Including isolated aphasia improves sensitivity and negative predicative value for large vessel occlusion screening

Abstract

BackgroundLarge Vessel Occlusion (LVO) screening tools provide objective assessments to guide diagnostic decisions during acute stroke activations. The Stroke VAN screening tool includes weakness, vision, aphasia, and neglect; however, only screens positive if weakness is present regardless of presence of other symptoms including isolated aphasia. The purpose of this project was to evaluate wAve, a modified Stroke VAN screening tool. WAve includes components of VAN with emphasis on isolated aphasia. MethodsWe conducted a retrospective cohort study on 376 persons who presented with stroke symptoms within 24 h of last known well (LKW) to the Emergency Department of an urban comprehensive stroke center in north central Texas between July 2019 and January 2020. Comparison of VAN and wAve predictive values was calculated using Chi square analysis. Sensitivity and specificity was checked by using MedCalc software. Data from the electronic medical record was obtained for analysis including a documented wAve score and a calculated VAN score. Results of CT angiogram diagnostic testing was used to determine congruence of screening results with evidence of LVO. Power analysis described by Hajian- Tilaki was used to estimate study size. ResultsResults included 192 positive wAve screens and 184 negative wAve screens compared to 152 positive VAN screens and 224 negative VAN screens. The sensitivities for wAve and VAN were 89 % and 80 % respectively. Negative predictive values for wAve and VAN were 97 % and 95 % respectively. In isolated aphasic person, one of eight presented with a LVO and received intervention. ConclusionThe team discovered more LVOs were identified with wAve than VAN in persons exhibiting isolated aphasia symptoms. Larger studies are needed to understand the role isolated aphasia plays in LVO detection.