Association Between Prehospital Time Intervals and ST-Elevation Myocardial Infarction System Performance

Background-Among individuals experiencing an ST segment-elevation myocardial infarction, current guidelines recommend that the interval from first medical contact to percutaneous coronary intervention be <= 90 minutes. The objective of this study was to determine whether prehospital time intervals were associated with ST-elevation myocardial infarction system performance, defined as first medical contact to percutaneous coronary intervention. Methods and Results-Study patients presented with an acute ST-elevation myocardial infarction diagnosed by prehospital ECG between May 2007 and March 2009. Prehospital time intervals were as follows: 9-1-1 call receipt to ambulance on scene <= 10 minutes, ambulance on scene to 12-lead ECG acquisition <= 8 minutes, on-scene time <= 15 minutes, prehospital ECG acquisition to ST-elevation myocardial infarction team notification <= 10 minutes, and scene departure to patient on cardiac catheterization laboratory table <= 30 minutes. Time intervals were derived and analyzed with descriptive statistics and logistic regression. There were 181 prehospital patients who received percutaneous coronary intervention, with 165 (91.1%) having complete data. Logistic regression indicated that table time, response time, and on-scene time were the benchmark time intervals with the greatest influence on the probability of achieving percutaneous coronary intervention in <= 90 minutes. Individuals with a time from scene departure to arrival on cardiac catheterization laboratory table of <= 30 minutes were 11.1 times (3.4 to 36.0) more likely to achieve percutaneous coronary intervention in <= 90 minutes than those with extended table times. Conclusions-In this patient population, prehospital timing benchmarks were associated with system performance. Although meeting all 5 benchmarks may be an ideal goal, this model may be more useful for identifying areas for system improvement that will have the greatest clinical impact. (Circulation. 2010;122:1464-1469.)