Three-dimensional Echocardiographic Speckle Tracking Technique Was Used To Evaluate Left Ventricular Function In Transient Myocardial Ischemia

Study on the left ventricular function of the transient myocardial ischemia animal model established via percutaneous interventional method by echocardiographyObjective:Using percutaneous interventional method balloon occlusion of the coronary artery to establish the model of transient myocardial ischemia.The left ventricular function was evaluated by two-dimensional conventional echocardiography.Methods:Twenty-six healthy Chinese experimental mini-pigs were randomly divided into sham operation group(n = 6)and transient myocardial ischemic group(n = 20).Sham operation group was only placed in the balloon but not open,transient ischemic group balloon occlusion left coronary anterior descending artery to the distant position of the first diagonal branch.After 15min,balloon was removed.Using and echocardiographic changes to confirm model successively established.Echocardiography and ECG were performed to check the dynamic changes of cardiac electrical activity and left ventricular function,and the echocardiographic parameters included:left atrial diameter(LAD),left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),interventricular septum(IVS),left ventricular posterior wall(LVPW),left ventricular ejection fraction(LVEF),stroke volume(SV),wall motion score index(WMSI)and mitral flow E peak,A peak velocity,tissue Doppler E'.Echocardiography was performed at baseline,15min,30min,90min,Id,3d and 7d.Systolic blood pressure(SBP),diastolic blood pressure(DBP),left ventricular end diastolic pressure(LVEDP),left ventricular end-systolic velocity(LVEDP),LV + dp/dtmax and LV-dp/dtmax were measured to determine the left ventricular pressure changing during the modeling process.The blood samples were collected at the same time.Five animals were sacrificed at 90min,1d,3d and 7d,respectively to conduct cardiac histological examination.Results:All 26 animals were successfully housed in the balloon.In sham operation group,coronary angiography showed normal coronary flow before and after the operation;transient myocardial ischemic group showed that the LAD blood flow were completely interrupted after balloon occlusion.ECG chest leads showed ST segment elevation;Echocardiography indicated the anteroseptal and anterior wall abnormalities.The LVESP and LV + dp/dtmax were increased at the time of balloon removal in the ischemic group(all,P<0.05),while the SBP,DBP,LVEDP,LV-dp/dtmax had no significant change(all,P>0.05).In the model group,4 cases of transient myocardial ischemia with malignant arrhythmia,the heart of the general and microscopic showed that the cardiomyocytes have different degrees of necrosis,and 2 cases without malignant arrhythmia had focal myocardial necrosis;and the myocardial injury markers of these 6 cases also increased multiple.Echocardiography showed that LVEF and SV significantly decreased(all,P<0.05),while WMSI increased(P<0.05)at the time of 15min and 30min;But all parameters were recovered and had no significant difference at the time of 90min,Id,3d,7d compared with the baseline(all,P>0.05).The pathological results showed that from 90min to 7d,the myocardium lesion area was gradually changed from ischemia,necrosis,inflammatory cells infiltration to myocardial fibrosis.There were no obvious abnormalities in echocardiography and pathology in sham operation group.Conclusions:Transient myocardial ischemia with or without malignant arrhythmia can lead to myocardial necrosis,but the necrosis range varied widely.The diagnostic window of transient myocardial ischemia for traditional echocardiography is narrow.For early diagnosis,it has important value,but for late diagnosis of ischemia,conventional echocardiography is limited.Evaluation of left ventricular systolic function in transient myocardial ischemia model by three-dimensional speckle tracking echocardiographyObjective:Routine examination often failed to find abnormalities in transient myocardial ischemic patients result fromAnd this delay may lead to some patients with exacerbations or even sudden death.The diagnostic window of transient myocardial ischemic is narrow.For early diagnosis,echocardiography has important value,but for late diagnosis of ischemia,conventional echocardiography is limited.Delayed admittance and alleviated ischemic symptoms caused it difficult to diagnosis.Diagnostic delay may lead to some patients with exacerbations or even sudden death.In this study,we used percutaneous intervention to establish transient myocardial ischemia model.Three-dimensional speckle tracking echocardiography(3D-STE)was used to evaluate the left ventricular function at different time points of model animals.Aim to investigate the diagnostic value of 3D-STE in transient myocardial ischemia.Methods:Twenty-six healthy Chinese experimental mini-pigs were randomly divided into sham operation group(n = 6)and transient myocardial ischemic group(n = 20).The model of transient myocardial ischemia was established by balloon occlusion of the left anterior