Tadalafil for Severe Pulmonary Hypertension Due to Chronic Obstructive Pulmonary Disease

Pulmonary hypertension (PH) is a frequent complication of chronic parenchymal lung diseases particularly in chronic obstructive pulmonary disease (COPD) and represents one of the major cause of all causes of PH. When present, PH contributes to more severe symptoms; exercise intolerance and can lead to right heart failure, which portends a worse prognosis and an increased mortality. Mechanisms of severe PH in chronic respiratory diseases are complex and include rarefaction of vascular bed, endothelial dysfunction and exaggerated pulmonary arterial remodeling. In patients with idiopathic pulmonary arterial hypertension (PAH), targeted medical therapies, including oral phosphodiesterase type 5 inhibitors (PDE5i), improve endothelial cell dysfunction, have vasodilatory and anti-proliferative effects on the pulmonary vasculature, reduce the right ventricular afterload and improve symptoms, exercise capacity, and clinical outcomes in randomized trials. Several studies suggested a potential effect of PDE5i in COPD on dyspnea, exertional capacity and quality of life. However, these results were based on including small number of patients with heterogenous severity of lung disease and usually without complete hemodynamic evaluation. Data are lacking regarding the benefit/risk ratio of these treatments in the context of severe PH due to COPD. The main objective to this randomized controlled trial (16 weeks) is to evaluate the efficacy and safety of an oral PDE5i, tadalafil, in patients with severe PH due to COPD.