Cardiac Damage in Degenerative Mitral Regurgitation Treated With Transcatheter Mitral Edge-to-Edge Repair.

Background: The extent of cardiac damage and its association with clinical outcomes in patients undergoing transcatheter edge-to-edge repair (TEER) for degenerative mitral regurgitation remains unclear. This study was aimed to investigate cardiac damage in patients with degenerative mitral regurgitation treated with TEER and its association with outcomes.

Methods: We analyzed patients with degenerative mitral regurgitation treated with TEER in the Optimized Catheter Valvular Intervention-Mitral registry, which is a prospective, multicenter observational data collection in Japan. The study subjects were classified according to the extent of cardiac damage at baseline: no extravalvular cardiac damage (stage 0), mild left ventricular or left atrial damage (stage 1), moderate left ventricular or left atrial damage (stage 2), or right heart damage (stage 3). Two-year mortality after TEER was compared using Kaplan-Meier analysis.

Results: Out of 579 study participants, 8 (1.4%) were classified as stage 0, 76 (13.1%) as stage 1, 319 (55.1%) as stage 2, and 176 (30.4%) as stage 3. Two-year survival was 100% in stage 0, 89.5% in stage 1, 78.9% in stage 2, and 75.3% in stage 3 (=0.013). Compared with stage 0 to 1, stage 2 (hazard ratio, 3.34 [95% CI, 1.03-10.81]; =0.044) and stage 3 (hazard ratio, 4.51 [95% CI, 1.37-14.85]; =0.013) were associated with increased risk of 2-year mortality after TEER. Significant reductions in heart failure rehospitalization rate and New York Heart Association functional scale were observed following TEER (both, <0.001), irrespective of the stage of cardiac damage.

Conclusions: Advanced cardiac damage is associated with an increased risk of mortality in patients undergoing TEER for degenerative mitral regurgitation.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: UMIN000023653.