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 less than or equal to35%, 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 (greater than or equal to0.02 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.