Stroke Scales for Large Vessel Occlusion in the Prehospital Emergency Setting: A Systematic Review and Meta-Analysis

Acute ischemic stroke due to large vessel occlusion (LVO) is life threatening. Endovascular therapy has improved outcomes, but adoption of prehospital LVO screening tools by emergency medical services varies, and evidence on diagnostic accuracy and utility remains limited. We aimed to evaluate the accuracy and clinical utility of prehospital LVO screening scales applied by emergency medical services.

We conducted a systematic review and meta-analysis of prospective or retrospective cohorts and randomized trials with sufficient data to construct 2×2 tables. Cochrane Central Register of Controlled Trials, MEDLINE, and Ichushi Web (Japan Medical Abstracts Society database) were searched for English and Japanese articles from October 2016 to July 2024. Two reviewers independently performed study selection, data extraction, and quality assessment using Quality Assessment of Diagnostic Accuracy Studies-2. Sensitivity and specificity were pooled using a bivariate random-effects model. Certainty of evidence was assessed with Grading of Recommendations Assessment, Development, and Evaluation, and decision curve analysis was applied at assumed LVO prevalences (5%, 10%, 20%).

Forty-three studies met inclusion criteria, and meta-analyses included 8 tools. The Rapid Arterial Occlusion Evaluation score (≥5) showed pooled sensitivity of 0.75 (95% CI, 0.68-0.81) and specificity of 0.76 (95% CI, 0.68-0.84). Field Assessment Stroke Triage for Emergency Destination (≥4) demonstrated sensitivity of 0.71 (95% CI, 0.61-0.78) and specificity of 0.75 (95% CI, 0.64-0.83). Both tools had moderate certainty of evidence, and decision curve analysis showed greater net benefit for Rapid Arterial Occlusion Evaluation and Field Assessment Stroke Triage for Emergency Destination across prevalence scenarios.

Rapid Arterial Occlusion Evaluation and Field Assessment Stroke Triage for Emergency Destination provide moderate diagnostic accuracy and clinical utility for prehospital triage of LVO stroke, supporting their integration into emergency medical services protocols and need for further validation.