Prognostic value of very low plasma concentrations of troponin T in patients with stable chronic heart failure.

BACKGROUND Circulating cardiac troponin T, a marker of cardiomyocyte injury, predicts adverse outcome in patients with heart failure (HF) but is detectable in only a small fraction of those with chronic stable HF. We assessed the prognostic value of circulating cardiac troponin T in patients with stable chronic HF with a traditional (cTnT) and a new precommercial highly sensitive assay (hsTnT). METHODS AND RESULTS Plasma troponin T was measured in 4053 patients with chronic HF enrolled in the Valsartan Heart Failure Trial (Val-HeFT). Troponin T was detectable in 10.4% of the population with the cTnT assay (detection limit < or = 0.01 ng/mL) compared with 92.0% with the new hsTnT assay (< or = 0.001 ng/mL). Patients with cTnT elevation or with hsTnT above the median (0.012 ng/mL) had more severe HF and worse outcome. In Cox proportional hazards models adjusting for clinical risk factors, cTnT was associated with death (780 events; hazard ratio=2.08; 95% confidence interval, 1.72 to 2.52; P<0.0001) and first hospitalization for HF (655 events; hazard ratio=1.55; 95% confidence interval, 1.25 to 1.93; P<0.0001). HsTnT was associated with the risk of death in unadjusted analysis for deciles of concentrations and in multivariable models (hazard ratio=1.05; 95% confidence interval, 1.04 to 1.07 for increments of 0.01 ng/mL; P<0.0001). Addition of hsTnT to well-calibrated models adjusted for clinical risk factors, with or without brain natriuretic peptide, significantly improved prognostic discrimination (C-index, P<0.0001 for both outcomes). CONCLUSIONS In this large population of patients with HF, detectable cTnT predicts adverse outcomes in chronic HF. By the highly sensitive assay, troponin T retains a prognostic value at previously undetectable concentrations.