Prediction Of The Severity Of Coronary Artery Lesions In Stable Coronary Artery Disease By Multi-parameter Imaging Of Speckle Tracking AFI

Background: In clinical routine transthoracic echocardiography,it carries great subjectivity to identify ischemic myocardium through visually observing segmental wall motion abnormality,and cannot predict the degree of coronary artery lesion in patients of coronary artery disease with normal wall motion.It was demonstrated that speckle tracking automated functional imaging(AFI)technology can significantly improve the sensitivity of the identification of myocardial ischemia or necrosis.The aim of this study was to explore the value of multiple myocardial function parameters generated by speckle tracking AFI technology in predicting the scope and extent of coronary artery lesions in patients with stable coronary artery disease(SCAD).Methods: In this study,from May 2018 to November 2019,a total of 188 patients with newly diagnosed stable coronary artery disease(SCAD)and underwent coronary angiography were finally included(excluding a history of myocardial infarction or revascularization therapy,acute coronary syndrome,cardiomyopathy,heart failure,valvular disease or other serious heart diseases,poor image quality and arrhythmia).According to the number of primary coronary arteries(including left main LM,left anterior descending artery LAD,left circumflex artery LCX,and right coronary artery RCA)stenosis branches(SCAD coronary stenosis was defined as the stenosis of main coronary lumen diameter ≥ 50%),these patients were divided into four groups: the control group for non-significant coronary lesion group(40 cases),SCAD1 for single-vessel lesion group(32 cases),SCAD2 for two-vessel lesion group(19 cases),SCAD3 for severe lesion group(including left main and three-vessel lesion,a total of 97 cases).All patients needed to complete routine transthoracic echocardiography before coronary angiography.At the same time,we stored standard apical three-view dynamic images and left ventricular outflow tract systolic blood flow spectrum.Left ventricular ejection fraction(LVEF)was measured by the biplane Simpson’s method.The speckle tracking AFI technology was applicated to quickly analyze left ventricular global longitudinal strain(GLS),post-systolic index(PSI),peak strain dispersion(PSD)and myocardial work(MW)related parameters(including global myocardial work index GWI,global constructive work GCW,global wasted work GWW,and global myocardial work efficiency GWE).According to the classification of the perfusion regions of three primary coronary arteries in left ventricular 17-segment model recommended by the American Heart Association,territorial longitudinal strain(TLS)and territorial PSI(TPSI)of each region were calculated.The degree of coronary artery lesions in each perfusion region was quantified by Gensini score method.Results: In the above four groups,LVEF and AFI parameters(including GLS,PSI,GWI,GCW and GWE)were statistically different(all P <0.001),while PSD and GWW were not(P > 0.05).When the control patients were compared with all SCAD patients,all the above parameters were statistically different except GWW(all P<0.05).With the increase of the number of coronary lesions,the absolute values of LVEF,GLS,GWI,GCW,and GWE in the SCAD3 group were significantly lower than those in the SCAD2,SCAD1 and the control groups(all P <0.05),while the PSI values in the SCAD3 group were obviously higher than the other three groups(P<0.01).The best cut-off values for predicting severe lesions in the four groups were:LVEF was 59.5%(AUC 0.677,95% CI 0.600–0.754,P <0.001),PSI was 10.27%(AUC 0.715,95% CI 0.641–0.788,P <0.001),GWI was 1683 mm Hg%(AUC 0.725,95% CI 0.653–0.796,P <0.001),GCW was 1938 mm Hg%(AUC 0.731,95% CI0.660–0.801,P <0.001),GWE was 91.5%(AUC 0.726,95% CI 0.655–0.797,P<0.001),GLS was-18.0%(AUC 0.813,95% CI 0.753–0.874,P <0.001),with sensitivity of 53.6%,70.1%,53.6%,51.5%,54.6%,and 64.9%,with specificity of80.2%,68.1%,82.4%,83.5%,81.3%,and 84.6%,respectively.When multiple parameters of GLS,PSI,GWI,GCW,and GWE were integrated with LVEF,the comprehensive AUC in the prediction of severe lesions was increased to 0.820(95%CI 0.761-0.880,P <0.001).Among all the parameters,the absolute value of GLS had the highest correlation with the total Gensini score,showing a significant negative correlation(r =-0.66,P <0.001).To identify the degree of coronary stenosis in each perfusion region ≥50%,the cut-off values of regional parameters were: the TLS of LAD region was-19.71%(AUC 0.812,P <0.001)and the TPSI was 12.07%(AUC0.678,P <0.001),the TLS of LCX region was-18.30%(AUC 0.716,P <0.001)and the TPSI was 10.63%(AUC 0.628,P <0.01),the TLS of RCA region was-17.70%(AUC 0.801,P <0.001)and the TPSI was 7.45%(AUC 0.627,P <0.01).Conclusion: Speckle tracking AFI can provide multi-parameter information to assist routine echocardiography in rapid evaluation of left ventricular myocardial function,and accurately identify stable coronary artery disease patients with severe coronary artery lesions at rest.Furthermore,the technology can also recognize significant stenosis of coronary arteries in each perfusion region to a certain extent.Combining multiple AFI parameters with LVEF can remarkably improve the diagnostic performance of conventional parameters.