心肌声学造影评价缺血后处理对犬顿抑心肌微血管内皮功能的保护作用

目的探讨心肌声学造影（myocardial contrast echocardiography，MCE）技术评价缺血后处理（ischemic postconditioning，IPC）对犬顿抑心肌冠状动脉微血管内皮功能保护作用的价值。方法14只健康成年杂种犬随机分成对照组和后处理组。对照组左冠状动脉前降支结扎15min，再灌注120min；后处理组结扎15min后，使用动脉夹，再灌注30S，缺血30S，反复3次，然后再灌注118min30S。分别于缺血和再灌注阶段行MCE检查。在不同时间观测点经主动脉根部注射乙酰胆碱（ACH），在注射前和注射后40-50s重复MCE，以注射ACH后与注射前时间一强度曲线参数峰值强度（PI）和曲线下面积（AUC）的比值PIr和AUCr作为观察指标。结果两组顿抑心肌的PI和AUC均小于正常心肌，后处理组比对照组更快恢复至正常水平，且在再灌注的不同时间点PI和AUC高于对照组。再灌注后两组顿抑心肌的PIr和AUCr均减低，并逐渐恢复，后处理组比对照组更快恢复至正常水平，且在再灌注的不同时间点PIr和AUCr高于对照组。结论顿抑心肌存在微血管内皮功能损害，血管内皮依赖性舒张功能减低，缺血后处理对顿抑心肌微血管内皮功能有保护作用，MCE能够定量评价IPC的保护作用。

Quantitative Evaluation of Ischemic Postconditioning Protective Effect on Myocardial Microvascular Endothelial Dilatation Using Myocardial Contrast Echocardiography

Objective To evaluate the protective effect of ischemic postconditioning(IPC)on myocardial microvascular endothelial dilatation via myocardial contrast echocardiography(MCE).Methods Fourteen anesthetized dogs were randomly divided into two groups:In the control group,the anterior descending coronary artery(LCA)was occluded for 15 minutes followed by 120 minutes reperfusion;In IPC group,LCA was occluded for 15 minutes,then three cycles of 30 seconds reperfusion followed by 30 seconds LCA re-occlusion were applied and then followed by 118 minutes and 30 seconds reperfusion.MCE parameters of time-intensity curve were measured before and after acetylcholine(ACH)injection.Results The peak intensity(PI),area under the curve(AUC)and endothelium-dependent relaxation(EDR)in myocardial stunning were significant decreased versus those in the normal myocardium,but were increased gradually with the prolonging reperfusion duration,and were recovered faster in IPC group than in the control group.Conclusions EDR in myocardial stunning was injuried.IPC had protective effect on myocardial EDR.MCE can evaluate the protective effect of IPC on myocardial EDR.