Acute effect of a dual ETA–ETB receptor antagonist on pulmonary arterial vasculature in preterm lamb fetuses with surgically induced diaphragmatic hernia

Purpose To study the effects of tezosentan, a dual ETA and ETB receptor antagonist on the cardiopulmonary profile in a fetal lamb model of CDH in utero. Methods A diaphragmatic hernia was surgically created at day 75 of gestation. During a 45 min of tezosentan perfusion (1 mg/kg), hemodynamic parameters (pulmonary and aortic pressures, left pulmonary and aortic flows, left auricle pressure, heart rate) were measured at day 135 of gestation. Age-matched fetal lambs served as control animals. Secondarily, parietal tension of vessels rings of pulmonary arteries was assessed in organ baths under increasing concentration of tezosentan. Results In CDH group, under perfusion of tezosentan, pulmonary artery pressure decreased from 45.8 ± 4.1 to 37.6 ± 5.9 mmHg ( P