Marked hemodynamic improvements by high-dose epoprostenol therapy in patients with idiopathic pulmonary arterial hypertension

Background: The appropriate dose range of epoprostenol is thought to be 25-40 ng · kg^-1 · min^-1 based on the results of previous studies showing that epoprostenol therapy reduced mean pulmonary artery pressure (mPAP) by 12-22% and pulmonary vascular resistance (PVR) by 32-53% compared with baseline values in patients with idiopathic pulmonary arterial hypertension (IPAH). However, the efficacy of treatment of IPAH patients with epoprostenol >40 ng · kg^-1 · min^-1 has not been determined and this was the aim of the present study. Methods and Results: The study group comprised 16 consecutive patients, none of whom died; 2 dropped out because they could not be titrated up as needed to the highest effective epoprostenol dose. Hemodynamics were evaluated in 14 IPAH patients who received high-dose epoprostenol monotherapy. The mean epoprostenol dosage was 107±40 ng · kg^-1 · min^-1 (range, 54-190 ng · kg^-1 · min^-1) and the mean duration of high-dose epoprostenol therapy was 1,355±627 days (range, 582-2,410 days). Significant decreases from baseline values were seen in mPAP (from 66±16 to 47±12 mmHg, P<0.001) and PVR (from 21.6±8.3 to 6.9±2.9 Wood units, P<0.001). Compared with the baseline state, high-dose epoprostenol therapy reduced mPAP by 30% and PVR by 68%. Conclusions: The present study suggests high-dose epoprostenol therapy is a new treatment strategy for IPAH.