Safety results from the treatment of 109 cerebral aneurysms using the Woven EndoBridge technique: preliminary results in the United Kingdom

OBJECTIVE The Woven Endobridge (WEB) device has been in clinical use for the treatment of brain aneurysms for the past 4 years. Observational studies to assess clinical outcome and related complications have been published. Clear evidence is required to better understand the safety profile of the WEB device. The authors here present a multicenter series that provides a detailed safety analysis focused on patient selection, procedural events, and technical issues of treated patients throughout the United Kingdom (UK). METHODS A nationwide password-protected database was set up to collect anonymous information across the UK (14 centers). Complications and clinical outcome were analyzed for the initial 109 patients (112 procedures). An independent root cause analysis classified the complications into groups (procedural, disease, device, ancillary device, and other). The modified Rankin Scale (mRS) was used as a marker of clinical outcome. RESULTS Each of the 109 patients had 1 aneurysm suitable for WEB treatment (109 aneurysms). Three patients had 2 procedures, making a total of 112 procedures performed. Eight procedures were abandoned because of access issues; 2 patients went on to have a successful procedure. All 109 patients had a preprocedure and discharge mRS scores recorded. One hundred patients had a recorded mRS score from a > 3-month follow-up. Deployment of the WEB device was successful in 103 (94.5%) of 109 patients and 104 (92.9%) of 112 procedures. One patient had 2 successful WEB procedures on separate occasions. Patients without a successfully implanted WEB device were included in the analysis. Selection analysis showed that the average patient age was 56.5 years among 34 men and 75 women. The percentage of incidental aneurysms was 58.7%, acute 16.5%, symptomatic 18.3%, and recurrent 6.4%. Further results analysis showed that 40 (36.7%) of 109 patients had recorded adverse events, including those unrelated to the WEB device. Events that could be related to the WEB device numbered 17 (15.6%) among the 109 patients. Two patients with device-related complications were symptomatic. Overall, 11 patients (10.1%) had persistent clinical sequelae. Thromboembolism was the most prevalent event, affecting 15.6% of the patients (17 of 109), and 6.4% of the patients (7 of 109) with a thromboembolism were symptomatic. Overall mortality before discharge was 0% and at the > 3-month follow-up was 5% (5 of 100 patients). Morbidity was defined as an mRS score increase to > 2. Overall morbidity at discharge was 1.8% (2 of 109) and at the > 3-month follow-up was 6% (6 of 100). No device-related morbidity or mortality was associated with this group. CONCLUSIONS The UK data show that the WEB device is safe for clinical use. Thromboembolic complication adds a risk that should be minimized with appropriate anticoagulation and correct sizing of the device. There is scope for further evaluation and standardization of an anticoagulation regimen for the WEB device.