Prehospital system delay in ST-segment elevation myocardial infarction care: a novel linkage of emergency medicine services and in hospital registry data

Emergency medical services (EMS) are critical in the treatment of ST-segment elevation myocardial infarction (STEMI). Prehospital system delays are an important target for improving timely STEMI care, yet few limited data are available. Using a deterministic approach, we merged EMS data from the North Carolina Pre-hospital Medical Information System (PreMIS) with data from the Reperfusion of Acute Myocardial Infarction in Carolina Emergency Departments-Emergency Response (RACE-ER) Project. Our sample included all patients with STEMI from June 2008 to October 2010 who arrived by EMS and who had primary percutaneous coronary intervention (PCI). Prehospital system delays were compared using both RACE-ER and PreMIS to examine agreement between the 2 data sources. Overall, 8,680 patients with STEMI in RACE-ER arrived at a PCI hospital by EMS; 21 RACE-ER hospitals and 178 corresponding EMS agencies across the state were represented. Of these, 6,010 (69%) patients were successfully linked with PreMIS. Linked and notlinked patients were similar. Overall, 2,696 patients were treated with PCI only and were taken directly to a PCI-capable hospital by EMS; 1,750 were transferred from a non-PCI facility. For those being transported directly to a PCI center, 53% reached the 90-minute target guideline goal. For those transferred from a non-PCI facility, 24% reached the 120-minute target goal for primary PCI. We successfully linked prehospital EMS data with in hospital clinical data. With this linked STEMI cohort, less than half of patients reach goals set by guidelines. Such a data source could be used for future research and quality improvement interventions.