title: Neochord placement versus triangular resection in mitral valve repair: A finite element model.
abstract: 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 (NCs) results in lower stress than leaflet resection (LR).
  
  
  
  Magnetic resonance imaging 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.
  
  
  
  (1) NC placement resulted in stable posterior leaflet stress: Baseline versus 2 NC at end diastole (ED), 12.1 versus 12.0 kPa, at end systole (ES) 20.3 versus 21.7 kPa. (2) In contrast, LR increased posterior leaflet stress: Baseline versus LR at ED 12.1 versus 40.8 kPa, at ES 20.3 versus 46.1 kPa. (3) All repair types reduced anterior leaflet stress: Baseline versus 2 NC versus LR 34.2 versus 25.8 versus 20.6 kPa at ED and 80.8 versus 76.8 versus 67.8 kPa at ES. (4) The addition of RA reduced leaflet stress relative to repair without RA.
  
  
  
  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.
authors.affiliation: East Bay Surgical Residency, University of California, San Francisco, California.
authors.forename: Ashley E
authors.initials: AE
authors.lastname: Morgan
authors.affiliation: College of Medicine, University of California, San Francisco, California.
authors.forename: Joe L
authors.initials: JL
authors.lastname: Pantoja
authors.affiliation: Department of Cardiothoracic Surgery, New York University, New York, New York; Department of Cardiothoracic Surgery, New York Harbor Veterans Affairs Medical Center, New York, New York.
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Grossi
authors.affiliation: Department of Surgery, University of California, San Francisco, California; Department of Bioengineering, University of California, San Francisco, California; Department of Surgery, Veterans Affairs Medical Center, San Francisco, California.
authors.forename: Liang
authors.initials: L
authors.lastname: Ge
authors.affiliation: Department of Medicine (Cardiology), Weill Cornell Medical College, New York, New York; Department of Radiology, Weill Cornell Medical College, New York, New York.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Weinsaft
authors.affiliation: Department of Surgery, University of California, San Francisco, California; Department of Bioengineering, University of California, San Francisco, California; Department of Surgery, Veterans Affairs Medical Center, San Francisco, California. Electronic address: mark.ratcliffe@med.va.gov.
authors.forename: Mark B
authors.initials: MB
authors.lastname: Ratcliffe
mesh_terms: D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D058386:Mitral Valve Annuloplasty / Q000295:instrumentation / Q000379:methods*; D008944:Mitral Valve Insufficiency / Q000601:surgery*; D008953:Models, Anatomic; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013312:Stress, Physiological
keywords: Cardiac mechanics; Finite element modeling; Mitral valve repair; Surgical simulation