(AS1) Intra-operative Predictors of Long-term Obliteration and Retreatment of Cerebral Aneurysms Following WEB Device Embolization: Results of the Worldwideweb Consortium

Introduction: The Woven EndoBridge (WEB) device has added to the armamentarium of aneurysm treatment and has demonstrated adequate long-term occlusion in 80-90% of cases. We aimed to identify early predictors of long-term obliteration and retreatment based on patient and aneurysm characteristics as well as intra-operative findings for aneurysms treated with the WEB device.

Methods: This is a retrospective analysis of a prospective database across 22 institutions. All aneurysms treated solely with a WEB device with available intra-procedural data and long-term follow-up were included. Logistic regression was used to test covariates predictive of long-term aneurysm obliteration and retreatment. Confounders were assessed through generalized linear regression analysis.

Results: We studied 763 patients with a mean age of 59.911.7 years and comprised of 66.8% women. Mean aneurysm maximal diameter was 6.922.43 mm with 3.971.4 mm neck. In 29.2% of cases aneurysm occlusion was observed intra-operatively and contrast stasis was observed in 90.3% of non-occluded aneurysms. At final-follow-up, complete occlusion was achieved in 497 (71.5%) patients and retreatment was required for 56 (7.4%) of patients. On multivariable analysis smoking, maximal aneurysm diameter and the presence of an aneurysm wall branch are negative predictors of complete occlusion (OR: 0.06, 0.8 and 0.43, respectively) and increase the chances of retreatment (OR: 1.7, 1.2 and 3.8, respectively). Intra-procedural occlusion resulted 2.9-fold increase in long term occlusion rate and 10-fold decrease in retreatment rate (p < 0.001) offering specificity of 87% and positive predictive value of 85% for long-term.

Conclusion : This is the largest cohort of patients treated with the WEB device and demonstrates that intraprocedural obliteration but not stasis can be used to predict the chance of long-term aneurysm occlusion and need for retreatment after embolization with a WEB device. Smoking, aneurysm size and aneurysm wall branch are associated with decreased chance of successful treatment.