Background There is substantial interest in adding endovascular stroke therapy (EST) capabilities in community hospitals. Here, we assess the effect of transitioning to an EST-performing hospital (EPH) on acute ischemic stroke (AIS) admissions in a large hospital system including academic and community hospitals.

Methods From our prospectively collected multi-institutional registry, we collected data on AIS admissions at 10 hospitals in the greater Houston area from January 2014 to December 2022: one longstanding EPH (group A), three community hospitals that transitioned to EPHs in November 2017 (group B), and six community non-EPHs that remained non-EPH (group C). Primary outcomes were trends in total AIS admissions, large vessel occlusion (LVO) and non-LVO AIS, and tissue plasminogen activator (tPA) and EST use.

Results Among 20 317 AIS admissions, median age was 67 (IQR 57–77) years, 52.4% were male, and median National Institutes of Health Stroke Scale (NIHSS) was 4 (IQR 1–10). During the first 12 months after EPH transition, AIS admissions increased by 1.9% per month for group B, with non-LVO stroke increasing by 4.2% per month (P<0.001). A significant change occurred for group A at the transition point for all outcomes with decreasing rates in admissions for AIS, non-LVO AIS and LVO AIS, and decreasing rates of EST and tPA treatments (P<0.001).

Conclusion Upgrading to EPH status was associated with a 2% per month increase in AIS admissions during the first year post-transition for the upgrading hospitals, but decreasing volumes and treatments at the established EPH. These findings quantify the impact on AIS admissions in hospital systems with increasing EST access in community hospitals.