title: Effects of hemodynamic alterations on anterior mitral leaflet curvature during systole.
abstract: OBJECTIVE
  The application of repair techniques to treat mitral valve incompetence has increased progressively during the past 20 years. Unfortunately, recent reports have demonstrated the longevity of these repairs to be less than previously believed. Most repair failures are stress related. Computational models to optimize valve repair are in development, but to be brought to fruition, a better understanding of dynamic leaflet geometry is necessary. In this study, sonomicrometry was used in an ovine model to compute systolic leaflet curvature at varying afterloads and states of contractility.
  
  
  METHODS
  The anterior leaflet of 12 sheep was instrumented with 5 piezoelectric transducers in a cruciate array. Systolic blood pressure ranged from 90 to 200 mm Hg with increasing phenylephrine hydrochloride infusion. Epinephrine was used to vary contractile state. Leaflet curvature was calculated continuously (200 Hz) during systole.
  
  
  RESULTS
  Anterior leaflet curvature in the septolateral direction was double that in the intercommisural direction. There were also significant changes in leaflet curvature during systole. Curvature in neither direction was affected by afterload. Epinephrine augmented intercommisural curvature in a dose-independent fashion, whereas it had no effect on curvature in the septolateral direction.
  
  
  CONCLUSIONS
  Dynamic mitral anterior leaflet geometry was found to be amazingly constant over a wide range of hemodynamic conditions. These data provide information about leaflet geometry that will aid in the construction of realistic computational models. Such models may facilitate the design of annuloplasty rings and surgical techniques that minimize leaflet stress and increase mitral valve repair longevity.
authors.affiliation: Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pa 19104, USA.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Landi M
authors.initials: LM
authors.lastname: Parish
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Hamamoto
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Enomoto
authors.forename: Ahmad
authors.initials: A
authors.lastname: Zeeshan
authors.forename: Theodore
authors.initials: T
authors.lastname: Plappert
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Jackson
authors.forename: Martin G
authors.initials: MG
authors.lastname: St John-Sutton
authors.forename: Robert C
authors.initials: RC
authors.lastname: Gorman
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Gorman
mesh_terms: D000818:Animals; D008943:Mitral Valve / Q000033:anatomy & histology* / Q000502:physiology*; D012756:Sheep; D013599:Systole