Acute Changes in Mitral Valve Geometry after Percutaneous Valve Repair
with MitraClip XTR by Three-Dimensional Echocardiography
Abstract
BACKGROUND. Mitral valve (MV) repair with MitraClip system is a safe
treatment option for high-risk patients with significant mitral
regurgitation (MR). We aimed to characterize, by three-dimensional
echocardiography (3D-E), changes occurring in MV after implantation of
third generation MitraClip XTR device, with specific reference to the
underlying MR mechanism (functional vs. degenerative, FMR vs DMR).
METHODS. We prospectively enrolled 59 patients, who underwent
intra-procedural 3D-E before and after device deployment. Three-D
datasets were analysed off-line, using a dedicated semiautomatic
software, to obtain parametric quantification of mitral anatomy.
RESULTS. Post-procedural MR of mild or lesser degree was achieved in 40
patients (68%), with no differences between FMR and DMR (p 0.9). After
MitraClip XTR implantation, the FMR group experienced an immediate
annular resizing, with reduction of antero-posterior diameter (p 0.024)
and sphericity index (p 0.017), next to a recovery of physiological
saddle-shape, defined by lower non-planar angle (p ≤0.001) and higher
annulus height to commissural width ratio (p ≤0.001). On the opposite,
the DMR group revealed a significant decrease of maximum annular
velocity (p 0.027), addressing a mechanic effect of the device
deployment. Finally, baseline anterior mitral leaflet angle was found as
the strongest independent predictor of acute procedural result (OR 0.91,
[CI 0.84-0.99], p = 0.030). CONCLUSIONS. MitraClip XTR implantation
acts in restoring the original mitral geometry, with distinctive effects
according to MR mechanism. Three-D parametric quantification of MV sheds
new light on changes occurring in the valvular apparatus, and helps
identifying possible new predictors of acute procedural success.