Clinical Study On Myocardial Protection Of HTK Solution In Elderly Patients With Long-term Open-heart Surgery

Objective:To investigate the myocardial protective effect of HTK cardioplegia solution(Constant solution)on elderly patients(aged over 65 years)undergoing open-heart surgery under long-term cardiopulmonary bypass(CPB time over 2 hours and to preliminarily analyze its mechanism.Methods:159 cases of open-heart surgery in Cardiovascular Surgery Department of the First Affiliated Hospital of Soochow University from January 2016 to March 2018 were selected.The minimum age of all cases was 65 years old and the cardiopulmonary bypass time was more than 120 minutes.They were randomly divided into H(HTK)group and T(St.Thomas)group according to the types of cardioplegia.Although there is difference between the baseline data of the two groups,After PSM(propensity score matching,PSM),47 pairs of patients were successfully matched(n=47).There were no significant differences in basic clinical data such as age,sex ratio,weight,cardiothoracic ratio,preoperative left ventricular EF value,incidence of chronic complications,incidence of atrial fibrillation,aortic blocking time during cardiopulmonary bypass,total time of cardiopulmonary bypass,and surgical methods between the two groups(P>0.05).Myocardial arrest was induced by perfusion of HTK solution in groupH,while myocardial arrest was induced by perfusion of St.Thomas cardioplegia solution(crystal blood ratio 1:4)in group T.Serum cardiac troponin I(cTnI)and serum creatine kinase isoenzymes(CKMB)were measured and recorded at three different time points(preoperative,first day and third day after operation).Total cardiopulmonary bypass time,ascending aorta blocking time,cardiac assist time(aortic opening to cardiac resuscitation time)and automatic cardiac resuscitation were recorded in all two groups.Cardiac defibrillation and rebound,incidence of arrhythmia after operation,EF value of left ventricle after operation,time of using vasoactive drugs after operation,time of mechanical ventilation support after operation,time of stay in intensive care unit(ICU),incidence of heart failure,respiratory failure and renal failure after operation were analyzed and recorded.Results:There was no significant difference in the incidence of arrhythmia,EF value of left ventricle,heart failure,renal failure and respiratory failure between the two groups(P>0.05),but the days of using vasoactive drugs,days of ventilator support and ICU stay in group H were significantly shorter than those in group T(P<0.05).The rate of automatic cardiac resuscitation and defibrillation in group H were significantly higher than that in group T,but the time of auxiliary circulation was longer,the difference was significant(P<0.05).The baseline data of the two groups after PSM matched equally,there was no significant difference in the auxiliary circulation time,the incidence of arrhythmia after operation,EF value after operation,the incidence of heart failure,renal failure and respiratory failure after operation(P>0.05);indeed,the days of using vasoactive drugs,the days of ventilator-assisted support and ICU stay in group H were significantly less than those in group T,and the difference was still significant.There was significant difference(P<0.05).The cardiac resuscitation in group H was still better than that in group T,and the rate of automatic cardiac resuscitation was significantly higher and the rate of defibrillation resuscitation was significantly lower(P<0.05).Before PSM,the serum CKMB and cTnI indexes of the two groups were compared in three periods before operation,the first day after operation and the third day after operation.Without matched analysis,there was significant difference in CKMB indexes between the two groups before operation(P<0.05),but there was no significant difference in cTnI serum values between the two groups(P>0.05).On the first day after operation,the serum CKMB and cTnI indexes of the two groups increased significantly and were significantly higher than those before operation.But on the first day.The increase of myocardial enzymes in group H was significantly lower than that in group T(P<0.05).On the third day after operation,the CKMB values of the two groups had fallen back to the preoperative level,but the CKMB values of group H were significantly lower than those of group T(P<0.05).Although the serum cTnI values of the two groups did not fall back to the preoperative level on the third day after operation,the CKMB values of group H were significantly lower than those of group T(P<0.05).The serum CKMB and cTnI levels of the two groups before and after PSM were basically the same(P<0.05);the serum CKMB and cTnI levels of the two groups were significantly increased on the first day after operation,but the elevated values of group H were significantly lower than those of group T.The difference was significant.On the third day after operation,the serum myocardial enzymes of the two groups decreased,and the serum CKMB levels of group H were significantly lower than those of group T(P<0.05),but on the third day after operation,the serum CKMB levels of The cTnI index of group A was significantly lower than that of group T(P<0.05),and the difference was statistically significant.Conclusion:HTK solution has a protective effect on myocardial injury in elderly patients undergoing cardiac surgery under cardiopulmonary bypass for a long time.Compared with the traditional St.Thomas cardioplegia,HTK solution can reduce the myocardial damage caused by ischemia reperfusion injury better,improve the rate of cardiac automatic rebound and shorten the recovery time of patients.