停搏液单次及不同压力多次灌注对未成熟心肌保护的效果

Effects of Infusion Pressure of Cardioplegia on Immature Myocardium.

目的：探讨停搏液灌注压力对未成熟心肌灌注效果的影响。方法：３～４周龄幼兔３６只，随机均分为４组，Ｉ组为单次灌注，Ｉ～ＩＶ组为多次灌注。首次灌注压均为６０ｍｍＨｇ（１ｍｍＨｇ＝０．１３３ｋＰａ），Ｉ～ＩＶ组的重复灌注压分别为６０、４５、３０ｍｍＨｇ。离体心灌注模型在１５℃下缺血１２０分钟，按设计灌注Ｓｔ．ＴｈｏｍａｓＩ停搏液。观察冠状血管阻力（ＣＶＲ）、冠状动脉流量恢复率（ＣＦＲ）、心肌含水量和超微结构变化。结果：Ｉ组所有指标均优于Ｉ～ＩＶ组；Ｉ～ＩＶ组ＣＶＲ和心肌含水量随灌注压升高而增加，ＣＦＲ则逐渐降低；Ｉ组血管内皮细胞肿胀明显，管腔变窄。结论：停搏液单次灌注优于多次灌注；多次高压灌注可影响停搏液对未成熟心肌的灌注效果，可能与心肌的微血管损伤有关。

Objective:To examine the effects of infusion pressure of cardioplegia on immature myocardium.Method:Thirty six isolated ,Langendorff perfused rabbit working hearts(aged 3 4 weeks) were subjected to 120 minutes of ischemia at 15℃ with St.Thomas II cardioplegia.The animals were divided into four groups:group I with single infusion group II IV with multiple infusion.The volume of cardioplegia was 100ml/kg in all groups and the first infusion pressure was 60mm Hg,but for group II、III and IV,the subsequent infusion pressure were 60、45 and 30mm Hg,respectively.Cardioplegic infusion were repeated every 30 minutes.After 30 minutes reperfusion ,the myocardial water content,coronary flow recovery(CFR),coronary vascular resistence(CVR),ATP and CP content ,left ventricular systolic pressure(LVSP),CK and LDH leakage were measured and compared among the four groups.Results:All of these parameters except CK and LDH leakage were better in group I than in group II IV(P<0.05).During subsequent infusions ,CVR rose gradually with increase of infusion pressure of cardioplegia.In group II,myocardial water content and CVR were significantly increased and CFR、LVSP reduced markedly when compared with thoes in group IV.However the ATP and CP content、CK and LDH leakage had no significant differences among the different pressure groups.Conclusion:These results indicate that the single infusion method of cardioplegia at 15℃ may provide better myocardial protection than the multiple infusion method in immature myocardium and the high pressure infusion impairs the protective effect of cardioplegia on immature myocardium.This may be related to the microvascular damage of immature myocardium.