Ability of minor elevations of troponins I and T to predict benefit from an early invasive strategy in patients with unstable angina and non-ST elevation myocardial infarction: Results from a randomized trial. (ORIGINAL CONTRIBUTION)

Patients with a heart attack or unstable chest pain who also have increased blood levels of cardiac troponins may benefit from aggressive therapy including angiography and angioplasty to open blocked coronary arteries. Cardiac troponins are proteins produced by the heart when heart muscle is damaged.
Context Cardiac troponins I (cTnl) and T (cTnT) are useful for assessing prognosis in patients with unstable angina and non-ST-segment elevation myocardial infarction (UA/NSTEMI). However, the use of cardiac troponins for predicting benefit of an invasive vs conservative strategy in this patient population is not clear. Objective To prospectively test whether an early invasive strategy provides greater benefit than a conservative strategy in acute coronary syndrome patients with elevated baseline troponin levels. Design Prospective, randomized trial conducted from December 1997 to June 2000. Setting One hundred sixty-nine community and tertiary care hospitals in 9 countries. Participants A total of 2220 patients with acute coronary syndrome were enrolled. Baseline troponin level data were available for analysis in 1821, and 1780 completed the 6-month follow-up. Interventions Patients were randomly assigned to receive (1) an early invasive strategy of coronary angiography between 4 and 48 hours after randomization and revascularization when feasible based on coronary anatomy (n=1114) or (2) a conservative strategy of medical treatment and, if stable, predischarge exercise tolerance testing (n= 1106). Conservative strategy patients underwent coronary angiography and revascularization only if they manifested recurrent ischemia at rest or on provocative testing. Main Outcome Measure Composite end point of death, MI, or rehospitalization for acute coronary syndrome at 6 months. Results Patients with a cTnl level of 0.1 ng/mL or more (n= 1087) experienced a significant reduction in the primary end point with the invasive vs conservative strategy (15.3% vs 25.0%; odds ratio [OR], 0.54; 95% confidence interval [CI], 0.40-0.73). Patients with cTnl levels of less than 0.1 ng/mL had no detectable benefit from early invasive management (16.0% vs 12.4%; OR, 1.4; 95% CI, 0.89-2.05; P Conclusion In patients with clinically documented acute coronary syndrome who are treated with glycoprotein llb/llla inhibitors, even small elevations in cTnl and cTnT identify high-risk patients who derive a large clinical benefit from an early invasive strategy.