A treatment strategy for patients with pulmonary hypertension (PH) and atrial septal defect (ASD) remains unclear. This study was designed to evaluate the effects of initial repair of ASD followed by treatment with PH-specific drugs in patients with PH and ASD. Eligible patients receive transcatheter ASD closure followed by treatment with bosentan and sildenafil. Right heart catheterization is performed at baseline and at 12, 24 and 48 weeks. The primary endpoint is change in pulmonary artery pressure and pulmonary vascular resistance from baseline to follow-up. This study should provide valuable information to establish a therapeutic strategy for PH and ASD.