Rationale: It is estimated that 30 to 70% of subjects with advanced chronic obstructive pulmonary disease (COPD) have clinically significant pulmonary vascular disease (PVD). PVD is in part mediated by vascular remodeling including inflammation and endothelial dysfunction present even in smokers with normal lung function. Objective analysis of pulmonary vascular morphology on CT may provide robust metrics of vascular disease in smokers which are predictive of clinically meaningful processes.