Breathe-5: Bosentan Improves Hemodynamics And Exercise Capacity In The First Randomized Placebo-Controlled Trial In Eisenmenger Physiology

PURPOSE: BREATHE-5 was the first placebo-controlled trial to investigate the effects of bosentan (Tracleer®) in patients with Eisenmenger physiology (EP). EP is characterized by the development of pulmonary arterial hypertension (PAH) and consequent intracardiac right to left shunt and hypoxemia in patients with pre-existing congenital heart disease. EP has been regarded as not amenable to conventional treatments or surgery. Theoretically, some treatments may worsen the shunt and increase hypoxemia. Since EP is associated with increased endothelin expression, it has been hypothesized that patients may benefit from endothelin antagonism.