Correlation Between Plasma Level Of N-terminal Pro-brain Natriuretic Peptide And Cardiac Functional Parameter In Patients With Chronic Heart Failure

Objective: To investigate the N-terminal pro-brain natriuretic peptide (NT-proBNP) level in patients with chronic congestive heart failure, by which to evaluate its relationship with, and its diagnostic value of heart function.Methods: Seventy-four patients with chronic heart failure (Group CHF), whom was diagnosed according to guidelines of European Society of Cardiology (ESC), and 26 healthy cases (Group control) were enrolled in this study. In Group CHF, the patients were further divided into 4 subgroups according to the classification of New York Heart Academy (NYHA), including 11, 18, 25 and 20 patients in Class I, II, III and IV, respectively. Concentration of the plasma NT-proBNP was measured by chemilumine- scence immune assay in both groups. Left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter (LVEDD) were also evaluated by echocardiography in these cases. SPSS11.5 was used for statistical analysis. Continuous variables are reported as mean±SD, and comparison between the groups was performed with the Student's t-test. The relationships between the concentrations of NT-proBNP and the other heart function parameters were evaluated by Pearson's coefficient of correlation analysis. Statistical significance was established at P<0.05.Results: 1.Relationship between the NT-proBNP level and NYHA cardiac function: Plasma NT-proBNP concentration in Group Control was 161±114pg/ml. In Group CHF, however, the NT-proBNP was significantly increased with the heart function deteriorated, as observed of 466.6±8.65 pg/ml, 559±88pg/ml, 1359.52±408pg/ml, 5114±2535pg/ml in the subgroups of NYHA Class I, II, III and IV, respectively, which were all significant greater than that in Group Control. The positive linear correlation between the NT-proBNP concentration and the cardiac function was also found (r=0.708, P<0.01). 2. Relationship between the NT-proBNP level and the parameters from echocardiography. According to the LVEDD, the patients with heart failure were further divided into two groups, with 16 cases more and 58 cases less than 60 mm LVEDD. The NT-proBNP concentration of the former(5812±2354pg/ml) was significantly higher than that of the later group(1008±607pg/ml)(P<0.01), and the NT-proBNP of each group was both significantly higher than that of the control group (P<0.01). When the LVEF was considered, the NT-proBNP concentration of the patients with LVEF less than 0.40 (3059±2558pg/ml) was significantly higher than those with LVEF more than 0.50(562±177pg/ml). Over all, the plasma NT-proBNP level was negatively correlated with LVEF (r=-0.848, P<0.01), while positively correlated with LVEDD (r=0.935, P<0.01).Conclusions: As a sensitive marker reflecting the extent of impairment of cardiac function, the plasma NT-proBNP highly associated with the heart function and the left ventricle remodeling. The detection of the plasma NT-proBNP may help to evaluate the heart function, and may further guide the treatment and prognosis evaluation in heart failure patients.