Importance of time to reperfusion for 30-day and late survival and recovery of left ventricular function after primary angioplasty for acute myocardial infarction

Objectives. The purpose of this study was to evaluate the importance of time to reperfusion for outcomes after primary angioplasty for acute myocardial infarction. Background. Survival benefit of thrombolytic therapy for acute myocardial infarction is strongly dependent on time to treatment. Recent observations suggest that time to treatment may be less important for survival with primary angioplasty. Methods. Consecutive patients (n = 1,352) with acute myocardial infarction treated with primary angioplasty were followed for up to 13 years. Paired acute and follow-up ejection fraction data were obtained at cardiac catheterization in 606 patients. Results. Reperfusion was achieved within 2 h in 164 patients (12%), Thirty day mortality was lowest with early reperfusion (4.3% at <2 h vs. 9.2% at greater than or equal to 2 h, p = 0.04) and was relatively independent of time to reperfusion after 2 h (9.0% at 2 to 4 h, 9.3% at 4 to 6 h, 9.5% at >6 h). Thirty-day-plus late cardiac mortality was also lowest with early reperfusion (9.1% at <2 h vs, 16.3% at greater than or equal to 2 h, p = 0.02) and relatively independent at time to reperfusion after 2 h (16.4% at 2 to 4 h, 16.9% at 4 to 6 h, 15.6% at >6 h). Improvement in left ventricular ejection fraction was greatest in the early reperfusion group and relatively modest after 2 h (6.9% at <2 h vs. 3.1% at greater than or equal to 2 h, p = 0.007), Conclusions. Time to reperfusion, up to 2 h, is important for survival and recovery of left ventricular function. After 2 h, recovery of left ventricular function is modest and survival is relatively independent of time to reperfusion. These data suggest that factors other than myocardial salvage may be responsible for survival benefit in patients treated with primary angioplasty after 2 h, (C) 1998 by the American College of Cardiology.