Risk factors for recanalization of basilar tip aneurysm after endovascular treatment: a retrospective cohort study

Objectives Endovascular treatment (EVT) of basilar tip aneurysms (BTAs) is arduous because of the lesions' angioarchitecture and the relatively high recanalization rate after EVT. In this study, we aimed to report the clinical characteristics of BTAs and evaluate the incidence of and risk factors for recanalization. Methods One hundred twenty-five patients with BTAs (11 ruptured, 114 unruptured) treated with EVT between 2009 and 2019 at one institution were retrospectively reviewed. Among them, 113 patients were included in statistical analyses. The anatomical parameters of the aneurysms and clinical data were analyzed. Univariate (chi-square test and t-test) and multivariate (multiple logistic regression) analyses were performed to identify risk factors for recanalization. Results Recanalization of the BTA occurred in 15 patients (13.3%). One patient (0.9%) was retreated endovascularly. The mean follow-up duration was 49.8 months. Neck size, posterior cerebral artery (PCA) angle, maximum diameter, and the rupture rate differed significantly between the recanalization and non-recanalization groups (P=.007, P<.001, P=.006, and P=.048, respectively). The maximum diameter (odds ratio, 1.483 per mm; 95% confidence interval, 1.145-1.919; P=.003) and PCA angle (odds ratio, 1.020 per degree; 95% confidence interval, 1.001-1.039; P=.036) were independently associated with recanalization. Conclusions Of all investigated BTAs, 96.8% were wide-neck aneurysms. The recanalization rate of BTAs after EVT was 13.3%. The PCA angle and maximal aneurysmal diameter were independently associated with recanalization; no associations were observed regarding vertebral artery dominance or modality of treatment. As such, BTA patients with wide PCA angles should be carefully monitored over time.