis; therefore, we recommend balloon angioplasty prior to PED deployment. • Flow diversion stent (PED, Surpass) are adequate alternatives to carotid stents (Wallstent, Xact) in tortuous extracranial vessels. They are flexible and conform to vessel characteristics without the risk of vessel deformity resulting in straightening and kinking.

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Case Overview

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CASE 26.2 Internal Carotid Artery Cave Aneurysm: Flow Diversion

• A 51-year-old female was found to have multiple intracranial aneurysms during work-up for migraines. She has a past medical history of chronic headaches, migraines and familial history of subarachnoid hemorrhage (SAH). Three previous aneurysms have

been treated with endovascular coiling. Her neurological exam is normal. • Computed tomography (CT) angiogram demonstrated a mediumsized right internal carotid artery (ICA) wide-necked aneurysm.

Fig 26.2a  CT angiography showing the cave ICA aneurysm.

Fig 26.2b  Artist’s illustration of PED embolization cervical ICA cave aneurysm.

Fig 26.2c  Obtaining distal access.

Fig 26.2d  Flow diversion stent deployment. Notice multiple coils from previous aneurysms.

26  Flow Diversion Treatment of Intracranial Aneurysms

Fig 26.2e  Final angiography after flow diversion stent deployment demonstrating excellent wall apposition and aneurysm flow stasis (arrow).

Video 26.2  Flow diversion stenting for paraclinoid ICA aneurysm

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Procedure • The patient underwent elective endovascular treatment of her ICA cave aneurysm with flow diversion stenting. Patient was given 325 mg aspirin and 75 mg clopidogrel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 20 mm Pipeline Embolization Device (PED) flex (Medtronic). • 6F AngioSeal percutaneous closure device.

Currently, the majority of cavernous and paraclinoid ICA aneurysms are treated with flow diversion. This patient with multiple intracranial aneurysms treated endovascularly still has a cave ICA aneurysm that requires treatment. A 6F guide catheter is positioned at the petrous ICA. Under roadmap and navigation, a 0.027-inch microcatheter over a microwire is advanced into the middle cerebral artery. The microwire is exchanged for the PED. The PED is advanced until the tip of the delivery system is aligned with the microcatheter tip, and the catheter and PED are pulled back as a unit until the distal PED is in the desired location. We typically use the ICA bifurcation as the landing zone. The PED is deployed by retracting the microcatheter (unsheathing) while keeping the PED in place. By unsheathing the PED, it will create a “cigar” shape while it is still attached to the distal coil. Progressively continue unsheathing the PED until the end of the device fully expands and deploys. The ICA and the carotid syphon had no tortuosity and a simple 6F guide catheter and microcatheter were sufficient for adequate and accurate placement of the PED.

Tips, Tricks & Complication Avoidance • Even though cavernous ICA aneurysms are usually managed conservatively because of the minuscule risk of SAH. Cave ICA aneurysms carry the risk of SAH because they are anatomically located within the subarachnoid space. • Pipeline Flex (Pipeline, 2nd generation) has a great advantage over the first-generation PED. It can be resheathed in up to 75% of unsheathed stent. Also, compared to the first PED, Pipeline Flex will always open after unsheathing without the need for additional maneuvers (e.g., device rotation). If the “cigar” shape is still maintained during stent

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deployment, the neurosurgeon should not be concerned, as the stent will ultimately open. • In patients with minimal-to-no cervical ICA or carotid syphon tortuosity, a simple 6F guide catheter with a soft distal end (Envoy XB DA [Codman] or Benchmark [Penumbra]) advanced at the petrous ICA offers sufficient support for microcatheter intracranial navigation. There is no need for intermediate catheter. Adding an intermediate catheter could increase the risk of thromboembolism complications.

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Case Overview

CASE 26.3 Posterior Communicating Artery Aneurysm: Flow Diversion

• A 46-year-old female was found to have multiple intracranial aneurysms during work-up for migraine. A previous aneurysm was treated with microsurgical clip ligation. Her neurological exam was normal. She has a history of familial subarachnoid hemorrhage.

• A posterior communicating artery (PCoA) aneurysm has grown on follow-up imaging.

Fig 26.3a  Enlarging PCoA aneurysm.

Fig 26.3b  Artist’s illustration of PED embolization of PCoA aneurysm.

Fig 26.3c  Microcatheter advanced in middle cerebral artery.

Fig 26.3d  Flow diversion stent prior to deployment.

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Fig 26.3e  Distal segment of stent deployed.

Fig 26.3f  Further stent unsheathing but not expanded requiring a push maneuver (loading) against the inner wall of the curve.

Fig 26.3g  Further stent deployment.

Fig 26.3h  After complete stent deployment, the device is pushed against the inner artery wall with the delivering microcatheter (arrow) to obtain adequate wall apposition.

Fig 26.3i  Final angiography run demonstrating adequate stent deployment.

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26  Flow Diversion Treatment of Intracranial Aneurysms Video 26.3  Flow diversion stenting for PCoA aneurysm

Procedure • The patient underwent elective endovascular treatment of her PCoA aneurysm with flow diversion stenting. Patient was given 325 mg aspirin and 75 mg clopidogrel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • 3.25 x 25 mm Pipeline Embolization Device (PED) Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

This is a growing PCoA aneurysm in a young patient with personal and familial risk factors for aneurysm rupture. There is no large PCoA or fetal PCoA associated with the aneurysm and flow diversion is an adequate permanent treatment option. After obtaining adequate internal carotid (ICA) artery access with a 6F guide catheter, a 0.027-inch microcatheter is advanced intracranially. The PED stent is advanced and positioned at the ICA bifurcation. The device is unsheathed and the distal aspect of the PED is released. The remainder of the stent can be deployed by pushing the PED wire and retracting the microcatheter. When deploying the device around a curve, it is often necessary to push the PED until it sits along the far wall of the curve, only to then pull the microcatheter back to ensure that it sits along the proximal wall. Once the stent is deployed, the delivery wire is removed by advancing the microcatheter through the deployed stent until it captures the tip of the delivery system.

Tips, Tricks & Complication Avoidance • Before treating a PCoA aneurysm with flow diversion stenting, look for the presence of a large PCoA or fetal PCoA associated with the aneurysm neck, as there have been reports of incomplete aneurysm obliteration. Consider other alternatives including microsurgery, stent-assisted coiling, or intrasaccular flow diversion. • Deploy the stent slowly and deliberately, making sure that the device is apposing the arterial wall as it is unsheathed. Deploying it too

quickly can result in inadequate apposition or alternating segments of expanded and unexpanded stent. • An unexpanded stent can result in a mechanical flow obstruction and must be opened rapidly. This may require additional maneuvers with the delivering wire or microcatheter, and/or balloon angioplasty.

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CASE 26.4 Simultaneous Treatment of ICA Stenosis and PCoA Aneurysm: Flow Diversion

• A 70-year-old female with history of chronic headaches and migraines was found to have multiple intracranial aneurysms treated with endovascular techniques. Magnetic resonance angiography (MRA) follow-up at 3 years demonstrated a de novo formation of a posterior communicating artery (PCoA) aneurysm. She has a past medical his-

tory of hypertension, coronary artery disease, and a familial history of aneurysmal subarachnoid hemorrhage. Her neurological exam was normal. Patient current medications included aspirin and clopidogrel. • MRA demonstrated left PCoA aneurysm and left cervical internal carotid artery (ICA) stenosis.

Fig 26.4a  MRA showing the left PCoA aneurysm.

Fig 26.4b  MRA showing the left PCoA aneurysm.

Fig 26.4c  Artist’s illustration of carotid stenting of ICA stenosis and PED embolization of PCoA aneurysm.

Fig 26.4d  Left carotid angioplasty of ICA stenosis.

26  Flow Diversion Treatment of Intracranial Aneurysms

Fig 26.4e  Guide catheter through stent (arrow) to obtain further distal access.

Fig 26.4f  Left PCoA aneurysm. Obtaining ICA measurements.

Fig 26.4g  Unsheathing distal segment of PED. Stent has not opened.

Fig 26.4h  Further PED unsheathing. Stent has opened, except for the very distal segment (arrow).

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Fig 26.4i  Stent completely deployed. Distal segment opened with catheter manipulation while recapturing the delivering wire.

Fig 26.4j  Intra-aneurysmal flow stasis after stent deployment.

Video 26.4  Simultaneous carotid artery stenting and PCoA aneurysm treatment

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Procedure • The patient underwent elective endovascular treatment of her left PCoA aneurysm and left ICA stenosis with flow diversion and carotid angioplasty and stenting. The patient continued her dual-antiplatelet regimen. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Envoy XB guide catheter (Codman). • Emboshield NAV6 distal filter (Abbott Vascular). • Carotid Wallstent 8 x 21 mm (Boston Scientific). • Noncompliant Aviator balloon 3.5 x 30 mm (Abbott). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • 5 x 30 mm Pipeline Embolization Device (PED) Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

De novo aneurysm formation is relatively rare; however, it is concerning and treatment is advised. This patient has concomitant ipsilateral asymptomatic ICA stenosis. To have adequate endovascular intracranial access, the ICA stenosis should be treated. During the same procedure, carotid artery stenting/angioplasty and flow diversion for PCoA aneurysm were performed. After the carotid angioplasty and stenting was done, the 6F guide catheter was advanced thought the stent into the petrous ICA. Under road map and navigation, a 0.027-inch microcatheter was advanced into the ICA bifurcation. The PED was exchanged for the microwire and deployed at the landing zone (ICA bifurcation). The distal aspect of the PED was released but did not open, we continued unsheathing and pushing the device. The entire device was deployed and opened, except for the distal segment. The microcatheter was advanced up to the tip of the delivery wire, and by doing this the distal segment of the stent opened.

Tips, Tricks & Complication Avoidance • Initial problems with first-generation PED was the inability of recapture and stent not able to fully expand. This is rarely seen now with PED Flex. • When deploying the device around the carotid syphon, the system could move over to the inner aspect of the curve. This is corrected by pushing the wire and “loading” the system, advancing the catheter over the wire. If possible, the delivery system should always be kept along the center axis of the artery. • The delivery wire is then removed by advancing the microcatheter through the stent until it captures the tip of the delivery wire. The delivery wire is removed leaving the microcatheter in place, in case of the need for a second device. Maneuvering the microcatheter through

the deployed device apposes further the stent against the vessel wall and helps expanding segments of the stent that did not expand initially. • Angiogram is obtained to assess device and intra-aneurysmal flow stasis. Unsubtracted views give the best visualization of the PED, which allows the interventionist to best determine whether the device is adequately positioned, fully expanded, and well apposed to the arterial wall. • Computed tomography angiography with 3D reconstruction can be obtained when there is doubt of adequate wall apposition. The majority of neuroangiography suites has the capacity for this intraoperatively.

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Case Overview

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CASE 26.5 Ophthalmic Artery Aneurysm— Difficult Access due to Tortuous Cervical ICA: Flow Diversion

• A 75-year-old female was found to have an ophthalmic aneurysm during work-up for headaches. She was treated conservatively. On a 2-year follow-up magnetic resonance angiogram (MRA), there was

evidence of aneurysm growth. Her neurological exam was normal. Patient had a history of diabetes and hypertension. • MRA demonstrated a 6-mm ophthalmic artery (OphA) aneurysm.

Fig 26.5a  Ophthalmic artery aneurysm.

Fig 26.5b  Artist’s illustration of PED embolization of ophthalmic artery aneurysm with a tortuous carotid artery.

Fig 26.5c  Distal access with microcatheter into the left MCA obtained.

Fig 26.5d  Initial flow diverter on position for delivery (arrow).

26  Flow Diversion Treatment of Intracranial Aneurysms

Fig 26.5e  Stent foreshortening (arrow) resulted in inadequate aneurysm covering.

Fig 26.5f  Guide catheter (red arrow) repositioned for better distal access. An extra wire (V-18) was used for better guide support.

Fig 26.5g  Surgical instrument was used to advance the flow diversion stent.

Fig 26.5h  Second flow diversion device advanced past the aneurysm to prevent foreshortening.

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Fig 26.5i  Adequate aneurysm coverage with aneurysm flow stasis.

Video 26.5  Flow diversion stenting for PCoA aneurysm and tortuous carotid artery

Procedure • •The patient underwent elective endovascular treatment of growing ophthalmic artery aneurysm. Patient was given 325 mg aspirin and 75 mg clopidogrel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • Simmons 2 guide catheter. • 0.035-inch Glidewire exchange length. • Benchmark 071 guide catheter (Penumbra). • Vitek catheter (Cook Medical). • 0.018-inch V-18 Control Wire (Boston Scientific). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker) • 3.5 x 30 mm Pipeline Embolization Device (PED) Flex (Medtronic) • 3.75 x 14 mm Pipeline Embolization Device Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

This patient had an enlarging OphA aneurysm and treatment was recommended. A 6F guide catheter was attempted to navigate into the internal carotid artery (ICA); however, it was not possible because of severe vessel tortuosity. The guide catheter stayed at the common carotid artery. Under road map and magnification, a 0.027-inch microcatheter over a 0.014-inch microwire was advanced into the ICA terminus, distal to the OphA. The microwire was exchanged for the PED stent. There was significant resistance while advancing the device. The device was delivered and deployed; however, it did not cover the distal segment of the aneurysm. We tried to advance the microcatheter into the middle cerebral artery (MCA) but it created significant resistance and pushback of the guide catheter. For more support, a 0.018-inch wire (V-18) was introduced in the guide catheter, parallel to the microcatheter, allowing us to advance the guide catheter further distal to the ICA. While maintaining the V-18 in place, the microcatheter was advanced into the MCA. A second PED stent was deployed. Because we obtained further distal access into MCA, the device was deployed more distally, covering the aneurysm adequately.

Tips, Tricks & Complication Avoidance • Adequate catheter support is paramount and should be optimized prior to PED deployment. If the cervical ICA and carotid syphon have moderate-to-severe tortuosity, we strongly suggest using an intermediate catheter (distal access catheter [DAC], Sofia intermediate catheter) for better microcatheter stability. Use a large guide catheter (Neuron MAX, Asahi Fubuki) that easily accommodates an intermediate catheter and still has space for contrast injections.

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Creating a “triaxial system” may take additional steps, but it will save several steps and avoid potential complications later in the procedure if difficulties are encountered. • Occasionally, PED can foreshorten and prolapse into the aneurysm. Maintaining the position of the microcatheter distal to the aneurysm is critical, as finding the lumen of a deployed device is difficult or impossible.

26  Flow Diversion Treatment of Intracranial Aneurysms

Case Overview

CASE 26.6 Large Ophthalmic Artery Aneurysm: Flow Diversion

• A 45-year-old female presented with headaches and intermittent blurry vision on the left eye. She was seen by ophthalmologist that found mild left optic nerve papilledema. Further work-up revealed a

large intracranial aneurysm. She has a past medical history of familial subarachnoid hemorrhage. • Magnetic resonance angiogram demonstrated a large ophthalmic artery (OphA) aneurysm.

Fig 26.6a  Large ophthalmic artery aneurysm.

Fig 26.6b  Artist’s illustration of PED embolization of large and irregular paraophthalmic ICA aneurysm.

Fig 26.6c  Large and irregular paraophthalmic ICA aneurysm.

Fig 26.6d  Triaxial system access (088 guide catheter [red arrow], 058 intermediate [white arrow], 027 microcatheter [green]).

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Fig 26.6e  Obtaining distal access in the middle cerebral artery with microcatheter (red arrow) and cavernous ICA with intermediate catheter (white arrow).

Fig 26.6f  Flow diversion stent in position prior to deployment.

Fig 26.6g  Flow diversion stent deployment.

Fig 26.6h  Flow diversion stent further deployment.

26  Flow Diversion Treatment of Intracranial Aneurysms

Fig 26.6i  Flow diversion stent deployed.

Fig 26.6j  Adequate aneurysm coverage with aneurysmal flow stasis.

Video 26.6  Flow diversion stenting for complex ophthalmic aneurysm

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Procedure • The patient underwent elective endovascular treatment of large paraophthalmic internal carotid artery (ICA) aneurysm. Patient was given 325 mg aspirin and 75 mg clopidogrel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F dilator. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • Vitek catheter (Cook Medical). • 0.058-inch Navien intermediate catheter (Medtronic). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microguidewire (Stryker). • 4.5 x 20 mm Pipeline Embolization Device Flex (PED) (Medtronic). • 8F AngioSeal percutaneous closure device.

This symptomatic large OphA aneurysm compressing the optic nerve warrants treatment. Because of the large size of the aneurysm and tortuosity of the carotid syphon a triaxial system (large guide catheter, intermediate catheter, microcatheter) was used. The guide catheter was navigated and positioned at the internal carotid artery (ICA). Under road map and magnification, the intermediate and microcatheter were advanced into the cavernous ICA and middle cerebral artery, respectively. The intermediate catheter is maintained in position while the distal segment of the stent is delivered. Once the stent is taking the anterior curve of the carotid syphon, the intermediate catheter is slightly retracted, and this maneuver is continued until the device is fully unsheathed and open. Do not deliver the stent within the intermediate catheter. Once the PED is fully deployed, do not push the stent with the intermediate catheter as this could cause significant stent foreshortening or push the stent into the aneurysm.

Tips, Tricks & Complication Avoidance • In a recent meta-analysis that included 2,458 patients with symptomatic OphA aneurysms treated, authors found that vision improved in 58% (95% CI 48%–68%) of patients after clipping, 49% (95% CI 38%–59%) after coiling, and 71% (95% CI 55%–84%) after flow diversion. These data also demonstrated a high rate of visual improvement after flow diversion without a significant difference in the rate of worsened vision or iatrogenic visual impairment compared with clipping and coiling. These findings suggest that flow diversion is an effective option for treatment of visually symptomatic paraclinoid aneurysms. Flow diversion is hypothesized to reduce mass effect, which may decompress the optic nerve when treating patients with visually symptomatic paraclinoid aneurysms (Neurosurg Focus. 2017;42(6):E15).

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• Internal analysis of the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial demonstrated that, after PED embolization of large and cavernous and supraclinoid internal carotid artery aneurysms demonstrated, excellent neuro-ophthalmological outcomes 6 months after the procedure, with deficits improving in most of the patients (J Neurosurg. 2015;123(4):897–905). • Some patients with large OphA or paraclinoid aneurysms undergoing PED embolization, experience retro-orbital pain and visual floaters several days after the procedure. This is related to aneurysm thrombosis, and as long as patients remain neurologically intact, imaging is usually not necessary. A short course of oral steroids (e.g., dexamethasone 4 mg every 8 h for 7 days) helps in relieving symptoms.

26  Flow Diversion Treatment of Intracranial Aneurysms

Case Overview

CASE 26.7 Fusiform Middle Cerebral Artery Aneurysm: Flow Diversion

• A 78-year-old male presented to the emergency department with transient ischemic attack symptoms consistent with right upper and lower paresthesias. He has a past medical history of hypertension. His neurological exam was normal. • Initial computed tomography (CT) was normal.

• Initial CT angiogram demonstrated a large fusiform middle cerebral artery (MCA) aneurysm. • Patient underwent elective flow diversion stenting of the MCA aneurysm. One-year follow-up cerebral angiography demonstrated aneurysm residual. Aneurysm residual was treated with a second pipeline embolization device (PED) stent.

Fig 26.7a  Residual fusiform MCA aneurysm.

Fig 26.7b  Artist’s illustration of PED embolization of fusiform MCA aneurysm. Inset: double-layer PED.

Fig 26.7c  Left MCA fusiform aneurysm.

Fig 26.7d  Obtaining distal access into superior M2 MCA branch.

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Fig 26.7e  Flow diversion prior to deployment.

Fig 26.7f  Flow diversion stent deployment.

Fig 26.7g  Intra-aneurysmal flow stasis after stent deployment.

Video 26.7  Flow diversion stenting for residual fusiform MCA aneurysm

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Procedure • The patient underwent elective endovascular treatment of residual fusiform left MCA aneurysm with PED. Patient continued with dual-antiplatelet regimen (325 mg aspirin and 75 mg clopidogrel daily). The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • 2.5 x 20 mm PED Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

In general, intracranial fusiform aneurysms are best treated with flow diversion stenting. This fusiform MCA aneurysm was originally treated with PED; however, at 1-year follow-up, there was still significant aneurysm residual requiring treatment with a second PED. After obtaining access in the distal internal carotid artery, under road map and magnification, a 0.027-inch microcatheter is advanced over a 0.014-inch microwire distal into an M2 branch. Ideally, in the larger M2 branch. The ideal landing zone for the PED is at the M1/M2 junction. If the M2 branch makes an acute turn, be aware of the distal delivery tip as this could inadvertently perforate a small M2 branch.

Tips, Tricks & Complication Avoidance • Originally, the Food and Drug Administration approved flow diversion stent for the management of unruptured paraclinoid aneurysms; however, PED is now currently used in posterior circulation and distal (anterior communicating artery, middle cerebral artery) aneurysms with good results (World Neurosurg. 2018;118:e825–e833). • Aneurysm location in the distal anterior circulation (posterior communicating artery, anterior choroidal artery, middle cerebral artery) is a significant predictor of persistent aneurysm filling with less than 80% occlusion. PEDs are designed for parent vessels that are larger than the caliber of distal anterior circulation vessels. In a small

vessel, the device may be elongated, and the stent pores may become larger, which might impair the flow diversion effect and lower the chances of aneurysm thrombosis. Occlusion rate with the PED for MCA aneurysms have been reported to be between 55% and 85%. This rate is lower than the occlusion rate for clipping (90%) in most studies (J Neurosurg. 2018;4:1–7 [Epub ahead of print]). • Flow diversion for MCA aneurysms should only be considered when other surgical or endovascular approaches are not an option or do not offer superior outcomes and for lesions that persist after previous surgery or endovascular treatment.

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CASE 26.8 Giant Middle Cerebral Artery Aneurysm: Flow Diversion

• A 62-year-old female presented to the emergency department with recurrent severe headaches. She has a past medical history of hypertension and a previous large ruptured middle cerebral artery

(MCA) aneurysm treated with endovascular coiling 10 years ago. She was lost to follow-up. Her neurological exam was normal. • Computed tomography (CT) was normal. CT angiogram demonstrated a large recurrent MCA aneurysm.

Fig 26.8a  Fusiform MCA aneurysm.

Fig 26.8b  Artist’s illustration of PED embolization of recurrent large MCA aneurysm.

Fig 26.8c  Left recurrent MCA aneurysm.

Fig 26.8d  Obtaining distal access into superior M2 MCA branch (arrow).

26  Flow Diversion Treatment of Intracranial Aneurysms

Fig 26.8e  Flow diversion prior to deployment.

Fig 26.8f  Flow diversion stent deployment (arrow).

Fig 26.8g  Intra-aneurysmal flow stasis after stent deployment.

Video 26.8  Flow diversion stenting for recurrent large MCA aneurysm

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Procedure • The patient underwent elective endovascular treatment of her recurrent left MCA aneurysm with flow diversion stenting. Patient was given 325 mg aspirin and 75 mg clopidogrel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microguidewire (Stryker). • 2.5 x 20 mm Pipeline Embolization Device (PED) Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

This large fusiform MCA aneurysm was previously treated with endovascular coiling and had recurred after 10 years. Currently, the aneurysm is symptomatic and because it originally presented with subarachnoid hemorrhage, we believe it warrants treatment. A 6F guide catheter was introduced in the internal carotid artery and, under road map, a 0.027-inch microcatheter over a 0.014inch microwire was navigated distal in the upper M2 branch. The microwire is exchanged for the PED. The ideal landing zone is the M1/M2 junction. While unsheathing and pushing the device, we maintained the distal delivery wire tip in sight, and we readjusted the working angiographic view. The tip of the delivery wire is stiff and could perforate a small M2 or M3 branch. We continued unsheathing the PED until complete delivery. Post-stenting angiography demonstrated adequate PED position and intraaneurysmal flow stasis. There was no evidence of distal branch occlusion or perforation.

Tips, Tricks & Complication Avoidance • The second-generation PED, Flex, has several design upgrades, including improved opening and the ability of resheathing in comparison with the original classic PED. The use of resheathing promotes distal opening, improved apposition, and repositioning the device with no associated dissection, perforation, or thromboembolic events. • A stiffer stainless steel pusher wire was introduced to navigate tortuosity and facilitate retracking of the microcatheter. This facilitates

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bumping the device with the microcatheter or intermediate catheter to improve apposition and preserves access in situations in which additional devices or manipulation is needed. • Another important modification was the abandonment of the capture coil in favor of Teflon sleeves and the addition of an angled tip coil. This eliminates the need for torque to release the device and softens the tip of the delivery system to reduce the risk of dissection or perforation.

26  Flow Diversion Treatment of Intracranial Aneurysms

Case Overview

CASE 26.9 Vertebral Artery Aneurysm: Flow Diversion

• A 66-year-old male presented with vertigo, ataxia, and imbalance. His neurological exam was normal. He had a past medical history of hypertension, obesity, and chronic vertigo. The patient had familial history of aneurysmal subarachnoid hemorrhage.

• Magnetic resonance angiogram demonstrated a fusiform left vertebral artery (VA) aneurysm.

Fig 26.9a  Fusiform vertebral artery aneurysm.

Fig 26.9b  Artist’s illustration of PED embolization of fusiform VA aneurysm.

Fig 26.9c  Access into tortuous left VA.

Fig 26.9d  Obtaining distal access with microcatheter.

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Fig 26.9e  Bringing the PED stent through the microcatheter.

Fig 26.9f  Flow diverter stent in position prior to deployment.

Fig 26.9g  Flow diverter stent initial deployment.

Fig 26.9h  Flow diverter stent deployed.

Fig 26.9i  Adequate aneurysm coverage with intra-aneurysmal flow stasis.

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Procedure • The patient underwent elective endovascular treatment of fusiform VA aneurysm with flow diversion. Patient was given 325 mg aspirin and 75 mg clopidogrel daily for 7 days prior to the intervention. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Penumbra). • Vitek catheter (Cook Medical). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • 3.75 x 25 mm Pipeline Embolization Device (PED) Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

Flow diversion stenting is an adequate treatment for fusiform posterior circulation aneurysms. A 6F guide catheter is navigated at the V3 segment of the left VA. Under road map and magnification, a 0.027-inch microcatheter over a 0.014-inch was advanced into the basilar artery. The microwire was exchanged for the PED. The ideal landing zone is at the VA and basilar artery junction. The PED was deployed with a combination of unsheathing and pushing the stent. One single device was used.

Tips, Tricks & Complication Avoidance • Although the initial indication for PED was anterior circulation aneurysms. There are several publications showing acceptable-togood outcomes in posterior circulation aneurysms. A retrospective analysis of a multicenter study of 131 posterior circulation aneurysms demonstrated large fusiform aneurysms were found to have the lowest occlusion rate and the highest frequency of major complications. Dissecting aneurysms, frequently treated in the setting of subarachnoid hemorrhage, occluded most often and had a low complication rate. Saccular aneurysms were associated with predominantly minor complications, particularly in clopidogrel nonresponders (J Neurosurg. 2018;4:1–13. [Epub ahead of print]).

• Increased awareness of variability in the response to clopidogrel and aspirin has led many interventionists to manipulate antiplatelet medications to achieve a goal P2Y12 level, which some have ventured explains lower complication rates. • A study aimed to determine whether a last-recorded P2Y12 reaction units value of < 60 or > 240 predicts thromboembolic and hemorrhagic complications up to 6 months after treatment of cerebral aneurysms with the PED found that P2Y12 value was the only independent predictor of all and major complications (AJNR Am J Neuroradiol. 2014;35(1):128–135).

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CASE 26.10 Giant Basilar Artery Trunk Aneurysm: Flow Diversion

• A 75-year-old male presented with subacute onset of dizziness, diplopia, and blurry vision. His neurological exam was normal. He had past medical history of hypertension, diabetes, coronary artery diseases, and recent coronary artery bypass graft surgery. Among other medications, he is currently taking aspirin and clopidogrel.

• Magnetic resonance angiogram demonstrated a very large partially thrombosed basilar artery (BA) aneurysm with mass effect on brainstem.

Fig 26.10a  Partially thrombosed giant fusiform BA aneurysm.

Fig 26.10b  Artist’s illustration of PED embolization of giant fusiform BA aneurysm.

Fig 26.10c  Giant fusiform BA aneurysm.

Fig 26.10d  Radial approach to the right vertebral artery.

26  Flow Diversion Treatment of Intracranial Aneurysms

Fig 26.10e  Obtaining distal access with microcatheter.

Fig 26.10f  First flow diverter stent deployment.

Fig 26.10g  Second flow diverter (red arrows) deployment. There is some intra-aneurysmal flow stasis after the first flow diverter (white arrow).

Fig 26.10h  Two flow diverter stents overlapping (arrows).

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Fig 26.10i  Adequate aneurysm coverage with intrasaccular flow stasis.

Fig 26.10j  Six-month follow-up computed tomography angiography showing complete aneurysm obliteration and BA reconstruction.

Video 26.10  Flow diversion stenting for basilar artery aneurysm

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26  Flow Diversion Treatment of Intracranial Aneurysms

Procedure • The patient underwent elective endovascular treatment of giant BA aneurysm with flow diversion. Patient continued his dual antiplatelet regimen of 325 mg aspirin and 75 mg clopidogrel daily. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.027-inch Marksman microcatheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • 4 x 30 mm Pipeline Embolization Device (PED) Flex (Medtronic). • 5 x 30 mm Pipeline Embolization Device Flex (Medtronic). • 6F AngioSeal percutaneous closure device.

Large BA aneurysms carry a significant high risk of rupture and should be treated. The current patient has a large symptomatic BA aneurysm with significant brainstem compression. Flow diversion stenting is an adequate treatment for these complex vascular lesions. A 6F guide catheter was navigated at the V3 segment of the left vertebral artery. Under road map, a 0.027-inch microcatheter advanced distal into one of the posterior cerebral arteries (PCAs). The ideal landing zone for the PED is at the BA/PCA junction, to allow for stent foreshortening and still have adequate distal aneurysm coverage. The PED is slowly unsheathed with minimal wire pushing as this could make the PED prolapse into the large aneurysms. Once the PED is deployed, the microcatheter is advanced distal into the PCA again. A second PED is loaded and deployed, telescoping with the first PED until a segment of normal vertebral artery (VA) is covered by the stent. Do not hesitate to add a third PED if the VA is still not covered with a stent. A third PED was not necessary in the current case. Perform several follow-up angiograms before removing the guide catheter. Look for fast (within 1–2 h after deployment) aneurysm thrombosis, as the thrombus could reach the parent vessel and thromboembolic complications might occur. We recommend 24–48 h anticoagulation after PED deployment.

Tips, Tricks & Complication Avoidance • Endovascular techniques for the treatment of large basilar or vertebrobasilar include flow diversion alone, flow diversion with coils, flow diversion with vertebral artery occlusion, or flow diversion with coils and vertebral artery occlusion. • Rapid aneurysm thrombosis, usually within several hours after PED deployment, could have the risk of intravascular thrombus expansion and occlusion. We strongly suggest adding anticoagulation for 24–48 h after the endovascular procedure.

• A multicenter experience of endovascular treatment of large and giant carotid aneurysms with flow-diverter stents alone or in combination with coils demonstrated that clinical outcomes and rates of intraoperative and postoperative complications did not differ significantly between the groups. There were better anatomic results using PED combined with coils, which were documented 6 months after the procedure. Use of PED and coils provide a higher aneurysm occlusion rate and reduce the need for retreatment (Oper Neurosurg (Hagerstown). 2017;13(4):492–502).

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27  Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB) Gary B. Rajah, Leonardo Rangel-Castilla, Willem Jan van Rooij, and Jo P. Peluso

General Description Intrasaccular devices are an alternative to endovascular primary coiling, stent-assisted coiling, and flow diversion (FD). Because antiplatelet therapy is not required, these devices have become an attractive option for use in ruptured intracranial aneurysms. They are typically used for wide-necked bifurcation-type aneurysms. As the device is placed within the aneurysmal sac, the amount of metal exposed to the parent vessel and, therefore, the amount of metal that must be endothelialized, are greatly reduced compared to endoluminal devices (i.e., FDs such as the pipeline embolic device [PED], Medtronic and the flow redirection endoluminal device). This makes the intrasaccular device less thrombogenic to the parent vessel, while possessing the same flow-diverting properties at the aneurysm neck as endoluminal devices. Intrasaccular devices have the added benefit of being deployed once and diverting flow at the aneurysm neck, as opposed to conventional coiling procedures, which rely on the packing density of the entire aneurysm sac and often involve multiple coil deployments. Intrasaccular devices include the Woven Endo Bridge (WEB, Sequent Medical). The WEB is composed of braided wires made of nitinol (a nickel-titanium alloy) that provide 35%–45% metal coverage. The device has an inner and outer wire mesh and comes in spherical and cube shapes. Available diameters range from 4 to 11 mm. The WEB can be fully retrieved until final detachment by an electrothermal detachment system contained in a handheld controller. The device has been tested largely in bifurcation aneurysms of the basilar apex, internal carotid artery, and middle cerebral artery, with short-term adequate occlusion rates of 70%–90%. (Adequate occlusion refers to a small amount of lateral recess filling posttreatment). Some study investigators have noted rates of intraprocedural thromboembolic events of 15%–17%. The investigators of the WEB Clinical Assessment of Intrasaccular Aneurysm Therapy 2 (WEBCAST-2) study1 noted 79% adequate occlusion and 1-month morbidity rates of 1.8%. Other intrasaccular devices include the LUNA aneurysm embolization system (LUNA AES, Medtronic), which consists of a double-layer nitinol mesh and the Medina Embolic Device (Medtronic), which is a 3D coil that assumes a spherical shape on deployment.

Indications Intrasaccular FD devices are indicated for wide-necked bifurcation type aneurysms. There is no need for dual antiplatelet therapy unlike intraluminal FDs. However, new data suggest differences in thromboembolic rates between patients with the WEB on no antiplatelet agent versus those on a single antiplatelet agent.1

Neuroendovascular Anatomy The cerebral circulation has been detailed in previous chapters. Anatomical points pertinent to the use and deployment of the WEB relate to aneurysm shape, which may not always be spherical. The device must be sized appropriately and deployed in such a way as to keep it at the aneurysm neck where it can divert flow. Simply placing the device within the aneurysm (floating) will have little treatment response. Like endoluminal devices, wall apposition is important. Coils may be necessary as an adjuvant therapy to the WEB to aid in ideal

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neck apposition. The WEB is slightly stiffer than traditional coils and requires a larger microcatheter than most coils, thus tortuous anatomy can present a challenge in accessing the aneurysm. Many authors recommend oversizing the WEB for better apposition. Measurements of the average aneurysmal width and smallest height are utilized for sizing. As opposed to coils, stents or balloons are rarely necessary for WEB deployments, even in wide-necked aneurysms.

Perioperative Medications Given the larger catheter size necessary for WEB deployment, these procedures are performed under systemic heparinization. The procedure is performed under conscious sedation with local sedation or general anesthesia.

Specific Technique and Key Steps 1. After a femoral angiogram has been performed to confirm the absence of any irregularity or dissection, the guide catheter is placed over a curved wire or diagnostic catheter (0.035-inch angled Glidewire, Terumo) and advanced into the aorta under fluoroscopic guidance. 2. The guide catheter is placed in the extracranial vessel of choice utilizing roadmap navigation. 3. We recommend the use of an intermediate guide catheter in cases of vessel tortuosity for more catheter support. The WEB device is stiff, and good stability is needed. An intermediate guide catheter can help. 4. For device delivery, a 0.027- to 0.033-inch microcatheter is connected to a heparinized flush. 5. Under anteroposterior (AP) and lateral roadmap views, the intermediate guide catheter (if utilized) is placed over the microcatheter wire approximately 1 cm proximal to the aneurysm neck. If that position is not possible, the intermediate guide catheter is left safely in a vessel that will accommodate its size. 6. The optimal working views of the aneurysm are identified on magnified AP and lateral fluoroscopy (Fig. 27.1-27.3, Video 27.127.3). 7. The microcatheter is navigated into the aneurysm neck and about two-thirds of the way into the dome (Video 27.1-27.3). 8. The correct WEB device is selected based on the sizing chart and loaded within the microcatheter. 9. The WEB device is pushed until flush with the microcatheter. The device has proximal and distal radiopaque markers (Video 27.127.3). 10. Deployment is done utilizing some unsheathing of the device with some pushing to help expand the device; the device can be withdrawn into the large part of the aneurysm to aid in selfexpansion and reseated once fully deployed (Fig. 27.1-27.3, Video 27.1-27.3). 11. The device can be resheathed if necessary. If positioning is satisfactory (final angiographic runs demonstrate slow stasis, good apposition), electrothermal detachment can be completed with the detachment handle. 12. Subsequently, the microcatheter can be removed.

27  Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)

Device Selection

Pearls

In our practice, the following are common set-ups and devices used for WEB deployment. • 6–8 French (F) sheath depending on a bi- or triaxial platform. • 8F guide catheter (90 cm Neuron MAX, Penumbra). • 0.058-inch intermediate catheter (Navien, Medtronic; Catalyst 5, Stryker; or Phenom, Medtronic). • 0.035-inch angled Glidewire. • 125-cm 5F diagnostic catheter (Vitek, Cook). • 0.027-inch microcatheter (Marksmen, Medtronic), Headway 27 (MicroVention), Phenom (Medtronic), VIA (Sequent). – Synchro 2 standard wire (0.014-inch wire) (Stryker). – Intrasaccular device. – Continuous heparinized flush.

