Follow-Up Outcomes After Re-Embolization for Recanalized Aneurysms After Initial Coiling: Further Recurrence Rates and Related Risk Factors

Although it is well known that coiled aneurysms can recanalize over time, long-term outcomes of re-embolization for recurred aneurysms have not been adequately investigated. We studied the retreatment outcomes of re-embolized aneurysms during follow-up monitoring and assessed the risk factors related to further recanalization. A total of 129 patients with 133 aneurysms were retrospectively reviewed. Each aneurysm was subjected to re-embolization because of major recanalization after initial coil embolization and underwent midterm and extended monitoring after retreatment. Cumulative medical records and radiologic data were assessed. Repeat recurrence rates and related risk factors were assessed by binary logistic regression analysis. A total of 47 aneurysms (35.3%) showed re-recanalization at 6 months after re-embolization, with 17 and 30 instances of minor and major recanalization, respectively. Multivariate analysis indicated that posterior circulation (hazard ratio [HR], 6.129; P = 0.010), large aneurysm (>7 mm) (HR, 13.598; P < 0.001), and incomplete occlusion at the second coiling (HR, 9.975; P = 0.001) were significant factors for repeat recanalization. Of 86 aneurysms showing complete occlusion at the midterm, 76 were further evaluated (≥12 months), showing 18 aneurysms (23.7%) of delayed re-recanalization during a follow-up of 230.1 aneurysm-years. Of 15 aneurysms with minor recanalization at 6 months, 6 (40.0%) progressed to major recanalization during a follow-up of 44.0 aneurysm-years. Most re-coiled aneurysms (64.7%) showed complete occlusion at the 6-month follow-up. However, posterior circulation, large aneurysm (>7 mm), and incomplete occlusion at the second coiling were risks for further recanalization. The midterm and delayed re-recanalization rates of the re-embolized aneurysms seem to be higher than those of the initial aneurysms. •There have been few studies that have investigated the follow-up outcomes of re-embolized aneurysms.•The majority of recoiled aneurysms (64.7%) displayed complete occlusion at the 6-month follow-up.•Posterior circulation, large aneurysm, and incomplete occlusion at the 2nd coiling were risks for re-recanalization.•The recanalization rates (48.8%) of the re-embolized aneurysms seem to be higher than those of the initial aneurysms.