Abstract T MP59: Texas Stroke Intervention Pre-Hospital Stroke Severity Scale (aka LEGS score): A Triaging Tool for Interventional Stroke Therapy

Abstract

Introduction: A pre-hospital stroke severity scale that correlates well with an NIHSS of 10 or greater as well as with large vessel occlusions, but is easier and faster to perform than full NIHSS, would be a very useful triaging tool to emergency medical services (EMS). The LEGS score (Lower extremity strength, Eyes/visual fields, Gaze deviation, Speech difficulty) is a 16-point pre-hospital stroke severity scale that is a shortened NIHSS-5. Hypothesis: We assessed the hypothesis that the LEGS score was a useful pre-hospital stroke severity scoring system to identify large vessel acute ischemic strokes. Methods: The LEGS score (0-16) and NIHSS (0-42) were performed in the emergency department over a 6-month period. We retrospectively reviewed those charts for correlation to an NIHSS of 10 or greater and evidence of large-vessel occlusion on either CT or MR Angiography within 48 hours of last known normal. Results: A total of 181 consecutive ischemic stroke patients were evaluated. LEGS score 4 or greater was a good predictor of an NIHSS of 10 or greater (59/181; positive predictive value 92%; and specificity 95%) and false positives noted was 5/181. LEGS score of less than 4 was a good predictor of an NIHSS of less than 10 (108/181; negative predictive value 91%; and sensitivity 95%) and false negatives noted was 10/181. Of those patients 155 underwent intracranial vascular imaging. LEGS score of less than 4 was a good test to rule-out large vessel occlusion (negative predictive value of 86%; 89/103), but had modest sensitivity (69%; 31/45) and positive predictive value (60%; 31/52). The LEGS score of 4 or greater, however, was fairly specific for determining large-vessel occlusions at 81% (89/110). Conclusions: LEGS score of 4 or greater has good correlation with an NIHSS of 10 or greater as well as modest correlation with large vessel occlusion on CT or MR Angiography. This shortened NIHSS-5 may be a useful pre-hospital indicator of patients who may benefit from endovascular intervention.