Transition from Bosentan to Ambrisentan in Pulmonary Arterial Hypertension: A Single-Center Prospective Study

BACKGROUND: Pulmonary hypertension patients experienced a high financial burden due to the high cost of drug therapy, high incidence of comorbidities and hospitalizations. Endothelin receptor antagonists (ERAs) in PAH treatment showed a high cost. While ambrisentan has been covered by medical insurance of a local government of China, there has been a drug transition from bosentan to ambrisentan in treating PAH patients. We evaluated the safety, efficacy and tolerability of ambrisentan after drug transition. METHODS: Liver and renal functions were inspected at baseline, month 1, 3 and 6. NT-proBNP, echocardiographic variables, WHO functional class (WHO-FC), 6-minute walking distance (6MWD) were measured in the baseline and month 6 to evaluate the safety and efficacy. Quality of life (QOL) scale was used in the baseline and month 6 to investigate the tolerability and quality of life of PAH patients. RESULTS: Among 224 PAH patients, 49 stable PAH patients meet the inclusion criteria were enrolled, among which three patients discontinued during the study. Our results showed no difference in 6-minute walking distance (6MWD) of PAH patients from baseline and month 6. The liver and renal function, N-terminal pro-brain natriuretic peptide (NT-proBNP), WHO functional class (WHO-FC) showed no difference either. For echocardiography parameters, the left ventricular end-diastolic dimension (LVEDD) of month 6 decreased. Other parameters were no significant difference from the baseline. There was no difference in the QOL scale between baseline and month 6. CONCLUSION: Our results suggested that it is safe and tolerable for stable PAH patients to transition from bosentan to ambrisentan without influencing hematologic parameters or heart function.