Collateral Scores and Outcomes after Endovascular Treatment for Basilar Artery Occlusion

Basilar artery occlusion (BAO) is a rare stroke subtype with high mortality rates. Best BAO reperfusion strategy is still controversial.

We aim to describe outcomes of BAO patients submitted to mechanical thrombectomy (MT) in a comprehensive stroke center in Brazil and analyze which previous published computed tomography angiography (CTA) collateral score better predict functional outcomes.

Retrospective analysis of consecutive BAO patients. CTA was used to evaluate the posterior circulation collateral score (PC-CS), the basilar artery on CTA score, and for the presence of posterior communicating arteries. A favorable outcome was defined as modified Rankin Score ≤3 at 90-days. After univariate analyses, multivariate logistic regression was used to identify if any collateral score independently predicts favorable outcomes.

Between January 2011 and April 2017, 27 (85% male) BAO patients with median NIHSS 26 (IQR 15-32) were identified. Twenty-five (93%) patients were treated with MT devices, and only 2 (7%) patients were treated with angioplasty and stenting. Successful recanalization rate was 85%, and only 1 (3.7%) patient had symptomatic hemorrhagic transformation. Favorable outcomes were reached in 10 (37%) patients. In univariate analysis, female sex, NIHSS, Glasgow coma scale, mild-to-moderate symptoms on admission, onset-to-groin time, and PC-CS predicted favorable outcomes. In multivariate analysis, PC-CS (OR 1.69; 95% CI 1.10-2.60; p = 0.016) and NIHSS (OR 0.84; 95% CI 0.77-0.93; p = 0.001) remained the only independent predictors of favorable outcomes. The PC-CS AUC was 0.80 (95% CI 0.62-0.98; p = 0.012).

MT is a promising strategy for BAO treatment. Among collateral scores, PC-CS was the only independent predictor of favorable outcomes in the present study.