Contribution of renal function impairment to unexplained troponin T elevations in congestive heart failure.

Background: Patients with severe congestive heart failure (CHF) often have unexplained elevations in serum concentrations of troponin T (TnT), and it is proposed that this is due to cardiac TnT release because of underlying cardiac disease. We investigated whether impaired renal function is an additional underlying phenomenon contributing to increased TnT levels in patients with CHF.

Methods: Sixty-two patients with nonischemic CHF, New York Heart Association (NYHA) class III-IV, with normal coronary angiogram and normal serum creatinine were included in the study. Baseline glomerular filtration rate (GFR) was calculated using the Cockcroft Gault equation.

Results: Although mean creatinine level was normal (0.92 +/- 0.17 mg/dL), mean GFR was low (56 +/- 16 mL/min) in the cohort. Elevated (>or=0.02 microg/L) TnT was measured in 33 patients (53%). Compared with patients with normal (<0.02 microg/L) TnT levels, patients with elevated TnT had significantly higher NYHA class (p = 0.02), longer duration of disease (p = 0.02), lower GFR (p = 0.0001), and lower LVEF (p = 0.0001). There were significant associations between TnT levels and duration of disease (r = 0.29, p = 0.01), creatinine (r = 0.30, p = 0.01), GFR (r = -0.55, p < 0.0001), and LVEF (r = -0.39, p = 0.001). Independence of these associations was evaluated in multiple linear regression analysis, and serum TnT was independently and negatively associated only with GFR (p = 0.005).

Conclusions: Renal function (GFR) correlated significantly and more strongly than cardiac function (LVEF) with the serum TnT levels in patients with CHF. This supports our hypothesis that impaired renal function causes the accumulation of troponin and is very likely the cause of unexplained elevations of serum TnT in patients severe CHF.