Low lung diffusing capacity is associated with high cardio-ankle vascular index in patients with chronic obstructive pulmonary disease

Previous studies have demonstrated that arterial stiffness is independently associated with the severity of pulmonary emphysema observed on computed tomography (CT) in patients with chronic obstructive pulmonary disease (COPD). An inverse correlation exists between emphysema severity on CT image and lung diffusing capacity; however, the relationship between lung diffusing capacity and arterial stiffness in patients with COPD remains unclear. We retrospectively analyzed the data of 30 patients with COPD. Percent predicted diffusing capacity of the lung for carbon monoxide divided by alveolar volume (%DLco/VA) was used as an index of lung diffusing capacity. We used the Goddard score as an index of the severity of pulmonary emphysema on CT image and cardio-ankle vascular index (CAVI) as an index of arterial stiffness. CAVI was inversely correlated with %DLco/VA (r = −0.539, p = 0.002) but not correlated with Goddard score (rs = 0.236, p = 0.209). None of the other respiratory parameters investigated, including forced expiratory volume in the first second (FEV1), FEV1/forced vital capacity ratio, and percent predicted FEV1, were correlated with CAVI. In multiple regression analysis, systolic blood pressure (β = 0.404, p = 0.006), %DLco/VA (β = −0.379, p = 0.012), and modified Borg scale score for dyspnea (β = 0.304, p = 0.033) were significant predictors of CAVI. Lung diffusing capacity is a significant independent predictor of arterial stiffness in patients with COPD. The evaluation of %DLco/VA in patients with COPD might be useful for predicting high CAVI and the development of cardiovascular disease in the future.