| Objectiv:To investigate the protective effect of myocardial ischemicpostconditioning on myocardial ischemia/reperfusion injury in patients undergoing open heart surgery with cardiopulmonary bypass.Methods:Thirty patients(including 14 cases of mitral valve replacement,10 cases of atrial defect repair,4 cases of ventricular defect re-pair,1 case of ruptured aortic sinus aneurysm,1 case of Ebstien malfo-rmation correction)whose cardiac function(NYHA)grade II-III,aged 21-73 years old,underwent cardiac surgery with cardiopulmonary bypass for the first time in the Second Hospital of Hebei Medical University from September 2018 to February 2019 were selected and randomly divided into experimental group(n=15)andcontrol group(n=15).Experimental group: Myocardial ischemic postconditioning was performed before the opening of ascending aorta(open ascending aorta for 15 seconds,then clamp ascending aorta for 15 seconds for one cycle and repeat three cycles).Control group: Opening ascending aorta routinely.Blood samples were taken at 4 time points including the begining of operation(T1),12 hours(T2),24 hours(T3)and 48 hours(T4)after opening ascending aorta to measure the N-terminal brain natriuretic peptide precursor(NT-proBNP),creatine kinase isoenzyme(CK-MB)and cardiac troponin(cTnI).The cardiopulmonary bypass time,aortic blockade time,auxiliary circulation time and cardiac resuscitation rate were recorded.Postoperative positive inotropic drug scores(dopamine * 1 + dobutamine * 1 + milrinone * 15 + adrenaline * 100 norepinephrine * 100)was recorded as well.Results:1.There was no significant difference in gender,age,weight,preoperative cardiac function grade and ejection fraction between the two groups(P > 0.05).2.There was no significant difference in cardiopulmonary bypass time,aortic occlusion time and auxiliary circulation time between the two groups(P > 0.05).3.The rate of spontaneous recovery of heart rhythm after aortic opening was 93% in the experimental group and 75% in the control group.The rate of spontaneous recovery of heart rhythm in the experimental group was higher than that in the control group(P < 0.05).4.Postoperative positive inotropic drug scores were 283.53(+90.39)in the experimental group and 426.46(+151.57)in the control group.Positive inotropic drug scores in the experimental group were lower than those in the control group 24 hours after operation(P < 0.05).5.The results of N-terminal brain natriuretic peptide precursor(NT-proBNP)determination showed that the concentration of NT-proBNP in plasma of the two groups was within the normal range at T1 time point,and there was no significant difference between the two groups(P > 0.05).The plasma NT-proBNP levels at other times were higher than those at T1 in the two groups(P < 0.01).At the time points of T2,T3 and T4,plasma NT-proBNP concentration in the experimental group was lower than that in the control group,and there was significant difference between the two groups(P < 0.05 or P < 0.01).6.The results of plasma CK-MB concentration determination showed that the plasma CK-MB concentration of the two groups was within the normal range at T1,and there was no significant difference between the two groups(P > 0.05).The plasma CK-MB levels at T2,T3 and T4 of the two groups were higher than those at T1,and there was a significant difference between the two groups(P < 0.01).At the time points of T2 and T3,the plasma CK-MB concentration of the patients in the experimental group was lower than that of the patients in the control group,and there was significant difference between the two groups(P < 0.05 or P < 0.01).At T4 time point,the mean concentration of the experimental group was lower than that of the control group,but there was no statistical significance(P > 0.05).7.The results of plasma troponin I(cTnI)concentration determination showed that the plasma cTnI concentration of the two groups was within the normal range at T1,and there was no significant difference between the two groups(P > 0.05).The concentration of cTnI in plasma of the two groups at T2,T3 and T4 was higher than that of T1,and there was a significant difference between the two groups(P < 0.01).At the time points of T2,T3 and T4,the plasma concentration of cTnI in the experimental group was lower than that in the control group,and the difference between the two groups was statistically significant(P < 0.05 or P < 0.01).Conclusions:Ischemic postconditioning can reduce the concentration of NT-proBNP,CK-MB and cTnI in plasma,alleviate myocardial ische-mia/reperfusion injury,thereby significantly alleviating the damage of m-yocardial cells and tissues,and has good myocardial protection for pati-ents undergoing cardiac surgery under cardiopulmonary bypass. |
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