WEB embolization versus stent-assisted coiling: comparison of complication rates and angiographic outcomes

Variability patterns in dual antiplatelet therapy following endovascular repair of intracranial aneurysms: Insight into regimen heterogeneity and the need for a consensus

This comprehensive review delves into the evolving field of neurointervention for intracranial aneurysms, exploring the critical adjunct of Dual Antiplatelet Therapy (DAPT) to endovascular coiling, stent-assisted coiling (SAC), flow-diversion stents, and flow-disruption (intrasaccular) devices. Despite growing evidence supporting the success of DAPT in reducing thromboembolic events, the lack of consensus on optimal regimens, doses, and duration is evident. Factors contributing to this variability include genetic polymorphisms affecting treatment response and ongoing debates regarding the clinical significance of hemorrhagic complications associated with DAPT. This review analyzes pre- and post-procedural antiplatelet usage across various interventions. The imperative lies in ongoing research to define optimal DAPT durations, ensuring a nuanced approach to the delicate balance between thrombosis and hemorrhage in intracranial aneurysm management.

The Clinical and Radiological Outcomes of the Multimodal Use of the Woven EndoBridge Device: A Large Multicenter Study

BACKGROUND

The Woven EndoBridge (WEB) is a device used for intrasaccular flow diversion, designed for the elimination of wide-necked bifurcation aneurysms from the circulation. In this study, we aim to assess the safety and efficacy of the WEB and its uses in treating aneurysms of different morphologies and locations.

METHODS

In a retrospective analysis, we compiled a comprehensive dataset from patients treated with the WEB device across three major Australian neurovascular centers from May 2017 to September 2023. The case series encompassed a spectrum of aneurysm types, including wide-necked bifurcation, sidewall, and irregularly shaped aneurysms, as well as cases previously managed with alternative therapeutic strategies. This study additionally encompasses cases where aneurysms were managed using the WEB device in combination with supplementary endovascular devices.

RESULTS

The study included 169 aneurysms in 161 patients. The rate of satisfactory aneurysm occlusion was 85.6%, with 86.7% of patients maintaining good functional status at their most recent follow-up. The procedure exhibited a low mortality rate of 0.6% and a thromboembolic complication rate of 7.1% (n = 12/161). There were no instances of postoperative re-rupture and the procedure-related hemorrhage rate was low (1.2%, n = 2/169), aligning with the literature regarding the safety and efficacy of the WEB device.

CONCLUSIONS

Our multicenter trial reinforces the WEB device's role as an effective and safe modality for intracranial aneurysm management, supporting its expanded application beyond wide-necked bifurcation aneurysms. Further prospective studies are required to delineate its evolving role fully.

Large Single-Center Experience with Short-Term Follow-up of Neqstent-Assisted Coiling

BACKGROUND AND PURPOSE

Endovascular treatment of wide-neck bifurcation aneurysms has historically proved difficult with variable outcomes. Different endovascular techniques such as balloon-assisted coiling, stent-assisted coiling, or intrasaccular devices provide a varied range of efficacy and safety. Neqstent-assisted coiling is a new device and technique that aim to provide a maximum of both. We analyzed the early clinical and radiologic outcomes after the use of this new technique and device in our practice.

MATERIALS AND METHODS

This study was a retrospective analysis of ruptured and unruptured intracranial aneurysms treated with the Neqstent. The primary radiologic outcomes were quantified on DSA, CTA, or MRA using the modified Raymond-Roy criteria. The outcomes were defined as immediate complete occlusion (modified Raymond-Roy criteria 1) and complete (modified Raymond-Roy criteria 1) and adequate occlusion (modified Raymond-Roy criteria 1 and modified Raymond-Roy criteria 2) at 6 months posttreatment. The primary safety outcome was the rate of device-related adverse events. Secondary safety outcomes included time to discharge and change in the mRS score at 6-month follow-up.

RESULTS

Twenty patients were treated with the Neqstent from November 2020 to January 2023. Nine had unruptured aneurysms, and 11 were patients with subarachnoid haemorrhage due to ruptured aneurysms. Eighteen of 20 aneurysms (90%) treated demonstrated complete occlusion (modified Raymond-Roy criteria 1) on immediate postembolization angiograms. Sixteen of 17 aneurysms treated (94.1%) remained adequately occluded on 6-month follow-up (modified Raymond-Roy criteria 1 and modified Raymond-Roy criteria 2). Immediate postoperative complications occurred in 2 patients; only 1 patient had residual neurologic deficits at 6 months (mRS = 2).

CONCLUSIONS

Management of large, wide-neck aneurysms remains difficult, with high rates of recurrence and complications. The use of the Neqstent shows promising short-term results for the treatment of complex wide-neck aneurysms. Initial complication rates for our cohort were relatively high. However, this result is likely related to the initial learning experience of device deployment and the use of antiplatelets.

Rescue Stenting for Inadvertent Branch Vessel Occlusion Following Cerebral Aneurysm Embolization With the Woven EndoBridge Device

Intrasaccular flow modification with devices like the Woven EndoBridge (WEB, MicroVention, Inc., Aliso Viejo, California, US) is an increasingly utilized endovascular treatment for bifurcation aneurysms. Among the potential complications of the procedure is branch vessel occlusion. There are no previous publications of rescue stenting for inadvertent branch vessel occlusion with the WEB device. We report two cases of rescue stenting following branch vessel occlusion after cerebral aneurysm embolization with the WEB device. In both cases, rescue stenting with a Neuroform Atlas stent Stryker, Fremont, CA, US) successfully revascularized the occluded vessel and led to good patient outcomes.

Initial Experiences with the Trenza Embolization Device for the Treatment of Wide-Neck Intracranial Aneurysms: A 12-Patient Case Series

The Trenza embolization device is a frame coil implant with flow-disruption properties and is a new alternative to treat challenging mid-to-large-sized broad-neck bifurcation or sidewall aneurysms. We conducted an observational single-center retrospective study of 12 consecutive patients treated for 10 unruptured and 2 ruptured 6- to 12-mm broad-neck bifurcation or sidewall aneurysms with the Trenza device during 2022-2023. The median patient age was 64 years (interquartile range, 59-70 years), 58% were women, the median largest aneurysm diameter was 9.6 mm (interquartile range, 7.5-11.9 mm), the median dome-to-neck ratio was 1.8 (interquartile range, 1.6-1.9), the most common aneurysm locations were the anterior communicating artery (33%) and basilar artery tip (33%). After a median follow-up of 6.5 months, adequate aneurysm occlusion was achieved in 83%. There were 3 major ischemic complications (25%), leading to 2 permanent neurologic deficits (17%) and 1 transient neurologic deficit (8%). There was 1 fatal rupture of a treated aneurysm 1.6 months after the index treatment. Two patients were retreated (17%). Ischemic complications occurred in patients after a too-dense coil packing at the base of the aneurysm. No technical issues related to the device were encountered. In summary, an adequate aneurysm occlusion rate was achieved using the Trenza-assisted coiling technique for otherwise challenging mid-to-large-sized broad-neck aneurysms. Ischemic complications seemed to occur following overdense coiling at the base of the aneurysm.

WEB embolization of very broad-based intracranial aneurysms with a dome-to-neck ratio ≤ 1.1

OBJECTIVE

The Woven EndoBridge (WEB) is a well-studied intrasaccular device for endovascular treatment of wide-necked bifurcation aneurysms. We evaluated the feasibility, safety and efficacy of the WEB for the treatment of very broad-based aneurysms with a dome-to-neck ratio ≤ 1.1.

METHODS

Thirty-four aneurysms treated at three neurovascular centers were retrospectively identified. The mean aneurysm size was 5.5 ± 1.6 mm with a mean neck width of 4.7 ± 1.5 and a mean dome-to-neck ratio of 1.0 ± 0.1. The primary outcome measures were immediate technical treatment success by WEB only, complete or near-complete occlusion at 6-month follow-up and ischemic stroke.

RESULTS

Aneurysm embolization by WEB only was technically feasible in 79.4%. Additional stenting was required in 14.7%. In two aneurysms (5.9%), WEB implantation failed, and the aneurysm was treated by stent- and balloon-assisted coiling, respectively. Thromboembolic events occurred during 5 interventions (14.7%), all of these performed in ruptured aneurysms. One patient (2.9%) remained asymptomatic (follow-up modified Rankin scale [mRS] score: 0), 2 patients (5.9%) had a transient deficit (mRS 0 and 1, respectively), and 2 (5.9%) had a disabling ischemic stroke (mRS 3, respectively). Mid-term angiographic follow-up of 29 patients (4.0 ± 2.6 months, range: 2-9 months) showed complete occlusion (WEB occlusion scale [WOS] A) in 41.4%, near-complete occlusion (WOS B) in 34.5%, a neck remnant (WOS C) in 10.3%, and aneurysm remnants (WOS D) in 13.8%.

