Earlier studies have shown that administration of beraprost sodium (BPS), an orally active prostacyclin analogue, improves hemodynamics in patients with primary pulmonary hypertension (PH), but it is not known whether BPS has beneficial effects in secondary precapillary PH. The present study investigated the hemodynamic and hormonal parameters of 18 patients with secondary precapillary PH (8 patients with chronic thromboembolic PH, 7 with collagen vascular disease, and 3 with residual PH after surgery for atrial septal defect). Hemodynamics were repeatedly measured by right heart catheterization. Treatment with BPS improved New York Heart Association (NYHA) functional class in 10 of the 18 patients and significantly decreased pulmonary vascular resistance by 17% (12.9+/-1.1 to 10.7+/-1.2 Wood units, p<0.01). Circulating brain natriuretic peptide and uric acid significantly decreased from 246+/-61 to 215+/-65 pg/ml and from 6.5+/-0.6 to 5.3+/-0.3 mg/dl, respectively. In summary, BPS therapy improved NYHA functional class, hemodynamics, and hormonal parameters in patients with secondary precapillary PH. Thus, oral administration of BPS may be a new therapeutic strategy for the treatment of secondary precapillary PH.