The Protective Effect Of HTK Cardioplegia On Immature Myocardium In Cardiopulmonary Bypass

Objective:The vast majority of the experimental efforts have involved mature heart models, but there are reasons to believe that myo- cardial ischemia in the immature heart may differ in some ways from that in the mature heart, and therefore, different strategies for myocardial preservation during ischemia might be desirable. The purpose of this study focus primarily on comparing the myocardial protective effect of Histidine-Tryptophan- Ketoglutarate (HTK) cardioplegia with cold crystalloid cardioplegia in infant open heart surgery to determine whether HTK cardioplegia is better than cold crystalloid cardioplegia.Methods:Twenty infants with Tetralogy of Fallot were randomized into two groups. In group A (n =10) was carried out with HTK cardioplegia, and group B with cold crystalloid cardioplegia (St.Thomas'â…¡, STH). After anesthesia, cardiopulmonary bypass was instituted, and then the ascending aorta was clamped. And then cardioplegic solution was instilled. HTK cardioplegia was instilled about forty milliliter per kilogram and one time was enough. STH cardioplegia was instilled about fifteen milliliter per kilogram the first time, after that every thirty minutes was done about eight milliliter per kilogram until aortic crossclamp was removed. There was no significant difference between group A and group B in cardiopulmonary bypass (CPB) and operation. Serum levels of cardiac troponin I (cTnI),creatine kinase(CK),creatine kinase MB (CK-MB) and lactate dehydrogenase (LDH) were measured after anesthesia, and at 12h,24h,48h,7d after referfusion. Fatty acid binding proteins (FABPs) was measured at 2hand 6h after referfusion. The following clinical parameters were recorded, such as the auto-beating rate, the incidence of arrhythmia, the dose of inotropic drugs, mechanical ventilating time, etc.Results:Before ischemia, cardiac function and leakage of myocardial enzyme were comparable in two groups with no significant difference (p>0.05). After ischemia auto-beating ratio and the dose of adrenalin in group A were significantly lower than those in group B. CK, CK-MB, cTnI and HFABP leakage in group A were significantly lower than those in group B (p<0.05). LDH leakage: there was no difference between before ischemia and after ischemia.Conclusions:1 The experimental results indicate that in HTK group the repeating perfusion is unnecessary. So we can regard it is convenient to using in the myocardial preservation of immature heart.2 After ischemia auto-beating ratio and the dose of adrenalin in group A were significantly lower than those in group B. These results show that HTK cardioplegia can improve the heart-function recovering speed.3 CK, CK-MB, cTnI and HFABP leakage in group A were significantly lower than those in group B, which suggest that HTK cardioplegia can alleviate the ischemia-reperfusion injury to immature myocardium.