Low-Profile Intra-Aneurysmal Flow Disruptor WEB 17 versus WEB Predecessor Systems for Treatment of Small Intracranial Aneurysms: Comparative Analysis of Procedural Safety and Feasibility

Lessons learned from 12 years using the Woven Endobridge for the treatment of cerebral aneurysms in a multi-center series

Intrasaccular flow disruption with the Woven Endobridge (WEB) has become a well-established endovascular technique for the treatment of intracranial aneurysms. This study presents our 12-year experience with the WEB and evaluates its evolving indications, procedures, and outcomes. A consecutive series of 324 aneurysms treated with WEB between 2011 and 2023 at three neurovascular centers was retrospectively analyzed and the study group was divided into four treatment periods. Uni- and multivariate analyses were performed to evaluate factors associated with technical success, thromboembolic complications, and angiographic outcome. The mean aneurysm size was 7.0 ± 3.6 mm and decreased during the study period, while the proportion of atypical sites for WEB implantation increased. WEB implantation was technically successful in 96.0%, and the ratio of WEB width to dome width increased during the study period, indicating oversizing. The neurological complication rate was 4.9% (1.5% major, 3.4% minor) and the mid-term complete occlusion rate was 60.6% (81.9% adequate occlusion), with no statistical differences in either outcome measure between the study periods. In multivariate analyses, the use of WEB 17 was associated with increased technical success (HR: 7.4, 95%CI: 2.4-23.6, p<0.01), whereas ruptured aneurysm status (HR: 2.5, 95%CI: 1.0-6.0, p=0.04) and the use of additional stents (HR: 4.8, 95%CI: 1.6-14.4, p<0.01) predicted thromboembolic complications. Appropriate oversizing of the WEB favored mid-term complete occlusion (HR: 10.5, 95%CI: 1.3-83.3, p=0.03). The results suggest an expansion of the indications for WEB implantation and highlight the importance of oversizing for treatment efficacy.

CLinical EValuation of WEB 17 device in intracranial aneuRysms (CLEVER): 1-year effectiveness results for ruptured and unruptured aneurysms

BACKGROUND

The Woven EndoBridge (WEB) device is designed to treat wide-necked bifurcation aneurysms. The WEB 17 is the latest iteration and can be delivered through a 0.017″ microcatheter. The CLEVER study demonstrated that WEB 17 is safe and effective for providing protection against bleeding or rebleeding at 1 month and 1 year.

OBJECTIVE

To evaluate angiographic stability at 1 year.

METHODS

The CLEVER study was a prospective multicenter study conducted in 17 European centers, involved 163 subjects, comprising 60 ruptured and 103 unruptured aneurysms. Independent assessment of 1-year follow-up imaging was incorporated into the study design.

RESULTS

Aneurysm diameters ranged from 2.0 to 9.2 mm, with 95.7% being broad-based (dome-to-neck ratio <2). Follow-up imaging at 1 year was completed for 146 out of 163 subjects (89.6%) and evaluated by an independent core laboratory. The primary efficacy endpoint of adequate occlusion without re-treatment at 1 year was achieved for 120 (82.2%) of all subjects. At 1 year, the adequate occlusion rate was 86.5% for ruptured aneurysms (73.1% complete occlusion) and 82.4% for unruptured aneurysms (57.1% complete occlusion). The overall re-treatment rate at 1 year was 2.6% (4/152), with 3.1% (3/97) for unruptured aneurysms and 1.8% (1/55) for ruptured aneurysms CONCLUSION: Delivery of the WEB 17 via 0.017 inch catheters represents a significant evolution of the WEB design. The results of CLEVER presented here demonstrate that it maintains the same efficacy as previous generations of WEB.

