Evaluation Of Left Ventricular Systolic Function In Patients With Hypertension By Layer-specific Strain And Transmural Gradient

Background:Hypertension is one of the most common cardiovascular diseases at present.In recent years,its incidence has been increasing,seriously affecting people's quality of life and physical and mental health.The pathogenesis of hypertension is complicated,which is related to genetic factors,diet,spirit and neural mechanism.Hypertensive heart disease is one of the main causes of chronic heart failure.The adaptation of cardiomyocytes is crucial in the remodeling process.This pathophysiological process is difficult to be analyzed by conventional biomarkers or imaging methods such as ultrasound and magnetic resonance imaging.The quantitative evaluation of the local and global function of the left ventricular myocardium has been paid much attention to the imaging diagnosis,but the stratified analysis of the left ventricular myocardium function is still lack of in-depth research.The left ventricular myocardial fibers are divided into three layers:the inner layer is mainly longitudinal myocardium,the middle muscle is annular,and the outer myocardium is oblique.When the inner and outer myocardium contracts,the ventricles shorten,while the middle myocardium shrinks.Due to the unique structure of myocardial fibers and the different roles of each layer of myocardium in ventricular work,various pathological factors may have different effects on the function of each layer of myocardium,especially at different stages of disease development^[1].Hypertension is the most important risk factor for cardiovascular disease and kidney disease^[2].Accurate evaluation of left ventricular function in hypertensive patients is of great significance for clinical treatment.This study aims to apply layered strain technology combined with cross-wall order difference to quantitatively analyze the changes of systolic function in left ventricular,middle and outer myocardium of hypertensive patients,so as to detect the damage of each layer of myocardium at an early stage and provide reference for clinical intervention.Objective:To investigate the value of ultrasonic two-dimensional speckle tracking imaging?2D-STI?layer-specific strain and transmural gradient in evaluation of the systolic function of the left ventricular of patients with hypertension.Methods:Group A included 25 patients with hypertension and renal insufficiency who were admitted to our hospital from July 2017 to August 2018,Group B was 35 patients with hypertension without renal dysfunction,and 40 healthy volunteers served as the control group C.The 2D-STI technique was used to obtain the systolic peak longitudinal strain?LPS?of the left ventricle:the peak systolic longitudinal strain of endocardium(LPS_Endo),the peak systolic longitudinal strain of mid-cardium(LPS_Mid)and the peak systolic longitudinal strain of epicardium(LPS_Epi),and calculate the cross-wall between the various layers of the myocardium.The indexes such as the transmural gradient??LS?and the percentage of the transmural gradient??LS%?were calculated.Results:There was a gradient of LPS among the three layers in the three groups:LPS_Endo>LPS_Mid>LPS_Epi.Compared with LPS_Mid,LPS_Endo and LPS_Mid in the three groups,the difference was statistically significant?P<0.05?.There was significant difference between LPS_Mid and LPS_Epi in group B and C?P<0.05?,but there was no significant difference in group A?P>0.05?.Compared with group B and group C,LPS_Endo?LPS_Mid and LPS_Epi were decreased in group A,and the difference was statistically significant?P<0.05?,Group B Compared with C,only the difference in LPS_Endo was statistically significant?P<0.05?.?LS were compared between the three groups of A,Band C,but there was no significant difference?P>0.05?.Compared with group B and C,the Endo-Mid?LS%and Mid-Epi?LS%of group A increased?P<0.05?.Compared with group C,the Endo-Mid?LS%of group B increased?P<0.05?,while Mid-Epi?LS%was no significant difference.Conclusions:The layer-specific strain technique can quantitatively evaluate the changes of systolic function in the left ventricular myocardium of hypertensive patients.?LS%may have better sensitivity than?LS in the inhibition of systolic function in the left ventricular myocardium.Provide more reference for the evaluation of left ventricular systolic function.