[The changes of plasma endothelin concentration and its clinical significance in pulmonary hypertension associated with congenital heart defects].

Plasma endothelin (ET) concentration was measured by means of radioimmunoassay in 38 patients with congeital heart defects among whom 15 patients with pulmonary hypertension (PH) and 23 patients without pulmonary hypertension (non-PH). Blood samples were obtained separately from the femoral vein, right atrium, right ventricle, main pulmonary artery and the femoral artery during catherization. Plasma ET concentration in the PH group was significantly higher than that in the non-PH group at all four sampling sites. In the PH group plasma ET concentration in the pulmonary artery showed higher than that of the right ventricle and the femoral artery, which was significantly in positive correlation with pulmonary artery pressure. It is considered that the elevation of ET plays an important physiological role in the formation of pulmonary hypertension.