Propensity Score-matched Comparison of WEB 17 and WEB 21 with 4-7 mm Device Sizes for the Treatment of Unruptured Intracranial Aneurysms.

Purpose: The WEB 17 system represents the fifth generation of Woven Endobridge (WEB) flow disruptors and features a low profile with fewer wires than its predecessor, the WEB 21. The present study compares the safety and efficacy of the WEB 17 and WEB 21 for the treatment of unruptured cerebral aneurysms with 4-7 mm device sizes, which were available for both systems.

Methods: Patient and aneurysm characteristics, complications, clinical outcome and angiographic results were retrospectively analysed. 1:1 propensity score matching was performed to adjust for minor baseline differences between the groups.

Results: Sixty aneurysms treated with WEB 21 and 90 with WEB 17 were included. The overall failure rate (deployment failure and adjunctive stent) was significantly higher with WEB 21 (16.7%) than with WEB 17 (3.3%, p < 0.01). The rates of neurological events between WEB 21 (6.7%) and WEB 17 treatment (1.1%) were not significantly different (p = 0.08). Also, procedural morbidity was comparably low in both groups (WEB 21: 3.3%, WEB 17: 0%, p = 0.16). The rates of complete/adequate occlusion at follow up were 69.7%/86.4% for WEB 17 vs. 80.4%/91.3% for WEB 21 at short-term (p = 0.27), and 64.5%/83.9% vs. 75.9%/86.2% at mid-term (p = 0.41), respectively. Propensity score matching confirmed the results of the unmatched series.

Conclusion: WEB 17 and WEB 21 had a similar safety and efficacy profile, but WEB 17 was associated with an improved feasibility. Prospective studies with long-term follow-up will define the full potential of the WEB 17 system.