Early stages of chronic obstructive pulmonary disease (COPD) are characterized by the loss and narrowing of terminal bronchioles in the lung resulting in 'air-trapping,' often occurring before overt emphysema manifests. Individuals with an airway-predominant phenotype of COPD display extensive lung air-trapping and are at greater cardiovascular disease (CVD) risk than COPD patients with an emphysema-predominant phenotype. We hypothesized that the degree of computed tomography (CT)-quantified lung air-trapping would be associated with greater aortic and carotid artery stiffness and lower endothelial function, known biomarkers of CVD risk. Lung air-trapping was associated with greater aortic stiffness (carotid femoral pulse wave velocity, CFPWV) (r=0.60, p=0.007) and carotid β-stiffness (r=0.75, p=0.0001) among adults with (n=10) and without (n=9) a clinical diagnosis of COPD and remained significant after adjusting for blood pressure (BP) and smoking history (pack-years) (carotid β-stiffness r=0.68, p<0.01; CFPWV r=0.53, p=0.03). The association between lung air-trapping and carotid β-stiffness remained significant after additionally adjusting for age and FEV1 (r=0.64, p=0.01). In the COPD group only (n=10), lung air-trapping remained associated with carotid β-stiffness (r=0.82, p=0.05) after adjustment for age, pack-years and FEV1. In contrast, no association was observed between CFPWV and lung air-trapping after adjustment for BP, pack-years, age and FEV1 (r=0.12, p=0.83). Lung air-trapping was not associated with endothelial function (brachial artery flow mediated dilation) in the entire cohort (p=0.80) or in patients with COPD only (p=0.71). These data suggest that carotid artery stiffness may be a mechanism explaining the link between airway- predominant phenotypes of COPD and high CVD risk.
Keywords: chronic obstructive lung disease; emphysema; flow-mediated dilation; pulse wave velocity; vascular function.