Systemic sclerosis-related pulmonary arterial hypertension (PAH) is a severe disease affecting about 1000 patients in France. In 2008, all scleroderma patients are screened for PAH by a yearly cardiac Doppler ultrasonography. The pathogenesis of systemic sclerosis-related PAH is poorly known but it seems that besides common arteriolar remodeling (media hypertrophy, intimal thickening, endothelial proliferation), venular lesions suggesting obstructive venous disease and inflammatory lesions may be also be involved. Prostacyclin and analogues, phosphodiesterase-5 inhibitors (sildenafil) and endothelin-1 receptor antagonists are proposed as specific treatments for systemic sclerosis-related PAH. Unlike bosentan, which is non-selective, inhibiting both ETA and ETB receptors, sodium sitaxentan is highly selective for ETA receptors; this could favor pulmonary vasodilation.