Endovascular Treatment of Bifurcation Aneurysms with the Woven EndoBridge: Product Features and Selected Results of Off-Label Use

Treatment for wide-neck bifurcation cerebral aneurysms (WNBAs) is widely performed by endovascular treatment as well as open surgical clipping. However, due to factors such as the shape and size of the aneurysms, as well as the anatomical features of surrounding branch vessels, there are some cases in which simple coiling or conventional adjunctive techniques, such as balloon-assisted or neck bridge stent-assisted coiling, are not sufficient to achieve a satisfactory cure. Against this backdrop, the device known as the Woven EndoBridge (WEB) (MicroVention, Aliso Viejo, CA, USA) was developed and can be deployed directly into the aneurysm for treatment. Over a decade has passed since its development, and it is now used in many countries worldwide. This review provides insights into the evolution of the WEB device from its development to the date of this writing, highlighting the unique features of the device and its treatment indications. Additionally, it discusses the posttreatment course, perspectives on recurrence and retreatment, imaging assessments, and potential off-label use based on numerous studies primarily conducted in Europe and the USA.

CLinical EValuation of WEB 17 device in intracranial aneuRysms (CLEVER): procedural, 30-day and 1-year safety results for ruptured and unruptured aneurysms

BACKGROUND

Intrasaccular flow disruption is an endovascular approach for the treatment of wide-neck aneurysms and, more specifically, wide-neck bifurcation aneurysms, which are challenging to treat with previously developed technologies. The Woven EndoBridge (WEB) device has demonstrated its efficacy and safety, for both unruptured and ruptured aneurysms.

METHODS

The CLEVER study was an observational, multicenter, prospective study conducted in 17 European investigational sites using the WEB 17 device, for the treatment of ruptured and unruptured aneurysms. The study objective was to provide safety and efficacy data on the WEB 17 device in the treatment of wide-neck bifurcation aneurysms. Imaging results were assessed independently by a Corelab and adverse events adjudicated by a Clinical Event Adjudicator. This analysis reports procedural results and safety at 30 days and 12 months.

RESULTS

A total of 163 patients (mean age 58.1 years; 68.1% women) with 103 unruptured aneurysms and 60 ruptured aneurysms were enrolled. Most aneurysms were located on the anterior communicating artery (ACom) (37.4%) or the middle cerebral artery (MCA) bifurcation (30.1%). Aneurysm widths ranged from 2.0-9.2 mm, and the mean sac width was 5.0 mm. The WEB procedure was successfully completed in 163 patients (100%). At the 12-month follow-up, major stroke events occurred in 3 of 163 patients (1.8%), and no device-related mortality was observed.

CONCLUSION

Endovascular treatment of ruptured and unruptured wide-neck bifurcation aneurysms using WEB 17 is safe, with a low complication rate and no device-related mortality. In particular, none of the ruptured aneurysms bled again up to 1 year of follow-up.

TRIAL REGISTRATION NUMBER

NCT03844334.

Aneurysm Treatment with Woven EndoBridge-17: Angiographic and Clinical Results at 12 Months from a Retrospective, 2-Center Series

BACKGROUND AND PURPOSE

This retrospective, 2-center study investigated the feasibility, safety, and efficacy at 12-month follow-up of the treatment of ruptured, unruptured, and recurrent intracranial aneurysms using the latest generation of the Woven EndoBridge (WEB) device, the WEB-17 system.

MATERIALS AND METHODS

Aneurysms treated with WEB-17 were extracted from the databases of 2 neurovascular centers. Patients, aneurysm characteristics, complications, and clinical and anatomic results were analyzed.

RESULTS

From February 2017 to May 2021, two hundred twelve patients with 233 aneurysms (181/233, 77.7%, unruptured-recurrent, and 52/233, 22.3%, ruptured) were included. High treatment feasibility (95.3%) was reported and was similar in ruptured aneurysms (94.2%) and unruptured-recurrent aneurysms (95.6%) (P = .71) and in typical (95.4%) and atypical (94.7%) locations (P = .70), but it was lower in aneurysms with an angle between the parent artery and main aneurysm axis of ≥45° (90.2%) compared with those with an angle of <45° (97.1%) (P = .03). Global mortality and morbidity were 1.9% and 3.8% at 1 month, respectively, and 4.4% and 1.9% at 12 months, respectively. One-month morbidity (P = .02) and mortality (P = .003) were higher in the ruptured group (10.0% and 8.0%, respectively) compared with unruptured-recurrent group (1.9% and 0.0%, respectively). Overall adequate occlusion (complete occlusion and neck remnant) was 86.3%. The percentage of adequate occlusion was higher (P = .05) in the unruptured-recurrent group (88.5%) compared with the ruptured group (77.5%).

