Three-dimensional Echocardiography In Evaluation Of Ischemic Mitral Regurgitation, Mitral Annular Configuration And Its Influencing Factors

BackgroundIschemic mitral regurgitation(MR) usually occurs as a result of mitral annulus dilatation and papillary muscle displacement secondary to global left ventricle dysfunction and remodeling,with prognostic importance in patients with coronary artery disease.Although mitral annulopasty has been used commonly,the most appropriate treatment for ischemic MR remains controversial because of its complex underlying mechanism.We evaluated the mitral annulus with 3-dimensional echocardiography(3DE) to assess the annular remodeling and its dynamic change during cardiac cycle in ischemic MR,and analyzed 3-dimensional annular predictors related to ischemic MR with multivariate regression.Objective1.To evaluate the mitral annulus with 3DE in ischemic MR.2.To assess the annular remodeling and its dynamic change during cardiac cycle in patient with different LVEF and sites of MI.3.To investigate the best 3-dimensional annular predictor of ischemic MR.Methods3DE was performed in 45 patients with prior myocardial infarction(MI) or regional wall motion abnormality found in routine echocardiography,and in 26 healthy subjects(Control group).The imaging was analyzed offiine with TomTec 4D MV-Assessment software to measure the annular diameters(AP diameter,AL-PM diameter and commissural diameter),annular circumference,anterior and posterior annular length,annular area and non-planar angel(NPA).All parameters were standardized by body surface area.The dynamic changes during the cardiac cycle were calculated by diastolic value minus systolic value.3-dimensional annular predictors related to IMR were analyzed with multivariate regression.Results1,Patients were divided in 2 groups according to the degree of MR:No IMR group(MR≤2:n=21) and IMR group(MR≥2:n=24).The mitral annulus was significantly enlarged in the IMR group,all the 3 annular diameters,the annular circumference and MAA were increased compared with the other 2 groups.While in the No-IMR group,the dilation of mitral annulus was only found with AL-PM diameter and commissural diameter.The NPA was progressively increased in No-IMR group and IMR group(p＜0.01 between groups).During the cardiac cycle,the dynamic change of all the 3 diameters and the fraction of the mitral area change were lower in IMR group compared with the Control(p＜0.01),while there were no difference between No-IMR and Control.2,Patients were divided in 2 groups according to the position of MI: No-inferior MI group and Inferior MI group.The mitral annulus was significantly enlarged in Inferior MI group:all the 3 annular diameters,the annular circumference and MAA were increased compared with Control group.While in the No-inferior MI group,the dilation of mitral annulus was only found with ALPM diameter and commissural diameter.The NPA was increased in Inferior MI group compared with the Control(p＜0.01).During the cardiac cycle,the decrease in dynamic change of annular circumference was only found in Inferior MI group.3,Patients was divided in 2 groups according to the degree of LVEF:LVEF≥45%group and EF＜45%group.The mitral annulus was significantly enlarged in EF＜45%group,all the 3 annular diameters,the annular circumference and MAA were increased compared with the control.The NPA was progressively increased in LVEF≥45%group and EF＜45%group(p＜0.05 between groups).During the cardiac cycle,the dynamic change of commissural diameter,ALPM diameter,posterior annular length and annular circumference were lower in EF＜45%group.The fraction of the mitral area change were lower in EF＜45%group compared with the Control(p＜0.01) and LVEF≥45%group(p＜0.05).4,IMR was closely correlated with AALd,LVEF,MAAd,NPA,AAP,ALPM, CCd,MAA,especially NPA.By analysis of ROC curves,the cut-off value of NPA for diagnosing moderate MR was 158.05°;the sensitivity,specificity and accuracy of NPA were 91.7%,81.5%and 84.6%respectively.Conclusion1.In patients with IMR,the mitral annular remodeling was not only presented as the size enlargement but also the flattening of its special geometric shape and the decrease of its dynamic systolic function in cardiac cycle. 2.The 3DE parameters with practical meaning in ischemic MR included AALd, LVEF,MAAd,NPA,AAP,ALPM,CCd and MAA.3.The cut-off value of NPA for diagnosing moderate MR was 158.05°;the sensitivity,specificity and accuracy of NPA were 91.7%,81.5%and 84.6% respectively.4.3DE could be used to quantities the annular remodeling and its dynamic change during cardiac cycle;it would be helpful for us to understand the mechanism of ischemic MR and played a important role in evaluating the mitral annulus in ischemic MR.