Multiparametric evalutation of percutaneous mitral valve repair (MitraClip) after 6 months

BACKGROUNDS MitraClip (MC) therapy is now established as a secure, feasible treatment option for patients with severe mitral regurgitation (MR) at high surgical risk. The efficacy of the percutaneous approach, especially in patients with functional disease, has been evaluated in a large number of studies, but the endpoints used to establish the success of this procedure over the surgical ones were based on unreliable, less standadizable measures.  PURPOSE This study sought to evaluate the efficacy of MC therapy in terms of new functional outcomes, comparing data related to degenerative mitral regurgitation (DMR) and functional mitral regurgitation (FMR).  METHODS Between October 2010 and November 2018, 100 consecutive patients with severe MR and not eligible for surgical mitral valve repair were assessed before MC implant using echocardiogram, BNP assay, cardiopulmonary exercise test (CPET) with non-invasive measurement of cardiac output (CO) with inert gas rebreathing technique, at baseline and after 6 months. RESULTS MC implant rate was 95%. Immediate success with reduction of MR to 642+ was observed in 80% of cases and 76% after 6 months. In both FMR and DMR, a significant reduction of MR from baseline was observed (p<0.001). NYHA class showed a significant improvement over six months in both groups. Significant left ventricular (LV) remodeling was observed only in DMR group (LV End-diastolic Volume index was 70\ub114 mL at baseline, 59\ub114 mL at 6 months, p<0.001). Systolic pulmonary pressure values were significantly reduced from baseline in both population (PAPs was 44\ub112 mmHg at baseline, 40\ub18 mmHg at 6 months, p=0.047 in FMR and 42\ub112 mmHg at baseline, 38\ub18 mmHg , p=0.029 in DMR). In DMR LV ejection fraction reduced significantly from 63\ub19% to 59\ub18, as expected. CO and stroke volume (SV) increased significantly at rest only in FMR patients (CO 3.1\ub10.9 L/min at baseline, 3.4\ub10.9 L/min at 6 months, p=0.006; SV 45\ub115 mL/min at baseline, 52\ub114 mL/min at 6 months, p=<0.003), while during exercise in FMR CO improved from 5.6\ub11.8 L/min to 6.2\ub11.7, p=0.023 and SV from 56\ub123 ml/min to 63\ub121, p=0.007 and AV O2 difference reduced from 17.1\ub14.3ml/100ml to 15.3\ub13.9, p=0.019. On the other hand, the population with degenerative disease did not present any improvement. Peak oxygen consumption showed an improving trend, not significant. Heart rate did not show significant changes both at rest and during exercise. No differences were found in BNP levels or VE/VCO2 slope.  CONCLUSIONS MC reduced MR and produced a significant LV reverse remodelling over 6 months in DMR population treated. Functional outcomes, as the improvement of CO and SV at rest and during exercise with an improvement in NYHA class, proved the efficacy of the percutaneous mitral valve repair in patients with FMR