Abstract WP48: Air Versus Land Transfers For Endovascular Thrombectomy In A Hub-and-spoke Comprehensive Stroke Network

Abstract

Background: Endovascular thrombectomy (EVT) is only available at larger comprehensive stroke centers, with inter-hospital transfer by road or air ambulance required for patients who first present to a primary stroke centre. We aimed to evaluate if there were differences in outcomes in patients transferred for EVT via air. Methods: The setting is a hub-and-spoke model, with one EVT center which receives patients from three metropolitan and 12 more distant regional primary stroke centers. Consecutive EVT patients were identified from a mandatory registry, which includes data on mode of transfer to the EVT center. The primary outcome was 90-day functional independence (modified Rankin scale ≤2). Secondary outcomes included successful recanalization (Thrombolysis In Cerebral Infarction score ≥2b), early neurological improvement (National Institutes of Health Stroke Scale (NIHSS) reduction by ≥8 points or a reduction to ≤1 at 24 hours), symptomatic intracranial hemorrhage, and 90-day mortality. Results: 1102 patients (622 (56%) men, median [interquartile range, IQR] age 69 [58-78], 966 (88%) anterior circulation strokes, median [IQR] baseline NIHSS 16 [11-20]) were identified. 801 (73%) patients presented to the EVT center by road and 301 (27%) regional patients transferred by air. The mean (standard deviation, SD) distance travelled to the EVT center was 9.6 (1.2) miles by road and 106.8 (50.9) miles by air. The two groups were well-matched at baseline except a higher thrombolysis rate in the air transfer group (53% vs 45%, p =0.022). Patients transferred by air had longer last-known-well to EVT groin puncture times (median [IQR] 365 [294-539] vs 225 [170-355] minutes, p <0.001), however there were no differences in the proportion of patients with 90-day functional independence (151 (50%) by air vs 427 (53%); p =0.388) or 90-day mortality (44 (15%) by air vs 122 (15%); p =0.874), or any of the other secondary outcomes. Conclusions: In this hub-and-spoke model, patients transferred for EVT from regional centers by air had similar outcomes at 90-day to those presenting to a metropolitan center, despite the longer transfer times. Comprehensive stroke centers should not be discouraged from considering patients from more distant centers who require air transfer.