Pulmonary rehabilitation and endothelial function in patients with chronic obstructive pulmonary disease: A prospective cohort study

Background: Chronic obstructive pulmonary disease (COPD) is associated with subclinical atherosclerosis and endothelial dysfunction, thereby leading to increased cardiovascular risk. In the present study, we evaluated the changes in endothelium-dependent flow-mediated dilation (FMD) in a cohort of severe COPD patients undergoing pulmonary rehabilitation. Methods: Consecutive COPD patients referred to our Pulmonary Rehabilitation Unit were screened for inclusion. All study procedures were performed at hospital admission and discharge. Results: Of 78 patients screened for eligibility, a total of 40 participants (67.5% males, median age 72.5 years) were included. After pulmonary rehabilitation, a significant improvement in functional parameters, exercise capacity, and measures of disability and quality of life were documented. FMD changed from 3.25% (IQR: 2.31-4.26) to 4.95% (IQR: 3.57-6.02), corresponding to a 52.3% increase of its median value (P < 0.001). Significantly lower changes in FMD were documented in COPD patients with hypercholesterolemia as compared to those without (+0.33% +/- 1.61 vs. +1.62% +/- 1.59, P = 0.037). Changes in FMD (Delta FMD) were positively associated with changes in forced expiratory volume in 1 s (FEV1), when expressed both as absolute values (Delta FEV1) (r = 0.503, P = 0.002) and as percentages of predicted values (Delta FEV1%) (r = 0.608; P < 0.001). In multiple linear regressions, after adjusting for major cardiovascular risk factors, Delta FEV1 (beta=0.342; P = 0.049) and Delta FEV1% (beta=0.480; P = 0.015) were both confirmed as independent predictors of Delta FMD. Conclusions: Results of our study suggest that endothelial function may improve in COPD after pulmonary rehabilitation. The potential beneficial effect in terms of cardiovascular risk prevention should be evaluated in ad hoc designed studies.