Neochord Placement vs Triangular Resection in Mitral Valve Repair: A Finite Element Model

, Abstract Background— Recurrent mitral regurgitation after mitral valve repair is common, occurring in nearly 50% of patients within 10 years of surgery. Durability of repair is partly related to stress distribution over the mitral leaflets. We hypothesized that repair with neochords (NC) results in lower stress than leaflet resection (LR). Materials and Methods— MRI and 3D echocardiography were performed before surgical repair of P2 prolapse in a single patient. A finite element model of the left ventricle and mitral valve was created previously, and the modeling program LS-DYNA was used to calculate leaflet stress for the following repairs: Triangular LR; LR with ring annuloplasty (LR + RA); One NC; Two NCs; and 2NC + RA. Results— 1) NC placement resulted in stable posterior leaflet stress: Baseline vs 2 NC at end diastole (ED),12.1 vs 12.0 kPa, at end systole (ES) 20.3 vs 21.7 kPa. 2) In contrast, LR increased posterior leaflet stress: Baseline vs LR at ED 12.1 vs 40.8 kPa, at ES 20.3 vs 46.1 kPa. 3) All repair types reduced anterior leaflet stress: Baseline vs 2 NC vs LR 34.2 vs 25.8 vs 20.6 kPa at ED and 80.8 vs 76.8 vs 67.8 kPa at ES. 4) The addition of RA reduced leaflet stress relative to repair without RA. Conclusions— Neochord repair restored normal leaflet coaptation without creating excessive leaflet stress, whereas leaflet resection more than doubled stress across the posterior leaflet. The excess stress created by leaflet resection was partially, but not completely, mitigated by ring annuloplasty.