Benefits of First Pass Recanalization in Basilar Strokes Based on Initial Clinical Severity

Purpose: Randomized trials demonstrating the benefits of thrombectomy for basilar artery occlusions have enrolled an insufficient number of patients with a National Institutes for Health Stroke Scale (NIHSS) score < 10 and shown discrepant results for patients with an NIHSS > 20. Achieving a first pass recanalization (FPR) improves clinical outcomes in stroke. We aimed to evaluate the effect of the FPR on outcomes among basilar artery occlusion patients, characterized by prethrombectomy initial NIHSS score.

Methods: We retrospectively analyzed the Endovascular Treatment in Ischemic Stroke (ETIS) registry of 279 basilar artery occlusion patients treated with thrombectomy from 6 participating centers. We compared the 90-day clinical outcomes of achieving a FPR versus no FPR, categorized by initial clinical severity: mild (NIHSS < 10), moderate (NIHSS 10-20) and severe (NIHSS > 20). We used Poisson regression with robust error variance to determine the effect of the NIHSS score on the association between FPR and outcomes.

Results: The FPR patients with NIHSS < 10 or NIHSS 10-20 were more likely to have a favorable clinical outcome (modified Rankin scale, mRS 0-3) than non-FPR patients (relative risk, RR = 1.32, 95% confidence interval, CI: 1.04, 1.66, p-value = 0.0213, and RR = 1.79, 95% CI: 1.26, 2.53, p-value = 0.0011, respectively). A similar benefit was not found in patients with severe symptoms. We found a significantly lower risk of poor clinical outcome (mRS 4-6) in FPR patients with NIHSS 10-20, but not among patients with an NIHSS > 20.

Conclusion: Achieving a FPR in basilar artery occlusion patients with mild (NIHSS < 10) or moderate (NIHSS 10-20) symptoms is associated with better clinical outcomes, but not in patients with severe symptoms. These results support the importance of further clinical trials on the benefits of thrombectomy in severe strokes.