Reactive hyperemia peripheral arterial tonometry as a measure of endothelial dysfunction in COPD

Introduction: Chronic obstructive pulmonary disease is significantly associated with cardiovascular and peripheral vascular disease. The measurement of endothelial dysfunction using reactive hyperemia peripheral arterial tonometry (RH-PAT) is well documented in the field of cardiovascular research. There are no data available for COPD patients. We, therefore, investigated endothelial dysfunction in a cohort of COPD patients using RH-PAT. Methods: A total of 191 subjects with moderate to very severe COPD (n=157), smokers without COPD (n=18) and healthy controls (n=16) were consecutively recruited at a tertiary institution. The reactive hyperemia index (RHI) were associated to lung function, MMRC, BODE index, number of exacerbations, time to exacerbation and death. Results: 57% of the patients with COPD had dysfunctional endothelium compared to 31% of the healthy controls and 33% of the smokers without COPD (p=0.036). Univariate analysis showed a significant difference in RHI between healthy controls and patients with COPD (median 1.94 vs. 1.58; p=0.030), however, this difference disappeared after adjustment for age, BMI, blood pressure and pulse. There was no difference in RHI between patients with COPD and age-matched smokers without COPD (median 1.58 vs. 1.82; p=0.120). RHI did not change significantly whether the patient was in stable state or during an exacerbation (means 2.05 vs 1.91; paired T-Test, p=0.625). There was no association between RHI and body plethysmography lung function, MMRC, BODE, exacerbations or death (p≥0.05). Conclusion: Endothelial dysfunction, as measured by RH-PAT, does not appear to be either a predictor of disease severity or of outcome in COPD.