Comparing validated stroke screening scales for identifying large and medium vessel occlusions: a prospective observational cohort study.

Background: Rapid prehospital identification of acute ischemic stroke secondary to large vessel occlusions (AIS-LVO) has been successful in triaging patients, but the use of stroke screening scales often varies. This study aims to compare different stroke screening scales for the detection of anterior and posterior circulation AIS-LVO and AIS secondary to medium vessel occlusions (AIS-MeVO).

Methods: We prospectively analyzed stroke alert activations at a comprehensive stroke center between August 1, 2022 and December 31, 2023. We applied eight stroke screening scales (BE-FAST, LAMS, PASS, FAST-ED, EMS RACE, 3-ISS, VAN, and NIHSS) to each stroke alert in the emergency department (ED) and inpatient wards. The final diagnosis was classified as AIS-LVO or AIS-MeVO, AIS without LVO or MeVO, intracranial hemorrhage, transient ischemic attack, or stroke mimic.

Results: A total of 198 patients were analyzed. The mean age was 63.9±15.3 years, 62.1% were female (n=123), and 84.3% were African American/black subjects (n=167). The LAMS scale had a strong performance (area under the curve (AUC) 0.750 (95% CI 0.668 to 0.831)), closely followed by the FAST-ED (AUC 0.736 (95% CI 0.649 to 0.822)) and the VAN (AUC 0.735 (95% CI 0.651 to 0.818)) scales. Cut-off points selected from coordinates of the receiver operating characteristic curves were 3, 3, and a positive VAN, respectively.

Conclusion: This is the first prospective cohort study to compare the performance of eight different screening scales among stroke alerts for detection of AIS-LVO and AIS-MeVO. We found LAMS to be the most discriminative tool, followed by FAST-ED and VAN. However, the findings were non-significant, reinforcing existing retrospective literature that these validated screening scales perform similarly and one is not superior.