The Impact of Weather and Mode of Transport on Outcomes of Patients With Acute Ischemic Stroke Undergoing Mechanical Thrombectomy

Abstract

BACKGROUND: Efficient transfer to mechanical thrombectomy (MT)–capable centers is essential for patients with stroke. Weather may influence stroke risk, transportation, and outcomes. OBJECTIVE: To investigate how weather affects stroke patient transfer and outcomes after MT. METHODS: We retrospectively collected data for patients with stroke transferred from spoke to our hub hospital to undergo MT between 2017 and 2021. We examined associations between weather, transportation, and patient outcomes. RESULTS: We included 543 patients with a mean age of 71.7 years. The median National Institutes of Health Stroke Score increased from 14 to 15 after transportation. The median modified Rankin Scale was 4 at discharge and 90 days, and 3 at the final follow-up (mean 91.7 days). Higher daily temperatures were associated with good outcome, whereas daily drizzle was associated with poor outcome. More patients were transferred by air when visibility was better, and by ground during heavier precipitation, higher humidity, rain, mist, and daily drizzle, fog, and thunder. Patient outcomes were not associated with transportation mode. Among the independent predictors of good outcome, none was a weather variable. Lower hourly relative humidity (P = .003) and longer road distance (P < .001) were independent predictors of using air transportation, among others. CONCLUSION: During transportation, higher temperature was associated with good outcome, whereas daily drizzle was associated with poor outcome after MT. Although weather was associated with transportation mode, no differences in outcomes were found between transportation modes. Further studies are needed to modify transfer protocols, especially during cold and rainy days, and potentially improve outcomes.