Experimental data suggest that transplantation of endothelial progenitor cells (EPCs) attenuates monocrotaline-induced pulmonary hypertension in rats and dogs. In addition, clinical studies suggest that autogolous progenitor cells transplantation is feasible and safe in patients with ischemic disease. This study will investigate the feasibility, safety, and initial clinical outcome of intravenous infusion of autologous EPCs in patients with idiopathic pulmonary arterial hypertension.

Inclusion Criteria:

• Clinical diagnosis of idiopathic pulmonary arterial hypertension
• in New York Heart Association (NYHA) functional class II to III
• a mean pulmonary artery pressure more than 30 mmHg on right heart catheterization
• the ability to walk ≥50 m during a standardized 6-minute walk test.

Exclusion Criteria:

• Pulmonary hypertension as a result of heart disease, pulmonary disease, sleep-associated disorders, chronic thromboembolic disease, autoimmune or collagen vascular disease, HIV infection, liver disease, NYHA functional class IV, major bleeding requiring blood transfusion, diabetes, renal dysfunction, and evidence for malignant diseases were excluded