[Troponin-T monitoring in outpatients with nonischemic heart failure]

Abstract

Introduction and objective: The usefulness of prolonged troponin-T (TnT) monitoring in outpatients with nonischemic heart failure (HF) is not clear. The aim of this study was to investigate the incidence, prognostic value and determinants of a raised TnT level.

Methods: The study involved 80 outpatients (age 56+/-14 years, 69% male) with chronic stable HF (mean left ventricular ejection fraction 24+/-9%; 51 in New York Heart Association class II and 29 in class III) of non-ischemic origin, as confirmed with coronary angiography. The TnT level was measured at study entry and at every outpatient visit (median interval, 3.1 months; interquartile range [IQR], 1.8-5.0 months) in a follow-up period of 22.2+/-10.6 months. Patients were TnT+ if the level was measurable (i.e., >0.01 ng/mL).

Results: At study entry, 7 (9%) patients were TnT+. By 5 years, the cumulative incidence had reached 53%, and the median TnT level was 0.059 ng/mL (IQR, 0.023-0.100 ng/mL; range, 0.013-0.500 ng/mL). Beta-blocker therapy was associated with a reduction in incidence (hazard ratio [HR]=0.220; 95% confidence interval [CI], 0.089-0.540; P=.001) while the incidence increased with the N-terminal probrain natriuretic peptide (NT-proBNP) level (HR=1.005; 95% CI, 1.001-1.010; P=0.021). During follow-up, 14 (17.5%) patients had a cardiac event (i.e., 9 cardiac deaths and 5 urgent transplants); these occurred in 12 (50%) of the 24 TnT+ patients vs. 2 (3.6%) of the 56 TnT- patients (P< .001). After adjustment, Cox multivariate analysis showed that being TnT+ was a predictor of an adverse event (HR per 0.01 ng/mL=1.359; 95% CI, 1.037-1.782; P=.026), independently of the NT-proBNP level (HR per 500 pg/mL=1.057; 95% CI, 1.023-1.092; P=.001).

Conclusions: A measurable TnT level was frequently observed during clinical monitoring of outpatients with non-ischemic HF and indicated a poor prognosis, even when the level was low.