Relative Impact of Surgical Mitral Repair and MitraClip on Annular Remodeling—A Potential Mechanism for Therapeutic Response to Mitral Repair for Degenerative Mitral Regurgitation

Objectives: Three-dimensional transesophageal echocardiography (TEE) is widely used to guide decision-making for mitral repair. The relative impact of surgical mitral valve repair (MVr) and MitraClip on annular remodeling is unknown. The aim was to determine the impact of both mitral repair strategies on annular geometry, including the primary outcome of annular circumference and area.Design: This was a retrospective observational study of patients who underwent mitral intervention between 2016 and 2020.Setting: Weill Cornell Medicine, a single, large, academic medical center.Participants: The population comprised 50 patients with degenerative mitral regurgitation (MR) undergoing MVr.Interventions: Elective MVr and TEE.Measurements and Main Results: Patients undergoing MitraClip or surgical MVr were matched (1:1) for sex and coronary artery disease. Mitral annular geometry indices were quantified on intraprocedural three-dimensional TEE. Mild or less MR on follow-up transthoracic echocardiography defined optimal response. Patients undergoing MitraClip were older (80 ± eight v 66 ± six years; p < 0.001) but were otherwise similar to surgical patients. Patients undergoing MitraClip had larger baseline left atrial and ventricular sizes, increased tenting height, and volume (p < 0.01), with a trend toward increased annular area (p = 0.23). MitraClip and surgery both induced immediate mitral annular remodeling, including decreased area, circumference, and tenting height (p < 0.001), with greater remodeling with surgical repair. At follow-up (4.1 ± 9.0 months) optimal response (≤ mild MR) was ∼twofold more common with surgery than MitraClip (81% v 46%; p = 0.02). The relative reduction in annular circumference (odds ratio [OR] 1.05 [1.00-1.09] per cm; p = 0.04) and area (OR 1.03 [1.00-1.05] per cm2; p = 0.049) were both associated with optimal response.Conclusions: Surgical MVr and MitraClip both reduce annular size, but repair-induced remodeling is greater with surgery and associated with an increased likelihood of optimal response.