Abstract WP37: Prehospital Stroke Scales Outperform National Institutes Of Health Stroke Scale In Predicting Large Vessel Occlusion In A Large Telestroke Network

Abstract

Introduction: Prehospital telestroke is increasingly utilized in mobile stroke units and telemedicine-enabled ambulances for acute ischemic stroke (AIS). While the NIHSS remains the standard for telestroke assessment, simpler scales have been validated to help paramedics recognize large vessel occlusion (LVO) strokes but have not been evaluated in a traditional telestroke network. We aimed to determine the accuracy of common LVO scales in a large academic telestroke practice. Methods: This retrospective study included all telestroke consults performed in a large academic telestroke network from 2019 to 2020. Patients were excluded if no NIHSS or vessel imaging was performed. We recorded presenting NIHSS, site of vessel occlusion, and discharge diagnosis. LVO was defined as an acute occlusion of the internal carotid artery and/or M1 middle cerebral artery. The NIHSS was used to calculate 7 LVO scales (RACE, C-STAT, FAST-ED, 3I-SS, PASS, VAN, and G-FAST). Diagnostic performance was assessed by calculating sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy using the established thresholds of each scale. These results were compared to NIHSS at thresholds of 6, 8, and 10. Area under curve (AUC) was calculated using c-statistics by treating scales as continuous variables. Results: A total of 625 patients were included, 373/625 (59.7%) of which were diagnosed with AIS at discharge. LVO was identified in 78/625 (12.5%) patients. VAN was the most sensitive prehospital stroke scale (83.3%), whereas 3I-SS ≥ 4 was the most specific (95.2%). Both the RACE and FAST-ED scales demonstrated superior accuracy and AUC compared to the NIHSS (Table 1). Conclusions: To our knowledge, this is the first study assessing LVO scale accuracy in a large telestroke network. As use of prehospital telestroke grows, this study highlights several scales that may allow for faster prehospital triage decisions without sacrificing accuracy.