| In recent years, preliminary study on cardiac troponin(cTn) showed that cardiac troponin I (cTnI) was a novel specific antigen of heart. One of cTn subunit is cTnI which has unique sequence in gene. The molecule weight of cTnI is 22500 dolton. In human, cTnI is merely located in atrial myocytes and ventricular myocytes. There is only one kind of TnI and there are no differnees in fetus, neonate, and adult. When myocytes degenerate and become necrotic because of ischemia or oxygen deficit, cTnI can pass through cell membrane and be released into blood. Beause of low molecular weight of cTnI and continuous releasing from degenerated myocardial cells, cTnI appears very early after onset of acute myocardial infarction (AMI) and maintains high concentration for a long time. Compared with serum enzyme creatine kinase isoenzyme (CK-MB), the most extensive used biochemical index, cml is more specific to diagnose myocardial injury. As for its sensitivity, especially early sensitivity to diagnose myocardial injury keeps controversial, and great differences were reported in China and foreign countries. Researches for cTnI usually lay in AMI, studies in cardiovascular surgery field were relatively few. Myocardial cell injury probably has existed in patients with cardiovascular diseases, myocardial ischemia and reperfusion injury also lead to myocardial cell injury during cardiopulmonary bypass, perioperative infarction may occur after cardiac surgery. All those changes contribute to changes of cTnI Levels in peripheral blood. Therefore, it is of great significance to study changes of serum cTnI levels and evaluate myocardial injury during perioperative period in heart Surgery. It is not completely clearthat the ru1e of cTnI re1easing during perioperative period in Heart Surgery.Coronary artery bypass graft (CABG) is a most effective method to treatcoronary heart disease. Myocardia1 injury a1ways occurs a1though there are manydifferent myocardia1 preservation methods during CABG. No methods of myocardia1preservation are definitely superior to others. No research has been conductedto study on myocardia1 injury during CABG with different myocardia1 preservationmethods by way of changes of serum cTnI in China.In this study, we investigated the ru1e of cTnI re1easing and ana1yzed theextents of myocardia1 injury between different heart surgery according to theresu1ts of serum cTnI concentration detected from b1ood of patients with certainheart diseases during perioperation. We a1so compared changes of serum cTn1concentration with changes of CK--MB activity in the process of perioperation.We eva1uated the extents of myocardia1 injury in different strategies formyocardial management during CABG.The research work and resu1ts were divided into two parts as fo1lows.Part 1 Studies on the Dynareic8 of S.rm cTnI Lev.I8 Dur ingPer iOP.rat ion of Heart Surg6ryWe random1y chosed 35 patients who underwent cardiac Surgery. These patientswere divided into three groups according to different diseases which thesepatiens had suffering from. Group I (n=17), coronary artery disease (CABG) group.Group II (n=10) rheumatic heart disease (DVR) group; GroupIII (n=8), congenita1 heartdisease (ASD) group. Serum cTnI concentration and CK--us activity were detectedbefore surgery, at 2,,, 8,,, 24,*, 48,,, 72th hour and 7th day after aortic unc1amping.We compared changes of serum cTnI concentrations with changes of creatine kinaseCK--MB activities and eva1uated the extents of myocardia1 injury in differentcardiac surgery.R.8u lt0n the condi tion that no perioperative infarct ion occured, the maximum serumconcentration of cTnI appeared at 8,, hours after aortic unc1amping in the threegroups and returned to normal 1imit...
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