Abstract 4146669: Impacts of left ventricle–mitral annulus orifice area mismatch annuloplasty for advanced severe degenerative mitral regurgitation

Background: In advanced severe degenerative mitral regurgitation (asDMR, i.e., C2 to D stage DMR), an overt deterioration of the mitral valve (MV) apparatus and left ventricular (LV) enlargement are typically observed. The negative impacts of a mismatch between the left ventricular end-systolic dimension (LVESD) and MV ring size on mitral regurgitation (MR) recurrence have been established in secondary MR, while its impacts on asDMR prognosis remains unknown. Hypothesis: LVESD/MV ring size ratio may impact on asDMR prognosis. Goals: To verify the impact and to reveal its side effects. Methods: We retrospectively analyzed patients diagnosed with asDMR who underwent mitral valve repair and annuloplasty from 2008 to 2019. Patients were followed up to April 2024. Primary outcomes included 10-year moderate or severe mitral stenosis (MS), recurrent MR, and death. Prosthetic orifice areas (POA) were obtained from official instructions. LVESD/POA was introduced as a novel parameter to identify LV-MV mismatch and non-mismatch. Results: A total of 450 eligible patients were enrolled. During the follow-up of 5.8 ± 2.3 years, 60 recurrent MRs, 71 MSs, and 46 deaths were observed. At 3rd, 5th, and 10th years after surgery, rates of freedom from recurrent MR were 98.1%, 92.4%, and 65.4%, respectively; rates of freedom from MS rates were 99.0%, 94.9%, and 59.4%, respectively; survival rates were 97.8%, 94.9%, and 69.6%, respectively. In multivariable Cox regression analysis, only a larger LVESD/POA ratio (HR: 3.50; 95% CI: 1.98-6.16; p < 0.001) was associated with recurrent MR. ROC curve determined an optimal LVESD/POA cutoff value of 11.52 mm/m 2 (AUC = 0.88, p < 0.001) for recurrent MR prediction. In subgroup analysis, mismatch group (LVESD/POA > 11.52 mm/m 2 ) had higher cumulative recurrent MR rate (log-rank p < 0.001), MS rate (log-rank p < 0.001), and survival rate (log-rank p < 0.001). In mismatch group, ring cohort exhibited higher cumulative MS rate (log-rank p = 0.027) and higher cumulative recurrent MR rate (log-rank p = 0.013). However, in the non-mismatch group, the cumulative MS and MR rates were comparable between the ring and band cohorts (log-rank p = 0.53). Conclusion: LV-MV mismatch annuloplasty increases the risks of recurrent MR, MS, and death. LVESD/POA ratio effectively predicts recurrent MR in asDMR. In patients with significant LV dilation, a posterior band may be preferable to a complete ring for downsized annuloplasty.