Räty, SiljaStrambo, DavideRäty, SiljaGomez-Exposito, AlexandraMarto, João PedroStrambo, DavideRamos, João NunoKrebs, StefanVirtanen, PekkaMarto, João PedroRitvonen, JuhaniAbdalkader, MohamadRamos, João NunoKlein, PiersSairanen, TiinaSykora, MarekVirtanen, PekkaLindsberg, Perttu J.Poli, SvenMichel, PatrikNguyen, Thanh N.Klein, PiersStrbian, DanielSairanen, TiinaSykora, MarekLindsberg, PerttuPoli, SvenMichel, PatrikNguyen, Thanh2025-06-252025-06-252025-101747-4930PURE: 119468354PURE UUID: 3faf471f-a5b8-46fa-b307-257d80e6e6e1Scopus: 105008080397PubMed: 40356017http://hdl.handle.net/10362/184476Funding Information: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study was supported by Helsinki University Hospital governmental subsidiary funds for clinical research (S.R., P.J.L., D.Strbian). Publisher Copyright: © 2025 World Stroke Organization.Background: Randomized controlled trials have demonstrated an improved outcome of basilar artery occlusion (BAO) with endovascular thrombectomy (EVT) compared to best medical treatment. However, a minority of the patients recruited up to 12–24 h from onset in the positive trials received intravenous thrombolysis (IVT), and a trial with a higher IVT rate did not show superiority of EVT. Thus, the efficacy and safety of EVT compared to IVT for BAO remain less clear. Aims: We aimed to compare outcomes after IVT alone to EVT with or without IVT for acute BAO. Methods: This international, observational, retrospective study included patients who received recanalization therapy for BAO at six centers between January 2010 and March 2024. The primary outcome was 3-month modified Rankin Scale (mRS) score 0–3, and secondary outcomes comprised mRS 0–2, ordinal mRS, mortality, and symptomatic intracranial hemorrhage. Outcomes after IVT versus EVT ± IVT were compared using inverse probability-weighted regression adjustment models adjusting for known predictors of outcome in BAO and baseline variables differing between the treatment groups. Interaction of the treatment group with symptom severity and onset-to-treatment time was tested. Results: Of 523 patients with BAO (median age 69, 35.2% women), 28.9% received IVT and 71.1% EVT ± IVT. The IVT-alone group had a lower baseline National Institutes of Health Stroke Scale score (median 11 vs 15) but equally extensive ischemic changes in baseline imaging. After inverse probability-weighted regression adjustment, the IVT-alone group had higher odds of mRS 0–3 (adjusted odds ratio (aOR) = 2.33 [95% confidence interval (CI) = 1.31–4.12]), mRS 0–2 (aOR = 1.93 [95% CI = 1.12–3.30]), lower median mRS (aOR = 1.81 [95% CI = 1.21–2.71]), and lower mortality (aOR = 0.53 [95% CI = 0.29–0.97]), but no difference in symptomatic intracranial hemorrhage (aOR = 0.81 [95% CI = 0.28–2.36]). No interactions for the primary outcome were found. Conclusion: In this study, patients with BAO had better outcome after IVT than EVT ± IVT independent of symptom severity and time from onset. Although the non-randomized design of the study warrants caution, the results encourage further trials comparing EVT and IVT to guide recanalization therapy in BAO patients. Data access statement: Anonymized data are available upon reasonable request to the corresponding author following the national legislation.904348engBasilar artery occlusionendovascular thrombectomyintravenous thrombolysisNeurologyClinical Neurologyjournal article10.1177/17474930251344451https://www.scopus.com/pages/publications/105008080397