停跳和不停跳行心脏直视手术对心肌保护作用的对比研究

Experimental study of myocardial protective effect of cardiac arrest versus beating heart during open heart surgery

目的 :探讨浅低温体外循环 ( CPB)下温血停搏液持续灌注和不停跳行心内直视手术对心肌的保护作用。方法 :18只同种健康山羊采用单盲法随机分为冷晶体间断灌注组 ( 组 ) ,温血停搏液持续灌注组 ( 组 ) ,不停跳组 ( 组 ) 3组 ,每组 6只 ;分别在 CPB的不同时刻测定心肌组织丙二醛 ( MDA)含量及静脉血心钠素( ANP)含量 ,并切取心肌组织在电镜下观察超微结构的改变。结果 : 组 MDA和 ANP在 CPB期间逐渐升高 ,恢复正常灌注后升高更明显 ; 组、 组 MDA和 ANP虽也有所升高 ,但较 组低 ,且恢复正常灌注后无升高趋势。心肌超微结构也显示 组改变明显 ,而 组、 组则基本不变。结论 :温血停搏液持续灌注和不停跳行心内直视手术可有效避免心肌的缺血和再灌注损伤 ,有良好的心肌保护作用。

Objective:To investigate the myocardial protective effects of beating heart versus heart arrest in goats undergoing open heart surgery with cardiopulmonary bypass (CPB).Methods:Eighteen healthy and homologous goats were randomly divided into three groups:groupⅠ(n=6),with intermittent cold crystalloid cardioplegia;groupⅡ(n=6),with continuous warm blood cardioplegia;group Ⅲ(n=6),with beating heart. Animals in groupⅡ and group Ⅲ were operated with mild hypothermic CPB.The changes in malondialdehyde (MDA) in the myocardium of the right ventricles and atrial natriuretic peptide (ANP) in venous blood were measured respectively.The myocardial tissues were examined for ultrastructural changes.Results:In group Ⅰ, contents of MDA and ANP rose significantly during CPB,especially when blood was reperfused routinely.While in group Ⅱ and group Ⅲ,the levels were lower than those in group Ⅰ at the same time points.There was no difference in the values between group Ⅱ and group Ⅲ.Ultrastructural changes were distinctly seen in group Ⅰ,while they were mild in group Ⅱ and group Ⅲ.Conclusion:Continuous warm blood cardioplegia to keep the heart beating during operation can prevent ischemiareperfusion injury and protect heart better.