The RACE Scale for Large Vessel Stroke Diversion to a Comprehensive Stroke Center by Helicopter Air Ambulance: A Retrospective Cohort Study

Objective

Acute ischemic stroke caused by large vessel occlusion (LVO) occurs frequently and benefits from endovascular therapies available at comprehensive stroke centers (CSCs). Prehospital stroke severity tools have been devised to detect LVO. The goal of this study was to assess the value of the Rapid Arterial Occlusion Evaluation (RACE) score in helicopter air ambulance (HAA) activation.

Methods

A retrospective assessment of RACE scales > 4 performed by prehospital providers was used in order to activate HAAs. Descriptive statistics were obtained for patients transported, with the primary goal of determining the positive predictive values of the RACE scale for LVO occlusions. The secondary outcomes assessed if patients without LVO had other conditions requiring a CSC.

Results

Data from 136 subjects were analyzed; 53 (39.0%) were true LVO cases as defined by computed tomographic imaging, computed tomography angiographic imaging, or magnetic resonance imaging. Mechanical thrombectomy occurred in 30 cases (22.1%), with 63 (46.4%) requiring a neurologic intervention. There were 83 (61%) false positives (no LVO on imaging). Of these false positives, 28 (20.6%) were non-LVO strokes, 22 (16.1%) were intracranial hemorrhages, and 8 (5.9%) had neurologic conditions requiring CSC care.

Conclusion

A RACE scale > 4 is an effective triage tool that delivers potential thrombectomy candidates to CSCs. When there is a false positive, the majority of patients require CSC care and benefit from direct transport from the scene.