Developments in pre-hospital patient transport in ST-elevation myocardial infarction

ST-elevation myocardial infarction (STEMI) is a medical emergency that benefits from rapid access to specialized care. The objective of this study was to describe developments in patient transport via the pre-hospital emergency medical system (EMS) and its impact on clinical outcomes.

We retrospectively studied STEMI patients who underwent primary percutaneous coronary intervention between January 2008 and July 2015. Patients were divided according to type of admission. Total ischemic time (TIT), door-to-balloon time (DBT) and in-hospital and one-year clinical outcomes were assessed for each group.

A total of 764 patients were included, of whom 33.5% were transported by the EMS and 45.8% by their own means, 13.7% were transferred from another institution and 6.9% were transported by non-EMS ambulance. There was a trend for more frequent recourse to the EMS over the eight-year period. There was a higher percentage of patients with prior myocardial infarction and Killip class III/IV in the EMS group compared to the non-EMS group. Significant differences were seen between groups in reperfusion times, EMS patients having the shortest TIT and DBT (195 vs. 286 min, p<0.001 and 61 vs. 90 min, p<0.001, respectively), but no significant difference in event rates was observed. Patients presenting to the hospital early had higher rates of effective reperfusion and lower in-hospital mortality (6.9% vs. 33.9%, p<0.001).

Recourse to the EMS significantly reduced ischemic times. Although this improvement was not directly associated with significant differences in event rates, it was associated with higher rates of effective reperfusion that were reflected in lower in-hospital mortality.