English, Stephen

Introduction: Telestroke enables timely and remote evaluation of patients with acute stroke syndromes. However, stroke mimics represent more than 30% of this population. Given the resources required for management of suspected acute ischemic stroke, several scales have been developed to help identify stroke mimics. Our objective was to externally validate four mimic scales (Khan Score [KS], TeleStroke Mimic Score [TS], simplified FABS [sFABS], and FABS) in a large, academic telestroke network. Methods: This is a retrospective, IRB exempt study of all patients who presented with suspected acute stroke syndromes and underwent video evaluation between 2019-2020 at a large academic telestroke network. Detailed chart review was conducted to extract both the variables needed to apply the mimic scales the final diagnosis confirmed by final imaging and discharge diagnosis (cerebral ischemic vs stroke mimic). Overall score performance was assessed by calculating area under curve (AUC). Youden cutpoint was established for each scale and used to calculate sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy. Results: A total of 1043 patients were included in the final analysis. Final diagnosis of cerebral ischemia was made in 662/1043 patients (63.5%) and stroke mimic was diagnosed in 381/1043 patients (36.5%). To predict stroke mimic, TS had the highest AUC (68.3) and PPV (73%); KS had the highest accuracy (68.6%), sensitivity (86.6%) and NPV (61.5%); and FABS had the highest specificity (54.8%) (Table 1). Conclusions: While each scale offers unique strengths, none was able to identify stroke mimics effectively enough to confidently apply in clinical practice. There remains need for significant clinical judgment to determine the likelihood of stroke mimic at presentation.

Introduction Prehospital telestroke evaluations may improve stroke triage compared to paramedic-applied large vessel occlusion scales, but ambulance-based video National Institutes of Health Stroke Scale assessments are challenging. The accuracy of telestroke-administered large vessel occlusion scales has not been investigated, so we sought to evaluate this further. Methods This retrospective study included all in-hospital telestroke encounters in a large academic telestroke network from 2019 to 2020. We retrospectively calculated seven large vessel occlusion scales using the in-hospital telestroke National Institutes of Health Stroke Scale (Rapid Arterial oCclusion Evaluation, Cincinnati Stroke Triage Assessment Tool, Field Assessment Stroke Triage for Emergency Destination, 3-Item Stroke Scale, Prehospital Acute Stroke Severity, Vision-Aphasia-Neglect, and Gaze-Face-Arm-Speech-Time). Diagnostic performance was assessed via sensitivity, specificity, negative predictive value, positive predictive value, positive likelihood ratio, negative likelihood ratio, and accuracy using established scale thresholds. These results were compared to the National Institutes of Health Stroke Scale at thresholds of 6, 8, and 10. The area under curve was calculated using c-statistics by treating scales as continuous variables. Results A total of 625 patients were included; 111 (17.8%) patients had an anterior large vessel occlusion, 118 (18.9%) patients had any large vessel occlusion, and 182 (29.1%) patients had stroke mimic diagnosis. The mean age (SD) was 67.9 (15.9), 48.3% were female, and 93.4% were white. The Mean National Institutes of Health Stroke Scale (SD) was 14.9 (8.4) for patients with anterior large vessel occlusion, 4.7 (5.0) for patients with non-large vessel occlusion ischemic stroke, and 4.4 (5.8) for stroke mimic ( p < 0.001). Compared to the National Institutes of Health Stroke Scale, Field Assessment Stroke Triage for Emergency Destination, and Rapid Arterial oCclusion Evaluation scales demonstrated higher accuracy and area under curve for large vessel occlusion detection. Discussion Both the Field Assessment Stroke Triage for Emergency Destination and Rapid Arterial oCclusion Evaluation scales outperformed the National Institutes of Health Stroke Scale for large vessel occlusion detection in patients evaluated by in-hospital telestroke. These scales may be valid alternatives to the National Institutes of Health Stroke Scale examination in this setting.