• Oversizing the WEB will aid in stability and neck apposition. • Intermediate catheters will aid in microcatheter stability during WEB deployment. • Jailing a microcatheter can be utilized for adjunctive coiling. • The WEB can be utilized in the setting of a ruptured aneurysm (Fig. 27.1-27.3, Video 27.1-27.3). • Thromboembolic complications can be treated with a glycoprotein IIa/ IIIb inhibitor. Large occlusions can be treated with thrombectomy. • Because tension builds up in the stiff WEB system, extreme care must be taken to avoid driving the microcatheter through the aneurysm dome (Video 27.1-27.3). • WEB compression with aneurysm recanalization can occur. Rescue strategies include endoluminal FD.

Reference [1] Pierot L, Moret J, Barreau X, et al. Safety and efficacy of aneurysm treatment with WEB in the cumulative population of three prospective, multicenter series. J Neurointerv Surg. 2018;10(6):553–559.

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Case Overview

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CASE 27.1 Ruptured Anterior Communicating Artery Aneurysm: Woven Endobridge Device

• A 36-year-old female presented to the emergency department complaining of “the worst headache of her life.” Neurologically, the patient was awake, alert, and oriented. Pupils were reactive and symmetric. She was following commands in all four extremities with no obvious focal neurological deficits. She had no past medical history of importance.

• Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) in all basal cisterns. CT angiography demonstrated an anterior communicating artery (ACoA) aneurysm .

Fig 27.1a  CT showing severe SAH.

Fig 27.1b  CT angiography demonstrating ACoA aneurysm.

Fig 27.1c  Artist’s illustration of a ruptured ACoA aneurysm treated with intrasaccular flow diversion.

Fig 27.1d  Microcatheter positioned at the proximal third of the aneurysm.

27  Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)

Fig 27.1e  Initiation of WEB delivery.

Fig 27.1f  WEB fully delivered but still attached.

Fig 27.1g  Angiography immediately after device deployment showing aneurysm thrombosis.

Fig 27.1h  Complete aneurysm obliteration at 3-month follow-up angiography.

Video 27.1  Intrasaccular flow diversion for ACoA aneurysm

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Procedure • The patient underwent endovascular embolization of ACoA aneurysm with intrasaccular flow diversion. The procedure was performed under general anesthesia and through a right femoral artery approach. 3,000 units of heparin was given once the guide catheter was advanced into the internal carotid artery.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch microcatheter (Stryker). • 0.014-inch Transend microwire (Stryker). • WEB device (Microvention). • 6F AngioSeal percutaneous closure device.

This is a rupture ACoA aneurysm with a relatively narrow neck. The aneurysm arises straight from the parent vessel and both A2s are symmetric in relation to the aneurysm. These anatomy characteristics make intrasaccular flow diversion an adequate option in treatment. A 6F guide catheter was navigated in the internal carotid artery. Under roadmap and magnification, a 0.021inch microcatheter was advanced over a 0.014-inch microwire into the aneurysm. The microcatheter was positioned at the proximal third of the aneurysm. The WEB device was advanced, and while maintaining the position of the microcatheter, the device was slowly delivered. The distal tip of the device should stay away from the aneurysm tip (presumable ruptured site) if possible. Once the device was fully expanded, we performed an angiography run to confirm adequate positioning and intra-aneurysmal flow stasis. The device was then detached electrolytically.

Tips, Tricks & Complication Avoidance • WEB device is available in two different shapes: SL or SLS. WEB SL sizes range from 4 x 2 mm to 11 x 9 mm. WEB SLS sizes range from 4 mm to 11 mm. Delivering microcatheter sizes vary according to the device size (0.021-, 0.027-, and 0.033-inch). • The WEB is a nitinol-based braided-wire intravascular device designed to be used for treating wide-necked bifurcation aneurysms; it spans the aneurysmal neck to disrupt inflow and reduce intrasaccular flow, thereby resulting in thrombosis. The smooth and dense surface of the

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WEB can allow endothelial cells to bridge the neck of the aneurysm and support subsequent vessel wall reconstruction. • The technical success rate ranged from 92.9% to 98.7%, adequate occlusion at 1 year ranged from 80% to 82%, and procedural morbidity ranged from 1.8% to 2.7%, with no mortalities reported. Thromboembolic events occurred in 4.7% to 15.6% of patients (AJNR Am J Neuroradiol. 2017;38:1151–1155). • Patients do not require antiplatelet therapy.

27  Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)

Case Overview

CASE 27.2 Ruptured Middle Cerebral Artery Aneurysm: Woven Endobridge Device

• A 47-year-old male presented to the emergency department complaining of severe headaches over the last 3 days and recent onset of confusion. Neurologically, the patient was awake, alert, confused, oriented to person and place only. Pupils were reactive and symmetric. He was following commands in all four extremities. There

were no focal neurological deficits. He had a past medical history of hypertension and familial history of subarachnoid hemorrhage (SAH). • Computed tomography (CT) showed diffuse SAH and mild hydrocephalus. Computed tomography (CT) angiography demonstrated a middle cerebral artery (MCA) aneurysm.

Fig 27.2a  CT showing right Sylvian fissure SAH and mild hydrocephalus.

Fig 27.2b  CT angiography demonstrating MCA aneurysm with moderate vasospasm.

Fig 27.2c  Artist’s illustration of a ruptured MCA aneurysm treated with intrasaccular flow diversion.

Fig 27.2d  Microcatheter positioned at the center of the aneurysm.

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Fig 27.2e  Initial position prior to deployment.

Fig 27.2f  WEB device halfway deployed within the aneurysm.

Fig 27.2g  WED device fully deployed and detached.

Fig 27.2h  Angiography immediately after deployment showing aneurysm obliteration.

Fig 27.2i  Complete aneurysm obliteration at 6-month follow-up angiography.

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27  Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB) Video 27.2  Intrasaccular flow diversion for MCA aneurysm

Procedure • The patient underwent endovascular embolization of MCA aneurysm with intrasaccular flow diversion. The procedure was performed under general anesthesia and through a right femoral artery approach. 3,000 units of heparin were given once the guide catheter was advanced into the internal carotid artery.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch microcatheter (Stryker). • 0.014-inch Transend microwire (Stryker). • WEB device (Microvention). • 6F AngioSeal percutaneous closure device.

This is a ruptured wide-necked MCA aneurysm. The aneurysm arises from the superior M2 branch and projects inferiorly. An adequate option for this square-shaped aneurysm is an intrasaccular flow diversion. A 6F guide catheter was navigated at the petrous internal carotid artery. Under roadmap and magnification, a 0.021-inch microcatheter was advanced over a 0.014-inch microwire into the aneurysm. The microcatheter was positioned at the center of the aneurysm. The WEB device was advanced, and while maintaining the position of the microcatheter, the device was slowly delivered. The device should not be in close proximity to the fundus of the aneurysm. As long as the device covers the proximal 2/3s of the aneurysm, the aneurysm will occlude. An angiography run confirmed adequate device positioning and intra-aneurysmal flow stasis. The device was then detached electrolytically. In this particular case, the proximal tip of the device stayed inside the parent artery and aspirin is recommended.

Tips, Tricks & Complication Avoidance • The WEB Clinical Assessment of Intrasaccular Aneurysm Therapy (WEBCAST) trial was a prospective European trial evaluating the safety and efficacy of WEB in wide-neck bifurcation aneurysms. Treatment with WEB was achieved 94.1%. Adjunctive implants (coils/stents) were used in four of 48 aneurysms (8.3%). Thromboembolic events were observed in 17.6%, resulting in a permanent deficit (modified Rankin Scale [mRS] score 1) in one patient (2.0%). Intraoperative rupture was not observed. Success was achieved at 6 months in 85.4% of patients treated with WEB: 23 of 41 patients (56.1%) had complete occlusion, 12 of 41 (29.3%) had a neck remnant, and six of 41 (14.6%) had an aneurysm remnant (J Neurosurg. 2016;124(5):1250–1256).

• WEBCAST 2 was designed to evaluate the WEB Single-Layer with Enhanced Visualization. Ten European neurointerventional centers included 55 patients. Procedural morbidity and mortality at 1 month were, respectively, 1.8% (1/55 patients) and 0.0% (0/55 patients). Morbidity and mortality at 1 year were, respectively, 3.9% (2/51 patients) and 2.0% (1/51 patients). At 1 year, complete occlusion was observed in 27/50 aneurysms (54.0%); neck remnant, in 13/50 (26.0%); and aneurysm remnant, in 10/50 (20.0%) (adequate occlusion in 40/50, 80.0%). WEBCAST 2 confirms the high safety and efficacy of WEB aneurysm treatment demonstrated in the WEBCAST (AJNR Am J Neuroradiol. 2017;38(6):1151–1155).

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Case Overview

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CASE 27.3 Ruptured Posterior Communicating Aneurysm: Woven Endobridge Device

• A 61-year-old female presented to the emergency department complaining of sudden onset of severe headaches and double vision. Neurologically, the patient was awake, alert, and confused. She also had a complete right oculomotor nerve palsy. She was following

commands in all four extremities with no other focal neurological deficits. She had a past medical history of hypertension and diabetes. • Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) and moderate hydrocephalus. CT angiography demonstrated a right posterior communicating artery (PCoA) aneurysm.

Fig 27.3a  CT showing SAH in all basal cisterns and hydrocephalus.

Fig 27.3b  CT angiography demonstrating PCoA aneurysm arising directly from the PCoA.

Fig 27.3c  Artist’s illustration of a ruptured PCoA aneurysm treated with intrasaccular flow diversion.

Fig 27.3d  Advancing microcatheter over microwire into the aneurysm.

27  Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB)

Fig 27.3e  Microcatheter positioned at the aneurysm. The guide catheter was advanced further into the internal carotid artery to better support the upcoming WEB device.

Fig 27.3f  WEB device halfway deployed within the aneurysm.

Fig 27.3g  WED device fully deployed.

Fig 27.3h  WED device fully deployed and detached.

Fig 27.3i  Angiography after device deployment demonstrating excellent aneurysm obliteration and PCoA patency.

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V  Intracranial Aneurysms Video 27.3  Intrasaccular flow diversion for PCoA aneurysm

Procedure • The patient underwent endovascular embolization of PCoA aneurysm with intrasaccular flow diversion. The procedure was performed under general anesthesia and through a right femoral artery approach. 3,000 units of heparin were given once the guide catheter was advanced into the internal carotid artery.

Device List

Device Explanation

• Standard femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch microcatheter. • 0.014-inch Transend microwire (Stryker). • WEB device (Microvention). • 6F AngioSeal percutaneous closure device.

This is a ruptured PCoA aneurysm presented with third cranial nerve palsy. The aneurysm arises from the PCoA and not from the internal carotid artery (ICA). The large PCoA is fetal. Flow diversion or coiling are not adequate options because PCoA will prevent aneurysm occlusion or coils could occlude the parent artery. Intrasaccular flow diversion is an excellent alternative. The 6F guide catheter is navigated at the cervical ICA. A 0.021-inch microcatheter is advanced into the aneurysm. The guide catheter is further advanced into the petrous ICA for more microcatheter support. The WEB device is slowly advanced into the aneurysm; at the same time, the microcatheter is slowly pulled back. Once the device is fully expanded, an angiography is performed to assess for aneurysm flow stasis and PCoA patency. The device is then detached.

Tips, Tricks & Complication Avoidance • Results of cumulative population from three prospective multicenter series (WEBCAST, WEBCAST2, French Observatory) demonstrated the safety and efficacy of the WEB device. It included 168 patients and 169 aneurysms. The majority of the aneurysms were located in the anterior circulation (middle cerebral artery (MCA) (50.9%), anterior communicating artery (ACoA) (21.3%), ICA terminus (10.1%). There were no mortalities and procedure/device-related morbidity was 1.2%. At 1 year, complete aneurysm occlusion was seen in 52.9%, neck

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remnant in 26.1%, and aneurysm remnant in 20.9%. Retreatment was done in 6.9% (J Neurointerv Surg. 2018;10(6):553–559). • WEB device requires a large size microcatheter (0.027-inch microcatheter for the smaller WEB device) and could be challenging for distal aneurysm (e.g., MCA, ACoA) or tortuous vessels. • It is common for the proximal end of the WEB device to stay outside the aneurysm sac and within the parent vessel. Patients might need antiplatelet therapy as this could be thrombogenic.

28  Novel Aneurysm Neck Reconstruction Devices Stephan A. Munich and Leonardo Rangel-Castilla

General Description Cerebral aneurysms located at bifurcations often provide a unique challenge for endovascular treatment. They require protection of at least three parent vessels. Additionally, the hemodynamic forces acting in these locations may increase the risk of coil compaction. Widenecked bifurcation aneurysms add an additional layer of complexity. Stent-assisted coiling of bifurcation aneurysms requires unique stent constructs, such as Y or X stenting. These complex stenting configurations have been reported to increase the rate of procedurerelated complications compared to coiling alone. The PulseRider (Pulsar Vascular) is a self-expanding nitinol implant that is intended to serve as a “neck bridge for wide-necked aneurysms arising at or near a vessel bifurcation.” It is designed to minimize metal exposure while serving a buttress to maintain coils within the aneurysm sac. The Barrel vascular reconstruction device (VRD) (Medtronic) is a self-expanding nitinol stent. Its unique design, with a bulged central component, is intended to allow for greater neck coverage. It is constructed with a double spiral strut, which is meant to conform to the tortuous anatomy encountered at vessel branch points. It has 12 platinum marker bands.

Evidence Both the PulseRider and Barrel VRD are novel devices, and their longevity and long-term success are yet to be determined. The Adjunctive Neurovascular Support of Wide-neck Aneurysm Embolization and Reconstruction (ANSWER) Trial included 34 patients with wide-necked carotid terminus or basilar apex aneurysms treated with the PulseRider.1 Immediate Raymond-Roy occlusion grade 1 or 2 was achieved in 82.4% and increased to 87.9% at the 6-month followup. Good neurologic outcome (modified Rankin Scale [mRS] score < 2) occurred in 94% at 6 months. A multicenter, prospective postmarket study of the Barrel VRD included 20 patients with wide-necked bifurcation aneurysms.2 The primary effectiveness endpoint (Raymond-Roy occlusion grade 1 or 2 in the absence of retreatment, parent artery stenosis [> 50%], or target aneurysm rupture) was achieved in 78.9% of study patients, with a morbidity rate of 5.3%. The German experience echoed these findings with 95% of patients achieving a Raymond-Roy occlusion grade of 1 after a median follow-up of 282 days.3

Indications Novel neck reconstruction devices have been specifically designed to address the challenge of wide-necked aneurysms encountered in endovascular management. PulseRider and Barrel VRD are indicated for these aneurysms when they occur at bifurcations or branch points.

Neuroendovascular Anatomy Anatomy pertinent to the use and deployment of neck reconstruction devices relates to aneurysm neck shape and the angle that it forms with the arteries of parent(s), which is very variable. The devices must be sized appropriately and deployed in such a way as to cover the aneurysm neck to maintain the coil mass within the aneurysm. For use of the Barrel VRD, it is important to measure the diameter of the parent vessel and the triangle formed by the parent vessel, bifurcation vessels, and the neck of the aneurysm. The diameter of this

triangle would provide the size of the bulged central component needed (Fig. 28.1-28.3, Video 28.1-28.3). For use of the PulseRider device, it is important to measure the diameter of the inflow vessel and the angle formed by the inflow vessel (e.g., basilar artery) and the bifurcation arteries (e.g., posterior cerebral arteries). The diameter of the inflow vessel should be between 2.7–4.5 mm. The device comes in “Y” and “T” shapes. A Y-shaped device fits best where the aneurysm and branch vessels are angled 90–120° relative to the axis parent vessel (inflow vessel). A T-shaped device fits best where both of the branch artery angles are < 90° relative to the axis of the parent vessel (Fig. 28.4, 28.5, Video 28.4, 28.5). An understanding of the complex vascular anatomy and hemodynamics occurring at bifurcations and branch points is critical when considering use of these novel devices. For the PulseRider, it is important to understand the landing zones for the limbs of the device. For the Barrel VRD, appreciating the angle of branch vessels is critical to allow for correct deployment of the device and coverage of the neck.

Periprocedure Medications Both these neck reconstruction devices necessitate that patients be placed on dual antiplatelet therapy. The ANSWER trial maintained patients on dual antiplatelet therapy for 6 months after treatment. It is our practice to begin the dual antiplatelet regimen 5–7 days prior to the procedure with aspirin 325 mg daily and clopidogrel 75 mg daily. When this is not possible, loading doses of both medications (aspirin 650 mg and clopidogrel 600 mg) are administered immediately prior to the procedure. We continue dual antiplatelet therapy for 6 months after the procedure, whereas the aspirin is continued indefinitely. As we do with all intracranial endovascular interventions, it is our practice to systemically heparinize the patient. This is confirmed by an activated coagulation time of 250–300 s.

Specific Technique and Key Steps 1. A 6 or 8 French (F) sheath is placed in the femoral artery. 2. A guide catheter is placed in the distal cervical segment of the appropriate vessel (e.g., internal carotid artery [ICA] or vertebral artery). 3. A 3D angiogram is performed to assess aneurysm and parent vessel morphology. 4. Under roadmap guidance, the microcatheters (and intermediate catheter, if used) are advanced. 5. A second microcatheter is advanced into the aneurysm. We routinely deploy one or two loops of coil into the aneurysm prior to deployment of the neck reconstruction device (Video 28.1-28.3). 6. Control injections are performed at the working angles to ensure aneurysm obliteration, stent patency, and adequate wall apposition. 7. Control injections are performed with full views of the intracranial vasculature to assess for delayed capillary filling, distal emboli, or vessel extravasation.

Device Selection The following devices are typically selected when using aneurysm neck reconstruction devices. • 6 or 8 F sheath. • 6F guide catheter (Envoy XB, DePuy Synthes; Benchmark, Penumbra) or 8F guide catheter (Neuron MAX, Penumbra). • Intermediate catheter (Distal Access Catheter, Stryker).

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V  Intracranial Aneurysms • PulseRider—Selection of T- or Y-shaped device based on bifurcation anatomy (Fig. 28.4, 28.5, Video 28.4, 28.5). – 0.021-inch microcatheter. • Barrel VRD. (Fig. 28.1-28.3, Video 28.1-28.3) – 0.021-inch microcatheter. • Coils.

Pearls • The PulseRider device is indicated for the treatment of wide-necked aneurysms with a neck width ≥ 4 mm or a dome-to-neck ratio < 2 that originate on or near a vessel bifurcation of the basilar tip or ICA (Fig. 28.4, 28.5, Video 28.4, 28.5). Other aneurysm locations (anterior communicating artery and middle cerebral artery) for the use of this device are under investigation (NAPA Study, https://www. clinicaltrials.gov/ct2/show/NCT03383666). • The PulseRider is not indicated for patients with severe intracranial vessel tortuosity or anatomy that would preclude a safe introduction of the device. • The Barrel VRD can be used on wide-necked aneurysms at any anatomical location (Fig. 28.1-28.3, Video 28.1-28.3).

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• Be cautious when maneuvering the coiling microcatheter through the tines of the PulseRider device because it can move and dislodge from a previously adequate position (Video 28.4, 28.5). • Do not torque or rotate the PulseRider delivery wire unless the implant distal markers are constrained within the microcatheter. Torquing the device with the implant deployed and engaged in the vasculature can cause vessel damage or dissection. • Carefully observe while deploying coils to ensure that the coils do not prolapse through the neck of the aneurysm or implant arch (applies to the PulseRider and Barrel VRD).

References [1] Spiotta AM, Derdeyn CP, Tateshima S, et al. Results of the ANSWER trial using the PulseRider for the treatment of broad-necked, bifurcation aneurysms. Neurosurgery. 2017;81(1):56–65. [2] Gory B, Blanc R, Turjman F, Berge J, Piotin M. The Barrel vascular reconstruction device for endovascular coiling of wide-necked intracranial aneurysms: a multicenter, prospective, post-marketing study. J Neurointerv Surg. 2018;10(10):969–974. [3] Kabbasch C, Mpotsaris A, Maus V, Altenbernd JC, Loehr C. The Barrel vascular reconstruction device: a retrospective, observational multicenter study. Clin Neuroradiol 2018 Jan 9. [Epub ahead of print]

28  Novel Aneurysm Neck Reconstruction Devices

Case Overview

CASE 28.1 Wide-Necked Middle Cerebral Artery Aneurysm: Neck Reconstruction (Barrel)

• A 62-year-old male presented with a rupture anterior communicating artery aneurysm treated with endovascular coil embolization. The patient recovered completely. He also had a past medical history of hypertension, obesity, and smoking.

• Four-year follow-up computed tomography (CT) angiogram demonstrated a de novo right wide-necked middle cerebral artery (MCA) aneurysm.

Fig 28.1a  CT angiogram showing the right MCA aneurysm.

Fig 28.1b  3D CT angiogram reconstruction showing the right MCA aneurysm.

Fig 28.1c  Artist’s illustration of a wide-necked MCA aneurysm treated with neck reconstruction Barrel device and coils.

Fig 28.1d  3D reconstruction of the right MCA aneurysm.

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Fig 28.1e  Stenting microcatheter at an M2 MCA branch.

Fig 28.1f  Barrel device deployment. Distal marker (green arrow), middle marker (white marker), and proximal marker (red marker).

Fig 28.1g  Coiling microcatheter through the barrel device into the aneurysm.

Fig 28.1h  Coiling.

Fig 28.1i  Complete aneurysm obliteration.

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28  Novel Aneurysm Neck Reconstruction Devices Video 28.1  Neck remodeling device-assisted coiling of an MCA aneurysm

Procedure • The patient underwent elective endovascular treatment of wide-necked right middle cerebral artery aneurysm with neck reconstruction device and coiling. Patient continue his dual antiplatelet regimen of 325 mg aspirin and 75 mg clopidogrel daily. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activate clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch Prowler Select LP ES microcatheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • 3.5 x 5 x 20 mm Neck Reconstruction Device Barrel (Medtronic). • Multiple coils. • 6F AngioSeal percutaneous closure device.

The Barrel vascular reconstruction device is a novel stent that allows endovascular coiling of wide-necked bifurcation aneurysms. This patient with de novo MCA aneurysm formation and past history of ruptured aneurysm should be treated. A 6F guide catheter was navigated at the internal carotid artery and, under road map and magnification, a 0.021-inch microcatheter was advanced into the inferior M2 branch and the Barrel device deployed. The device was deployed in such a way that the central markers were aligned with the aneurysm neck. A second 0.0165inch microcatheter was advanced through the stent device and into the aneurysm. Multiple coils were advanced into the aneurysm until complete aneurysm obliteration was achieved. The delivery wire was detached from the Barrel device by electrolytic means.

Tips, Tricks & Complication Avoidance • The Barrel device is a self-expanding, fully retrievable laser cut nitinol stent. The device has a bulged central component, which allows for greater neck coverage and a double spiral strut construction that allows it to hinge to conform to tortuous anatomy at vessel branch points. It has 12 platinum marker bands. The proximal marker band

attaches to a wire that pushes the device through a 0.021-inch inner diameter microcatheter to the intended treatment site. • There are two options for coiling aneurysms using the Barrel device, jailing technique, or advancing the coiling microcatheter through the device into the aneurysm; it all depends on neurosurgeon or interventionist preference.

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Case Overview

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CASE 28.2 Large Wide-Necked Middle Cerebral Artery Aneurysm: Neck Reconstruction (Barrel)

• A 79-year-old male presented to the emergency room with acute onset of headaches, nausea, and vomiting. His neurological exam was normal. He had a past medical history of hypertension, hypercholesterolemia, coronary artery disease, and ulcerative colitis. His current medications include aspirin and clopidogrel.

• Computed tomography (CT) was normal. CT angiogram demonstrated a large, right, wide-necked middle cerebral artery (MCA) aneurysm.

Fig 28.2a  CT angiogram showing the right MCA aneurysm.

Fig 28.2b  3D CT angiogram reconstruction showing the right MCA aneurysm.

Fig 28.2c  Artist’s illustration of a wide-necked MCA aneurysm treated with neck reconstruction Barrel device and coils.

Fig 28.2d  Anterposterior and lateral angiogram showing the right MCA aneurysm.

28  Novel Aneurysm Neck Reconstruction Devices

Fig 28.2e  Stenting microcatheter at an M2 MCA branch.

Fig 28.2f  Barrel device deployment. Distal marker (green arrow), middle markers (white markers), and proximal markers (red markers).

Fig 28.2g  Coiling.

Fig 28.2h  Complete aneurysm obliteration.

Video 28.2  Neck remodeling device-assisted coiling of a complex MCA aneurysm

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Procedure • The patient underwent elective endovascular treatment of wide-necked right middle cerebral artery aneurysm with neck reconstruction device and coiling. Patient continued his dual antiplatelet regimen of 325 mg aspirin and 75 mg clopidogrel. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch Prowler Select LP ES microcatheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • 3.5 x 5 x 20 mm Neck Reconstruction Device Barrel (Medtronic). • Multiple coils. • 6F AngioSeal percutaneous closure device.

Treatment options for this patient with a wide-neck MCA aneurysm include surgery, stent-assisted (“Y”) coiling, or neck reconstruction device and coiling. The first two options were excluded because of patient’s medical condition and the complexity and high risk of “Y” stenting. Patient was treated with Barrel-assisted coiling. A 6F guide catheter was navigated at the internal carotid artery and, under road map and magnification, a 0.021-inch microcatheter was advanced into the superior M2 branch. The aneurysm neck was incorporated with the superior M2 branch. The Barrel device was advanced and deployed; the central markers were aligned with the aneurysm neck. A second 0.0165-inch microcatheter was advanced through the stent device and into the aneurysm. Multiple coils were advanced into the aneurysm until complete aneurysm obliteration was achieved. Finally, the device was detached electrolytically.

Tips, Tricks & Complication Avoidance • The Barrel vascular reconstruction device is designed similar to a balloon-assisted approach with stenting providing coil containment and branch vessel patency with one device. The barrel section of the device herniates over the ostium and reduces the aneurysm neck to support coiling. • The effect obtained from the Barrel segment of the devices simulates the effect of a “Y” configuration stent. Single Barrel devices covers both parent arteries associated with a bifurcation aneurysm.

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• Device size selection should take into consideration proximal and distal end vessel diameter, and, most importantly, Barrel diameter and length, which corresponds to the distance between the parent vessel branch origin to the contralateral aneurysm neck/parent vessel junction. If the device is not sized appropriately, it would not cover the entire aneurysm neck or inadequate stability with potential migration.

28  Novel Aneurysm Neck Reconstruction Devices

Case Overview

CASE 28.3 Enlarging Wide-Necked Basilar Apex Aneurysm: Neck Reconstruction (Barrel)

• A 47-year-old male with history of a ruptured anterior communicating artery aneurysm treated 5 years ago. At the time, he had a small basilar apex (BA) aneurysm that was treated conservatively. The patient recovered completely from the subarachnoid hemorrhage. Patient was lost to follow-up. He presents now with new onset of

headaches. He had past medical history of hypertension and smoking. His neurological exam is intact. • Computed tomography (CT) is normal. CT angiogram demonstrated enlargement of the BA aneurysm.

Fig 28.3a  Original CT angiogram showing small BA aneurysm.

Fig 28.3b  Current 3D CT angiogram demonstrating significant BA aneurysm growth.

Fig 28.3c  Artist’s illustration of an enlarging wide-necked BA aneurysm treated with neck reconstruction Barrel device and coils.

Fig 28.3d  Obtaining measurements of the BA aneurysm to proper Barrel selection.

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Fig 28.3e  Stenting and coiling microcatheters in position prior to device deployment.

Fig 28.3f  Barrel device deployment. Distal marker (green arrow), middle marker (white marker), and proximal marker (red marker).

Fig 28.3g  Coiling. Coil mass on the right from other previous aneurysm treatment.

Fig 28.3h  Aneurysm obliteration (Raymond-Roy II).

28  Novel Aneurysm Neck Reconstruction Devices Video 28.3  Neck remodeling device-assisted coiling of a basilar apex aneurysm

Procedure • The patient underwent elective endovascular treatment of wide-necked right middle cerebral artery aneurysm with neck reconstruction device and coiling. Patient started dual antiplatelet regimen of 325 mg aspirin and 75 mg clopidogrel daily 7 days prior to the procedure. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activating clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit (2). – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch Prowler Select LP ES microcatheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • 3.5 x 5 x 20 mm Neck Reconstruction Device Barrel (Medtronic). • Multiple coils. • 6F AngioSeal percutaneous closure device.

This wide-necked BA aneurysm is a good candidate for a Barrel neck reconstruction device and coiling. Other alternatives include surgery and “Y” stent-assisted coiling. A 6F guide catheter was advanced at the V3 segment of the left vertebral artery. Under roadmap, a 0.021-inch microcatheter was advanced into the right posterior cerebral artery (PCA). A second 0.0165-inch microcatheter was navigated into the aneurysm. The Barrel device was advanced in the the right PCA and deployed, jailing the coiling microcatheter in the aneurysm. In this particular case, the device could have been deployed on either PCA because the aneurysm location is centered symmetrically. Multiple coils are advanced into the aneurysm to obtain aneurysm obliteration.

Tips, Tricks & Complication Avoidance • The Barrel vascular reconstruction device (VRD) trial is a prospective, multicenter, observational postmarketing registry evaluating the use of the Barrel VRD for treatment of wide-necked bifurcation aneurysms. Nineteen patients with 19 aneurysms were included. Successful aneurysm treatment with a Raymond-Roy occlusion grade of 1 or 2 in the absence of retreatment, parent artery stenosis (> 50%), or target aneurysm rupture at 12 months was achieved in 78.9% of subjects

(15/19; 12 complete occlusions, three neck remnants). One (5.3% ) major stroke at 12 months. (J Neurointerv Surg. 2018;10(10):969–974). • Unlike sidewall aneurysms, complex wide-necked bifurcation aneurysms are difficult to treat endovascularly with simple coiling. Coiling of these aneurysms require stent-assisted coiling in a “Y” or “X” configuration, and the rate of procedure-related permanent neurological deficits is 10% (AJNR Am J Neuroradiol. 2014;35:2153–2158).

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Case Overview

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CASE 28.4 Wide-Necked Basilar Apex Aneurysm: Neck Reconstruction (T-Shaped PulseRider)

• A 68-year-old male was found to have a large intracranial aneurysm during workup for sinusitis. He had significant past medical history of hypertension, diabetes, coronary and peripheral artery disease, atrial fibrillation, and severe COPD. He also had right femoral artery bypass/ stent and recent left hip replacement. He was recently admitted for

treatment of deep venous thrombosis and pulmonary embolism. His current medications included aspirin and coumadin, among others. • Computed tomography (CT) angiography demonstrated a large basilar apex (BA) aneurysm. • The aneurysm was treated with endovascular coiling techniques using a neck reconstruction device.

Fig 28.4a  CT angiogram showing the wide-necked BA aneurysm.

Fig 28.4b  Artist’s illustration of a wide-necked BA aneurysm treated with neck reconstruction device (PulseRider) and coils.

Fig 28.4c  Radial artery access approach.

Fig 28.4d  Wide-necked BA aneurysm.

28  Novel Aneurysm Neck Reconstruction Devices

Fig 28.4e  “T” configuration PulseRider deployment.

Fig 28.4f  Anteroposterior and lateral views of PulseRider devices and coils.

Fig 28.4g  Complete aneurysm obliteration.

Video 28.4  Neck remodeling device-assisted coiling of a large wide-necked basilar apex aneurysm

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Procedure • The patient underwent elective endovascular treatment of wide-necked BA aneurysm with neck reconstruction device (PulseRider) and coiling. Patient continued his antiplatelet and anticoagulation regimen of 325 mg aspirin and coumadin. The procedure was performed under conscious sedation and through a right radial artery approach. 5,000 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Radial artery access. – Micropuncture kit. – 6F Sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch Prowler Select LP ES microcatheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • 3.5 x 10.6 mm Neck Reconstruction Device PulseRider (Cerenovus). • Multiple coils. • 6F AngioSeal percutaneous closure device.

PulseRider is a novel device for the treatment of wide-necked bifurcation aneurysms. It comes in “T” and “Y” shapes. In this particular case, we used a “T”-shaped device because the angle of the two posterior cerebral arteries (PCAs) and the BA is less than 90°. Radial artery access with a 6F sheath was obtained. A guide catheter was advanced into the V3 segment of the right vertebral artery. A 0.021-inch microcatheter over a microwire was advanced into the aneurysm; the microwire is exchanged for the PulseRider. The device was pushed out as the microcatheter is slowly withdrawn; the two limbs of the device were positioned in both PCAs. The device was completely unsheathed for proper anchoring within the BA. A 0.0165-inch microcatheter was advanced through the device into the aneurysm. We advocate that one operator holds the device while a second operator passes the second microcatheter into the aneurysm and deploys coils. Once the aneurysm was completely obliterated and the device was maintained in an adequate position, the device is detached electrolytically.

Tips, Tricks & Complication Avoidance • When planning device deployment, it is helpful to assess the case based on aneurysm, parent artery, and daughter vessels anatomy. • PulseRider is difficult to manipulate and deliver with increased tortuosity. The easiest to deliver is in BA, wherein internal carotid artery bifurcation, middle cerebral artery (MCA), and anterior communicating artery (ACoA) is more challenging. • Configuration of the daughter branch is critical. Besides the angulation for “T”- and “Y”-shaped selection, the symmetric or asymmetric altitude of the branch vessel relative to one another is important. Different altitude presents a real challenge and the device might not be deliverable.

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• It is important for the branches to be coplanar as the device does not flex in the second sagittal plane. This can be very challenging in ACoA and MCA bifurcation aneurysms. • The most challenging type of takeoff vessel angulation is the downward trajectory, most commonly seen in BA and PCA. In these cases, both limbs of the device should be within the aneurysm. Pure intra-aneurysmal deployment has similar concerns to the waffle cone concept, which may divert flow directly into the aneurysm. The device could be deployed intra-aneurysmal and slightly pulled back until it reaches a satisfactory, stable hybrid or extra-aneurysmal position.

28  Novel Aneurysm Neck Reconstruction Devices

Case Overview

CASE 28.5 Basilar Apex Aneurysm: Neck Reconstruction (Y-Shaped PulseRider)

• A 66-year-old female who was found to have an intracranial aneurysm during workup for migraines. She had significant past medical history of hypertension, and coronary artery disease. Her current medications included aspirin and clopidogrel, among others.

• Computed tomography (CT) angiography demonstrated a basilar apex (BA) aneurysm. • The aneurysm was treated with endovascular coiling techniques using a neck reconstruction device.

Fig 28.5a  CT angiogram showing the BA aneurysm.

Fig 28.5b  3D CT angiogram showing the BA aneurysm.

Fig 28.5c  Artist’s illustration of a BA aneurysm treated with neck reconstruction device (“Y”-shaped PulseRider) and coils.

Fig 28.5d  Failed attempt device deployment. The device is asymmetric and tilted, the left PCA is not protected.

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Fig 28.5e  “Y”-shaped PulseRider within the aneurysm.

Fig 28.5f  Initial framing coil.

Fig 28.5g  Progressive coiling.

Fig 28.5h  Complete aneurysm obliteration.

28  Novel Aneurysm Neck Reconstruction Devices

Fig 28.5i  Six-month follow-up. Complete aneurysm obliteration.

Video 28.5  Neck remodeling device-assisted coiling of a wide-necked basilar apex aneurysm

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Procedure • The patient underwent elective endovascular treatment of BA aneurysm with neck reconstruction device (PulseRider) and coiling. Patient continued his antiplatelet regimen of 325 mg aspirin and 75 mg clopidogrel daily. The procedure was performed under general anesthesia and through a right femoral artery approach. 5,000 units of heparin were given to obtain an activating clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.021-inch Prowler Select LP ES microcatheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • 3.5 x 10.6 mm Neck Reconstruction Device PulseRider (Cerenovus). • Multiple coils. • 6F AngioSeal percutaneous closure device.

In this particular case, we used a “Y”-shaped device because the angle of the two posterior cerebral arteries (PCAs) and the BA was more than 90° and the possibility of deploying the device within the aneurysm. A guide catheter was advanced into the V3 segment of the left vertebral artery. A 0.021-inch microcatheter over a microwire was advanced into the aneurysm; the microwire is exchanged for the PulseRider. The device was pushed out as the microcatheter was slowly withdrawn; the two limbs of the device are positioned within the aneurysm. Multiple attempts to position the device limb(s) in the PCAs were done but failed. The device was completely unsheathed for proper anchoring within the BA. A 0.0165-inch microcatheter was advanced through the device into the aneurysm. Once the aneurysm was completely obliterated and the device was maintained in an adequate position, the device was detached electrolytically. As long as the aneurysm neck is protected, device limb(s) can be deployed at parent vessels, aneurysm, or a combination.

Tips, Tricks & Complication Avoidance • PulseRider can be deployed in three configurations: extra-aneurysmal, intra-aneurysmal, or hybrid. There are some benefits for extraaneurysmal configuration. Hybrid or intra-aneurysmal configuration can leave a neck remnant at the corner of the aneurysm above the neck where the arch prevents coils from reaching. • Angulation of the aneurysm relative to the parent vessel is important, as the devices assume no angulation. Some angulation can be tolerated, but straight is ideal. In general, BA and internal carotid artery bifurcations aneurysms are ideal because they have minimalto-no angulation compared to other bifurcations.

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• The device is ideal for superior-projecting aneurysm and much more difficult for anterior or posterior-projecting aneurysms. It is very challenging to obtain optimal neck coverage for non superiorprojecting aneurysms, as the device will always assume a superiorpointing trajectory. The neck coverage may be incomplete of the central zone. • Device sagging can be a problem. We recommend to detach the device after successful coil embolization. With additional coils, the device sags below the true neck of the aneurysm and into the parent vessel. This is improved by applying forward tension on the PulseRider delivery wire while coils are delivered.

