title: Transapical neochord implantation: is tension of artificial chordae tendineae dependent on the insertion site?
abstract: OBJECTIVE
  Transapical chordae tendineae replacement is a promising new approach for mitral leaflet prolapse. However, animal studies have raised concerns that the tension of the transapically fixated artificial neochordae might be greater than the tension in the neochordae attached to papillary muscle tips, thereby reducing repair durability.
  
  
  METHODS
  In eight 80-kg pigs, the primary anterior leaflet chordae were replaced by a 5-0 polytetrafluoroethylene neochord using a miniature in-line force transducer. The neochord was attached first to the anterior papillary muscle and, on a second cardiac bypass, transapically to the left ventricle apex. Occlusion of the inferior vena cava was performed to examine the effect of left ventricle pressure changes on neochord tension to adjust the crude data to 95 mm Hg. The maximum slope of the chordal tension curve was calculated to compare curve patterns. The data are presented as the mean ± standard deviation.
  
  
  RESULTS
  The following tension was measured in the neochordae during papillary muscle and transapical fixation, respectively: peak tension (crude, 0.39 ± 0.32 vs 0.50 ± 0.25 N, P = .17; adjusted, 0.41 ± 0.30 vs 0.46 ± 0.27 N, P = .22), mid-systolic tension (crude, 0.19 ± 0.12 vs 0.19 ± 0.15 N, P = .96; adjusted, 0.28 ± 0.16 vs 0.19 ± 0.11 N, P = .12). There was a significantly lower maximum slope (dF/dtmax) of the neochord tension curves after papillary muscle fixation compared with transapical fixation (7.4 ± 6.9 vs 10.3 ± 7.7 N/s, P = .028).
  
  
  CONCLUSIONS
  Overall, the chordal insertion site had little influence on the tension in the artificial neochordae compared with the interindividual variation. However, abnormal tension fluctuations in the transapically fixated neochordae might predispose to leaflet tears and early repair failure.
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby, Denmark; Institute of Clinical Medicine, University of Aarhus, Aarhus, Denmark. Electronic address: hjensen@dadlnet.dk.
authors.forename: Henrik
authors.initials: H
authors.lastname: Jensen
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby, Denmark; Department of Biomedical Engineering, Aarhus University Engineering College, Aarhus, Denmark.
authors.forename: Morten O
authors.initials: MO
authors.lastname: Jensen
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Farhad
authors.initials: F
authors.lastname: Waziri
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby, Denmark; Institute of Clinical Medicine, University of Aarhus, Aarhus, Denmark.
authors.forename: Jesper L
authors.initials: JL
authors.lastname: Honge
authors.affiliation: Department of Anesthesiology, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Erik
authors.initials: E
authors.lastname: Sloth
authors.affiliation: Research Unit for General Practice, Aarhus University Faculty of Health Sciences, Aarhus, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Fenger-Gron
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Sten L
authors.initials: SL
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D002815:Chordae Tendineae / Q000503:physiopathology / Q000601:surgery*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation*; D006439:Hemodynamics; D008943:Mitral Valve / Q000503:physiopathology / Q000601:surgery*; D023421:Models, Animal; D010210:Papillary Muscles / Q000503:physiopathology / Q000601:surgery; D011138:Polytetrafluoroethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D013552:Swine
chemical_list: D011138:Polytetrafluoroethylene