Relationship of emphysema and airway disease assessed by CT to exercise capacity in COPD

Summary Objective To assess the association of emphysema and airway disease assessed by volumetric computed tomography (CT) with exercise capacity in subjects with chronic obstructive pulmonary disease (COPD). Methods We studied 93 subjects with COPD (Forced Expiratory Volume in 1 s [FEV1 ] %predicted mean ± SD 57.1 ± 24.3%, female gender = 40) enrolled in the Lung Tissue Research Consortium. Emphysema was defined as percentage of low attenuation areas less than a threshold of −950 Hounsfield units (%LAA-950) on CT scan. The wall area percentage (WA%) of the 3rd to 6th generations of the apical bronchus of right upper lobe (RB1) were analyzed. The 6-min walk distance (6MWD) test was used as a measure of exercise capacity. Results The 6MWD was inversely associated with %LAA-950 ( r = −0.53, p