The Changes Of Plasma Brain Natriuretic Peptide Levels In Patients With Chronic Obstructive Pulmonary Disease

Objective: To investigate the changes of the levels of plasma brain natriuretic peptide (BNP) in patients with chronic obstructive pulmonary disease (COPD) and chronic cor pulmonale (CCP). Methods: Plasma BNP levels were measured by radioimmunoassay in 37 patients(twenty men, seventeen women, mean age 67 years)with CCP at acute stage, compared with the normal control group(eleven men, six women, mean age 60 years) and simple COPD group(thirteen men, seven women, mean age 61 years), and the relationship between it and PaO2, pulmonary artery pressure(PAP) was analyzed. Measurements were repeated in 20 patients(twelve men, eight women, mean age 68 years)with CCP at remission stage after therapy in hospital. Multivariate linear regression analysis was performed between the plasma BNP levels and the possible related variables in order to screen the significative factors. Results: The levels of BNP at acute stage (75.2±14.7) pg/ml and remission stage (50.1±10.2) pg/ml for CCP group were both higher than that in the normal control group (15.3±3.7) pg/ml and simple COPD group (16.3±3.9) pg/ml (p<0.001). Plasma BNP levels were negatively correlated with PaO2(r= -0.653,p<0.01) at acute stage, but had no significant correlation at remission stage (p >0.05). In the acute stage of CCP group, BNP levels in the plasma were positively correlated with the PAP(r=0.775, p<0.01). The factors correlated to the levels of plasma BNP were right ventricular outflow tract (RVOT), alveolar-arterial oxygen difference (A-aDO2), ejection fraction (EF), forced expiratory volume in one second (FEV1) percent predicted, patients'age and PaO2. Standardized Coefficientsβof these variables were 0.501, 0.245, -0.175, -0.155, 0.084 and -0.154, respectively. Conclusions: The present study demonstrates that hypoxia and pulmonary artery hypertension (PAH) may result in elevation of plasm BNP in patients with COPD accompanied with CCP. BNP may involve in the pathophysiological process of CCP.