无创性心肌声学造影评价急性心肌梗死再灌注后冠脉微循环的实验研究

Experimental study of coronary microcirculation perfusion by noninvasive myocardial contrast echocardiography in reperfused acute myocardial infarction

目的:应用经静脉心肌声学造影(MCE)评价急性心肌梗死血管再通后的心肌微循环灌注情况。方法:30只中华小型猪,通过心导管介入法阻断前降支(LAD)120min,再灌注180min。在LAD闭塞及开通后分别行MCE,测定再灌注前后缺血心肌节段和正常心肌节段的视频强度值及心肌充盈缺损面积,计算无复流与危险区心肌面积比值(NRA/RA)。进行心肌病理染色,计算NRA/RA。结果:LAD开通后TIMI血流均为3级。再灌注180min后,缺血心肌节段的视频强度较闭塞时有所增加(P<0.01),但仍明显低于正常心肌(P<0.01),可见充盈缺损区。MCE和病理染色测定的NRA/RA分别为39.68±23.06%和31.07±14.25%,结果无显著性差异(P>0.05),相关系数r=0.715。结论:MCE可作为一种准确、无创评价心肌微循环灌注的有效方法。

Objective：To explore the change of myocardial microcirculation perfusion after epicardial coronary artery reopened in acute myocardial infarction （AMI） using intravenous intermittent triggered myocardial contrast echocardiography（MCE）.Metbods：Thirty juvenile pigs were used to create AMI model by placing a dilated balloon on the proximal of left anterior descending artery （LAD）.IAD was reopened by loosening the balloon after 120 minutes of occlusion. The reperfusion was lasted for 180 minutes.Intermittent triggered MCE was performed shortly after occlusion and 180 minutes after reperfusion.The video intensity （VI） of isehemic and normal myocardial segment was calculated with Q-lab software,which can reflect the segmental microvascular blood flow.The myocardial perfusion defects after occlusion was measured as risk area （RA） and that after 180 minutes of reperfusion was measured as no-reflow area （NRA）.The NRA/RA were calculated and compared with that by pathological staining method.Results：Twenty-seven pigs had been finished the whole study protocol. The thrombolysis in myocardial infarction（TIMI） grades was all Ⅲ after LAD reopened.Satisfied myocardial contrast imaging was obtained in 22 pigs （81.48%）.After 180 minutes of reperfusion,the Ⅵ of ischemic segment increased significantly compared with that after occlusion （P〈0.01）.But it was still lower than that of normal segment （P〈0.01）.The perfusion defects decreased but still existed in some pigs.The NRA/RA by MCE and pathological staining was 39.68±23.06% and 31.07±14.25% respectively and there was no significant difference（P〉0.05）.The correlation coefficient of the two methods was 0.715.Conclusion：Intermittent triggered MCE can reveal the myocardial mierocirculation noninvasively and effectively.