CONCLUSIONS

WEB embolization of very broad-necked aneurysms was technically feasible and could be achieved by WEB only in the majority of cases. Considering the challenging anatomy of very broad-based aneurysms, the WEB procedure was reasonably safe and efficient.

Woven EndoBridge versus stent-assisted coil embolization for the treatment of ruptured wide-necked aneurysms: A multicentric experience

BACKGROUND

The potentially higher risk of hemorrhagic complications is of concern in stent-assisted coiling (SAC) of ruptured wide-necked intracranial aneurysms (IAs). The Woven EndoBridge (WEB) is considered an appealing alternative since antiplatelet therapy is not required. Herein, we aimed to compare the safety and effectiveness of WEB vs. SAC for the treatment of ruptured wide-necked IAs.

METHODS

This was an international cross-sectional study of consecutive patients treated for ruptured wide-neck IAs with WEB or SAC at four high-volume neurovascular centers between 2019 and 2022. Primary and secondary efficacy outcomes were radiographic aneurysm occlusion at follow-up and functional status at last follow-up. Safety outcomes included periprocedural hemorrhagic/ischemia-related complications.

RESULTS

One hundred five patients treated with WEB and 112 patients treated with SAC were included. The median procedure duration of endovascular treatment was shorter for WEB than for SAC (69 vs. 76 min; p = 0.04). There were no significant differences in complete aneurysm occlusion rates (SAC: 64.5% vs. WEB: 60.9%; adjusted OR [aOR] = 0.70; 95%CI 0.34-1.43; p = 0.328). SAC had a significantly higher risk of complications (23.2% vs. 9.5%, p = 0.009), ischemic events (17% vs. 6.7%, p = 0.024), and EVD hemorrhage (16% vs. 0%, p = 0.008). The probability of procedure-related complications across procedure time was significantly lower with WEB compared with SAC (aOR = 0.40; 95%CI 0.20-1.13; p = 0.03).

CONCLUSION

WEB and SAC demonstrated similar obliteration rates at follow-up when used for embolization of ruptured wide-necked IAs. However, SAC showed higher rates of procedure-related complications primarily driven by ischemic events and higher rates of EVD hemorrhage. The overall treatment duration was shorter for WEB than for SAC.

Oversizing of the Woven EndoBridge for Treatment of Intracranial Aneurysms Improves Angiographic Results (WEBINAR)

OBJECTIVE

Several studies have demonstrated a high safety and efficacy profile of the Woven EndoBridge (WEB) for endovascular aneurysm treatment. However, contemporary large-scale studies of the WEB are rare. This multicenter study attempts to set a benchmark for state-of-the-art WEB treatment with consistent application of the WEB oversizing technique.

METHODS

This is a retrospective, multicenter study of aneurysms (dome width 2-10 mm) treated with the WEB between 2015 and 2023. Patient and aneurysm characteristics, complications, and clinical and angiographic outcomes were analyzed.

RESULTS

The study consisted of 247 patients treated for 251 aneurysms (25.5% ruptured, 5.6% recurrent). WEB implantation was feasible in 98.8%, achieving a mean WEB/dome ratio of 1.2 ± 0.1. The thromboembolic complication rate was 7.2%, which was higher in ruptured versus unruptured aneurysms (hazard ratio: 2.8, 95%CI: 1.0-7.6, P = 0.04), but lower in cases where WEB 17 was used (hazard ratio: 4.0, 95%CI: 1.4-11.2, P = 0.01). Neurological complications occurred in 8 procedures (3.2%), including 3 (1.2%) major, and 5 (2.0%) minor events. Procedural morbidity and mortality were 0.8% and 0%, respectively. Mid-term complete and adequate occlusion rates were 66.3% and 88.4%, respectively. The retreatment rate was 5.2%. Feasibility, complication, and occlusion rates were comparable between typical and atypical aneurysm locations.

CONCLUSIONS

Oversizing the WEB and using currently available WEB types in this series resulted in slightly better treatment outcomes compared to early WEB studies, confirming the high safety, feasibility, and efficacy of this technique.

The Enterprise stent…still useful after all these years

BACKGROUND

The Enterprise stent (Codman Neuro, Massachusetts, USA) received Food and Drug Administration (FDA) approval in 2007 for stent-assisted coiling (SAC). Since its introduction, newer stents and devices for aneurysm treatment have been developed resulting in a shift in the utilization of this stent from SAC to other off-label indications.

OBJECTIVE

To describe our experience with the Enterprise stent being used for SAC and other off-label indications.

METHODS

This is a multi-center retrospective review of the use of the Enterprise stent between 2018 and 2023. All patients in which the Enterprise stent was successfully deployed were included in the study.

RESULTS

Our study cohort comprised of 194 patients, mostly females (n = 112, 57.7%), with a mean age of 63.2 years ± 14.3. The Enterprise stent was used for SAC in only 24 (12.4%) patients and was used for rescue stenting in stroke in 101 patients (52.1%), treatment of intracranial stenosis in 53 patients (27.3%), treatment of in-stent stenosis in 1 patient (0.5%), and for treatment of dissections in 15 patients (7.7%). From 2018 to 2023, the use of Enterprise stents for SAC significantly decreased (p < 0.0001) while the use of Enterprise stents for non-SAC purposes was insignificantly variable (p = 0.05).

CONCLUSION

Our study shows that the Enterprise stent remains a reliable tool in neuroendovascular procedures, even if its original intended use has been supplanted by other devices.

Woven EndoBridge Device for Unruptured Wide-Neck Bifurcation Aneurysm: A Multicenter 5-Year Follow-up

BACKGROUND AND OBJECTIVES

This multicenter study aimed to assess the safety and efficacy of the Woven EndoBridge (WEB) device for treating unruptured wide-neck intracranial bifurcation aneurysms (WIBAs) with short-, mid-, and long-term follow-ups (FUPs).

METHODS

Consecutive patients with unruptured WIBAs treated with WEB between December 2014 and January 2018 were included. Patient, aneurysm, and device characteristics were collected and analyzed retrospectively. Morbidity and mortality rates were determined by collecting intraprocedural, periprocedural, and delayed complications. Aneurysm occlusion was assessed at 1, 3, and 5 years using a 3-grade scale: complete occlusion, neck remnant, and residual aneurysm. Complete occlusion and neck remnant were considered as adequate occlusion. Patients who received re-treatment were also evaluated.

RESULTS

The study included 104 consecutive patients (55.8% female, mean age 58.6 ± 11.8 years). Aneurysm maximum size, neck, and dome-to-neck mean were, respectively, 6.9 ± 2.1 mm, 4.5 ± 1.2 mm, and 1.4 ± 0.3 mm. One-year FUP was collected for 95 patients, and 3- and 5-year FUPs were collected for 83 patients. Adequate occlusion was observed at 1-year FUP in 90.5% (86/95), 91.6% (76/83) was observed at 3-year FUP, and 92.8% (77/83) at 5-year FUP. None of the aneurysms bled after treatment. During FUP, 6/83 patients (7.2%) were re-treated for residual aneurysm. Morbidity and mortality rates closely related to aneurysm occlusion were 0% (0/104).

CONCLUSION

The WEB device was safe and effective for treating unruptured WIBAs, both in short-term and long-term FUPs.

Identifying risk factors for perioperative thromboembolic complications in patients treated with the Woven EndoBridge device

INTRODUCTION

Woven EndoBridge (WEB) is a new endovascular treatment option for wide necked bifurcation aneurysms. Results from the WEB-IT trial showed a 0% risk of thromboembolic complications within 30 days post-op but the rate reported in the literature is as high as 10%. We are exploring potential risk factors associated with immediate thromboembolic complications in patients treated with the WEB device.

METHODS

Retrospective study of forty-two patients with intracranial aneurysms who were treated with WEB at a single center from 2019-2021. Data was collected on patient demographics, comorbidities, aneurysm characteristics, procedural details, and hospital course. Bivariate analyses were performed to compare patients who experienced a periprocedural ischemic stroke to those who did not. Multiple logistic regression modeling was performed to identify independent risk factors for thromboembolic complications.

RESULTS

Of the 42 patients that were treated with WEB, 6 suffered an ischemic stroke (AIS). These patients were more likely to have an underlying diagnosis of arrythmias (p value = 0.007). Furthermore, they had a median angle of 32.0° in the true neck view on diagnostic angiogram compared to 19.5° (p value = 0.046). Lastly, they had a longer procedure length of 228 min compared to 178 min (p value = 0.002). Patients with thromboembolic complications had a longer length of stay in the hospital and worse outcomes at three months follow up. On logistic regression modeling, these risk factors did not reach statistical significance.

CONCLUSION

Risk factors of thromboembolic complications after WEB placement include cardiac arrythmias, acute aneurysmal angle in the true neck view and a longer procedure length.

