Effects of right ventricular dysfunction on exercise capacity and quality of life and associations with serum NT-proBNP levels in COPD: an observational study

During the course of chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH) and right ventricular (RV) failure may develop due to elevated afterload of the RV. In those patients, exercise capacity is reduced due to pulmonary and cardiac limitations. We investigated relationships between serum N-terminal of proB-type natriuretic peptide (NT-proBNP) and RV functions with exercise capacity and quality of life in patients COPD. An observational case-control study was conducted. We enrolled 31 moderate and severe COPD patients, and 20 subjects without chronic diseases as control group. Parameters reflecting the right ventricular diastolic and systolic functions by echocardiography along with serum NT-proBNP levels were assessed. Cardiopulmonary exercise testing and Short Form-36 (SF-36) were applied. Serum NT-proBNP levels were higher in COPD patients than control group (p=0.003). Serum NT-proBNP level was found to be related with pulmonary arterial pressure. Serum NT-proBNP levels were negatively correlated with anaerobic threshold oxygen uptake (AT VO2) and peak oxygen uptake (PVO2) values. Early ventricular filling velocity (Em) was lower in COPD patients. Em wave was significantly correlated with O2 pulse. There was a positive relationship between tricuspid E/A ratio and VO2 value at AT. SF-36 domains of physical functioning, general health and role limitation due to physical disorder were significantly correlated with AT VO2, PVO2 and O2 pulse. Exercise limitation may be predicted by assessment of right ventricule functions and NT-proBNP levels and exercise limitation impairs quality of life in COPD patients.