Plasma endothelin-1 levels in adult patients undergoing coronary revascularization

Cardiopulmonary bypass is thought to injure all endothelial cells, mainly by cell-to-cell interaction with activated granulocytes which, augmented by endothelin-1 (ET-1), enhance the generation of superoxide radicals. These radicals on the other hand, may sustain and prolong endothelial injury. In the present study, by means of a magnetic separation radioimmunoassay procedure, ET-1 levels were measured in 10 adult patients undergoing coronary artery bypass surgery, in 10 perioperative phases, in order to reconfirm and further elucidate the effect of cardiopulmonary bypass on endothelial secretion of ET-1. ET-1 levels before cardiopulmonary bypass showed a definite rising trend, especially after median sternotomy. After induction of cardiopulmonary bypass, ET-1 levels increased significantly compared with preoperative values (P < 0.01). ET-1 levels in stable angina patients during and after aortic cross-clamping were strongly and positively correlated with preoperative mean pulmonary artery pressure (r = 0.79, n = 7, P < 0.05 and r = 0.92, n = 7, P = 0.05) respectively. After the first hour in the intensive care unit, ET-1 levels in three patients with unstable angina were considerably higher than in those with stable angina, a fact that deserves further consideration and study.