29  Aneurysm Embolization with Liquid Embolic Agents Gary B. Rajah and Leonardo Rangel-Castilla

Introduction Liquid embolic agents include nonadhesive Onyx (ethylene vinyl alcohol copolymer (Medtronic), adhesive N-butyl-2-cyanoacrylate (NBCA) (Trufill, DePuy Synthes), and precipitating hydrophobic injectable liquid (PHIL) (MicroVention), which is new to the market. Endovascular aneurysm obliteration with liquid agents is largely reserved for very distal and/or infectious aneurysms. Because of infectious etiologies, mycotic aneurysms arise largely in the distal middle cerebral artery (MCA) and anterior cerebral artery (ACA) territories. Mycotic or infectious aneurysms have a high propensity for rupture and are prone to multiplicity; however, they are usually small in size and can be fusiform. Conventional treatment has consisted of lengthy antibiotic regimens with surveillance via serial computed tomography angiography (CTA) or digital subtraction angiography (DSA) imaging. However, recent studies have shown hemorrhage rates of 60% in patients with mycotic aneurysms, with 57% of these patients having infarcts. Moreover, a study from 2018 reported that only 25% of mycotic aneurysms regressed after antibiotic treatment at a median of 36 days and 36% of mycotic aneurysms enlarged or duplicated. The conclusions of these studies have led authors to suggest surgical or endovascular treatment of these lesions up front, especially when they are > 6 mm. Typically, treatment options are dictated by presentation, with large hemorrhages or surrounding abscesses needing evacuation. Given the friable nature of the vessel wall because of a full mural infection, hybrid approaches can be useful with coil embolization performed in the endovascular suite followed by surgical evacuation of the spaceoccupying lesion. More proximal fusiform lesions will require clip reconstruction versus a trapping and bypass procedure. Because these patients are typically very ill and have usually undergone open heart surgery for valve replacement, endovascular options are very appealing. A meta-analysis of endovascular treatment 86 mycotic aneurysms noted 95.3% occlusion rates, 7.9% recurrence rates, and 5.8% rehemorrhage rates. Good (modified Rankin Scale score < 2) long-term neurological outcomes were noted in 68%, with 12.6% procedure-related morbidity rates. Intranidal aneurysms are another aneurysm still treated by liquid embolic agents. The presence of an intranidal aneurysm greatly increases the risk of arteriovenous malformation (AVM) rupture. One study revealed that 12% of AVMs had intranidal lesions.

Indications Liquid embolic agents are ideal for dealing with aneurysms located in distal noneloquent territories such as those found with mycotic aneurysms of the MCA or ACA territories. In addition, these agents can be used to secure head and neck pseudoaneurysms causing epistaxis or oropharyngeal hemorrhage. Last, liquid embolic agents can be used to secure feeding arterial pedicle aneurysms of AVMs, as well as intranidal aneurysms.

Neuroendovascular Anatomy Because mycotic aneurysms are predominately found in distal cerebral locations that necessitate long reaches with the microcatheter, it is important to assess the patient’s anatomy for tortuosity and stenosis with diagnostic angiography. The presence of a type 3 aortic arch can necessitate alternative access routes. Because these lesions are typically very friable and can circumferentially involve the vessel, soft wires must

be used to decrease the risk of vessel perforation. Eloquent lesions, such as those found in the left-sided opercular vessels (M3 segment of the MCA) or motor area (M4 and M5 MCA segments, can present challenging clinical decisions. Prior to any vessel embolization in these regions, superselective Wada testing with amobarbital (Amytal) and lidocaine or a balloon test occlusion (BTO) should be performed. Distal access catheters (DACs, Stryker) are very useful for these long reaches into the distal cerebral circulation.

Perioperative Medication Systemic heparinization is administered with target activated coagulation time values of 200–250 s. Amobarbital (Amytal) and lidocaine are administered during Wada testing.

Specific Techniques and Key Steps 1. If possible, access is obtained by way of a femoral arteriotomy. A transitional 6 French (F) dilator is utilized once the position of the microwire is deemed appropriate in relation to the femoral head by way of fluoroscopy imaging. A 6–8F femoral sheath is placed depending on biaxial or triaxial needs for vessel tortuosity. 2. The guide catheter with copilot valve is placed in the internal carotid artery or vertebral artery depending on the aneurysm location. 3. Initial digitally subtracted runs are performed in anteroposterior and lateral views (Fig. 29.1-29.4, Video 29.1-29.4). Oblique magnified working views are also obtained; rotational 3D runs can greatly help with this. 4. Given the distal mycotic aneurysm locations, triaxial systems are utilized for more support (Video 29.1-29.4). 5. The microwire–microcatheter assembly can be utilized to help navigate the intermediate catheter to the desired location, typically the A1 segment of the ACA or the M1 segment of the MCA. 6. The intermediate catheter (DAC or Sofia, MicroVention) is advanced into the M2 MCA segment or A2 or A3 ACA segment over the microwire. 7. If Onyx is selected as the embolic agent, a dimethylsulfoxide (DMSO)-compatible microcatheter is advanced as close as possible to the aneurysm (Fig. 29.1-29.4, Video 29.1-29.4). If the lesion is in an eloquent location, a superselective awake Wada test with amobarbital and lidocaine should be performed. Preservative-free lidocaine (30 mg) is injected, followed by amobarbital (75 mg) via the microcatheter. Each medication is injected solely and slowly (30–60 s). A neurological examination is performed to assess for speech or motor deficits. 8. If embolization is desired, DMSO must be injected at a rate of 0.1 mL/minute to fill the microcatheter dead space, followed by Onyx 18 or 34, which is injected at the same rate. A blank roadmap technique should be utilized (Fig 29.1-29.4, Video 29.1-29.4). If using NBCA, the catheter must be removed within seconds after embolization, and the correct viscosity obtained with a mixture of NBCA and lipiodol. A 5% dextrose solution is used to flush the ionic contrast material prior to injecting NBCA. 9. Final runs are taken postembolization. If the Onyx has refluxed and the catheter is stuck, the DAC can sometimes provide countertraction; or a detachable tip microcatheter can be used in these distal locations.

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Device Selection

Pearls

The following are common set-ups and devices used for liquid embolic embolization of distal mycotic aneurysms. • 6–8F sheath. • 90- to100-cm-long 6F guide catheter (Neuron or Neuron MAX 90-cm guide catheter, Penumbra; Envoy, Synthes; or Benchmark 0.071-inch guide catheter, Penumbra). • 0.044- to 0.058-inch intermediate catheter (Sofia, MicroVention; DAC, Navien, Medtronic; Catalyst 5, Stryker). • DMSO-compatible 0.016-inch microcatheter (e.g., Headway Duo, MicroVention; SL-10, Stryker; or detachable tip microcatheter, Apollo, Medtronic). • 0.014-inch microwire (Synchro 2, Stryker). – If BTO is desired (selective), use a 4 × 10 mm Scepter XC balloon catheter (MicroVention) in larger MCA vessels and inject Onyx via the dual-lumen Scepter XC microcatheter, but keep in mind that this product is stiffer than a Headway Duo. – DMSO, sterile 1 mL syringes (Onyx package), and Medallion syringe (Merit Medical) for microinjection or superselective Wada test. – Preservative-free lidocaine and amobarbital. – Onyx 18 or 34. – Continuous heparinized flush.

• If a conservative approach is utilized for mycotic aneurysms, serial CTA or DSA images must be obtained weekly or biweekly to monitor lesion growth. • Coiling, stent coiling, and flow diversion have been described with some success for mycotic aneurysms requiring parent vessel preservation in patients too ill for open cranial repair. However, the use of a stent or flow-diversion device is not the first-line option. • Endovascular therapy is no longer the second option for mycotic aneurysms but represents a valid, safe, first therapeutic option (Fig. 29.1-29.4, Video 29.1-29.4). • After embolization, repeat angiograms (CTA or DSA) are necessary to ensure no recurrence; magnetic resonance imaging (MRI) is also valuable given that mycotic aneurysms can be associated with abscesses and infarcts. Prior to treatment, baseline MRI is obtained to establish whether the targeted area is already infarcted. • If the superselective Wada test is positive, alternative treatment options with vessel preservation should be strongly considered. • The presence of a mycotic aneurysm is not a contraindication for heart valve repair.

29  Aneurysm Embolization with Liquid Embolic Agents

Case Overview

CASE 29.1 Mycotic Middle Cerebral Artery Aneurysm: Liquid Embolic Agent (n-BCA)

• A 60-year-old female with multiple intracranial aneurysms presented with a ruptured pericallosal artery aneurysm that was treated endovascularly. Her hospital stay was complicated with bacteremia and sepsis. Neurologically, the patient recovered completely. After

several weeks in the hospital, a routine computed tomography revealed a new small left middle cerebral artery (MCA) hyperdensity. • Computed tomography (CT) angiogram demonstrated a de novo left MCA aneurysm that was not present on previous imaging.

Fig 29.1a  CT angiogram showing left distal MCA de novo aneurysm (arrow).

Fig 29.1b  Artist’s illustration of a distal mycotic MCA aneurysm treated with n-BCA. Inset, trajectory of the microcatheter distally in the MCA territory.

Fig 29.1c  Angiography demonstrating the distal mycotic MCA aneurysm.

Fig 29.1d  Distal angiography for MCA branch localization.

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Fig 29.1e  Very distal angiography for MCA branch localization.

Fig 29.1f  Complete aneurysm obliteration after n-BCA injection.

Video 29.1  Mycotic MCA aneurysm treated with liquid embolic agent

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Procedure • The patient underwent endovascular treatment of mycotic left distal MCA aneurysm with liquid embolic agent N-butyl cyanoacrylate (n-BCA). The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin were given to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • n-BCA embolic agent. • 6F AngioSeal percutaneous closure device.

All de novo mycotic aneurysms should be treated as they develop fast and are unstable. A 6F guide catheter was navigated into the internal carotid artery and, under road map and magnification, a DMSO-compatible 0.0165-inch microcatheter was advanced into the MCA M2 superior segment. Multiple angiograms through the microcatheter were performed to identify the MCA branch that the aneurysm was originating from. The 0.0165-inch microcatheter could not navigate distal enough to reach the aneurysm directly. The initial plan was to use liquid embolic Onyx; however, because the microcatheter could not be advanced, we changed strategies to liquid embolic n-BCA. The microcatheter was flushed with dextrose solution multiple times to clear from blood products, and n-BCA was then injected to obtain obliteration of the aneurysm and associated arteries. The microcatheter was pulled out quickly to prevent adhesion with the vessel.

Tips, Tricks & Complication Avoidance • Mycotic or infectious aneurysms are small and distally located in the MCA or posterior cerebral artery territory. They can grow or rupture despite antibiotic therapy. The risk of hemorrhage can be as high as 50%, and there is a mortality close to 30% and 80% for unruptured and ruptured aneurysms, respectively. • Liquid embolic agents remain a safe and feasible option in the treatment of intracranial aneurysms. Certainly, they are frequently

used in the management of distal aneurysms in which parent artery embolization is part of the strategy. • n-BCA can easily precipitate when in contact with any minimal amount of blood products. Before n-BCA preparation and injection we recommend a change to new gloves, prepare n-BCA on a different clean surface, and use dextrose solution to purge the microcatheter multiple times prior to n-BCA injection.

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Case Overview

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CASE 29.2 PICA Aneurysm Associated with a Cerebellar AVM: Liquid Embolic Agent (Onyx)

• A 72-year-old female presented to the emergency room complaining of the “worst headache of her life” that started 4 days prior after slipping on ice. In the ER, she started having slurred speech with altered mental status. Eventually, she had to be intubated for airway protection. She was nonfocal, moving all four extremities briskly to pain stimulation. She had a past medical history of hypertension and hypothyroidism.

• Computed tomography (CT) showed intraventricular hemorrhage, and hydrocephalus. CT angiogram demonstrated a cerebellar arteriovenous malformation (AVM) with a flow-related aneurysm originating from posterior inferior cerebellar artery (PICA). • The patient was taken emergently for suboccipital decompressive craniectomy and intraparenchymal hemorrhage evacuation.

Fig 29.2a  Initial CT showing intraventricular hemorrhage and hydrocephalus.

Fig 29.2b  CT angiogram showing the cerebellar AVM and flow-related PICA aneurysm (arrow).

Fig 29.2c  Artist’s illustration of a flow-related PICA aneurysm associated with a cerebellar AVM treated with Onyx.

Fig 29.2d  Angiography demonstrating the flow-related PICA aneurysm associated with a cerebellar AVM.

29  Aneurysm Embolization with Liquid Embolic Agents

Fig 29.2e  Microcatheter at the aneurysm point.

Fig 29.2f  Post Onyx aneurysm embolization angiography showing complete obliteration.

Video 29.2  AVM-associated ruptured aneurysm treated with liquid embolic agent

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Procedure • The patient underwent endovascular treatment of PICA aneurysm with Onyx. The procedure was performed under general anesthesia immediately after the suboccipital decompressive craniectomy and through a right femoral artery approach. Only 3,000 units of heparin were given.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.013-inch Apollo microcatheter (Medtronic). • 0.010-inch Synchro 10 microguidewire (Stryker). • DMSO. • Onyx embolic agent. • 6F AngioSeal percutaneous closure device.

This patient presented with intraventricular hemorrhage. Based on the hematoma pattern (minimal cerebellar hemorrhage and only intraventricular) and the proximity of the aneurysm with the fourth ventricle, the cause of the hemorrhage was attributed to the aneurysms. A guide catheter was positioned at the left vertebral artery and, under road map and magnification, a DMSO-compatible microcatheter was advanced into PICA and aneurysm. The microcatheter was flushed with DMSO slowly and Onyx was injected. Distal parent vessel and aneurysm occlusion was achieved.

Tips, Tricks & Complication Avoidance • Posterior fossa AVMs, specifically, have been shown to be more prone to rupture than supratentorial AVMs. Meta-analysis of patients with posterior fossa AVMs demonstrated 84% risk of hemorrhagic presentation, with subsequent annual rupture rate ranging from 7.5% to 11.6% in the first 5 years. Therefore, timely diagnosis and treatment of infratentorial lesions are imperative. • Feeding artery aneurysms are independent predictors of AVM rupture and subsequent poor outcome, with a 6% attributable risk to hemorrhagic presentation. In some cases, the feeding artery aneurysm

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is the source of the initial bleed, and exceedingly high risk of prenidal aneurysmal rupture has been reported in aneurysms on the PICA feeding artery of posterior fossa AVMs. • We favor endovascular, rather than surgical, treatment for aneurysm related to AVMs. We also favor simple endovascular coiling for aneurysms around the Circle of Willis or proximal vessels and endovascular liquid embolization for aneurysms distal or near the AVM.

29  Aneurysm Embolization with Liquid Embolic Agents

Case Overview

CASE 29.3 Ultra Rapid Formation of Very Distal ACA Mycotic Aneurysm: Liquid Embolic Agent (Onyx)

• A 29-year-old male with active endocarditis underwent computed tomography angiography for mycotic aneurysm screening. He was found to have a right middle cerebral artery (MCA) aneurysm. Diagnostic cerebral angiogram showed slow flow within the MCA aneurysm and was treated with antibiotics. • The patient underwent cardiac surgery to replaced the infected mitral valve. The patient remained neurologically intact until 24 h after surgery when he started complaining of headaches, followed by left mild hemiplegia, and loss of consciousness until he developed left pupil fixed and dilated with no motor movement nor brainstem reflexes. • Computed tomography (CT) showed progressive enlarging right intraparenchymal and intraventricular hemorrhage.

• The patient was taken emergently for right decompressive hemicraniectomy and hemorrhage evacuation. At the time of surgery, the right MCA aneurysm was resected. The hemorrhage was near the initial mycotic aneurysm but no evidence of blood at the immediate surrounding brain parenchyma. • The patient remained stable after surgery. His pupils improved; they were symmetric and reactive. He was localizing on right upper and lower extremities with left hemiparesis. • Repeat CT angiography after surgery showed a new distal anterior cerebral artery (ACA) mycotic aneurysm that was not present 3 days prior on the initial angiography.

Fig 29.3a  Initial cerebral angiography showing right MCA aneurysm. Treated with antibiotics.

Fig 29.3b  Serial CT demonstrating rapidly progressive intracerebral hemorrhage (ICH). Each CT scan was taken 1 h apart. Patient was taken for emergent decompressive surgery.

Fig 29.3c  Postoperative CT angiography demonstrating ultra rapid de novo distal ACA mycotic aneurysm.

Fig 29.3d  Artist’s illustration of a very distal ACA mycotic aneurysm treated with Onyx.

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Fig 29.3e  Angiography demonstrating the very distal ACA aneurysm.

Fig 29.3f  Microcatheter at the aneurysm.

Fig 29.3g  Onyx cast within aneurysm.

Fig 29.3h  Complete aneurysm obliteration.

Fig 29.3i  CT 4 weeks after. Patient had significant recovery.

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29  Aneurysm Embolization with Liquid Embolic Agents Video 29.3  Ultra-rapid mycotic aneurysm formation treated with liquid embolic agent

Procedure • The patient underwent endovascular embolization of very distal ACA aneurysm with Onyx. The procedure was performed under general anesthesia through a right femoral artery approach. 4,000 units of heparin were given.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • DMSO. • Onyx embolic agent. • 6F AngioSeal percutaneous closure device.

Ultra rapid mycotic aneurysm formation and rupture is uncommon. In the current case, once surgical decompression and hematoma evacuation was achieved the patient was taken for endovascular aneurysm occlusion. The second mycotic aneurysm was not found until a repeat CT angiography was obtained after surgery, otherwise surgical resection of the aneurysm could have done at the same time of the hematoma evacuation. A 6F guide catheter was navigated at the internal carotid artery and, under road map, a DMSO-compatible catheter was advanced into the distal ACA and into the aneurysm. DMSO and Onyx were injected to achieve obliteration of the aneurysm. A short segment of the parent artery was also embolized to prevent recurrences.

Tips, Tricks & Complication Avoidance • Treatment of unruptured mycotic aneurysms still debatable, while some people argue to treat medically, others support surgical or endovascular treatment as these aneurysms develop fast and are more fragile than noninfectious aneurysms. We favor the surgical or endovascular treatment of infectious aneurysms. Surgery or endovascular treatment are equally effective. • Endovascular coil or liquid embolic embolization offers a minimal invasive option for patients who might not be hemodynamically

stable because of bacteremia or sepsis. Endovascular treatment is a preferred and effective option as surgical resection/clip ligation. • Very distal infectious aneurysms arise from a small arterial branch that might not accommodate a coiling microcatheter; however, a liquid-embolic microcatheter (e.g., Apollo, Medtronic) can easily be advanced distally to reach small-caliber arteries.

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Case Overview

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CASE 29.4 De Novo Anterior Cerebral Artery Intranidal AVM Aneurysm: n-BCA Embolization

• A 48-year-old female presented to the emergency room (ER) with acute severe progressive headaches. While in the ER, she deteriorated and became lethargic and comatose, requiring intubation. She had a past medical history of large frontal arteriovenous malformation (AVM) that had been embolized multiple times. Her last embolization was 4 weeks prior to her current admission. Multiple stage embolization was planned over a period of several months.

• Computed tomography (CT) showed a large intraparenchymal and intraventricular hemorrhages. • CT angiography showed a de novo formation of intranidal AVM aneurysm that was not present in the last angiography 4 weeks ago.

Fig 29.4a  Initial head CT showing the large intraventricular hemorrhage.

Fig 29.4b  CT angiogram after showing de novo aneurysm formation.

Fig 29.4c  Artist’s illustration of endovascular embolization of de novo intranidal AVM aneurysm with n-BCA.

Fig 29.4d  Grade V AVM previously embolized with de novo intranidal aneurysm.

29  Aneurysm Embolization with Liquid Embolic Agents

Fig 29.4e  Microcatheter injection demonstrating the arterial origin of the intranidal aneurysm.

Fig 29.4f  n-BCA injection into AVM and aneurysm (circle).

Fig 29.4g  Intranidal aneurysms no longer visible.

Video 29.4  De novo formation and ruptured AVM-associated aneurysm treated with liquid embolic agent

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Procedure • After inserting an external ventricular drain to control the intracranial pressure, the patient underwent cerebral angiography and endovascular embolization of intranidal aneurysm. The procedure was performed under general anesthesia through a femoral artery approach. Only 3,000 units of heparin were administered during the procedure.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Envoy XB DA guide catheter (Cook Medical). • Distal Access Catheter 038 (Concentric Medical). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • N-butyl cyanoacrylate (n-BCA) (Medtronic). • 6F AngioSeal percutaneous closure device.

De novo intranidal AVM aneurysm formation is probably the result of hemodynamic changes after previous AVM embolization. All de novo ruptured aneurysms must be treated. A guide catheter was positioned at the internal carotid artery and multiple working projections were performed until adequate visualization of the intranidal aneurysm was obtained. A tortuous branch originated from the anterior cerebral artery (ACA) was found to go directly into the aneurysm. An intermediate catheter was used to reduce microcatheter “sneaking.” Under roadmap, the intermediate catheter was positioned at the ACA and the microcatheter was advanced into the branch leading to the aneurysm. The microcatheter was flushed with dextrose and n-BCA was injected to obliterate a segment of the AVM and aneurysm.

Tips, Tricks & Complication Avoidance • The effect of flow-related aneurysms on hemorrhagic risk of intracranial AVMs was evaluated in a single institution experience. A total of 526 AVMs were identified and only 69 (7.6%) had flowrelated aneurysms. AVMs were more likely located in the cerebellum. Presence of aneurysms increased significantly the risk of presentation with subarachnoid hemorrhage (Neurosurgery. 2018 [Epub ahead of print]).

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• Aneurysms associated with AVMs, are flow related and are found at the Circle of Willis, enlarged AVM arterial feeder, or intranidal. • The majority of the aneurysms associated with AVMs will regress after AVM treatment and rarely need additional procedures. However, if the AVM is untreatable or treatment might take a long time (radiosurgery), management of the aneurysms is recommended. • All ruptured aneurysms associated with AVMs should be treated regardless of AVM management.

30 Endovascular Vasospasm Treatment Gary B. Rajah and Leonardo Rangel-Castilla

General Description

Pharmacological Angioplasty

Cerebral arterial vasospasm secondary to aneurysmal subarachnoid hemorrhage (aSAH) is a common complication of a ruptured aneurysm and can lead to severe infarction or even death. Angiographic vasospasm occurs in 30%–70% of aSAH patients. Symptomatic vasospasm with cerebral ischemia occurs in 20%–30% of aSAH patients. The severity of ischemia correlates with the severity of radiographic vasospasm and the need for early and aggressive endovascular treatment. Transcranial Doppler imaging and computed tomography angiography and computed tomography perfusion (CTP) imaging are noninvasive diagnostic tools that can provide early evidence for ongoing cerebral vasospasm, even before any neurological changes are observed. Medical management of vasospasm should always be utilized in addition to any endovascular treatment.

Pharmacological angioplasty or intra-arterial vasodilator therapy refers to direct intra-arterial delivery of vasodilators, including calcium channel blockers (verapamil, nicardipine, nimodipine) and a phosphodiesterase inhibitor (milrinone). Calcium channel blockers have been the most studied and have indicated the most promise. Among all calcium channel blockers, verapamil is the most commonly used

Indications Endovascular vasospasm treatment is indicated in patients who have either radiographic or symptomatic vasospasm refractory to medical therapy (e.g., the combination of induced hypertension, hypervolemia, and hemodilution [triple-H therapy]). By comparing the percentage of vessel narrowing to that of the initial vessel diameter, we define vasospasm as mild when it is less than 25%, moderate at 50%, and severe when it is more than 75%. The Neurocritical Care Society proposed that invasive management of cerebral vasospasm is indicated in the presence of a new neurological deficit that cannot be completely reversed by maximal medical therapy or when complications associated with medical management become a concern. A literature review made a class IIb recommendation for medical therapy based on level of evidence B according to the American Heart Association guidelines that calcium channel blockers may be beneficial and may be considered for vasospasm refractory to other forms of medical therapy.

Neuroendovascular Anatomy When considering treatment of vasospasm, it is important to have an initial angiogram available for comparison; otherwise, the contralateral side must be utilized for comparison (e.g., initial vessel diameter). The interventionist must be careful interpreting radiographic vasospasm in vascular territories that could be prone to hypoplasia (i.e., anterior cerebral artery [A1 segment], posterior communicating artery, intradural vertebral artery) because treating these vessel segments with a balloon can have devastating consequences. If stent-assisted coiling or flow-diverter device placement is considered for a ruptured aneurysm with vasospasm, caution is advised in conjunction with the infusion of a vasodilator because this can make the sizing of the device incorrect.

Balloon Angioplasty The physiology behind balloon angioplasty effectiveness remains unclear. Dilation of smooth muscle in the contractile state stretches and disrupts connective tissue fibers in the extracellular matrix of the vessel wall and in the smooth muscle.

Perioperative Medications If the patient is awake and not intubated, we usually perform pharmacological and balloon angioplasty without the need for general anesthesia. While the patient is in the neurointensive care unit, intravenous bolus doses of milrinone are administered, typically 8 mg for a duration of 30 min. A milrinone drip can be started intravenously and continued for 14 days in the intensive care unit (ICU), slowly incrementing from 0.5 µg/kg/min to 1.5 µg/kg/min as tolerated.1 Milrinone can cause tachycardia and hypotension. Continuous blood pressure monitoring is essential during the endovascular procedure, given the risk of intraoperative hypotension secondary to vasodilator infusion.

Pharmacological Angioplasty— Specific Technique and Key Steps 1.

2. 3.

4.

5.

Endovascular Angioplasty Alternatives The two endovascular treatment options for vasospasm are pharmacological angioplasty (intra-arterial vasodilator therapy) and balloon angioplasty.

6.

After a femoral angiogram has been performed to confirm the absence of any irregularity or dissection, the diagnostic catheter is placed over a curved wire (0.035-inch angled Glidewire, Terumo), and the system is advanced into the aorta under fluoroscopic guidance. We typically utilize a 6 French (F) femoral sheath in the event that balloon angioplasty is needed. The diagnostic catheter is advanced into the internal carotid artery (ICA) of the symptomatic side and cervical anteroposterior and lateral angiographic runs are obtained. Once roadmaps have been obtained to make sure there is no stenosis or dissection in the neck vessels, the diagnostic catheter is placed just below the skull (C2) segment of the ICA or upper V2 segment of the vertebral artery. An intra-arterial bolus of verapamil (10–20 mg in 10–20 mL of normal saline solution) is slowly infused over a period of 2–4 min. It is important to coordinate with an anesthesiologist because verapamil can cause hypotension and a seizure if injected too fast. Once the verapamil is given, we then move to the next vessel territory (contralateral ICA [contralateral hemisphere] and vertebral artery [posterior circulation territory]). Once all three vessels have been accessed and the symptomatic areas infused, we repeat an angiogram to inspect for improvement.

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V  Intracranial Aneurysms 7. If the symptoms resolve and/or the caliber of the vessels improves, the procedure is then terminated. 8. Patients with severe refractory vasospasm need this procedure every 24 hours or even every 12 hours during the vasospasm period.

Balloon Angioplasty— Specific Technique and Key Steps 1. If focal refractory vasospasm remains, we proceed with balloon angioplasty (Fig. 30.1, Video 30.1). 2. A 6F guide catheter is navigated to the ICA. 3. Balloon selection. A compliant balloon (HyperGlide, Medtronic; Scepter C, MicroVention; Hyperform, Medtronic—too compliant and not very useful, therefore, not recommended), a semicompliant balloon (such as a coronary balloon), or a noncompliant balloon (Gateway balloon, Stryker) can be used. Proper sizing of the balloon is crucial. We recommend undersizing the balloon from 80% to 85% of the baseline normal vessel diameter (e.g., for a 3-mm artery, we would use a 2.5-mm balloon). Balloon length is also important and should be gauged based on the straight length of the spastic segment. 4. The patient is given intravenous heparin (4,000–5,000 units) to reach an activated clotting time (ACT) > 250 seconds. 5. The balloon is properly prepared and navigated over a microwire under magnified roadmap working views to the focal area of stenosis (Fig. 30.1, Video 30.1). 6. Once positioned appropriately, the balloon is slowly inflated with an insufflator to the nominal value (Video 30.1). 7. To inspect the diameter of the vessel and look for any complications (such as vessel perforation), balloon angioplasty can be repeated, and final runs obtained.

Device Selection In our practice, the following are the common set-ups and devices used for pharmacological and balloon angioplasty: • 6F sheath. • 5F diagnostic catheter (Angle, Bio2 Medical or Simmons 2 Glide, Terumo). • 6F guide catheter—only if balloon angioplasty needed. • 0.035-inch angled Glidewire. • HyperGlide, Scepter C, semicompliant coronary balloon, or Gateway intracranial balloon; size 1.5 mm–4 mm.

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• The balloon is prepared with 50:50 contrast: saline ratio utilizing vacuum preparation. • 0.014-inch microwire (Synchro 2, Stryker). – 10–20 mg of verapamil per vessel (ICA, contralateral ICA, and vertebral artery). – Continuous heparinized flush.

Pearls • Symptomatic vasospasm is an emergency, similar to an acute stroke, and should be treated as such. • Inform ICU staff about endovascular vasospasm treatment and the possibility of serial interventions. This will ensure that they do not hesitate to call if endovascular treatment is needed. • Repeated groin punctures can cause trauma to the femoral arteries so we typically alternate sides. Another option is to leave the sheath in place; however, ICU staff must be extremely familiar at managing sheaths. • Slow injection bolus (2–4 min) is important for two reasons. If the injection occurs faster than the recommended time, the pharmacological angioplasty is less effective and it could cause seizures secondary to neuronal irritation from the verapamil. • As with any balloon, improper preparation or non-visualization is very dangerous. Ensure proper setup. If the balloon will not deflate, attach a larger suction syringe to the balloon port. • If vessel rupture is encountered, inflate the balloon for some hemostasis. Be patient and keep checking for extravasation. • Always pay attention to the secured aneurysm. Is it changing or recanalizing? Is the stent migrating on the follow-up vasospasm angiograms? • Balloon angioplasty should be avoided in the vicinity of unsecured aneurysms. • Be aware that if contrast is not visualized while inflating the balloon, blood or air might be in the balloon. This could lead to balloon overinflation and vessel rupture. If this is suspected, the balloon should be purged and prepared again. • Complete deflation of the balloon is imperative before retracting or removing the balloon (Video 30.1). This is confirmed by withdrawing the wire proximal to the proximal balloon marker.

References [1] Fraticelli AT, Cholley BP, Losser MR, Saint Maurice JP, Payen D. Milrinone for the treatment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage. Stroke. 2008;39(3):893–898.

30: Endovascular Vasospasm Treatment

Case Overview

CASE 30.1 Multifocal Severe Vasospasm after Subarachnoid Hemorrhage: TransForm Balloon Catheter

• A 73-year-old female presented with a ruptured basilar apex aneurysm. She originally presented with a Hunt and Hess score of 3. She underwent endovascular coil embolization and external ventricular drain placement for hydrocephalus. • Initial computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) at the basal cisterns and bilateral Sylvian fissures.

• The patient remained stable over the next 5 days; when she stopped following commands, she became lethargic, and had a new onset of left hemiparesis. • Transcranial Dopplers demonstrated increased velocities in all major intracranial vessels. • The patient was taken emergently for diagnostic cerebral angiography for possible intervention.

Fig 30.1a  Initial CT showing diffuse SAH.

Fig 30.1b  Artist’s illustration of a intracranial balloon angioplasty for multifocal vasospasm treatment.

Fig 30.1c  Angiography demonstrating multifocal vasospasm.

Fig 30.1d  Balloon preparation and hand inflation.

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Fig 30.1e  Balloon angioplasty of right MCA.

Fig 30.1f  Balloon angioplasty of right ACA.

Fig 30.1g  Postballoon angioplasty showing significant improvement of vasospasm.

Video 30.1  Balloon angioplasty for severe intracranial vasospasm

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Procedure • The patient underwent cerebral angiography for vasospasm evaluation, pharmacological angioplasty with verapamil, and possible balloon angioplasty. The procedure was performed under general anesthesia through a right femoral artery approach. 4,000 units of heparin were given.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Envoy XB DA guide catheter (Codman). • 3 x 10 mm TransForm balloon catheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Verapamil (30 mg in each internal carotid artery and 20 mg in vertebral artery). • 6F AngioSeal percutaneous closure device.

Symptomatic vasospasm is commonly seen after aneurysmal subarachnoid hemorrhage and most of the time it responds to medical therapy (triple-H). At times, endovascular vasospasm treatment is necessary. Chemical (verapamil) or mechanical (balloon) are the two endovascular angioplasty options. Balloon angioplasty is reserved for severe cases of vasospasm refractory to any medical therapy, as in the current case. The patient had severe vasospasm in multiple territories (bilateral middle cerebral [MCA] and anterior cerebral arteries [ACA]). A 5F diagnostic catheter was advanced into both internal carotid arteries (ICAs) and vertebral artery, 30 mg of Verapamil were injected in each artery, and after a 10-minute wait, minimal vasospasm improvement was noted. A 6F guide catheter was navigated into right ICA and, under road map, a 3 x 10 mm TransForm balloon over a 0.014-inch microwire was advanced and positioned at right MCA stenosis. The balloon was inflated manually and slowly and kept inflated for 20–30 seconds. This procedure was repeated with the contralateral MCA and bilateral ACA.

Tips, Tricks & Complication Avoidance • Cerebral vasospasm and delayed cerebral ischemia remain significant causes of delayed morbidity and mortality in this patient population. Angiographic vasospasm can be found in up to 70% of patients and one-third to one-half experienced neurological symptoms. • Current American Heart Association/American Stroke Association guidelines for the management of post-SAH vasospasm state that angioplasty and/or selective intra-arterial vasodilator therapy is reasonable in patients with symptomatic cerebral vasospasm, particularly those who are not rapidly responding to hypertensive therapy (Class IIa, Level of Evidence B). • Noncompliant and semicompliant balloons for the treatment of cerebral vasospasm are safe and effective. The radial force exerted by noncompliant balloons is greater than the radial force exerted by compliant balloons. Compliant balloons exert lower radial force but

may result in arterial dissection or rupture secondary to variations in the final inflation diameter. • Noncompliant balloon nominal diameter is usually chosen based on the original diameter of the vessel before the development of vasospasm or from measurement of the corresponding contralateral vessel minus 0.5 mm (e.g., 2.5-mm balloon for a vessel diameter measured at 3.0 mm. The balloon is inflated to nominal pressure at a rate of 2-4 per minute. • To prevent balloon migration during inflation, one interventionist holds the balloon in place while a second person slowly inflates the balloon. • Do a meticulous balloon preparation, use 80% contrast and eliminate all air bubbles possible. Inadvertent balloon overinflation, because of poor visualization or air within the balloon, could cause artery dissection or rupture.

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Part VI Brain Arteriovenous Malformations and Fistulas

31 Arteriovenous Malformation Embolization with Onyx

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32 Arteriovenous Embolization with N-butyl-2-cyanoacrylate

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33 Endovascular Embolization of Dural Arteriovenous Fistulas

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34 Spinal Arteriovenous Fistula and Malformation Embolization

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35 Carotid-Cavernous Fistula Embolization 428

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31  Arteriovenous Malformation Embolization with Onyx Gary B. Rajah and Leonardo Rangel-Castilla

Arteriovenous malformations (AVMs) represent an abnormal connection between arterial feeders and veins with an intervening nidus. The treatment of certain AVMs can be challenging. Numerous grading scales have been developed to help the interventionist select which lesions should undergo intervention. The classification most frequently used is the Spetzler–Martin (SM) with supplemental criteria. The postoperative risk of neurological deficit ranges from 8% for SM grades 1–2 lesions and 18% for SM grade 3 lesions to 32% for SM grade 4 lesions. Patients with AVMs can present with headaches, seizures, hemorrhage, or incidentally. The lesions carry a 3%–5% estimated yearly risk of hemorrhage. Deep locations, deep venous drainage only, high-flow lesions, and venous stenosis are among the factors that can increase the risk of rupture. Intranidal and prenidal flow-related aneurysms, especially in the posterior fossa, are prone to rupture and should always be treated. Lifetime hemorrhage risk is often calculated by way of the Ondra et al.1 equation of 105 minus the patient’s age. The use of liquid embolic Onyx (Medtronic) has revolutionized the treatment of AVMs. Onyx is an ethylene vinyl copolymer requiring a dimethylsulfoxide (DMSO) carrier for delivery. It is a nonadhesive polymer that is different than N-butyl-2-cyanoacrylate (n-BCA; glue), which was previously utilized for embolization. Ready-to-use vials of Onyx are available in 6% and 8% concentrations named Onyx 18 and Onyx 34, respectively. (Onyx 500 is no longer available.) Initial studies utilizing Onyx for embolization of AVMs date back to 2001. Since that time, numerous studies have supported the use of Onyx for the occlusion of small AVMs or staged embolization of larger AVMs before surgery or radiation therapy. Onyx embolization can reduce the overall AVM size and the amount of blood lost at the time of surgery. Pedicles not easily accessed at the time of surgery can be embolized with Onyx. Furthermore, because we perform AVM Onyx embolizations in an awake patient, awake superselective intra-arterial Wada testing can be performed with Amytal (amobarbital sodium) and lidocaine prior to pedicle embolization.

in the vessel. Onyx can be injected from arterial pedicles or through a transvenous approach. Frontal lesions will have supply from the anterior cerebral artery and the middle cerebral artery (MCA), depending on how medial they are; they may also receive supply from deep lenticulostriate feeders. Parietal lesions will parasitize MCA vessels and posterior cerebral artery (PCA) vessels, such as the parieto-occipital branch. Temporal lesions can have direct internal carotid artery feeders for more medial lesions or be supplied by direct branches from the MCA and choroidal arteries. Posterior fossa lesions typically receive flow from PCAs, the anterior inferior cerebellar artery, or the posterior inferior cerebellar artery. External carotid artery branches should also be investigated because some AVMs can have a dural fistula-like component. Spinal AVMs can be treated with embolization of radicular feeders; however, in our experience, these AVMs are more responsive to surgical resection. Ventricular and deep lesions recruit choroidal vessels and require great care when planning for interventions. Flow-related aneurysms occur at pedicle branch points and within the nidus. Careful review of oblique angiograms can aid in the diagnosis of nidal aneurysms. Venous drainage is the next step in AVM anatomy assessment, including the presence of deep or superficial draining veins, number and size of draining veins, venous hypertension, cortical venous reflux, and stenosis of draining veins. Attention should be paid to venous outflow obstructions and venous thrombosis because these findings can make the AVM more likely to rupture. AVMs can drain superficially by way of the cortical veins or through deep veins such as the internal cerebral veins, ependymal veins, basal vein of Rosenthal or the pontomesencephalic veins, or the petrosal vein of the posterior fossa. Venous access can be important for the completion of an embolization procedure if some of the arterial pedicles have been “locked out” by Onyx. Last, the compactness of the nidus is important. AVMs with a diffuse nidus are challenging and possibly more suitable to embolization than surgery because some eloquent areas of the brain cannot undergo resection without morbidity. Conversely, AVMs with a compact nidus are ideal for surgery, and if superficial, they may require no embolization at all.

