Transradial access for embolization of cerebral aneurysms with the woven EndoBridge device: Case series and review of the literature

Abstract

Background

Transradial access is an increasingly utilized route for neurointerventions with benefits of lower rates of access site complications, earlier patient mobilization and increased patient satisfaction over transfemoral interventions. There is limited data on deployment of the Woven EndoBridge (WEB) via transradial access. We report a case series of consecutive patients undergoing cerebral aneurysm embolization with the WEB device via transradial biaxial access.

Methods

A database of neuroendovascular procedures was queried for consecutive aneurysm embolization procedures involving the WEB device and intended via the transradial approach between August 2019 and July 2020. Patient demographics, radiological aneurysm characteristics and procedure details were recorded and statistically evaluated. Google Scholar and Pubmed were searched for previous reports of transradial WEB embolization.

Results

Ten aneurysms were treated in ten patients. All aneurysms were treated with successful WEB deployment. Nine of the ten aneurysms were successfully treated via transradial biaxial access. One aneurysm required conversion to transfemoral access. There were no clinical complications and no morbidity or mortality.

Conclusions

Transradial embolization of cerebral aneurysms with the WEB device is safe and feasible with low rates of access failure or complications.

Introduction

There is growing evidence of feasibility, safety and benefit for transradial access for both cerebral angiography and neurointerventions. Published case series and reviews have demonstrated such for aneurysm coil embolization, thrombectomy, angiography and embolization via flow diversion.^1–4 However, there are limited reports of transradial cerebral aneurysm embolization with the Woven EndoBridge (WEB) device (Microvention, Aliso Viejo, CA, USA). With its first clinical use in 2011 the WEB device is the first intrasaccular flow disruptor designed to treat wide necked bifurcation aneurysms.⁵ The device’s safety and efficacy have been studied in five major clinical trials.^6–10 Manufacturer recommendations and expert opinion recommend triaxial access for placement of the WEB device.¹¹,¹²

Here we review the previous limited published experience with transradial WEB embolization and report our own experience, including our technical success rate, complications and technical nuances. Special focus is placed on the feasibility of lower profile biaxial systems for WEB embolization.

Methods

Prospectively maintained data was retrospectively reviewed for those patients undergoing embolization with the WEB device. This was narrowed to patients with attempted or completed transradial access for placement of the WEB device. Characteristic data including patient demographics, aneurysm size and location, catheter constructs, treatment device and clinical and radiographic outcomes were then extracted.

The initial setup for all procedures consisted of a right radial approach with a short 6 Fr low profile arterial sheath (Glidesheath, Terumo, Tokyo, Japan). An intraarterial cocktail of 2500 units of heparin and five to ten milligrams of verapamil was then infused as an antispasmolytic and to lower the incidence of radial artery occlusion. A biaxial system consisting of a 130 centimeter 5 Fr Select Sim 2 (Penumbra, Alameda, CA, USA) through either a 6 Fr 95 or 105 centimeter Benchmark support catheter (Penumbra, Alameda, CA, USA) was used to access the target vessel. The biaxial system was taken up over either a 150 or 180 centimeter 0.035” Glidewire (Terumo, Tokyo, Japan). When the target vessel was not preferentially selected by the Glidewire the Sim 2 would then be formed in the aorta. The preferred technique positioned the Sim 2 with the tip in the descending aorta and the curve centered over the ascending aorta ostia. If this technique failed, the Sim 2 shape would be formed over the Glidewire against the aortic valve. The target vessel was then catheterized in standard fashion with the Sim 2 prior to bringing the Benchmark up over the Sim 2 into the distal cervical or petrous portion of the internal carotid artery. The Sim 2 and Glidewire were then removed, allowing for embolization with the appropriate Via microcatheter (Microvention, Aliso Viejo, CA, USA) directly through the Benchmark.

Six of seven of unruptured patients were on dual antiplatelet regimens prior to embolization with aspirin and either clopidogrel or prasugrel in anticipation of potential need for stent assistance. The efficacy of the P2Y12 inhibitor was assessed with VerifyNow (Instrumentation Laboratory, Bedford, MA, USA) pre-procedurally and doses were adjusted accordingly. All procedures were performed under general anesthesia. All but two patients had their P2Y12 inhibitors discontinued immediately post-operatively. Most unruptured patients were continued on aspirin in the immediate post-embolization period. No patient with a ruptured aneurysm was started on antiplatelets prior to the procedure. All patients were dosed with intravenous heparin intra-procedurally starting with 50 units/kilogram for those patients with unruptured aneurysms and 25 units/kilogram for those patients with ruptured aneurysms.

