Applicability of Cardiac Troponin T and I for Early Risk Stratification in Unstable Coronary Artery Disease

BACKGROUND: Studies have demonstrated that troponin T is a strong independent indicator of a poor prognosis in patients with unstable coronary artery disease. Up to the present, no study has compared the prognostic value of troponin T with that of troponin I in the same cohort of patients. METHODS AND RESULTS: Patients (n=516) suspected of having unstable coronary artery disease were investigated. Follow-up was done after 30 days, and the occurrences of cardiac death, acute myocardial infarction, refractory angina pectoris, and recurrent angina pectoris were registered. Elevated levels of troponin T (> or = 0.10 microg/L) were associated with an increased risk of cardiac death at 30 days compared with patients with normal levels, 3.2% versus 0.4% (P=.014). Troponin I values above the chosen cutoff (2.0 microg/L) were similarly found to be an indicator of increased risk of cardiac death, 3.2% versus 0.7% (P=.026). With regard to the composite end point of cardiac death/acute myocardial infarction, the troponins were strong independent indicators of adverse outcome. CONCLUSIONS: In patients suspected of having unstable coronary artery disease, both troponin T and troponin I provide independent prognostic information with regard to cardiac death and acute myocardial infarction.