Attenuated Mitral Leaflet Enlargement Contributes to Functional Mitral Regurgitation After Myocardial Infarction |
| |
Institution: | 1. Institut Universitaire de Cardiologie et de Pneumologie de Québec–Université Laval, Québec City, Quebec, Canada;2. Center for Excellence in Vascular Biology, Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts;3. Division of Cardiology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea;4. Cardiac Ultrasound Lab, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts;5. Vascular Biology Program and Department of Surgery, Boston Children’s Hospital and Department of Surgery, Harvard Medical School, Boston, Massachusetts |
| |
Abstract: | BackgroundMitral leaflet enlargement has been identified as an adaptive mechanism to prevent mitral regurgitation in dilated left ventricles (LVs) caused by chronic aortic regurgitation (AR). This enlargement is deficient in patients with functional mitral regurgitation, which remains frequent in the population with ischemic cardiomyopathy. Maladaptive fibrotic changes have been identified in post-myocardial infarction (MI) mitral valves. It is unknown if these changes can interfere with valve growth and whether they are present in other valves.ObjectivesThis study sought to test the hypothesis that MI impairs leaflet growth, seen in AR, and induces fibrotic changes in mitral and tricuspid valves.MethodsSheep models of AR, AR + MI, and controls were followed for 90 days. Cardiac magnetic resonance, echocardiography, and computed tomography were performed at baseline and 90 days to assess LV volume, LV function, mitral regurgitation and mitral leaflet size. Histopathology and molecular analyses were performed in excised valves.ResultsBoth experimental groups developed similar LV dilatation and dysfunction. At 90 days, mitral valve leaflet size was smaller in the AR + MI group (12.8 ± 1.3 cm2 vs. 15.1 ± 1.6 cm2, p = 0.03). Mitral regurgitant fraction was 4% ± 7% in the AR group versus 19% ± 10% in the AR + MI group (p = 0.02). AR + MI leaflets were thicker compared with AR and control valves. Increased expression of extracellular matrix remodeling genes was found in both the mitral and tricuspid leaflets in the AR + MI group.ConclusionsIn these animal models of AR, the presence of MI was associated with impaired adaptive valve growth and more functional mitral regurgitation, despite similar LV size and function. More pronounced extracellular remodeling was observed in mitral and tricuspid leaflets, suggesting systemic valvular remodeling after MI. |
| |
Keywords: | aortic regurgitation LV remodeling mitral regurgitation mitral valve myocardial infarction 3D"} {"#name":"keyword" "$":{"id":"kwrd0040"} "$$":[{"#name":"text" "_":"3 dimensional AR"} {"#name":"keyword" "$":{"id":"kwrd0050"} "$$":[{"#name":"text" "_":"aortic regurgitation CT"} {"#name":"keyword" "$":{"id":"kwrd0060"} "$$":[{"#name":"text" "_":"computed tomography FMR"} {"#name":"keyword" "$":{"id":"kwrd0070"} "$$":[{"#name":"text" "_":"functional mitral regurgitation LV"} {"#name":"keyword" "$":{"id":"kwrd0080"} "$$":[{"#name":"text" "_":"left ventricle MI"} {"#name":"keyword" "$":{"id":"kwrd0090"} "$$":[{"#name":"text" "_":"myocardial infarction MMP"} {"#name":"keyword" "$":{"id":"kwrd0100"} "$$":[{"#name":"text" "_":"matrix metalloproteinase MRI"} {"#name":"keyword" "$":{"id":"kwrd0110"} "$$":[{"#name":"text" "_":"magnetic resonance imaging MV"} {"#name":"keyword" "$":{"id":"kwrd0120"} "$$":[{"#name":"text" "_":"mitral valve PCR"} {"#name":"keyword" "$":{"id":"kwrd0130"} "$$":[{"#name":"text" "_":"polymerase chain reaction TGF"} {"#name":"keyword" "$":{"id":"kwrd0140"} "$$":[{"#name":"text" "_":"transforming growth factor TV"} {"#name":"keyword" "$":{"id":"kwrd0150"} "$$":[{"#name":"text" "_":"tricuspid valve |
本文献已被 ScienceDirect 等数据库收录! |
|