Therapy for pulmonary arterial hypertension due to congenital heart disease and Down's syndrome.

Background: Oral bosentan is effective in pulmonary arterial hypertension (PAH) related to congenital heart disease (CHD). In patients with Down's syndrome, the effect of bosentan is largely unknown. Aim of the study was to evaluate the long-term effects of bosentan in adult patients with CHD-related PAH with and without Down's syndrome.
Methods: WHO functional class, resting oxygen saturation, 6-minute walk test (6 MWT) and hemodynamics were assessed at baseline and after 12 months of bosentan therapy in patients with CHD-related PAH with and without Down's syndrome.
Results: Seventy-four consecutive patients were enrolled: 18 with and 56 without Down's syndrome. After 12 months of bosentan therapy, both with and without Down's syndrome patients showed an improvement in WHO functional class (Down: 2.5 ± 0.5 vs 2.9 ± 0.6, p=0.005; controls: 2.5 ± 0.5 vs 2.9 ± 0.5, p=0.000002), 6-minute walk distance (Down: 288 ± 71 vs 239 ± 74 m, p=0.0007; controls: 389 ± 80 vs 343 ± 86 m, p=0.00003), and hemodynamics (pulmonary flow, Down: 4.0 ± 1.6 vs 3.5 ± 1.4 l/m/m(2), p=0.006; controls: 3.5 ± 1.4 vs 2.8 ± 1.0 l/m/m(2), p=0.0005; pulmonary to systemic flow ratio, Down: 1.4 ± 0.7 vs 1.0 ± 0.4, p=0.003; controls: 1.1 ± 0.7 vs 0.9 ± 0.3, p=0.012; pulmonary vascular resistance index, Down: 15 ± 9 vs 20 ± 13 WUm(2), p=0.007; controls: 2 0 ± 10 vs 26 ± 15 WUm(2), p=0.002). No differences in the efficacy of therapy were observed between the two groups.
Conclusions: Bosentan was safe and well tolerated in adult patients with CHD-related PAH with and without Down's syndrome during 12 months of treatment. Clinical status, exercise tolerance, and pulmonary hemodynamics improved, regardless of the presence of Down's syndrome.
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