Accuracy of Published Screening Tools for Large Vessel Occlusion in Patients With Suspected Acute Ischemic Stroke: A Prospective Cohort Study

To identify the most accurate screening tool for predicting a large vessel occlusion in patients with a suspected acute ischemic stroke. Between January 2022 and April 2023, adult patients with a suspected acute ischemic stroke for whom an emergency physician activated the stroke code (indicating potential eligibility for thrombolysis and/or thrombectomy) at the emergency department (ED) of l'Hôpital de l'Enfant-Jésus-CHU de Québec, a tertiary care center for neurologic diseases, were prospectively included. Demographic data and variables included in 8 screening tools were collected by the emergency physician prior to the head computed tomography using a standardized data collection form. The performance of each tool to identify patients with a large vessel occlusion was assessed using the accuracy with 95% confidence intervals (CIs) and the McNemar test was used to compare the performance of the tools. A total of 390 patients were included in the study (mean age: 72.3 years; men: 48.2%). Acute ischemic strokes was the final diagnosis in 259 patients (66.4%) of which 111 (28.5%) had a large vessel occlusion. The accuracy of Field Assessment Stroke Triage for Emergency Destination (FAST-ED) was 0.76 (95% CI 0.72 to 0.81), which was not significantly different from that of Rapid Arterial Occlusion Evaluation Scale (0.75, 95% CI 0.71 to 0.80), Los Angeles Motor Scale (0.75, 95% CI 0.71 to 0.79), or Large ARtery Intracranial Occlusion stroke scale (0.72, 95% CI 0.68 to 0.77). However, it was significantly higher than the accuracy of Conveniently-Grasped FAST, Ambulance Clinical Triage-FAST, Vision, Aphasia, Neglect assessment, and Face-Arm-Speech-Time plus severe arm or leg motor deficit. Cincinnati Prehospital Stroke Scale, when performed by either the emergency physicians or paramedics, demonstrated poor accuracy, with values of 0.34 (95% CI 0.29 to 0.39) and 0.37 (95% CI 0.32 to 0.34), respectively. This study provides valuable insights into the accuracy of various large vessel occlusion screening tools for patients in our ED setting with FAST-ED, Rapid Arterial Occlusion Evaluation Scale, and Los Angeles Motor Scale showing the highest levels of accuracy. These findings will contribute to the development of evidence-based care pathways for improving stroke diagnosis and management.