Inhaled Corticosteroids (ICS) on Pulmonary Endothelial Function in COPD

The study objective is to determine whether an ICS added for 4 weeks to a baseline treatment with a Long-Acting Beta-adrenergic Agonist (LABA) and Long-Acting Muscarinic Antagonist (LAMA) combination improves pulmonary vascular endothelial function as assessed by the vasodilator response to inhaled albuterol (endothelium-dependent vasodilation) in stable COPD patients treated with a LABA/LAMA without an ICS for at least one month.