Consideration of Recanalization Risk Factors after Coil Embolization for Intracranial Aneurysms

Abstract

We retrospectively reviewed our own experiences of coil embolization for intracranial aneurysms regarding recanalization. Between July 2001 and December 2007, a total of 740 patients underwent coil embolization at our institution or affiliated hospitals. Among those, 271 patients with 278 aneurysms who underwent follow-up cerebral angiography more than 12 months after the initial treatment were the subjects of this study. Immediate angiographic results showed complete occlusion in 72.4%, residual neck in 14.0%, and residual filling in 13.6%. Mean follow-up periods were 21.7 and 20.6 months for ruptured and unrup-tured aneurysms, respectively. The overall recanalization rate was 29.4% (major recurrence 12.6%, minor recurrence 16.8%). Previous rupture and morphology of wide-neck (≥4 mm) or large size (≥10 mm) and location of posterior circulation were the significant risk factors of recanalization (P 0.05). Gender, immediate angiographic results and embolization techniques were not statistically significant. Posttreatment bleeding from the coil-embolized aneurysms occurred in only 0.4% of the cases during the study period. Coil embolization of intracranial aneurysms is proving to be a safe method of protecting aneurysms from rupture. However, endovascularly treated patients, particularly those with recanalization risk factors, should undergo long-term follow-up.