Temporal synthesis and release of endothelin within the systemic and myocardial circulation during and after cardiopulmonary bypass: Relation to postoperative recovery

Objective:To determine endothelin levels in arterial, pulmonary, and myocar dial vascular compartments in patients undergoing coronary artery bypass gr aft surgery and to examine the influence of endothelin on postoperative rec overy. Design: Prospective, clinical study. Setting: University hospital. Participants: Fifty patients undergoing elective coronary artery bypass gra ft surgery. Interventions Endothelin plasma content (fmol/mL) was measured in 50 patien ts undergoing coronary revascularization from various vascular compartments before surgery and at specific intervals up to 24 hours postoperatively. Measurements and Main Results: Myocardial endothelin gradient (coronary sin us - aorta) was calculated before cardiopulmonary bypass (CPB), at release of the aortic cross-clamp, immediately after CPB, and 0.5 hour after CPB. T he requirement for inotropic therapy and duration of patient stay in the in tensive care unit were determined. Systemic and pulmonary endothelin levels were increased by >80% immediately after CPB when compared with preoperati ve values and increased again by approximately 60% during the first 24 hour s postoperatively (p < 0.05). The myocardial endothelin gradient was revers ed after CPB, indicating myocardial production of endothelin (pre-CPB, -0.7 2 +/- 0.39 fmol/mL v 0.5 hour post-CPB, 0.60 +/- 0.49 fmol/mL; p < 0.05). L onger intensive care unit times (>28 hours) were associated with higher sys temic endothelin levels when compared with shorter times (<18 hours) (16.30 +/- 1.33 fmol/mL v 9.81 +/- 1.67 fmol/mL; p < 0.05). Patients with higher endothelin levels 6 hours postoperatively had greater inotropic requirement s during the intensive care unit period. Conclusion: Endothelin levels after CPB remained persistently increased for at least 24 hours after surgery and were associated with increased myocard ial production of endothelin. These results suggest that the increased endo thelin observed in the early postoperative period may contribute to a compl ex recovery from coronary artery bypass graft surgery. Copyright (C) 2000 b y W.B. Saunders Company.