The Pipeline embolization device for treatment of intracranial aneurysms

Abstract

Flow diversion is a new endovascular technique developed for treatment of intracranial aneurysms. It is based on stent-induced modification of blood flow within and around an aneurysm inflow zone, leading to gradual intra-aneurysmal thrombosis and subsequent atrophy, while preserving flow into the parent vessel and perforating branches. Flow-diversion technique is well-suited for the treatment of large, giant, wide-necked, and fusiform intracranial aneurysms because it does not rely on endosaccular packing with coils but rather on the strategy of placing a stent across the aneurysm “neck” or across the diseased segment of a vessel in case of a fusiform aneurysm. Over time, neointimal endothelium covers the flow diverter such that it becomes incorporated into the parent vessel wall and occludes the aneurysm from the circulation, effectively repairing the diseased parent vessel segment. This report describes in detail the Pipeline embolization device (ev3-Covidien, Irvine, California, USA), its mechanism of action and deployment technique, and reviews the pertinent literature regarding safety, efficacy and potential risks and complications associated with the use of this flow diverter.

Keywords::

• endovascular treatment
• flow diversion
• intracranial aneurysms
• Pipeline embolization device

Acknowledgements

The authors thank N Aronoff, MLS, at the Kaleida Health Libraries for providing literature search and reference retrieval assistances and PH Dressel, BFA, for assistance with preparation of the illustrations and DJ Zimmer for editorial assistance (both at University at Buffalo Neurosurgery).

Financial & competing interests disclosure

TM Dumont, JL Eller and GC Sorkin report no financial relationships. LN Hopkins receives grant/research support from Toshiba; serves as a consultant to Abbott, Boston Scientific, Cordis, Micrus and Silk Road; holds financial interests in AccessClosure, Augmenix, Boston Scientific, Claret Medical, Endomation, Micrus and Valor Medical; holds a board/trustee/officer position with Access Closure and Claret Medical; serves on Abbott Vascular's speakers' bureau; and has received honoraria from Bard, Boston Scientific, Cleveland Clinic, Complete Conference Management, Cordis, Memorial Health Care System and the Society for Cardiovascular Angiography and Interventions (SCAI). EI Levy receives research grant support, other research support (devices) and honoraria from Boston Scientific and research support from Codman & Shurtleff, Inc. and ev3/Covidien Vascular Therapies; has ownership interests in Intratech Medical Ltd. and Mynx/Access Closure; serves as a consultant on the board of Scientific Advisors to Codman & Shurtleff, Inc.; serves as a consultant per project and/or per hour for Codman & Shurtleff, Inc., ev3/Covidien Vascular Therapies and TheraSyn Sensors, Inc.; and receives fees for carotid stent training from Abbott Vascular and ev3/Covidien Vascular Therapies. EI Levy receives no consulting salary arrangements. All consulting is per project and/or per hour. M Mokin has received an educational grant from Toshiba. AH Siddiqui has received research grants from the National Institutes of Health (co-investigator: NINDS 1R01NS064592-01A1; not related to present device review) and the University at Buffalo (Research Development Award); holds financial interests in Hotspur, Intratech Medical, StimSox, Valor Medical and Blockade Medical; serves as a consultant to Codman & Shurtleff, Inc., Concentric Medical, Covidien Vascular Therapies, GuidePoint Global Consulting, Penumbra, Inc., Stryker Neurovascular and Pulsar Vascular; belongs to the speakers' bureaus of Codman & Shurtleff, Inc. and Genentech; serves on National Steering Committees for Penumbra, Inc. 3D Separator Trial and Covidien SWIFT PRIME Trial; serves on an advisory board for Codman & Shurtleff and Covidien Vascular Therapies; and has received honoraria from American Association of Neurological Surgeons' courses, Annual Peripheral Angioplasty and All That Jazz Course, Penumbra, Inc. and from Abbott Vascular and Codman & Shurtleff, Inc. for training other neurointerventionists in carotid stenting and for training physicians in endovascular stenting for aneurysms. AH Siddiqui receives no consulting salary arrangements. All consulting is per project and/or per hour. KV Snyder serves as a consultant and a member of the speakers' bureau for Toshiba and has received honoraria from Toshiba. He serves as a member of the speakers' bureau for and has received honoraria from ev3 and The Stroke Group.

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Endovascular coiling, with or without balloon or stent assistance, has become the preferred treatment modality for most intracranial aneurysms.

• Large, giant, wide-necked and fusiform intracranial aneurysms remain particularly challenging, with low aneurysm occlusion rates and significant morbidity and mortality associated with surgical or endovascular treatment.

• Flow diversion represents a paradigm change in endovascular aneurysm treatment, whereby the diseased segment of the parent vessel is reconstituted with a high metal, low-porosity stent that diverts flow away from the aneurysm, leading to aneurysm thrombosis, shrinkage and neointimal parent vessel remodeling.

• Because flow diversion does not rely on endosaccular filling of the aneurysm with coils, the size of the aneurysm sac or neck is less relevant to its effectiveness; therefore, it seems a well-suited technique for the treatment of large, giant or fusiform aneurysms for which no optimal treatment alternative exists.

• Notwithstanding the limitations and potential complications associated with flow diversion, it offers a promising new technique in the field of endovascular neurosurgery.

Notes