Diuretics, plasma brain natriuretic peptide and chronic obstructive pulmonary disease.

BACKGROUND Brain natriuretic peptide (BNP) is associated with increased myocardial stretching. This study aims to assess the effect of mild diuretics on plasma BNP levels in patients with an acute exacerbation of chronic obstructive pulmonary disease (COPD) who have high plasma concentrations of BNP. METHODS Thirty consecutive patients with an acute exacerbation of COPD without any clinical evidence of cor pulmonale who had elevated plasma BNP concentrations (group 1) and 15 patients with stable COPD as controls (group 2) participated in this study. A mild diuretic treatment in addition to the standard treatment for an acute attack of COPD was randomised to 15 patients in group 1 (group 1A). The remaining patients in group 1 only took standard treatment for acute COPD exacerbation (group 1B). Plasma BNP concentrations were measured on admission and repeated on the 5th and 10th days. RESULTS There was a significant decrease in plasma BNP concentrations, more striking in group 1A than 1B. Both in group 1A and 1B, the fall in plasma BNP concentrations was independent of either presence or absence of right ventricular dysfunction on echo evaluation. CONCLUSION Adding mild diuretics to the standard treatment for an acute attack of COPD may rapidly reduce plasma BNP levels in COPD patients with acute exacerbations who have high plasma BNP levels without any clinical evidence of cor pulmonale.