• MitraClip
• mitral annulus geometry changes
• mitral valve quantification
• tridimensional trans-oesophageal echocardiography

Background. MitraClip procedure is a treatment option in patients with symptomatic mitral regurgitation (MR) and prohibitive surgical risk. Echocardiographic evaluation of mitral valve (MV) is of paramount importance for the correct identification of patient eligibility and procedural success. Our aim is to assess the acute effect of device implantation on mitral annular geometric parameters still little explored with the use of three-dimensional (3D) trans-oesophageal echocardiography (TEE) and its relationship with residual MR at discharge.
Methods. We recorded 67 consecutive patients undergoing percutaneous MV repair with MitraClip between January 2016 and November 2019 at San Donato Hospital. Patients eligibility was evaluated according to the EVEREST criteria and current guidelines. Four groups were identified on the base of MR aetiology: 22 were degenerative (DMR), 19 ischemic functional (IFMR), 19 non-ischemic functional (NIFMR) and 7 atrial functional (AFMR). 3D-TEE was performed before and immediately after clip deployment using new analysis software for MV anatomical quantification.
Results. Mean age was 78.7±7.2 years. 16 and 50 patients had respectively severe MR (4+) and moderate-severe MR (3+). Thirteen cases were unsuccessful because of unchanged or residual MR>2+. Immediately after device positioning, almost all the evaluated parameters showed a significant modification within each group with a reduction of anterior-posterior and bi-commissural MV diameters (4.0±0.6 and 3.6±0.6 cm; P<0.0001) and MV annulus area and an increase in tenting volume, tenting height and posterior mitral leaflet angle (PML α). Only anterior mitral leaflet angle (AML α) and sphericity index remained unchanged. We observed no significant difference in the sub-analysis between degenerative and all functional MR groups, although a different trend of parameters variation could be evidenced. Post-procedural tenting height was a predictor of procedural success, while at univariate analysis basal AP-D in DMR group and sphericity index, PMLα and MA height at baseline in the FMR group were significantly correlated to the entity of MR reduction at discharge.
Conclusions. Percutaneous edge-to-edge repair with MitraClip acutely changes the MV annular geometry in degenerative and both ventricular and atrial functional MR, with a different trend within each group. Tenting height variation correlates with significant MR reduction at discharge.