Multicentre study indicates WEB flow disrupters can safely be used in sidewall aneurysms

Nimer Adeeb

As per the findings of a multicentre, retrospective study, use indications for the Woven EndoBridge (WEB) intrasaccular flow disruption device (Microvention/Terumo) can be safely extended to include sidewall intracranial aneurysms.

The study’s authors detail in Radiology that no significantly different outcomes were associated with this off-label use of the device—as compared to its US Food and Drug Administration (FDA)-approved use in wide-neck bifurcation aneurysms. “The correct characterisation of the sidewall aneurysm location, neck angle and size is crucial for successful treatment and lower retreatment rate,” Nimer Adeeb (Louisiana State University Health Sciences Center, Shreveport, USA) and colleagues write.

To compare angiographic and clinical outcomes between the treatment of sidewall and bifurcation aneurysms, the authors conducted an analysis of the WorldWideWEB Consortium—a synthesis of retrospective databases spanning from January 2011 to June 2021 at 22 academic institutions across the Americas, Europe and Australia—to identify patients with intracranial aneurysms treated using the WEB device. The consortium was co-led by Adeeb and Adam Dmytriw (Massachusetts General Hospital, Boston, USA).

Across 671 patients, a total of 683 intracranial aneurysms met the study’s inclusion criteria, Adeeb and colleagues report. Those aneurysms were divided into bifurcation and sidewall groups—and the bifurcation group included 572 aneurysms (median patient age=61 years; 69.8% female), while the sidewall group included 111 aneurysms (median patient age=62 years; 78.4% female). Propensity score matching (PSM) was then performed, resulting in 91 bifurcation and sidewall aneurysm pairs.

Detailing the results of the study, the authors state that no significant difference was observed in deployment success, complication rates, median length of procedure, or use of adjunctive coil placement, between the two groups. They add that immediate adequate WEB aneurysm occlusion was higher in the sidewall group compared with the bifurcation group (66.1% vs 43.3% of aneurysms, respectively) but, at the last follow-up, no significant difference was observed in adequate WEB aneurysm occlusion rates (89% vs 85%). Retreatment was needed in 7.2% of aneurysms in the bifurcation group versus 10.9% in the sidewall group, they also note.

“The correct characterisation of the sidewall aneurysm location, neck angle and size is crucial for successful treatment and lower retreatment rate.”

The majority of patients had an independent functional status at discharge, as per the modified Rankin Scale (mRS) and—while complications were higher in the bifurcation group than the sidewall group (8.4% vs 2.7% of procedures, respectively)—there was no significant difference observed in terms of haemorrhagic complications, technical complications and mortality. There was also no recorded incidence of aneurysm rerupture in the study sample. Following PSM, no significant difference was observed in rates of long-term aneurysm occlusion, retreatment, or complications, between the two groups.

“Currently, several endovascular options are available for treatment of intracranial aneurysms, and more are likely to be available in the near future,” Adeeb and colleagues write. “Some of those treatments may ultimately be a better fit for certain aneurysm locations, including sidewall aneurysms, compared with WEB. However, the goal of this study is to address the growing trend of off-label use of WEB for treatment of sidewall aneurysms compared with bifurcation aneurysms in a large, matched cohort. Future studies should focus on comparing the clinical and angiographic outcomes for the WEB device versus flow-diverting stents for treatment of sidewall aneurysms by using matched cohorts.”

Adeeb is also the lead author for a recent retrospective cohort analysis that homed in on bifurcation aneurysm data from the WorldWideWEB Consortium to compare treatment outcomes using the WEB device across various aneurysm locations. A total of 572 aneurysms were included, and the researchers note the rate of adequate aneurysm occlusion was significantly higher for basilar tip (91.6%) and internal carotid artery (ICA) bifurcation (96.7%) aneurysms, and lower for anterior cerebral artery (ACA) bifurcation (71.4%) and anterior communicating artery (AComA; 80.6%) aneurysms.

Writing in the Journal of NeuroInterventional Surgery, Adeeb and colleagues conclude: “To our knowledge, this is the most extensive study to date that compares the treatment of different intracranial bifurcation aneurysms using the WEB device. Basilar tip and ICA bifurcation aneurysms showed significantly higher rates of aneurysm occlusion than other locations.”


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