Annuloplasty Ring Size and Long-term Durability after Degenerative Mitral Valve Repair

BACKGROUND: Annuloplasty ring sizing has an important role in surgical mitral valve (MV) repair for degenerative mitral regurgitation (MR). Larger rings are generally preferred for degenerative disease as they confer optimal hemodynamics, reduce systolic anterior motion and restore annular geometry. METHODS: We analyzed a retrospective, single-surgeon cohort of 503 patients who underwent MV repair for MR from 2008-2024. The primary endpoint was MV repair failure, defined as reintervention, recurrent MR or mitral stenosis. Patients were stratified by annuloplasty ring size quartiles. Kaplan-Meier survival and multivariable Cox proportional hazards models were used, incorporating a time-dependent spline interaction to capture long-term effects. RESULTS: Over a median follow-up of 5.3 years [IQR: 2.8-8.2], larger annuloplasty ring size was significantly associated with higher rates of late repair failure. Failure rates by ring size quartile were: ≤32 mm (2.0%), 33-34 mm (3.2%), 35-36 mm (5.7%), and >36 mm (7.3%). Ring size remained an independent predictor of MV repair failure (HR 1.06 [1.01-1.10], p < 0.01), with time-dependent analysis showing increased hazard beyond 11.7 years. A threshold of >34 mm was identified as the optimal cut-point for predicting long-term failure. CONCLUSIONS: Larger annuloplasty ring size is independently associated with late mitral valve repair failure. These findings support more physiologic sizing strategies to optimize long-term durability following MV repair for degenerative MR.