Delays in Reperfusion of Patients with ST Elevation Myocardial Infarction: According to Mode of Transportation and Arrival Time

ABSTRACT

PURPOSE: The aim of this study was to evaluate the time delays in reperfusion of patients with ST elevation myocardial infarction (STEMI) according to the mode of transportation and patient arrival time. METHODS: An observational study of patients with STEMI treated with primary percutaneous coronary intervention (PCI) was performed from January 2004 to May 2009. The patients were classified into several subgroups according to the transportation method (self-transportation, EMS, and transfer) and patient arrival time (regular hours weekdays, 7 AM~6 PM, off-hours weekdays, 6 PM~7 AM, weekend and holiday). The symptom-to-door time (STDT), door-to-balloon time (DTBT), and the timeline to reperfusion were compared in each group. RESULTS: The median STDTs, DTBTs and the percent of the timeline to reperfusion (DTBT < or =90 min) differed significantly according to the transportation mode (p<0.001, respectively). Especially, the transfer group had longer median STDT (200 min, IQR 120~330), shorter median DTBT (80 min, IQR 66~102) and a significantly higher rate of achieving a timely DTBT (64.8%), compared to the other groups (self-transport and EMS use). Compared to the regular hour group, the offhour group had a shorter STDT (129 min vs. 180 min, p=0.016) and longer DTBT (99 min vs. 81 min, p<0.001). The percent of patients achieving a timely DTBT was much lower during off-hours (41.1% vs. 61.5%, p<0.001). CONCLUSION: The results of this study showed that the transfer group and regular hour group had a significantly shorter median DTBT, and the timeline for reperfusion was longer in the transfer group compared to the regular hour group in this study.