Comparative effectiveness of stent-assisted coiling and Woven EndoBridge embolization for the treatment of unruptured wide-neck bifurcation intracranial aneurysms

OBJECTIVE

Woven EndoBridge (WEB) intrasaccular flow disruptors and stent-assisted coiling (SAC) are viable endovascular treatment options for wide-neck bifurcation intracranial aneurysms (WNBAs). Data directly comparing these two treatment options are limited. The authors aimed to compare radiographic occlusion rates and complication profiles between patients who received WEB and those who received SAC for WNBAs.

METHODS

Retrospective review of a prospectively maintained cerebrovascular procedural database was performed at a single academic medical center between 2017 and 2021. Patients were included if they underwent WEB embolization or SAC of an unruptured WNBA. SAC patients were propensity matched to WEB-embolized patients on the basis of aneurysm morphology. Complete and adequate (complete occlusion or residual neck remnant) occlusion rates at last angiographic follow-up, as well as periprocedural complications, were compared between the two groups. A cost comparison was performed for a typical 5-mm WNBA treated with WEB versus SAC by using manufacturer-suggested retail prices.

RESULTS

Thirty-five WEB and 70 SAC patients were included. Aneurysm width, neck size, and dome-to-neck ratio were comparable between groups. Follow-up duration was significantly longer in the SAC group (median [interquartile range] 545 [202-834] days vs 228 [177-494] days, p < 0.001, Mann-Whitney U-test). Complete (66% of WEB patients vs 69% of SAC patients) and adequate (94% WEB vs 91% SAC) occlusion rates were similar between groups at the last available angiographic follow-up (p = 0.744, chi-square test). Complete occlusion rates were comparable on Cox regression analysis after correction for follow-up duration (hazard ratio 1.5, 95% CI 0.8-3.1). Average time to residual aneurysm or neck formation was not statistically different between treatment groups (613 days for SAC patients vs 347 days for WEB patients, p = 0.225, log-rank test). Periprocedural complications trended higher in the SAC group (0% WEB vs 9% SAC, p = 0.175, Fisher exact test), although this finding was not significant. The equipment costs for a typical SAC case were estimated at $18,950, whereas the costs for a typical WEB device case were estimated at $18,630.

CONCLUSIONS

Midterm complete and adequate occlusion rates were similar between patients treated with WEB and those treated with SAC. Given these comparable outcomes, there may be equipoise in treatment options for WNBAs.

Comparative assessment of woven endobridge embolization and standard coil occlusion for the treatment of ruptured basilar tip aneurysms

PURPOSE

Endovascular coil occlusion represents the standard treatment for basilar tip aneurysms. Recently, this role has been rivalled by intrasaccular flow disruptors across numerous centres. We retrospectively compared WEB embolization and coiling for the treatment of ruptured basilar tip aneurysms.

METHODS

Patients treated with WEB or coiling at four neurovascular centres were reviewed. Procedure-related complications, clinical outcome, and angiographic results were retrospectively compared.

RESULTS

The study included 23 patients treated with the WEB (aneurysm size: 6.6 ± 1.9 mm) and 56 by coiling (aneurysm size: 6.7 ± 2.5 mm). Stent-assistance was more often necessary with coiling than with WEB embolization (32% vs. 4%, p = 0.009). A modified Rankin scale score ≤ 2 at discharge had 21 (37.5%) patients in the coiling group and 12 (52.2%) in the WEB group (p = 0.235). Immediate complete and adequate occlusion rates were 52% for the WEB and 87% for coiling. At short-term follow-up, these rates were 87% for the WEB and 72% for coiling, respectively. There was no delayed aneurysm re-bleeding during follow-up.

CONCLUSION

Both coiling and WEB seem to prevent rebleeding in ruptured BTA aneurysms. WEB embolization required less frequently stent-support than coiling, potentially advantageous for SAH patients to avoid anti-platelet therapy in the light of concomitant procedures like ventricular drainage.

Republished:Delayed aneurysm rupture following treatment with the WEB embolization device

Delayed rupture of an aneurysm following WEB embolization has not yet been reported. We present a case of a multiply ruptured anterior communicating artery aneurysm treated via WEB embolization. A post-treatment CT scan confirmed no evidence of rebleeding during treatment. Four hours after treatment, the patient developed an acute, significant increase in intracranial pressure with bloody ventriculostomy output, with CT scan demonstrating new parenchymal and intraventricular hemorrhage. The aneurysm was subsequently treated via microsurgical clipping that did not identify an "uncovered" bleb or rupture source.

Intrasaccular flow disruption for brain aneurysms: a systematic review of long-term outcomes

OBJECTIVE

The long-term safety and efficacy of intrasaccular flow disruption (IFD) for the treatment of brain aneurysms remain unclear. With accumulating experience and increasing use of IFD devices, recent studies have provided additional data regarding their outcomes. This review summarizes the long-term outcomes of IFD-treated brain aneurysms.

METHODS

A systematic literature review was performed on May 23, 2021, in PubMed, Web of Science, and Ovid MEDLINE for aneurysm treatment outcomes with IFD devices. Procedural details, including use of adjunctive devices and complications, were collected. The quality of studies was assessed using the Downs and Black checklist. Angiographic outcomes were classified as complete occlusion, residual neck, and residual aneurysm. Other outcomes included need for retreatment, permanent neurological deficit, and mortality. Pooled analyses were performed.

RESULTS

The final analysis comprised 1217 patients with 1249 aneurysms from 22 studies. The mean aneurysm diameter and neck width were 6.9 and 4.5 mm, respectively, and 27.6% of aneurysms were ruptured. The complete occlusion rates at 12 months and final follow-up (pooled mean duration 15.7 months) were 50.1% and 58.2%, respectively. Adjunctive devices were used in 6.4% of cases. The rates of hemorrhage, symptomatic infarction, permanent neurological deficit, and mortality were 1.2%, 2.8%, 1.0%, and 2.6%, respectively.

CONCLUSIONS

IFD is a very safe treatment for appropriately selected brain aneurysms with low complication and neurological deterioration rates. However, complete occlusion is achieved in only half of IFD-treated aneurysms at 1 year with a modest increase beyond this time point. As the majority of the studies were single arm, the pooled data are subject to selection and reporting biases. Future device developments, increased operator experience, and direct comparisons with alternative endovascular strategies and surgical clipping may clarify the role of IFD in aneurysm management.

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%.

Comparison of angiographic outcomes and complication rates of WEB embolization and coiling for treatment of unruptured basilar tip aneurysms

Endovascular coiling represents the standard treatment for basilar tip aneurysms. Some of these aneurysms are not amenable to conventional coiling due to a complex aneurysm geometry, hence, novel devices such as the Woven Endobridge (WEB) have been developed. We retrospectively compared WEB embolization and coiling for the treatment of unruptured basilar tip aneurysms. Patients treated with WEB or coiling at four centers were reviewed. Procedure-related complications, clinical outcome and angiographic results were retrospectively evaluated and compared. Forty patients treated with the WEB and 35 patients treated by coiling were included. Stent-assistance was more often necessary for coiling than for WEB embolization (71% vs 2.5%, p < 0.001). The technical success rates were 100% for both methods. The overall complication rates were not significantly different between groups (WEB: 5%, coil: 11%, p = 0.409). Procedural morbidity rates were 9% in the coiling group and 2.5% in the WEB group (p = 0.334). There was no mortality. Treatment duration was shorter for WEB implantation than for coiling (p = 0.048). At mid-term follow-up, complete occlusion, neck remnants and aneurysm remnants were observed in 89%, 4% and 7% for the WEB, respectively, and in 100%, 0% and 0% for coiling. While complication rates and mid-term angiographic outcome was comparable between the groups, the WEB was associated with a shorter treatment duration and required stent-assistance less frequently. The choice of the treatment modality should be made based on the specific aneurysm characteristics, the individual experience of the neurointerventionalist and patient preference.

Woven EndoBridge versus stent-assisted coil embolization of cerebral bifurcation aneurysms

OBJECTIVE

Stent-assisted coil (SAC) embolization has been the mainstay endovascular treatment for bifurcation aneurysms. The recent introduction of the Woven EndoBridge (WEB) device has presented an alternative endovascular treatment modality for these aneurysms. Direct comparisons of outcomes between these two modalities are limited in the literature. Here, the authors compared the outcomes of bifurcation aneurysms treated with SAC and WEB devices.

METHODS

This retrospective single-center study comprised 148 bifurcation aneurysms that were treated endovascularly with SAC or WEB devices between 2011 and 2019. The primary outcome was complete occlusion of the aneurysm at 6 months on catheter angiography.

