Quantitative evaluation of myocardial microvascular endothe lial dilatation by time-intensity curve with myocardial contrast echocardiography in dogs / 中华超声影像学杂志

ABSTRACT

Objective To investigate the changes of mi crovascular endothelial dilatation in stunned myocardium. Methods Thirteen healthy and adult mongrel dogs were randomly organized into two groups, group A (n=6) and group B (n=7). Each dog in group A and B underwent 15 min and 30 min acute ligation at left anterior descending coronary artery (LAD), respectively. Myocardial contrast echocardiography was implemented via intra-femoral vein bolus injection of C 3F 8-exposed sonicated dextrose albumin at different examining time.Peak-intensity (PI) and area under curve (AUC) were derived from time-intensity curve (TIC) after aortic root injection of acetylcholine (ACH) or nitroglycerin (NG),and then PI ratio (PIR) and AUC ratio (AUCR) of pre- to post-ACH or pre- to post- NG were calculated at each of the corresponding examining times. Myocardial endothelium-dependent relaxation (EDR) and non-EDR were analyzed at different examining times. Results ①At baseline (before LAD ligation), PI and AUC in group A and B increased considerably via aortic root injection of ACH and NG. ② After ACH injection,PIR in group A decreased sharply at 5,30 and 60 min, whose P values were less than 0.05 compared with baseline. And all these recovered completely at 120 min reperfusion. However,PIR in group B recovered slowly and reached finally to baseline at 150 min reperfusion. Meanwhile, the variation trends of AUCR in both group A and B were the same as those of PIR. Overall, the dynamic tendencies of PIR and AUCR in these two groups for post-NG at different examining times were much similar to those of post-ACH. ③ The decreased magnitudes of PIR and AUCR in group A and B after ACH injection were bigger than those of NG injection at 5,30 and 60 min reperfusion(P