Limited Reperfusion Time Benefit of Emergency Medical Service Transportation for Acute Myocardial Infarction in an Urban Area

Abstract Background: ST-segment elevation myocardial infarction (STEMI) is a critical condition that typically presents in the emergency department (ED) and expeditious reperfusion therapy is key to better outcomes. This study aimed to evaluate the reperfusion time benefit and role of Emergency Medical Service (EMS) activation in patients with STEMI using the model of the county-based EMS system in Taiwan. Methods: This retrospective cohort study was conducted over the four-year period at an urban, tertiary care teaching hospital, Taoyuan, Taiwan. A total of 236 patients admitted to the ED with a diagnosis of STEMI during the study period were enrolled, of whom 174 (73.7%) arrived at the hospital on their own (self-transported group) and 62 (26.3%) were referred by the EMS (EMS-transported group). More patients in the EMS-transported group than self-transported group were classified as critical at triage (90.3% vs. 73.7%, p = 0.005). The mortality rates of the self-transported and EMS-transported patients were 4.6% and 11.5%, respectively (p = 0.060). In patients who survived to discharge, the median hospital LOS was 4.0 days [IQR: 3.0–5.0 days] in both groups (p = 0.545). Results: The EMS-transported group had a significantly shorter door-to-ECG time (median: 2.0 minutes vs. 3.0 minutes, p = 0.020). The median D2B time was 68.0 vs. 69.0 minutes for the EMS vs. self-transported group (p = 0.826). Less than 30% of patients (29.0% vs. 25.9%, p = 0.628) achieved the 60-minute goal. Arrival at ED during office was the only factor significantly associated with achievement of the 60-minute goal (61.9 vs. 20.2%, p < 0.001). Conclusion: EMS activation was not associated with a shorter in-hospital reperfusion time in patients with STEMI in an urban area with a short transportation time. Although they tended to have more severe disease, the EMS-transported patients had comparable clinical outcomes as the self-transported group.