Effects of hemodynamic alterations on anterior mitral leaflet curvature during systole.
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.
Sakamoto
Hiroaki
H
Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pa 19104, USA.
Parish
Landi M
LM
Hamamoto
Hirotsugu
H
Enomoto
Yoshiharu
Y
Zeeshan
Ahmad
A
Plappert
Theodore
T
Jackson
Benjamin M
BM
St John-Sutton
Martin G
MG
Gorman
Robert C
RC
Gorman
Joseph H
JH
D000818:Animals; D008943:Mitral Valve / Q000033:anatomy & histology* / Q000502:physiology*; D012756:Sheep; D013599:Systole