Background: The present study aimed to elucidate the pathophysiological roles of endothelin (ET)-1 in patients with pulmonary hypertension and pulmonary vascular obstructive disease secondary to congenital heart disease and compare the plasma levels of ET-1 between children with and without Down syndrome.
Methods: Subjects comprised 32 children with congenital heart disease aged 0.5-14 months. Patients were classified into two groups: those with Down syndrome (Group D, n = 16); and those with nonDown syndrome (Group ND, n = 16). Heparinized blood samples were taken from a radial arterial line and plasma ET-1 levels were measured preoperatively, during cardiopulmonary bypass (CPB), a few minutes after termination of CPB, and 2, 6 and 24 h after discontinuation of CPB.
Results: Plasma ET-1 levels were significantly higher in Group D than in Group ND at all times except for a few minutes after termination of CPB. In both groups, peak ET-1 values were obtained at 6 h after CPB. At 24 h after CPB, ET-1 concentrations returned to baseline levels before CPB in Group ND, but not in Group D. A correlation was identified between preoperative pulmonary to systemic pressure ratio and ET-1 concentration before and after CPB in both groups.
Conclusions: Pre- and postoperative plasma ET-1 concentrations reflect pre- and postoperative pulmonary artery conditions in both groups. Specific features in Down syndrome could be associated with ET injury and might cause persistent increases in ET concentration and prolong artificial respiration.