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 I 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 11 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 I 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.