Prehospital Stroke Scales Outperform National Institutes of Health Stroke Scale in Predicting Large Vessel Occlusion in a Large Academic Telestroke Network

Abstract

AbstractBackgroundWith growing emphasis on prehospital identification of large vessel occlusion (LVO), some experts have advocated for prehospital involvement of vascular neurologists. Prehospital telestroke may improve triage and in-hospital treatment, but the accuracy of prehospital LVO scales in telestroke has not been investigated.MethodsWe performed a retrospective study of telestroke consultations in a large academic telestroke network from 2019 to 2020. We assessed performance of 7 LVO scales using the NIHSS score at presentation (RACE, C-STAT, FAST-ED, 3I-SS, PASS, VAN, and G-FAST). We performed two analyses using different LVO definitions: (1) anterior LVO including occlusion of the internal carotid (ICA), middle cerebral (M1 or M2), or anterior cerebral (A1 or A2) arteries; and (2) any LVO including occlusion sites above plus basilar artery or posterior cerebral artery (P1 or P2). Diagnostic performance was assessed via sensitivity, specificity, negative predictive value, positive predictive value, positive likelihood ratio, negative likelihood ratio, and accuracy using 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.ResultsA total of 625 patients were included; 111 (17.8%) patients had an anterior LVO, 118 (18.9%) patients had any LVO, and 182 (29.1%) patients had stroke mimic diagnosis. Mean age (SD) was 67.9 (15.9), 48.3% were female, and 93.4% were white. Mean NIHSS (SD) was 14.9 (8.4) for patients with anterior LVO, 4.7 (5.0) for patients with non-LVO ischemic stroke, and 4.4 (5.8) for stroke mimic (p<0.001). Compared to the NIHSS, FAST-ED and RACE scales demonstrated higher accuracy and AUC for LVO detection.ConclusionsBoth the FAST-ED and RACE scales outperformed the NIHSS for LVO detection in patients evaluated by telestroke. These scales may be valid alternatives to the NIHSS examination in this setting.