无创肢体缺血预处理对心脏换瓣术患者心肌的保护作用

Protection of noninvasive limb ischemic preconditioning on myocardium in patients undergoing heart valve surgery under cardiopulmonary bypass

目的:探讨无创肢体缺血预处理(noninvasive limb ischemic preconditioning,NIPC)对体外循环(cardiopulmonary bypass,CPB)下心脏瓣膜置换术患者围术期心肌保护的可能机制。方法:将择期CPB下行瓣膜置换术的风湿性心脏病患者32例随机分为对照组(n=16)和NIPC组(n=16)。NIPC组在麻醉诱导后立即用止血带先后阻断双上肢血流8min,复灌5min,反复3个循环;对照组不予缺血预处理。分别于麻醉诱导后即刻(T1)、主动脉阻断前5min(T2)、主动脉开放后30min(T3)、术后6h(T4)及24h(T5)经中心静脉取血测血浆心肌肌钙蛋白和肌酸激酶同功酶,分离血清测定降钙素基因相关肽(calcitonin gene related peptide,CGRP)和内皮素(endothelins-1,ET-1)含量。分别于上腔静脉插管和拔管时取部分右心耳组织观察病理结构。结果:两组在T4和T5的心肌肌钙蛋白和肌酸激酶同功酶水平均较同组其他时间点高,均在T5达到峰值;NIPC组的心肌肌钙蛋白和肌酸激酶同功酶水平在T4和T5均较对照组低(P<0.05)。NIPC组CGRP和ET-1含量在T2达峰值,对照组两者含量在T3达峰值;NIPC组CGRP峰值高于对照组(P<0.01),ET-1峰值低于对照组(P<0.01)。NIPC组CPB后心肌细胞和线粒体损伤较对照组轻。结论:无创肢体缺血预处理可能通过上调CGRP并抑制ET-1的上升,同时使CGRP和ET-1含量峰值提前,发挥心肌保护作用。

Objective To determine the mechanism of protective effect of noninvasive limb ischemic preconditioning （NIPC） on myocardium of patients with rheumatic heart disease undergoing heart valve surgery under cardiopulmonary bypass （CPB）.Methods A total of 32 patients with rheumatic heart disease undergoing heart valve surgeries under CPB were randomly divided into 2 groups： a control group（n=16）and an NIPC group（n=16）.Tourniguet was used for each patient in the NIPC group around both the upper extremities in turn,inflated for 8 min and deflated for 5 min for 3 cycles.After the anesthesia,the remaining procedures were the same as in the control group.Blood samples were collected from the central vein after the induction of anesthesia （T1）,5 min before aortic clamp （T2）,30 min after aortic opening （T3）,6 h after the operation （T4）,and 24 h after the operation （T5） to measure the concentration of cardiac troponin I and creatine kinase MB in the plasma and CGRP and ET-1 in the serum.Pathologic change of the right auricle of the heart tissue during the superior vena cave intubation and extubation was detected.Results The content of cardiac troponin I and creatine kinase MB at T4 and T5 in the 2 groups was higher than that of other time points in the same group,and it reached the peak at T5.Comparison of the content of cardiac troponin I and creatine kinase MB at T4 and T5 in the 2 groups showed significant difference,and that of the NIPC group was lower than the control group（P〈0.05）.CGRP and ET-1 contents reached the peak at T2 in the NIPC group and at T3 in the control group,but the peak of CGRP in the NIPC group was higher than that in the control group（P〈0.01）.The peak of ET-1 content in the NIPC group was lower than that in the control group（P〈0.01）.After the CPB,myocardial and mitochondrion impairment was lighter in the NIPC group than in the control group.Conclusion Noninvasive limb ischemic preconditioning can protect the myocardium through increasing CGRP,inhibiting ET-1,and advancing the peak of CGRP and ET-1.