Background: To investigate the changes in plasma endothelin-1 (ET-1) concentrations in patients with congenital heart defects.
Methods: Plasma ET-1 concentrations were measured by using radio-immunoassay in 50 patients in a prospective study. In 35 patients with ventricular septal defect, 20 cases had pulmonary hypertension (group 1) and 15 cases had normal pulmonary artery pressure (group 2). The other 15 patients with atrial septal defect had normal pulmonary artery pressure (group 3). Blood samples were obtained from pulmonary artery, aorta and radial artery.
Results: Plasma ET-1 concentration in group 1 was significantly higher than those in group 2 and group 3 at all sampling sites and all different times (p < 0.01), and plasma ET-1 concentration was slightly higher in group 3 than in group 2 (p > 0.05). Plasma ET-1 concentration at aorta were also significantly higher than that at pulmonary artery in group 1 (p < 0.01). In patients with ventricular septal detect, pulmonary blood flow had a linear positive correlation with plasma ET-1 concentration (r = 0.75, p < 0.01) and there was also a significant positive correlation between plasma ET-1 concentration and pulmonary artery pressure (r = 0.68, p < 0.05). After surgical repair of the defects, plasma ET-1 concentration decreased except for 6 cases with the pulmonary resistance more than 800 dyne.sec.cm-5.
Conclusions: Plasma ET-1 concentrations are elevated in patients with congenital heart defect associated with left-to-right shunt and may have an important role in the pathogenesis of pulmonary hypertension.