Google Scholar and Pubmed were both queried for previous published experience and summarized. The study was approved by the local institutional review board with a waiver of informed consent given the retrospective analysis of de-identified data.

Results

Ten transradial WEB placements were attempted in ten patients. The characteristics of the patients and procedures can be found in Table 1. 60% of the patients were female. The average age was 64.3 +/− 10.4. 70% of the aneurysms were unruptured. All aneurysms were anterior circulation with five middle cerebral artery bifurcation aneurysms, one internal carotid artery terminus aneurysm and four anterior communicating artery aneurysms (Figure 1). All four anterior communicating artery aneurysms were approached from the left based on dominant A1 inflow to the aneurysm. There was on label use of the WEB in all cases based on size, location and either neck width or dome-to-neck ratio. Nine procedures were completed via the right transradial approach. The technical transradial success rate was 90%.

Table 1.

Transradial WEB table.

Age	Sex	Aneurysm location	Aneurysm height (mm)	Aneurysm width (mm)	Aneurysm status	Vessel access	Guide catheter(s)	Microcatheter	WEB device	Access conversion	Notes
69	M	R MCA	8.5	8	Unruptured	R radial	6 Fr Benchmark	Via 27	WEB SL 9 mm × 7 mm	No	None
40	F	R MCA	5	4.5	Unruptured	R radial	6 Fr Benchmark	Via 21	WEB SL 5 mm × 4 mm	No	None
65	F	L MCA	4	4.5	Unruptured	R radial	6 Fr Benchmark	Via 21	WEB SL 5 mm × 3 mm	No	None
66	M	A comm	10	8.5	Unruptured	R radial	6 Fr Benchmark	Via 27	WEB SL 10 mm × 6 mm	No	None
56	F	A comm	7	4.5	Ruptured	R radial	6 Fr Benchmark	Via 21	WEB SL 5 mm × 4 mm	No	Failed corking WEB at neck; WEB tilted into aneurysm dome and aneurysm had to be coiled
64	M	A comm	7.5	6	Ruptured	R radial	6 Fr Benchmark	Via 21	WEB SL 7 mm × 5 mm	No	None
76	F	L MCA	4	4.5	Ruptured	R radial	6 Fr Benchmark	Via 21	WEB SL 4 mm × 3 mm	No	None
63	F	A comm	5.5	7	Unruptured	R radial	6 Fr Benchmark	VIA 21	WEB SL 7 mm × 5 mm	No	None
67	M	R ICA	8	4	Unruptured	R radial	6 Fr Benchmark	Via 21	WEB SL 4 mm × 3 mm	No	None
77	F	L MCA	4	5.5	Unruptured	R femoral	NeuronMAX6 Fr Sofia	Via 21	WEB SL 5 mm × 3 mm	Yes	None

M: male; F: female; MCA: middle cerebral artery; A comm: anterior communicating; ICA: internal carotid artery; R: right; Fr: French; WEB: Woven EndoBridge.

Figure 1.

(a) Approach view to a large unruptured anterior communicating artery aneurysm with the Benchmark in the cervical carotid. (b) Pre embolization oblique working view with the Benchmark advanced to the cavernous carotid. (c) Post embolization oblique working view.

One procedure performed in a patient with an acute left common carotid take off, nearly parallel to the aorta, and a left middle cerebral artery aneurysm required conversion to transfemoral access when distal purchase with the Benchmark could not be achieved. The transfemoral catheter setup consisted of a triaxial system with a NeuronMAX (Penumbra, Alameda, CA, USA) and a 6 Fr 115 cm Sofia intermediate catheter (Microvention, Aliso Viejo, CA, USA).

For one transradial deployment a triaxial system was initially deployed because of perceived distal carotid tortuosity on approach. This consisted of a 125 centimeter 5 Fr Sofia catheter (Microvention, Aliso Viejo, CA, USA) through a 95 centimeter 6 Fr Benchmark. However lack of distal purchase with the Sofia catheter meant the Via microcatheter did not have the length to reach the target anterior communicating artery aneurysm and the longer Sofia had to be removed. Ultimately, the embolization was completed with a biaxial system directly through the Benchmark. Therefore, all successful transradial embolizations were completed through a biaxial system.

