Stress strain ultrasound evaluation of the protective effect of ATP-PostC on the circumferential function of rabbit acute myocardial infarction after reperfusion / 中华超声影像学杂志

ABSTRACT

Objective:To explore the application of speckle tracking imaging (STI) stratification strain technique in the assessment of circumferential myocardial function and the myocardial protection of ATP-postconditioning (ATP-PostC) in a rabbit model of acute myocardial infarction.Methods:A total of 40 rabbits were randomly divided into 2 groups pure ischemia reperfusion group (IR group)and ATP-PostC group. STI images were recorded before and 45 min after occlusion of coronary artery, post low-dose dobutamine stress echocardiography, 60 and 120 min after reperfusion, respectively. The following parameters were obtained left ventricular ejection fraction(LVEF), heart rate (HR), endocardial circumferential systolic strain (CSsys-endo), mid-myocardial circumferential systolic strain (CSsys-mid) and epicardial circumferential systolic strain (CSsys-epi) at left ventricular short-axis level. At different time points after occlusion and reperfusion, 5 experimental rabbits were killed in each group for pathological examination.Results:①Forty-five min after coronary artery occlusion in both groups, the values of LVEF and HR were decreased( P<0.05), and the absolute values of CSsys-endo, CSsys-mid and CSsys-epi were significantly reduced( P<0.01). After LDDSE, the absolute values of CSsys-endo, CSsys-mid and CSsys-epi were increased, which were different from those after blockade( P<0.05). ②After reperfusion, the circumferential strains were not significantly different from those after blockade in IR group ( P>0.05). After blockade, the absolute values of circumferential strains were increased significantly in the ATP-PostC group compared with IR group( P<0.05). In the ATP-PostC group, the absolute values of CSsys-endo at different time points after reperfusion increased significantly compared with that after blockade ( P<0.05). The absolute values of CSsys-endo and CSsys-mid 120 min after reperfusion continued to increase significantly compared with those 60 min after reperfusion( P<0.05). ③Pathological examination After 60 min of blockade, there was no significant difference in myocardial infarction area between the IR group and the ATP-PostC group( P>0.05). The percentage of infarct areas at each time point of reperfusion in the ATP-PostC group was decreased compared with that after blockade( P<0.05). Compared with the IR group, the percentage of infarct area in the ATP-PostC group was smaller after 120 minutes of reperfusion and the difference was statistically significant ( P<0.05). Conclusions:The applications of STI stratification strain technique and LDDSE can assess left ventricular circumferential strains at each of myocardial layers before and after reperfusion in rabbit myocardial ischemia ATP-PostC model, identify and evaluate the function of viable myocardium, and exhibit the significant protective effects of ATP-PostC on myocardial reperfusion injury.