Abstract Body: Background: Prior studies reported only half of stroke patients arrived at emergency departments (ED) via emergency medical services (EMS). Some studies found EMS arrival to be associated with more rapid evaluation and treatment which have been shown to be associated with better outcomes. We sought to explore ED modes of arrival for potential acute stroke patients in two large racial-ethnically diverse regional cohorts in California.

Methods: Kaiser Permanente Northern California (KPNC) consists of 21 certified stroke centers, and Kaiser Permanente Southern California (KPSC) have 15 certified centers. Both regions have standardized Telestroke programs for all stroke centers to include video evaluation by a teleneurologist. From 1/1/2016 to 12/31/2022, the KPNC study cohort included all non-cancelled stroke alerts who were potential candidates for further workup for acute ischemic stroke treatment. Non-cancelled group was approximately 45% of the total stroke alert volume in the KPNC region. During the same period, KPSC study cohort included all stroke alerts who were evaluated by Telestroke for possible acute stroke. KPSC did not use a cancel-versus-non-cancel system. Assessment included demographics, ED mode of arrival, and neighborhood deprivation index (NDI).

Results: During the study period, there were 17,437 patients from KPNC and 41,466 patients from KPSC yielding a combined total of 58,903 adults evaluated by Telestroke neurologists for possible acute stroke at 36 stroke centers in California. Overall, 31,533 (53.5%) arrived via walk-in rather than EMS. However, in Southern CA, patients were more likely on average, to arrive as walk-in (67.7%) compared to Northern CA (19.8%). Range of walk-in for KPNC facilities was 11% to 38.5%, and 34% to 86.1% for KPSC centers [Figure]. Patients who presented as walk-in tended to be younger and more Hispanic. Those from more impoverished communities presented via EMS more often than via walk-in [Table].

Conclusions: In our combined cohort, there were several differences between walk-in patients and those who arrived via EMS. There was notable variation in ED arrival mode by facility and stark contrast between the two regions in California. Further research is needed to understand these differences and whether they are associated with outcomes, and to identify potential targets for future interventions to improve acute stroke care delivery for walk-in patients.