Pulmonary arterial hypertension (PAH) is characterized by abnormalities in endothelial and smooth muscle cell function. Prostacyclin released by endothelial cells is a potent vasodilator by increasing cyclic adenosine monophosphate. Sildenafil, an inhibitor of phosphodiesterase-5, increases cyclic guanosine monophosphate in the lungs, producing vasodilation. To test for a therapeutic benefit of the combination of a prostacyclin analogue, subcutaneous treprostinil, and sildenafil, a proof-of-concept, open-label investigational trial was initiated. Subjects with PAH in World Health Organization (WHO) functional classes II to IV receiving subcutaneous treprostinil for <6 months were evaluated with an exercise treadmill test using the Naughton-Balke protocol at baseline and after 12 weeks. Sildenafil 50 mg 3 times daily was added to the treprostinil. Mean treadmill times in seconds were compared before and after 12 weeks of therapy. Nine subjects enrolled in the trial; 7 were women (mean age 35 years). At baseline, 3 subjects were in WHO functional class II and 6 subjects were in WHO functional class III. The mean treadmill time at baseline was 465 ± 167 seconds and at 12 weeks was 656 ± 205 seconds (42% improvement, p = 0.049). All patients had symptomatic improvement. In conclusion, this pilot study of subcutaneous treprostinil with sildenafil for PAH suggests additive beneficial effects.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine