Implications of elevated cardiac troponin T in ambulatory patients with heart failure: a prospective analysis.

BACKGROUND: Elevated concentrations of cardiac troponin T (TnT) have been reported in patients hospitalized for decompensated heart failure (HF). We assessed whether elevated TnT levels are associated with the severity, etiology, and prognosis of HF in stable, ambulatory patients.
METHODS: From 1998-1999, we prospectively collected data from 136 ambulatory patients with HF, New York Heart Association functional class II to IV, ejection fraction < or =35%, and no recent unstable angina, myocardial infarction, surgery, or coronary revascularization. Blood was obtained and analyzed by immunoassay for TnT, and patients were followed for 14.0 +/- 4.3 months for death or HF hospitalization (primary end point) and other adverse cardiovascular outcomes.
RESULTS: Thirty-three patients (24%) had an elevated TnT level (> or =0.02 ng/mL). Mean TnT concentration did not differ by etiology of HF (0.002 +/- 0.03 ng/mL vs 0.02 +/- 0.04 ng/mL for ischemic and nonischemic etiologies, P =.25). Compared with patients with normal (undetectable) levels of TnT, patients with elevated TnT were significantly older, had worse functional class, and had poorer renal function. Elevated TnT concentrations were associated with increased relative risks (RR) of death or HF hospitalization (RR 2.7, 95% CI 1.7-4.3, P =.001) and death alone (RR 4.2, 95% CI 1.8-9.5, P =.001) during follow-up. Elevated TnT and New York Heart Association class were significant, independent predictors of death or HF hospitalization. Increased age and serum creatinine concentrations were significant independent predictors of death alone.
CONCLUSIONS: Nearly one fourth of ambulatory patients with chronic HF have ongoing myocardial necrosis as shown by abnormal TnT values, which are associated with increased mortality and morbidity.