COMMENTARY

Commentary: Introduction: History and Development of Flow Diverter Technology and Evolution Downloaded from https://academic.oup.com/neurosurgery/article/86/Supplement_1/S11/5675133 by guest on 01 October 2021 reatment of intracranial has cating segment have motivated the use of flow Alejandro Enriquez- been transformed over the last decade diversion beyond the circle of Willis. Currently, Marulanda, MD T with the development of several endovas- there are few reported case series for distal 1 Ajith J. Thomas, MD cular devices. In this review article, there that have shown promising results is a detailed discussion of the history, devel- with infrequent complications from perforator Neurosurgical Service, Beth Israel Dea- opment, and technical aspects of flow diversion coverage.5-7 Technically, these aneurysms are coness Medical Center, Harvard Medical technology. It is interesting how this technology challenging to treat with conventional FDs due School, Boston, Massachusetts has evolved so rapidly over time and has proven to the small luminal diameter and also due Correspondence: that there is still room for innovation in the to the more acutely angled configuration of Ajith J. Thomas, MD, treatment of cerebrovascular diseases. The first the distal parent vessel, and new technology Neurosurgical Service, series of flow diverters (FD) aimed to achieve will be needed to overcome these difficulties. Beth Israel Deaconess Medical Center, Harvard , complete occlusion of aneurysms intraproce- The novel device Silk Vista Baby (SVB; BALT, 110 Francis Street, durally, sometimes deploying more than one Montmorency, France) was developed for the Boston, MA 02215, USA. device over the aneurysm neck to achieve treatment of aneurysms located in small cerebral Email: [email protected] immediate aneurysm exclusion. This, however, vessels ranging from 1.5 to 3.5 mm and was at the expense of higher risk of small currently is the only FD that can be delivered Received, August 4, 2019. 2 Accepted, August 6, 2019. branch occlusion and subsequent infarction. through a 0.017-inch microcatheter. This device Published Online, December 16, 2019. Later, when new evidence showed that the FD consists of 48 nitinol (roughly 50% nickel) stents acted as a scaffold for neoendothelial- braided wires (porosity 50 to 60% with 36 to Copyright C 2019 by the ization and that aneurysm occlusion occurred 51 pores per mm2), designed with a blue surface Congress of Neurological Surgeons in a delayed fashion, which usually reaches its and an inner platinum core (which enhances zenith 12 months post-FD deployment,3 the device radiopacity and visibility during the inter- practice was changed to using a single device vention). A recent study demonstrated the safety for aneurysm neck coverage with satisfactory of this device in which there was no evidence results. of procedure-related complications.6 Smaller and It is worthwhile to mention that initial dual more flexible devices will probably set a new antiplatelet (DAPT) plays a critical role standard for flow diversion in small intracranial in the safety of flow diversion as it prevents vessels. the development of thrombotic complications. Further research and innovation would be Notably, patients should be tested for clopi- needed to push frontiers and determine the dogrel resistance before the FD deployment to safety and efficacy of FD on ruptured aneurysms, determine if adjustments of dosage or switching small aneurysms, distal circulation aneurysms, to a different agent such as ticagrelor should be posterior circulation aneurysms, nonsaccular performed as it has shown that it decreases the aneurysms, previously treated aneurysms, and rates of these types of ischemic complications.4 other cerebrovascular diseases such as carotid As mentioned in the article, the development cavernous fistulas. of new FD with special coating that reduces the thrombogenicity of the stent while it is still not endothelized, such as the Shield technology for Disclosures the Pipeline Embolization Device (Medtronic), Dr Thomas is a guest editor of the Flow Diversion will be promising and may represent in the future for Treatment Supplement and an alternative to DAPT, which also has a low but was on the DSMB of the SCENT trial for SURPASS. Outside of publication in this supplement, Dr Enriquez- important risk of hemorrhagic complications. Marulanda has no personal, financial, or institutional interest The optimal treatment outcomes of internal in any of the drugs, materials, or devices described in this carotid aneurysms up to the communi- article.

NEUROSURGERY VOLUME 86 | NUMBER 1 | JANUARY 2020 Supplement | S11 ENRIQUEZ-MARULANDA AND THOMAS

REFERENCES 5. Ravindran K, Enriquez-Marulanda A, Kan PTM, et al. Use of flow diversion for the treatment of distal circulation aneurysms: a multicohort study. World Neurosurg. 1. Kühn AL, Gounis MJ, Puri AS. Introduction: history and development of flow 2018;118:e825-e833. diverter technology and evolution. Neurosurgery. 2020;86(1 suppl):S3-S10. 6. Schob S, Hoffmann K-T, Richter C, et al. Flow diversion beyond the circle of Willis: 2. Siddiqui AH, Abla AA, Kan P, et al. Panacea or problem: flow diverters in the endovascular aneurysm treatment in peripheral cerebral employing a novel treatment of symptomatic large or giant fusiform vertebrobasilar aneurysms: clinical low-profile flow diverting stent. J Neurointerv Surg. published online: May 14, 2019 article. JNeurosurg. 2012;116(6):1258-1266. (doi: 10.1136/neurintsurg-2019-014840). 3. Gupta R, Ogilvy CS, Moore JM, et al. Proposal of a follow-up imaging strategy 7. Cagnazzo F, Cappucci M, Dargazanli C, et al. Treatment of distal anterior following Pipeline flow diversion treatment of intracranial aneurysms. JNeurosurg. cerebral artery aneurysms with flow-diverter stents: a single-center experience. Am J published online: July 1, 2018 (doi: 10.3171/2018.2.JNS172673). Neuroradiol. 2018;39(6):1100-1106.

4. Adeeb N, Griessenauer CJ, Foreman PM, et al. Use of platelet function testing Downloaded from https://academic.oup.com/neurosurgery/article/86/Supplement_1/S11/5675133 by guest on 01 October 2021 before pipeline embolization device placement: a multicenter cohort study. Stroke. 2017;48(5):1322-1330.

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