Original ArticleAnalysis of Predictors and Probability of Aneurysm Occlusion in the Internal Carotid Artery After Treatment with Pipeline Embolization Device

BackgroundAlthough the Pipeline Embolization Device (PED) has proved to be an excellent option for internal carotid artery (ICA) aneurysms, the rate of occlusion remains difficult to predict and factors associated with aneurysm occlusion are not well elucidated. This study aimed to investigate predictors and the rate of occlusion for aneurysms along the ICA.MethodsA total of 117 saccular ICA aneurysms treated with the PED were studied. Occlusion rates were divided among 4 groups: group A [lesions >10 mm in the proximal ICA (petrous to the superior hypophyseal segments)]; group B (lesions <10 mm in the proximal ICA); group C [lesions >10mm in the distal ICA (posterior communicating segment to the ICA bifurcation)]; and group D (lesions <10 mm in the distal ICA). Predictors of aneurysm occlusion were entered into a multivariate Cox regression analysis.ResultsThe median time to aneurysm occlusion was 8 months in group A (95% confidence interval [CI], 7.0-9.1), 5.2 months in group B (95% CI, 4.5-6.0), 6.9 months in group C (95% CI, 6.5-7.2), and 10.2 months in group D (95% CI, 6.9-13.6) (P = 0.045). There was a statistically significant difference between the probability of aneurysm occlusion in group B compared with distal ICA aneurysms (P = 0.02). Small proximal ICA aneurysms were more likely to occlude over time compared with other aneurysm groups (hazard ratio, 1.76; 95% CI, 1.07-2.9; P = 0.02).ConclusionsThe rate of occlusion after PED is highest for small proximal ICA aneurysms and the probability of occlusion is lower for distal ICA aneurysms.