Improving EMS Identification of Patients With Large Vessel Occlusion

Introduction: The 9- point Rapid Arterial oCclusion Evaluation (RACE) score was developed to aid emergency responders identify patients with stroke related to large vessel occlusion (LVO) for transport to a center for endovascular management. We determined whether the addition of historical features available at the time of EMS evaluation will improve the detection of LVO. Methods: We conducted a retrospective medical record review of patients admitted in 2014 to a Comprehensive Stroke Center with a presumed cardioembolic ischemic stroke based on ASCO criteria. Occlusion of a relevant proximal vessel was determined by initial CT or MR angiography. Candidate variables were selected based on univariable comparisons between those with and without an occlusion (p<0.1) and their independent association with LVO identified with multiple logistic regression with backwards selection. Results: The sample included 100 patients with LVO and 128 without an occlusion. RACE score (mean 4.64±0.31 vs 2.20±0.21, p=0.007), known atrial fibrillation (AF, 40% vs 23%, p=0.005), no anticoagulation (92% vs 83%, p=0.048), higher blood glucose (mean 150±7 vs 132±5 mg/dL, p=0.001) a history of hypertension (89% vs 81%, p=0.085) or diabetes (47% vs 34%, p=0.053) were associated with LVO in univariable analyses. The risk was particularly high in those with AF who were not anticoagulated (44% vs 16%, p<0.001). In the multiple logistic regression analysis, RACE score (OR 1.30, 95% CI 1.17-1.45), AF (OR 3.25, 95% CI 1.62-6.54), diabetes (OR 2.03, 95% CI 1.08-3.82), and anticoagulant therapy (OR 0.17, 95% CI 0.06-0.48) were independently associated with LVO. Conclusions: The inclusion of selected historical features (AF, diabetes, anticoagulation status) will improve the accuracy of the RACE score in the pre-hospital identification of stroke due to LVO who might benefit from acute thrombectomy.