Increased levels of cardiac troponin-T in outpatients with heart failure and preserved systolic function are related to adverse clinical findings and outcome

Abstract

The implications of increased levels of cardiac troponin T in congestive heart failure with preserved systolic function have been poorly evaluated. We hypothesized that its presence might be related to disease severity and prognosis in this setting. Clinical, echocardiographic, 6-min walking test and laboratory data were prospectively obtained in 69 congestive heart failure outpatients with ejection fraction > or = 40%. Serial blood samples were assayed for cardiac troponin T with a third-generation immunoassay and values > or = 0.02 ng/ml were considered abnormal. Abnormal cardiac troponin T levels in at least one sample were found in 27 patients (39%, group 1). These patients were older (71.7 +/- 11 vs. 63 +/- 12.4 years, P = 0.002); more frequently hospitalized during the previous year (63 vs. 26.2%, P = 0.003), had lower systolic blood pressure (129.3 +/- 19.6 vs. 140.4 +/- 23.5 mmHg, P = 0.04), but had similar proportion of ischemic etiology (55.6 vs. 42.9%, P = 0.21) than those with normal cardiac troponin T (group 2). In groups 1 and 2, the functional class was 2.8 +/- 0.8 and 2.1 +/- 0.9 (P = 0.03), and the distance covered in 6 min was 339 +/- 100 and 386 +/- 103 m (P = 0.05), respectively. In groups 1 and 2, the 18-month congestive heart failure hospitalization-free survival was 22 and 87%, respectively (log-rank test P = 0.0003). In a Cox-proportional hazard model, functional class III-IV (hazard ratio = 5.21, 95% confidence interval: 1.43-18.96) and myocardial injury (hazard ratio = 5.51, confidence interval: 1.58-19.24) were independently associated with prognosis. Increased levels of cardiac troponin T were detected in one out of three congestive heart failure outpatients with preserved systolic function and correlated with clinical measures of disease severity and poor outcome. These findings suggest a link between ongoing myocardial injury and progressive impairment in congestive heart failure despite preserved systolic function.