Effect on Outcome of an Increase of Serum Cardiac Troponin T in Patients With Healing or Healed ST-Elevation Myocardial Infarction

Recently, an association between minimally elevated cardiac troponin levels and cardiovascular risk in the general population has been reported. However, the prevalence and clinical importance of elevated cardiac troponin T (cTnT) levels remain unclear in patients with histories of myocardial infarction (MI). In this study, 1,807 consecutive patients with ST-segment elevation MIs were prospectively studied (77.1% men; mean age 64.4 years). Venous blood samples were obtained in the chronic stage of MI (28 ± 7 days after onset), and serum cTnT levels were determined. During the average follow-up of 1,042 days, 84 patients died and 83 had nonfatal reinfarctions. Patients with cTnT levels in the highest quartile (≥0.040 ng/ml [n = 353]) had a higher incidence of all-cause death (8.2% vs 5.2%, p = 0.049) and nonfatal reinfarction (8.3% vs 5.1%, p = 0.048) than patients with cTnT levels from the lower 3 quartiles (<0.040 ng/ml [n = 1,064]). Multivariate Cox regression analysis revealed that a minimally elevated cTnT level (≥0.040 ng/ml) was a significant predictor of all-cause mortality (hazard ratio 1.79, 95% confidence interval 1.10 to 2.90, p <0.02) and nonfatal reinfarction (hazard ratio 1.50, 95% confidence interval 1.13 to 2.20, p <0.03). Subgroup analysis showed that an elevated cTnT level was also a predictor of all-cause mortality and nonfatal reinfarction in patients without heart failure. In conclusion, minimally elevated cTnT levels in the chronic stage of MI predicted long-term adverse clinical outcomes.