Efficacy and Limitations of Continuous Intravenous Epoprostenol Therapy for Idiopathic Pulmonary Arterial Hypertension in Japanese Children

BACKGROUND: There is little data on the long-term effects of continuous intravenous epoprostenol for children with idiopathic pulmonary arterial hypertension (IPAH) in Japan. METHODS AND RESULTS: Thirty-one IPAH patients younger than 18 years old who had begun epoprostenol therapy at Toho University Omori Medical Center between January 1999 and June 2004 were reviewed. During a mean follow up of 3.4 years, the rate of those who survived or did not undergo a lung transplantation among the 27 patients who received home infusion therapy of epoprostenol was 100% at 1 year, 96.3% at 2 years, and 79.4% at 3 years. In 82% of survivors, the World Health Organization functional class was changed from III or IV to II according to improvements in the plasma brain natriuretic peptide level and the distance walked in 6 min during the follow-up period. In most cases, mean pulmonary artery pressure and the ratio of pulmonary to systemic vascular resistance remained high, although the cardiac index had improved to within a normal range 1 year after the initiation of epoprostenol. Therefore, sildenafil was administered as an additional therapy to 16 patients who presented with sustained severe PAH. CONCLUSIONS: Continuous IV epoprostenol certainly improves survival and exercise tolerance in childhood IPAH, although the improvement of pulmonary vascular resistance regardless of long-term epoprostenol therapy is insufficient. Therefore, the addition of a new drug, such as sildenafil, is recommended to be administered in adjunction with epoprostenol.