RESULTS

The SAC and WEB cohorts comprised 85 and 63 aneurysms, respectively. The baseline characteristics were well balanced after inverse probability weight (IPW) adjustment, except for smoking status. The 6-month complete occlusion rate was higher in the WEB cohort than the SAC cohort (67.4% vs 40.6%; unadjusted OR [95% CI] 3.014 [1.385-6.563], p = 0.005). However, this difference in complete occlusion rates did not remain significant after IPW adjustment and multiple imputations. The neck remnant rate was lower in the WEB cohort than the SAC cohort (20% vs 50%; OR [95% CI] 0.250 [0.107-0.584], p = 0.001), and this difference remained significant after IPW adjustment (OR [95% CI] 0.304 [0.116-0.795], p = 0.015) and multiple imputations.

CONCLUSIONS

Use of SAC and WEB demonstrated comparable 6-month complete occlusion rates for bifurcation aneurysms. WEB appeared to be associated with a lower rate of neck remnant at 6 and 12 months compared with SAC. WEB was also associated with fewer complications and decreased retreatment rates compared with SAC.

WEB vs coiling in ruptured aneurysms: A propensity score matched comparison of safety and efficacy

BACKGROUND

We aim to compare the safety and efficacy of WEB with coiling for acutely ruptured aneurysms.METHODS: All consecutive ruptured aneurysms with width suitable for WEB (2-10 mm) treated over 5 years (1/1/2015 to 31/12/2019) were included. We recorded WFNS, Fisher grade, patient demographics and aneurysm characteristics (size, location, D/W and aspect ratio, lobulation). Primary endpoints were mRS status at 3 months, aneurysm occlusion on latest available imaging follow-up, retreatment rate and procedural complications. We applied propensity score matching using aneurysm morphology (size, D/N ratio, ASPECT ratio and lobulation) to optimise matching for WEB versus coil comparison and minimise the effects of confounding.

RESULT

A total of 493 patients were identified, 97 treated with the WEB device. 1:1 propensity score matching was used to establish a matched group of 97 patients treated with coiling. The WEB arm showed 3% procedural complication rate, with no haemorrhagic complications and use of adjunctive device in 4%. Satisfactory occlusion on follow-up (mean 14 months) was 79%, with 19% retreatment rate. The coil arm had 8% complication rate, with use of an adjunctive device in 52% of cases (balloon 44%, stent 8%). Satisfactory occlusion on follow-up (mean 22 months) was 90%, with 8% retreatment rate.

CONCLUSION

Treatment of ruptured wide-necked bifurcation aneurysms with WEB has a lower complication rate than coiling with high rate of satisfactory occlusion. However, there was a higher retreatment rate when compared with patients treated with coiling. An adjunct device (balloon or stent), was used in over 50% of aneurysms in the coiling group.

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.

Comprehensive review of the recent advances in devices for endovascular treatment of complex brain aneurysms

The International Subarachnoid Aneurysm Trial (ISAT) showed superiority for endovascular treatment of ruptured aneurysms and technology has since moved on rapidly. Many approaches and technology now exist for the endovascular management of ruptured and unruptured intracranial aneurysms, which reflects their varied nature - there is no one-size-fits-all technique. We aim to provide an overview of the various classes of device and the major developments over the past decade. Coiling is the oldest of the technology and continues to demonstrate high levels of occlusion and acceptable risks, making it the default treatment choice, particularly in the acutely ruptured aneurysm setting. Advances on coiling include the use of adjuncts such as balloons, stents and fully retrievable temporary neck-bridging devices, which have facilitated the treatment of more complex aneurysms. Flow divertors have also revolutionised complex aneurysm treatment with small added risk in acute aneurysm treatment and seek to remodel the aneurysm-vessel interface without accessing the aneurysm sac. The latest development and most promising avenue appears to be intrasaccular flow disrupting devices like WEB, Contour and Neqstent that provide excellent opportunities to treat wide neck complex aneurysm with minimal mortality and morbidity and good occlusion rates and may in future replace a significant number of stent-assisted coiling too.

Clinical audit comparing radiation dose metrics between WEB and coil embolisation in the treatment of intracranial aneurysms

INTRODUCTION

Intrasaccular flow disruption is a new and effective endovascular treatment for intracranial aneurysms. While endovascular treatment is a minimally invasive procedure, it does carry a radiation risk. As radiation dose should be kept as low as reasonably achievable (ALARA), the main objective of this study was to analyse KAP (kerma area product), fluoroscopy and procedure time during the treatment of aneurysms treated with coiling and the Woven-EndoBridge (WEB) device. A secondary objective was to look at the reference air kerma (RAK) to determine if the patient receives a dose that could cause tissue effects.

METHODS

KAP, fluoroscopy and procedure time were retrospectively analysed in patients who had an aneurysm treatment. Aneurysms with diameters of 4-11mm, over a four-year period, in the anterior and posterior circulation of the brain were analysed in this study. Patients were treated by coiling or WEB. RAK were summed together in the working projection to give an estimated entrance surface dose (ESD) in cases with the highest KAP.

RESULTS

A total of 47 aneurysms treated with WEB and 104 aneurysms treated with coiling techniques met the inclusion criteria. The average KAP was 6884.1 ± 2774.4μGym² with coiling techniques and 5658.7 ± 1602.5μGym² with WEB (p=0.006; CI =363-2086μGym²). This demonstrates an 18% reduction with WEB. Mean fluoroscopy time for coiling was 63.5 ± 42.6minutes and 33.8 ± 28.8minutes for WEB (p=<0.001; CI=16-43minutes). Fluoroscopy time was reduced by nearly 50% with WEB. On average, there was a 27-minute reduction of procedure time when using WEB compared to coiling. The RAK determined for the working projections did not exceed the 2Gy threshold for tissue effects.

CONCLUSION

Treatment of aneurysms using the WEB shows a reduction in KAP, fluoroscopy, and procedure time. This study further demonstrates the benefits of intrasaccular flow disruption for treatment of intracranial aneurysms.

Adjustment of Malpositioned Woven EndoBridge Device Using Gooseneck Snare: Complication Management Technique

The Woven EndoBridge (WEB) is an intrasaccular flow-disrupting device for the treatment of wide-necked saccular cerebral aneurysms. As with any neuroendovascular device, complications in the form of malpositioning and migration must be managed quickly and safely. Few studies have reported complication management techniques in instances of dislocated or migrated WEB devices. We retrospectively describe a case of a malpositioned WEB device that was successfully adjusted with the use of a gooseneck snare. Multiple other intra-procedural bailout strategies for management of WEB malposition and migration were considered, and are herein discussed. Operators should be aware of the causes of WEB malposition and a variety of bailout strategies.

Implantation of Large Diameter (5.5-6 mm) Derivo Embolization Devices for the Treatment of Cerebral Aneurysms

BACKGROUND

The efficacy of flow diverters is dependent upon robust wall apposition in the parent artery. Usage in large caliber cerebral vessels has therefore been limited as few implants with diameters > 5 mm exist. We present our initial experience in treating cerebral aneurysms using the 5.5 mm and 6 mm diameter implants of the Derivo embolization device (DED).

METHODS

Our prospectively maintained institutional database was reviewed to identify patients in whom a > 5 mm DED was implanted between November 2016 and February 2021. The primary efficacy outcome was complete or near-complete aneurysm occlusion at 6 months (O'Kelly-Marotta, OKM, C-D, adapted for magnetic resonance angiography). Safety outcomes included 30-day major morbidity defined as modified Rankin Score (mRS) 3-5, mortality, serious adverse events and procedural complications.

RESULTS

A total of 21 large diameter DEDs were deployed in 18 patients (age 59.5 ± 14.1 years), harboring 19 unruptured aneurysms. Of the aneurysms 14 (73.7%) were saccular in morphology (sac diameter 10.9 ± 5.5 mm, neck diameter 6.8 ± 3.1 mm), 3 (15.8%) aneurysms were dissecting, 1 (5.3%) iatrogenic pseudoaneurysm and 1 (5.3%) fusiform. Aneurysm locations were: ICA (internal carotid artery) (n = 17); (7 cavernous, 4 paraophthalmic, 2 paraclinoid, 1 petrous, 2 communicating, 1 cervical); vertebrobasilar (n = 2). Adjunct stenting to optimize proximal wall apposition was undertaken in 5 (27.8%) patients. At 6 months 75% of patients followed-up met the primary efficacy endpoint (OKM C-D). There were no serious adverse events, 30-day major morbidity (mRS 3-5) or mortality.

CONCLUSION

Implantation of large diameter (5.5 mm and 6 mm) DEDs into capacious cerebral vessels to treat a range of complex aneurysms is safe and technically feasible but may require adjunct stenting to optimize proximal wall apposition. Short-term efficacy of this device subset is comparable to previous DED and other flow diverter studies. Long-term follow-up and comparative studies are required for further assessment.