CONCLUSIONS

The WEB-17 system showed high feasibility for ruptured and unruptured aneurysms, typical and atypical locations, and some aneurysms with an angle of ≥45°. As the most recent generation device, the WEB-17 also demonstrates high safety and good efficacy.

Trends of Expanding Indications of Woven EndoBridge Devices for the Treatment of Intracranial Aneurysms: A Systematic Review and Meta-analysis

PURPOSE

Woven EndoBridge (WEB) was introduced for the endovascular therapy of wide-neck intracranial aneurysms. The safety and efficacy have been evaluated through several meta-analyses. However, these reviews did not cover the expanding indications in detail. Therefore, we aimed to show the changing trends for intracranial aneurysm treatment using the WEB device.

METHODS

A systematic review and meta-analysis was conducted with PubMed, Embase, and Cochrane databases. We searched for studies that reported baseline characteristics of aneurysms and the WEB devices, which had treated more than 20 aneurysms consecutively. The pooled proportions of aneurysm indications and used WEB device types were obtained. To evaluate the changing indications for the treated aneurysm size, including the neck diameter, a trend line and linear regression model was measured.

RESULTS

A total of 27 cohorts were included encompassing 1831 aneurysms treated with the WEB. A total of 86% were used in the four major locations as on-label indications (middle cerebral artery bifurcation; 34%, anterior communicating artery; 26%, basilar tip; 18%, internal carotid artery terminus; 7%). Among off-label indications, the most common location was the posterior communicating artery (8%), followed by the anterior cerebral artery including the pericallosal artery (6%). The median aneurysm size and neck diameter was 7 mm and 4.6 mm, respectively. The WEB device has been used for the treatment of smaller aneurysms than the initial indication. Also, the proportion for ruptured aneurysm treatment was increased up to 15%.

CONCLUSION

The mechanical and technical development of the WEB resulted in expanding the indications for the treatment of intracranial aneurysms. The off-label indications accounted for 14% in total and an increasing number of small aneurysms are treated with WEB devices. Moreover, the proportion for ruptured aneurysm treatment was currently increased up to 14% more than in the beginning.

Treatment of Proximal Posterior Inferior Cerebellar Artery Aneurysms by Intrasaccular Flow Disruption: A Multicenter Experience

BACKGROUND AND PURPOSE

Treatment of PICA aneurysms can be technically challenging by either surgical or endovascular means. Our aim was to report our preliminary experience with intrasaccular flow disruption using the Woven EndoBridge (WEB) for the treatment of proximal PICA aneurysms.

MATERIALS AND METHODS

Sixteen PICA aneurysms treated with the WEB at 3 institutions were retrospectively reviewed. Baseline patient and aneurysm characteristics, procedural specifics, clinical outcomes, and angiographic results were evaluated.

RESULTS

All aneurysms were located at the proximal, anteromedullary segment of the PICA. Seven aneurysms were ruptured. The median aneurysm size was 3.9 mm (range, 2-12 mm), and all aneurysms were wide-neck. WEB deployment failed in 1 case due to WEB protrusion in a small PICA aneurysm. Additional stent implantation was required for 2 aneurysms to improve intra-aneurysmal WEB positioning. One patient developed a partial posterior cerebral artery territory infarction with transient hemianopsia. Intraoperative rerupture of a ruptured aneurysm could be immediately stopped by WEB deployment due to intrasaccular stasis; however, it might have contributed to a slight disability of the patient. At last angiographic follow-up, 12/15 aneurysms (80%) were completely occluded and 3/15 (20%) had a neck remnant.

CONCLUSIONS

The preliminary results indicate that WEB treatment of proximal PICA aneurysms is feasible with a reasonable safety and efficacy profile. The advantages of intrasaccular flow disruption include preservation of the PICA, durable aneurysm occlusion, and omission of antiplatelet therapy. The low-profile WEB 17 delivery system might enable navigation to distal PICA aneurysms, which needs to be addressed further.

