Comprehensive assessment of mitral valve geometry and cardiac remodeling with three-dimensional echocardiography after percutaneous mitral valve repair

MitraClip is a validated treatment for significant mitral regurgitation (MR) in high-risk patients. Aims of the study were to evaluate immediate changes in mitral valve (MV) geometry induced by MitraClip and correlations between baseline geometry and cardiac remodeling. Eighty patients who underwent MitraClip for primary (48%) or secondary (52%) MR were enrolled. Intraoperative transesophageal echocardiographic 3D images were acquired immediately before and after the procedure for MV annulus (MVA) morphology analysis. Transthoracic 3D echocardiography was performed preoperatively and at 6 months follow-up (6MFU). Patients were classified on the basis of MR reduction (ΔMR) at 6MFU as Optimal (ΔMR ≥ 2) or Suboptimal (ΔMR < 2). An optimal result was reached in 60 (75%) patients, whereas 20 subjects showed a ΔMR< 2 at 6MFU. The Optimal showed significantly smaller baseline MVA (antero-posterior diameter 4.05 ± 0.59 vs 4.43 ± 0.68 cm; anterolateral-posteromedial diameter 4.38 ± 0.56 vs 4.70 ± 0.73 cm; MVA circumference 14.1 ± 1.7 vs 15.1 ± 2.3 cm; and 3D area 14.8 ± 3.9 vs 17.4 ± 5.3 cm2), lower sphericity index and nonplanar angle compared with Suboptimal. A value of antero-posterior diameter ≥4.44cm was identified (receiver-operating characteristic curve) as a possible cut-off for preoperative identification of Suboptimal patients. Postoperatively, MitraClip induced reduction of MVA flattening (nonplanar angle), sphericity index, and size (as expressed by antero-posterior diameter, MVA circumference and area). At 6MFU, the Optimal showed significant decrease in left ventricular volumes and pulmonary artery systolic pressure. In conclusion, MitraClip induces remarkable changes in MVA geometry and favorable left ventricular remodeling is detected in patients with optimal mid-term outcome; a preprocedural antero-posterior diameter <4.44cm seems to be a potential predictor of mid-term optimal result.