Ticagrelor versus Clopidogrel in the Dual Antiplatelet Regimen for Intracranial Stenting or Flow-Diverter Treatment for Unruptured Cerebral Aneurysms: A Single-Center Cohort Study

BACKGROUND AND PURPOSE

Ticagrelor is a novel P2Y12 antagonist, and little is known about its efficacy and safety in the endovascular treatment of aneurysms. This study evaluated the efficacy and safety of ticagrelor versus clopidogrel for stent-assisted coiling or flow-diversion treatment in patients with unruptured cerebral aneurysms.

MATERIALS AND METHODS

From November 2003 to February 2019, two hundred one patients (mean age, 57.5 years; 156 women) with 233 unruptured aneurysms underwent stent-assisted coiling or flow-diversion treatment. All patients received antiplatelet therapy of aspirin plus clopidogrel (clopidogrel group, 121 patients with 140 aneurysms) or aspirin plus ticagrelor (ticagrelor group, 80 patients with 93 aneurysms). The clinical and radiologic data in each group were retrospectively reviewed and compared.

RESULTS

Two hundred thirty-six procedures were performed, including stent-assisted coiling (n = 101) and flow diversion (n = 135). At 90 days, the primary outcome-a composite of any stroke and death-occurred in 9.9% of the clopidogrel group and 8.6% of the ticagrelor group (P = .822). Ischemic stroke occurred in 10 (7.0%) of the clopidogrel group and 7 (7.5%) of the ticagrelor group (P > .999). Disabling stroke occurred in 4 (2.8%) in the clopidogrel group and in 4 (4.3%) in the ticagrelor group (P = .716). Ninety-day death occurred in 3 (2.1%) in the clopidogrel group and 1 (1.1%) in the ticagrelor group (P > .999). Any bleeding at 90 days occurred in 13 (9.2%) in the clopidogrel group and 6 (6.5%) in the ticagrelor group (P = .479).

CONCLUSIONS

Ticagrelor appears to be as effective and safe as clopidogrel in stent-assisted coiling or flow-diversion treatment for unruptured cerebral aneurysms.

Safety and Efficacy of the Woven EndoBridge Device for Treatment of Ruptured Intracranial Aneurysms: A Systematic Review and Meta-analysis

BACKGROUND

The Woven EndoBridge device has been increasingly used to treat wide-neck aneurysms, particularly ruptured ones.

PURPOSE

Our aim was to investigate the safety and efficacy of the Woven EndoBridge device in the treatment of ruptured intracranial aneurysms.

DATA SOURCES

All studies evaluating the outcomes of Woven EndoBridge device use in the treatment of ruptured intracranial aneurysms from inception through 2020 were searched on Ovid Evidence-Based Medicine Reviews, EMBASE, MEDLINE, Scopus, and the Web of Science Core Collection.

STUDY SELECTION

Eighteen studies encompassing 487 patients with 496 ruptured aneurysms treated with the Woven EndoBridge device were included.

DATA ANALYSIS

We studied rates of rerupture and retreatment, angiographic outcomes at the last follow-up point, complications, and mortality rates. Data were collected on anticoagulation and antiplatelet use. Meta-analysis was performed using the random effects model.

DATA SYNTHESIS

The rate of late rebleeding was 1.1% (95% CI, 0.1%-2.1%). The treatment-related perioperative complication rate and the overall clinical complication rate were 13.2% (95% CI, 9.2%-17.2%) and 3.2% (95% CI, 1.6%-4.7%), respectively. Thirteen hemorrhagic (2%; 95% CI, 0.8%-3.3%) and 41 thromboembolic (6.8%; 95% CI, 4.6%-9%) complications occurred. Favorable clinical outcomes were achieved in 85% of patients. Procedure-related mortality and overall mortality rates were 2.1% (95% CI, 0.8%-3.3%) and 11.5% (95% CI, 7%-16%), respectively. At last follow-up, an adequate occlusion rate was 87.3% (95% CI, 82.1%-92.4%) and the retreatment rate was 5.1% (95% CI, 3%-7.3%).

LIMITATIONS

Our meta-analysis is limited by selection bias and high heterogeneity.

CONCLUSIONS

This meta-analysis demonstrated the safety and efficacy of the Woven EndoBridge device in the management of ruptured aneurysms, but further studies are needed.

Influence of operator experience on the technical and clinical results of Woven EndoBridge endovascular treatment for intracranial aneurysms

BACKGROUND & PURPOSE

The safety and efficacy of the Woven EndoBridge (WEB) device has been proven in recent multicenter trials. This study investigated whether operator experience influences WEB treatment-related outcomes.

MATERIAL AND METHODS

This was a retrospective analysis of a prospectively collected multicenter database. The data of all patients who underwent WEB treatment for an intracranial aneurysm from March 2014 to June 2020 in two high-volume centers were pooled. Operator experience was indexed by the number of WEB treatments performed previously. The primary endpoint was the overall complication rate. Secondary endpoints were long-term adequate (Raymond-Roy classification of 1-2.) angiographic occlusion, WEB-related complications, number of WEB not deployed, procedure duration, and radiation exposure (air kerma).

RESULTS

Among 237 patients (mean age 59.4 +/- 11.5 years) treated with WEB (median aneurysm diameter, 5.8 mm; interquartile range 4.5-7 mm), WEB-related complications occurred in 28 patients (11.8%) and adequate long-term occlusion was achieved for 154 aneurysms (86%). The median number of WEB treatment performed previously per operator was 20 (IQR, 9-41). The overall complication rate, WEB-related complication rate and aneurysm occlusion rate were not significantly correlated with WEB operator experience. There were also no significant correlations between the WEB operator experience and the number of WEB not deployed, procedure duration or radiation exposure.

CONCLUSION

There was no significant association between the number of WEB treatments previously performed per operator and any technical or clinical results after intracranial aneurysm treatment with WEB. These results imply a relatively short learning curve for this device in high-volume neurovascular centers.

Comparison of operating room variables, radiation exposure and implant costs for WEB versus stent assisted coiling for treatment of wide neck bifurcation aneurysms

BACKGROUND

The WEB device offers another option for treating wide neck bifurcation aneurysms (WNBA). The objective was to compare procedure variables, radiation and implant cost between WEB and stent assisted coiling (SAC) for WNBA.

METHODS

A retrospective comparison of similarly sized WNBA treated with SAC or WEB over 5-years was performed. The operating room (arrival-departure), anesthesia (intubation-extubation), procedure duration (puncture-closure), fluoroscopy time and radiation dose(m-Gy) were recorded from the patients' charts. Implant cost per case of all implants (stents, coils, WEB) that were opened whether deployed or not was captured including any coils used in the WEB cases. The implant cost represented the true cost incurred by the institution.

RESULTS

There were 46 WEB and 41 SAC cases with no significant difference in aneurysm size. There were more MCA and ACOMM (p = 0.005) and more ruptured aneurysms (p = 0.02) in the WEB group. Regarding procedure variables (hours:minutes): Operating room time WEB 2:31 (±0:37) versus SAC 3:41 (±0:50) (p < 0.0001); anesthesia duration WEB 2:05 (±0:31) versus SAC 3:13 (±0:51) (p < 0.0001) and procedure duration WEB 1:16 (±0:29) versus SAC 2:09 (±0:46) (p < 0.0001). Regarding radiation: Fluoroscopy time WEB 0:34 (±0:18) versus SAC 1:06 (±0:35) (p < 0.0001) and radiation dose WEB 2392(±1086)m-Gy versus SAC 3442 (±1528)m-Gy (p = 0.0007). The implant cost was $17,028(±$5,527) for the WEB versus $23,813 (±$7,456) for the SAC group (p < 0.0001).

CONCLUSION

The WEB group had significantly shorter operating room, procedure and anesthesia duration compared to the SAC group. The radiation dose and fluoroscopy time was lower for the WEB group. The total implant cost per case was significantly lower for the WEB versus the SAC group.

Treatment of ruptured intracranial aneurysms with the Woven EndoBridge device: a systematic review

The Woven EndoBridge (WEB) device is a barrel-shaped nitinol mesh deployed within the aneurysmal sac. The absence of metallic mesh in the aneurysm's parent vessel lumen obviates the need for potent antiplatelet therapy, making this device appealing for acutely ruptured aneurysms not amenable to clipping or coiling. To assess the literature regarding WEB treatment of these aneurysms, we performed a comprehensive systematic search of PubMed, MEDLINE, and EMBASE databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Keywords were combined with Boolean operators to increase search sensitivity and specificity ('woven endobridge device' AND 'ruptured'). Nine studies comprising 377 acutely ruptured aneurysms were included. Overall, 82.7% were wide-necked, 85.9% were located in the anterior circulation, and 26.9% of patients presented with poor subarachnoid hemorrhage grade. Intraprocedure and postprocedure complications occurred in 8.4% (95% CI 3.6% to 13.3%) and 1% (95% CI 0% to 2%), respectively. The post-treatment rebleeding rate was 0%. Rates of adequate occlusion (complete occlusion to neck remnant) and retreatment at last follow-up were 84.8% (95% CI 73% to 96.6%) and 4.5% (95% CI 2.2% to 6.8%), respectively. The favorable outcome rate (modified Rankin Scale score 0-2) was 62.2% (95% CI 53% to 71.4%); mortality was 13.6% (95% CI 9.7% to 17.6%). WEB treatment of acutely ruptured aneurysms results in high adequate occlusion rates, low perioperative complication rates, no rebleeding, and low recurrence requiring retreatment. This device is promising for acutely ruptured aneurysms not amenable to clipping or coiling, considering the lower need for antiplatelet regimens during the procedure or follow-up.