Long-term clinical and angiographic outcome of the Woven EndoBridge (WEB) for endovascular treatment of intracranial aneurysms

The Woven EndoBridge (WEB) is a well-established device for endovascular treatment of wide-necked bifurcation aneurysms. The objective was to evaluate the long-term angiographic outcome of the WEB and to identify factors that influence aneurysm occlusion. Patient, aneurysm and procedural characteristics of 213 consecutive patients treated with the WEB at three German tertiary care centers between 2011 and 2020 were retrospectively reviewed. Aneurysm occlusion was determined immediately after the procedure, at mid-term (≤ 12 months) and at long-term (> 12 months) follow-up. Among 182 included aneurysms (mean diameter: 7.0 ± 2.4, mean neck width: 4.3 ± 1.6 mm), 29.7% were ruptured. The novel WEB 17 was used in 41.8%, and 11.0% were treated in combination with coiling and/or stenting. Complete and adequate occlusions were observed in 101/155 (65.2%) and 133/155 (85.8%) at mid-term, respectively, and in 59/94 (62.8%) and 87/94 (92.6%) at long-term follow-up (median: 19 months), respectively. Among 92 patients available for both mid- and long-term follow-up, occlusion was stable in 72.8%, improved in 16.3% and worsened in 10.9%. There were no major recurrences leading to aneurysm remnants between mid- and long-term follow-up. Retreatment was performed in 10/155 (6.5%) during mid-term and in 1/94 (1.0%) during long-term follow-up. The WEB provides durable aneurysm occlusion at the long-term. Nevertheless, follow-up imaging is necessary to identify late recurrences that may occur in around 10%.

Stent-assisted WEB embolization: aneurysm characteristics, outcome and case report of a WEB delivered through a stent

PURPOSE

Woven Endobridge (WEB) embolization has become a well-established endovascular treatment option for wide-necked bifurcation aneurysms. The objective was to analyse cases that required additional stent-implantation.

METHODS

Images of 178 aneurysms ≤ 11 mm treated by WEB only or by WEB plus stent were retrospectively reviewed, evaluating aneurysm characteristics, procedural specifics, adverse events and angiographic results. Moreover, we report a case of a WEB delivered through a previously implanted stent.

RESULTS

Additional stent implantation was performed in 15 patients (8.4%). Baseline patient and aneurysm characteristics were comparable between both groups. A single stent was used in 12 cases and 2 stents in Y-configuration in 3. Thromboembolic complications occurred more often with stent assistance (33.3% vs. 8.0%, p = 0.002), while ischemic stroke rates were comparable between both groups (0% vs. 1.8%, p = 1.0). Six-month angiographic follow-up showed complete occlusion, neck remnants and aneurysm remnants in 73.4%, 19.4% and 7.3% after WEB only, respectively, and in 66.7%, 20.0% and 16.7% after WEB plus stent, respectively (p = 0.538). A case report shows that WEB deployment through the struts of a previously implanted standard microstent is feasible, even if a VIA 33 microcatheter is needed.

CONCLUSION

In the present study, stent-assisted WEB embolization had a comparable safety and efficacy profile compared to treatment by WEB only. However, stent-assisted WEB embolization requires long-term anti-platelet medication, which annihilates the advantages of the WEB as a purely intrasaccular device.

CLINICAL TRIAL REGISTRATION NUMBER

N/A.

Intracranial aneurysm treatment with intrasaccular flow disruption: comparison of WEB-21 and WEB-17 systems

BACKGROUND

New generations of Woven EndoBridge (WEB) devices (WEB-21 and WEB-17) are available to treat aneurysms with a width <6.5 mm. Limited comparisons between both systems exist in the literature, but mid-term efficacy has not been compared. Our study aimed to compare the indications, feasibility, and safety of both systems and to evaluate their efficacy at mid-term follow-up (12 months).

METHODS

Aneurysms treated with WEB-21 and WEB-17 were extracted from a prospective database. Patient and aneurysm characteristics, complications, and anatomical results were analyzed by an interventional neuroradiologist, independent of the procedures.

