Endothelin Receptor Antagonists are an Effective Long Term Treatment Option in Pulmonary Arterial Hypertension Associated with Congenital Heart Disease With or Without Trisomy 21

IntroductionTraditionally, treatment options for patients with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) are limited. Bosentan has been shown to improve pulmonary haemodynamics and exercise tolerance short term but long term clinical studies are lacking.AimTo report long term efficacy and safety data with endothelin receptor antagonists (ERA) in patients with PAH associated CHD.MethodsProspective, open label, uncontrolled, single centre study of 53 patients (33 females, 17 Trisomy 21, mean age 34 ± 12 years) prescribed ERA (48 bosentan, 5 sitaxentan) from 2003 to August 2009. Outcome measurements of oxygen saturation (SaO2), WHO functional class, 6-minute walk test distance (6MWD) and adverse events were analysed.ResultsMean duration of therapy was 15 ± 13 months in 53 patients with CHD. Four patients failed ERA, seven died (five progressive RHF) and one delisted from transplantation. No abnormal liver transaminases occurred on bosentan, with one case on sitaxentan. After 3, 6, 12, 18 and 24 months of treatment a significant improvement was seen in WHO functional class (mean 3.15 vs 2.8 vs 2.5 vs 2.5 vs 2.4 vs 2.4; p < 0.01) and 6MWD (344 ± 18 vs 392 ± 17 vs 411 ± 17 vs 420 ± 17 vs 442 ± 18 vs 417 ± 23: p < 0.0005, p < 0.01) compared with baseline. The Trisomy 21 and PAH-CHD showed a significant improvement in 6MWD at 6 and 12 months (263 ± 24 vs 348 ± 29 vs 360 ± 32, p < 0.01, p < 0.05) respectively. No changes in SaO2, BNP, RV or LV function were demonstrated during follow-up.ConclusionThis large single centre study demonstrates that endothelin receptor antagonism is an effective and safe treatment in PAH associated CHD with or without Trisomy 21. The improvements in exercise tolerance are similar to reported benefits in other forms of PAH.