The outcomes of recurrent wide-necked intracranial aneurysms treated with the Woven EndoBridge (WEB): A retrospective bicenter study

BACKGROUND

The Woven EndoBridge (WEB) is a device for the treatment of intracranial wide-necked bifurcation aneurysms. The safety and effectiveness of WEB for intracranial aneurysms have both been evaluated in previous trials. Our aim was to study the outcomes of recurrent intracranial aneurysms (IAs) treated with WEB.

METHODS

Clinical and radiological outcomes of patients with a wide-necked aneurysm recurrence, which was treated with WEB device, were assessed. Imaging follow-up was performed with digital subtraction angiography and/or magnetic resonance angiography. Aneurysm occlusion was determined using by the Raymond-Roy Occlusion Classification (RROC). RROC 1 and RROC 2 were considered as adequate radiological outcome.

RESULTS

Twenty-two patients with 23 recurrent IAs were treated with WEB. Of which, 17 of recurrent IAs (74%) previously treated by coiling, three (13%) by clipping and three (13%) by WEB. The most common location of the recurrent IA was the middle cerebral artery (n = 10, 43%). Endovascular treatment with WEB alone was suitable for 20 recurrent IAs (87%). Ancillary devices were also used: coils in two (9%), and a stent in one (4%). Radiological follow-up results available for all patients (range: 3-60 months; median 24 months). Adequate occlusion (RROC I and II) was achieved in 20 recurrent IAs (87%). A hemorrhagic complication occurred 2 weeks post treatment in one patient (5%).

CONCLUSIONS

WEB could be an effective treatment with low rates of complications for challenging cases of recurrent wide-necked IAs.

Woven EndoBridge (WEB) Width at the Aneurysm Neck Level Affects Early Angiographic Aneurysm Occlusion

Purpose

Endovascular therapy with the Woven EndoBridge (WEB) device is a safe treatment approach, whereby neoendothelialization at the neck area is a crucial element for aneurysm occlusion. We hypothesized that WEB sizing at the aneurysmal neck level has an impact on early aneurysm occlusion.

Methods

Patients with short-term follow-up digital subtraction angiography following WEB treatment of unruptured aneurysms were included. Aneurysms were categorized according to the Bicêtre Occlusion Scale Score (BOSS) as adequately (BOSS 0, 0′, 1) or partially occluded (BOSS 2, 3, 1 + 3). The WEB device dimensions, including the average aneurysm diameter (AADi) and the average neck diameter (ANDi) as well as baseline patient characteristics were documented.

Results

In this study 75 patients with 76 aneurysms were included and 65 aneurysms showed adequate occlusion at short-term follow-up (86%). In univariable logistic regression analysis, smaller differences in WEB size to ANDi (D-ANDi) were significantly associated with adequate aneurysm occlusion (odds ratio, OR = 0.41, 95% confidence interval, CI 0.23–0.71, p = 0.002). Receiver operating characteristic (ROC) curve analyses displayed higher discriminative power for the D‑ANDi (AUC = 0.77, 95% CI 0.66–0.86, cut-off ≤2.9 mm) compared to the difference in WEB size to the average aneurysm diameter (D-AADi, AUC = 0.65, 95% CI 0.53–0.75, cut-off ≤1.0 mm).

Conclusion

Smaller differences between the WEB width and ANDi were associated with adequate early aneurysm occlusion and might thus have a higher impact on the results than the traditional device sizing considering the mean aneurysm diameter. D‑ANDi ≤2.9 mm served as an optimal cut-off to classify occlusion after WEB treatment at the short-term follow-up. Further external validation is warranted.

Supplementary Information

The online version of this article (10.1007/s00062-021-01034-0) contains supplementary material, which is available to authorized users.

WEB device for treatment of posterior communicating artery aneurysms

BACKGROUND

Woven EndoBridge (WEB) device treatment of wide-neck bifurcation aneurysms has proved to be safe and effective, but the use of these devices in sidewall aneurysms has been reported only in a small number of case series.

OBJECTIVE

To report our results in a cohort of consecutive patients in whom a WEB device was used as first-line treatment for posterior communicating artery (PComA) aneurysms.

METHODS

We conducted a retrospective analysis of a prospectively maintained database of PComA aneurysms treated with a WEB device in our institution from June 1, 2012 to November 15, 2020. Clinical and radiological findings were evaluated at immediate and last follow-up.

RESULTS

A total of 219 aneurysms were treated with a WEB device, including 15 PComA aneurysms in 15 patients, 10 of which were ruptured. Aneurysms were wide necked, with a mean aspect ratio of 1.6 (range 0.7-3.0) and a mean neck size of 4.2 mm (range 2.6-7.4 mm). No intraoperative rupture occurred and only one thromboembolic event was noted. Among the group with at least a 3-month digital subtraction angiography (DSA) follow-up, complete and adequate occlusion were obtained in 54% and 72%, respectively (average follow-up 13 months). Re-treatment was needed for two initially ruptured aneurysms. No procedure-related morbidity or mortality was reported.

CONCLUSION

This series suggests the high safety profile of WEB devices even when used in off-label indications. Treatment with these devices seems to be a valuable strategy for ruptured wide-neck PComA aneurysms, avoiding the need for antiplatelet medication. However, occlusion rates should be investigated in further larger studies.

Woven Endobridge Embolization Versus Microsurgical Clipping for Unruptured Anterior Circulation Aneurysms: A Propensity Score Analysis

BACKGROUND

Intrasaccular flow-disruption represents a new paradigm in endovascular treatment of wide-necked bifurcation aneurysms.

OBJECTIVE

To retrospectively compare Woven Endobridge (WEB) embolization with microsurgical clipping for unruptured anterior circulation aneurysms using propensity score adjustment.

METHODS

A total of 63 patients treated with WEB and 103 patients treated with clipping were compared based on the intention-to-treat principle. The primary outcome measures were immediate technical treatment success, major adverse events, and 6-mo complete aneurysm occlusion.

RESULTS

The technical success rates were 83% for WEB and 100% for clipping. Procedure-related complications occurred more often in the clipping group (13%) than the WEB group (6%, adjusted P < .01). However, the rates of major adverse events were comparable in both groups (WEB: 3%, clip: 4%, adjusted P = .53). At the 6-mo follow-up, favorable functional outcomes were achieved in 98% of the WEB embolization group and 99% of the clipping group (adjusted P = .19). Six-month complete aneurysm occlusion was obtained in 75% of the WEB group and 94% of the clipping group (adjusted P < .01).

CONCLUSION

Microsurgical clipping was associated with higher technical success and complete occlusion rates, whereas WEB had a lower complication rate. Favorable functional outcomes were achieved in ≥98% of both groups. The decision to use a specific treatment modality should be made on an individual basis and in accordance with the patient's preferences.

Delayed aneurysm rupture following treatment with the WEB embolization device

Delayed rupture of an aneurysm following WEB embolization has not yet been reported. We present a case of a multiply ruptured anterior communicating artery aneurysm treated via WEB embolization. A post-treatment CT scan confirmed no evidence of rebleeding during treatment. Four hours after treatment, the patient developed an acute, significant increase in intracranial pressure with bloody ventriculostomy output, with CT scan demonstrating new parenchymal and intraventricular hemorrhage. The aneurysm was subsequently treated via microsurgical clipping that did not identify an "uncovered" bleb or rupture source.

Intrasaccular Flow Disruption with the Woven EndoBridge for Narrow-Necked Aneurysms: A Safety and Feasibility Study

OBJECTIVE

The Woven EndoBridge (WEB) received U.S. Food and Drug Administration approval for endovascular treatment of wide-necked bifurcation aneurysms. We evaluated the feasibility, safety, and efficacy of the WEB for treatment of narrow-necked aneurysms.

METHODS

This multicenter study included 17 narrow-necked aneurysms, defined by a neck width <4 mm and a dome-to-neck ratio >2. Aneurysm characteristics, treatment strategies, technical success, complications, and angiographic outcomes were retrospectively assessed.

RESULTS

Aneurysm locations included the internal carotid artery (7 cases), anterior communicating artery (4 cases), middle cerebral artery (4 cases), and basilar artery (2 cases). The median aneurysm size was 7.4 mm with a median neck width of 2.3 mm. The technical success rate was 100%. There were no neurological complications. Angiographic control revealed complete and adequate occlusion in 13 of 15 (86.7%) and 14 of 15 (93.3%) cases, respectively, after 6 months and in 6 of 7 (85.6%) and 7 of 7 (100%) cases, respectively, after a median of 13 months. Two aneurysms were retreated with flow diverters.