RESULTS

From June 2015 to November 2019, 87 patients with 92 aneurysms were treated with WEB-21 (38/92, 41.3%) and WEB-17 (54/92, 58.7%). WEB-21 and WEB-17 had high treatment feasibility (97.4% and 94.4%, respectively). A higher percentage of ruptured aneurysms were treated with WEB-17 (9.3%) than with WEB-21 (2.6%; p=0.03). Morbidity and mortality at 1 month were similar in both groups (no morbidity in either group, and mortality 2.7% in the WEB-21 group and 2.0% in the WEB-17 group). The rate of complete and adequate aneurysm occlusion was not significantly higher with the WEB-17 system (59.2% and 95.9%, respectively) compared with the WEB-21 (52.9% and 85.3%, respectively).

CONCLUSIONS

This study showed the high feasibility of aneurysm treatment with both the WEB-21 and WEB-17 systems. Indications were relatively similar with both devices except for ruptured aneurysms, which were more frequently treated with the WEB-17 device. Efficacy at 12 months (complete and adequate occlusions) was slightly, but not significantly, better with the WEB-17 device.

Endovascular Treatment of Small and Very Small Intracranial Aneurysms with the Woven EndoBridge Device

BACKGROUND AND PURPOSE

The Woven EndoBridge has proved to be a safe and effective treatment, especially for wide-neck intracranial aneurysms. The recent fifth-generation Woven EndoBridge came with smaller devices. The purpose of this study was to assess the safety and efficiency of Woven EndoBridge treatment of small and very small aneurysms.

MATERIALS AND METHODS

Between September 2017 and March 2020, all consecutive patients treated with a 3- or 3.5 mm-width Woven EndoBridge device were included in this retrospective intention-to-treat study. Clinical and radiologic findings were evaluated at immediate and last-available follow-up. Angiographic outcome was assessed by an external expert reader.

RESULTS

One hundred twenty-eight aneurysms were treated with a fifth-generation Woven EndoBridge device including 29 with a width of ≤3.5 mm. Ten aneurysms were ruptured (34%). In 3 cases (10%), Woven EndoBridge treatment could not be performed because the aneurysm was still too small for the smallest available Woven EndoBridge device and another endovascular strategy was chosen. The median follow-up time was 11.2 months. Complete and adequate occlusion was obtained in 71% and 90% of the treated aneurysms, respectively. Retreatment was needed in 2 cases (10%). Symptomatic ischemic complications leading to transient neurologic deficits occurred in 2 cases (7%) (1 procedure-related and 1 device-related) but with full spontaneous recovery at discharge.

CONCLUSIONS

The fifth-generation Woven EndoBridge device seems to be a safe and technically feasible treatment for both ruptured and unruptured small and very small intracranial aneurysms, with satisfactory occlusion rates on midterm follow-up. However, further study is needed to evaluate longer-term efficiency.

Widening the Indications for Intrasaccular Flow Disruption: WEB 17 in the Treatment of Aneurysm Locations Different from Those in the Good Clinical Practice Trials

BACKGROUND AND PURPOSE

The safety and efficacy of the Woven EndoBridge (WEB) device has been shown in multiple good clinical practice trials, whereas aneurysm locations in these trials were restricted to bifurcation aneurysms located at the circle of Willis (MCA bifurcation, ICA bifurcation, anterior communicating artery, basilar artery tip). Our aim was to evaluate angiographic and clinical results with the WEB 17 in aneurysm locations that were excluded from the good clinical practice trials, assuming that the angiographic and clinical results are similar to those of the good clinical practice trials for aneurysms in traditional locations.

MATERIALS AND METHODS

We performed retrospective analysis of immediate and follow-up results of aneurysms in locations outside the good clinical practice trials in which the WEB 17 was used on an intention-to-treat approach.

RESULTS

Between June 2017 and May 2020, forty-seven aneurysms in 44 patients met the inclusion criteria. Aneurysm locations were the ICA posterior communicating artery in 19 (40.3%), the ICA paraophthalmic or choroidal locations in 4 (8.6%), anterior cerebral artery A2 segment in 13 (27.7%), MCA M1 segment in 2 (4.3%), posterior cerebral artery P2 segment in 2 (4.3%), PICA in 3 (6.4%), and the superior cerebellar artery in 4 (8.4%) cases. The procedure-related morbidity and mortality rates in the entire series were 0.0%. The early and late (<12 and >12 months) complete occlusion rates were 63.9% (23/36) and 77.8% (14/18), respectively.

