Abstract WP50: Potential Impact of Triage Using Non-Contrast Head CT and Stroke Severity on a Regional Stroke System of Care: A Population-Based Study

Abstract

Background and Purpose: Acute ischemic stroke (AIS) patients may benefit from endovascular therapy (EVT) up to 24 hours since last known normal (LKN). Advanced imaging, including CT or MR angiography and perfusion studies, is required for patient selection. Large non-thrombectomy centers may be able to obtain and interpret these images quickly, but smaller hospitals may not have sufficient real-time CT technician and radiology support. We estimated transfer rates using non-contrast head CT and stroke severity to select patients to be transferred to larger centers for evaluation. Methods: We identified all AIS among residents of the Greater Cincinnati/Northern Kentucky Stroke Study region in 2010 comprising approximately 1.3 million people. Study nurses abstracted relevant information from the medical record, including times of symptom onset, LKN, and ED arrival, and all cases were verified by study physicians. Only cases age ≥18 with baseline mRS 0-2 that presented to an ED were included. Among cases that presented between 6 and 24 hours from LKN, those without evidence of acute infarct on head CT and with initial NIHSS ≥6 or ≥10 were identified. Results: Of 1359 AIS cases at local EDs, 448 (33.0%) presented between 6 and 24 hours, of which s383 (85.5%) showed no evidence of acute infarct on CT. Of cases with no acute infarct on CT, 89/383 (23.2%) had NIHSS ≥6, of which 66 (74.2%) initially presented to a hospital without thrombectomy capabilities; and 51/383 (13.3%) had NIHSS ≥10, of which 40 (78.4%) presented to a non-thrombectomy hospital. Conclusions: From 6 to 24 hours after stroke onset within our population, 40-66 AIS patients annually (0.8-1.3/week, or 3-5 patients per 100,000 persons per year) may present to non-thrombectomy hospitals and need to be transferred using non-contrast CT and stroke severity as screening tools. Such an approach may sufficiently mitigate the impact of delays in treatment on outcomes, without overburdening the referring nor accepting hospitals.