CONCLUSIONS

WEB embolization of narrow-necked aneurysms was technically feasible and safe and might be considered as an alternative treatment option to conventional coiling in selected cases.

Recurrent and Residual Aneurysms After Woven EndoBridge (WEB) Therapy: What's Next?

The prevalence of recurrent and residual aneurysms following Woven EndoBridge (WEB) treatment is not insignificant. The goal of this systematic review was to evaluate retreatment methods for such aneurysms and their outcomes. PubMed, Embase, and Scopus databases were systematically searched, and results were reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Original studies reporting on aneurysms that were retreated after WEB were included. Sixteen studies (n = 901 aneurysms), of which three were prospective, reported on retreated aneurysms following initial WEB treatment. Of those 901 aneurysms, on average 18.7 ± 11.5% were recurrent or residual at the last follow-up and 10.7 ± 11% required some form of retreatment. When compared to WEB-IT (WEB Intra-saccular Therapy) data, retreated aneurysms were more likely to be large in size (p < 0.0001) and more likely to have been initially treated with the WEB dual-layer configuration. The mean age of those with retreated aneurysms was 58 ± 5.7 years old, and the mean size of aneurysm dome was 11.1 ± 5.5 millimeters. Majority (34.1%) of the aneurysms were located at the basilar apex. Retreatment modalities included coiling (20%), stent-assisted coiling (38.7%), additional WEB device (13.3%), flow diversion (16%), and clipping (12%). Majority of retreated cases had favorable outcomes, with 96.4 ± 13.4% of the cases demonstrating technical success and 90.5 ± 18.2% having adequate occlusion at the last follow-up. Our systematic review suggests that retreatment of recurrent and residual aneurysms after initial WEB treatment is feasible. Future prospective studies would be helpful in validating these results.

Intracranial aneurysm treatment with WEB and adjunctive stent: preliminary evaluation in a single-center series

Background

Intrasaccular flow disruption with WEB is a safe and efficacious technique that has significantly changed endovascular management of wide-neck bifurcation aneurysms (WNBAs). Use of stent in combination with WEB is occasionally required. We analyzed the frequency of use, indications, safety, and efficacy of the WEB–stent combination.

Methods

All aneurysms treated with WEB and stent were extracted from a prospectively maintained database. Patient and aneurysm characteristics, complications, and anatomical results were independently analyzed by a physician independent of the procedures.

Results

From June 2011 to January 2020, 152 patients with 157 aneurysms were treated with WEB. Of these, 17/152 patients (11.2%) with 19/157 aneurysms (12.1%) were treated with WEB device and stent. Indications were very wide neck with a branch emerging from the neck in 1/19 (5.2%) aneurysms and WEB protrusion in 18/19 (94.7%). At 1 month, no morbimortality was reported. At 6 months, anatomical results were complete aneurysm occlusion in 15/17 aneurysms (88.2%), neck remnant in 1/17 (5.9%), and aneurysm remnant in 1/17 (5.9%). At 12 months, there was complete aneurysm occlusion in 13/14 aneurysms (92.9%) and neck remnant in 1/14 (7.1%).

Conclusions

Combining WEB and stent is a therapeutic strategy to manage WNBA. In our series, this combination was used in 11.2% of patients treated with WEB, resulting in no morbidity or mortality with a high efficacy at 6 and 12 months (complete aneurysm occlusion in 88.2% and 92.9%, respectively).

Volume-based sizing of the Woven EndoBridge (WEB) device: A preliminary assessment of a novel method for device size selection

INTRODUCTION

Accurate sizing of the Woven EndoBridge (WEB) device is of critical importance as it determines procedural safety and successful occlusion of wide neck bifurcation aneurysms. The aim of this study was to assess the ability of aneurysm volume to assist in accurate WEB size selection.

METHODS

All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and October 2019 were identified for this retrospective study. Aneurysm volumes were calculated with auto-segmentation using a three-dimensional volume rendering program on an independent Syngo workstation (Siemens Healthineers AG). Pearson correlation coefficients were calculated for aneurysm auto-segmented volumes and WEB volumes, as well as for aneurysm height × width and WEB height × width. Follow-up angiographic outcomes were collected at 6-9 months post-procedure.

RESULTS

Twenty-nine aneurysms were evaluated by 3D rotational angiography. The correlation coefficient with WEB size was larger for auto-segmented aneurysm volumes (r = 0.979) compared to height × width measurements (r = 0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p = 0.0007). Follow-up angiography available in 13 subjects demonstrated an 85% complete aneurysm occlusion rate.

CONCLUSION

Aneurysm volumes are highly correlated with WEB volumes, with auto-segmentation volumes displaying statistically significant difference against conventional height by width measurements. These results suggest that volumetric measurements of aneurysm size provide a useful adjuvant measure to assist in appropriate size selection of the WEB device.

Woven EndoBridge device for ruptured aneurysms: perioperative results of a US multicenter experience

BACKGROUND

The Woven EndoBridge (WEB) device is approved in the USA for treatment of unruptured wide-neck bifurcation aneurysms. However, the safety and effectiveness of the WEB device in the treatment of ruptured intracranial aneurysms is not clear. We aim to evaluate the perioperative safety and effectiveness of the WEB device in patients with ruptured intracranial aneurysms.

METHODS

This retrospective study, conducted at eight centers in the USA, included patients with ruptured intracranial aneurysms treated with the WEB device in the setting of subarachnoid hemorrhage (SAH). Safety outcomes included intraoperative complications such as vessel perforation, thromboembolic events, and postoperative hemorrhagic or thromboembolic complications based on radiologic imaging. The primary effectiveness outcome was adequate (complete and neck remnant) aneurysm occlusion, according to the Raymond-Roy classification.

RESULTS

A total of 91 patients with 94 ruptured intracranial aneurysms were included (mean age 57.7±15.2 years; 68.1% women; 82.9% wide-necked). Aneurysms were located in the anterior communicating artery (42/94, 44.6%), middle cerebral artery (16/94, 17%), and basilar artery (15/94, 16%). Adequate occlusion was achieved in 48.8% (41/84) and 80.0% (40/50) at discharge and last follow-up (mean of 3.4 months), respectively. At discharge, procedural-related morbidity was 3.3% (3/91) and there was no procedure-related mortality. No re-rupture or delayed aneurysm rupture was observed.

CONCLUSIONS

This study demonstrates the perioperative safety and effectiveness of the WEB device for the treatment of patients with ruptured intracranial aneurysms in the setting of SAH, with low periprocedural morbidity and mortality. Long-term follow-up is warranted.

Endovascular treatment of basilar tip aneurysms in the era of endosaccular flow disruption: a comparative study

Purpose

This study aims to compare endosaccular flow disruptor (EFD) for treatment of basilar tip aneurysm (BTA) with coiling in terms of safety and efficacy.

Methods

We retrospectively reviewed patients treated with an EFD for BTAs at our institution between 2013 and 2019 to standard coiling from the same period (control group). Patient demographics, aneurysm characteristics, procedural data, complications and clinical and angiographic outcome were compared between groups.

Results

Twenty-three (56%) patients were treated with an EFD and eighteen (44%) patients were treated with coiling. Average aneurysm size was 8 mm in the EFD group and 6.9 mm in the coiling group, respectively (P = 0.2). Average fluoroscopy time, treatment DAP and air kerma were 33 min, 76 Gycm² and 1.7 Gy in the EFD group and 81 min, 152 Gycm² and 3.8 Gy in the coiling group, respectively (P < 0.001). In the EFD group, clinically relevant thromboembolic complications occurred in one patient (4%) vs. in 5 patients (28%) in the coiling group (P = 0.07). In each group, 4 patients had an unfavourable outcome at discharge (P = 0.7). Adequate occlusion rates were 96% in the EFD group and 100% and coiling group. Six (26%) patients were prescribed long-term antiplatelet therapy in the EFD group vs. eleven (61%) patients in the coiling group (P = 0.02).

Conclusion

Both treatment concepts provided similar technical success and safety. However, procedure time, radiation exposure and a need for long-term antiaggregation were lower with EFD.

Recent advances in stent-assisted coiling of cerebral aneurysms

INTRODUCTION

Stent-assisted coiling (SAC) of intracranial aneurysms paved the way for endovascular coiling of wide-neck and bifurcation aneurysms, improving rates of aneurysm obliteration and recurrence. In this review, we provide a comprehensive review of the most recent advances related to stent-assisted coiling of intracranial aneurysm.