Indications

Periprocedural Medications

The role of Onyx embolization depends on the treatment plan. Embolization can be used as curative therapy for small, nonsurgically accessible AVMs; preoperatively as a precursor to complete curative surgical resection; for targeted therapy to obliterate a source of hemorrhage; as a precursor to radiotherapy; and for palliative embolization to relieve symptoms of high-flow shunting. Onyx embolization can also be utilized for occluding nidal and prenidal aneurysms and to reduce surgical morbidity in patients with coagulation disorders. Studies of Onyx embolization have documented complete obliteration rates in up to 50% of small AVMs and an average 75% reduction in AVM size.2

AVM embolization can be performed under awake (conscious) sedation or general anesthesia. Our preference is awake (conscious) sedation to facilitate a neurological examination and more accurate Wada testing. Systemic heparinization is recommended for the embolization of all unruptured AVMs and for most ruptured ones unless there is an absolute contraindication. Verapamil is kept on hand for catheter-induced vasospasm. Antiseizure medications should also be available. We perform awake superselective Wada tests during all embolization procedures. Once the microcatheter has been navigated into the desired location and its position confirmed with microcatheter angiography, we proceed with infusion of 75 mg of preservative-free Amytal (amobarbital), followed by 30 mg of lidocaine, followed by neurological examination. Amytal and lidocaine are used to inhibit the γ-aminobutyric acid (GABA) receptors in gray matter and the sodium (Na) channels in the white matter, respectively.

General Description

Neuroendovascular Anatomy The angioarchitecture and surrounding anatomy of an AVM have to be studied and understood perfectly before an embolization procedure. A diagnostic cerebral angiogram is mandatory to understand the anatomy and physiology of an AVM. Arterial feeders to AVMs should be carefully distinguished from en passage vessels. When planning an embolization procedure, the length, size, and tortuosity of the feeder arteries are important anatomical considerations, because these will determine how easy or difficult it will be to navigate a microcatheter into the AVM nidus and the amount of Onyx reflux that can be tolerated by the catheter

Specific Technique and Key Steps 1. After obtaining femoral arterial access and performing an angiogram to confirm the absence of any irregularity or dissection, the guide catheter is mounted over a curved wire/diagnostic catheter (0.035inch angled Glidewire, Terumo), and the system is advanced into the aorta under fluoroscopic guidance.

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VI  Brain Arteriovenous Malformations and Fistulas 2. The guide catheter should be placed in the extracranial vessel of choice utilizing roadmap navigation. 3. Once in the large vessel of interest (e.g., ICA), cranial anteroposterior and lateral baseline angiograms with high frame rates per second should be obtained and carefully reviewed for flow dynamics (Fig. 31.1-31.7, Video 31.1-31.7). 4. A microcatheter is navigated over a microwire into the desired arterial feeders or into the AVM nidus, if possible. The goal is to navigate to a pedicle as close as possible to the nidus to limit embolization of normal brain tissue (Fig. 31.1-31.7, Video 31.131.7). If navigating far distally (e.g., beyond the M2 or A2 segments), we recommend utilizing an intermediate catheter for support and stabilization (see Pearls). 5. Superselective angiography via the microcatheter is performed again, followed by awake superselective Wada testing. If no major symptoms are encountered with the physiological testing, the pedicle is deemed safe to embolize. 6. Onyx 18 or 34 is typically used. The embolic agent is drawn up in syringes in aliquots of 1 mL. For more distal penetration, Onyx 18 is utilized because it is less viscous. DMSO is also drawn up in a DMSO-compatible syringe. 7. Before Onyx injection, the microcatheter is purged with DMSO. DMSO-compatible microcatheters must be utilized (Headway DUO, MicroVention; SL 10, Stryker; Apollo, Medtronic) (Video 31.131.7). DMSO can be caustic to cerebral vessels and therefore must be infused at a rate of 0.1 mL/min. Thus, microcatheters typically have 0.3 mL dead space, so the first 0.2 mL of DMSO can be pushed into the catheter in a controlled fashion followed by slow pushing of the last 0.1 mL (Fig. 31.2, 31.4). 8. The Onyx is then connected to the microcatheter in a meniscusto-meniscus fashion (Tuohy valve removed) A timer is set. Onyx is slowly injected at a rate of 0.1 mL/min × 3 min with the last minute of the injection observed under subtracted working views until the tantalum component of the Onyx is visible (remember this is pushing the dead space out of the catheter). 9. The first embolization attempt into the pedicle/nidus is usually the most productive and successful (Video 31.1-31.7). Carefully watch for nidal penetration and unwanted venous or arterial filling or arterial reflux. If unwanted venous embolization occurs, stop immediately! Onyx is injected in a fast, pulsing fashion with the thumb. Some operators will first form a plug of Onyx around the catheter while others will just push distally. Reflux around the catheter must be noted, as this can make removal of the microcatheter difficult. 10. Once satisfied with the pedicle or nidal embolization, remove the microcatheter and perform another angiogram run to ensure no unwanted events and examine the awake patient. 11. These steps can be performed for multiple pedicles. For large lesions (SM III-V), a staged approach with one or two pedicles embolized at a time is often safer than a more extensive embolization during a single session. The microcatheter must be disposed of after each Onyx injection. 12. Once the stopping point has been reached, a final angiogram should be performed and all catheters removed.

Device Selection The following are common setups and devices used for Onyx AVM embolization. • 6–8F sheath. • 90- to 100-cm-long 6F guide catheter. • 0.044–0.058 intermediate catheter (Sofia, MicroVention; DAC, Stryker; Navien, Medtronic; Catalyst 5, Stryker). • 0.035-inch angled Glidewire. • DMSO-compatible 0.016-inch microcatheter (e.g., Headway DUO, SL10, or detachable tip microcatheter, Apollo catheter). • 0.014-inch microwire (Synchro 2, Stryker).

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• DMSO. • Onyx 18 or 34. • Intracranial balloons (Scepter, MicroVention) can be utilized if injecting near a vital vessel. • Continuous heparinized flush.

Pearls • Appropriate patient selection and a complete understanding of the anatomy and physiology of the AVM and the morbidity profile of each treatment strategy are keys for successful AVM treatment. • Endovascular neurosurgeons should know the limitations of the embolization technique and safely try to reduce flow into large AVMs. The remainder of the AVM should be left for microsurgical resection (Fig. 31.3, Video 31.3) or radiosurgery. • Microcatheter entrapment is the most common complication of Onyx embolization. If the microcatheter does not come out easily, it requires very slow continuous tension under fluoroscopy to prevent vessel rupture. If the catheter cannot safely be removed, it can be amputated at the groin or removed in surgery as a last resort. • Recognize the vessel anatomy that predisposes catheter entrapment. In general, the smaller the feeding vessel, the more tortuous the approach; the longer the segment of Onyx reflux, the more difficult it will be to remove the microcatheter. • A particular hazard is allowing reflux to creep back along a curve in the vessel. Reflux should be limited as much as possible to straight segments of the feeding vessel. • We recommend utilizing an intermediate catheter for distal vessel navigation and support because of the risk of the microcatheter becoming wedged in the Onyx. The intermediate catheter can allow countertraction when removing the microcatheter (Fig. 31.7, Video 31.7). • We suggest injection of verapamil through the intermediate or guide catheter to reduce vasospasm induced by mechanical traction of the entrapped vessel and microcatheter. • Venous access can be utilized for AVM access; however, care should be taken not to disrupt the venous pedicle before the AVM is completely obliterated (Fig. 31.6, Video 31.6). • DMSO can also result in vessel injury if it is injected too quickly, so inject slowly. • If a venous pedicle is partially occluded, consider a heparin infusion to avoid thrombosis. • If the microcatheter is stuck in the Onyx, the microcatheter can be cut and the intermediate catheter advanced over the microcatheter for counter traction. Balloons can also be used for countertraction. Snares can be used for removing catheters. • Stentrievers can be used to retrieve unwanted embolized Onyx casts if the casts are in undesirable locations. • Strict blood pressure control and at least an overnight stay in the intensive care unit are essential for patients who undergo AVM embolization procedures. • Do not lose track of how much Onyx has refluxed along the catheter and keep the catheter in the Onyx for less than 35 minutes. Both techniques will help decrease the incidence of stuck microcatheters. • Flow-related aneurysms will often decrease in size once the associated pedicle is embolized; however, we advocate treating any aneurysm associated with an AVM, especially intranidal AVMs. • If increased venous shunting is noted, a final angiogram is imperative because the lesion may be at risk of rupture.

References [1] Ondra SL, Troupp H, George ED, Schwab K. The natural history of symptomatic arteriovenous malformation of the brain: A 24-year follow-up assessment. J Neurosurg. 1990;73(3):387–391. [2] Van Rooij WJ, Sluzewski M, Beute GN. Brain AVM embolization with Onyx. AJNR Am J Neuroradiol. 2007;28(1):172–177.

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Case Overview

CASE 31.1 Grade V Frontal Arteriovenous Malformation: Ophthalmic Artery Embolization

• A 48-year-old female presented with seizures and was found to have a right frontal grade V arteriovenous malformation (AVM). She has no past medical history of significance. Seizure became medically refractory to three different anticonvulsants.

• Because of severe symptomatology, the decision was to treat the AVM with staged embolization in preparation for surgical resection or radiation therapy. • Multiple stage embolization was planed over a period of 6 months.

Fig 31.1a  Initial head computed tomography (CT) angiography showing frontal grade V AVM.

Fig 31.1b  Most recent CT angiogram after several embolizations.

Fig 31.1c  Artist’s illustration of endovascular embolization of frontal grade V AVM through the ophthalmic artery.

Fig 31.1d  Grade V AVM.

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Fig 31.1e  Microcatheter distal in the ophthalmic artery.

Fig 31.1f  Onyx injection.

Fig 31.1g  Further partial flow reduction from ophthalmic artery embolization.

Video 31.1  Grade V frontal AVM embolization–ophthalmic artery approach

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Procedure • The patient underwent cerebral angiography and endovascular embolization of her AVM. The procedure was performed under general anesthesia through a right femoral artery approach. 5,000 units of heparin were administered until an activated clotting time of more than 250 was reached.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Envoy XB DA guide catheter (Cook Medical). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

In general, grade V unruptured AVMs are treated conservatively unless they are symptomatic (seizures, steal phenomenon). This patient had a symptomatic large right frontal lobe AVM and we elected for endovascular treatment in preparation for surgery or radiation. Previous embolization stages were performed through anterior cerebral artery branches. Currently, a stage embolization was planned through ophthalmic artery branches. A 6F guide catheter was navigated at the internal carotid artery. Under roadmap and magnification, a DMSO-compatible 0.0165inch microcatheter was advanced over a 0.014-inch microwire into the ophthalmic artery and into the AVM. The ophthalmic artery had several anastomoses with ethmoidal arteries that supplied the AVM. Prior to Onyx injection, an angiography through the microcatheter was done to confirm the position of the microcatheter past the origin of the central retinal artery. Once confirmed, DMSO and Onyx were injected slowly. Minimal amount of Onyx reflux was tolerated to avoid Onyx embolization into retinal artery.

Tips, Tricks & Complication Avoidance • Preoperative embolization may seriously increase the risk of hemorrhage, normal perfusion pressure breakthrough, and further hemodynamic complications. The risk of these rare but potentially catastrophic complications must be minimized by means of progressive rather than acute vascular occlusion of the AVM. Multistage procedures at different times to really enact a staged embolization. The effects of preoperative embolization may not be durable (more durable with liquid embolic agents) because new feeders may be recruited. Stage embolization should be scheduled no greater than 2–3 weeks apart, followed by surgery or radiation several days after the last embolization.

• Hemodynamic changes after stage embolization occurs and the risk of de novo aneurysm formation and AVM rupture could increase. Do not embolize more than 20%–25% of the AVM at a time if surgery or radiation is not planned soon. • Pure endovascular embolization for curative purposes is unclear. Until now, there is no data to support it and endovascular embolization should be followed by curative procedures (surgery or radiation). • Staged embolization should be reserved for grade III–V AVMs. Grade I or II AVMs can be safely treated with microsurgical resection.

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Case Overview

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CASE 31.2 Grade III Parieto-Occipital AVM

• A 18-year-old male presented with generalized tonic-clonic seizures. He had no past medical history of significance and his neurological examination was normal. Initial computed tomography (CT) demonstrated small subarachnoid hemorrhage at the right occipital lobe.

• Further evaluation with CT angiography and magnetic resonance imaging (MRI) showed a large grade III arteriovenous malformation (AVM) at the right occipital area. CT angiography demonstrated AVM arterial feeders from the posterior cerebral arteries (PCAs), some branches of middle cerebral arteries, and superficial draining veins into the superior sagittal sinus.

Fig 31.2a  CT angiogram showing the large AVM.

Fig 31.2b  Artist’s illustration of endovascular embolization of large parieto-occipital AVM with Onyx.

Fig 31.2c  Grade III AVM embolization.

Fig 31.2d  Microcatheter navigated distally into the right posterior cerebral artery.

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Fig 31.2e  Confirming microcatheter position.

Fig 31.2f  Flushing the microcatheter with DMSO.

Fig 31.2g  Onyx injection.

Fig 31.2h  Further AVM obliteration.

Video 31.2  Grade III occipital AVM embolization

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Procedure • The patient underwent cerebral angiography and partial endovascular embolization of the large AVM. The procedure was performed under conscious sedation through a femoral artery approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

Under conscious sedation, using a 6F guide catheter, the distal vertebral artery was accessed. Angiograms run were performed to identify pedicles feeding the AVM. Under road map and magnification, a 0.017-inch DMSO compatible microcatheter was navigated over a 0.014-inch microwire in the the right PCA. Multiple AVM feeders originated from the PCA. We selected the more distal available one to achieve distal to proximal embolization. If a proximal branch is selected and embolized there is a risk of PCA Onyx reflux, blocking access to distal branches. Angiogram run was obtained through the microcatheter to assess catheter position, evaluate AVM segment soon to be embolized, and its relation with draining veins. DMSO was then slowly injected in a rate of 0.1mL/min to avoid vessel toxicity. Onyx 18 was then slowly injected until 20%–25% of the AVM was obliterated or significant Onyx reflux over the microcatheter tip was observed.

Tips, Tricks & Complication Avoidance • We perform the majority of AVM embolizations with patients under conscious sedation, and this allows us continuous accurate neurological examination during the procedure. All patients undergo supraselective Wada test with Amytal and Lidocaine prior to embolization. • For pediatric patients and adults that do not tolerate conscious sedation, the procedure is performed under general anesthesia and monitoring of somatosensory-evoked potentials and electroencephalography. • All patients are heparinized to an activated coagulation time of 200– 250 seconds throughout the procedure.

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• Use DMSO compatible microcatheter (Headway DUO, Excelsior SL10, Echelon, Marathon, Apollo). • Once the microcatheter is placed in the perinidal position, supraselective angiographic runs are obtained to define the anatomy of the arterial feeders and AVM. We recommend the use of higher frame rates for better AVM visualization. Angiographic runs are reviewed and look for arterial feeders (en passage vessels are differentiated from true arterial feeders), rate of transient contrast through the nidus, and anatomy of the draining vein.

31  Arteriovenous Malformation Embolization with Onyx

Case Overview

CASE 31.3 Cerebellar AVM: Presurgical Embolization

• A 33-year-old male presented to the emergency department with progressive headaches and dizziness. The patient’s neurological examination was normal. The patient did not have any significant past medical history.

• Computed tomography (CT) was normal. CT angiography demonstrated a midline cerebellar arteriovenous malformation (AVM) at the upper part of the vermis. The AVM had arterial feeders from bilateral superior cerebellar arteries (SCAs) and two draining veins into the straight sinus.

Fig 31.3a  Cerebellar AVM.

Fig 31.3b  Artist’s illustration of endovascular embolization of cerebellar AVM with Onyx.

Fig 31.3c  Cerebellar AVM.

Fig 31.3d  Microcatheter navigated distally into the right SCA.

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Fig 31.3e  Accessing the AVM with microcatheter.

Fig 31.3f  Onyx 34 injection.

Fig 31.3g  Partial AVM obliteration (stage 1).

Video 31.3  Grade II cerebellar AVM embolization

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Procedure • The patient underwent cerebral angiography and partial endovascular embolization of the large AVM. The procedure was performed under conscious sedation through a femoral artery approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 34 (Medtronic). • 6F AngioSeal percutaneous closure device.

This is a symptomatic grade II cerebellar AVM with high risk of rupture; preoperative embolization was performed in a single stage. Under conscious sedation, a 6F guide catheter was advanced into the left vertebral artery. Heparin was given to obtain an activated clotting time of more than 250. Under road map and magnification, a 0.017-inch microcatheter was advanced over a 0.014-inch microwire into the right SCA and into the larger arterial feeder supplying the AVM. DMSO and Onyx 34 were slowly injected until a certain amount of reflux was seen over the microcatheter tip. After 45–60 seconds, Onyx is injected again for further AVM embolization until more reflux was noted. A third attempt to inject Onyx after a period of waiting, but immediate reflux was noticed again. The syringe was aspirated and the microcatheter slowly pulled out with gentle traction.

Tips, Tricks & Complication Avoidance • Prior to Onyx injection, the anatomy and timing of appearance of the draining vein must be reviewed carefully to prevent Onyx from propagating into and occluding the draining vein. If a high-flow fistula within the AVM is noticed, coils in the feeding artery are deployed prior to embolysate injection to prevent Onyx embolizing directly into the vein.

• The migration of embolysate should be checked periodically using angiography. Injection is performed under blank fluoroscopic roadmap control. • Onyx is delivered until reflux is noted. Embolization can be halted for up to 2 min and the roadmap refreshed to identify the extent of Onyx migration. The goal is to reestablish antegrade flow of Onyx into the AVM. Pauses allow Onyx to precipitate around the catheter, increasing the chances of antegrade flow.

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Case Overview

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CASE 31.4 Ruptured Grade V Thalamic Arteriovenous Malformation

• A 19-year-old female presented to the emergency department with acute onset of severe headaches, nausea, and vomiting. On neurological examination, she was awake, alert, oriented, talking, and moving all four extremities, with no focal deficits. She did not have any significant past medical history.

• Computed tomography (CT) showed mild intraventricular hemorrhage with no hydrocephalus. • CT angiography demonstrated a large thalamic arteriovenous malformation (AVM) with multiple arterial feeders mostly from bilateral posterior cerebral arteries and a large draining vein draining into the straight sinus.

Fig 31.4a  CT showing the intraventricular hemorrhage.

Fig 31.4b  CT angiography showing the large thalamic AVM.

Fig 31.4c  Artist’s illustration of endovascular embolization of large thalamic AVM.

Fig 31.4d  Large thalamic AVM partially embolized.

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Fig 31.4e  Microcatheter in AVM nidus through right PCA initiating Onyx injection.

Fig 31.4f  Onyx cast after stage 2 embolization.

Fig 31.4g  Near complete AVM obliteration. Patient will require a third embolization.

Video 31.4  Grade V ruptured thalamic AVM embolization

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Procedure • Once the patient was fully recovered from her intraventricular hemorrhage. She underwent multiple staged embolization. All embolizations were performed under general anesthesia and through a femoral artery approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained. Here we present stage 2 embolization.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • ENVOY XB DA guide catheter (Cook Medical). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 and 34 (Medtronic). • 6F AngioSeal percutaneous closure device.

This ruptured large thalamic AVM in a young patient should be treated; further hemorrhages will cause significant morbidity and a high risk of mortality. Under general anesthesia and through a femoral artery approach, a 6F guide catheter was positioned at the V3 segment of the left vertebral artery. Under road map and magnification, a 0.017-inch microcatheter was advanced over a 0.014-inch into the right posterior cerebral artery (PCA). Multiple abnormally enlarged thalamoperforators originated from both PCAs. An arterial feeder originated from the right PCA was selected and the microcatheter was advanced into the AVM nidus. DMSO and Onyx 18 were then injected at a 0.1 mL/min rate. A plug was formed in the thalamoperforator, after some time for plug solidification, Onyx was then pushed into the AVM. Around 35%–40% of the AVM was obliterated in this second stage. A third stage is planned in 2–3 weeks prior to radiation.

Tips, Tricks & Complication Avoidance • Preradiosurgical embolizations are planned and carried out to decrease the size and volume of the AVM for future radiosurgery. Embolization is targeted at dealing with elements of AVMs that are not well treated by radiosurgery, such as aneurysms and arteriovenous fistulas. • The “plug-push” technique is an effective means of embolization if the goal is to embolize large segments of AVM. This technique can be performed with two catheters or one catheter. The one-catheter technique is used in small and tortuous feeding vessels, typically associated with more distal AVMs. • The plug is built by injecting Onyx 34 until it appears at the tip of the catheter; the syringe plunger is stroked sharply to let tiny amounts

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of Onyx emerge out of the catheter. The goal is to build a small plug precisely at the catheter tip. The short, tight plug helps prevent reflux, allowing antegrade Onyx flow. • The length of the plug is left to the interventionist’s judgment. Longer plugs lessen the risk of reflux but make pulling the catheter out at the end of the procedure more difficult. Typically, a 1- or 2-cm plug is sufficient. The size of the feeding artery is also important; large and straighter in course vessels allow for longer plugs while still allowing the catheter to be easily extracted. When accessing a small or tortuous vessel, a smaller plug should be formed to prevent complications while pulling the catheter at the end of the embolization.

31  Arteriovenous Malformation Embolization with Onyx

Case Overview

CASE 31.5 Recurrent Facial Arteriovenous Malformation

• A 29-year-old female had a history of left facial vascular malformation that was treated in another institution several years prior to her current presentation. She presents now with a new onset of tingling and redness on her left face and scalp. She was neurologically intact on examination. She did not have any other significant past medical history.

• Computed tomography (CT) angiogram demonstrated a recurrent enlarged left facial arteriovenous malformation (AVM). • Patient underwent diagnostic cerebral angiogram for further evaluation and embolization.

Fig 31.5a  Left facial hemangioma/AVM.

Fig 31.5b  Artist’s illustration of endovascular embolization of facial AVM.

Fig 31.5c  Microcatheter within the vascular lesion.

Fig 31.5d  Microcatheter angiography collaborating adequate catheter position.

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Fig 31.5e  Initial Onyx plug.

Fig 31.5f  Complete vascular lesion embolization.

Video 31.5  Recurrent facial vascular malformation embolization

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Procedure • The patient underwent cerebral angiography and partial endovascular embolization of the facial vascular malformation. The procedure was performed under general anesthesia through a right femoral artery approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

Recurrent facial AVMs can be difficult to treat because of previous embolization that could have resulted in major arterial feeders occlusion and no longer AVM access. The current case had direct arterial feeders from maxillary, occipital, ascending pharyngeal, lingual, and facial arteries. A 6F guide catheter was advanced into the external carotid artery. Under road map and magnification, a 0.017-inch microcatheter was advanced over a 0.014-inch microwire in the occipital artery. Multiple angiography runs were obtained to understand extent of AVM nidus and draining veins. DMSO and Onyx 18 were slowly injected until complete AVM obliteration was obtained. Significant amounts of Onyx reflux was tolerated into the occipital artery.

Tips, Tricks & Complication Avoidance • Extracranial AVMs are less common but have higher recurrence rate because of external carotid, vertebral, and subclavian arteries branches and collateral that favor AVM regrowth. • Extracranial AVM embolization is technically less challenging compared to intracranial AVMs. Larger amounts of embolysate reflux and more aggressive Onyx injection is allowed with less risk of microcatheter entrapment. However, the presence of anastomosis with intracranial circulation (ethmoidal arteries, angular branch of the facial artery) should always be kept in mind.

• Extracranial AVM should be performed under general anesthesia as the injection of DMSO and Onyx could be excruciatingly painful because of the presence of trigeminal nerve receptors. • Avoid injecting liquid embolic agents in the following arteries: ascending pharyngeal artery (risk of lower cranial nerve palsy), petrosal branch of the middle meningeal artery (risk of facial nerve palsy), ethmoidal arteries (risk of ophthalmic and central retinal artery embolization), and meningohypophyseal trunk (risk of internal carotid artery embolization).

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Case Overview

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CASE 31.6 Thalamic Arteriovenous Malformation: Cardiac Standstill-Assisted Transvenous Embolization

• A 16-year-old female presented with new onset of severe acute headache, vomiting, and left side weakness. On examination she had mild left hemiparesis and upward gaze palsy. Patient did not have any significant past medical history. She was found to have a ruptured posterior thalamic arteriovenous malformation (AVM). The patient did not develop symptomatic hydrocephalus and did not require any cerebrospinal fluid diversion procedure. She recovered completely from her initial hemorrhage.

• Patient underwent diagnostic cerebral angiogram demonstrating a thalamic and midbrain AVM with only one enlarged thalamoperforator arterial feeder from the right posterior cerebral artery (PCA). There was only one large vein draining into the straight sinus. • Partial embolization was done through the large the thalamoperforator arterial feeder.

Fig 31.6a  Computed tomography scan showing intraventricular hemorrhage.

Fig 31.6b  Magnetic resonance imaging showing an arteriovenous malformation at the right posterior thalamus, midbrain, and quadrigeminal cistern.

Fig 31.6c  Initial angiography showing only one arterial feeder.

Fig 31.6d  After initial transarterial embolization, no obvious arterial feeder for further embolization.

31  Arteriovenous Malformation Embolization with Onyx

Fig 31.6e  Artist’s illustration of transvenous embolization of thalamic AVM under cardiac standstill.

Fig 31.6f  Thalamic AVM.

Fig 31.6g  Venous access.

Fig 31.6h  Microcatheter and intermediate catheter navigating through sigmoid, transverse, and straight sinus to reach the draining vein.

Fig 31.6i  Occluding balloon in basilar artery during cardiac standstill and Onyx injection.

Fig 31.6j  Injecting Onyx under cardiac standstill and balloon occlusion (arrow).

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Fig 31.6k  Complete AVM embolization.

Fig 31.6l  6-month follow-up magnetic resonance imaging demonstrating no AVM.

Video 31.6  Cardiac standstill and transvenous brainstem/thalamic AVM embolization

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Procedure • The patient underwent cerebral angiography and endovascular transvenous embolization of thalamic AVM under cardiac standstill with rapid ventricular pacing. The procedure was performed under general anesthesia through a femoral artery and direct left internal jugular vein approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • Benchmark 071 guide catheter (Penumbra). • 0.038-inch Glidewire. • 3 x 7 mm Hyperform Occlusion balloon (Medtronic). • 0.014-inch Synchro 2 microguidewire (Stryker). • 6F AngioSeal percutaneous closure device.

After accessing the right femoral artery and the left internal jugular vein. A guide catheter was advanced at the vertebral artery and an intermediate catheter was advanced into the left sigmoid sinus. An occlusion balloon was positioned at the basilar artery and an detachable tip microcatheter was advanced through the transverse sinus, straight sinus, and vein of Galen into the AVM. Confirmation of microcatheter position was done with a venogram through the microcatheter. The microcatheter was then purged with DMSO and Onyx was pushed into the microcatheter but not in the AVM yet. Using rapid ventricular pacing, the anesthesiologist induced tachycardia (180-200 beats per minute) to decrease cardiac output, at the same time the balloon in the basilar artery was inflated. Onyx was then slowly delivered into the AVM until obliteration was obtained; there was some venous reflux around the microcatheter. The Onyx injection lasted 45 seconds. Once the AVM was completely embolized, the microcatheter was left in situ and cut at the jugular vein.

• Femoral vein access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • 0.058-inch Navien intracranial support catheter (Medtronic). • 0.013-inch Apollo detachable tip microcatheter (Medtronic). • 0.010-inch Synchro 10 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 and 34 (Medtronic).

Tips, Tricks & Complication Avoidance • Defining and understanding the venous anatomy remains crucial to successfully traversing the venous system during the transvenous approach to AVMs. • Transvenous microcatheter navigation presents unique challenges. The fragility of cortical veins unrelated to the AVM pose a greater risk of perforation than transarterial navigation. Control angiograms performed through an arterial microcatheter and guide catheter are essential to providing the roadmap for navigation through the venous system, and superselective injections through the arterial microcatheter allow for better characterization of the nidus and optimal positioning of the venous microcatheter (Neurosurg Focus. 2018;45(1):E13). • Transjugular access using a triaxial system can be used for transvenous AVM embolization. Transjugular access allows a microcatheter that has been entrapped in the embolic cast to be cut at the neck, to avoid induction of a cardiac arrhythmia by a retained microcatheter traversing the heart, as would be the case with transfemoral venous access. Newer microcatheters with detachable tips allow for safer microcatheter removal after embolization, thereby improving the feasibility of transfemoral access for transvenous AVM embolization.

• Onyx laminates along the vessel wall, and is both less adhesive and more cohesive. Because of the rapidity of its polymerization, n-BCA is not suitable for transvenous embolization, as immediate occlusion of the draining vein can be disastrous. The slower polymerization rate and cohesive nature of Onyx allows it to be injected over a period of several minutes to over an hour for a more controlled embolization. In contrast to the transarterial approach, Onyx injection time in the draining vein should be as short as possible to form the initial plug, and the time interval to resume injection is also shorter (approximately 20 seconds) compared to arterial embolizations. Coils may be deployed upstream to the draining vein prior to Onyx injection to limit reflux of the embolysate, premature draining vein occlusion, and pulmonary embolism. • AVMs with single draining veins are often considered more favorable for the transvenous approach, as nidal penetration is more easily achieved. Transvenous approach should also be considered on those AVMs with no clearly defined arterial pedicle, tiny perforating arteries, en passage feeding arteries, inaccessible nidal remnants identifiable by a persistent draining, incomplete microsurgery, or failed stereotactic radiosurgery are also reasonable candidates for transvenous embolization.

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Case Overview

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CASE 31.7 Ruptured Temporal Arteriovenous Malformation Embolization during Pregnancy

• A 35-year-old female presented to the emergency room with acute onset of severe headaches and altered speech at a 18th week of pregnancy. Her neurological examination was normal at the time of evaluation. Magnetic resonance imaging (MRI) demonstrated a ruptured left posterior temporal arteriovenous malformation (AVM).

• Because of the risk of further rupture during pregnancy, the decision was to treat the malformation with surgical resection. However, the patient did not accept the risks of general anesthesia and surgery. Therefore, the patient was taken for endovascular embolization with curative goals.

Fig 31.7a  Initial MRI showed a left temporal hemorrhage.

Fig 31.7b  Initial magnetic resonance angiography demonstrating the left temporal AVM.

Fig 31.7c  Artist’s illustration of embolization of rupture temporal AVM using an intermediate catheter.

Fig 31.7d  Left posterior basal temporal AVM.

31  Arteriovenous Malformation Embolization with Onyx

Fig 31.7e  Guide catheter at the vertebral artery (not showing), intermediate catheter at the basilar artery (red arrow), and microcatheter at the distal PCA (white arrow).

Fig 31.7f  Intermediate (red arrow) and microcatheter (white arrow) advanced more distally.

Fig 31.7g  Onyx injection.

Fig 31.7h  Complete AVM embolization.

Video 31.7  Very distal cerebellar AVM embolization

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Procedure • The patient underwent diagnostic cerebral angiogram and endovascular transarterial embolization of AVM. The procedure was performed under conscious sedation through a femoral artery. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained. The procedure was done with minimal radiation exposure and a cover lead on the abdominal region for fetal protection.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.038-inch distal access catheter (DAC) 136 cm (Stryker). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

Under conscious sedation and through a right femoral access, a 6F guide catheter was accommodated at the V3 segment of the left vertebral artery. Under road map and magnification, a 0.038-inch catheter was advanced at the basilar and a 0.017-inch microcatheter over a 0.014-inch microwire was also advanced at the left posterior cerebral artery (PCA). A second angiography run and road map from the the microcatheter was obtained. The microcatheter was advanced further in the proximity of the AVM; at the same time the intermediate catheter was advanced further into PCA. DMSO and Onyx 18 were slowly injected until complete obliteration of the AVM was obtained. The microcatheter syringe plunger was pulled and gentle traction was applied; we observed significant vessel and Onyx cast movement, and this could result in vessel injury. The intermediate catheter was slightly advanced to give support to the microcatheter and facilitate detachment.

Tips, Tricks & Complication Avoidance • The risk of AVM rupture during pregnancy has been reported to be 2.65%–11.1%. The majority of AVM rupture during the second or third trimester of pregnancy when the blood volume and cardiac output reach their peak. The time of onset of AVM rupture may be related to the hemodynamic and hormonal change. Treatment is strongly recommended once AVM has ruptured.

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• Surgical resection and/or endovascular embolization are relatively safe procedures during pregnancy. Radiation effect on maternal and fetal varied according to their development stage and irradiation dose. The safety threshold of irradiation dose at 15–20 weeks of gestation is 120 mGy. Radiation needed for an AVM embolization or aneurysm embolization is far below the safety threshold dose (Arch Gynecol Obstet. 2003;268:325–328).

32  Arteriovenous Embolization with N-butyl-2-cyanoacrylate Kunal Vakharia, Muhammad Waqas, Michael K. Tso, Adnan H. Siddiqui, and Elad I. Levy

General Description N-butyl-2-cyanoacrylate ([n-BCA]; Trufill, DePuy Synthes) and Onyx (Medtronic) are the only two agents approved by the U.S. Food and Drug Administration for cerebral arteriovenous malformation (AVM) embolization. Theory and practice have demonstrated successful treatment of cerebral AVMs by means of multiple different approaches including transarterial embolization of isolated pedicles to complete obliteration and transvenous approaches. n-BCA is the oldest and most commonly used acrylic embolic agent. This agent polymerizes when it comes in contact with hydroxyl ions in blood. The use of n-BCA has been suggested to allow for easier targeting of lesions that may be distal to the catheter tip as well as allowing experienced neurointerventionists to titrate how far they may be able to inject these flow-directed particles.

Evidence for n-BCA for AVM Embolization • Catheter retention was less common with n-BCA than with Onyx (1.6% vs. 9.3%) in a prospective randomized trial that eventually led to the approval of Onyx for use in AVM embolizations. • In 1995, Wikholm et al.1 demonstrated that n-BCA offers an effective permanent occlusion after injection for cerebral AVMs. • In 2010, Loh and Duckwiler2 demonstrated the use of Onyx leading to > 50% AVM reduction in 96% of cases versus 85% for n-BCA. However there was no statistically significant difference.

Indications n-BCA is nearly always permanently occlusive. When mixing n-BCA, experienced neurointerventionists are able to titrate mixtures of ethiodol and glacial acetic acid to adjust the rate of polymerization. This ability to change the rate of polymerization allows n-BCA to be a versatile agent but also can increase the complication rates associated with administration. Polymerized glue is firmer than other agents and can increase difficulty with catheter removal in situations where there is significant reflux. Utilizing flow-directional microcatheters, n-BCA can be guided into large AVM pedicles. These particles travel a significant distance and force the neurointerventionist to be aware of anastomoses and dangerous arterial connections with normal vasculature. What makes n-BCA such a versatile tool includes its ability to be seen clearly on fluoroscopic imaging when mixed with tantalum powder and the ability for the neurointerventionist to use a push technique to enhance the penetration of n-BCA into a target lesion with simultaneous infusion of a 5% dextrose solution, even if the microcatheter is quite proximal from the target.

Neuroendovascular Anatomy Cerebral AVMs have complex anatomy. To understand the arterial anatomy, anastomotic connections, and the potentially complex venous drainage that can be associated with these lesions, it is critical to complete a full diagnostic cerebral angiogram before planning an embolization procedure. Understanding the arterial bed of the AVM nidus and high-risk features of an AVM, including intranidal aneurysms, plays a role in determining which pedicles require embolization. The Spetzler-Martin grading system highlights important characteristics of AVM anatomy that must always be taken into account, including the eloquence of the region of the brain, deep versus superficial venous

drainage, and the size of the AVM nidus. AVMs may arise from any intracranial arterial branches, including the internal carotid artery through all seven segments. Branches or pedicles may arise from middle cerebral artery, anterior cerebral artery, posterior cerebral artery, and posterior circulation perforators. Isolating each circulation or feeding branch is crucial in planning a staged embolization. Understanding deep venous anatomy and ensuring that this is clear on roadmap imaging prior to embolization is equally important to prevent premature occlusion of the draining vein. Of note, it is very important to have a thorough understanding of contributions from the external carotid artery circulation. There may be arterial pedicles and contributions from the external carotid artery circulation as well as anastomoses that must be considered in the preembolization risk assessment.

