Study On The Mechanism Of Ischemic Mitral Regurgitation And The Mechanism Of Ischemic Mitral Regurgitation After Annuloplasty With Echocardiography

BackgroundOf the outward shift of papillary muscle, leaflet configuration and the dilation of annulus, one or all these factors are the main reason for ischemic mitral regurgitation (MR) , which influence the balance of closing force and tethering of mitral valve and lead to incompetence of leaflet closure. There is no report on relationships between leaflet configurations and ischemic MR ( Paper One). We hypothesized that surgical mitral annuloplasty for ischemic mitral regurgitation, displacing the posterior annulus anteriorly, can potentially augment posterior leaflet (PML) tethering, leading to persistent MR afterwards. Relationships between leaflet configurations and persistent ischemic MR before and after the annuloplasty were investigated to further understand the mechanism of ischemic MR before and after the surgery ( Paper Two).MethodsIn 31 consecutive patients with surgical annuloplasty for ischemic MR and 20 controls. Posterior and apical displacement of the leaflet coaptation relative to the anterior annulus or the;line connecting annuli in the left ventricular ( LV) long axis view, the anterior leaflet (AML) and PML tethering angles relative to the annular line, LV volume, LV ejection fraction and LV D/L, Mitral annular area, and the MR grade were quantified before and early after the surgery byechocardiography.ResultsCompared with normal controls, patients with ischemic MR showed significant change in LV ejection fraction, LV volume, D/L and the annular area. Significant increases in the apical displacement of the coaptation (p < 0. 01) , wosening in both AML and PML excursion ( p <0. 01) , resulted in systolic mitral valve tenting. Six of 31 (19% ) patients showed persistent MR despite an-nuloplasty. Compared to patients without persistent MR, those with the MR showed no improvement in the LV ejection fraction, and systolic volume, similar reduction in the annular area, significant increase in posterior displacement of the coaptation ( p <0. 01) , no improvement in AML tethering and greater worsening in PML tethering ( p <0. 01). While increase in apical and posterior displacement of the coaptation with increased AML tethering were the independent determinants of MR before annuloplasty (r=0.76, p<0.01) , increased PML tethering was the independent determinants afterwards (r=0.86, p<0.01).ConclusionWhile combination of both leaflets tethering is the major determinant of ischemic MR before surgical annuloplasty, both leaflets tethering but with predominant contribution from posterior leaflet tethering is related to persistent ischemic MR after the annuloplasty.