Left Ventricular Pressure Strain-Loop Technique To Assess Left Ventricular Systolic Function In Patients With Ischemia With Non-Obstructive Coronary Artery Disease

Background: Ischaemic coronary artery disease with non-obstructive coronary artery disease(INOCA)is defined as the presence of symptoms and objective evidence of myocardial ischemia without obstructive coronary artery stenosis on coronary angiography.This kind of disease is not benign.When there is microvascular dysfunction(CMD),the incidence of adverse cardiovascular events(MACE)will be greatly increased,and the prognosis is poor.Due to the large differences in clinical manifestations and the complex and diverse pathological mechanisms,it is very important to diagnose INOCA early and correctly to identify CMD,and to choose appropriate treatment methods according to different types.In recent years,left ventricular press-strain loop technique(LV-PSL)has become a new method to evaluate myocardial function,which uses non-invasive myocardial work(MW)parameters to evaluate the performance of left ventricular function.Objective: In this study,LV-PSL was used to evaluate left ventricular myocardial function in INOCA patients,and combined with transthoracic coronary flow imaging(TTDE)under regianoxan stress to evaluate coronary microvascular dysfunction,to explore the diagnostic value of LV-PSL in evaluating left ventricular systolic function of CMD in INOCA patients.Methods:A total of 43 patients with angina pectoris and no coronary artery stenosis was found by CAG or CCTA examination in our hospital from December 2021 to February 2023 were selected as the experimental group,and 30 age-matched healthy people without angina or myocardial ischemia symptoms were selected as the control group.The gender,weight,blood pressure and other data of the subjects were recorded,and the conventional echocardiographic parameters,MW parameters,GLS and PSD were obtained.The differences between the two groups were compared.In INOCA group,transthoracic coronary flow imaging(TTDE)was performed under stress,and MW parameters,GLS and PSD were obtained after stress.According to the results of coronary flow velocity reserve(CFVR)measured by TTDE,25 patients with CFVR < 2.0 in INOCA group were defined as case group A,and 18 patients with CFVR > 2.0 in INOCA group were defined as case group B.The correlation between the difference of MW parameters before and after load and CFVR was analyzed,and the receiver operating characteristic curve was established to analyze the diagnostic value of △GWI,△GCW,△GWW,and △GWE for CMD.Results:1.Compared with the control group,INOCA group showed significantly decreased GWI,GCW and GWE,increased GWW,decreased absolute GLS and increased PSD(p < 0.05).Pearson correlation analysis showed that GLS was negatively correlated with GWW(r=-0.534,p<0.01),and positively correlated with GWI,GCW,and GWE(r=0.657,0.617,0.521,p < 0.01).(2)the results of ROC curve of myocardial work showed that the area under the curve(AUC)of GWI,GCW,GWE and GLS were 0.73,0.68,0.81 and 0.87,respectively.The sensitivity of GWE was better than that of GLS,but its specificity was lower,and the overall diagnostic efficiency was slightly lower than that of GLS.(3)There were significant differences in △GWI,△GCW,△GWW,△GWE,△GLS and △PSD before and after INOCA load.△GWI,△GCW,△GWE,and △GLS were positively correlated with CFVR,while △GWW and △PSD were negatively correlated with CFVR.(4)The ROC curve of myocardial work before and after stress showed that the AUC of △GWI,△GCW,△GWE and △GLS were 0.89,0.78,0.96 and 0.93,respectively,and △GWE was superior to △GLS in the diagnosis of CMD.Conclusions:(1)Compared with normal controls,GWI,GCW and GWE in INOCA patients were reduced,while GWW was increased.The MW parameter could identify the impairment of left ventricular systolic function in INOCA patients at an early stage,and was well correlated with GLS,showing good diagnostic efficacy and providing a new ultrasonic index for evaluating left ventricular function in INOCA patients.(2)LV-PSL combined with stress echocardiography showed that △GWI,△GCW,△GWE,△GWW had a good correlation with CFVR,and △GWE had a good sensitivity and specificity,indicating that patients had reduced coronary flow reserve through changes in left ventricular controlic function reserve.Early assessment of such patients could provide timely intervention.It is very important for clinical prognosis.