Periprocedural Medications Wada testing may be performed in circumstances where there is concern for anastomotic connections or in regions of eloquent cortex. Wada testing with amobarbital (Amytal) and lidocaine is routinely performed at the authors’ institution and can allow for a good functional assessment of a patient prior to embolization. Systemic heparinization is administered during the procedure because of the risk of intraprocedural thrombus formation. A weightbased intravenous bolus of heparin aimed at an activated clotting time (ACT) of 250–300 s may limit thromboembolic complications. Intraprocedural anticoagulation is frequently held in circumstances of acute rupture or if emergent surgical intervention may be needed. If heparin is administered, protamine should be readily available in case urgent reversal of the effects of the heparin is necessary. During the procedure, a glycoprotein IIb/IIIa inhibitor (e.g., eptifibatide) can be used for acute thrombus formation.

Specific Technique and Key Steps 1. A 6 or 8 French (F) sheath is inserted in the femoral artery. 2. After femoral angiography has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a 0.035-inch curved wire into the aorta. This maneuver is completed under fluoroscopic guidance. 3. A complete cerebral angiogram is performed (Fig. 32.1, 32.2, Video 32.1, 32.2). 4. The guide catheter is advanced into the distal portion of the vessel of interest. The guide catheter can be brought over a Select catheter (Penumbra) and 0.035-inch Glidewire (Terumo). 5. Cerebral angiography is performed to obtain a baseline set of images of the intracranial vasculature (Video 32.1, 32.2). 6. Under roadmap guidance, a microwire loaded into a microcatheter system with a tight J curve at the distal end can be used to navigate into the arterial pedicle of an AVM (Video 32.1, 32.2). 7. Microinjections are performed through the microcatheter to confirm positioning in the pedicle and to demonstrate filling of the AVM nidus. 8. A sterile back table is set up that is physically separate from other sterile areas to avoid sodium chloride (NaCl) ions contacting the n-BCA. Gloves and gown should be changed prior to mixing the n-BCA. 9. Glue preparation involves mixing ethiodol (2.1 mL) in a labeled syringe, n-BCA (0.9 mL) in a glue-compatible syringe, and tantalum powder (0.5 g) (Video 32.1, 32.2).

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VI  Brain Arteriovenous Malformations and Fistulas 10. Glacial acetic acid (typically seven drops) is added to change the viscosity and polymerization rate of the solution. a. Rule of thumb: If transit time is < 1 s, at least a 70% glue mixture is used. If transit time is > 2 s, this requires a more dilute concentration closer to 50%. 11. The patient is systemically heparinized with an ACT in the range of 250–300 s in cases without rupture. 12. 5% dextrose is injected through the microcatheter to flush the catheter; and after three to four successive injections, the n-BCA mixture is injected slowly (Video 32.1, 32.2). 13. Under a negative roadmap, the n-BCA mixture is injected into the AVM. The injection is quick, steady, and controlled. The glue column should be continuously moving forward. 14. After the embolization is complete (i.e., n-BCA penetration into the nidus) or there is persistent reflux, aspirate on the attached syringe and remove the microcatheter while aspirating from the guide catheter. 15. Final cerebral angiographic runs are performed, and the guide catheter is removed.

Device Selection In the authors’ and editors’ practice, the following are common set-ups and devices used for n-BCA embolization of cerebral AVMs: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy DA XB catheter, Codman Neuro; Benchmark, Penumbra). • 0.035-inch angled Glidewire. • 5F intermediate diagnostic catheter (Vitek, Cook). • Synchro 2 microwire (Stryker). • Microcatheter or flow-directed microcatheter (Headway DUO, MicroVention; Marathon, Medtronic; Magic, Balt USA; Ultraflow, Medtronic). • Continuous heparinized flush.

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Pearls • In direct arteriovenous fistulous connections, a coil placed in the arterial pedicle prior to embolization can be helpful. • The 5% dextrose push technique can be used to allow for further penetration of n-BCA into a nidus after the n-BCA injection has been stopped. This technique can allow for better distal penetration after the arterial pedicle has been embolized. • At the authors’ institution, embolization of AVMs is staged to avoid harmful effects that can happen from flow related and hemodynamic changes to normal perfusion breakthrough phenomenon (Fig. 32.1, Video 32.1). • Superselective microcatheter injections prior to embolization are crucial to confirming catheter position prior to embolization. A 1 mL syringe affords better contrast injection and depiction of vascular anatomy in high-flow lesions. • Prenidal and intranidal aneurysms may be occluded simultaneously with the AVM after n-BCA injection. • If n-BCA reflux results in microcatheter entrapment, constant gentle pressure is applied to remove the catheter. If it still cannot be removed, the microcatheter can be cut at the right common femoral artery access site, and the patient is subsequently treated with dual antiplatelet agents.

References [1] Wikholm G. Occlusion of cerebral arteriovenous malformation with N-butyl cyanoacrylate is permanent. AJNR Am J Neuroradiol. 1995;16(3):479–482. [2] Loh Y, Duckwiler GR, Onyx Trial Investigators. A prospective, multicenter, randomized trial of Onyx liquid embolic system and N-butyl cyanoacrylate embolization of cerebral arteriovenous malformations. Clinical article. J Neurosurg. 2010;113(4):733–741.

32  Arteriovenous Embolization with N-butyl-2-cyanoacrylate

Case Overview

CASE 32.1 Frontal Arteriovenous Malformation: n-BCA Embolization

• A 70-year-old male presented to the emergency room with acute onset of severe and left-sided leg weakness. On neurological examination, he was awake, alert, oriented to person, time, and place. His motor strength was normal except for left lower extremity mild weakness. He had past medical history of hypertension. • Computed tomography (CT) showed a posterior thalamic hemorrhage with intraventricular extension.

• CT angiography demonstrated a left frontal arteriovenous malformation (AVM). • The thalamic and ventricular hemorrhage were unlikely related to the frontal AVM. The patient was managed conservatively and after he recovered from the hemorrhage, he was scheduled to have endovascular and surgical treatment of the frontal AVM.

Fig 32.1a  Initial CT showing the posteriothalamic and ventricular hemorrhage.

Fig 32.1b  CT angiography demonstrating the left frontal AVM.

Fig 32.1c  Artist’s illustration of embolization of frontal AVM with n-BCA liquid embolic agent.

Fig 32.1d  Left medial frontal AVM.

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Fig 32.1e  Microcatheter injecting n-BCA at the posterior branch of the ACA.

Fig 32.1f  n-BCA injected at the frontal branch of the ACA going into the AVM.

Fig 32.1g  Near complete AVM embolization in preparation for surgery.

Video 32.1  Grade II frontal AVM embolization

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Procedure • The patient underwent an endovascular transarterial embolization of AVM with N-butyl cyanoacrylate (n-BCA). Two different branches of the anterior cerebral artery (ACA) feeding the AVM were identified and targeted. The procedure was performed under conscious sedation through a femoral artery. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • ENVOY XB DA guide catheter (Cook Medical). • 0.017-inch Echelon-10 microcatheter (Medtronic) (2). • 0.014-inch Synchro 2 microguidewire (Stryker). • TRUFILL n-BCA liquid embolic agent (DePuy Synthes). • 6F AngioSeal percutaneous closure device.

Unlikely, the initial thalamic and intraventricular hemorrhage were related to the frontal AVM. The patient was treated conservatively and let him recovered from the hemorrhage. Preoperative embolization was electively scheduled. Under conscious sedation, a 6F guide catheter was positioned at the internal carotid artery. Under road map, a 0.017-inch microcatheter was advanced over a microwire into the ACA. Angiography run was obtained and found two ACA branches going directly into the AVM. The microcatheter was advanced further into the posterior aspect of the AVM; because of vessel tortuosity the AVM could not be reached directly. The initial plan was to inject Onyx; however, because the microcatheter was not advanced near enough to the AVM, n-BCA was used. n-BCA can flow more distally before it precipitates. The microcatheter was flushed with 5% dextrose solution multiple times followed by n-BCA injection and rapid microcatheter removal to prevent adhesion with the vessel. The same procedure was repeated at the anterior AVM branch. Successful partial AVM embolization was obtained prior to surgical resection.

Tips, Tricks & Complication Avoidance • n-BCA preparation: use new gloves and a separate table to avoid ionic substance (blood, saline) contamination. n-BCA is drawn from the vial into a 1-mL syringe. Ethiodol is extracted from the vial and poured into a glass beaker, n-BCA is added and mixed with the syringe plunger. Tantalum powder should be mixed with ethiodol prior to n-BCA addition to obtain a homogeneous opacification mixture. • Glue composition depends on hemodynamics of the targeted lesion. n-BCA ethiodol ratios of 1:2 and 1:4 are the most common. The

viscosity of the embolic mixture increases with the amount of added ethiodol. • Flush the microcatheter with 5% dextrose to prevent early n-BCA polymerization, it floods the target vessel with a nonionic fluid to facilitate penetration. After injecting 5% dextrose, n-BCA should be injected as fast as possible to prevent blood entering the microcatheter.

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Case Overview

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CASE 32.2 Ruptured Frontal Micro-Arteriovenous Malformation: Endovascular Exploration and n-BCA Embolization

• A 65-year-old male presented to the emergency room with acute weakness of the left arm and leg. On neurological examination, he was awake, alert, oriented to person and time, left mild hemiparesis, and left facial droop. He had past medical history of hypertension, diabetes, and hepatitis C.

• Computed tomography (CT) showed a right frontoparietal hemorrhage. • CT angiography was suspicious but not clear for small arteriovenous malformation (AVM).

Fig 32.2a  Initial CT showing right frontal hemorrhage.

Fig 32.2b  CT angiography showing the possible small AVM (arrows).

Fig 32.2c  Artist’s illustration of embolization of ruptured micro-AVM with n-BCA liquid embolic agent.

Fig 32.2d  Right frontal micro-AVM.

32  Arteriovenous Embolization with N-butyl-2-cyanoacrylate

Fig 32.2e  Microcatheter positioned at the arterial feeder of the small AVM.

Fig 32.2f  n-BCA injected.

Fig 32.2g  Complete AVM embolization.

Video 32.2  Curative embolization of a ruptured micro-AVM

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Procedure • The patient underwent endovascular exploration and embolization of micro-AVM with N-butyl cyanoacrylate (nBCA). The procedure was performed under conscious sedation through a femoral artery. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • ENVOY XB DA guide catheter (Cook Medical). • 5F Sofia intermediate catheter (Microvention). • 0.017-inch Echelon-10 microcatheter (Medtronic) (2). • 0.014-inch Synchro 2 microguidewire (Stryker). • TRUFILL n-BCA liquid embolic agent (DePuy Synthes). • 6F AngioSeal percutaneous closure device.

The patient presented with an intraparenchymal hemorrhage from a very small AVM located at the right motor area. Surgical AVM resection with hematoma evacuation could deteriorate his neurological condition and endovascular embolization with no surgery was planned. Finding the arterial feeders of a micro-AVM for embolization could be challenging. A 6F guide catheter was positioned at the right internal carotid artery. Under road map and magnification, the intermediate catheter was positioned at the superior M2 branch and the microcatheter was advanced distal into an M3 branch. Multiple microcatheter angiography runs were obtained to identified AVM feeders. The microcatheter was advanced as distal as possible but could not navigate in close proximity to the AVM; therefore, n-BCA was used. The microcatheter was purged with 5% dextrose and n-BCA was injected quickly followed by brisk microcatheter removal. Postembolization angiography demonstrated complete AVM obliteration.

Tips, Tricks & Complication Avoidance • Eliminate the microcatheter slack accumulated during distal navigation prior to embolization to reduce the risk of microcatheter retention. • Check microcatheter position prior to embolization. Obtain superselective injections with a 3 mL or a 1 mL syringe. Inject contrast slowly to prevent vessel rupture. • Allow minimal reflux (< 5 mm) for intracranial AVM and remove the microcatheter briskly as fast as possible.

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• If surgical resection of the AVM is not planned on the following days, we strongly suggest stage embolizations in 2–3 different sessions. If possible and feasible, do not embolize more than 30% of the lesion at a time. • Develop liquid embolization skills patiently, favoring a conservative approach at first.

33  Endovascular Embolization of Dural Arteriovenous Fistulas Enrico Giordan, Giuseppe Lanzino, and Leonardo Rangel-Castilla

General Description Intracranial dural arteriovenous fistulas (dAVFs) are rare pathological anastomoses between meningeal arteries and dural venous sinuses or dural veins. The fistula is located within the dural leaflets and consists of a direct communication between an artery and a venous sinus or dural veins. dAVFs account for 10%–15% of all intracranial vascular malformations and most frequently affect patients in their fifth to sixth decade of life without a clear sex predilection or genetic susceptibility. Most dAVFs are located at the junction of the transverse and sigmoid sinuses, followed by the cavernous sinus (with a benign natural history), superior sagittal sinus, anterior cranial fossa, tentorium, and other locations. The pathological mechanisms underlying dAVF formation are still debated. The majority of dAVFs are of an acquired nature, from traumatic head injury, infection, previous craniotomy, tumors, or dural venous sinus thrombosis. Also, risk factors for venous thrombosis, such as antithrombin, protein C, and protein S deficiencies, have been associated with dAVFs occurrence. Symptoms are usually related to increased blood flow through a venous sinus or sinuses and are linked to shunt location and venous drainage patterns. Pulsatile tinnitus is a common symptom for transverse and sigmoid sinus lesions, whereas cavernous sinus dAVFs present with ocular symptoms. Severe presentations include intracranial hemorrhage and nonhemorrhagic neurologic deficits, such as seizures, parkinsonism, cerebellar symptoms, apathy, failure to thrive, and cranial nerve abnormalities. Hemorrhagic presentations are more frequent in high-grade dAVFs. Radiologic evaluation includes computed tomography angiography and magnetic resonance imaging. However, all cases must be confirmed with conventional catheter-based angiography, which is the gold standard for detection and classification of dAVFs.

angioarchitecture. In this classification, type I lesions drain antegrade into a dural sinus, and type II lesions drain retrograde into a venous sinus, both without CVD. Type IIb fistulas drain antegrade into a venous sinus and have venous reflux into cortical veins, whereas type IIa fistulas drain retrograde into a dural sinus and have CVD. Type III dAVFs drain directly into cortical veins, and type IV fistulas drain directly into cortical veins and display venous ectasia. Type V fistulas drain exclusively into the spinal perimedullary veins. Borden types II and III fistulas as well as Cognard types IIb through V fistulas are considered high grade and have an aggressive natural history.

Endovascular Approaches Endovascular therapy has become the first line of treatment for most intracranial dAVFs. The aim of treatment is complete obliteration of the arteriovenous shunt. Endovascular treatment can be divided into three main categories: transarterial embolization (TAE), transvenous embolization (TVE), and combined approaches. TAE involves superselective catheterization of arterial feeders. The microcatheter tip should be “wedged” in the feeding artery, and the embolic agent should penetrate the fistulous connection and proximal aspect of the venous recipient. TAE is suggested when a dAVF drains into a parallel channel within a patent dural sinus that is compartmentalized and when the dAVF drains into a venous pouch immediately adjacent to a major patent dural sinus that is not compartmentalized. TVE is performed by retrograde catheterization of the involved dural sinus or cortical vein followed by deposition of coils and/or liquid embolic agents adjacent to the shunt. The aim of endovascular treatment is occlusion of the arteriovenous fistula and/or disconnection of leptomeningeal or cortical reflux with preservation of normal venous drainage.

Indications

Endovascular Agents

Historically, endovascular management was palliative because feeding artery occlusion was followed by recruitment of additional arterial blood supply. Curative embolization can be achieved only when the microcatheter is positioned close enough to the nidus so that the embolic material occludes the fistula as well as the draining vein; this can be achieved transarterially or transvenous route. Liquid embolic agents such as Onyx (Medtronic) and N-butyl-2-cyanoacrylate (n-BCA) have emerged as a safe and effective technique for the management of dAVFs. In general, symptomatic grade I and all grade II-V dAVFs should be considered for treatment.

Available embolic agents include particles, coils, ethanol, n-BCA, and Onyx. Particles should generally be avoided because they often lead to incomplete and impermanent fistula obliteration. Coils can be used as an adjunct to liquid embolic agents in high-flow dAVFs to reduce high flow and prevent Onyx emboli distal into nondesired veins or sinus. Coils are not curative when used alone, whereas n-BCA can promote progressive occlusion of residual flow seen on immediate posttreatment angiography with excellent cure rates. A major advantage of Onyx is its ability to cure complex fistulas through a single pedicle.

Neuroendovascular Anatomy dAVFs are distinguished from parenchymal or pial arteriovenous malformations by the presence of a dural arterial supply and the absence of an interposed parenchymal nidus. The most commonly used classification for dAVFs is the Borden classification. It distinguishes dAVFs based on venous drainage characteristics, especially the absence of cortical venous drainage (CVD). Borden type I fistulas have dural arteries that drain exclusively into a dural sinus with antegrade venous flow. Type II fistulas drain into a dural sinus with venous flow that is both antegrade into the dural sinus and retrograde into cortical veins. Type III fistulas drain exclusively into cortical veins in a retrograde fashion. Another commonly used classification, the Cognard score, is based on shunt location, venous drainage characteristics, and venous outflow

Periprocedural Medications Full heparinization during embolization is essential to prevent thromboembolic complications. The procedure can be performed under conscious sedation but general anesthesia may be necessary if patients do not hold still or experience discomfort or pain during the liquid embolic injection.

Specific Technique and Key Steps 1. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is placed over a curved wire and a diagnostic catheter (0.035-inch angled Glidewire, Terumo), and the catheter system is advanced into the aorta under fluoroscopic guidance.

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VI  Brain Arteriovenous Malformations and Fistulas 2. The guide catheter should be placed in the extracranial (external carotid artery [ECA], common carotid artery or vertebral artery) vessel of choice utilizing roadmap navigation (Fig. 33.1-33.4, Video 33.1-33.4). 3. The use of an intermediate catheter is recommended in cases of moderate to severe ECA tortuosity. The intermediate catheter (Sofia catheter, MicroVention or distal access catheter [DAC], Stryker) is connected to a heparinized flush and introduced through the guide catheter (Video 33.1-33.4). 4. A dimethylsulfoxide (DMSO)-compatible microcatheter (Headway DUO, MicroVention; Excelsior XL-10, Stryker; or Apollo detachable tip, Medtronic) is connected to the heparinized flush and introduced through the intermediate or guide catheter. 5. Optimum working views of the fistula are identified on magnified anteroposterior and lateral fluoroscopy. 6. The microwire and microcatheter are navigated as close as possible to the fistula nidus. For a transverse or sigmoid dAVF, the initial arterial route to approach the fistula nidus is the middle meningeal artery or one of its branches (Fig. 33.2, 33.3, Video 33.2, 33.3). 7. Superselective angiography via the microcatheter is performed to confirm microcatheter location. 8. The Onyx 18 or 34 formulation is typically used. The embolic agent is drawn up in syringes in aliquots of 1 mL. For more distal penetration, Onyx 18 is utilized because it is less viscous. DMSO is also drawn up in a DMSO-compatible syringe. 9. Before the Onyx injection, the microcatheter is purged with DMSO. DMSO can be caustic and therefore must be infused at a rate of 0.1 mL/min. Thus, microcatheters typically have 0.3 mL dead space, so the first 0.2 mL of DMSO can be pushed into the catheter in a controlled fashion followed by slow pushing of the last 0.1 mL. 10. The Onyx is then connected to the microcatheter in a meniscusto-meniscus fashion (Tuohy valve removed). A timer is set. Onyx is slowly injected at a rate of 0.1 mL/min for 3 min with the last minute of the injection observed under subtracted working views until the tantalum component of the Onyx is visible (remember, this is pushing the dead space out of the catheter). 11. The first embolization attempt into the fistula nidus is usually the most productive and successful. Carefully watch for nidal penetration, venous or arterial filling, or arterial reflux. An extracranial Onyx injection can tolerate more arterial reflux than intracranial injections. Filling of the venous pedicle is the goal; however, if the sinus is patent, Onyx injection of the sinus is not desired (Video 33.1-33.4). 12. Once satisfied with the nidal embolization, remove the microcatheter and perform another angiogram run to ensure no unwanted events and examine the awake patient. 13. The above steps can be performed for multiple pedicles. A staged approach with one or two pedicles embolized at a time is often safer than a more extensive embolization during a single session. The microcatheter must be disposed of after each Onyx injection. 14. In a similar fashion, a TVE is performed. A guide catheter is placed at the sigmoid sinus. An intermediate catheter is navigated through the transverse sinus, straight sinus, or superior sagittal sinus. From there, a microcatheter is navigated through the draining vein in to the fistula. DMSO and Onyx are injected in a similar fashion. 15. TVE tolerates less embolic agent reflux, and the interventionist should be aware of this (Fig. 33.4, Video 33.4). 16. Once the stopping point has been reached, a final angiogram should be performed and all catheters removed.

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Device Selection The following are common setups and devices used for Onyx AVM embolization. • 6–8 French (F) sheath. • 90–100 cm long 6F guide catheter. • 0.044-0.058 intermediate catheter (Sofia, Microvention; DAC or Navien, Medtronic; Catalyst 5, Stryker). • 0.035-inch angled Glidewire. • DMSO-compatible 0.016-inch microcatheter (e.g., Headway DUO, MicroVention; SL-10, Stryker) or detachable tip microcatheter (Apollo catheter, Medtronic). • 0.014-inch microwire (Synchro 2, Stryker). • DMSO. • Onyx 18 or 34. • Intracranial balloons (Scepter, MicroVention) can be utilized if injecting near a vital vessel. • Continuous heparinized flush.

Pearls • Appropriate patient selection and a complete understanding of the anatomy and physiology of the fistula and the morbidity profile of each treatment strategy are keys for successful dAVF treatment. • Extracranial vessel microcatheter entrapment carries less risk of vessel rupture than intracranial microcatheter entrapment but nevertheless requires slow continuous and firm tension to remove the microcatheter. • Recognize the vessel anatomy that predisposes catheter entrapment. In general, the smaller the feeding vessel, the more tortuous the approach; the longer the segment of Onyx reflux, the more difficult it will be to remove the microcatheter. • We recommend utilizing an intermediate catheter for distal vessel navigation and support because of the risk of the microcatheter becoming wedged in the Onyx. The intermediate catheter can allow countertraction when removing the microcatheter (Video 33.1-33.4). • Venous access can be utilized for dAVF access; however, care should be taken not to disrupt the venous pedicle before the fistula is completely obliterated (Fig. 33.4, Video 33.4). • A small amount of liquid embolization into the normal venous sinus is generally tolerated. • DMSO can result in vessel injury if it is injected too quickly, so inject it slowly. • Do not lose track of how much Onyx has refluxed along the catheter and keep the catheter in the Onyx for less than 35 minutes. Both techniques will help decrease the incidence of trapped microcatheters. • Do not pause the injection for more than 2 minutes, as this can cause the Onyx to solidify in the catheter. • Neurological injury can occur if embolizate inadvertently occludes normal draining veins or if collaterals between the ECA and internal carotid artery or vertebral arteries are unrecognized. • Avoid using the ascending pharyngeal artery as a conduit to access a dAVF. Embolization of branches of this artery could cause lower cranial nerve neuropathies. • Avoid using the petrosal branch of the middle meningeal artery to access a dAVF. Partial or complete occlusion of this branch could cause facial nerve palsy.

33  Endovascular Embolization of Dural Arteriovenous Fistulas

Case Overview

CASE 33.1 Anterior Skull Base Arteriovenous Fistula: Transarterial and Transvenous Endovascular Approach

• A 49-year-old male presented to the emergency room with acute onset of simple partial seizures. On neurological examination he was awake, alert, oriented to person, time, and place, and was nonfocal. He had a past medical history of hypertension, coronary artery disease, and recent cardiac stent placement. Patient was currently on aspirin and prasugrel.

• Computed tomography (CT) demonstrated right frontal edema and acute hemorrhage was observed. • Magnetic resonance imaging (MRI) showed possible frontal arteriovenous malformation or fistula.

Fig 33.1a  Initial MRI showing right frontal vascular malformation.

Fig 33.1b  Artist’s illustration of transarterial and transvenous embolization of anterior skull base arteriovenous fistula.

Fig 33.1c  Anterior skull base arteriovenous fistula.

Fig 33.1d  Transarterial (ophthalmic artery) microcatheter access into the fistula.

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Fig 33.1e  Transarterial coil embolization.

Fig 33.1f  Transarterial Onyx embolization.

Fig 33.1g  Transvenous (superior sagittal sinus and draining vein) microcatheter access into the fistula.

Fig 33.1h  Onyx cast after transarterial and transvenous embolization.

Fig 33.1i  Complete arteriovenous fistula obliteration.

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33  Endovascular Embolization of Dural Arteriovenous Fistulas Video 33.1  Ethmoidal skull base AVF embolization

Procedure • The patient underwent endovascular embolization of frontal anterior skull base arteriovenous fistula. The embolization was done through a transarterial and transvenous approach. The procedure was performed under general anesthesia through a femoral artery and femoral vein. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple small coils. • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

After obtaining access into the right femoral artery and left femoral vein, a guide catheter was positioned at the left internal carotid artery (ICA). Under road map and magnification, an Onyxcompatible 0.017-inch microcatheter was advanced into the ophthalmic artery (OA) distal to the origin of the central retinal artery and in close proximity to the arteriovenous fistula. After confirming microcatheter position, multiple small coils were deployed followed by DMSO and Onyx. The purpose of the coils was to prevent Onyx reflux back into the OA. Minimal amount of Onyx reflux was tolerated. The microcatheter was removed. ICA angiography showed incomplete fistula obliteration. There was no other arterial access to the fistula; therefore, a transvenous approach was performed. A guide catheter was positioned at the right sigmoid sinus. Under road map and magnification, an intermediate and a 0.013inch microcatheter were advanced into the superior sagittal sinus and fistula draining vein. DMSO and Onyx were slowly injected to obliterate the remaining fistula and draining vein. The intermediate catheter was used for microcatheter support accessing distally into the fistula.

• Femoral vein access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 5F Sofia Intermediate catheter (Microvention). • 0.013-inch Apollo detachable tip microcatheter (Medtronic). • 0.010-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic).

Tips, Tricks & Complication Avoidance • Anterior skull base or ethmoidal arteriovenous fistulas are rare. Traditionally, these fistulas were considered “surgical.” However, in the modern endovascular era, selected patients can be effectively and safely treated with embolization. • To achieve a safe and effective arterial embolization through the ophthalmic artery, position the microcatheter distal to the origin of

the central retinal artery and in close proximity to the fistula. The use of coils to prevent Onyx reflux helps. The goal is to obliterate the fistulous connection with liquid embolic agents. Coils by themselves do not have any effect on the hemodynamics of the fistula. • A transvenous approach to ethmoidal arteriovenous fistula is safe and effective and should always be considered a viable option.

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Case Overview

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CASE 33.2 Dural (Type 3) Arteriovenous Fistula: Conscious Sedation and Transarterial Approach

• A 65-year-old male with 8 months of right temporal and occipital headaches, tinnitus, vertigo, nausea, dizziness, and blurry vision. His neurological examination was normal. He had a past medical history of hypertension. • Computed tomography (CT) showed an extra-axial hyperdensity. • Magnetic resonance (MR) angiography demonstrated a vascular enlargement at the right transverse sinus area and adjacent occipital lobe.

• The patient was diagnosed with dural arteriovenous fistula and underwent endovascular embolization in another institution. The procedure was aborted because of difficult airway and complications during anesthesia and intubation. The patient recovered and sought treatment at our institution.

Fig 33.2a  CT scan showing the right occipital hyperdensity.

Fig 33.2b  MR showing the right occipital extra-axial vascular malformation.

Fig 33.2c  Artist’s illustration of type III dural arteriovenous fistula with Onyx.

Fig 33.2d  Type III dural arteriovenous fistula with significant cortical venous reflux.

33  Endovascular Embolization of Dural Arteriovenous Fistulas

Fig 33.2e  Transarterial MMA microcatheter access into the fistula.

Fig 33.2f  Onyx injection into the fistula.

Fig 33.2g  Complete dural arteriovenous fistula obliteration.

Video 33.2  Type IV dural AVF embolization

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Procedure • The patient underwent endovascular embolization of dural arteriovenous fistula. The procedure was performed under conscious sedation and through a femoral artery approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 6F Sofia intermediate catheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

After obtaining access into the right femoral artery, a guide catheter was positioned at the right external carotid artery. Under road map and magnification, an Onyx-compatible 0.017-inch microcatheter and an intermediate catheter were advanced into the middle meningeal artery (MMA) and internal maxilary artery, respectively. The microcatheter was further advanced distally into the fistula. After confirming microcatheter position, DMSO and Onyx were injected slowly until complete obliteration of the fistula was achieved. We paid careful attention to premature Onyx embolization of the transverse sinus and Onyx arterial reflux, and stopped the injection when necessary. The patient tolerated the procedure well with minimal pain that resolved with standard analgesics. Constant communication with patient was important and facilitated patient cooperation.

Tips, Tricks & Complication Avoidance • Currently, the majority of dural arteriovenous fistulas are treated endovascularly with liquid embolic agents. Good clinical and radiographic outcomes have been reported in more than 90% with minimal fistula recurrence. • The goal of embolization is to obliterate the abnormal fistulous connection including the proximal portion of the draining vein. For transverse/sigmoid fistulas, this can be safely achieved through the MMA. Embolization through the occipital artery (OA) is technically

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difficult because of the tortuosity and lack of support. The OA is surrounded by soft tissue and not bone, compared to MMA. Avoid embolization through the petrous branch of the MMA as it could result in facial nerve palsy. • Preservation of the transverse sinus is important, and if patent, it should be preserved at all cost. • Dural arteriovenous fistula embolization can be performed safe and effectively under conscious sedation.

33  Endovascular Embolization of Dural Arteriovenous Fistulas

Case Overview

CASE 33.3 Recurrent Dural (Type 2) Arteriovenous Fistula

• A 56-year-old male with tinnitus, dizziness, and bilateral whooshing sounds over the last 2 years was referred for possible recurrence of vascular malformation. His neurological examination was normal except for slight decrease in left-sided hearing. He had a past medical history of hypertension and a previous dural arteriovenous (AV)

treated with radiation in another institution. On follow-up, patient was told the fistula was cured. • Computed tomography (CT) was normal. • Magnetic resonance (MR) angiography showed recurrence of dural AV fistula at the left transverse/sigmoid sinus.

Fig 33.3a  MR showing left dural arteriovenous fistula.

Fig 33.3b  Artist’s illustration of type II dural arteriovenous fistula with n-BCA.

Fig 33.3c  Type II dural arteriovenous fistula.

Fig 33.3d  Transarterial (middle meningeal artery) microcatheter access into the fistula.

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Fig 33.3e  Onyx embolization.

Fig 33.3f  Complete dural arteriovenous fistula obliteration.

Video 33.3  Type III dural AVF embolization

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33  Endovascular Embolization of Dural Arteriovenous Fistulas

Procedure • The patient underwent endovascular embolization of dural arteriovenous fistula. The procedure was performed under general anesthesia and through a femoral artery approach. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

After accessing the right femoral artery, a guide catheter was positioned at the left external carotid artery (ECA). Under road map and magnification, an Onyx-compatible 0.017-inch microcatheter was advanced into the middle meningeal artery (MMA). The guide catheter was slightly advanced at the internal maxillary artery. The microcatheter was further advanced distally into the fistula. After confirming microcatheter position, DMSO and Onyx were injected slowly until complete obliteration of the fistula was achieved. We paid careful attention to premature Onyx arterial reflux, and stopped the injection if necessary. The size of the fistula recurrence was small and it took a minimal amount of Onyx to achieve complete obliteration.

Tips, Tricks & Complication Avoidance • The obliteration rate of intracranial dural arteriovenous fistulas in patients treated with stereotactic radiosurgery (SRS) is 63%. Cavernous sinus has a slightly larger obliteration rate of 73% compared to noncavernous sinus 58%.

• SRS should be left as an alternative for those patients that are not candidates for endovascular embolization or surgical disconnection. Patients with cortical venous reflux associated with the dural fistula should not be treated with SRS as they have a high risk of rupture.

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Case Overview

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CASE 33.4 Tentorial Arteriovenous Fistula: Transarterial and Transvenous Approach

• An 80-year-old female with 5-year history of severe right pulsatile tinnitus, vertigo, and decreased hearing on the right side. Her neurological examination was normal and nonfocal, except for moderately decreased hearing on the right side. She had a past medical history of hypertension and atrial fibrillation.

• Computed tomography (CT) was normal. • Magnetic resonance imaging (MRI) demonstrated a possible vascular lesion along the free edge of the tentorium on a prominent large vein in intimate relation with the brainstem.

Fig 33.4a  MRI showing the tentorial arteriovenous (AV) fistula and an enlarged draining vein.

Fig 33.4b  Artist’s illustration of transarterial and transvenous approach to a tentorial AV fistula with Onyx.

Fig 33.4c  Tentorial AV fistula.

Fig 33.4d  Transarterial MMA microcatheter access into the fistula.

33  Endovascular Embolization of Dural Arteriovenous Fistulas

Fig 33.4e  Evidence of residual after transarterial Onyx injection.

Fig 33.4f  Transvenous approach to the fistula.

Fig 33.4g  Complete tentorial AV fistula obliteration.

Fig 33.4h  6-month follow-up MRI showing complete obliteration of the fistula and large draining vein.

Video 33.4  Large tentorial AVF embolization

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Procedure • The patient underwent endovascular embolization of tentorial AV fistula. The procedure was performed under general anesthesia and through the right femoral artery and left femoral vein. 4,500 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Transarterial approach. – Femoral artery access. • Micropuncture kit. • 6F sheath. – 0.035-inch Glidewire. – Benchmark 071 guide catheter (Penumbra). – 5F Sofia reperfusion catheter (Microvention). – 0.017-inch Headway DUO microcatheter (Microvention). – 0.014-inch Synchro 2 microguidewire (Stryker) – Dimethyl sulfoxide (DMSO) (Medtronic). – Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). – 6F AngioSeal percutaneous closure device.

A 071 guide catheter was positioned at the right external carotid artery; under road map and magnification, a 0.017-inch microcatheter was advanced over a microwire into the superior branch of the middle meningeal artery (MMA) until the fistulous portion of the AV fistula was reached. An intermediate catheter was positioned at the foramen spinosum for microcatheter support. Angiography run was obtained through the microcatheter to confirm location. Onyx 18 was injected to obliterate the fistula and other arterial feeders (occipital artery branches). PostOnyx injection angiogram revealed fistula residual and further embolization was needed. The inferior MMA branch (only arterial feeder left for fistula access) was not accessed after multiple attempts. A 088 guide catheter was positioned at the left jugular vein. Under road map and magnification, an intermediate catheter was positioned at the straight sinus and torcula junction. A 0.017 microcatheter over a microwire was advanced into the vein of Galen, vein of Rosenthal, and into the fistula. Onyx 18 was injected to obliterate the remaining of the fistula until some Onyx reflux was observed into the vein of Rosenthal. Final angiography runs demonstrated complete fistula obliteration.

• Transvenous approach. – Femoral vein access. • Micropuncture kit. • 8F sheath. – Neuron MAX 088 guide catheter (Penumbra). – 5F Sofia reperfusion catheter (Microvention). – 0.017-inch Headway DUO microcatheter (Microvention). – 0.014-inch Synchro 2 microguidewire (Stryker). – Dimethyl sulfoxide (DMSO) (Medtronic). – Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic).

Tips, Tricks & Complication Avoidance • Medial tentorial AV fistulas are considered the most complex dural AV fistulas because their location and extensive vascular supply. They constitute only 4%–8% of all dural fistulas. • Endovascular treatment can be performed by transarterial or transvenous approaches, or a combination of both. The MMA remains the most used conduit to reach dural fistulas because of its straight course with no tortuosity, and its long course allows for more Onyx reflux tolerance.

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• Transvenous tentorial dural AV fistula embolization is an adequate option in case a transarterial approach did not achieve complete obliteration. The use of an intermediate catheter is strongly recommended to support microcatheter navigation within tortuous veins. Ideally, the microcatheter should be positioned at the proximal portion of the draining vein.

34  Spinal Arteriovenous Fistula and Malformation Embolization Kunal Vakharia, Muhammad Waqas, Elad I. Levy, and Adnan H. Siddiqui

General Description Spinal vascular malformations, including arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs), are rare lesions that are believed to account for 10% of all spinal cord lesions. Symptoms tend to present after a spontaneous hemorrhage or in a more progressive slow fashion, resulting in spinal cord dysfunction. The natural history of these lesions tends to be that 10% hemorrhage, 19% lead to progressive motor weakness within 6 months of diagnosis, and 71% have a slower progression over time. Understanding the angioarchitecture of these lesions becomes paramount to understanding high-risk characteristics for treatment planning, patient selection, and risk assessment. The etiology of symptom progression tends to focus around intramedullary hemorrhage, arterial steal caused by high-flow lesions, venous hypertension likely from dural arteriovenous fistulas (dAVFs), and mass effect.

