Introduction/Purpose WEB allows treatment of wide-neck bifurcation aneurysms. WEB 17 has been developed to be delivered through low profile 17-microcatheter, allowing to make easier the treatment and to manage smaller aneurysms. The WEB device has demonstrated its efficacy and safety, for both unruptured and ruptured aneurysms. The CLEVER objective has been set up to provide safety and efficacy data on the WEB 0.017 device in treatment of bifurcation aneurysms.

These results report description of the efficacy and safety results at 12 months.

Material/Methods CLEVER study is an observational, prospective and multicenter study conducted in 17 European sites (France, Germany, Hungary, Finland, United Kingdom) using the WEB 0.017 device, the last developed model of WEB product family with a lower profile. The data collected are 100% monitored and the primary endpoints independently evaluated. Patients’data are collected from baseline to 12-month post-treatment with evaluation visits at discharge, 1, 6 and 12-months post-treatment. Occlusion results are assessed independently by a Corelab and adverse events are adjudicated by a Clinical Events Committee. Study design allows to analyze the study results for the full population as well as separately for ruptured and unruptured aneurysm. An intention treat analysis is performed for the safety population, and sample size calculation is based on objective performance approach for safety and efficacy rates.

Results From March 2019 to February 2021, 163 patients (mean age, 58.1 years; 68.1% of women) with 103 unruptured aneurysms and 60 ruptured aneurysms were enrolled.

The aneurysms treated were ranging from 2 to 9.2mm (mean maximum sac width = 5.0mm) and dome-to-neck ratio was < 2 in 95.7% of cases. The WEB procedure was completed with success in 163 patients (100%). 147/163 (90.2%) of aneurysm were treated only with WEB implant and adjunctive implanted devices were used in 6/163 (3.7%) of cases. The primary safety endpoint was the proportion of patients with death of any nonaccidental cause or any major stroke (defined as ischemic or hemorrhagic stroke resulting in an increase of 4 points or more on the NIHSS) within the first 30 days after treatment or major ipsilateral stroke or death due to neurologic cause from day 31 to the 1 year after treatment. Four major strokes on 3/163 patients (1.8%) met the primary safety endpoint. The WEB related mortality rate at 12 months was 0%. The primary efficacy endpoint, defined as the 12-month rate of adequate occlusion without retreatment, was 82.2% (120/146 patients). A detailed description of events reported from per procedure up to 30 days will be provided with a specific attention to the aneurysm initial presentation (ruptured vs unruptured).

Conclusion These results show good efficacy and safety results at 12 months month, and no WEB related mortality at 12 months. These data confirm the safety and efficacy of WEB 0.017 use in intracranial aneurysm treatment, unruptured as well as ruptured, and are consistent with the results published up to date.

Disclosures L. Spelle: 1; C; Philips. 2; C; Microvention, Stryker, Medtronic, Balt, Phenox. C. Cognard: 2; C; Stryker, Medtronic, Mivi, Cerenovus, Microvention. I. Szikora: 2; C; Stryker, Cerenovus, Medtronic, Microvention, Brainomix. F. Wodarg: 2; C; Microvention, Stryker, Cerus Endovascular, Balt, Johnson & Johnson, Acandis. V. Costalat: 2; C; Stryker, Medtronic, Microvention. D. Herbreteau: 2; C; Microvention. S. Fischer: 2; C; Rapid Medical, Microvention, Phenox, Stryker, Kaneka. M. Möhlenbruch: 1; C; Balt, Medtronic, Microvention, Stryker. 2; C; Siemens. C. Papagiannaki: 2; C; Medtronic, Microvention, Stryker. J. Klisch: 2; C; Microvention, Phenox, Cerus. R. Rautio: 2; C; Medtronic, Stryker, Microvention. A. Berlis: None. J. Downer: 1; C; Stryker, Microvention, Oxford Heartbeat. 2; C; Microvention. 3; C; Microvention, Stryker, Medtronic. M. Bester: 2; C; Microvention, Acandis. S. Velasco: None. T. Liebig: 2; C; Cerus endovascular, Stryker, Medtronic, Phenox, Microvention. J. Byrne: 1; C; Microvention. 2; C; Microvention, Oxford Endovascular Ltd. 4; C; Oxford Endovascular Ltd. L. Pierot: 2; C; Balt, Microvention, Phenox, Perflow, Vesalio.