Relation Between Troponin T and the Risk of Subsequent Cardiac Events in Unstable Coronary Artery Disease

BACKGROUND: Early risk assessment is important in patients with unstable coronary artery disease, ie, unstable angina or non-Q-wave myocardial infarction. Some previous small studies have indicated that patients with unstable angina and elevation of troponin T (tn-T) have worse short-term and long-term prognoses. In this study, the prognostic value of tn-T was evaluated and compared with other early available risk indicators. METHODS AND RESULTS: Nine hundred seventy-six patients participating in a randomized study of low-molecular-weight heparin in unstable coronary artery disease were followed for 5 months after the index episode. The risk of cardiac events increased with increasing maximal levels of tn-T obtained in the initial 24 hours. The lowest quintile (<0.06 microgram/L) constituted a low-risk group, the second quintile (0.06 to 0.18 microgram/L) an intermediate-risk group, and the three highest quintiles (> or =0.18 microgram/L) a high-risk group, with 4.3%, 10.5%, and 16.1% risk of either myocardial infarction or cardiac death, respectively. Troponin T level was identified together with age, hypertension, number of antianginal drugs, and ECG changes at rest as independent prognostic variables for myocardial infarction or cardiac death in a multivariate analysis. The prognostic value of tn-T was independent of the classification of index event into unstable angina or myocardial infarction. CONCLUSIONS: Troponin T determination is an inexpensive and widely applicable method for early risk assessment in patients with unstable coronary artery disease. The maximum tn-T value obtained during the first 24 hours provides independent and important prognostic information.