Keymel S, et al. - This study entailed the characterization of the oxygen dependence of endothelial function in patients with coronary artery disease (CAD) and coexisting chronic obstructive pulmonary disease (COPD). Findings exhibited that decreased systemic oxygen levels resulted in endothelial dysfunction in CAD patients with COPD. This, in turn, underscored the relevance of cardiopulmonary interaction and the potential importance of pulmonary treatment in secondary prevention of vascular disease.