LAUSR

Objective To ascertain the long-term durability of coiled aneurysms completely occluded at 36 months during follow-up given the potential for delayed recanalization. Methods As a retrospective review, we examined 299 patients with 339 aneurysms, all completely occluded at 36 months in follow-up images obtained between 2011 and 2013. Medical records and radiologic data acquired during extended monitoring (mean, 74.3±22.5 months) were retrieved, analyzing incidence (including average annual risk) and risk factors of delayed recanalization. Results A total of five coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during continued long-term surveillance (1081.9 aneurysm-years), two surfacing within 60 months and three developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In multivariate analysis, second embolization for recurred aneurysm (HR=22.088, p=0.003) independently correlated with delayed recanalization. Conclusion Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months post-embolization proved to be stable in extended observation. Therefore, it is reasonable to suspend imaging surveillance of coiled aneurysms after 3 years in the absence of demonstrable recanalization. However, recurrent aneurysms were predisposed to delayed recanalization. Disclosures Y. Cho: None.