Multilayer strain and stress echocardiography can represent myocardial viability and MI model types after different ischemic durations in rabbits

Abstract

Abstract Background To investigate myocardial viability and MI model types using multilayer strain and stress echocardiography and evaluate the sensitive STI indicators of myocardial contractile function and viability. Methods Fifty-four rabbits were randomly divided into the 60-min, 90-min, and 120-min coronary artery occlusion groups. Blood collections and speckle tracking echocardiography (STE) were performed at baseline, after ligation, and after low-dose dobutamine stress echocardiography (LDDSE). The ratio of infarcted myocardium to viable myocardium was calculated using Evans Blue-TTC. Results After ligation, the ventricular global endocardial longitudinal strain (GSLsys-endo), global myocardial longitudinal strain (GSLsys-mid), and global epicardial longitudinal strain (GSLsys-epi) decreased in the three groups (P < 0.05); longitudinal strain of endocardium (SLsys-endo), longitudinal strain of myocardium (SLsys-mid), and longitudinal strain of epicardium (SLsys-epi) decreased in the affected segments (P < 0.05). After LDDSE, the absolute values of the above indicators in the 60-min and 90-min groups and GSLsys-endo, GSLsys-mid, GSLsys-epi in the 120-min group were significantly increased (P < 0.05). The absolute values of SLsys-endo, SLsys-mid and SLsys-epi in the ischemic segments increased (P < 0.05) in all groups. In the infarcted segments, the absolute values of SLsys-mid and SLsys-epi in 60-min group, SLsys-epi in 90-min group and none in 120-min group increased (P < 0.05). After coronary artery occlusion, malondialdehyde and tumor necrosis factor-α levels were increased, and superoxide dismutase was decreased (P < 0.05). The myocardial infarction area percentage was higher in the 120-min group (40.5%±2.8%), followed by the 90-min (29.3%±3.6%) and 60-min (16.8%±3.2%) groups (P < 0.05). The mortality of the 120-min group was higher than in the two other groups (22.2% vs. 5.6% and 11.1%, P < 0.05). Conclusions Multilayer strain and stress echocardiography can evaluate myocardial viability and MI model types in rabbits after different ischemic durations and provide insights into the selection of an appropriate STI indicators and animal model for future reperfusion experiments.