Abstract DP106: Vision, Aphasia, Neglect Tool for Large Vessel Occlusion in the Prehospital Setting

Background: The Vision, Aphasia, Neglect (VAN) screening tool is a rapid, prehospital assessment to identify large vessel occlusions (LVOs) in acute ischemic stroke patients. Other studies that looked at prehospital utilization of the VAN assessment reported sensitivity and specificity of 81%/38% and 84%/68%, respectively. In particular, one study compared other scales: Rapid Arterial Occlusion Evaluation (84%/60%), Cincinnati Stroke Triage Assessment Tool (71%/67%), and Los Angeles Motor Scale (76%/65%). While prior studies have evaluated its utility, further validation in real-world prehospital settings is warranted. In 2020, our Mobile Stroke Unit (MSU) implemented the VAN to rapidly and efficiently identify a potential LVO. Purpose: The purpose was to assess the sensitivity and specificity of the VAN assessment through a chart review of patients transported from May 2020 - June 2025 on a MSU. Methods: We analyzed VAN assessment results and confirmed LVO diagnoses based on imaging. Due to limitations in obtaining final stroke diagnosis from hospitals outside our network, 190 out of the 334 total cases were included. Patients were categorized based on VAN positive/negative assessment and the presence/absence of LVO. We also examined VAN outcomes in hemorrhagic stroke cases and noted specific areas where the VAN may have reduced accuracy. Results: Of the 190 patients: 111 were VAN negative/LVO negative, 46 VAN positive/LVO negative, 5 VAN negative/LVO positive, and 28 VAN positive/LVO positive. This yielded a sensitivity of 85% and specificity of 71%, with a PPV of 38% and NPV of 96%. Additionally, 12 patients with hemorrhagic strokes were evaluated, 6 were VAN positive and 6 were VAN negative. This indicates a potential overlap in findings with some limitations noted in the carotid terminus and distal middle cerebral artery M2 segment occlusions. Conclusions: To our knowledge, this is the first analysis looking at utilization of VAN assessments on Mobile Stroke Units. In conclusion, our data suggests that the VAN tool is a valuable and effective method for prehospital LVO detection on a MSU, performing with greater accuracy than previously reported in similar EMS-based studies. While not without limitations, the VAN remains a strong candidate for rapid field screening, supporting its continued use and further prospective evaluation.