INTRODUCTION:Treatment options for patients with pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD) are limited. Bosentan has been shown to improve pulmonary haemodynamics and exercise tolerance short term in these patients but long term clinical studies are lacking.

AIM: To report long term efficacy and safety data with endothelin receptor antagonists (ERA) in patients with PAH associated CHD.

METHODS: Prospective, single centre study of 44 patients (28 females, 15 Trisomy 21, mean age 32±11 years) prescribed ERA (39 bosentan, 5 sitaxentan) from 2003 to 2008. Outcome measurements of oxygen saturation (SaO2), WHO class, 6MWD, echocardiographic parameters, BNP and adverse events were analysed.

RESULTS: Mean duration of therapy was 16±13 months in 27 simple CHD and 17 complex CHD (single ventricle physiology). Four patients failed ERA, three died (2 progressive RHF. No abnormal liver transaminases occured on bosentan, one case on sitaxentan). After 3 and 6 months of treatment significant improvement seen in WHO class (mean 3.16 vs 2.7 vs 2.47, p<0.01, p<0.01) and 6MWD (339±21 vs 401±19 vs 423±20, p < 0.01, p < 0.01) compared with baseline. Trisomy 21 and complex CHD subgroup significantly improved 6MWD at 6 months (257± 30 vs 345±27, p=0.02; 307±26 vs 356±34, p=0.02) respectively. No changes in SaO2, RV or LV function (echocardiographic) were demonstrated.

CONCLUSION: This large single centre study shows ERA is an effective and safe treatment in PAH associated CHD with/without Trisomy 21. The improvements in exercise tolerance are similar to reported benefits in other forms of PAH.