Comparative Studies Of Inflammatory Response And Myocardial Injury Among Three Sorts Of Coronary Artery Bypass Graftings

There has been a resurgence of interest in off-pump coronary artery bypass (OPCAB) in the last decade, and the advantages associated with the use of this technique have been repeatedly emphasized. Because the morbidities of conventional coronary artery bypass grafting have been attributed to the use of cardiopulmonary bypass(CPB) and aortic crossclamping resulting in ischemia and reperfusion, so controversies still exist concerning the benefits of off-pump coronary artery bypass(OPCAB) when compared with conventional coronary artery bypass grafting(CCABG);these studies could not distinguish between myocardial injury induced by the cardiopulmonary bypass(CPB) and ischemia/reperfusion-related consequences, respectively. With the development of coronary artery bypass grafting, conventional coronary artery bypass grafting(CCABG) and off-pump coronary artery bypass(OPCAB) are connected with on-pump beating heart(On-PBH) which preserve native coronary blood flow, unload the heart and guarantee adequate organ perfusion. Meanwhile, it is possible for us to assess isolated CPB-induced and isolated ischemia/reperfusion induced effects on myocardial injury and inflammatory response with coronary artery disease. Therefore, this study was designed to not only assess the isolated CPB-induced effects on myocardial injury and inflammatory response with coronary artery disease by comparing off-pump coronary artery bypass (OPCAB) and on-pump beating heart(On-PBH), but also assess the isolated ischemia/reperfusion-induced effects on myocardial injury and inflammatory response with coronary artery disease by comparing conventional coronary artery bypass grafting(CCABG) and on-pump beating heart(On-PBH). It can definite operation indication.Method: 60 patients with normal EF and three vessels coronary artery disease (left main disease excluded) undergoing elective coronary artery bypass grafting were randomly divided into on-pump beating heart coronary artery bypass grafting group (On-PBH,20 cases), off-pump coronary artery bypass group (OPCAB,20 cases) and conventional coronary artery bypass grafting(CCABG,20 cases). Blood samples were collected from central vein to assay interleukin-6(IL-6), interleukin-8(IL-8), tumor necrosis factor-α(TNF-α), MB isoenzyme of creatine kinase(CK-MB) and troponin I(cTnI) before operation, immediately after reperfusion with the left internal mammary artery graft(CCABG group except)and 4,24,as well as 48 hours after operation, and all clinical data of the patients were recorded accordingly.Results: There was no significant difference in clinical outcomes between the OPCAB group and the On-PBH group; the operating time was longer and blood loss in 24 hours was greater for the On-PBH group; there was no postoperative mortality or major complication in either group. There are two cases of atrial fibrillation and one case of renal failure in the CCABG group which compared with the On-PBH group; After operation, the contents of IL-6, IL-8 and TNF-αwere higher in three groups than those before operation, and the contents of CK-MB and cTnI which showed little change in OPCAB group in postoperative period were significantly higher in the others. when compared with the OPCAB group, there was significant elevation in the levels of IL-6, IL-8, and TNF-αimmediately after the operations and they remained significantly elevated 4 hours after the operation in the On-PBH group, where significantly higher CK-MB and cTnI levels were found from left internal mammary artery - left anterior descending branch flow release onwards to 24h postoperatively. when compared with the On-PBH group, there was significant elevation in the levels of IL-6, IL-8, CK-MB and cTnI 4 hours after the operation in the On-PBH group, where IL-8 and cTnI levels remained significantly elevated 24h postoperatively.Conclusion: Off-pump coronary artery bypass revealed less myocardial injury and inflammatory reaction than on-pump beating heart coronary artery bypass,and these findings implicate that cardiopulmonary bypass affects the myocardium and inflammatory reaction. It seems that the modification of different cardioplegic techniques without elimination of cardiopulmonary bypass may not be helpful in abolishing the body's inflammatory response. On-pump beating heart coronary artery bypass revealed less myocardial injury between the conventional coronary artery bypass grafting and on-pump beating heart coronary artery bypass,and these findings implicate that ischemia/reperfusion-related consequences can affect the myocardium. The technique of on-pump beating heart coronary artery bypass (On-PBH) will be an acceptable trade-off between conventional coronary artery bypass grafting (CCABG) with cardioplegic arrest and off-pump coronary artery bypass(OPCAB) in selected high-risk patient.