Recanalization of basilar artery occlusion during inter-hospital transfer for thrombectomy.

Background: Patients with acute ischemic stroke and a large vessel occlusion admitted to non-endovascular capable centers frequently require inter-hospital transfer to a comprehensive stroke center (CSC) for thrombectomy. Data regarding arterial recanalization of patients with basilar artery occlusion (BAO) during transfer are lacking.

Methods: We analyzed prospectively collected data of acute stroke patients with BAO transferred for consideration of thrombectomy to three CSCs (Rothschild Hospital, France; Montpellier Hospital, France; Stanford Hospital, USA) between 2016 and 2024, with arterial imaging at the referring hospital and on CSC arrival. Inter-hospital recanalization was assessed by comparison of the baseline and post-transfer arterial imaging and was defined as 2a-3 on the modified Thrombolysis In Cerebral Infarction (mTICI) scale. Independent predictors of inter-hospital recanalization were assessed using multivariable logistic regression analysis.

Results: Overall, 228 patients were included: median age 71 years, the National Institutes of Health Stroke Scale (NIHSS) of 14, transfer time of 3.5 h, and 39% of patients received intravenous thrombolysis (IVT) before transfer. The primary reason for withholding IVT was late presentation. Inter-hospital BAO recanalization occurred in 15% of patients. Variables independently associated with inter-hospital BAO recanalization were IVT use (adjusted odds ratio (aOR) = 24.3, 95% confidence interval (CI) = 6.9-85.5, P < 0.01), distal BAO site (aOR = 2.9, 1.0-8.5, P = 0.05), lack of diabetes (aOR = 11.4, 1.4-93.2, P = 0.02), and non-atheromatous etiology (aOR = 6.6, 1.4-31.4, P = 0.02). BAO recanalization rates ranged from 1% in non-IVT-treated patients with proximal BAO to 45% in IVT-treated patients with distal BAO. Inter-hospital recanalization was associated with an increased odds of good functional outcome (odds ratio (OR) for 3-month modified Rankin Scale (mRS) = 0-2 = 3.3, 95% CI = 1.2-8.8, P = 0.02, adjusted for age, pre-stroke mRS, baseline NIHSS, Posterior Circulation Alberta Stroke Program Early Computed Tomography Score (pc-ASPECTS), IVT use, and onset-to-imaging time).

Conclusions: BAO recanalization during inter-hospital transfer for thrombectomy occurred in 15% of patients and was associated with a favorable 3-month outcome. IVT use in the referring center was the primary modifiable factor associated with recanalization, yet its use remains low. Expanding IVT indications in primary stroke centers and developing new therapies that increase recanalization may improve outcomes.