Background: Recent data has emerged regarding improved mitral regurgitation(MR) reduction with third generation MitraClip-XTR, comparable to second-generation MitraClip-NT. There is limited data on morphological predictors of successful MR reduction after MitraClip-XTR. We sought to examine the impact of pre-procedural mitral annular dimensions on MR reduction after MitraClip-XTR repair and identify echocardiographic predictors of suboptimal MR reduction.
Methods: From 3/2018 to 8/2019, 107 patients(age 78.9±6.7 years; 40.2% female) with symptomatic >moderate MR(46.7% primary MR; 53.3% secondary MR) underwent MitraClip-XTR repair. Annular geometry was evaluated before and after edge-to-edge(E2E) repair using 2D- and 3D-transesophageal echocardiography. Predictors of suboptimal reduction defined as ³moderate MR on transthoracic echocardiography at discharge were identified. Mean follow-up was 12.5+6.3 months, and Mitral Valve Academic Research Consortium-2 outcomes were reported.
Results: Technical success was achieved in 99(93.4%), with 22.8% mortality at 1-year. Suboptimal reduction seen in 28(26.2%), was associated with higher 1-year mortality [OR=4.5(1.5-14.1)]. Suboptimal reduction was associated with effective regurgitant orifice area(EROA) [OR=46.4(2.9-741.4)], left atrial volume(LAVol) [OR=1.008(1.001-1.015)], and greater end-systolic mitral annular dimensions including 2D-anteroposterior diameter(APd) [OR=1.09(1.003-1.12)], 3D-APd [OR=1.10(1.005-1.21)], 2D-intercommisural diameter(ICd) [OR=1.16(1.06-1.27)] and 3D-ICd [OR=1.15(1.04-1.26)]. Independent predictors of suboptimal reduction were vena-contracta width(VCW) [OR=1.33(1.01-1.74)] and end-systolic projected-area [OR=1.003(1.001-1.004)]. On receiver operating curve analysis, end-systolic 2D-APd>40.5mm, 3D-APd>40.5mm, 2D-ICd>38.5mm, 3D-ICd>40.5mm and projected-area>1250mm2 were the most predictive thresholds for suboptimal reduction. We found an escalating risk with increasing number of 3D-TEE predictors, and in 3D-APd>40.5mm, 3D-ICd>40.5mm and projected-area>1250mm2, the risk of suboptimal reduction increases by 16.7-fold.
Conclusions: Suboptimal MR reduction significantly impacts cumulative survival after MitraClip-XTR therapy, and is associated with markers of MR severity like EROA, VCW and LAVol, and degree of baseline annular dilation. Our proposed thresholds for pre-procedural annular dimensions may serve as guidance for improved patient selection in MitraClip-XTR repair.