title: The influence of annuloplasty ring geometry on mitral leaflet curvature.
abstract: BACKGROUND
  The effect of mitral leaflet curvature on stress reduction is an important mechanism in optimizing valve function. We hypothesize that annuloplasty ring shape could directly influence leaflet curvature and, potentially, repair durability. We describe an echocardiographically based methodology for quantifying mitral valve geometry and its application to the characterization of ovine mitral valve geometry before and after implantation of an annuloplasty ring.
  
  
  METHODS
  Multiple mitral annular and leaflet geometric variables were calculated for 8 naïve adult male sheep using real-time three-dimensional echocardiographic images. These indexes were recalculated after annuloplasty using a 30-mm Carpentier-Edward Physio ring (n = 4; Edwards Lifesciences, Irvine, CA) or a 30-mm saddle ring (n = 4).
  
  
  RESULTS
  After implantation of the Physio ring, the annular height to commissural width ratio (AHCWR) decreased from 19.4% +/- 2.3% to 11.1% +/- 2.5% (p = 0.06). After implantation of the saddle ring, AHCWR increased from 19.6% +/- 1.3% to 24.3% +/- 1.3% (p < 0.05). Statistically significant increases in three-dimensional Gaussian curvature occurred after implantation within six defined leaflet regions (A1 to A3, P1 to P3) of the saddle ring but only within the P1 and P3 leaflet regions with the Physio ring.
  
  
  CONCLUSIONS
  Annuloplasty ring shape affects leaflet curvature. Implantation of a saddle ring reflecting normal human annular geometry augmented ovine annular nonplanarity and increased three-dimensional leaflet curvature across the entire mitral valve surface. The Physio ring decreased annular nonplanarity and increased leaflet curvature only across limited regions of the posterior leaflet. These findings confirm the hypothesis that ring design influences leaflet curvature.
authors: The Harrison Department of Surgical Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-4283, USA.
authors: Liam P
authors: LP
authors: Ryan
authors: Benjamin M
authors: BM
authors: Jackson
authors: Hirotsuga
authors: H
authors: Hamamoto
authors: Thomas J
authors: TJ
authors: Eperjesi
authors: Theodore J
authors: TJ
authors: Plappert
authors: Martin
authors: M
authors: St John-Sutton
authors: Robert C
authors: RC
authors: Gorman
authors: Joseph H
authors: JH
authors: Gorman
mesh_terms: D000818:Animals; D004452:Echocardiography; D006350:Heart Valve Prosthesis; D008297:Male; D008943:Mitral Valve / Q000033:anatomy & histology*; D011474:Prosthesis Design; D012756:Sheep