Attenuated Mitral Leaflet Enlargement Contributes to Functional Mitral Regurgitation After Myocardial Infarction
| Autor: | Marie-Claude Drolet, J. Luis Guerrero, Patrick Mathieu, Marie-Annick Clavel, Jonathan Beaudoin, Claudia Côté-Laroche, Ons Marsit, Marie Arsenault, Marie-Chloé Boulanger, Dae-Hee Kim, Robert A. Levine, Philipp E. Bartko, Elena Aikawa, Joyce Bischoff, Mark D. Handschumacher, Sandra Hadjadj, Marc-André Bouchard, Jacques Couet, Marine Clisson, Philippe Pibarot |
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| Rok vydání: | 2019 |
| Předmět: |
Male
medicine.medical_specialty Population Aortic Valve Insufficiency Echocardiography Three-Dimensional Myocardial Infarction Myocardial Ischemia Infarction Regurgitation (circulation) 030204 cardiovascular system & hematology 03 medical and health sciences 0302 clinical medicine Mitral valve Internal medicine medicine Animals cardiovascular diseases 030212 general & internal medicine Myocardial infarction education Mitral regurgitation education.field_of_study Ischemic cardiomyopathy Sheep Ventricular Remodeling business.industry Mitral Valve Insufficiency medicine.disease Fibrosis Magnetic Resonance Imaging Extracellular Matrix medicine.anatomical_structure Regurgitant fraction cardiovascular system Cardiology Mitral Valve Female Tricuspid Valve Cardiology and Cardiovascular Medicine business Tomography X-Ray Computed |
| Zdroj: | Journal of the American College of Cardiology. 75(4) |
| ISSN: | 1558-3597 |
| Popis: | Background Mitral 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. Objectives This study sought to test the hypothesis that MI impairs leaflet growth, seen in AR, and induces fibrotic changes in mitral and tricuspid valves. Methods Sheep 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. Results Both 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. Conclusions In 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. |
| Databáze: | OpenAIRE |
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