Evidence for Treatment • Endovascular treatment for dAVFs leads to gait improvement in 80% of moderately disabled patients and 65% of severely disabled patients. • Intradural perimedullary fistulas are classified based on Merland’s initial description. Type 1 lesions tend to be surgically accessible and high risk for endovascular therapy. Type 2 lesions, located on the dorsal surface of the spinal cord, can be effectively embolized. Type 3 lesions are high-flow dilated vessels likely needing presurgical endovascular therapy. Antonietti et al reported improvement in symptoms for patients after embolization in 26% of type 1 lesions, 27% of type 2 lesions, and 62% of type 3 lesions. • 38 of 47 intramedullary AVMs were treated with N-butyl-2cyanoacrylate (n-BCA), resulting in obliteration of the lesion in 53% with an overall complication rate of 11%.

Classification and Indications Rosenblum et al1 classified AVMs into four types. Type 1 lesions are dAVFs. These lesions can be cured by focusing on achieving successful embolization distal to the arterial-to-venous connection. An embolic plug placed endovascularly in the venous channel significantly improves patient outcomes and decreases risk of hemorrhage and venous hypertension. Type 2 lesions are intramedullary spinal AVMs that are potentially resectable. Angioarchitecture plays a critical role in understanding the indications for treatment. Focused embolization for high-risk features such as intranidal aneurysms can decrease the risk of subsequent hemorrhage and clinical deterioration as well as serve as a preoperative adjunct. Type 3 lesions are juvenile AVMs that have not been associated with high rates of complete obliteration postoperatively. Indications for treatment include high-risk features that require embolization for palliation of symptoms. Type 4 lesions are perimedullary AVFs without an intervening nidus. Several small series have demonstrated successful embolization of these lesions through a transarterial route.

Neuroendovascular Anatomy Spinal vascular malformations typically arise from segmental vessels off the aorta. An understanding of the origin of the artery of Adamkiewicz

as well as the typical vascular loop noted at the conus and higher cervical and subclavian branches that anastomose at the level of the spine is important to appreciate the angioarchitecture of a spinal vascular malformation. Lesions in the spinal cord tend to arise 1 or more vertebral segments from the nidus. They are usually supplied by anterior and posterolateral radiculomedullary arteries with high-flow–lowresistance shunts. Fistulous components and dAVFs occur primarily in the lower thoracic and upper lumbar spine. These malformations consist of a small collection of dural vessels draining into a single intradural vein. They are supplied most often from radicular artery branches, smaller segmental branches, and/or meningoradicular branches. An understanding of the anatomy of perimedullary venous drainage is important. Radiculomedullary venous drainage with retrograde flow into the spinal perimedullary veins must be appreciated. Hairpin loops of vessels typically originate below the pedicle of the vertebra and can lead to malformations several segmental levels away.

Specific Technique and Key Steps (Video 34.1, Video 34.2, Video 34.3) Spinal angiography can be challenging and determining the angioarchitecture of these lesions before approaching them can be even more daunting. A step-by-step method to diagnose the lesion, find major spinal cord arterial pedicles (also referred to as “feeding” pedicles or feeders), and develop a plan for embolization is important. Key steps are as follows (Fig. 34.1-34.3, Video 34.1-34.3): 1. A 6 French (F) sheath is placed into the right common femoral artery. 2. Either a reverse curve-shaped guide catheter (such as a Simmons 1) is navigated directly into the aorta and used to select the segmental vessels of choice or a diagnostic spinal catheter such as a Mikaelson (Soft-Vu) or Cobra (Cook) catheter is used to identify the correct pedicle and a 0.035-inch Glidewire (Terumo) is used to exchange out the diagnostic catheter for a 5F or 6F guide catheter system. 3. The guide catheter is left at the ostia of the segmental vessel and a microcatheter placed over a microwire (Headway DUO, MicroVention over a Synchro 2, Stryker) microwire is advanced into the segmental vessel (Fig. 34.1-34.3, Video 34.1-34.3). 4. Microcatheter runs are performed to help guide treatment and define the angioarchitecture of the lesion. 5. Under roadmap guidance, the microcatheter is navigated distally. 6. An intermediate catheter may be required to provide support to the microcatheter delivery in robust segmental arteries (Distal Access Catheter, Stryker). 7. Wada provocative testing can potentially be helpful in identifying vascular territories that provide en passant vessels or supply the spinal cord. 8. Identification of the artery of Adamkiewicz is crucial to avoiding spinal cord vascular injury. 9. Onyx (Medtronic) or small particles of n-BCA (Trufill, DePuy Synthes) can be used for embolization, depending on the flow rate as well as the size of the pedicle and distal nidus (Fig. 34.1-34.3, Video 34.1-34.3). 10. Postembolization runs are performed through the guide catheter to confirm obliteration of the vascular malformation. 11. The guide catheter is removed from the ostia of the segmental vessel.

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Device Selection In the authors’ and editors’ practice, the following are common setups and devices used for spinal angiography proceeded by endovascular embolization: • 5 or 6F sheath. • 6F guide catheter or 5F multipurpose access catheter (Cordis) after selection with a Mikaelson or Cobra catheter. • 0.035-inch angled Glidewire. • Intermediate catheter in robust segmental arteries (e.g., distal access catheter). • Synchro 2 or Synchro 10 microwire (Stryker). • Marathon (Medtronic) or Headway DUO microcatheters. • n-BCA for smaller particle embolizations (Fig. 34.1, Video 34.1). • Onyx 18 or 34 (Fig. 34.2, Video 34.2). • Coils (Fig. 34.3, Video 34.3).

Pearls • In patients with dAVFs, the feeder and anterior and posterior spinal arteries, including the artery of Adamkiewicz, arise from the same segmental artery. Therefore, identification and navigation into the correct feeder and navigation into the distal vessel becomes paramount to avoid occlusion of a vessel supplying normal spinal cord. • Embolization with n-BCA has shown a 55% rate of improvement in gait for patients with dAVF and a 15% recanalization rate. Onyx can be used depending on the anatomy of the lesion.

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• Coils placed distally can be used to prevent embolization of muscular branches, primarily for the patient’s comfort (Fig. 34.2, Video 34.2). • Slow, small particle embolization of intramedullary lesions with provocative testing helps in achieving a safe embolization. Serial pressure measurements from the microcatheter can indicate when to stop embolization when pressures exceed 90%; however, these measurements are not obtained routinely. • Electrophysiological monitoring for intramedullary lesions with somatosensory-evoked potentials and motor-evoked potentials during general anesthesia is very helpful, especially when navigating the convoluted angiographic anatomy of the spine. • Frequent “puffing” of contrast material from the guide catheter during the embolization procedure, even while navigating the microcatheter, can help ensure that the guide catheter has maintained purchase in the segmental vessel ostia. • To help maintain guide catheter position at the ostia of the segmental vessel, a buddy wire (a second 0.014-inch microwire that provides additional support to the system) can be used to allow the catheter to stay in place during micronavigation.

Reference [1] Rosenblum B, Oldfield EH, Doppman JL, Di Chiro G. Spinal arteriovenous malformations: A comparison of dural arteriovenous fistulas and intradural AVMs in 81 patients. J Neurosurg. 1987;67(6):795–802.

34  Spinal Arteriovenous Fistula and Malformation Embolization

Case Overview

CASE 34.1 Perimedullary Spinal Arteriovenous Fistula Type IV

• A 44-year-old female with no significant past medical history presented with subacute onset of numbness, tingling, and painful burning dysesthesias in the left lower extremity.

• A magnetic resonance imaging of the lumbar spine suggested possible vascular malformation within the canal. • A decision was made to explore the lesion with spinal angiogram and treat with liquid embolization after the Wada test.

Fig 34.1a  Perimedullary spinal arteriovenous fistula.

Fig 34.1b  Artist’s illustration of thoracic arteriovenous malformation/fistula embolization with n-BCA.

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Fig 34.1c  Spinal perimedullary arteriovenous malformation/fistula.

Fig 34.1d  Microcatheter advanced into the vascular malformation.

Fig 34.1e  n-BCA injection.

Fig 34.1f  Complete fistula obliteration. No evidence of early venous drainage.

34  Spinal Arteriovenous Fistula and Malformation Embolization Video 34.1  Type IV spinal AVM embolization

Procedure • The patient underwent endovascular embolization of perimedullary spinal arteriovenous fistula. The procedure was performed under conscious sedation and through the right femoral artery. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained. Spinal Wada test was done prior to embolization.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Cobra spinal guide catheter (Cook). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple coils. • TruFill Liquid Embolic system (Codman). • 6F AngioSeal percutaneous closure device.

Under conscious sedation, a complete diagnostic spinal angiogram was obtained to assess all possible arterial feeders related to the fistula. There was only one midthoracic artery feeding the entire vascular malformation. The vascular malformation is a low flow fistula with a diffuse nidus extending along the dorsal surface of the thoracic spinal cord. The diagnostic catheter was advanced into the thoracic artery and, under road map and magnification, a microcatheter was advanced at the fistula. A spinal Wada test was done using amytal and lidocaine. The patient remained neurologically intact throughout the procedure. After purging the microcatheter with dextrose 5% solution, n-BCA was injected and the microcatheter was removed quickly. Postembolization angiography runs demonstrated complete vascular malformation.

Tips, Tricks & Complication Avoidance • Endovascular techniques offer a minimally invasive alternative to surgery. If feeding vessels are easily accessible, spinal dural arteriovenous fistulas (SDAVFs) can be embolized with liquid embolic agents. However, it may not always be a reasonable option, especially if feeding vessels of SDAVF are difficult to access. For high-flow fistulae, preoperative embolization is a reasonable choice and should be considered. Endovascular treatment may be attempted when the feeders are accessible and can be reasonably embolized. We believe Wada testing is critical to minimize inadvertent embolization of spinal cord tissue. If catheter stability cannot be achieved or if patients fail

Wada testing (despite multiple catheter positions), embolization is aborted and surgical options are employed. • For pial fistulas, attempted embolization should be carried out only via appropriately capacious feeding vessels to mitigate the risk of spasm or vessel injury. Before embolization, the microcatheter position should be carefully scrutinized and reflux minimally tolerated. Superselective amobarbital injection is used by some neurosurgeons before embolization. Again, penetration of the draining vein is crucial for an effective therapeutic occlusion.

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Case Overview

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CASE 34.2 Lumbar Epidural Arteriovenous Fistula

• A 64-year-old male presented with a 6-month history of progressive lower extremities radiculopathy with associated numbness and weakness. He also complained of loss of sphincter control and sexual dysfunction. He had a past medical history of hypertension and a previous lumbar microdiskectomy 14 years prior to his current presentation. Surgery was complicated with infection (diskitis) that required long-term antibiotics.

• On examination, the patient was in a wheelchair, not able to ambulate, with decreased motor strength and sensation on both lower extremities and decreased reflexes. • Magnetic resonance imaging (MRI) from 18 years ago showed an L4-5 disk herniation but no evidence of abnormal vessels. • Current MRI demonstrated severe spinal cord edema, multiple subarachnoid spaces vessels, and a large epidural vessel causing mass effect on the lumbar and thoracic thecal sac.

Fig 34.2a  Initial lumbar MRI showing the L4-5 disk herniation. No evidence of abnormal vessels or spinal cord edema.

Fig 34.2b  Lumbar MRI several years after showing abnormal vessels, spinal cord edema, and large epidural vein (arrows).

Fig 34.2c  Artist’s illustration of lumbar epidural AV fistula embolization with coils and Onyx.

Fig 34.2d  Right lumbar artery injection showing the one single-channel epidural AV fistula and epidural vein in the late venous phase (arrows).

34  Spinal Arteriovenous Fistula and Malformation Embolization

Fig 34.2e  One single-channel epidural AV fistula.

Fig 34.2f  Coil and Onyx embolization.

Fig 34.2g  Complete fistula obliteration. No evidence of early venous drainage.

Fig 34.2h  Normal spinal MRI at 3-month follow-up.

Video 34.2  High-flow spinal epidural AVF embolization

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Procedure • The patient underwent endovascular embolization of epidural lumbar arteriovenous (AV) fistula. The procedure was performed under conscious sedation and through the right femoral artery and left femoral vein. 5,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.035-inch Glidewire. • Cobra spinal guide catheter (Cook). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple coils. • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

After obtaining access into the right femoral artery, a guide catheter was positioned at the right external carotid artery. Under road map and magnification, an Onyx-compatible 0.017-inch microcatheter and an intermediate catheter were advanced into the middle meningeal artery (MMA) and internal maxilary artery, respectively. The microcatheter was further advanced distally into the fistula. After confirming microcatheter position, DMSO and Onyx were injected slowly until complete obliteration of the fistula was achieved. We paid careful attention to premature Onyx embolization of the transverse sinus and Onyx arterial reflux, and stopped the injection if necessary. The patient tolerated the procedure well with minimal pain that resolved with standard analgesics. Constant communication with patient was important and facilitated patient cooperation.

Tips, Tricks & Complication Avoidance • Spinal epidural AV fistulas are uncommon vascular lesions. They have been classified in type A, B1, and B2 based on the degree of thecal sac compression and the presence of intradural draining veins. The current fistula is a type A causing severe thecal sac and spinal cord compression with an intradural draining vein component causing spinal cord edema (J Neurosurg Spine. 2011;15(5):541–549). • Similar to dural intracranial and dural spinal fistulas, the treatment of epidural spinal fistulas involves disconnection of the fistulous segment either by endovascular or microsurgical means. In a recent meta-

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analysis including 125 patients, 67.5%, 23.6%, and 8.95% were treated with endovascular, microsurgical, or both modalities, respectively. Complete obliteration was 83.5% and did not differ between groups (J Neurointerv Surg. 2019;11(1):95–98). • If the fistula has a high flow component, we strongly recommend the use of coils to reduce flow follow by liquid embolic agent embolization if needed. The high flow could inadvertently embolize liquid embolic material to normal spinal cord vasculature.

34  Spinal Arteriovenous Fistula and Malformation Embolization

Case Overview

CASE 34.3 Large Thoracic Arteriovenous Fistula in a Pediatric Patient with Hereditary Hemorrhagic Telangiectasia

• A 3-month-old baby boy presented with a 10-day history of progressive bilateral lower extremity weakness. The patient and his father have hereditary hemorrhagic telangectasia. On examination, he had bilaterally decreased motor strength and hyperreflexia.

• Magnetic resonance imaging (MRI) demonstrated a large thoracic ventral arteriovenous fistula with spinal cord compression and edema and enlarged draining vein.

Fig 34.3a  Thoracic MRI showing large ventral arteriovenous fistula, spinal cord compression and edema, and enlarged draining veins.

Fig 34.3b  Artist’s illustration of large thoracic arteriovenous fistula embolization with coils.

Fig 34.3c  Large thoracic arteriovenous fistula.

Fig 34.3d  Left thoracic radicular artery traveling up over the spinal cord and down to feed the fistula.

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Fig 34.3e  Angle guide catheter and microcatheter.

Fig 34.3f  Coils.

Fig 34.3g  Complete fistula obliteration. No evidence of early venous drainage. Both spinal arteries are patent (arrows).

Fig 34.3h  Normal spinal MRI at 3-month follow-up.

34  Spinal Arteriovenous Fistula and Malformation Embolization Video 34.3  Pediatric large thoracic AVF embolization

Procedure • The patient underwent endovascular embolization of thoracic arteriovenous fistula. The procedure was performed under general anesthesia and through the right femoral artery. 1,000 units of heparin were administered during the procedure until an activated clotting time of more than 250 was obtained.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 4F sheath. • 0.035-inch Glidewire. • Cobra spinal guide catheter (Cook). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple coils.

After accessing the right femoral artery under ultrasound guidance, a complete spinal angiogram was performed to assess all branches of the aorta involved in the fistula. There were only two midthoracic arterial branches joining at the midline to form a single enlarged artery supplying the fistula. Also, from the two enlarged arteries, the artery of Adamkiewicz arises to supply the spinal cord. The Cobra diagnostic catheter was engaged at the ostium of the radicular artery and, under roadmap and magnification, a microcatheter was advanced over the microwire until the fistula was reached. Multiple coils were deployed at the arterial feeder, fistula, and venous pouch. Once arterial flow had significantly decreased the microcatheter was removed. Liquid embolic agent was not used because of the risk of embolization of the artery of Adamkiewicz.

Tips, Tricks & Complication Avoidance • Pediatric spinal arteriovenous fistulas are rare and often associated with hereditary hemorrhagic telangiectasia, as seen in this case. • Current spinal fistula has a high flow component with bilateral radicular arterial feeder, and a large venous aneurysm dilation causing anterior spinal cord compression. Two anterior spinal arteries arise proximal to the radicular arterial feeders. For this reason we chose coil embolization. Liquid embolic material could potentially go into one of the anterior spinal arteries and cause a devastating spinal cord stroke.

• As seen in this case, coil embolization was sufficient to slowly occlude the fistula. Mid-term follow up demonstrated complete fistula obliteration with significant improvement of mass effect and spinal cord edema. Long-term is mandatory as recurrent is not uncommon in pediatric patients. Due to anterior location of this vascular lesion, anterior spinal cord surgical approach in a neonate carries significant morbidity.

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35  Carotid-Cavernous Fistula Embolization Stephan A. Munich, Giuseppe Lanzino, and Leonardo Rangel-Castilla

General Description Carotid cavernous fistulas (CCFs) are characterized by an abnormal connection between the internal carotid artery (ICA) or external carotid artery (ECA) and the cavernous sinus. Most broadly, they can be divided into direct or indirect types. Direct CCFs are formed when a hole in the cavernous segment of the ICA results in a direct connection with the cavernous sinus (Barrow type A classification of CCFs), as is seen when a cavernous ICA aneurysm ruptures. Indirect CCFs are characterized by abnormal shunting to the cavernous sinus from a dural or meningeal branch of the ICA (Barrow type B), a dural or meningeal branch of the ECA (Barrow type C), or dural or meningeal branches from both the ICA and ECA (Barrow type D).

Evidence Spontaneous occlusion of indirect CCFs may occur in 20%–60% of patients. Manual compression of the ipsilateral carotid artery results in similar rates of occlusion for indirect CCFs but results in occlusion of only 17% of direct CCFs. Since detachable balloons were removed from the market, endovascular treatment of CCFs has consisted of coiling or liquid embolic occlusion. In most series, the success of these techniques is > 85% with < 10% morbidity. However, it is not uncommon for patients to experience an immediate post-procedure worsening of symptoms, followed by long-term resolution.

Indications Indirect fistulas are low flow and may thrombose spontaneously or with carotid compression. However, most physicians recommend treatment of these lesions to avoid potential visual symptoms. Direct CCFs require intervention because they are high-flow lesions and will not thrombose spontaneously. Urgent intervention for any CCF is necessary under the following circumstances: • Elevated intraocular pressure (> 25 cm H2O). • Impaired visual acuity. • Elevated intracranial pressure with cortical venous hypertension. Although indirect CCFs may thrombose without treatment, spontaneous resolution of visual symptoms or increased intraocular pressure warrants investigation with angiography. Either of these findings may represent thrombosis of the superior ophthalmic vein (SOV) and development of retrograde cortical venous drainage, which increases risk of hemorrhage.

Neuroendovascular Anatomy As previously mentioned, the Barrow classification of CCFs is based on their arterial anatomy (see General Description). The clinical presentation is much more affected by the venous anatomy. Drainage of the fistula through the SOV results in venous hypertension within the orbit, leading to the typical visual complaints experienced by these patients. However, when the SOV is thrombosed or severely engorged, venous drainage may occur retrogradely through cortical veins, increasing intracranial pressure and putting patients at risk for hemorrhage. The venous anatomy associated with the cavernous sinus also has relevance for treatment strategies. Transvenous embolization is

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the method of choice for indirect fistulas (Fig. 35.1, Video 35.1). The preferred transvenous route of access to the cavernous sinus is the inferior petrosal sinus (IPS) (Fig. 35.2, Video 35.2). Alternative venous conduits to the cavernous sinus include the contralateral IPS, facial vein, superior petrosal sinus, and SOV.

Periprocedure Medications We routinely administer systemic heparin to an activated coagulation time of 250–300 s. If transarterial treatment is pursued with a stent (e.g., flow-diverting stent), dual antiplatelet therapy is administered. For elective cases, aspirin (325 mg) and clopidogrel (75 mg) are administered daily for 5–7 days before the procedure. For emergent cases, loading doses are administered before the procedure (aspirin 650 mg and clopidogrel 600 mg). Post-procedure cranial nerve palsies may occur following embolization or packing of the cavernous sinus. Ophthalmoplegia has been reported in the literature to occur in 2%–5% of patients. In cases in which this occurs, we typically administer a short course of dexamethasone.

Specific Technique and Key Steps Transarterial Route 1. Identification of the direct fistula. Transarterial embolization carries significant risk in Barrow types B–D CCFs because of the risk of embolic reflux into the ICA (Fig. 35.1, Video 35.1). 2. Placement of guide catheter in the distal cervical ICA. The inner diameter of the guide catheter should be large enough to accommodate two microcatheter systems. 3. Identification of the fistulous point. The inflation of a balloon within the ICA and a microinjection may help to identify the exact location of the fistulous point. 4. Microcatheterization through the fistulous point into the cavernous sinus (Fig. 35.1, 35.2, Video 35.1, 35.2). 5. Injection of liquid embolic or deployment of coils into the cavernous sinus. This should begin as deep into the cavernous sinus (as far away from the fistulous point) as possible. 6. During injection of liquid embolic or deployment of coils, a balloon can be inflated within the ICA to protect it (Fig. 35.2, Video 35.2).

Transvenous Route 1. Transfemoral venous and arterial access. Arterial access is needed to help identify the site of the fistula and to confirm obliteration following embolization. 2. Navigation through the heart and into the internal jugular vein with a guide catheter. 3. Microcatheterization of the IPS. The IPS can often be catheterized even when it does not opacify with contrast injections. 4. Injection of liquid embolic or deployment of coils into the cavernous sinus (Fig. 35.2, Video 35.2).

Device Selection The following devices are used in our practice for treatment of CCFs: • 6 or 8 French (F) sheath. • 6F guide catheter (Envoy XB, Codman Neuro; Benchmark, Penumbra; or 8F guide catheter, Neuron MAX, Penumbra).

35  Carotid-Cavernous Fistula Embolization • Microcatheter—SL-10 (Stryker Neurovascular), (MicroVention), Marathon (Medtronic). • Microwire—Synchro 2 (Stryker Neurovascular). • Coils and/or Onyx-34 (Medtronic).

Headway

DUO

Pearls • Proper identification of the type of CCF present is critical. Transarterial endovascular treatment is typically reserved for direct CCFs because of the risk of reflux of embolic material into the ICA.

• Not visualizing the IPS should not deter catheterization attempts. The IPS often can be accessed based on its anatomic location even when it is not visualized with contrast injection. • Injection of embolic material or deployment of coils should occur as deep as possible into the cavernous sinus. Doing this too proximally can obstruct access to the rest of the fistula. • When transarterial and traditional transvenous attempts at treatment fail, alternative methods are direct access (by way of the orbit) of the SOV or direct puncture into the cavernous sinus.

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VI  Brain Arteriovenous Malformations and Fistulas

Case Overview

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CASE 35.1 Indirect Carotid Cavernous Fistula: Transfacial Vein Embolization

• A 56-year-old female developed sudden headache behind her left eye. Mild periorbital edema, double vision, and proptosis appeared several days after. The patient had a significant past medical history of facial trauma 7 years prior to her current symptoms. After evaluation by the ophthalmologist, she was referred to neurosurgery for possible carotid cavernous (CC) fistula.

• Computed tomography (CT) and CT angiography demonstrated multiple enlarged draining veins from the cavernous sinus including the ophthalmic vein sphenoparietal sinus. There were subtle arterial feeders arising from the internal carotid artery (ICA).

Fig 35.1a  CT angiography showing indirect CC fistula. Subtle arterial connection (red arrow) and enlarged draining vein (white arrow).

Fig 35.1b  Artist’s illustration of endovascular embolization of indirect CC fistula.

Fig 35.1c  Indirect CC fistula.

Fig 35.1d  Superior ophthalmic vein.

35  Carotid-Cavernous Fistula Embolization

Fig 35.1e  Inferior petrosal sinus occluded. No access into the fistula.

Fig 35.1f  Facial vein.

Fig 35.1g  Microcatheter in the superior ophthalmic artery.

Fig 35.1h  Coils.

Fig 35.1i  CC fistula obliterated.

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VI  Brain Arteriovenous Malformations and Fistulas Video 35.1  Facial vein embolization of indirect cavernous carotid fistula

Procedure • The patient underwent cerebral angiography/venogram and endovascular embolization of indirect CC arteriovenous fistula. The procedure was performed under general anesthesia and through a right femoral artery and femoral vein approaches. 5,000 units of heparin were administered to achieve an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery and vein access. – Micropuncture kit (2). – 6F sheath (2). • 0.038-inch Glidewire. • 6F Asahi Fubuki guide catheter (Asahi Intecc). • Angle glide catheter (Cook). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple coils. • 6F AngioSeal percutaneous closure device.

An angle diagnostic catheter was introduced in the left and right internal and external carotid arteries and complete cerebral angiograms were obtained. A 6F guide catheter was positioned at the left jugular bulb and access into the inferior petrosal sinus (IPS) was attempted but failed to do so as the IPS was occluded. The guide catheter was pulled back and the external jugular vein was accessed using an angle catheter. Under roadmap and magnification, a microcatheter was advanced into the facial vein all the way to the superior ophthalmic vein and into the fistula draining vein. Multiple coils were deployed and detached until the fistula was obliterated. Postembolization arterial angiography demonstrated complete fistula obliteration.

Tips, Tricks & Complication Avoidance • The majority of the CC fistulas we encounter in clinical practice are symptomatic and deserve management. Treatment is almost exclusively endovascular embolization. We prefer a transvenous approach through the inferior petrosal sinus, contralateral cavernous sinus, or in rare occasions through the superior ophthalmic vein. A combination of coils and liquid embolic agents is typically used. We

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recommend the use of an intra-arterial balloon in the cavernous ICA for protection against liquid embolization into the ICA and intracranial arteries. Sometimes, the angioarchitecture of the fistula is not well understood until the fistula has been partially embolized; therefore, we need to be extremely careful and aware of potential arterial embolization during early stages of the procedure.

35  Carotid-Cavernous Fistula Embolization

Case Overview

CASE 35.2 Direct Carotid Cavernous Fistula: Transvenous and Transarterial Embolization

• A 65-year-old female developed acute bilateral periorbital edema, double vision, and proptosis. Symptoms developed quickly over a period of 5–6 days. The patient did not have any past medical history of significance.

• Computed tomography (CT) and magnetic resonance (MR) angiography demonstrated multiple enlarged draining veins from both cavernous sinus including the ophthalmic vein and sphenoparietal sinuses.

Fig 35.2a  MR angiography showing arterialization of the cavernous sinus and an enlarged superior ophthalmic vein.

Fig 35.2b  Artist’s illustration of endovascular embolization of direct CC fistula.

Fig 35.2c  Direct CC fistula.

Fig 35.2d  Contralateral cavernous sinus coiling.

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Fig 35.2e  Contralateral and ipsilateral cavernous sinus coiling.

Fig 35.2f  Onyx.

Fig 35.2g  ICA occlusion with coils after passing balloon test occlusion.

Fig 35.2h  Right ICA angiography demonstrated obliteration of the fistula with adequate blood flow to the hemispheres.

Video 35.2  Embolization of bilateral direct high-flow CC fistula

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35  Carotid-Cavernous Fistula Embolization

Procedure • The patient underwent cerebral angiography/venogram and endovascular embolization of direct carotid cavernous (CC) arteriovenous fistula. The procedure was performed under conscious sedation and through a right femoral artery and left femoral vein approaches. 5,000 units of heparin were administered to achieve an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery and vein access. – Micropuncture kit (2). – 6F sheath (2). • 0.038-inch Glidewire. • 6F Envoy 6F guide catheter (Cook) (2). • 3 x 7 mm Hyperform Occlusion balloon (Medtronic). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple coils. • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 34 (Medtronic). • 6F AngioSeal percutaneous closure device.

Two 6F guide catheters were advanced and positioned, one at the left internal carotid artery (ICA) and one at the left internal jugular vein. Under road map and magnification, a microcatheter was advanced through the inferior petrosal sinus, and into the contralateral cavernous sinus. Multiple coils were deployed and detached until the right and left cavernous sinus were fully packed with coils. Through the same microcatheter and maintaining the same position, Onyx was injected to fill up the gaps between coils and obliterate the fistula completely. Arterial angiography demonstrates still patency of the fistula. There was no more venous access into the fistula. We performed a balloon test occlusion of the left ICA and the patient passed the test. We proceeded with occlusion of the carotid artery with coils and Onyx. Postembolization right ICA angiography demonstrated complete fistula obliteration and adequate ipsilateral and contralateral blood flow. The patient remained neurologically intact during and after the procedure.

Tips, Tricks & Complication Avoidance • Treatment of CC fistula requires knowledge and understanding of the arterial and venous anatomy. Embolization requires large amounts of time, coils, and liquid embolic agents to achieve a good result. • The first attempt at treatment is the best chance at success. Once access is obtained, the surgeon must embolize until the fistula no

longer fills. Failure of fistula embolization with loss of access is the most worrisome complication, with possible conversion into cortical venous drainage. • Direct CC fistulas can be treated with ICA sacrifice in cases where transvenous embolization is not possible or sufficient.

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Part VII Head and Neck Embolization

VII

36 Endovascular Treatment of Epistaxis

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37 Central Nervous System Tumors

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38 Embolization of Carotid Body Tumors

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39 Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction

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36  Endovascular Treatment of Epistaxis Gary B. Rajah and Leonardo Rangel-Castilla

General Description Epistaxis is a common condition, with more than half of adults experiencing nasal bleeding at some point. Few cases will require endovascular intervention because most can be treated with pressure, nasal packing, or cauterization. Typically, conservative management will suffice for anterior nosebleeds, which are supplied by the Keisselbach triangle. More commonly, posterior nasal bleeds may require nasal packing and/or intervention. There are many causes of uncontrollable epistaxis including idiopathic, traumatic (most commonly an external carotid artery [ECA] branch or a pseudoaneurysm), postsurgical (e.g., after nose and throat procedures, transsphenoidal surgery), neoplasm-related, or associated with ruptured internal carotid artery (ICA) cavernous aneurysms, arteriovenous malformations or fistulas, and congenital syndromes such as Osler-Weber-Rendu syndrome.

Indications Endovascular embolization is indicated for any case of epistaxis that cannot be controlled by conservative measures.

Neuroendovascular Anatomy Most endovascular treatments commence with diagnostic cerebral angiography of the ICA and ECA vessels. The images are carefully analyzed to determine whether an extracranial–intracranial (EC–IC) anastomosis is present. The important anatomical entity when embolizing nasal bleeding is collateral blood supply. Unidentified EC–IC collaterals can be a source of morbidity, including cranial nerve deficits and blindness. Anterior nasal hemorrhages are supplied by the Keisselbach plexus, which is formed by the following ECA branches: sphenopalatine, superior labial, angular, ascending palatine, and anterior ethmoidal arteries. Posterior nasal hemorrhages are supplied by posterior ethmoidal arteries that arise from the ophthalmic artery (a direct branch of the ICA) as well as sphenopalatine (a direct branch from the internal maxillary [IMAX] artery and ECA), ascending pharyngeal (branch of the ECA), and ascending palatine vessels (branch of the facial artery). Posterior pharyngeal hemorrhages can originate from the facial artery and any embolization procedure should be performed beyond the submandibular gland branch. Embolization of posterior nasal hemorrhages involves unilateral distal IMAX embolization. If the hemorrhage persists, contralateral IMAX embolization is performed. If the hemorrhage is severe, the facial artery distal to the submandibular gland branch can be also embolized. We avoid bilateral facial artery embolization because patients could experience facial skin sloughing or tingling.

Important Anastomoses • Meningohypophyseal trunk and/or inferolateral trunk (branch of the ICA) and the artery of foramen rotundum and/or ovale, or accessory meningeal artery (branch of the IMAX). • Recurrent ophthalmic (branch of the ophthalmic artery) and infraorbital artery (branch of the IMAX). • Meningo-ophthalmic artery (branch of the middle meningeal artery) and ophthalmic artery (branch of the ICA).

• Ethmoid vessels from ophthalmic and middle meningeal or IMAX supply can also contribute to EC–IC connections. • The ophthalmic artery can be supplied solely by the middle meningeal vessel in a small percentage of people. • Remember that as embolization proceeds, increased pressure can open a previously unseen anastomosis, so one must always be vigilant.

Perioperative Anesthesia and Medications General anesthesia can be utilized for intubated patients, especially for patients who are hemodynamically unstable or have a compromised airway; otherwise, procedures are performed in awake patients (conscious sedation). We routinely administer systemic heparin to an activated coagulation time above 250 s, unless the hemorrhage is still active.

Specific Technique and Key Steps 1. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, the diagnostic catheter is placed over a curved wire (0.035-inch angled Glidewire, Terumo) and advanced into the aorta under fluoroscopic guidance. 2. A diagnostic study of the ECAs and ICAs is performed (see diagnostic Chapter 6). 3. If the hemorrhage is related to a cavernous ICA aneurysm, see Chapters 23–26. If the hemorrhage is related to a primary or metastatic tumor, see Chapters 37–39. 4. A diagnostic catheter is navigated over a wire, and the IMAX arteries and the facial artery are selected. Angiograms in anteroposterior (AP) and lateral views are obtained of each vessel (Fig. 36.1, 36.2, Video 36.1, 36.2). 5. The more symptomatic side is selected first for distal IMAX artery embolization. 6. A microcatheter can be placed through the diagnostic catheter or a guide catheter can be placed in the ECA under roadmap fluoroscopy (Video 36.1, 36.2). 7. The microcatheter is navigated over the microwire past the temporal branches of the IMAX artery, and a superselective angiogram is obtained. This allows identification of any EC–IC anastomosis (Video 36.1, 36.2). 8. Embolization is then performed with polyvinyl alcohol (PVA) articles or a liquid embolic agent. 9. The PVA particles (with contrast material) can then be injected until stasis of the distal vessel is present. 10. Liquid embolic agents, such as Onyx 18 or 34 (Medtronic), can be administered under subtracted fluoroscopy after filling the microcatheter dead space (usually 0.3 mL) with dimethyl sulfoxide (DMSO) and injecting at 0.1 mL/min DMSO and the initial Onyx (clearing the catheter dead space of DMSO) (Video 36.1, 36.2). 11. The other IMAX artery can be embolized in a similar fashion, and the facial artery on one side can be embolized if the epistaxis did not subside. 12. The catheters are then removed. The nasal packing should be in place for at least 24 h and the patient monitored in the intensive care unit.

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Device Selection The following are common set-ups and devices used for endovascular treatment of epistaxis: • 6 French (F) sheath. • 0.035-inch angled Glidewire (Terumo). • 5F diagnostic catheter. • For Onyx: 0.016-inch DMSO-compatible microcatheter, Headway DUO (MicroVention) catheter, or Apollo detachable-tip catheter (Medtronic). • For PVA: Nautica microcatheter (Medtronic). • Synchro 2 standard wire (0.014-inch wire) (Stryker). • Onyx 18 or 34 (Medtronic) and DMSO, PVA particles (250 micron. • Continuous heparinized flush.

Pearls • When embolizing certain areas, such as lesions supplied by the ascending pharyngeal artery (which also has a cranial nerve supply by way of the neuromeningeal trunk), liquid embolic injection should be done distally to avoid cranial nerve supply. Amytal (amobarbital) and lidocaine should be used on awake patients for Wada testing.

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• Complications can include transient headaches, pain, trismus, facial numbness, paresthesias, permanent ischemic sialadenitis, paresis, cranial nerve palsy, monocular blindness, and skin sloughing. The rate of major complications is generally < 2%. • Patients with Osler-Weber-Rendu syndrome and facial arteriovenous angiomas or malformations may require repeat interventions. Do not use coils or embolize large arteries in these cases, because this can prevent further access in future procedures. • Pseudoaneurysms of the ECA or ECA branches can form years after facial trauma or facial surgery and result in a delayed hemorrhage that may appear idiopathic. • Epistaxis from iatrogenic ICA injury during transsphenoidal surgery is a surgical emergency. Rapid nose packing is performed, and the patient is taken to the angiography suite for endovascular embolization. • Facial arteriovenous malformations or fistulas should be treated with liquid embolic agents (see Chapters 31–33). • Carotid cavernous fistula can also be a source of epistaxis and should be managed appropriately with embolization via transarterial or venous access. • IMAX artery embolization should be distal to the temporalis branches to prevent complications such as jaw claudication, trismus, and pain.

36  Endovascular Treatment of Epistaxis

Case Overview

CASE 36.1 Severe Epistaxis

• A 69-year-old gentleman with a history of myelodysplastic disorder presented to the emergency department with nausea/vomiting, and abdominal pain. He was found to have blood in his stomach. Laboratory results showed severe thrombocytopenia, leukopenia, and anemia (required transfusion). During hospitalization, he required a nasogastric tube. Several days after, he developed severe uncontrol-

lable epistaxis from the right nostril; packing was not sufficient to control the hemorrhage and it was unable to be cauterized by ear, nose, and throat surgery. • Patient taken urgently for embolization of the right sphenopalatine artery (SA). • No head or neck images were obtained.

Fig 36.1a  Artist’s illustration of endovascular embolization of SA for epistaxis.

Fig 36.1b  External carotid artery angiography.

Fig 36.1c  Microcatheter in the maxillary artery.