There were no clinical complications. The neurologic morbidity and mortality were 0%. There was one non-access technical complication where an undersized WEB was attempted to be “corked” at the neck of an anterior communicating artery aneurysm but post-deployment shifted into the aneurysm dome so as to no longer cover the whole of the neck of the aneurysm. The aneurysm was re-accessed with an Excelsior SL-10 microcatheter (Stryker, Fremont, CA, USA) through the Benchmark and the embolization completed with coils without complication.

One WEB deployment at a middle cerebral artery aneurysm was completed with the assistance of a Scepter XC balloon (Microvention, Aliso Viejo, CA, USA) to protect an M2 branch. This was completed with both the balloon and microcatheter through the standalone Benchmark catheter.

A literature search revealed eight previously reported cases of transradial WEB embolization. These appear in two case reports and a single case series of various embolization devices, including the WEB, via the transradial approach,^13–15 The case series appears to include a patient from one of the previous case reports. Seven of the patients were treated via a triaxial system. The sole patient treated via a biaxial system was a posterior circulation basilar tip aneurysm. The details of the previous cases can be found in Table 2.

Table 2.

WEB lit review table.

References	Age	Sex	Aneurysm location	Aneurysm height (mm)	Aneurysm width (mm)	Aneurysm status	Vessel access	Cath setup	WEB device	Notes
P Boghal, et al13	63	F	Basilar	6.5	4.5	Ruptured	R radial	Biaxial	WEB SL 6 mm × 4 mm	None
Al Saiegh, et al.14Mouchtouris, et al15	53	F	A comm	10	9	Unruptured	R radial	Triaxial	WEB SL 9 mm × 4 mm	None
Mouchtouris, et al.15	57	F	MCA	5.9	3.5	Unruptured	R radial	Triaxial	WEB SLS 4 mm	None
Mouchtouris, et al15	58	F	ICA	4	3.6	Unruptured	R radial	Triaxial	N/A	Unable to deploy WEB; aneurysm coiled
Mouchtouris, et al15	63	F	P comm	5.6	4.5	Unruptured	R radial	Triaxial	WEB SL 7 mm × 4 mm	None
Mouchtouris, et al15	48	F	ICA	3.5	3.5	Unruptured	R radial	Triaxial	WEB SL 5 mm × 4 mm	None
Mouchtouris, et al15	58	F	Basilar	6.5	5.4	Unruptured	R radial	Triaxial	WEB 8 mm × 4 mm	None
Mouchtouris, et al.15	65	F	MCA	2.9	5.3	Unruptured	R radial	Triaxial	WEB 5 mm × 4 mm	None

F: Female; M: Male; A comm: Anterior communicating; MCA: Middle cerebral artery; ICA: Internal carotid artery; R: Right; WEB: Woven EndoBridge.

Discussion

Our experience provides further evidence of the feasibility and safety of embolization with the WEB device via a transradial approach and represents the largest case series to date of such.

Concurrent with previous reports of success with biaxial systems via transradial approach for flow diversion our experience also provides support for the adequacy of transradial biaxial systems for the deployment of complex embolization devices including the WEB.¹⁶ Even for certain left internal anterior circulation interventions the long stretch of catheter through the subclavian and brachiocephalic appears to provide added support as compared to transfemoral access. In our limited experience distal access with the support catheter can be key to successful biaxial embolization with petrous or even cavernous positioning ideal (Figure 1).

We had reasonable success with the transradial approach with one access failure and conversion to transfemoral access. As in our case of access failure, certain acute takes offs of the left common carotid artery are known predictors of transradial access difficulty and failure.¹⁶ Further studies of anatomic variants as related to transradial failure is needed.

All cerebral angiography and neurointerventions by the lead author are now performed with a right radial preference. Alternative access is largely only considered pre-procedure for certain anatomic findings such as arteria lusoria or radial artery occlusion. For posterior circulation interventions with a strongly dominant left vertebral artery the left radial artery is our vessel of choice for access.

This study has a number of limitations. Namely amongst them are its report of a single operator’s experience at a single institution and its relatively small sample size. However, it does represent the largest case series to date for transradial WEB embolization. Further studies are needed to know the true success rate for successful WEB deployment via the transradial approach. In addition while several patients have undergone additional post embolization angiography with demonstrated patent radial arteries, we do not typically perform post-procedure sonography to assess for clinically silent radial artery occlusion. Some clinically silent access site complications may have been missed.

Conclusion

Transradial embolization of cerebral aneurysms with the WEB device is both feasible and safe including with lower profile biaxial systems.