Late Self-Apposition With One-Year Persisting Uncoverage of Malapposed Bioresorbable Polymeric Struts

Aims: To appraise the early effect of percutaneous mitral valve repair with the MitraClip system on myocardial function using real-time three-dimensional speckletracking echocardiography (3D-STE). Methods: Consecutive patients with moderate-to-severe or severe mitral regurgitation, undergoing mitral valve repair with the MitraClip system, were prospectively evaluated during the peri-procedural workout and follow-up. Left ventricular deformation was evaluated by a twodimensional and 3D speckle-tracking analysis. 3D-STE acquisitions were elaborated obtaining real-time 3D global longitudinal strain evaluation, and by appraising both volumetric and hemodynamic parameters (i.e. left ventricular end-diastolic volume, left ventricular endsystolic volume, left ventricular ejection fraction, cardiac output, and stroke volume). Results: In all, 30 patients were included. At 1-month followup, 3D-STE analysis revealed no changes in left ventricular end-diastolic volume (162.6±73.7 ml at baseline vs. 159.8±64.5 ml at 1-month follow-up; P=0.63) and a downward trend in left ventricular end-systolic volume (104.7±52.0 vs. 100.1±50.4 ml, respectively; P=0.06). Left ventricular ejection fraction did not significantly increase (38.1±11.3% at baseline vs. 39.4±11.0% at 1-month follow-up; P=0.20). No significant changes were reported in cardiac output (4.3±2.0 l/min at baseline vs. 4.0±1.5 l/min at follow-up; P=0.377) and in stroke volume (59.5±25.5 ml at baseline vs. 59.9±20.7 ml at follow-up; P=0.867). On the contrary, left ventricular deformation capability significantly improved, with the realtime 3D global longitudinal strain value changing from S9.8±4.1% at baseline to S11.0±4.4% at follow-up (P=0.018). Conclusions: Accurately assessing myocardial function by the use of 3D-STE, this study reported irrelevant early changes in left ventricular size, but a positive effect on left ventricular deformation capability following mitral valve repair with the MitraClip system. These preliminary results need to be confirmed in larger series and extended to longterm follow-up