LVO TRUST EMS – Large vessel occlusion triage and routing utilized for long-distance stroke transports by emergency medical services

Abstract

Background and purpose

Endovascular treatment (EVT) is the most effective therapy in acute ischemic stroke (AIS) with large vessel occlusion (LVO) but its practice is limited to Comprehensive Stroke Centers (CSC). Previous studies have suggested that trained Emergency Medical Services (EMS) professionals can successfully detect LVO cases using a validated screening tool. We aimed to assess the diagnostic accuracy of trained community-based EMS.

Methods

This is a retrospective cohort study from 01/01/2018–12/31/2022 of patients with suspected stroke transported by EMS providers from 14 community agencies in Southeastern Massachusetts. When stroke was suspected, EMS providers applied the Field Assessment Stroke Triage for Emergency Destination (FAST-ED) score to assess severity. Bypass of local community hospitals for direct transport to CSC was generally considered for patients with FAST-ED ≥ 4 and approval of the Region V EMS Medical Director.

Results

Among the 166 patients triaged for direct transport to the CSC, 57.2 % were diagnosed with AIS, of whom 56.8 % had LVO, and 64.8 % of those received EVT. There was a higher proportion of AIS or intracranial hemorrhage (ICH) in cases with higher FAST-ED scores. Only 23.5 % of the cases were diagnosed with stroke mimics, associated with lower FAST-ED scores. In total, 36.9 % of patients with AIS received EVT: thrombectomy with standard window tPA (21.1 %) or late-presenter window tPA (LKW ≥ 4.5 h, 1.1 %), and without tPA (14.7 %).

Conclusions

A diverse group of community-based EMS services in Southeastern Massachusetts using a prehospital tool can identify patients with severe stroke, i.e. AIS due to LVO or ICH, with acceptable diagnostic accuracy.