Troponin, B-type natriuretic peptides and outcomes in severe heart failure: differences between ischemic and dilated cardiomyopathies.

BACKGROUND: Ischemic (ISCM) and idiopathic dilated (IDCM) cardiomyopathies have different responses to therapy and outcomes. Both may demonstrate elevations in troponin and B-type natriuretic peptides, but biomarker levels have not been reported to differ as a function of the etiology of heart failure (HF). Accordingly, we compared these biomarkers in patients with chronic HF. HYPOTHESIS: Biomarker levels of troponin T, troponin I, B-type natriuretic peptide (BNP), and N-terminal prohormone brain natriuretic peptide (NT-proBNP) are quantitatively different between ischemic and idiopathic dilated etiologies of chronic HF.
METHODS: Forty patients (27 male, 68 +/- 2 years; LVEF 25 +/- 1%; NYHA Class III-IV) admitted to hospital for acute HF were studied. Biomarkers were drawn at admission prior to treatment intervention.
RESULTS: Of the 40 patients, 27 had ISCM and 13 IDCM. Baseline clinical characteristics were similar with the exception of GFR. cTnT, cTnI, and BNP levels were higher in ISCM patients (cTnT: 0.373 +/- 0.145 vs. 0.064 +/- 0.016 ng/mL, p < 0.05; cTnI: 2.02 +/- 0.76 vs. 0.21 +/- 0.11 ng/mL, p < 0.05; BNP: 776 +/- 91 vs. 532 +/- 85 pg/mL, p < 0.05). Cardiovascular mortality during follow up (10 +/- 1 months) was 48% in patients with ISCM and 23% with IDCM (p < 0.05).
CONCLUSIONS: Patients with acutely decompensated chronic HF have elevations in troponin and BNP. These elevations, as well as mortality are significantly higher in patients with ISCM compared to IDCM. The differential levels in biomarkers may be due to differences in disease pathogenesis, and fit with the adverse prognosis in these patients.