Effect of ischemic postconditioning on myocardial injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass

Abstract

Objective To evaluate the effect of ischemic postconditioning on myocardial injury in the patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB). Methods Thirty patients of both sexes, aged 21-59 yr, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ(New York Heart Association Ⅱor Ⅲ), with left ventricular ejection fraction ≥ 40%, scheduled for elective cardiac valve replacement under CPB, were divided into 2 groups (n=15 each) using a random number table: control group (C group) and ischemic postconditioning group (P group). In group P, ischemic postconditioning was induced by 3 cycles of 30 s aortic unclamping followed by 30 s cross-clamping starting from 5 min before complete opening of the ascending aorta.After induction of anesthesia and before operation (T1), at 1 h after opening of the ascending aorta (T2), at the end of operation (T3), and at 12, 24 and 48 h after opening of the ascending aorta (T4-6), blood samples were taken from the radial artery for determination of plasma concentrations of heart-type fatty acid-binding protein (H-FABP), ischemia-modified albumin (IMA), and cardiac troponin I (cTnI). Myocardial specimens in the right auricle were obtained at T2, and the pathological changes were examined using an optical microscope. Results The concentrations of plasma cTnI at T2-6 and H-FABP and IMA at T2-5 were significantly higher than those at T1 in the two groups (P<0.05). Compared with group C, the concentrations of plasma cTnI at T2-6, H-FABP at T2-4, and IMA at T2, 3 were significantly decreased (P<0.05), and the pathological changes of myocardial tissues were significantly reduced in group P. Conclusion Ischemic postconditioning can reduce myocardial injury in the patients undergoing cardiac valve replacement under CPB. Key words: Ischemic postconditioning; Myocardial reperfusion injury; Cardiopulmonary bypass