Characterization of 3-dimensional papillary muscle displacement in in vivo ovine models of ischemic/functional mitral regurgitation

Wolfgang Bothe, Tomasz A. Timek, Frederick A. Tibayan, Mario Walther, George T. Daughters, Neil B. Ingels, D. Craig Miller

    Research output: Contribution to journalArticle

    3 Scopus citations

    Abstract

    Objective: Papillary muscle (PM) displacement contributes to ischemic/functional mitral regurgitation (IMR/FMR). The displaced PMs pull the mitral leaflets into the left ventricle (ie, toward the apex) thus hampering leaflet coaptation. Intuitively apical leaflet tethering results from apical PM displacement. The 3-dimensional directions of PM displacement are, however, incompletely characterized. Methods: Data from in vivo ovine models of IMR (6-8 weeks of posterolateral infarction, n = 12) and FMR (9-21 days of rapid left ventricular pacing, n = 11) were analyzed. All sheep had radiopaque markers implanted on the anterior and posterior PM (PPM) tips, around the mitral annulus, and on the left ventricular apex. To explore 3-dimensional PM displacement directions, differences in marker coordinates were calculated at end-systole before and during IMR/FMR using a right-handed coordinate system centered on the mitral annular “saddle horn” with the y-axis passing through the apical marker. Results: No apical PM displacement was observed during either IMR or FMR. The anterior PM displaced laterally during FMR. Posterolateral PPM displacement was observed during IMR and FMR. Conclusions: Experimental in vivo ovine models suggest posterolateral PPM displacement as a predominant pathomechanism leading to apical leaflet tethering during IMR/FMR.

    Original languageEnglish (US)
    Pages (from-to)1444-1449
    Number of pages6
    JournalJournal of Thoracic and Cardiovascular Surgery
    Volume157
    Issue number4
    DOIs
    StatePublished - Apr 2019

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    Keywords

    • cardiac intervention
    • cardiomyopathy
    • heart failure
    • mitral regurgitation
    • mitral valve
    • mitral valve repair
    • pathophysiology
    • surgery techniques

    ASJC Scopus subject areas

    • Surgery
    • Pulmonary and Respiratory Medicine
    • Cardiology and Cardiovascular Medicine

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