Effects of Tissue Plasminogen Activator and a Comparison of Early Invasive and Conservative Strategies in Unstable Angina and Non-Q-Wave Myocardial Infarction

Background Although coronary thrombosis plays a critical role in the pathogenesis of unstable angina and non-Q-wave myocardial infarction (NQMI), the effects of thrombolytic therapy in these disorders is not clear. Also, the role of routine early coronary arteriography followed by revascularization has not been established. Methods and Results Patients (n=1473) seen within 24 hours of ischemic chest discomfort at rest, considered to represent unstable angina or NQMI, were randomized using a 2x2 factorial design to compare (1) TPA versus placebo as initial therapy and (2) an early invasive strategy (early coronary arteriography followed by revascularization when the anatomy was suitable) versus an early conservative strategy (coronary arteriography followed by revascularization if initial medical therapy failed). All patients were treated with bed rest, anti-ischemic medications, aspirin, and heparin. The primary end point for the TPA-placebo comparison (death, myocardial infarction, or failure of initial therapy at 6 weeks) occurred in 54.2% of the TPA-treated patients and 55.5% of the placebo-treated patients (P=NS). Fatal and nonfatal myocardial infarction after randomization (reinfarction in NQMI patients) occurred more frequently in TPA-treated