Prognostic value of quantitative troponin T measurements in unstable angina/non-ST-segment elevation acute myocardial infarction treated early and predominantly with percutaneous coronary intervention

Purpose To evaluate the effect of baseline cardiac troponin T measurements on in-hospital and long-term outcomes in patients with unstable angina/non-ST-segment elevation myocardial infarction who are treated with an early invasive strategy. Methods We conducted a prospective cohort study involving 1024 consecutive patients with unstable angina/non-ST-segment elevation myocardial infarction. Patients were stratified according to quantitative troponin T measurements on admission, and underwent coronary angiography and subsequent coronary stenting of the culprit lesion as the primary revascularization strategy within 24 hours. The primary endpoint was all-cause mortality. Results The risk of in-hospital and long-term mortality increased with absolute levels of troponin T. In-hospital mortality was 0.7% (3/449) in patients with levels <0.010 μg/L, 2.0% (4/197) in those with levels from 0.010 to 0.035 μg/L, 3.2% (6/186) in those with levels from 0.035 to 0.229 μg/L, and 4.7% (9/192) in patients with levels >0.229 μg/L. Cumulative 2-year mortality rates were 2.8%, 8.0%, 10.5%, and 14.8% from the lowest to highest troponin T groups (P<0.001). In contrast, the risk of nonfatal myocardial infarction assumed an inverted U-shaped curve and was lower in the lowest and highest troponin T groups. Conclusion Troponin T remains a strong predictor of mortality, even at low levels, in patients with unstable angina/non-ST-segment elevation myocardial infarction who are treated with early revascularization. The risk associated with elevated levels is linear for death but not for myocardial infarction.