In the present study, the investigators wish to address the effect of a glucocorticoid/long-acting beta-agonist preparation on endothelial function in COPD patients who do not currently smoke (ex-smokers) by measuring endothelium-dependent (albuterol response) and endothelium-independent (NTG response) vasodilation in the bronchial artery, reflecting endothelium-dependent and endothelium-independent vasodilation (drug-induced increase in Qaw, ΔQaw). With this approach the investigators will test the hypothesis that in stable ICS-naïve COPD patients, endothelium-dependent vasodilation is restored with a glucocorticoid/long-acting beta-agonist preparation, presumably resulting from the glucocorticoid component.