Change in Mitral Annular Size and Geometry after MitraClip® Implantation in Patients with Functional and Degenerative Mitral Regurgitation

BACKGROUND: MitraClip® therapy is an alternative to conventional surgery. The aim was to characterize the mitral annular geometry pre- and postrepair with the MitraClip® taking into account the regurgitation mechanism. METHODS: We retrospectively collected pre- and postprocedural transesophageal echocardiography data in 46 patients. Patients were categorized as having isolated degenerative (DMR, n = 18), isolated functional (FMR, n = 9) or a combination of both functional and degenerative mitral regurgitation (MMR, n = 19). RESULTS: A significant reduction in septolateral (SL) diameters in all patients occurred. Noteworthy, in those with DMR, there was no significant change in intercommissural (IC) diameters whereas in those with FMR and MMR, it increased significantly in systole (FMR: +2.8 ± 3.4 mm, P = 0.03, MMR: +2.1 ± 2.6 mm, P = 0.002). In DMR, a significant reduction in mitral annular areas post-procedure was observed (-1.8 ± 2.3 cm(2), P = 0.001 in diast., -0.8 ± 1.0 cm(2), P = 0.004 in syst.). In patients with FMR and MMR, though the SL diameter decreased, this occurred at the expense of an increase in IC diameter causing a change in annular shape but leaving the annular area unchanged. Nevertheless, a comparable reduction in regurgitant severity (DMR: P = <0.001; FMR: P = 0.003; MMR: P = <0.001) and improvement in functional class occurred regardless of regurgitant mechanism. CONCLUSIONS: Though changes in mitral annular geometry after MitraClip® repair differ depending on regurgitant mechanism, this does not appear to have an impact on residual regurgitation or clinical status in the short-term.