The term "biochemical marker" of heart failure is used to define a biochemical substance whose plasma levels correlate with the clinical and hemodynamic status and predict the prognosis of patients with heart failure. The aim of this study was to prospectively evaluate, in a single population of patients with heart failure, the correlations between the plasma levels of brain natriuretic peptide (BNP), big endothelin-1 (BET-1), tumor necrosis factor-alpha (TNF-alpha), cardiac troponin I (cTnI) and T (cTnT), the clinical presentation, and the left ventricular function.
The study population included a series of 120 patients (97 males, 81%, mean age 56+/-12 years) in NYHA functional class I (49%), II (20%), III (26%), IV (5%) who were admitted to our institution or followed up as outpatients. All patients underwent cardiologic evaluation, standard electrocardiography, two-dimensional echocardiography, and venous blood sampling on the same day.
At univariate analysis the following correlations were found to be significant: all the laboratory parameters correlated with the NYHA class (BNP r = 0.63, BET-1 r = 0.56, cTnI r = 0.25, cTnT r = 0.24, TNF-alpha r = 0.23); BNP (r = -0.39) and BET-1 (r = -0.27) with left ventricular ejection fraction; BNP (r = 0.37) and BET-1 (r = 0.21) with the degree of mitral insufficiency; BNP (r = -0.39), BET-1 (r = 0.25) and TNF-alpha (r = -0.19) with systolic blood pressure; cTnT (r = 0.34), cTnI (r = 0.33), BNP (r = 0.22) and BET-1 (r = 0.19) with heart rate; BNP with age (r = 0.33) and body mass index (r = -0.28). The plasma levels of BNP, BET-1, cTnT and cTnI were significantly higher in case of systemic or pulmonary congestion. At multiple regression analysis the following correlations were still present: BNP with the NYHA functional class (p < 0.005) and with pulmonary venous congestion (p < 0.05); BET-1 with the presence of pulmonary venous congestion (p < 0.005); TNF-alpha with the NYHA class (p < 0.05) and systolic blood pressure (p < 0.001); cardiac troponins with heart rate (p < 0.05).
The plasma concentrations of BNP and BET-1 showed the best and comparable correlations with parameters describing the clinical status of patients with heart failure, in particular with the presence of pulmonary venous congestion. The value of the plasma concentration of TNF-alpha and those of cardiac troponins were found to be limited in patients with relatively stable heart failure.