Volume 14 Supplement 1
Mitral leaflet dynamics in ischemic mitral regurgitation using high resolution MRI
© Levack et al; licensee BioMed Central Ltd. 2012
Published: 1 February 2012
Leaflet malcoaptation in ischemic mitral regurgitation (IMR) is thought to be caused by a combination of annular dilatation and leaflet tethering due to subvalvular ventricular remodeling. Despite this, little is known regarding leaflet dynamics in IMR. Using high temporal resolution MRI we describe, for the first time, the influence of post infarction ventricular remodeling on leaflet motion.
A porcine model of IMR was used. Using direct coronary ligation, five animals were subjected to a posterior myocardial infarction. Eight weeks post infarction animals underwent 4D time-resolved, flow sensitive MRI imaging, 3D MRI cine imaging and 2D phase contrast, high temporal resolution imaging of the mitral valve, left ventricle and aortic outflow tract. Three naïve animals underwent identical imaging protocols to serve as controls. Net mitral and aortic transvalvular flows were determined as well as left ventricular volumes and ejection fraction. Anterior to posterior mid-leaflet tip distances were measured throughout the cardiac cycle for quantification of temporal leaflet dynamics. Statistical significance was computed by ANOVA.
Ventricular dilatation in IMR leads to significant increases in leaflet separation during diastole. The use of high temporal resolution MRI for assessing dynamic leaflet motion can serve as an important addition in future studies looking at the effects of various therapeutic options on valve physiology.
This work was supported by grants from the National Heart, Lung and Blood Institute of the National Institutes of Health, Bethesda, MD (HL63954, HL73021 and HL103723). R. Gorman and J. Gorman are supported by individual Established Investigator Awards from the American Heart Association, Dallas, TX.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.