Predictors of thromboembolism during coil embolization in patients with unruptured intracranial aneurysm

Objectives: To identify the incidence of thromboembolic complications based on magnetic resonance imaging (MRI) and to explore the potential risk factors for thromboembolism (TE) during the periprocedural period of elective coil embolization for unruptured intracranial aneurysms. Methods: We retrospectively reviewed all aneurysm cases treated with coil insertion between January 2008 and March 2011. Two hundred eighty-two coiling procedures for unruptured aneurysms were included in this study. The patients' demographic characteristics were documented and records reviewed for abnormalities in diffusion-weighted imaging (DWI) seen on post-procedure MRI, intraoperative thrombus formation, and clinical signs of stroke. Results: Overall, there were 87 (30.9 %) procedure-related complications in 282 aneurysms treated: 2 (0.7 %) procedural ruptures, 5 (1.8 %) symptomatic infarctions, and 80 (28.3 %) asymptomatic infarctions. Thromboembolic events during the procedure were observed more often in the the hyperlipidemia group (32/71 aneurysms, 45.1 %) than in the normal lipid profile group (39/196 aneurysms, 25.6 %; p = 0.002; chi-squre test). The coiling technique and size of the aneurysm were also associated with TE (p < 0.001 and p = 0.004). Conclusion: Hyperlipidemia seems to be associated with a significant increase in the rate of thromboembolic events. In preventive procedures, modifiable risk factors should be managed to reduce complications. Although permanent deficits are rare, the high rate of thromboembolic events suggests that improvements in the technique, such as the addition of antiplatelet agents and the development of new embolic materials, are necessary.