Résumé
ObjectiveTo investigate the role of ischemic postconditioning on lung ischemic/reperfusion injury induced by cardiopulmonary bypass (CPB) in combined mitral and aortic valve replacement,and evaluate the effects of different protocol of ischemic postconditioning,and analyze its possible mechanisms.Methods24 patients diagnosed as rheumatic mitral and aortic valve disease with or without tricuspid valve disease were randomly divided into 3 groups (8 in each):Control group( group A),patients undergoing routine cardiac surgery; Postconditioning group Ⅰ (group B ),patients undergoing routine cardiac surgery and ischemic postconditioning by occlusion of the pulmonary artery of five cycles of 15 s ischemia and 15 s repeffusion before the pulmonary artery totally restoring peffusion; Postconditioning group Ⅱ (group C),patients undergoing routine cardiac surgery and ischemic postconditioning by occlusion of the pulmonary artery of five cycles of 30 s ischemia and 30 s repeffusion before the pulmonary artery totally restoring perfusion.The Oxygenation Index (OI) was measured at pre -operation and 1 h,2 h,3 h,6 h and 12 h after terminating CPB.The plasma contents of MDA were detected by Enzyme-linked Immunosorbent Assay at pre -operation,1 h,3 h,6 h and 12 h after terminating CPB.ResultsCompared with group A and C,OI in group B significantly increased at 1 h,2 h,3 h,6 h after terminating CPB (283.25 ±56.47 vs 384.76 ±29.17 vs 310.50 ±65.71,265.75 ±58.78 vs 381.75 ±29.67 vs 310.50 ±48.17,283.75 ±73.15 vs389.74±39.34 vs 317.87 ±78.41,310.37 ±52.00 vs 401.62 ±4 2.89 vs 337.25 ± 64.06,all P ＜0.05),and the plasma contents of MDA in group B reduced at 1 h,3 h,6 h,12 h after terminating CPB (4.64±0.63 vs 3.88 ±0.20 vs 4.38 ±0.41,5.75±0.49 vs 4.44 ±0.34 vs 5.28 ±0.76,4.42±0.31vs 3.77 ± 0.40 vs 4.35 ± 0.54,3.74 ± 0.31 vs 3.19 ± 0.17 vs 3.64 ± 0.24,all P ＜ 0.05 ), However,there were no significant differences in OI and MDA between group C and A (all P ＞0.05 ).Conclusions Ischemic postconditioning by occlusion of the pulmonary artery of 5 cycles of 15 s ischemia and 15 s reperfusion attenuates lung oxygenation function injury induced by CPB in double valves replacement,and it is possibly mediated by reducing MDA produced by lipid peroxidation.However,ischemic postconditioning by occlusion of the pulmonary artery of 5 cycles of 30 s ischemia and 30 s repeffusion may not have significant protective effect for lung oxygenation function injury induced by CPB in double valves replacement.