Abstract TP262: Pre-Hospital VAN Large Vessel Occlusion Screening Tool Predicts Larger Intracerebral Hemorrhage

Abstract

Introduction: An EMS validation study in San Antonio, Texas previously evaluated the Vision Aphasia Neglect (VAN) screen to identify large vessel occlusion (LVO) in the prehospital setting. Because it may be used in the field to bypass hospitals for higher level care, VAN’s performance with stroke mimics, specifically intracerebral hemorrhage (ICH), is important in stroke systems of care. The goal of this study was to determine if a positive VAN assessment correlated with larger ICH. Methods: Paramedics from two San Antonio EMS agencies documented a VAN assessment from June 2017 to April 2019 for all EMS stroke alerts less than 6 hours from last known well. The prehospital VAN score, emergency department advanced neuroimaging interpretation, and hospital discharge diagnosis were collected from three comprehensive stroke centers. Stroke mimics and hemorrhages were included. ICH volume, location, and presence of intraventricular hemorrhage (IVH) were recorded. ICH volume and location were dichotomized by the median value and infratentorial versus supratentorial, respectively. Descriptive statistics were used for continuous data, and categorical data was analyzed by Fisher’s exact test. Results: VAN scores were recorded for 215 EMS activated stroke alerts, of which 131 (60.9%) were VAN positive and 23 (10.7%) were ICH. All were hypertensive etiologies except one arteriovenous malformation related hemorrhage. ICH mean and median values were 15.3 ml and 10.3 ml (range 0.3 - 51 ml), respectively. Of the 23 ICH cases, IVH was present in 7 (30%), and infratentorial location was noted in 4 (17%). Fisher’s exact test for VAN and ICH (categorized as ≥ or < median volume) was significant (0.027, p<0.05). However, VAN versus both ICH location and presence of IVH was non-significant. Conclusion: In this prospective EMS validation study, a pre-hospital VAN positive assessment predicted larger ICH volumes. Although VAN was designed to identify LVO, pre-hospital triage of ICH is an additional benefit of this screening tool. A false positive VAN assessment for LVO may signify a larger ICH, which is often transferred to higher level centers as standard of care. Thus, VAN perform well for both ischemic and hemorrhagic hospital bypass protocols.