Ischemic mitral regurgitation is a common clinical problem with important implications on morbidity and mortality. Currently, lack of understanding of the mechanistic basis of IMR hinders the development of a reliable surgical treatment. Mitral valve repair is effective, but the results are unpredictable, and prosthetic rings alter annular and leaflet dynamics. Leaflet extension has been used clinically with anecdotal success in reducing mitral regurgitation and leaflet dynamics. Leaflet extension has been used clinically with anecdotal success in reducing mitral regurgitation in patients with ischemic heart disease. It offers the theoretical advantages of augmenting leaflet co-adaptation without disrupting annular and subvalvular dynamics. The procedure has not been rigorously tested, however, to evaluate its mechanisms or efficacy. This grant proposes to investigate the effectiveness of mitral leaflet extension in presenting mitral regurgitation in an ovine model of acute ventricular ischemia. It will test the hypothesis that extension of the anterior leaflet of the mitral valve with a pericardial patch will increase the leaflet to annular area ratio and thereby ameliorate acute ischemic mitral regurgitation. Annular ans subvalvular dynamics will be compared to that in control animals. Markers will be implanted on the left ventricle, papillary dynamics will e compared to that in control animals. Markers will be implanted on the left ventricle, papillary muscles, mitral annulus, and mitral leaflets. Anterior mitral leaflet extension will e performed on the experimental group using autologous pericardium. Temporary balloon occlusion on the circumflex coronary artery induce ischemia and IMR. Three-dimensional marker tracking, transesophageal echo, and hemodynamic data will be recorded to measure annular and subvalvular dynamics and valve competence.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32HL067563-01
Application #
6340148
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Commarato, Michael
Project Start
2001-04-09
Project End
Budget Start
2001-04-09
Budget End
2002-04-08
Support Year
1
Fiscal Year
2001
Total Cost
$40,196
Indirect Cost
Name
Stanford University
Department
Surgery
Type
Schools of Medicine
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305
Tibayan, Frederick A; Wilson, Ariane; Lai, David T M et al. (2007) Tenting volume: three-dimensional assessment of geometric perturbations in functional mitral regurgitation and implications for surgical repair. J Heart Valve Dis 16:1-7
Rodriguez, Filiberto; Langer, Frank; Harrington, Katherine B et al. (2005) Effect of cutting second-order chordae on in-vivo anterior mitral leaflet compound curvature. J Heart Valve Dis 14:592-601; discussion 601-2
Langer, Frank; Tibayan, Frederick A; Rodriguez, Filiberto et al. (2005) Altered mitral valve kinematics with atrioventricular and ventricular pacing. J Heart Valve Dis 14:286-94; discussion 294
Tibayan, Frederick A; Rodriguez, Filiberto; Langer, Frank et al. (2005) Annular or subvalvular approach to chronic ischemic mitral regurgitation? J Thorac Cardiovasc Surg 129:1266-75
Rodriguez, Filiberto; Langer, Frank; Harrington, Katherine B et al. (2004) Cutting second-order chords does not prevent acute ischemic mitral regurgitation. Circulation 110:II91-7
Timek, Tomasz A; Nielsen, Sten L; Lai, David T et al. (2004) Mitral annular size predicts Alfieri stitch tension in mitral edge-to-edge repair. J Heart Valve Dis 13:165-73
Tibayan, Frederick A; Rodriguez, Filiberto; Langer, Frank et al. (2004) Increases in mitral leaflet radii of curvature with chronic ischemic mitral regurgitation. J Heart Valve Dis 13:772-8
Rodriguez, Filiberto; Tibayan, Frederick A; Glasson, Julie R et al. (2004) Fixed-apex mitral annular descent correlates better with left ventricular systolic function than does free-apex left ventricular long-axis shortening. J Am Soc Echocardiogr 17:101-7
Rodriguez, Filiberto; Langer, Frank; Harrington, Katherine B et al. (2004) Importance of mitral valve second-order chordae for left ventricular geometry, wall thickening mechanics, and global systolic function. Circulation 110:II115-22
Tibayan, Frederick A; Rodriguez, Filiberto; Langer, Frank et al. (2004) Undersized mitral annuloplasty alters left ventricular shape during acute ischemic mitral regurgitation. Circulation 110:II98-102

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