Flow diversion beyond the circle of Willis: endovascular aneurysm treatment in peripheral cerebral arteries employing a novel low-profile flow diverting stent

Abstract

BackgroundFlow diversion (FD) has emerged as superior minimally invasive therapy for cerebral aneurysms. However, aneurysms of small peripheral vessel segments have not yet been adequately treatable. More specifically, currently established devices necessitate large microcatheters which impede atraumatic maneuvering. The Silk Vista Baby (SVB), a novel flow diverter, offers the as yet unique feature of deliverability via a 0.017 inch microcatheter. This study reports our first experience with the SVB in challenging intracranial vessels employing a vessel-specific tailored microcatheter strategy.Materials and methods25 patients (27 aneurysms) were prospectively included. A total of 30 SVBs were employed, predominantly targeting demanding aneurysms of the anterior communicating artery complex. The efficacy of the FD was assessed using two-dimensional vector-based perfusion and conventional digital subtraction angiography (DSA) after implantation and at the first follow-up at 3 months. The first follow-up was available in 22 patients.ResultsAll devices were implanted without technical or clinical complications. Eleven treatments were performed using the recommended Headway 17. In 14 interventions the even more maneuverable Excelsior SL10 was used, which was previously tried and tested for safety ’in vitro’ as an alternative delivery system. Aneurysmal influx was strongly reduced after implantation. All parent vessels remained patent. 17/27 aneurysms were completely occluded at first follow-up (∼2.7 months), 6/27 aneurysms showed decreased influx or delayed washout and one remained unchanged. In three cases follow-up DSAs are remaining.ConclusionsSVB provides enhanced controllability in vulnerable segments beyond the circle of Willis. Smaller variants (2.25 mm and 2.75 mm) can safely be implanted via the superiorly navigable Excelsior SL10. Hence, the SVB represents the next evolutionary step in minimally invasive treatment of cerebral aneurysms.

Flow diversion in challenging vascular anatomies: the use of low profile stent retrievers for safe and accurate positioning of the microcatheter

“…FD has become a highly efficient standard treatment for most intracranial sidewall aneurysms (Dmytriw et al, 2019). However, the delivery of the extra-saccular endovascular implants to sometimes quite peripherally located vascular targets may prove particularly challenging, especially when encountering significant proximal supra-aortic elongation along with unfavorable distal junction angles at the transition from the proximal to the distal segments of the cerebral vessels (Schob et al, 2019a;Martínez-Galdámez et al, 2019). In those cases, exchange maneuvers are required to eventually provide a sufficiently large lumen for device delivery in combination with stable access to the target segment (Chapot et al, 2013).…”

“…Neurovascular stenting using low profile flow diverter stents (FDS) or braided aneurysms stents composed of a less dense mesh for treatment of especially peripheral and small cerebral aneurysms has gained significant importance during recent years (Möhlenbruch et al, 2017;Voigt et al, 2017;Schob et al, 2019a;Martínez-Galdámez et al, 2019;Aydin et al, 2017;Iosif & Biondi, 2019). Extra-aneurysmal flow diversion immediately reduces aneurysmal hemodynamic force by redirecting the physiological blood flow along the natural axis of the parent vessel, away from the aneurysmal orifice.…”

“…However, microcatheters bearing approval for FD implantation necessarily possess comparatively large inner diameters (0.021″-0.027″) and exhibit considerable catheter stiffness. As a consequence their maneuverability is limited and frequently causes increased mechanical force along the microcatheter during probation of distal vessel segments (Schob et al, 2019a). Therefore, primary probation of the vascular target with the catheter intended for FDS implantation may prove to be very difficult or even futile in demanding vascular anatomies.…”

Review of current intracranial aneurysm flow diversion technology and clinical use

“…38 55 Another important anatomical consideration is that the tortuous anatomy of distal vessels markedly foreshortens the FD on deployment. 44 This, coupled with the relatively large and rigid delivery systems of the previous generation FD, can challenge the proper placement of the device, which may require the use of multiple devices for adequate neck coverage, increasing the risk of ischemic complications. 56 Previous authors have recommended to slightly oversize FD selection for highly tortuous vessels to account for device foreshortening 44 ; however, this can lead to lengthening of the FD, decreasing its metal coverage and increasing porosity, thus decreasing its effectiveness.…”

Advances in endovascular aneurysm management: flow modulation techniques with braided mesh devices

“…There were no technical or clinical complications. 61 Follow-up (average 2.7 months postoperatively) was available for 24/27 aneurysms: 17 (70.8%) aneurysms were completely occluded; 6 (25%) showed decreased influx; and one (4.1%) showed no haemodynamic change. The authors feel that enhanced visibility and radial force likely reduce non-opening issues associated with SILK and SILK+.…”