Recurrence of Functional Versus Organic Mitral Regurgitation After Transcatheter Mitral Valve Repair: Implications from Three-Dimensional Echocardiographic Analysis of Mitral Valve Geometry and Left Ventricular Dilation for a Point of No Return

Abstract

MitraClip implantation has become the standard transcatheter mitral valve repair (TMVR) technique for severe mitral regurgitation (MR). However, approximately one third of patients have poor outcomes, with MR recurrence at follow-up. The aim of this study was to investigate whether quantitative analysis of mitral valve (MV) geometry on three-dimensional (3D) echocardiography can identify geometric parameters associated with the recurrence of severe functional MR (FMR) versus organic MR (OMR) at 6-month follow-up after TMVR using the MitraClip. Sixty-one patients with severe FMR (n=45) or OMR (n=16) who underwent transesophageal 3D echocardiography before and 6months after TMVR were retrospectively analyzed. MV geometry was quantified using 3D echocardiography software. Vena contracta area (VCA) at 6-month follow-up was used to define two outcome groups: patients with good results with VCA<0.6cm2(MR<0.6) and those with MR recurrence with VCA≥0.6cm2(MR≥0.6). MR recurrence was found in 34% of all study patients (21 of 61). In patients with FMR, significant differences between MR<0.6 and MR≥0.6 were found at baseline for tenting index (1.13 vs 1.23, P=.004), tenting volume (2.8 vs 4.0ml, P=.04), indexed left ventricular (LV) end-diastolic volume (68.0 vs 99.9ml/m2, P=.001), and VCA (0.71 vs 1.00cm2, P=.003); no significant parameters of MR recurrence were found in patients with OMR. Multivariate analysis identified indexed LV end-diastolic volume as the strongest independent determinant of MR recurrence. Receiver operating characteristic analysis identified a tenting index of 1.185 (area under the curve 0.79) and indexed LV end-diastolic volume of 88ml/m2 (area under the curve 0.76) to best discriminate between MR<0.6 and MR≥0.6. MR recurrence after TMVR in patients with FMR is associated with advanced LV dilation and MV tenting before TMVR, which provides clinical implications for a point of no return beyond which progressive LV dilation with MV geometry dilation and tethering cannot be effectively prevented by TMVR. In contrast, no significant determinants of MR recurrence and progressive MV annular dilation could be identified in patients with OMR.