Comparison of mortality patterns in patients with ST-elevation myocardial infarction arriving by emergency medical services versus self-transport (from the prospective Ottawa Hospital STEMI Registry).

Emergency medical services (EMSs) play a key role in the recognition and treatment of ST-elevation of myocardial infarction (STEMI). We sought to determine contemporary use of EMS in patients with STEMI and its relation to treatment, morbidity, and mortality patterns. Patients who arrived by EMS were compared with those who arrived by self-transport. Among 401 patients, 59.9% arrived by EMS and 40.1% by self-transport. Patients who arrived by EMS were older (p <0.001) and had higher Killip's scores (p <0.001). Door-to-needle and door-to-balloon intervals were shorter in patients who arrived by EMS (42 vs 57 minutes, p <0.001, and 124 vs 154 minutes, p <0.001, respectively). In-hospital mortality was higher in patients who used EMS (13.3% vs 5.0%, p <0.001). Patients who arrived by EMS also had higher mortality within the first hour of hospital arrival (4.2% vs 0%, p = 0.007). Multivariate analysis showed that only age and systolic blood pressure were predictors of mortality. Despite faster onset of reperfusion therapy in patients who arrived by EMS, mortality was higher. Almost 33% of these deaths occurred in the early in-hospital period, which was due to older and sicker patients having the tendency to come by EMS. Our results suggest that regional approaches are needed to trigger earlier reperfusion therapy in patients with STEMI who use EMS.