Objective: To determine the correlation between the serum level of B-natriuretic peptide (BNP) and hemodynamic variables and to evaluate the diagnostic value of BNP in patients with decompensated heart failure (HF).
Methods: BNP levels (TRIAGE BIOSITE Diagnostics, San Diego, USA) were obtained by a rapid immunofluorescence assay in 117 patients with dyspnea including cardiogenic group (75 patients) and lung disease (42 patients). Hemodynamic parameters of 53 patients [male 28, female 25, mean age (71.6 +/- 9.8) years] with HF were determined and left ventricular end-diastolic diameter (LVEDD) of all patients were measured by echocardiogram.
Results: Pulmonary capillary wedge pressure (PCWP, mm Hg), mean pulmonary arterial pressure (MPAP, mm Hg), right atrial pressure (RAP, mm Hg) and BNP (ng/L) levels according to New York Heart Association (NYHA) class were: 16.10 +/- 3.50, 22.50 +/- 4.68, 3.11 +/- 1.90, 271.25 +/- 159.29 in NYHA class II, respectively; 21.50 +/- 4.42, 28.60 +/- 9.35, 8.95 +/- 3.86, 619.58 +/- 237.48 in NYHA class III; 29.28 +/- 8.61, 36.50 +/- 12.32, 15.27 +/- 4.96, 1519.28 +/- 618.62 in NYHA class IV (P < 0.01-0.05), respectively. PCWP, MPAP, RAP and plasma BNP levels were directly proportional to cardiac function. The plasma BNP levels had also significant positive correlations with PCWP, MPAP, RAP, (r = 0.59, 0.50, 0.32, P < 0.05-0.01). BNP level [(918.48 +/- 453.25) ng/L] of the group with LVEDD (n = 24) > or = 60 mm was much higher than that of the group with LVEDD (n = 29) < 60 mm [(298.58 +/- 167.51) ng/L]. However, the latter was significantly higher than that in pulmonary dyspnea group with a normal left and right ventricular end-diastolic diameter [(35.4 +/- 26.4) ng/L, P < 0.01]. There was a great difference of BNP between cardiogenic dyspnea group [(761.30 +/- 480.47) ng/L]and lung dyspnea group [(35.4 +/- 26.4) ng/L], P < 0.01.
Conclusions: The plasma BNP levels had significant positive correlations with PCWP, MPAP, RAP. BNP is a cardiac neurohormone secreted from cardiac ventricles as a response to ventricular volume expansion and pressure overload. Rapid testing BNP should be of help to differentiate pulmonary dyspnea from cardiac etiologies.