Objective: To observe the dynamic changes of tumor necrosis factor-alpha(TNF-alpha) and endothelin (ET-1) during perioperative period in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) and to investigate their pathological significance so as to bring up feasible measure to increase therapeutic effect.
Methods: Blood samples of 32 patients undergoing CABG with CPB were drawn before operation, induction period of anaesthesia, after aortic crossclamping and declamping, by the end of surgery, and 2 hours, 8 hours, and 24 hours after surgery. The plasma TNF-alpha and ET-1 were measured by radioimmunoassay (RIA).
Results: (1) The plasma TNF-alpha level increased markedly after aortic crossclamping (18.3 ng/L +/- 3.4 ng/L vs 12.1 ng/L +/- 2.0 ng/L, P < 0.05) and went up to the peak value(22.4 ng/L +/- 3.6 ng/L) after aortic declamping, and then decreased. However, till 24 hours after operation, the TNF-alpha concentration maintained at a level higher than that before surgery (18.5 ng/L +/- 4.1 ng/L vs 12.1 ng/L +/- 2.0 ng/L, P < 0.05. After aortic declamping, during reperfusion of the lungs the TNF-alpha level was significantly higher than that after aortic crossclamping and before declamping (22.4 ng/L +/- 3.6 ng/L vs 18.3 ng/L +/- 3.4 ng/L P < 0.05). (2) The plasma ET-1 increased significantly after aortic crossclamping (146 ng/L +/- 20 ng/L vs 97 ng/L +/- 14 ng/L, P < 0.05) and went down after aortic declamping. Two hours after surgery, the plasma ET-1 increased again and reached the second height (134 ng/L +/- 19 ng/L), and then went down again and decreased to 92 ng/L +/- 18 ng/L 24 h after operation.
Conclusion: (1) Attenuation of inflammatory reactions mediated by TNF-alpha should be considered an important strategy for myocardial and lung protection. (2) During the perioperative period of CABG the plasma ET-1 level shows two peaks, occurring respectively after aortic crossclamping and 2 h after surgery, which may result from operation itself and ischemia-reperfusion injury.