Mechanics of the mitral annulus in chronic ischemic cardiomyopathy

Manuel K. Rausch, Frederick (Fred) Tibayan, Neil B. Ingels, D. Craig Miller, Ellen Kuhl

    Research output: Contribution to journalArticle

    17 Citations (Scopus)

    Abstract

    Approximately one third of all patients undergoing open-heart surgery for repair of ischemic mitral regurgitation present with residual and recurrent mitral valve leakage upon follow up. A fundamental quantitative understanding of mitral valve remodeling following myocardial infarction may hold the key to improved medical devices and better treatment outcomes. Here we quantify mitral annular strains and curvature in nine sheep 5 ± 1 weeks after controlled inferior myocardial infarction of the left ventricle. We complement our marker-based mechanical analysis of the remodeling mitral valve by common clinical measures of annular geometry before and after the infarct. After 5 ± 1 weeks, the mitral annulus dilated in septal-lateral direction by 15.2% (p = 0.003) and in commissure-commissure direction by 14.2% (p <0.001). The septal annulus dilated by 10.4% (p = 0.013) and the lateral annulus dilated by 18.4% (p <0.001). Remarkably, in animals with large degree of mitral regurgitation and annular remodeling, the annulus dilated asymmetrically with larger distortions toward the lateral-posterior segment. Strain analysis revealed average tensile strains of 25% over most of the annulus with exception for the lateral-posterior segment, where tensile strains were 50% and higher. Annular dilation and peak strains were closely correlated to the degree of mitral regurgitation. A complementary relative curvature analysis revealed a homogenous curvature decrease associated with significant annular circularization. All curvature profiles displayed distinct points of peak curvature disturbing the overall homogenous pattern. These hinge points may be the mechanistic origin for the asymmetric annular deformation following inferior myocardial infarction. In the future, this new insight into the mechanism of asymmetric annular dilation may support improved device designs and possibly aid surgeons in reconstructing healthy annular geometry during mitral valve repair.

    Original languageEnglish (US)
    Pages (from-to)2171-2180
    Number of pages10
    JournalAnnals of Biomedical Engineering
    Volume41
    Issue number10
    DOIs
    StatePublished - Oct 2013

    Fingerprint

    Mechanics
    Cardiomyopathies
    Mitral Valve
    Mitral Valve Insufficiency
    Tensile strain
    Inferior Wall Myocardial Infarction
    Repair
    Dilatation
    Geometry
    Hinges
    Equipment Design
    Surgery
    Animals
    Thoracic Surgery
    Heart Ventricles
    Sheep
    Myocardial Infarction
    Equipment and Supplies
    Direction compound

    Keywords

    • Curvature
    • Ischemic mitral regurgitation
    • Mitral annulus
    • Myocardial infarction
    • Remodeling
    • Strain

    ASJC Scopus subject areas

    • Biomedical Engineering
    • Medicine(all)

    Cite this

    Mechanics of the mitral annulus in chronic ischemic cardiomyopathy. / Rausch, Manuel K.; Tibayan, Frederick (Fred); Ingels, Neil B.; Miller, D. Craig; Kuhl, Ellen.

    In: Annals of Biomedical Engineering, Vol. 41, No. 10, 10.2013, p. 2171-2180.

    Research output: Contribution to journalArticle

    Rausch, Manuel K. ; Tibayan, Frederick (Fred) ; Ingels, Neil B. ; Miller, D. Craig ; Kuhl, Ellen. / Mechanics of the mitral annulus in chronic ischemic cardiomyopathy. In: Annals of Biomedical Engineering. 2013 ; Vol. 41, No. 10. pp. 2171-2180.
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