Bosentan for the treatment of pulmonary arterial hypertension associated with congenital heart defects

BACKGROUND: Bosentan is an effective first-line therapy in New York Heart Association (NYHA) III patients with idiopathic pulmonary arterial hypertension (PAH). Pre-clinical data support the rationale for the potential benefit of bosentan in PAH associated with congenital heart disease (CHD). MATERIALS AND METHODS: We performed a retrospective analysis of patients with PAH-associated CHD who were treated with bosentan on top of conventional therapy. Bosentan was started at 62.5 mg bid for 4 weeks, then titrated to 125 mg bid. New York Heart Association (NYHA) functional class, 6-min walking distance (6MWD), Borg dyspnoea index, arterial oxygen saturation and cardiopulmonary haemodynamic data (cardiac output, pulmonary blood flow and systemic and pulmonary vascular resistances) were collected at baseline and at follow up. RESULTS: Twenty-seven patients (23 females, mean 35 +/- 15 years) with NYHA class III-IV PAH-associated CHD (not repaired in 23 cases) were treated with bosentan for a mean 18.3 +/- 9.9 months. Bosentan improved 6MWD from 298 +/- 92 m at baseline to 355 +/- 82 m at 3 months (P = 0.0002) and to 364 +/- 92 m (P = 0.0001) at the last follow up (mean 15.2 +/- 9.7 months). At the last follow up, 13 patients had improved (= 1 NYHA class) and 14 remained stable. A favourable effect was observed in pulmonary blood flow and pulmonary vascular resistance for the 11 available patients. No change in pulse oximetry or liver enzyme elevation was reported. CONCLUSIONS: Bosentan improves exercise capacity, functional class and haemodynamics in most patients with PAH-associated CHD, without serious side-effects, suggesting bosentan may be an important treatment option for these patients.