Fig 36.1d  Microcatheter in the SA.

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Fig 36.1e  SA angiography.

Fig 36.1f  Small 2 x 2 coil deployed at the SA.

Fig 36.1g  Onyx injection.

Video 36.1  Sphenopalatine artery embolization for severe epistaxis

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36  Endovascular Treatment of Epistaxis

Procedure • The patient underwent cerebral angiography and endovascular embolization of right SA. The procedure was performed under conscious sedation and through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Envoy XB DA guide catheter (Cook Medical). • 5F Sofia reperfusion catheter (Microvention). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 0.014-inch Synchro 2 microguidewire (Stryker). • Multiple coils. • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

A 6F guide catheter was positioned at the right common carotid artery. Under road map, an intermediate catheter and a DMSO-compatible microcatheter were advanced distally into the external carotid artery and internal maxillary artery. The intermediate catheter was used to facilitate access into the SA with the microcatheter. An angiogram run was obtained from the microcatheter as baseline and to rule out dangerous anastomosis with the intracranial circulation. Two small coils (2 x 2) were inserted in the artery follow by DMSO and Onyx. Obliteration of the distal segment of the SA was obtained. The majority of the patients with severe epistaxis respond to ipsilateral SA embolization. Bilateral SA embolization is reserved for cases of epistaxis recurrence after an initial embolization. We recommend the use of liquid embolic agents (Onyx) over particles, as these could get reabsorbed over time and the hemorrhage recur.

Tips, Tricks & Complication Avoidance • Particles are the most common embolizing agent used for epistaxis. The disadvantages of particles include the inability to control their distal spread, lack of visualization of their dispersal, and ability to be resorbed by the body over time, even potentially resulting in delayed vessel recanalization. • The successful rate of unilateral SA embolization for the treatment of severe posterior epistaxis with liquid embolic agents is 80%–90%. Less than 10% require a second embolization.

• In the absence of a specific causative target lesion, three-vessel embolization is often recommended. The distal internal maxillary artery at the level of the sphenopalatine vessels bilaterally and the facial artery at or above the level of the superior labial branch on the clinical side of the most hemorrhage, or the largest facial artery.

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Case Overview

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CASE 36.2 Severe Recurrent Epistaxis

• 68-year-old gentleman with severe recurrent uncontrollable epistaxis presented to the emergency department. He had similar episodes 4 days ago, and the hemorrhage was controlled with nasal packing and electrocauterization of the sphenopalatine artery. • He had undergone nasal septoplasty, left turbinectomy, and endoscopic ethmoidectomy for deviated septum and chronic sinusitis 1 month ago.

• He did not have any significant past medical history and no head or neck images were obtained. • Patient taken urgently for embolization of the left sphenopalatine and maxillary arteries.

Fig 36.2a  Artist’s illustration of endovascular embolization of sphenopalatine and internal maxillary artery.

Fig 36.2b  Grade V arteriovenous malformation.

Fig 36.2c  Microcatheter in the internal maxillary artery.

Fig 36.2d  Microcatheter advanced into the sphenopalatine artery.

36  Endovascular Treatment of Epistaxis

Fig 36.2e  Angiography run from the sphenopalatine artery prior to embolization.

Fig 36.2f  Onyx embolization of the sphenopalatine artery and internal maxillary artery.

Video 36.2  Sphenopalatine artery and maxillary artery embolization for recurrent severe epistaxis

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Procedure • The patient underwent cerebral angiography and endovascular embolization of left sphenopalatine and internal maxillary arteries. The procedure was performed under conscious sedation and through a right femoral artery approach. No heparin was administered.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Envoy XB DA guide catheter (Cook Medical). • 5F Sofia reperfusion catheter (Microvention). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

A 6F guide catheter was positioned at the common carotid artery. A road map was obtained and, under magnification, a microcatheter and intermediate catheter were advanced into the external carotid (ECA) and internal maxillary arteries (IMAX). The intermediate catheter was positioned at the ECA and the microcatheter was advanced further into the sphenopalatine artery. An angiography run was obtained to confirm position and rule out any dangerous anastomosis with the intracranial circulation. The microcatheter was primed with DMSO and Onyx 18 was injected slowly and in a pulsatile fashion to facilitate distal embolization. While maintaining active Onyx injection, the microcatheter was slowly pulled back into the IMAX. Postembolization angiography run demonstrated complete obliteration of the sphenopalatine and IMAX arteries.

Tips, Tricks & Complication Avoidance • The most common complications of endovascular procedures for severe epistaxis include transient ischemic attack, stroke, or blindness in 2%. Other less-frequent complications include tissue necrosis and ulceration of the nose, lip, and chin.

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37  Central Nervous System Tumors Kunal Vakharia, Muhammad Waqas, Elad I. Levy, and Adnan H. Siddiqui

General Description

Neuroendovascular Anatomy

Central nervous system (CNS) tumors that tend to be highly vascular can be effectively embolized and treated endovascularly prior to surgical intervention. Tumors most suited to such intervention include meningiomas, hemangioblastomas, paragangliomas, and juvenile angiofibromas. These tumors tend to have distinct locations and arterial feeders that are frequently hypertrophied on angiography. Understanding anatomical location and external carotid artery (ECA) anatomy becomes crucial in surgical planning and preoperative embolization. In addition, surgical planning with respect to timing after embolization becomes increasingly important because tumors that have recently undergone embolization tend to swell and generate perilesional edema. In addition, there is a growing body of literature on endovascular therapy for retinoblastoma as well as possible endovascular intervention for glioblastomas and other tumors of CNS origin.

External Carotid Artery Anatomy

Evidence for Tumor Embolization • Teasdale et al in 19841 and Wakhloo et al in 19932 demonstrated that embolization of meningiomas can reduce the need for blood transfusions intraoperatively as well as decrease the length of the surgical procedure. • Data suggest a 1.6%–9% reported incidence of cranial nerve palsy after small-particle embolization of feeding vessels primarily in meningiomas and paragangliomas. • It has been suggested that waiting 7–10 days postembolization may allow for collateral vessels to supply the tumor with blood, warranting early surgical resection after embolization. • Roberson et al. in 19793 first described embolization of vascular pedicles for juvenile angiofibromas. Since then, embolization of ECA feeders to such tumors has shown a reduction in intraoperative blood loss. • Embolization of hemangioblastomas and hemangiopericytomas has shown some effectiveness in reducing intraoperative blood loss. • White et al. in 20084 demonstrated that risk for preoperative embolization for cervical paragangliomas was low and the procedure offered significant hemostasis intraoperatively. • Most studies on embolization for spinal tumors lack a control arm; yet preoperative embolization is widely accepted to reduce the intraoperative blood loss in these cases.

Indications Highly vascular tumors may potentially warrant embolization for selective delivery of chemotherapeutic medications or embolizates. Embolization is considered in this chapter, although the principles of chemotherapeutic delivery are similar. Embolization is performed for highly vascular skullbase lesions. Preoperatively, the goals of treatment should be discussed with patients and specifically identified. Typical indications include devascularizing tumor beds, embolizing deep or difficult to find arterial pedicles, or palliative management in select cases. Operations for vascular spinal tumors like hemangioblastoma, hemangioma, aneurysmal bone cyst, giant cell tumor, osteoblastoma, and metastatic deposits from renal cell carcinoma or the thyroid gland are considered technically difficult cases. Patients can have massive blood loss during the surgical resection of these tumors. In addition to vascularity, extent of disease, number of vertebral levels involved and bleeding during approach to the tumor can still cause significant blood loss.

The ECA primarily supplies tissues of the face, neck, and scalp. There are many extracranial-to-intracranial anastomoses that are crucial to understanding therapeutic embolization in this vasculature. Understanding the unique anatomy for each tumor is important, although they may have the same blood supply pattern because of a similar location (i.e., typical locations tend to be fed by typical arterial branches). Meningiomas and other dural-based lesions tend to arise in certain locations. Parasagittal meningiomas are often fed by ethmoidal arteries and the falcine artery; parasellar meningiomas are often fed by accessory and recurrent meningeal arteries from the internal maxillary artery; frontobasal meningiomas, including planum sphenoidale and sphenoid wing meningiomas, are often supplied by the inferolateral trunk from the internal carotid artery (ICA) as well as anterior and posterior ethmoidal vessels from the internal maxillary artery and the artery of the foramen rotundum. Tentorial meningiomas have been shown to have a robust supply from the tentorial artery off the ICA, petrosquamosal branch of the middle meningeal artery, and transmastoid branch off the occipital artery. Similarly, understanding the complex anatomy of the ascending pharyngeal artery is important when planning for embolization of paragangliomas in both the jugular foramen and cervical region. The intricate nature of the anterior ascending pharyngeal branches tends not to contribute to the vascular supply for paragangliomas. The posterior neuromeningeal and jugal branches are the most common sources of blood supply for these tumors. Planning for access as distally as possible while understanding the relation of the vessel to the skull base can help avoid cranial nerve palsies.

Spinal Cord Anatomy The spinal cord is supplied by three longitudinal arteries (one anterior spinal artery and two posterior spinal arteries) that receive contributions from the spinal branches of the segmental arteries, also called radiculomedullary arteries. The radiculomedullary arteries also supply the spinal roots, dura, and bony wall of the spinal canal. Each radiculomedullary divides into an anterior and a posterior branch. The anterior radiculomedullary arteries divide into ascending and descending branches that anastomose to form the anterior spinal artery in the midline. The descending branch of the anterior radiculomedullary artery joins the midline anterior spinal artery in a characteristic “hairpin” configuration that can be identified on spinal angiography. The junctions between the posterior radiculomedullary arteries and the posterior spinal arteries also exhibit a characteristic hairpin configuration but are located off the midline. The great anterior radiculomedullary artery, commonly known as the artery of Adamkiewicz, arises at the T9 to T12 vertebral level in 75% of individuals, most often on the left side. When it arises above the T8 vertebral level or below the L2 level, there is usually a second major radiculomedullary arterial supply to the anterior spinal artery. At the cervical level, the radiculomedullary arteries arise from the vertebral artery and the ascending and deep cervical arteries. Additional contributions may be present from anastomoses with the ECA via the occipital and ascending pharyngeal arteries. At the thoracolumbar level, the radiculomedullary arteries arise from the supreme intercostal, posterior intercostal, and lumbar arteries. The blood supply to the sacrum and the cauda equina are via the lateral sacral and the iliolumbar arteries from the internal iliac artery. There is also a small contribution from the median sacral artery.

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Periprocedural Medications Preprocedurally, patients should be started on corticosteroids for large tumors and those causing neural compression. In addition, premedication before surgery or endovascular therapy may be necessary for patients taking medications specific to the pathology of their tumor; for example, β-blockers may need to be administered preoperatively to patients with paragangliomas. Lidocaine can be administered at the site of the skin puncture prior to embolization to help prevent local edema and pain. Injections of dimethylsulfoxide into the tumor before embolization can potentially be helpful in liquefying the tumor during procedural resection, although reports of this therapy are anecdotal. Systemic heparinization is administered during the procedure because of the risk of intraprocedural thrombus formation. A weightbased intravenous bolus of heparin aimed at an activated coagulation time of 250–300 s may limit thromboembolic complications. Heparin is administered before selective angiography of the feeding vessels. For acute thrombus formation during the procedure, a glycoprotein IIb/IIIa inhibitor (e.g., eptifibatide) is injected intra-arterially.

Specific Technique and Key Steps The key steps for embolization of arterial pedicles to CNS tumors are described here (Fig. 37.1-37.3, Video 37.1-37.3). The principles also apply to the delivery of chemotherapeutic agents. 1. A 6 or 8 French (F) sheath is inserted in the femoral artery. 2. After the femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a curved wire (0.035-inch angled Glidewire, Terumo) into the aorta. This maneuver is completed under fluoroscopic guidance. 3. Depending on the arch anatomy, the guide catheter can be brought up directly over the 0.035-inch angled Glidewire or advanced over a 4–5F intermediate diagnostic catheter, such as a Vitek (Cook Medical) or Berenstein catheter (Cook Medical). 4. Cerebral angiography is performed to obtain a baseline set of images of the intracranial vasculature and extracranial vasculature to identify arterial pedicles (Video 37.1-37.3). 5. Bilateral ECA injections are important to obtain an understanding of the vascular supply to these tumors. 6. When the tumor is supplied by meningeal vessels, superselective catheterization of target meningeal vessels is important to understanding the anastomoses as well. 7. Microcatheter navigation is performed distally into the target vessel. Selective microcatheter injections are performed to demonstrate tumor vascularity and to confirm that the catheter is as distal in the vessel as possible to prevent cranial nerve injury (Fig. 37.1-37.3, Video 37.1-37.3). 8. Choice of embolic agents including Onyx (Medtronic), N-butyl-2cyanoacrylate polyvinyl alcohol and acrylic particles are important. Smaller particles tend to penetrate the tumor vasculature although the risk of neurological complication is higher. Typically, particles > 150 μm are suggested. 9. Wada testing can be performed if there is concern for anastomoses to the ophthalmic artery or other intracranial vessels. 10. Embolic agents are injected in a free-flow manner under negative roadmap imaging to clearly visualize how much tumor penetration has been achieved. 11. The embolic agent plug is broken, and the microcatheter is removed from the guide catheter. 12. A final (i.e., control) cerebral angiogram is recommended to assess for smooth synchronized perfusion, looking specifically for delayed capillary filling or other larger occlusion (i.e., vessel dropout).

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Special Considerations for Spinal Vascular Tumors • A detailed digital subtraction spinal angiogram should be performed in all suspected cases of vascular spinal tumors to visualize the vascular supply of the tumor and normal spinal cord. • It is often necessary to catheterize arteries at least two levels above and below the level of pathology. • For cervical tumors, the vertebral arteries, ECAs, thyrocervical trunk, costocervical trunk, and extreme intercostal arteries must be injected during angiography. • For lumbosacral tumors, in addition to assessing segmental vessels both internal iliac arteries and median sacral artery must be injected. The artery of Adamkiewicz and feeding arteries with concomitant medullary supply or en passage vessels must also be recognized before embolization. These considerations are important to avoid serious complications like spinal cord ischemia and infarction.

Device Selection In the authors’ and editors’ practice, the following are common set-ups and devices used for aneurysmal coil embolization: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy DA XB, DePuy Synthes or Benchmark, Penumbra). • 0.035-inch angled Glidewire. • Intermediate 5F diagnostic catheter (Vitek, Cook). • Microcatheter (Headway DUO, MicroVention; Marathon, Medtronic). • Microwire (Synchro 2, Stryker; Synchro 10, Stryker; 0.014 inch, Asahi Chikai). • A Distal Access Catheter (Stryker) may be warranted if multiple distal vessels need to be selected with proximal tortuosity. For spinal cases, the following devices are preferred: • 6F guide catheter or 5F Multipurpose Access catheter (Cordis) after selection with a Mikaelson (Soft-Vu) or Cobra (Cook Medical) catheter. • 0.035-inch angled Glidewire. • Intermediate catheter in robust segmental arteries (Distal Access Catheter, Stryker). • Synchro 2 or Synchro 10 microwire (Stryker). • Marathon (Medtronic) or Headway DUO microcatheter.

Pearls • Typically, surgery should be performed 2–4 days from embolization to avoid significant swelling and postnecrotic bleeding. Waiting for postembolization swelling to subside can facilitate resection around tumor capsules for certain tumors, such as meningiomas. • Adverse events including injury to cranial nerves VII and XII are important to recognize. Complications typically relate to the size of the embolic particle chosen and location of embolization in the meningohypophyseal trunk, middle meningeal artery, accessory meningeal artery, and ascending pharyngeal artery (Video 37.3). • Selective injections in both ECAs are important to understand the angioarchitecture of skull base tumors. Paragangliomas in the jugular foramen may recruit blood supply from both ascending pharyngeal branches (Video 37.3). • Preoperative clinical assessment is crucial to understanding how aggressive to be with embolization as well as potential complications associated with arterial pedicles that supply associated cranial nerves. • Identification of major feeding arteries, especially for meningiomas and paragangliomas, can be seen when pooling of contrast material is seen with early filling of veins, suggesting a shunt. This phenomenon is often seen in more aggressive tumor pathologies.

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References [1] Teasdale E, Patterson J, McLellan D, Macpherson P. Subselective preoperative embolization for meningiomas. A radiological and pathological assessment. J Neurosurg. 1984;60(3):506–511. [2] Wakhloo AK, Juengling FD, Van Velthoven V, et al. Extended preoperative polyvinyl alcohol microembolization of intracranial meningiomas: Assessment of two embolization techniques. AJNR Am J Neuroradiol. 1993;14(3):571–582. [3] Roberson GH, Price AC, Davis JM, Gulati A. Therapeutic embolization of juvenile angiofibroma. AJR Am J Roentgenol. 1979;133(4):657–663. [4] White JB, Link MJ, Cloft HJ. Endovascular embolization of paragangliomas: A safe adjuvant to treatment. J Vasc Interv Neurol. 2008;1(2):37–41.

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Case Overview

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CASE 37.1 Hypervascular Extra-Axial Cerebellar Tumor: Onyx Embolization

• A 46-year-old female with acute and chronic headaches was found to have an intracranial neoplasm. She did not have any past medical history of significance. Her neurological examination was relevant for dysmetria and intentional tremor.

• Computed tomography and magnetic resonance imaging (MRI) demonstrated a large hypervascular posterior fossa tumor causing mass effect and cerebellar edema. The images were consistent with meningioma.

Fig 37.1a  MRI demonstrated the posterior fossa meningioma.

Fig 37.1b  Artist’s illustration of a large posterior fossa meningioma embolization.

Fig 37.1c  Arterial supply directly from VA.

Fig 37.1d  Arterial supply directly from VA.

37  Central Nervous System Tumors

Fig 37.1e  Microcatheter in feeding artery.

Fig 37.1f  Hypervascular tumor blush.

Fig 37.1g  Onyx injection.

Fig 37.1h  Postembolization angiography with no evidence of tumor hypervascularity.

Video 37.1  Intra-axial cerebellar hypervascular tumor embolization

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Procedure • The patient underwent cerebral angiography and endovascular embolization of right posterior fossa meningioma. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin was administered were administered to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

A 071 flexible guide catheter was positioned at the right vertebral artery (VA). Multiple intracranial angiography runs were performed to obtained adequate working views for embolization. The tumor arterial feeders originated from the extracranial V3 segment of the right VA. Under road map and magnification, a DMSO-compatible 0.017inch microcatheter was advanced over a microwire into the larger tumor arterial feeder. An angiography run from the microcatheter was obtained to assess catheter position and tumor vascularity. The microcatheter was purged with DMSO and Onyx was injected slowly and in a pulsatile fashion to penetrate the liquid embolic material within the tumor. Minimal amount of reflux was tolerated to prevent Onyx material into the VA.

Tips, Tricks & Complication Avoidance • Embolization approaches include transarterial, direct puncture, and a combination of these methods. Ideal tumor embolization is achieved with occlusion of the very small vessels within a tumor, while sparing supply to normal adjacent tissue. Liquid and particulate embolic materials are effective in penetrating small vessels, and meticulous use of these materials is essential in preventing unintended occlusions. • Upon contact with the blood, DMSO diffuses out and Onyx. This polymer hardens on the outer surface first, then gradually polymerizing

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toward the core over several minutes. This property allows longer injections of this material. Using this technique, Onyx can be used to embolize the tumor bed. This liquid embolic agent can penetrate the tumor bed and can provide controlled embolization of the tumor vascular bed with good penetration. Percutaneous embolization with Onyx has also been described. • Dangerous anastomoses have to be rule out prior to injections of liquid embolic materials.

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Case Overview

CASE 37.2 Hypervascular Intra-Axial Cerebellar Tumor: Onyx Embolization

• A 54-year-old male presents with subacute onset of gait imbalance, vertigo, and lack of coordination. He did not have any past medical history of significance. His neurological examination was relevant for dysmetria and nystagmus.

• Computed tomography and magnetic resonance imaging (MRI) demonstrated a large cystic tumor at the left cerebellar hemisphere. The tumor had a hypervascular enhancing nodule and a large cyst causing mass effect on cerebellum, brainstem, and fourth ventricle. Images were consistent with a hemangioblastoma.

Fig 37.2a  MRI demonstrated the large cystic cerebellar tumor with the enhancing nodule.

Fig 37.2b  Artist’s illustration of a cerebellar intra-axial tumor embolization.

Fig 37.2c  Hemangioblastoma supplied by the left superior cerebellar artery.

Fig 37.2d  Supraselective angiography of the superior cerebellar artery branch prior to embolization.

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Fig 37.2e  Onyx embolization.

Fig 37.2f  Complete tumor embolization.

Fig 37.2g  Complete tumor resection.

Video 37.2  Extra-axial posterior fossa hypervascular tumor embolization

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37  Central Nervous System Tumors

Procedure • The patient underwent cerebral angiography and endovascular embolization of the hypervascular tumor nodule. The procedure was performed under conscious sedation and through a right femoral artery approach. 4,500 units of heparin was administered to obtain an activating clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.013-inch Apollo microcatheter (Medtronic). • 0.010-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 18 (Medtronic). • 6F AngioSeal percutaneous closure device.

A 6F guide catheter was positioned at the left vertebral artery. Under road map and magnification, a detachable-tip microcatheter was advanced into the basilar artery and left superior cerebellar artery (SCA). A detachable-tip microcatheter was selected because of the small size of the distal SCA branch and the possibility of Onyx reflux. The microcatheter was advanced as proximately as possible to the tumor. A supraselective anigography run was obtained with the mirocatheter to delineate tumor size and distance from the microcatheter tip to the tumor. The microcatheter was purged with DMSO and Onyx 18 was slowly injected until obliteration of the tumor was obtained. Because of the small size of the tumor, it only required 0.5 mL of Onyx. The syringe plunger was pulled back and the microcatheter was removed. The tip did not detach. The patient remained neurologically intact and was taken to surgery for tumor resection.

Tips, Tricks & Complication Avoidance • Intra-axial tumor embolization is not as common as extra-axial tumors (e.g., meningiomas). The majority of intra-axial tumors do not require preoperative embolization; however, certain selected tumors (hemangioblastoma, metastasis) could benefit from embolization prior to surgical resection.

• Techniques and precautions similar to arteriovenous malformation embolization should be followed, including supraselective Wada testing prior to embolization, differentiation of en passage vessels, and minimal tolerance for Onyx reflux.

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Case Overview

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CASE 37.3 Large Hypervascular Skull Base Tumor: PVA Embolization Particles

• An 18-year-old male presented with subacute onset of facial pain, intermittent diplopia, difficulty swallowing, and mandibular joint pain. He did not have any past medical history of significance. His neurological examination was relevant for mild facial palsy.

• Computed tomography and magnetic resonance imaging (MRI) demonstrated a very large enhancing mass at the right maxillary and infraorbital region. The tumor was hypervascular with a necrotic center, causing mass effect on nasal sinuses and orbit.

Fig 37.3a  MRI demonstrated the large hypervascular skull base tumor.

Fig 37.3b  Artist’s illustration of a large skull base tumor embolization.

Fig 37.3c  Anteroposterior (AP) and lateral external carotid angiogram showing the tumor hypervascularity.

Fig 37.3d  External carotid angiography roadmap for particles injection.

37  Central Nervous System Tumors

Fig 37.3e  Supraselective middle meningeal artery angiography roadmap for particles injection.

Fig 37.3f  AP and lateral external carotid angiography demonstrating complete tumor embolization.

Fig 37.3g  3-month follow-up MRI demonstrating gross total tumor resection.

Video 37.3  Skull base hypervascular tumor embolization

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Procedure • The patient underwent cerebral angiography and endovascular embolization of the hypervascular tumor. The procedure was performed under general anesthesia and through a right femoral artery approach. 5,000 units of heparin was administered to obtain an activated clotting time of more than 250.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • Benchmark 071 guide catheter (Penumbra). • 0.027-inch Marksman (Medtronic). • 0.010-inch Synchro 2 microguidewire (Stryker). • Polyvinyl alcohol (PVA) particles (Boston Scientific). • 6F AngioSeal percutaneous closure device.

Six-vessel cerebral angiogram was performed to assess tumor arterial supply and dangerous collaterals into the intracranial circulation. A 6F guide catheter was positioned at the right external carotid artery (ECA). Multiple branches from the ECA give blood supply to the tumor including the middle meningeal artery, internal maxillary artery, and facial artery. Under road map and magnification, a large (0.027-inch) microcatheter was advanced over a microwire into the internal maxillary artery. Large PVA particles were mixed with contrast and injected slowly until no more evidence of hypervascularity. The same step was done in the middle meningeal artery and facial artery. Before each artery embolization, an angiography was obtained to rule out dangerous anastomosis with intracranial circulation prior to particles injection. The patient remained neurologically intact and underwent surgical resection of the tumor the following day.

Tips, Tricks & Complication Avoidance • PVA particles are made from a PVA foam sheet that is vacuum dried and rasped into particles. The particles are filtered with sieves and are available in sizes ranging from 100 μm to 1,100 μm. • Use of PVA particles of 45–150 μm followed by 150–250 μm can be successful in tumor embolization. Smaller particles 45–150 μm penetrate the capillary vascular bed of the tumor and aid in devascularization. These particles often devascularize to the extent that the tumor undergoes necrosis. Larger particles 150–250 μm

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embolize smaller arterioles in the tumor bed. If a dangerous anastomosis is suspected, larger particle sizes can be utilized to prevent accidental embolization of the anastomosing branches. • Dangerous anastomoses include internal maxillary artery with internal carotid artery (via vidian artery) and ophthalmic artery, middle meningeal artery with internal carotid artery, and superficial temporal artery with ophthalmic artery (via supraorbital artery).

38  Embolization of Carotid Body Tumors Kunal Vakharia, Muhammad Waqas, Alexander R. Neary, Adnan H. Siddiqui, and Elad I. Levy

General Description

Neuroendovascular Anatomy

Paragangliomas are rare neuroendocrine tumors derived from extraadrenal paraganglia of the autonomic nervous system. Carotid body tumors are typically situated at the bifurcation of the common carotid artery and located within the adventitia of the common carotid artery. This is the most common neck paraganglioma and is typically supplied by branches off the external carotid artery (ECA), most commonly the ascending pharyngeal artery. Carotid body tumors have been described as slow-growing tumors with a growth rate of < 0.5 cm per year. Observation may be warranted in elderly patients who are otherwise asymptomatic from this lesion. Radiotherapy may be warranted in certain patient populations after considering the potential risks and benefits to the patient. Since the first embolization of a carotid body tumor prior to surgical resection was performed in 1980 by Schick et al1, there has been significant controversy over the potential benefit in this particular situation. It is important to weigh the potential risks associated with endovascular intervention against the potential intraoperative benefits to the patient and surgeon.

The ECA primarily supplies the tissues of the face, neck, and scalp. The ECA has many anastomoses with the internal carotid artery (ICA), which are important to recognize when planning preoperative embolization for carotid body tumors. In addition, recognition of collateral ECAs that supply the tissues around the tumor is critical because collateral branches should be avoided during embolization to allow for the best chance of postoperative wound healing. The ascending pharyngeal artery territory is the key to understanding the blood supply to carotid body tumors as well as the blood supply to the skull base because the artery supplies the intermediate zone bordered anteriorly by the internal maxillary artery territory and posteriorly by the occipital artery territory. Embryologically, the ascending pharyngeal artery originates from the third branchial arch artery and is derived from the ICA. It is important to recognize the importance of the ascending pharyngeal artery in supplying cranial nerves as they exit the skull base. The pharyngeal branches tend to arise from the anterior division of the main artery or pharyngeal trunk. There are many branches that anastomose with the internal maxillary artery territory and have potential collaterals to the inferolateral trunk of the ICA. The neuromeningeal trunk has two principal branches, the hypoglossal artery and the jugular artery. The hypoglossal artery supplies the hypoglossal canal as well as dura of the anterior posterior fossa and foramen magnum region, contributing to the odontoid arcade. The jugular artery tends to travel through the jugular foramen supplying cranial nerves IX, X, and XI and has multiple anastomoses with the posterior circulation.

Evidence Regarding Tumor Embolization • Since the initial report by Shick et al., many authors have reported their experience with preoperative embolization and the associated impact on intraoperative blood loss, cranial nerve injury, need for transfusion, and risk of stroke. A multivariate meta-analysis by AbuGhanem et al2 in 2015 found that there is no statistically significant impact of preoperative embolization for any of the above criteria. • All studies to date provide only retrospective analyses comparing preoperative embolization versus no embolization. • Power et al3 in 2012 reported the single largest retrospective study consisting of 131 patients who underwent resection of carotid body tumors with and without preoperative embolization. They found a statistically significant difference in estimated blood loss during the surgical resection (263 mL in the pre-embolization group vs. 599 mL in the nonembolized group [P = 0.002]). In addition, 21 of 33 (64%) patients who underwent preoperative embolization had a cranial nerve injury compared with 39 of 71 (55%) patients who did not undergo embolization (these differences were not statistically significant). The most common cranial nerve neuropathies involved cranial nerves IX, X, and XII. • Gwon et al4 showed that the Shamblin classification was related to the risk of stroke (P = 0.041) and that tumor size was not.

Indications Highly vascular carotid body tumors may potentially warrant embolization. Although several studies and a meta-analysis have demonstrated that there is no statistically significant difference between outcomes during surgery for carotid body tumors that have undergone preoperative embolization versus those that have not, reducing intraoperative blood loss can be an important adjunct. In addition, no prospective trial has evaluated the potential benefits of Shamblin class II and III lesions or lesions invading the media or intima of the carotid artery, which may warrant preoperative embolization to aid in safer dissection as well as limiting operative time and cranial nerve injury.

Periprocedural Medications Preprocedurally, patients with large tumors and tumors causing neural compression should be placed on corticosteroids. In addition, medications specific to tumor pathology may need to be administered prior to surgery or endovascular therapy, meaning potentially administering β-blockers preoperatively for paragangliomas. Lidocaine can be administered prior to embolization to help prevent local edema and pain. Injections of dimethylsulfoxide into the tumor prior to embolization can potentially be helpful in liquefying the tumor during procedural resection, although the evidence for this is anecdotal. Systemic heparinization is administered during the procedure because of the ever-present risk of intraprocedural thrombus formation. A weight-based intravenous bolus of heparin aimed at an activated coagulation time of 250–300 seconds may limit thromboembolic complications. Administration of the heparin before crossing the stenotic lesion may limit thrombus formation on devices positioned within the ICA. For acute thrombus formation during the procedure, a glycoprotein IIb/IIIa inhibitor (e.g., eptifibatide) is utilized.

Specific Technique and Key Steps Key steps for the embolization of arterial pedicles to carotid body tumors are described here (Fig. 38.1, Video 38.1). 1. A 6 or 8 French (F) sheath is inserted in the femoral artery. 2. After a femoral angiogram has been performed to confirm the absence of any irregularity or dissection, a guide catheter is advanced over a curved wire (0.035-inch angled Glidewire, Terumo) into the aorta. This maneuver is completed under fluoroscopic guidance.

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VII  Head and Neck Embolization 3. Depending on the arch anatomy, the guide catheter can be brought up directly over a 0.035-inch angled Glidewire or advanced over a 4–5F intermediate diagnostic catheter, such as a Vitek (Cook Medical) or Berenstein catheter (Cook Medical). 4. Cerebral angiography is performed to obtain a baseline set of images of the intracranial vasculature and extracranial vasculature to identify arterial pedicles (Video 38.1). 5. Bilateral ECA injections are important to understanding the vascular supply to these tumors (Video 38.1). 6. Superselective catheterization of target extracranial vessels is important to understanding anastomoses. 7. Microcatheter navigation is performed distally into target vessel. Selective microcatheter injections are done to demonstrate tumor vascularity and to confirm that catheter is as distal in the vessel as possible to prevent cranial nerve injury (Fig. 38.1, Video 38.1). 8. The choice of embolic agents, including Onyx (Medtronic), N-butyl2-cyanoacrylate, and polyvinyl alcohol (PVA) and acrylic particles is important. Smaller particles tend to penetrate tumor vasculature, although their use is associated with a higher risk of neurological complications. Typically, particles > 150 μm are suggested. 9. Wada testing can be performed if concern exists for anastomoses to ophthalmic or other intracranial vessels. 10. Embolic agents are injected under negative roadmap guidance to clearly visualize the amount of tumor penetration achieved (Fig. 38.1, Video 38.1). 11. The embolic agent plug is broken, and the microcatheter is removed from the guide catheter. 12. A final (i.e., control) cerebral angiogram is recommended to assess for smooth synchronized perfusion, looking specifically for delayed capillary filling or other larger occlusion (vessel dropout).

Device Selection The following are common set-ups and devices used for carotid body tumor embolization: • 6 or 8F sheath. • 6F guide catheter (i.e., Envoy DA XB, Codman Neuro or Benchmark, Penumbra). • 0.035-inch angled Glidewire. • Intermediate 5F diagnostic catheter (Vitek). • Microcatheter (Headway Duo, MicroVention; Marathon, Medtronic; or balloon, Scepter C, MicroVention). • Microwire (Synchro 2, Stryker; Synchro 10, Stryker; Asahi Chikai 0.014-inch, Asahi Intecc). • A distal access catheter (Stryker) may be warranted for the selection of multiple distal vessels with proximal tortuosity.

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Pearls • Adverse events, including cranial nerve injury to IX, X, and XII, are important to recognize. Complications typically relate to size of embolic particle chosen and location of embolization in the neuromeningeal trunk of the ascending pharyngeal artery, as well as branches of the hypoglossal artery and jugular branches. Understanding the location of the vertebral artery is also important. When embolic agents flow toward the vertebral artery, the injection should be stopped because these collaterals may not be readily visualized during angiography. • Provocative testing, such as superselective injection of amytal (Amobarbital) and lidocaine to identify intracranial anastomoses and blood supply to the cranial nerves, has been used prior to embolization to minimize the risk of cranial nerve palsy. • Patients should be advised about potential pain near the embolization location as well as the potential for skin and mucosal necrosis. This complication is typically a result of cutaneous branches of arteries supplying the tumor that are occluded during embolization and can lead to poor postoperative wound healing. • An intentional delay of 1 to 2 days between embolization and surgery allows time for edema to resolve but not enough time for reconstitution or recruitment of feeding arteries or for the development of inflammation in the waiting period. • Gelfoam injection or PVA can be a useful adjunct, especially in small vessels and very distally, close to the tumor bed. • Embolization is typically considered for large lesions > 3 cm or Shamblin class II or III lesions (Fig. 38.1, Video 38.1).

References [1] Schick PM, Hieshima GB, White RA, Fiaschetti FL, Mehringer CM, Grinell VS, Everhart FR. Arterial catheter embolization followed by surgery for large chemodectoma. Surgery 1980 Apr;87(4):459-64. [2] Abu-Ghanem S, Yehuda M, Carmel NN, Abergel A, Fliss DM. Impact of preoperative embolization on the outcomes of carotid body tumor surgery. A meta-analysis and review of the literature. Head Neck 2016 Apr;38 Suppl 1:E2386-94. [3] Power AH, Bower TC, Kasperbauer J, Link MJ, Oderich G, Cloft H, Young WF Jr, Gloviczki P. Impact of preoperative embolization on outcomes of carotid body tumor resections. J Vasc Surg 2012 Oct;56(4):979-89. [4] Gwon JG, Kwon TW, Kim H, Cho YP. Risk factors for stroke during surgery for carotid body tumors. World J Surg 2011 Sep;35(9):2154-8.

38  Embolization of Carotid Body Tumors

Case Overview

CASE 38.1 Carotid Body Tumor Embolization

• A 26-year-old female presented with bilateral neck masses and right neck pain. She did not have any neurological symptoms. Her past medical history was significant for chronic headaches and hypertension. On examination, she had a large palpable mass at the anterior right neck. Her neurological examination was normal.

• Computed tomography (CT) angiography showed bilateral enhancing masses at the cervical carotid artery bifurcation. The right-side tumor was significantly larger than the left, causing moderate mass effect and tracheal deviation.

Fig 38.1a  CT angiography showing a right carotid artery tumor.

Fig 38.1b  Artist’s illustration of endovascular embolization of carotid body tumor.

Fig 38.1c  Anteroposterior and lateral view of the carotid body tumor.

Fig 38.1d  Microcatheter in arterial branch prior to embolization.

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Fig 38.1e  Onyx embolization.

Fig 38.1f  Significant tumor embolization in preparation for surgery.

Video 38.1  Carotid body tumor embolization

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38  Embolization of Carotid Body Tumors

Procedure • The patient underwent cerebral angiography and endovascular embolization of carotid artery tumor. The procedure was performed under conscious sedation and through a right femoral artery approach. 5,000 units of heparin were administered to achieve an activated clotting time of more than 250.

Device List

Device Explanation

• Standard femoral artery. – Micropuncture kit. – 6F sheath. • 0.038-inch Glidewire. • 6F Envoy 6F guide catheter (Cook). • 0.017-inch Headway DUO microcatheter (Microvention). • 0.014-inch Synchro 2 microguidewire (Stryker). • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 34 (Medtronic). • 6F AngioSeal percutaneous closure device.

A 6F guide catheter was positioned at the right external carotid artery (ECA). Under road map and magnification, a microcatheter was advanced through the distal ECA into the most superior arterial branch feeding the carotid tumor. Microcatheter position was confirmed and a Wada test was done prior to embolization. The microcatheter was purged with DMSO and Onyx 34 was injected slowly into the tumor. Once a significant amount of reflux was observed, the microcatheter was removed. This embolization procedure was repeated with two more tumor arterial feeders. Postembolization right ECA angiography demonstrate significant obliteration of the carotid tumor. The patient remained neurologically intact during and after the procedure, and was taken to surgery the following day.

