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 journalArticlepeer-review

13 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
Externally publishedYes

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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