Emphysema vs. Chronic Bronchitis: What's the Difference? The role of pulmonary vascular endothelium in chronic obstructive pulmonary disease (COPD): Does endothelium play a role in the onset and progression of COPD? Elevated risk of developing COPD with e cigarette use: Study E cigarette use tied to increased COPD, asthma risk MDedge Patient Basics: Chronic Obstructive Pulmonary Disease (COPD) 2 Minute Medicine