Objective: To investigate the preliminary efficacy and safety of ambrisentan, a selective endothelin receptor antagonist, in patients with pulmonary arterial hypertension (PAH).
Methods: A total of 15 patients with PAH, including 10 patients with idiopathic PAH and 5 patients with associated connective-tissue disease, received 2.5 mg or 5 mg of ambrisentan once daily for 12 weeks. Before and after 12 weeks treatment, 6-minute walk test (6-MWD), WHO functional classification (WHO FC) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured.
Results: After 12 weeks treatment, the 6-MWD was significantly increased [(376.5 ± 108.2) m vs.(460.3 ± 95.7) m, P = 0.021] and the systolic pulmonary artery was significantly decreased [(85.0 ± 33.3) mm Hg (1 mm Hg = 0.133 kPa)vs. (70.5 ± 30.5) mm Hg,P = 0.015] and NT-proBNP was significantly reduced [892.0 (99.0-2245.0) ng/L vs. 205.0 (56.0-534.0) ng/L, P = 0.026] than before treatment. WHO FC was improved in 4 patients after 12 weeks treatment. No patient was withdrawn from this study for safety reasons.
Conclusions: Ambrisentan treatment can effectively improve the exercise capacity, and reduce systolic pulmonary artery pressure and NT-proBNP in PAH patients. Ambrisentan use is safe and could be well tolerated in Chinese PAH patients.