The Need for Long-term Follow-up in Completely Occluded Aneurysms at 6 Months After WEB Device Treatment: Results of the Worldwideweb Consortium

Introduction: The Woven EndoBridge (WEB) (Microvention, Aliso Viejo, California) device has been widely used to treat intracranial wide neck bifurcation aneurysms. Initial studies have demonstrated that approximately 90% of patient exhibit same or improved aneurysm occlusion long term after the initial 6-month follow up. We aimed to assess the yield of long-term follow-up in aneurysms that have achieved complete occlusion at 6 months. We also compared the predictive value of different imaging modalities used.

Methods: This is a review of a prospectively maintained database across 13 academic institutions. We included patients with previously untreated cerebral aneurysms embolized using the WEB device who achieved complete occlusion at first follow-up and had available long-term follow-up. Logistic regression was used to test covariates predictive of long-term aneurysm obliteration and retreatment. Confounders were assessed through generalized linear regression analysis.

Results: A total of 95 patients with a mean age of 61.611.9 years were studied. The mean neck diameter and height were 3.91.3 mm and 6.01.8 mm, respectively. The mean time to first and last follow-up was 5.41.8 and 14.1 12.9 months, respectively. Out of all the aneurysms that were completely occluded at 6 months, 84 (90.3%) showed complete occlusion at the final follow-up, 5 (5.4%) showed near-complete occlusion and in 4 (4.3%) cases aneurysm residual was observed. As such the positive predictive value (PPV) of complete occlusion at first follow was 88.4%. Importantly this did not differ between DSA, MRA or CTA.

Conclusion : The study underlines the importance of repeat imaging in patients treated with the WEB device even if complete occlusion is achieved short term. Follow-up can be performed using DSA, MRA or CTA with no difference in PPV.