Multimodal image analysis and subvalvular dynamics in ischemic mitral regurgitationCentral MessagePerspective
Ahmed H. Aly, PhD,
Yoshiaki Saito, MD, PhD,
Wobbe Bouma, MD, PhD,
James J. Pilla, PhD,
Alison M. Pouch, PhD,
Paul A. Yushkevich, PhD,
Matthew J. Gillespie, MD,
Joseph H. Gorman, III, MD,
Robert C. Gorman, MD
Affiliations
Ahmed H. Aly, PhD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pa
Yoshiaki Saito, MD, PhD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Thoracic and Cardiovascular Surgery, Hirosaki University, Aomori, Japan
Wobbe Bouma, MD, PhD
Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
James J. Pilla, PhD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
Alison M. Pouch, PhD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
Paul A. Yushkevich, PhD
Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
Matthew J. Gillespie, MD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Cardiology, The Children's Hospital of Philadelphia, Philadelphia, Pa
Joseph H. Gorman, III, MD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
Robert C. Gorman, MD
Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Address for reprints: Robert C. Gorman, MD, Gorman Cardiovascular Research Group, Smilow Center for Translational Research, 3400 Civic Center Blvd, Bldg 421, 11th Floor, Room 114, Philadelphia, PA, 19104-5156.
Background: The exact geometric pathogenesis of leaflet tethering in ischemic mitral regurgitation (IMR) and the relative contribution of each component of the mitral valve complex (MVC) remain largely unknown. In this study, we sought to further elucidate mitral valve (MV) leaflet remodeling and papillary muscle dynamics in an ovine model of IMR with magnetic resonance imaging (MRI) and 3-dimensional echocardiography (3DE). Methods: Multimodal imaging combining 3DE and MRI was used to analyze the MVC at baseline, 30 minutes post–myocardial infarction (MI), and 12 weeks post-MI in ovine IMR models. Advanced 3D imaging software was used to trace the MVC from each modality, and the tracings were verified against resected specimens. Results: 3DE MV remodeling was regionally heterogenous and observed primarily in the anterior leaflet, with significant increases in surface area, especially in A2 and A3. The posterior leaflet was significantly shortened in P2 and P3. Mean posteromedial papillary muscle (PMPM) volume was decreased from 1.9 ± 0.2 cm3 at baseline to 0.9 ± 0.3 cm3 at 12 weeks post-MI (P < .05). At 12 weeks post-MI, the PMPM was predominately displaced horizontally and outward along the intercommissural axis with minor apical displacement. The subvalvular contribution to tethering is a combination of unilateral movement, outward displacement, and degeneration of the PMPM. These findings have led to a proposed new framework for characterizing PMPM dynamics in IMR. Conclusions: This study provides new insights into the complex interrelated and regionally heterogenous valvular and subvalvular mechanisms involved in the geometric pathogenesis of IMR tethering.
