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Advanced Neurology Woven Endobridge embolization: Indications and innovation

Flow diversion emerged as a paradigm shift in treating resheathed and repositioned. Serial control angiograms
wide-neck and bifurcation aneurysms. Rather than direct are performed following the deployment, demonstrating
intrasaccular embolization, flow diversion aimed to divert progressively rapid cessation of blood flow within the
flow away from the aneurysm resulting in delayed thrombosis aneurysm, starting distally and progressing toward the
and endothelialization of the parent vessel wall. Devices aneurysm neck. Complete cessation of intra-aneurysmal
such as the Pipeline Flex embolization device (PED) achieve blood flow is noted within minutes of placement, and
flow diversion with lower porosity and approximately 30% complete occlusion of an aneurysm can be confirmed at
higher metal coverage . The Honeycomb Microporous 8 weeks . Endothelialization of the parent vessel by the
[10]
[15]
Covered Stent features a stent covered by a polyurethane growth of neo-endothelium within the recessed concavity
film that allows for greater flow-diverting properties than a of the embolization device has been noted . Thus, the
[16]
traditional stent . While these devices are promising, dual WEB embolization device combines stent-assisted coiling
[11]
antiplatelet therapy is still required. and flow diversion features while minimizing the need for
The Woven Endobridge (WEB) embolization device long-term antiplatelet therapy.
is an intrasaccular flow diverter designed to divert flow at 2. Clinical trials and ongoing investigations
the interface between the aneurysm neck and the parent
artery . The device deploys a double-layer (DL) braided The WEB embolization device has demonstrated success
[12]
oblate nitinol mesh within the aneurysm sac, which self- in pre-clinical trials. Several ongoing clinical trials are
expands to conform to the aneurysm wall and span the investigating the device’s effectiveness and safety, while
aneurysm neck. As the therapy focuses on stabilization and exploring its suitability to various types of intracranial
coverage of the aneurysm neck, the device is designed for aneurysms. A total of 11 trials using the device have been
both wide-neck and bifurcation aneurysms. The device may registered (National Library of Medicine), of which six
also be a single layer (SL) or a single-layer sphere (SLS) . have been completed (Table 1). Of these six trials, five have
[13]
The inner and outer layers of the mesh are held together by results available, while one does not have results available
radiopaque markers, which allow direct visualization of the currently. Of the remaining five registered studies, one was
device within the aneurysm with X-ray-based techniques. withdrawn, one was terminated, one is under recruiting
The thrombogenicity of the WEB device is comparable phase, one is not currently recruiting, and one is under
to that of intrasaccular coils, but the radiopaque marker unknown status. A summary of clinical trials and their
at the luminal surface of the mesh is not thrombogenic, current statuses are found in Table 1.
except where an endoluminal construct is indicated for
better support. Long-term antiplatelet therapy is usually A prospective, multicenter, and observational study
unnecessary in most patients . conducted with ten French neurointerventional centers,
[14]
collectively called French Observatory (NCT01975233),
The WEB embolization device mesh is advanced up primarily looked at the post-procedure occlusion durability
to the aneurysm using a VIA catheter, usually with a of the aneurysms treated with WEB devices (Table 2) .
®
[17]
transfemoral approach. The microcatheter containing the The WEBCAST study (NCT01778322) evaluated the safety
mesh is positioned within the fundus of the aneurysm and efficacy of WEB devices in wide-neck bifurcation
and deployed within the aneurysm. An angiogram is aneurysms, mostly unruptured (Table 2) . A cumulative
[18]
performed immediately after deployment (Figure 1). If population study was performed with the patients from
positioning is favorable, the device can be detached and the French Observatory trial (NCT01975233) and the
remains within the aneurysm. If not, the device can be WEBCAST trial (NCT01778322) . In the cumulative
[19]
study, treatment with WEB was successfully performed
A B in 96.5%. At 1 year, complete aneurysm occlusion was
observed in 56.0%, neck remnant in 26.0%, and an
aneurysm remnant in 18.0%, of which 2.0% worsened
since the procedure. At 1 year, mortality was 3.9%, with
three deaths unrelated to an aneurysm or treatment and
one related to a partially thrombosed aneurysm .
[19]
The WEBCAST-2 was later designed to corroborate
further the high degree of safety and efficacy demonstrated
Figure 1. Angiogram of anterior communicating artery aneurysm. by WEBCAST and French Observatory studies . The
[20]
(A) Placement of WEB device in aneurysm with early stasis. (B) Final
positioning of WEB device in aneurysm dome. study had a comparable protocol to WEBCAST, with a
Abbreviation: WEB: Woven Endobridge. few changes. At 1 year, complete occlusion was achieved

Volume 2 Issue 3 (2023) 2 https://doi.org/10.36922/an.293