To determine if the RACE scale is a valid pre-hospital stroke assessment for identifying Large Vessel Occlusion (LVO) in Upstate South Carolina.

In Spain, a pre-hospital stroke assessment known as the Rapid Arterial oCclusion Evaluation (RACE) scale accurately identified acute ischemic stroke patients with large vessel occlusion (LVO). The RACE scale assigns patients a score of 1-9, with scores of ≥5 suggestive of LVO. Despite the implementation of the RACE scale across United States (US) Emergency Medical Services (EMS) agencies, only few US-based studies have re-validated findings from Spain. Given the regional differences in EMS stroke protocol and patient demographics, it is unclear if the RACE scale can accurately identify LVO in all locations.

Stroke alerts with a documented RACE scale presenting to Prisma Health Greenville Memorial Hospital between January 1st, 2020-March 31st, 2020, were collected (n=126). The sensitivity and specificity for LVO detection were calculated for RACE scores ≥1- 9. Occlusion of the terminal intracranial carotid artery, middle cerebral artery (MCA) M1 segment, basilar artery, or tandem occlusion were used to define LVO. A sub-analysis expanding the definition of LVO to include occlusion of the MCA M2 segment was also conducted. 

A RACE score of ≥5 had a sensitivity of 0.71 and a specificity of 0.65. When including MCA M2 occlusion, a RACE score of ≥5 had a sensitivity of 0.73 and specificity of 0.67.

The RACE scale is a useful pre-hospital tool to identify acute ischemic stroke patients with large vessel occlusion. However, these results indicate a lower sensitivity at a RACE score of ≥5 than published in Spain. Expanding the definition of LVO to include MCA M2 occlusion may increase the sensitivity and specificity of the RACE scale. The findings from this ongoing study will be used to explore suggestions to improve this tool in the US.