Assessment Of Left Ventricular Myocardial Layer-specific Strain In Aortic Stenosis Patients In Perioperative Period By Using Two-dimensional Speckle Tracking Imaging

Objective: Quantitative analysis of the left ventricular Myocardial Layer-specific strain in high-gradient severe Aortic Stenosis(AS)patients in perioperative period with normal left ventricular ejection fraction(LVEF)by using two-dimensional speckle tracking imaging(2D-STI),and to explore the changes in left ventricular systolic function.Methods: A group of twenty high-gradient severe AS patients who performed AVR with LVEF≥50% were enrolled in this study.They were all selected from Second Hospital Affiliated to Dalian Medical University Cardiac Surgery Department between November 2015 and December 2017.They were divided into two groups: Preoperative of AVR group and Postoperative of AVR group(7 ± 3 days).Thirty healthy adult volunteers were selected as the control group at the same time.Using GE Vivid E9 ultrasound diagnostic instrument,M5 S probe was selected.The frequency of 1.5 ~4.5MHz,more than 40 frames per second frame rate of image capture were set up and images were saved.Then the Echo PAC software was used to analyze the image data,Two-dimensional echocardiography(2DE)and 2D-STI parameters include:1.2DE parameters: left ventricular end-diastolic diameter(LVEDd),left ventricular end-systolic diameter(LVESd),inter ventricular septum thickness diastolic(IVSTd),left ventricular posterior wall thickness diastolic(LVPWTd),aortic valvular mean pressure gradient(MPG),aortic maximum velocity(Vmax),the left ventricular ejection fraction(LVEF)(Simpson).2.2D-STI parameters: left ventricular systolic global longitudinal peak strain(GLS),systolic global circumferential peak strain(GCS)and Longitudinal systolic peak strain in the endocardium,mid-cardium and epicardium(LSendo、LSmid、LSepi)and circumferential systolic peak strain in the endocardium,mid-cardium and epicardium(CSendo、CSmid、CSepi)of the left ventricle.The absolute value of each strain parameters were analyzed.Results:1.2DE parameters: Compared with the control group,IVSTd,LVPWTd,aortic valvular MPG,aortic valvular Vmax increased in the preoperative of AVR group,the differences were statistically significant(P<0.05);Compared with the preoperative of AVR group,aortic valvular MPG,aortic valvular Vmax decreased in postoperative of AVR group,the differences were statistically significant(P<0.05).2.2D-STI parameters:(1)Compared with the control group,the absolute values of GLS and LSendo、LSmid、LSepi of three sections decreased in the preoperative of AVR group(P<0.05);And also,the absolute value of GCS decreased(P<0.05),but there were no significant differences in absolute value of CSendo at mitral valve and papillary muscle levels in the preoperative of AVR group(P>0.05).The absolute values of CSmid,CSepi at the mitral valve and papillary muscle levels and the absolute values of CSendo,CSmid and CSepi at apical level were decreased(P<0.05).(2)Compared with the preoperative group,the absolute values of GLS and LSendo、LSmid、LSepi of three sections decreased in postoperative of AVR group(P<0.05).The absolute values of GCS and CSendo 、 CSmid 、 CSepi at the mitral valve and papillary muscle levels decreased(P<0.05);however,the absolute values of CSendo,CSmid and CSepi increased in the apex level(P<0.05),but the increase of the absolute value of CSendo had a more significant statistical difference in postoperative of AVR group(P<0.05).Conclusions: 2D-STI can be used to quantitatively evaluate the global and layer-specific strain of the left ventricular myocardium in patients of high-gradient severe AS with normal LVEF.The three levels of myocardial strain is a sensitive index to evaluate left ventricular systolic function in patients of severe AS with normal LVEF.