CONCLUSIONS

The WEB 17 is safe and effective in aneurysm locations different from the traditional bifurcation aneurysms included in the good clinical practice trials. Further studies will help to define the entire spectrum of aneurysm morphologies and locations suitable for the WEB 17.

Treatment of Ruptured and Unruptured Intracranial Aneurysms with WEB 17 Versus WEB 21 Systems : Comparison of Indications and Early Angiographic Outcomes

BACKGROUND

The concept of intrasaccular flow diversion using the Woven EndoBridge (WEB) device changed the traditional endovascular concept for wide-necked bifurcation aneurysms. The latest technical advancement resulted in the WEB 17 system, a softer device composed of fewer wires which enables treatment of smaller more distally located aneurysms by using smaller microcatheters as compared to the WEB 21 system.

OBJECTIVE

This retrospective observational study aimed to evaluate and compare the angiographic and clinical results achieved with WEB 21 and WEB 17 in aneurysm morphologies eligible for both systems (maximum width 3-6 mm).

METHODS

Between August 2014 and August 2019 a total of 63 and 130 aneurysms with a maximum width of 3-6 mm were treated with either WEB 21 and WEB 17, respectively, at 2 neurovascular centers. Cases were analyzed based on a comparison regarding aneurysm size, location and rupture status.

RESULTS

The technical success, the periprocedural complication rate and the rate of additional devices used showed no relevant differences between the two groups. Aneurysms treated with the WEB 17 system were smaller and more frequently distally located. The overall complete occlusion rate at 3 months was higher in the WEB 17 group (65.5% versus 55.1%). The superiority of complete aneurysm occlusion achieved with WEB 17 was statistically significant in the subgroup of unruptured middle cerebral artery aneurysms.

CONCLUSION

The use of WEB 17 expands the treatment indications for intrasaccular flow-diversion towards smaller and more distally located aneurysms with a safety profile comparable with that of the WEB 21.

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

Flow diverters and flow disruption technology, alongside nuanced endovascular techniques, have ushered in a new era of treating cerebral aneurysms. Here, we provide an overview of the latest flow modulation devices and highlight their clinical applications and outcomes.

A systematic review and meta-analysis of Woven EndoBridge single layer for treatment of intracranial aneurysms

BACKGROUND AND PURPOSE

The Woven EndoBridge is an intrasaccular device for the treatment of intracranial aneurysms. The first generation consisted of a high-profile double-layer braid. This review aims to evaluate the outcomes of the new generation low-profile Woven EndoBridge single layer device for intracranial aneurysm treatment.

METHODS

A systematic review was conducted with Medline, Embase, and Web of Science Conference Proceedings databases. The search strategy provided 589 articles, 15 articles were included.

RESULTS

Fifteen articles were identified reporting the use of Woven EndoBridge single-layer devices in 963 aneurysms, mostly wide-necked bifurcation aneurysms. Procedural aneurysm rupture was reported in 8 of 963 patients (0.83%; 95%CI 0.39-1.66%) and thromboembolic events in 54 of 963 patients (5.61%, 95CI 4.31-7.26%). Cumulative morbidity was 2.85% (27/949, 95%CI 1.95-4.12%) and mortality 0.93% (9/963, 95%CI 0.46-1.80%). The overall rate of adequate aneurysm occlusion at last follow-up was 83.3% (613/736; 95%CI 80.4-85.8%). Retreatment was reported in 38 aneurysms in eight studies with 450 aneurysms with follow-up (38/450; 8.4%, 95CI 6.2-11.4%). In 12 studies comprising 644 aneurysms with follow-up, rebleeds occurred in three patients in three studies with mean follow-up between 3.3 and 14.4 months (0.47%, 95%CI 0.09-1.43%).

CONCLUSION

Woven EndoBridge single-layer is a promising new low-profile device especially for wide-neck bifurcation aneurysms, both ruptured and unruptured. No antiplatelet medication is needed which is a great advantage, especially in ruptured aneurysms. Efficacy and safety compare favorably with (stent-assisted) coiling. However, no direct comparison with other treatments is available as yet.