浅低温心脏不停跳心内直视手术对心肌保护作用的研究

Effect of beating heart surgery with mild hypothermia on myocardial protection during cardiopulmonary bypass

目的 评价浅低温心脏不停跳心内直视手术对心肌保护作用的效果。方法 房间隔缺损 (ASD)、肺动脉瓣狭窄 (PS)和室间隔缺损 (VSD)患者共 4 8例 ,随机分为实验组和对照组。实验组在浅低温 (31～ 34℃ )体外循环、心脏跳动状态下手术 ;对照组在冷晶体停跳、中度低温 (2 8～ 30℃ )体外循环下手术。分别在术前及术后 2、6、2 4小时采集血标本 ,检测血清肌酸激酶同工酶 (CPK- MB)、超氧化物歧化酶 (SOD)活性和丙二醛 (MDA )、心肌钙蛋白 I(c Tn I)含量 ;分别在心内操作开始和结束时剪取小块右房组织 ,电镜观察心肌超微结构变化 ,并测定线粒体横截面积 ;同时观察术中体外循环情况 (体外循环时间、阻断时间 )。结果 1实验组较对照组的体外循环时间短 (P<0 .0 1) ,阻断时间长 (P<0 .0 5 )。2实验组较对照组术后 CPK- MB活性低 ,SOD活性高 ,MDA、c Tn I含量低。3心内操作完毕后 ,实验组较对照组心肌超微结构变化小 ,线粒体肿胀轻。结论 浅低温心脏不停跳手术对心肌具有更好的保护作用。

Objective To evaluate the effect of myocardial protection on beating heart with mild hypothermia cardiopulmonary bypass(CPB).Methods 48 patients with cardial diseases were randomly divided into two groups: experimental group(n=24),received surgery on beating heart with mild hypothermia(31℃～34℃) CPB,control group(n=24),received operation on arrested heart with moderate hypothermia(28℃～30℃) CPB.Blood samples were taken from artery.Then assess the activity of creatine phosphokinase-MB(CPK-MB),superoxide dismutase(SOD),and the content of malondiaehyde(MDA),cardiac troponin I(cTnI).The myocardial tissues were taken from right atrium for observing ultrastructural changes and measuring the area of the mitochondria.In the mean time,recorded the indexes of CPB.Results The activity of CPK-MB and the level of MDA,cTnI in experimental group were lower than those in control group,however the activity of SOD in experimental group was higher.The myocardial ultra structural changes were significant in control group.The CPB time of experimental group was shorter than that of control group(P<0.01),however the occlusion time was longer in experimental group (P<0.05).Conclusions The effect of myocardial protection on beating heart with mild hypothermia CPB was better than that on arrested heart with moderate hypothermia CPB.