Tips, Tricks & Complication Avoidance • Preoperative transarterial hyperselective embolization can significantly reduce blood loss and shorten operative time. • Embolization can be done through a transarterial or direct puncture route. The most commonly used material includes Onyx, n-BCA, and PHIL. For an effective embolization, the material should penetrate in the parenchyma of the tumor. For these reasons, coils are not used.

• Complications include thromboembolism and cranial nerve ischemia. The most common nerves affected include facial nerve, glossopharyngeal, and vagus nerves. • Be aware of potential dangerous anastomosis between extracranial and intracranial circulation.

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39  Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction Lorenzo Rinaldo, Giuseppe Lanzino, and Leonardo Rangel-Castilla

General Description Carotid blowout syndrome (CBS) refers to the signs and symptoms associated with the rupture of the extracranial carotid artery or one of its branches. It can be a life-threating complication of head and neck cancer and radiation therapy. CBS typically occurs in cases of head and neck cancers, with an estimated incidence of 4.3% in patients undergoing radical neck dissection. Risk factors for CBS include previous radiotherapy (particularly radiation-induced necrosis), recurrent tumors, and the presence of pharyngocutaneous fistulae. Symptoms of CBS are usually related to oral, nasal, or peritracheal acute bleeding or mass effect from a hematoma on laryngeal structures (e.g., respiratory compromise). Prior to the advent of endovascular technology, treatment of CBS consisted of neck exploration and carotid artery ligation. Surgical exploration in the setting of a previously irradiated field, as is often the case in patients with CBS, is challenging and has been associated with unacceptably high rates of perioperative morbidity and mortality, reaching 40% and 60%, respectively. As such, surgical treatment of CBS has largely been abandoned in favor of endovascular techniques. The most common endovascular treatment strategies include carotid occlusion with coil and/or Onyx (Medtronic) embolization and carotid stent grafting. Technical success rates for both procedures are similar with comparable rates of periprocedural morbidity and mortality. Regardless of technique, the most frequent complication is carotid rebleeding, which occurs in roughly 25% of patients within 1 week of the procedure, although delayed rebleeding is not uncommon. Rebleeding may be more common in patients treated with stenting, whereas coil embolization may be associated with higher rates of postprocedure cerebral infarction, although the latter assertion is controversial. Reflected by an estimated median survival time of 3 months, the overall prognosis after treatment of CBS remains poor.

Indications In general, presentations of CBS have been subdivided into one of three categories: (1) a self-limited, or sentinel, hemorrhage, (2) an exposed carotid artery representing a potential carotid blowout, and (3) uncontrolled hemorrhage resulting in hemorrhagic shock. The former two presentations are high risk for a subsequent life-threatening hemorrhage and warrant urgent endovascular intervention.

Neuroendovascular Anatomy The internal carotid artery (ICA) normally originates from the common carotid artery (CCA) at the C3-4 or C4-5 level of the cervical spine. In general, the ICA is the larger of the two CCA branches. However, in the presence of neck or face malignancies, the external carotid artery (ECA) or one of its branches could be abnormally enlarged. The proximal ICA initially lays posterolateral to the ECA, then courses medial to the ECA as it advances upward. In pathological circumstances (e.g., neck cancer), the natural course, size, and overall anatomical characteristics of the ICA or the ECA can be altered and an arterial cerebral angiogram should be carefully studied. One must always be vigilant for aberrant anatomy (i.e., proatlantal persistent vessels) that could be disrupted during coil embolization, resulting in posterior circulation stroke. The site of carotid blowout should be carefully identified, and it should be determined whether it is at the CCA, ICA, ECA, or one of the

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branches. The endovascular treatment varies according to the location of the arterial injury. The ECA or branches of the ECA can be endovascularly sacrificed without impunity and the need for further testing. If the site of carotid injury is at the CCA or ICA, further evaluation is needed, including the presence of collateral blood supply from the ECA and the contralateral and posterior circulation. A balloon test occlusion (BTO) should always be done before CCA or ICA sacrifice. If the patient passes the BTO, the CCA or ICA can be sacrificed; otherwise, an endovascular or bypass reconstruction procedure is an alternative.

Periprocedure Medications Systemic heparinization is administered during the endovascular procedure because of the risk of intraprocedural thrombus formation. A weight-based intravenous bolus of heparin aimed at an activated coagulation time of 250–300 seconds may limit thromboembolic complications. Heparin should be administered once the active bleeding of the carotid artery has been stopped. For carotid artery reconstruction with stenting, dual antiplatelet therapy with aspirin (325 mg daily) and clopidogrel (75 mg daily) is prescribed to prevent platelet aggregation on the stent that can result in the formation of an intraluminal thrombus during or after the stenting procedure (see carotid artery stenting and angioplasty chapters).

Specific Technique and Key Steps 1. Carotid occlusion via coil embolization (Fig. 39.1, Video 39.1). a. After obtaining femoral artery access using modified Seldinger technique, a 6 or 8 French (F) sheath is placed within the femoral artery. b. A guide catheter is then advanced into the aorta over a curved wire (0.035-inch angled Glidewire, Terumo). c. The guide catheter is then navigated into the CCA over a 4–5F intermediate diagnostic catheter, such as a Vitek (Cook Medical) or Berenstein catheter (Cook Medical) (Fig. 39.1, Video 39.1). d. Cerebral angiography is then performed to assess for active extravasation through the ruptured carotid artery and for contribution of the affected carotid artery to the intracranial circulation (Video 39.1). e. If technically feasible, a BTO should be performed prior to carotid artery occlusion (see Chapter 9). f. A microcatheter is then placed distal to the desired site of occlusion (Video 39.1). g. Under roadmap guidance, occlusion can be performed either with liquid embolic agent, coils, or a combination of both. h. The use of a balloon or a balloon-guide catheter is recommended to cause flow arrest to prevent intracranial migration of coils or liquid embolic agent (Fig. 39.1, Video 39.1). i. Coil embolization above and below the point of rupture is performed to create a framework for liquid embolic agents (Fig. 39.1, Video 39.1). j. Final angiographic runs should be performed to confirm carotid occlusion and to assess for complications. 2. Carotid artery stent reconstruction. The technique of carotid artery stent reconstruction for CBS is similar to carotid artery stenting for stenotic disease. Please refer to Chapters 10–12.

39  Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction

Device Selection

Pearls

The following are the common setups and devices used for endovascular treatment of CBS with coils and/or Onyx: • 6–8F sheath. • 80- to 90-cm-long 6F guide catheter. • 0.035-inch angled Glidewire. • 0.044- to 0.058-inch intermediate catheter (Sofia, MicroVention; DAC, Stryker; Navien, Medtronic; Catalyst 5, Stryker). • 0.016-inch dimethylsulfoxide (DMSO)-compatible microcatheter (e.g., Headway DUO, MicroVention; SL 10, Stryker). • 0.014-inch microwire (Synchro 2, Stryker). • Multiple size coils. • DMSO. • Onyx 18 or Onyx 34 (Medtronic). • Continuous heparinized flush.

• Indications for endovascular deconstruction management are ECA involvement, CCA/ICA lesion with tolerance of BTO, and CCA/ICA lesion with insufficient time to perform BTO. • When CBS presents as a life-threatening hemorrhage, carotid sacrifice should be quickly undertaken to achieve hemostasis without previous occlusion testing. • The most common complication of endovascular arterial occlusion is cerebral ischemia. BTO is mandatory when possible. However, the incidence of delayed ischemic events in patients who pass the BTO is 20%. • Reconstructive treatment, such as stenting, allows preservation of blood flow through the carotid artery. However, these techniques pose a risk for acute thromboembolism because of the inherently thrombogenic nature of stents. • If a combination of coil(s) and Onyx is used, first use multiple coils to significantly decrease flow followed by the Onyx injection. This will reduce the risk of inadvertent intracranial embolization of Onyx (Fig. 39.1, Video 39.1). • The proximal and distal ends of the diseased artery should be covered by the embolization material to prevent collateral flow and recanalization of the lesion.

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VII  Head and Neck Embolization

Case Overview

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CASE 39.1 Carotid Artery Blowout

• A 55-year old male with laryngeal carcinoma presented with a large mass and acute active neck bleeding. The patient also complained of subacute onset of hoarseness. On examination, a large mass at the anterior neck mass with active bleeding was noticed. Manual pressure was held for temporary hemostasis. The patient had no neurological symptoms and once he was hemodynamically stable, imaging was obtained. The patient had recently received neck radiation and chemotherapy.

• Computed tomography (CT) angiography demonstrated a large hypervascular tumor at the anterior left neck with severe mass effect and tracheal deviation. The left internal carotid artery (ICA) had active extravasation with pseudoaneurysm formation at the cervical bifurcation. The ICA was irregular and near occluded.

Fig 39.1a  Left neck tumor mass with vascular compression and trachea deviation.

Fig 39.1b  Neck CT angiogram showing acute ICA blowout and contrast extravasation.

Fig 39.1c  Artist’s illustration of carotid blowout and coil and Onyx embolization.

Fig 39.1d  Severe ICA stenosis, pseudoaneurysm and active extravasation.

39  Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction

Fig 39.1e  Adequate collateral form the right ICA and posterior circulation.

Fig 39.1f  Guide catheter at the common carotid artery, microcatheter, and balloon inflated at the ICA.

Fig 39.1g  Coils.

Fig 39.1h  Onyx.

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VII  Head and Neck Embolization

Fig 39.1i  Successful ICA and pseudoaneurysm occlusion.

Video 39.1  Emergent carotid artery blowout embolization

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39  Carotid Blowout Syndrome and Vessel Sacrifice or Reconstruction

Procedure • The patient underwent urgent cerebral angiography and endovascular takedown of the left ICA. The procedure was performed under conscious sedation through a right femoral artery approach. No heparin was administered. Manual compression on the left neck was applied until the patient was in the interventional neuroradiology suite.

Device List

Device Explanation

• Femoral artery access. – Micropuncture kit. – 8F sheath. • 0.035-inch Glidewire. • Neuron MAX 088 guide catheter (Penumbra). • 0.0165-inch Excelsior SL-10 microcatheter (Stryker). • 7 x 7 mm HyperForm balloon catheter (Medtronic). • 0.014-inch Synchro 2 microwire (Stryker). • Multiple coils. • Dimethyl sulfoxide (DMSO) (Medtronic). • Onyx (ethylene vinyl alcohol [EVOH] copolymer) 34 (Medtronic). • 8F AngioSeal percutaneous closure device.

After obtaining access on the right femoral artery, a diagnostic catheter was used to obtain cerebral angiography of the right ICA, left ICA, and vertebral artery. The left hemisphere received blood flow from the right ICA and posterior circulation. After assessing adequate collateral circulation, we decided to occlude the ICA. An 088 guide catheter was positioned at the left common carotid artery. A DMSO-compatible microcatheter and an occlusion balloon were advanced into the left ICA. The balloon was inflated to create flow arrest, and multiple coils were inserted in the ICA until near total occlusion. The balloon was deflated, and while maintaining the microcatheter in position, it was primed with DMSO and Onyx 34 was slowly injected to obliterate the pseudoaneurysm, seal the extravasation off, and finish the ICA occlusion. Postembolization carotid angiography run demonstrated complete ICA occlusion.

Tips, Tricks & Complication Avoidance • Endovascular treatment of carotid artery blowout carries several risks. Endovascular occlusion with liquid embolic agents, distal arterial occlusion, and stroke could occur. Stents are thrombogenic and instent thrombosis may complicate reconstructive procedures. • It is important to assess collateralization as a first step. This information is useful when a deconstructive procedure has to be performed.

• Embolization should be performed under proximal balloon occlusion to avoid accidental material to prevent collateral flow and recanalization of the lesion. • Proximal and distal ends of the diseased segment should be covered by the embolization material (coils and Onyx) to prevent collateral flow and recanalization of the lesion.

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Part VIII Endovascular Complications and Management

VIII

40 Complications of Neuroendovascular Interventions

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40  Complications of Neuroendovascular Interventions Jason M. Davies, Hussain Shallwani, and Leonardo Rangel-Castilla

General Description The complications of endovascular interventions for the treatment of cerebrovascular diseases can be related to the inherent risks associated with catheter angiograms and catheter-based interventions, as well as the risks that patients are exposed to secondary to technical components of specific interventions. Here we review many of the most common risks (summarized in Table 40.1) and preventive or treatment strategies (summarized in Table 40.2) for various complications that may occur during neuroendovascular interventions.

•

General Complications • Contrast-related nephropathy: Acute kidney injury secondary to contrast-induced tubular necrosis is a well-described phenomenon that can be seen shortly after the administration of iodinated contrast material. This is characterized by an increase in the creatinine level between 24 and 48 hours postprocedure, followed by normalization of the level over 3–7 days. Although contrast-induced acute kidney injury is usually benign, in rare circumstances, dialysis may be required.28 • Risks related to conscious sedation/general anesthesia: Cardiovascular and respiratory complications as well as reactions to anesthetic agents are some of the known risks associated with general anesthesia. The risks can be minimized by the use of conscious sedation. As with general anesthesia, cardiovascular and respiratory functions must be closely monitored throughout the duration of the procedure to reduce the incidence of adverse events. Judicious use of sedative and analgesic agents and titration of these agents to the patient’s condition can help to avoid problems with oversedation, such as hypoventilation and hypercapnia. Reversal agents should be readily available in such cases. • Risks associated with radiation: Radiation-induced alopecia is the most common radiation-related concern and is typically a dosedependent phenomenon. It can manifest as patches of hair falling out in the days to weeks following intensive treatment. Typically, this is self-limiting, and the hair will regrow in time. With higher doses, patients may suffer skin burns. Radiation-induced malignancies may also occur in a more delayed time frame, sometimes years later. To avoid such complications, prolonged procedures benefit from dosetracking systems that measure the skin dose for the patient and help the physician assess when it may be appropriate to reposition the X-ray sources to distribute the dose over wider areas.

Access Site Complications • Access site hematoma (Fig. 40.1, Video 40.1): Hematomas are relatively common at access sites, with risk factors including body habitus, anticoagulant, thrombolytic, or antiplatelet use, and choice of puncture site. Hematomas may develop at the time of access, for instance, if there are multiple punctures, if the back-wall technique is used, or because of failure of hemostatic closure at the completion of the procedure. Hematoma risk may be mitigated with routine use of ultrasound for access, use of smaller gauge needles for initial access, and use of more superficial sites, such as the radial artery. Hematomas may present as apparent bruising under the skin, fullness in the surrounding tissues, with pain, and in extreme cases, with hypotension and bradycardia. Management of hematomas begins with control of bleeding by application of direct pressure. For superficial sites, pressure is usually sufficient, but for persistent bleeds or largebore punctures, a vascular surgery consultation may be required for

•

•

•

•

direct suture repair or placement of a covered stent over the vessel wall defect. Retroperitoneal hematoma: The greatest risk for retroperitoneal hematoma comes from a high puncture site for femoral access. Many of the same risk factors previously noted apply here, and routine use of ultrasound or prepuncture fluoroscopy will minimize these risks. Typically, the puncture should be made beneath the equator of the femoral head and an angiographic run of the groin area should indicate that the puncture site is below the inferior epigastric artery, which courses beneath the inguinal ligament and serves as a landmark for entry into the retroperitoneal space. Often there are no overt signs of a retroperitoneal bleed, so patients may lose several units of blood prior to presentation. Hypotension and tachycardia are often the presenting signs. The hematoma can be confirmed with computed tomography (CT) of the abdomen and pelvis. Resuscitation with fluids or blood and use of vasopressors are usually adequate for management, but if there is a large volume or persistent loss of blood, placement of a covered stent for obliteration of the opening may be necessary. Pseudoaneurysm: Weakness in the arterial wall after access has been obtained can lead to partial-thickness dilation of the vessel. Most pseudoaneurysms present as a palpable mass and are best evaluated with ultrasound imaging and a vascular surgery consultation. Many pseudoaneurysms will spontaneously thrombose and the mass will dissipate over time. Some lesions may require a thrombin injection performed by a vascular surgeon; enlarging and high-flow lesions may require repair with open surgery or covered stenting. Arterial dissection: Dissection at the access site is generally discovered during routine angiographic runs through the sheath after access has been obtained. If an intimal flap is noted, it is best to obtain a vascular surgery consultation. Non-flow-limiting dissections may not require intervention and can be managed with aspirin. If flow limitation is noted, stenting may be required. Nerve injury: Poor localization of the vessel, like in a patient with large body habitus or calcified vessels, can make arterial puncture difficult. Medialization of the needle could lacerate or puncture the nerve and lead to pain, numbness, or paresthesias. This is often managed conservatively and will improve with time, although poorly tolerated pain may be successfully managed with gabapentin or pregabalin. Use of ultrasound and careful palpation, especially in patients with difficult anatomy, may help to reduce such injuries. Infection of the access site or abscess formation: Infections may present as superficial erythema, drainage, or a palpable mass. Ultrasound imaging can be helpful to elucidate the relationship of masses to the artery and can exclude the presence of a pseudoaneurysm. Patients with large body habitus or preexisting superficial infections are particularly prone to infectious complications. In such patients, alternate access sites should be considered. Superficial infections can be successfully managed with oral antibiotics and should be closely monitored for abscess formation. An abscess should be managed aggressively. A vascular surgery consultation should be obtained as surgical drainage and debridement are often required. Wound healing is often an issue for groin abscesses because it is difficult to keep the area clean and dry.

General Procedural Complications • Vasospasm: Catheter manipulation can irritate vessels and cause them to constrict. If the vasospasm is flow-limiting, the catheter should be withdrawn to avoid ischemic complications. Vasodilators, such as verapamil, should be slowly infused to relax the vessels

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VIII  Endovascular Complications and Management before proceeding with the procedure. In peripheral locations, such as when accessing or navigating the radial artery, spasm also responds to topical vasodilators, such as nitroglycerine paste, and to systemic analgesics. • Vessel perforation (Fig. 40.2, Video 40.2): Wire perforations can result from several issues. A build-up of tension in microcatheter systems can result in an uncontrolled release of energy, causing microcatheters or microwires to lurch forward. This is especially problematic during aneurysm access as the microcatheter can frequently catch at the orifice, and the release of pressure can result in a wire or catheter puncturing an already fragile aneurysm dome. If vessel perforation is suspected, often it is best to leave the devices in place and obtain a guide catheter run to assess for active extravasation. If none is observed, the interventionist may have some time to prepare additional devices to manage the perforation. Ideally, the anticoagulation effect should be reversed with protamine in the case of systemic heparinization. Hemostasis must then be assured at the site of perforation. This can be achieved with a balloon or embolic materials. If the perforation happens during coiling or liquid embolic administration, the embolization procedure is continued within the subarachnoid space as the catheter is withdrawn into the aneurysm, thus plugging the perforation. Balloons may also be useful for controlling flow at the site of the perforation. If necessary, a second access site is obtained, and the balloon microsystem is advanced to the site of the perforation. The balloon is inflated, and the perforating device is withdrawn under conditions of flow stasis. Inflation is maintained for 3 minutes at a time, with flow restored and confirmatory runs obtained to assess for further bleeding. This is repeated until no further extravasation is seen. • Distal thromboembolism (Fig. 40.3, Video 40.3): Emboli may result from numerous procedural issues, and the management approach differs with each. Injected emboli include air and clot, both of which may occur with improper flush technique. For cerebral angiography, the double-flush technique or the use of heparinized saline pressure bags is essential to keep catheters clear. Emboli can also result from catheter manipulation of calcified vessels, causing calcific fragments to shower the distal vasculature. For patients in whom there is known or suspected calcification, particularly in the aortic arch, care should be taken to choose an access route that minimizes vessel manipulation in terms of introducing devices and minimizes the number of times the arch is traversed by selecting vessels in order as they branch off the aorta. Most distal emboli are asymptomatic, apparent only with findings of restricted diffusion on postprocedural magnetic resonance imaging. However, if a patient becomes acutely symptomatic or flow limitation is noted during the course of an angiogram, mechanical thrombectomy or intra-arterial thrombolytic infusion may be warranted.

Complications at Closure • Failure of closure device: Failure of closure devices is frequently noted in the acute phase, manifesting as arterial bleeding or the formation of a rapidly expanding hematoma at the access site. It may also manifest in a delayed fashion as a retroperitoneal hematoma or a groin hematoma. Regardless of presentation, manual compression at the puncture site is applied. Clamp-type pressure devices may be useful in such settings and pressure is typically applied for 20–30 minutes, although longer time frames may be prudent in cases of anticoagulant administration and/or access with a large-gauge needle. • Access site thrombosis or distal thromboembolism: Thrombosis at the puncture site may occur when the vessel caliber does not permit forward flow of blood around the arterial sheath. For this reason, it is essential to document distal pulses prior to access so any change in pulse can prompt further investigation. Thrombosis at the access site or distally is usually best managed by a vascular surgeon, so asking for help (a vascular surgery consultation) early is essential. If the interventionist suspects access site issues at the time of access, it may

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be prudent to ask for a consultation while the procedure is ongoing in case salvage maneuvers are possible while the sheath is in place.

Complications of Mechanical Thrombectomy • Vessel dissection with a stent retriever: Intimal damage with stent retriever use is a relatively rare occurrence and can result in flow limitation or hemorrhage. After each stent retrieval, signs of dissection should be assessed. A non-flow-limiting dissection may not require any further intervention, but antiplatelet medication may be indicated to prevent further thrombosis as a result of an exposed vessel wall. However, in the event of a flow-limiting dissection, the focus of the case must shift to stenting the dissected segment open. If no hemorrhage is noted, antiplatelet medication is instituted, and the interventionist introduces an appropriate microsystem. The dissection must be successfully crossed with a clear connection from true lumen to true lumen, as evidenced by intravascular opacification seen on a distal microcatheter injection. The stent is then advanced and deployed across the site of injury. Often, this can be successfully accomplished, along with intravenous administration of glycoprotein (GP) IIb/IIIa inhibitors, which can then be converted to dual antiplatelet medications after the acute phase of the intervention. Care should be taken to avoid unnecessary angioplasty in a dissected vessel out of concern for rupturing the already weakened vessel wall. If hemorrhage is noted, balloon tamponade proceeded by stenting is a reasonable approach. In cases where thrombolytics have been administered, vessel sacrifice may be necessary. • Distal thromboembolism (Fig. 40.3, Video 40.3) With manipulation and restoration of flow, clots may fragment and migrate to more distal locations. Depending on their locations, it may be advisable to pursue these clots, for instance when an internal carotid artery terminus clot migrates to an M1 or M2 location. However, the relative risks and benefits of additional clot retrieval need to be assessed throughout the procedure because very distal lesions may present a risk of perforation or perforator avulsion that is greater than the risk of stroke. Frequently, after the conversion of a large-vessel occlusion to a small-vessel occlusion, patients clinically improve, despite distal thromboembolism. If the decision is reached to pursue distal emboli, we favor judicious use of stent retrievers and prefer an aspiration-only technique to avoid avulsion-type injuries. • Vasospasm: Vessel manipulation may result in vessel reactivity. This can limit flow, thus increasing thrombotic risks but may also make navigation of vessels more fraught. If vasospasm is noted, calciumchannel blockers can help to relax the vessel. This medication should be given time to take effect before proceeding with the intervention to avoid further vessel injury. • Device detachment or misplacement: Despite rigorous regulatory oversight, device malfunctions, such as inadvertent disconnection of stent retrievers, may occur. Dealing with these unforeseen events requires quick judgment. Although it is sometimes possible to retrieve stents by withdrawing them with oversized stent retrievers deployed within the stent or snares to grasp them from outside, these are difficult maneuvers that may cause further vessel injury. If the device is in a large vessel and obstructing flow, reasonable attempts should be made to retrieve. However, in cases where devices are deployed in smaller vessels or they are not flow-limiting, it is reasonable to leave them in place and to institute GP IIb/IIIa therapy and thereafter convert to dual antiplatelet therapy. • Symptomatic intracerebral hemorrhage (Fig. 40.2, Video 40.2): Vessel perforation and reperfusion hemorrhage may both result in symptomatic hemorrhage. If extravasation is noted at the time of the procedure, it should be controlled with balloon tamponade or vessel sacrifice, as previously described. The severity of symptoms and size of the hematoma will guide further management. Small hemorrhages associated with modest symptomatology may best be managed with

40  Complications of Neuroendovascular Interventions administration of hypertonic solutions, whereas larger lesions may require surgical evacuation. Early intervention and close surveillance are key. • Subarachnoid hemorrhage: Avulsion of perforating vessels because of the traction placed on vessels during mechanical thrombectomy can result in subarachnoid blood. If extravasation is noted at the time of the procedure, it should be controlled with balloon tamponade or vessel sacrifice as previously described. However, if evidence of such bleeding is only noted on postoperative CT scans, the condition can usually be managed conservatively. Serial scans are appropriate, but it is not usually necessary to treat the patient with the full subarachnoid protocol, as with aneurysmal hemorrhage.

Complications of Aneurysm Embolization (Coiling or FlowDiversion) • Coil migration or loss: When a coil is deployed in an unintended location, there are a few reasonable strategies. Coil retrieval may be attempted and is often feasible with the use of a stent retriever deployed along the length of the distal coil, allowing the coil to be dragged back into the guide catheter and retrieved. Snares may also be useful for retrieval, but small vessels and difficulty grasping the coil make stent retrievers our preferred method. If retrieval does not succeed, stabilizing the coil in place with deployment of a permanent stent is the preferred option. If both methods fail, surgical retrieval must be considered. • Rupture of aneurysm (Fig. 40.4, 40.5, 40.6 Video 40.4, 40.5, 40.6): Intraoperative rupture must be managed swiftly and in such a way that the patient does not suffer hemorrhagic and ischemic complications from the procedure. Ideally, anticoagulation should be reversed with protamine in the case of systemic heparinization. Hemostasis can be achieved with a balloon or coiling materials. If the perforation happens during coiling, the embolization is continued within the subarachnoid space as the catheter is withdrawn into the aneurysm, thus plugging the perforation. Balloons may also be useful for controlling flow. If necessary, a second access site is obtained, and the balloon microsystem is advanced to the perforation site. The balloon is inflated, and the perforating device is withdrawn under conditions of flow stasis. Inflation is maintained for 3 minutes at a time, with flow restored and confirmatory angiographic runs obtained to assess for further bleeding. This process is repeated until no further extravasation is seen. • Migration of flow-diversion device (distally or into the aneurysm) (Fig. 40.7, Video 40.7): Flow diverter migration can be a difficult problem to manage depending on where the device lands. If migration only uncovers the neck of the aneurysm, it is usually a straightforward matter of telescoping additional devices to fully cover the aneurysm ostium. However, if device migration results in deployment within the dome of a large aneurysm, there are several management options. If the microsystem has maintained distal access, it is usually possible to use the previously described telescoping stent maneuver to span the aneurysm neck. If distal access is lost, the options depend on regaining distal access. If it is possible to get wire access across the stent, the telescoping maneuver is preferred. If not, every effort should be made to retrieve the flow diverter, usually with a snare-type device. • Aneurysm regrowth or rupture (late complication or failure of treatment) (Fig. 40.8, Video 40.8): Coil compaction and aneurysm regrowth are known issues with endovascular treatments. Each case is individual, but options include recoiling, use of balloon or stent adjuncts for neck remnants, use of flow diverters, or surgical clip ligation. • Risks with dual antiplatelet therapy (if a stent is used): The current generation of intraluminal devices typically requires 6–12 months of dual antiplatelet administration to prevent intraluminal thrombus

from forming as the stent heals into place. However, in neurologically impaired or elderly patients, this may cause any number of medical complications, ranging from epistaxis to severe gastrointestinal bleeds to subdural hematomas. A thorough risk-benefit discussion should be had with patients and their care providers before stopping these medications early. Usually, antiplatelet agents are only withdrawn early in life-threatening circumstances, and if possible, a single agent, usually aspirin, should be continued.

Complications of Arteriovenous Malformation (AVM) Embolization • Rupture of AVM: Premature embolization of arterial or venous channels with a change in flow dynamics may result in periprocedural rupture of AVMs. The critical decision in such cases is whether further embolization would stop the bleeding. In cases where bleeding is from a single vessel that could be occluded as a result of the embolization already performed, it may make sense to continue to embolize. If rupture is the result of the draining vein occluding, it is often not possible to control bleeding from a single pedicle. We favor placement of a ventriculostomy and surgical resection in most cases. • Proximal reflux of embolic material: Careful attention must be paid to reflux as it may occlude vessels feeding eloquent regions of the brain and cause symptomatic strokes. It is often useful to define how much reflux will be tolerated during a procedure and to agree to abort the embolization procedure if that limit is exceeded. When reflux is noted, forward pressure on the injection syringe is simply stopped. Usually this is sufficient to arrest the flow of embolic material. It is not necessary to immediately withdraw the microcatheter because frequently a modest amount of reflux can create a plug that allows for successful subsequent embolization. • Glue embolization in normal vasculature or the parent vessel: If glue is moving into unintended areas, it is best to immediately stop the embolization process to assess the consequences. Awake patients can be queried to determine the functional impact of the unintended embolization. If neurologic deficits are noted, mechanical thrombectomy may be attempted with stent retrievers and suction devices, as would be done for an occlusive stroke. Densely embolized vessels may not respond to these techniques, but subocclusive embolic material may be retrieved. • Cementing (gluing) of the distal catheter tip (Fig. 40.9, Video 40.9): Aggressive embolization and reflux of glue around the catheter can make catheter withdrawal quite difficult. Although the use of detachable tip catheters mitigates this issue, it is important to have strategies to deal with stuck catheters. Most catheters will yield to persistent pressure. It can be useful to place a clamp on the microcatheter to hold constant pressure, pulling and reclamping every few minutes until the catheter releases. This can sometimes take up to 1 hour. If the catheter does not release after application of pressure, it may be necessary to cut the microcatheter at the groin. The microcatheter is stretched as much as possible and cut flush with the skin so that it recoils into the soft tissues. Pressure is held to obtain hemostasis, and the patient is placed on antiplatelet agents while the remaining portion of the microcatheter endothelializes into the vessel.

Complications of Carotid Artery Stenting • Plaque rupture and thromboembolic complications: Embolic protection is an essential part of carotid stenting, but there are certain cases where it fails or is infeasible. Ruptured plaque containing embolic material may lodge in distal filters or in the intracranial vasculature. If within the filter, a suction catheter can be introduced and used to clear the filter prior to retrieval. If the material is noted intracranially, the case becomes a typical mechanical thrombectomy case, with the

475

VIII  Endovascular Complications and Management difference being that stent retrievers may not be withdrawn through the carotid stent unprotected, meaning that they must be completely sheathed within the suction catheter or the guide catheter tip must be advanced beyond the stent to avoid entanglement of the devices. • Hemodynamic instability: This frequently occurs with angioplasty at the carotid bulb. Prophylactic administration of glycopyrrolate may be used to minimize this risk. If the patient becomes bradycardic or symptomatic during the procedure, the balloon should be deflated. In some patients, it may be necessary to perform several brief balloon inflations to adequately open the vessel without overly stressing the heart. • Hyperperfusion hemorrhage: Aggressive blood pressure management at the time of carotid stenting is essential to prevent a state of hyperperfusion. Cerebral vessels may be maximally dilated and have lost autoregulatory control as a result of chronic ischemia. Sudden reperfusion at high blood pressures can result in cerebral dysfunction or vessel rupture. Once the carotid lesion has been opened, we favor

the use of nicardipine to keep the systolic pressure below 140 mmHg to minimize this risk. • Myocardial infarction: Routine electrocardiography and troponin blood testing every 8 hours overnight postprocedure is useful for detecting cardiac issues and preventing more severe consequences. If abnormalities arise, a cardiologist is consulted swiftly. • Other extracranial vessel stenting complications include dissection, occlusion, and stent migration (Fig. 40.10, 40.11, Video 40.10, 40.11).

Complications of Intracranial Angioplasty and Stenting • Vessel rupture or hemorrhage: same as above. • Vessel dissection: same as above. • Thromboembolism: same as above.

Table 40.1  Incidences of complications associated with endovascular procedures Incidence Complications at access and closure

476

• Access site/groin hematoma • Pseudoaneurysm formation • Retroperitoneal bleed • Closure device failure • Arteriovenous fistula formation

• 0.5%–14% • 2.0%–8.0% • 0.1%–0.7% • 1.1% • < 1.0%

Mechanical thrombectomy

Toddler/child

• Vessel perforation (with wire or stent retriever) • Distal thromboembolism • Vasospasm • Device detachment/misplacement • Symptomatic intracerebral hemorrhage • Subarachnoid hemorrhage

• 0.6%–4.9% • 1.0%–12.5% • 3.0%–23.0% • 0.7%–3.9% • 3.6%–9.3% • 0.6%–5.5%

Embolization (coiling/flow diversion) of aneurysms

Toddler/child

• Ischemic complications (coiling) • Hemorrhagic complications (coiling) • Coil migration • Aneurysm regrowth (coiling) • Aneurysm perforation (coiling) • Ischemic complications (flow diversion) • Aneurysm rupture/postprocedure hemorrhage (flow diversion) • Delayed intraparenchymal hemorrhage (flow diversion) • Flow-diversion device malfunction

• 2.8%–11.0% • < 1.0% • 1.0%–2.0% • 16.0% • 2.4%–4.7% • 1.6%–6.0% • 0.6%–4.0% • 2.0%–3.0% • 2.5%–15.1%

Embolization of AVMs

Toddler/child

• Ischemic complications • Hemorrhagic complications • Periprocedural arterial perforations • Perioperative morbidity • Perioperative mortality

• Variable (multifactorial) • Variable (multifactorial) • 5.2% • 3.0%–14.0% • 0.0%–4%

Carotid artery stenting

Toddler/child

• Periprocedural stroke • Hemodynamic instability • Hyperperfusion hemorrhage

• 4.1%–7.1% • 2.3% • 0.2%–2.2%

Intracranial angioplasty and stenting

Toddler/child

• Hemorrhagic complications • Thromboembolism/Ischemic complications

• 0.6%–4.5% • 0.0%–10.3%

1,2,3,4 4 4

5

4

6,7,8,9,10,11,12 7,8,9,10,11,12 7,8,9,10,11,12

12 7,8,9,10,11,12 7,8,9,10,11,12

13,14,15

13

14

15

16 17 17 18 19

20

21,22

22

23,24

23

23,25

26,27 26,27

40  Complications of Neuroendovascular Interventions Table 40.2  Techniques to prevent and/or treat complications—Summary Complications at access and closure

• Access site/groin hematoma, retroperitoneal hematoma, pseudoaneurysm formation ◦ Use of ultrasound for access and careful palpation for artery ◦ Use of smaller gauge needles for initial access ◦ Use of more superficial sites, such as the radial artery • Arterial dissection/thrombosis ◦ Alternate access sites in case of diseased vessel General procedural complications

• Vasospasm ◦ Withdrawal of catheter ◦ Injection of vasodilator • Air/clot embolus ◦ Proper flushing of catheters ◦ Continuous flushing of catheter

• Infection of the access site/abscess formation ◦ Alternate access sites in case of superficial infection ◦ Preprocedure antibiotics • Failure of closure device ◦ Manual compression • Arterial dissection/rupture ◦ Careful sizing of arterial sheath (undersize to vessel diameter) ◦ Aspiration before injection ◦ Alternate access site in case of diseased/calcified vessels

• Vessel perforation ◦ Use of fluoroscopic roadmap to advance wire (avoid blind maneuvering)

Mechanical thrombectomy

• Vessel injury, dissection or perforation (with wire or stent-retriever) ◦ Intracranial stenting for dissection ◦ Balloon tamponade in case of hemorrhage ◦ Intraprocedure balloon occlusion or vessel sacrifice in case of large hemorrhage

• Distal thromboembolism ◦ Thrombectomy for distal thrombus/embolus (if feasible) ◦ Intraarterial administration of tissue plasminogen activator or GP IIb/IIIa inhibitors

• Device detachment/misplacement ◦ Snare retrieval of detached/misplaced device

Embolization (coiling/flow-diversion) of aneurysms

• Coil migration/coil loss ◦ Retrieval using stent-retriever or snare devices ◦ Stenting or surgical removal of coil • Rupture of aneurysm ◦ Balloon/coil occlusion for hemostasis

• Migration of flow-diversion device (distally/into the aneurysm) ◦ Telescoping of flow-diverter device with additional devices ◦ Snare retrieval of flow-diverter device • Aneurysm regrowth/rupture (late complication/failure of treatment) ◦ Re-coiling, stent-assisted coiling, flow diversion, surgical clipping, and other options (as applicable per case)

Embolization of AVMs

• Rupture of AVM—secondary to premature embolization of arterial/ venous channels with change in flow dynamics ◦ Careful planning of pedicle/venous embolization ◦ Staged embolization • Proximal reflux of glue or embolization in normal vasculature/parent vessel ◦ Gradual/controlled injection

• Cementing (gluing) of distal catheter tip ◦ Use of detachable tip catheters ◦ Persistent graduated pressure on cemented (glued) catheter ◦ Cutting the catheter at the access site with manual compression for closure and subsequent dual-antiplatelet therapy until endothelialization

Carotid artery stenting

• Plaque rupture and thromboembolic complications ◦ Distal filter protection ◦ Flow arrest with proximal balloon inflation ◦ Stent retriever or aspiration thrombectomy for distal thromboembolism

• Hemodynamic instability ◦ Prophylactic administration of glycopyrrolate ◦ Successive brief balloon inflations for angioplasty • Hyperperfusion hemorrhage ◦ Strict blood pressure control postprocedure (e.g., SBP