Abstract 10987: Mitral Valve Annular, Leaflet and Papillary Muscle Geometry and Function in Functional Ischemic Mitral Regurgitation: New Insights from Cardiovascular Magnetic Resonance
BACKGROUND: The effects of geometric changes and functional impairment of the mitral valve (MV) annulus, leaflets, papillary muscles (PM), and left ventricle (LV), on the pathogenesis of functional ischemic mitral regurgitation (FIMR) is incompletely understood.
HYPOTHESIS: Geometric changes and functional impairment of the MV apparatus, and LV at the region of attachment of PM, cause FIMR.
METHODS: A new technique to image the MV apparatus using cardiovascular magnetic resonance (CMR) was used. A stack of cine images was acquired across the mitral valve, and at its commissures and both papillary muscles, enabling determination of the geometry, motion and function of the MV apparatus and LV. 20 patients with moderate FIMR and 10 normal controls were studied.
RESULTS: Compared to normal controls, FIMR patients had significantly impaired MV annular function with decreased pre-systolic annular contraction, annular dilatation, decreased systolic annular excursion, reduced maximal leaflet separation, increased leaflet tethering, and significant displacement of the PM posteriorly and laterally but not apically (Table 1). PM function was significantly impaired in FIMR with reduced systolic contraction. PM infarction with late gadolinium enhancement (LGE) was present in 7 posteromedial PM (35%) and 2 anterolateral PM (10%). LV LGE was present in 15 FIMR patients (75%); most frequently in LV segments 4, 5, 10 and 11 i.e. the basal and mid posterior and postero-lateral LV, to which the PM attach.
CONCLUSION: FIMR arises from myocardial infarction and LV impairment at the region of PM attachment, functional impairment and dilatation of the MV annulus, leaflet restriction, and PM dysfunction and displacement both posteriorly and laterally. PM infarction occurs in a minority of cases. These new insights provided by CMR may help in developing surgical techniques to treat FIMR more effectively.
- Cardiac surgery
- Mitral regurgitation
- Magnetic resonance imaging
- Mitral valve disease
- Ischemic heart disease
- © 2011 by American Heart Association, Inc.