Oral sildenafil improves primary pulmonary hypertension refractory to epoprostenol

Background: Epoprostenol (prostaglandin I2) has become recognized as a therapeutic breakthrough that can improve hemodynamics and survival in patients with primary pulmonary hypertension (PPH). However, a significant number of patients have PPH that is refractory to epoprostenol, and lung transplantation has been the only remaining treatment option. Methods and Results: The study subjects included 20 consecutive patients with PPH (mean pulmonary arterial pressure: 65±15 mmHg) who had received epoprostenol for more than 12 months. The patients were divided into 2 groups; responders and non-responders. In the non-responders, New York Heart Association (NYHA) functional class did not improve and mean right atrial pressure (mRA) increased to 8 mmHg or more, and additional sildenafil, a phosphodiesterase-5 inhibitor, was started. Six patients were included in the non-responders, whose mRA was 9±5 mmHg before and significantly increased to 13±3 mmHg after epoprostenol administration (p<0.05). One patient died and the other 5 patients received oral sildenafil. The mRA of 12±4 mmHg (value before sildenafil) improved to 8±5 mmHg after sildenafil administration. Three patients were classified in the NYHA functional class 4 and improved to class 3, and 2 patients were in class 3 and remained in the same class after the addition of sildenafil. Conclusions: In patients with severe PPH refractory to epoprostenol treatment, additional oral sildenafil can improve pulmonary hemodynamics and symptoms. The combination therapy of epoprostenol and sildenafil is a new medical treatment to attempt before progressing to lung transplantation for patients with PPH refractory to epoprostenol.