descending coronary artery for 15 minutes.Electrocardiogram and echocardiography were used to evaluate whether the model was established successfully.The sham operation group was only implanted balloon without opening it.Echocardiography was performed at baseline,early stage of ischemic[balloon occlusion immediately(st),15 min,30 min],late stage(90 min,1 d,3d and 7 d).Left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),stroke volume(SV),left ventricular ejection fraction(LVEF)and 3D-STE parameters global longitudinal strain(GLS),global circumferential strain(GCS),global radial strain(GRS)and global area strain(GAS)were analyzed.At the same time,the left ventricular catheter was used to measure the left ventricular pressure before and after balloon occlusion.The blood samples were collected for the detection of myocardial injury markers.Five animals were sacrificed at the time of the late ischemic phase,and the myocardial specimens were stained with Evan's blue and TTC to observe the myocardial infarction and ischemia.Pearson correlation analysis was used to estimate the correlation between the range of ischemic and the 3D-STE parameters.For the parameters of LVEF,SV,GLS,GS,GRS receiver operating characteristic(ROC)curves were obtained and the optimal values with the greatest total sensitivity and specificity in diagnose transient myocardium ischemia.Results:Two groups of animals were successfully implanted into the balloon.Sham operation group before and after the balloon occlusion,coronary angiography showed normal coronary blood flow,ECG and echocardiography were no significant changes.In the transient myocardial ischemia group,20 animals were successful modeling.There was no significant difference of all parameters at each time of the ultrasound examination in the sham operation group(P>0.05).There were significant differences in LVESV,SV,GLS,GCS,GAS and GRS between the two groups(P<0.01).Compared with baseline,LVESV,GLS,GAS,GRS and GCS were decreased in early ischemic stage(P<0.001),LVESV,GRS and GCS back to the baseline level in late phase,but GLS,GAS were still reduced(P<0.01).Among the three time points of early stage or the four time points of late stage,there was no significant difference between each two points(all,P>0.05).When compared the 30min time point with the 90min,LVESV decreased while SV,GCS,GRS,GLS,GAS increased(all,P<0.001),especially GLS and GAS(all,P<0.01).Pearson correlation analysis showed that GLS and GAS had better correlation with myocardial ischemia and infarct size(P<0.001)at every time point in the late ischemic stage.(90min:AUC was 0.993 and 0.988,respectively;cut-off value was-18.0 and-26.5,respectively.1d:AUC was 0.979 and 0.979,respectively;cut-off value was-18.5 and-26.5,respectively.3d:AUC was 0.992 and 0.950,respectively;cut-off value was-18.5 and-26.5,respectively.7d:AUC was 0.950 and 0.900,respectively;AUC,cut-off value was-18.5 and-29.5,respectively).Conclusion:3D-STE can not only confirm the early stage of transient myocardial ischemia,but also GLS and GAS,not GCS or GRS have good diagnostic value in the late stage of ischemia.Study on layer-specific strain in complex CAD with non-ST-segment elevation acute coronary syndromeObjectives:To evaluate the three layers of left ventricle(LV)deformation by layer-specific strain in non-ST-segment elevation acute coronary syndrome(NSTE-ACS)patients with and without complex coronary artery disease(CAD).Methods:139 patients undergoing coronary angiography due to suspected NSTE-ACS were prospectively enrolled.Global longitudinal strain(GLS),territorial longitudinal strain(TLS),global circumferential strain(GCS)and territorial circumferential strain(TCS)of the three layers of LV wall were assessed by layer-specific two-dimensional(2D)speckle tracking echocardiography(STE)based on the perfusion territories of the three major coronary arteries in an 18-segment model of LV.Syntax score(SS)was used for predicting the severity of coronary lesions in complex CAD patients.Results:78 had complex CAD,32 had 1-/2-vessel disease and 29 had no significant coronary stenosis confirmed by coronary angiography.According to SS value,78 complex CAD were subdivided into three groups,group SS1(SS<22,n=24),group SS2(SS 23-32,n=26)and group SS3(SS?33,n=28).Compared to the other two groups,patients with complex CAD had worse function in all 3 myocardial layers assessed by GLS,TLS,GCS and TCS(all,P<0.01).Endocardial GLS and TLS were most affected.The absolute differences between endocardial and epicardial GLS and TLS were lower in patients with complex CAD than in those without(all,P<0.001).Endocardial GLS and TLS were closely correlated with SS value(r=-0.751 and-0.753,respectively;P<0.001).By receiver-operating characteristic curve analysis,endocardial GLS and TLS demonstrated the higher area under curve,showing better diagnostic accuracy than other parameters(all,P<0.05).Conclusions:Layer-specific strains,particularly endocardial GLS and TLS measurement might enable a non-invasive method to identify complex CAD and predict the severity of coronary lesions in NSTE-ACS patients.