title: Strut chordal-sparing mitral valve replacement preserves long-term left ventricular shape and function in pigs.
abstract: OBJECTIVE
  Mitral valve replacement with preservation of the entire subvalvular apparatus entails superior postoperative left ventricular function compared with other techniques. However, this option is often not possible because of valve pathology. We hypothesized that preservation of only 4 mitral valve secondary ("strut") chordae would be functionally and geometrically equivalent to total valve preservation in the long-term setting. In a porcine mitral valve replacement model we investigated the long-term effects of 3 surgical techniques on left ventricular function and geometry: (1) total preservation of the native valve, (2) strut chordal preservation, and (3) total excision of the subvalvular apparatus.
  
  
  METHODS
  Forty 60-kg pigs were randomized to 1 of the 3 techniques. Global and regional left ventricular function and dimensions were assessed with cardiovascular magnetic resonance and conductance catheter 90 days after mitral valve replacement. Groups were compared by multivariate analysis of variance.
  
  
  RESULTS
  There was no overall difference between groups 1 and 2. Group 3 animals had (1) greater base-apex diastolic and systolic lengths, and smaller short-axis diameters, and (2) lower sphericity indices, and greater base-apex and short-axis fractional shortening than groups 1 and 2. Regional analysis showed slimming and elongation to occur primarily in the basal left ventricular segments. Left ventricular contractility and hemodynamic parameters did not differ between groups.
  
  
  CONCLUSIONS
  Strut chordal preservation was equivalent to total valve preservation during mitral valve replacement, whereas total chordal resection caused significant left ventricular slimming with compensatory increases in fractional shortening. Therefore, to preserve left ventricular geometry, special attention must be paid to maintain the valvular-ventricular continuity through the strut chordae during mitral valve replacement. This concept may have important therapeutic implications for chordal-sparing mitral valve replacement.
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby Sygehus, Brendstrupgaardsvej, Denmark. morten.smerup@ki.au.dk
authors.forename: Morten
authors.initials: M
authors.lastname: Smerup
authors.forename: Jonas
authors.initials: J
authors.lastname: Funder
authors.forename: Camilla
authors.initials: C
authors.lastname: Nyboe
authors.forename: Christian
authors.initials: C
authors.lastname: Høyer
authors.forename: Troels F
authors.initials: TF
authors.lastname: Pedersen
authors.forename: Lars
authors.initials: L
authors.lastname: Ribe
authors.forename: Steffen
authors.initials: S
authors.lastname: Ringgaard
authors.forename: Won Yong
authors.initials: WY
authors.lastname: Kim
authors.forename: Erik M
authors.initials: EM
authors.lastname: Pedersen
authors.forename: Niels T
authors.initials: NT
authors.lastname: Andersen
authors.forename: Sten L
authors.initials: SL
authors.lastname: Nielsen
authors.forename: J Michael
authors.initials: JM
authors.lastname: Hasenkam
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures / Q000379:methods; D005260:Female; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000033:anatomy & histology*; D008943:Mitral Valve / Q000601:surgery*; D013552:Swine; D013997:Time Factors; D016277:Ventricular Function, Left