Abstract TMP14: Population-Based Intracranial Vascular Imaging for Acute Ischemic Stroke is Suboptimal

Abstract

Introduction: Endovascular thrombectomy (EVT) is the standard of care for patients with ischemic stroke and large vessel occlusion (LVO). Intracranial vascular imaging is required to determine the presence of an LVO. Although patients can be eligible for EVT up to 24h after last seen normal (LSN), current imaging protocols focus on the first 6h from LSN. We evaluated the use of intracranial vascular imaging in patients with ischemic stroke as a function of time since LSN in Ontario, Canada. Methods: We analyzed data from the Ontario Stroke Registry which performed primary data collection evaluating care and outcomes in 13,828 patients hospitalized with stroke across Ontario in the fiscal year 2019/20. This sampling strategy included 93.3% of all strokes in a province of 14.5 million residents. We used modified Poisson regression models to evaluate the association between time from LSN to first hospital presentation (<6h, 6-12h, 12-24h) and receipt of intracranial vascular imaging with computed tomographic angiography or magnetic resonance angiography. We adjusted for baseline differences and estimated the adjusted relative risk (aRR) of imaging. Results: Data collection is >75% completed and full results will be presented at the ISC. Of 8,482 patients with ischemic stroke, 6,345 (74.8%) presented within 24h of LSN (n=3,811 <6h; n=1,368 6-12h; n=1,166 12-24h). Median age was 76 years (IQR 66-85) and 3,002 (47.3%) were women. Overall, 5,196 (81.9%) patients had intracranial vascular imaging, but compared to those within 6h of LSN (86.8% imaged), patients presenting later were less likely to receive vascular imaging (77.2% for 6-12h, aRR 0.91 95%CI [0.88, 0.94] and 71.4% for 12-24h, aRR 0.85 95%CI [0.82, 0.88]). Of those imaged, 895 (17.2%) had an LVO (18.5% <6h; 16.4% 6-12h, 13.3% 12-24h, p<0.01) and 492 (55.0%) patients with LVO underwent EVT. Conclusions: On a population basis, over 80% of patients with ischemic stroke had intracranial vascular imaging, but gaps in care exist for those presenting in the later time window. Up to one in three patients presenting beyond 6h from LSN did not have vascular imaging. Systems of care must be optimized to support LVO identification and EVT access in later time windows.