AREAS COVERED

The authors have made an attempt to cover the inception, applications, and limitations of SAC of intracranial aneurysms. Special focus is given to 1) the current and recently introduced SAC techniques, 2) most recent advances in device technology, and 3) outcome data for the discussed techniques and devices. The authors also discuss the potential future direction of SAC.

EXPERT OPINION

technical refinements in the field of SAC should continue to focus on device development and addressing the limitations of SAC, namely aneurysm recurrence and need of antiplatelet agents. Although the recurrence rate of SAC has not been shown to be inferior to flow diverters, the use of intrasaccular and intravascular flow diverters are likely to expand in the future at the expense of SAC.

Low-Profile Laser-Cut Stents for Endovascular Treatment of Intracranial Aneurysms : Incidence, Clinical Presentation and Risk Factors of Thromboembolic Events

PURPOSE

Low-profile intracranial stents are characterized by a miniaturized design that enables deployment via a 0.0165″ or 0.017″ internal diameter microcatheter, which is typically intended for coil delivery. This study analyzed the incidence, clinical relevance and risk factors of thromboembolic events (TEE) occurring during low-profile stent-assisted coiling of intracranial aneurysms.

METHODS

This was a retrospective, multicenter analysis of consecutive patients who underwent stent-assisted aneurysm coiling (SAC) with the laser-cut Acandis Acclino and Neuroform Atlas stents. The study evaluated the incidence of symptomatic and asymptomatic TEEs and the impact on functional outcome. Risk factors for TEEs were determined by univariate and bivariate logistic regression analyses.

RESULTS

Among 131 procedures (mean patient age 56.5 ± 12.8 years, mean aneurysm size: 6.7 ± 3.9 mm) TEEs occurred in 14 cases (10.7%) of which 2 patients (1.5%) developed ischemic stroke, while the remaining TEEs remained asymptomatic. Multivariate analysis revealed Y‑stenting as potential risk factor for TEEs (odds ratio: 3.9, 95% confidence interval: 1.0-16.5; p = 0.08).

CONCLUSION

The use of SAC with low-profile intracranial stents is associated with a favorable safety profile; however, Y‑stenting may carry an increased risk of TEEs, which needs to be considered during treatment planning.

Identifying Predictors for Aneurysm Remnants After Clipping by Morphometric Analysis and Proposal of a Novel Risk Score

OBJECTIVE

Although the risk of aneurysm remnants after microsurgical clipping is generally low, complete aneurysm occlusion is not always guaranteed. We performed a morphometric analysis of intracranial aneurysms to identify predictors for aneurysm remnants and to propose a novel risk score.

METHODS

This is a retrospective, single-center analysis of consecutive patients with ruptured and unruptured aneurysms who underwent microsurgical clipping and postoperative digital subtraction angiography between 2010 and 2018. Based on preoperative rotational angiography, distinct morphologic aneurysm characteristics were determined and correlated with postoperative angiographic results. Factors predictive in the univariate and multivariate analyses were determined to establish a risk score for postoperative remnants after aneurysm clipping.

RESULTS

Among 140 patients with 166 clipped aneurysms, aneurysm remnants were present in 19.9%. In the multivariate analysis, ruptured aneurysm status (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.7-36; P < 0.01) and increased aspect ratio (OR, 1.9; 95% CI, 1.0-4.0; P = 0.07) were associated with postoperative aneurysm remnants. Anterior communicating artery location (P = 0.02), internal carotid artery location (P = 0.06), increased aneurysm inclination angle (P < 0.01), and irregular aneurysm shape (P = 0.07) were further predictors for aneurysm remnants in the univariate analysis. These factors were weighted and included into a risk sum score for postoperative aneurysm remnants (range, 0-8 points), which performed with good accuracy (area under the curve = 0.807).

CONCLUSIONS

After external validation of the proposed risk score, it could help identify cases requiring angiographic control after aneurysm surgery.

Long-term Angiographic Results of the Low-profile Acandis Acclino Stent for Treatment of Intracranial Aneurysms : A Multicenter Study

PURPOSE

The low-profile Acandis Acclino is a self-expandable nitinol microstent for stent-assisted coiling of intracranial aneurysms. This article reports long-term clinical and angiographic outcome in a multicenter setting.

METHODS

In this study 98 consecutive patients (mean age 55.4 ± 13.5 years) were treated with the Acclino for 98 aneurysms (28 unruptured, 20 recurrent, 50 ruptured) at 3 German tertiary care centers within a 6-year period. The technical success, complications, clinical outcome and angiographic results were retrospectively analyzed.

RESULTS

The technical success rate was 100% with immediate complete occlusion achieved in 89.8% of the patients. Among 65 patients (66.3%) available for a 6‑month follow-up, complete and near-complete occlusion rates were 92.3% and 98.5%, respectively. In 38 patients (38.8%) with long-term follow-up (mean: 21 months), complete and near-complete occlusion were achieved in 81.2% and 89.5%, respectively. Aneurysm recurrence between mid-term and long-term follow-up was observed in 14.3%. The retreatment rate was 11.3%. There were three thromboembolic events (3.1%), of which one resulted in ischemic stroke (1.0%). For unruptured aneurysms, the procedural and device-related morbidity rates were 2.1% and 0%, respectively.

CONCLUSION

In the present study, the Acclino was associated with a low risk of thromboembolic complications and high aneurysm occlusion rates at long-term follow-up. Due to incomplete angiographic follow-up in this series, prospective studies will be necessary to confirm the results.

The RISE trial: A Randomized Trial on Intra-Saccular Endobridge devices

BACKGROUND

Wide-necked bifurcation aneurysms (WNBA) are a difficult subset of aneurysms to successfully repair endovascularly, and a number of treatment adjuncts have been designed to improve on the results of coiling, including stenting and flow diversion of the parent vessel. Surgical clipping is commonly performed for certain WNBAs, such as middle cerebral aneurysms, in some centres. Intra-saccular flow diversion (ISFD) using the Woven Endo-Bridge (WEB) or similar devices, has been developed as a new endovascular alternative to coiling for WNBAs. Meta-analyses of case series suggest satisfactory results, both in terms of safety and efficacy, but in the absence of randomized evidence, whether ISFD leads to better outcomes for patients with WNBA remains unknown. There is a need to offer ISFD within the context of a randomized care trial.

METHODS

The proposed trial is a multicentre, randomized controlled care trial comparing ISFD and best conventional management option (surgical or endovascular), as determined by the treating physician prior to randomized allocation. At least 250 patients will be recruited in at least 10 centres over a four-year period, and followed for one year, to show that ISFD can increase the incidence of successful therapy from 75 to 90% of patients, defined as complete or near-complete occlusion of the aneurysm AND a good clinical outcome (mRS ≤ 2) at one year. The trial will be followed by an independent data safety monitoring committee to assure the safety of participants.

CONCLUSION

Introduction of intra-saccular flow diversion can be accomplished within a care trial context.

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

BACKGROUND AND PURPOSE

The Woven EndoBridge 17 has recently been introduced to the market for facilitated endovascular treatment of small bifurcation aneurysms (≤7 mm) with low-profile microcatheters. We compared the Woven EndoBridge 17 with its predecessor versions in terms of procedural safety and feasibility.

MATERIALS AND METHODS

This was a multicenter review of aneurysms ranging from 3 to 7 mm treated with the Woven EndoBridge between 2011 and 2019. Aneurysm characteristics, procedural parameters, and complications were retrospectively compared between treatment with the Woven EndoBridge 17 and a control group that was treated with its predecessor versions, using inverse probability of treatment weighting.

RESULTS

Thirty-eight aneurysms treated with a Woven EndoBridge 17 (mean size, 4.9 ± 1.5 mm) and 70 treated with a predecessor version of the Woven EndoBridge 17 (mean size, 5.6 ± 1.4 mm) were included. The predecessor version of the Woven EndoBridge 17 had a higher failure rate (10.3%) than the Woven EndoBridge 17 (0%, P = .05). Additional stent placement was performed more often with the predecessor version of the Woven EndoBridge 17 (10.0%) than with the Woven EndoBridge 17 (2.6%, adjusted P = .005). The predecessor version of the Woven EndoBridge 17 was associated with a higher thromboembolic event rate (14.3%) than the Woven EndoBridge 17 (5.3%, adjusted P = .002). Neurologic complications (Woven EndoBridge 17: 2.6%; predecessor version of the Woven EndoBridge 17: 2.9%, adjusted P = 1.0) and immediate complete aneurysm occlusion rates (Woven EndoBridge 17: 57.9%; predecessor version of the Woven EndoBridge 17: 54.3%, adjusted P = .21) did not differ significantly between groups.

CONCLUSIONS

In the current study, the Woven EndoBridge 17 was associated with a potentially lower thromboembolic event rate than the predecessor version of the Woven EndoBridge 17, without compromising the immediate aneurysm occlusion rate. Long-term clinical and angiographic outcome analysis will be necessary to draw a definite conclusion.