Prognostic value of leaflet coaptation gap in transcatheter edge-to-edge repair for functional mitral regurgitation.

Background: Coaptation gap (CG) is one of the challenging anatomies of mitral transcatheter edge-to-edge repair (TEER), but its impact on patient outcomes is unclear. This study aimed to evaluate the impact of CG on procedural and clinical outcomes in patients with functional mitral regurgitation (MR).

Methods: Data from 2140 patients undergoing TEER for functional MR were analysed, focusing on the presence of CG, which is a missing leaflet coaptation between the anterior and posterior leaflets during systole. The primary outcome was a composite of death, heart failure hospitalisation and mitral valve reintervention.

Results: Of the 2140 patients, 219 (10%) had CG and 1921 (90%) did not, as assessed by baseline transoesophageal echocardiography. In patients with CG, baseline MR grade and New York Heart Association (NYHA) functional class were more severe, and long/wide clip types were used more frequently. Post-TEER, patients with CG had significantly lower achievement of MR grade ≤2+ (93%) and ≤1+ (65%) compared with patients without CG (97%, p<0.01; 82%, p<0.01, respectively). NYHA functional class at 1 year was similar in both groups. The cumulative incidence of the primary outcome was comparable between CG and non-CG groups (51% vs 53% at 3 years, p=0.71). While residual MR grade 2+ was associated with the higher primary outcome incidence compared with ≤1+ in patients without CG (p<0.01), no significant difference was found in patients with CG (p=0.51).

Conclusion: CG was associated with less MR reduction but with no clear difference in adverse clinical outcomes after TEER. Similar outcomes between residual MR grade 2+ and ≤1+ in CG patients highlight the importance of procedural endpoint in anatomically challenging cases.

Trial registration number: UMIN000023653.