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Persson RM, Aguilera HMD, Grong K, Kvitting JPE, Stangeland L, Haaverstad R, Urheim S, Prot VE. Characterisation of global and regional mitral annular strains in an acute porcine model. INTERDISCIPLINARY CARDIOVASCULAR AND THORACIC SURGERY 2024; 39:ivae154. [PMID: 39254640 PMCID: PMC11401742 DOI: 10.1093/icvts/ivae154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 08/01/2024] [Accepted: 09/06/2024] [Indexed: 09/11/2024]
Abstract
OBJECTIVES This study aimed to explore regional mitral annular strain using a novel computational method. METHODS Eight pigs underwent implantation with piezoelectric transducers around the mitral annulus. Interventions of pre- and afterload were performed by inferior vena cava constriction and endovascular balloon occlusion of the descending aorta. The mitral annulus was reconstructed in a mathematical model and divided into 6 segments. Global and segmental annular strain were calculated from a discrete mathematical representation. RESULTS Global annular strain gradually decreased after isovolumetric contraction until late systole. Mitral annular end-systolic strain demonstrated shortening in all segments except the anterior segment, which showed the least deformation. The P2 annular segment demonstrated the most end-systolic shortening (-7.6 ± 1.1% at baseline, P < 0.001 compared to anterior segment). Systolic global annular strain showed no significant change in response to load interventions but correlated positively with left ventricular contractility at baseline and after preload reduction. CONCLUSIONS Mitral annular systolic strain demonstrates cyclical variations with considerable regional heterogeneity, with the most pronounced deformation in posterior annular segments. Measurements appear independent of changes to pre- and afterload.
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Affiliation(s)
- Robert Matongo Persson
- Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Hans Martin Dahl Aguilera
- Department of Structural Engineering, Faculty of Engineering Science, The Norwegian University of Science and Technology, Trondheim, Norway
| | - Ketil Grong
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - John-Peder Escobar Kvitting
- Department of Cardiothoracic Surgery, Oslo University Hospital, Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lodve Stangeland
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Rune Haaverstad
- Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Stig Urheim
- Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Victorien Emile Prot
- Department of Structural Engineering, Faculty of Engineering Science, The Norwegian University of Science and Technology, Trondheim, Norway
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Silva-Verissimo W, El Louali F, Godio-Raboutet Y, Leblond L, Sourdon J, Rapacchi S, Evin M. Traction mechanical characterization of porcine mitral valve annulus. J Biomech 2023; 146:111396. [PMID: 36459849 DOI: 10.1016/j.jbiomech.2022.111396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 11/07/2022] [Accepted: 11/16/2022] [Indexed: 11/21/2022]
Abstract
The Mitral Annulus (MA) is an anisotropic, fibrous, flexible and dynamical structure. While MA dynamics are well documented, its passive mechanical properties remain poorly investigated to complete the design of adequate prostheses. Mechanical properties in traction on four sections of the MA (aortic, left, posterior and right segments) were assessed using a traction test system with a 30 N load cell and pulling jaws for sample fixation. Samples were submitted to a 1.5 N pre-load, 10 pre-conditioning cycles. Three strain rates were tested (5 %/min, 7 %/min and 13 %/min), the first two up to 10 % strain and the last until rupture. High-resolution diffusion-MRI provided microstructural mapping of fractional anisotropy and mean diffusion within muscle and collagen fibres. Ten MA from porcine hearts were excised resulting in 40 tested samples, out of which 28 were frozen prior to testing. Freezing samples significantly increased Young Moduli for all strain rates. No significant differences were found between Young Moduli at different strain rates (fresh samples 2.4 ± 1.1 MPa, 3.8 ± 2.2 MPa and 3.1 ± 1.8 MPa for increasing strain rates in fresh samples), while significant differences were found when comparing aortic with posterior and posterior with lateral (p < 0.012). Aortic segments deformed the most (24.1 ± 9.4 %) while lateral segments endured the highest stress (>0.3 MPa), corresponding to higher collagen fraction (0.46) and fractional anisotropy. Passive machinal properties differed between aortic and lateral segments of the MA. The process of freezing samples altered their mechanical properties. Underlying microstructural differences could be linked to changes in strain response.
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Affiliation(s)
| | - F El Louali
- Aix Marseille Univ, Univ Gustave Eiffel, LBA, Marseille, France; AP-HM, Marseille, France
| | | | | | - Joevin Sourdon
- Aix-Marseille University, CNRS, CRMBM, Marseille, France
| | - S Rapacchi
- Aix-Marseille University, CNRS, CRMBM, Marseille, France
| | - Morgane Evin
- Aix Marseille Univ, Univ Gustave Eiffel, LBA, Marseille, France.
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Frishman S, Kight A, Pirozzi I, Maddineni S, Imbrie-Moore AM, Karachiwalla Z, Paulsen MJ, Kaiser AD, Woo YJ, Cutkosky MR. DynaRing: A Patient-Specific Mitral Annuloplasty Ring With Selective Stiffness Segments. J Med Device 2022; 16:031009. [PMID: 35646225 PMCID: PMC9125864 DOI: 10.1115/1.4054445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/23/2022] [Indexed: 09/03/2023] Open
Abstract
Annuloplasty ring choice and design are critical to the long-term efficacy of mitral valve (MV) repair. DynaRing is a selectively compliant annuloplasty ring composed of varying stiffness elastomer segments, a shape-set nitinol core, and a cross diameter filament. The ring provides sufficient stiffness to stabilize a diseased annulus while allowing physiological annular dynamics. Moreover, adjusting elastomer properties provides a mechanism for effectively tuning key MV metrics to specific patients. We evaluate the ring embedded in porcine valves with an ex-vivo left heart simulator and perform a 150 million cycle fatigue test via a custom oscillatory system. We present a patient-specific design approach for determining ring parameters using a finite element model optimization and patient MRI data. Ex-vivo experiment results demonstrate that motion of DynaRing closely matches literature values for healthy annuli. Findings from the patient-specific optimization establish DynaRing's ability to adjust the anterior-posterior and intercommissural diameters and saddle height by up to 8.8%, 5.6%, 19.8%, respectively, and match a wide range of patient data.
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Affiliation(s)
- Samuel Frishman
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
| | - Ali Kight
- Department of Bioengineering, Stanford University, Stanford, CA 94305
| | - Ileana Pirozzi
- Department of Bioengineering, Stanford University, Stanford, CA 94305
| | | | | | | | - Michael J. Paulsen
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA 94305
| | | | - Y. Joseph Woo
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA 94305
| | - Mark R. Cutkosky
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
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Development of 3D Printed Mitral Valve Constructs for Transcatheter Device Modeling of Tissue and Device Deformation. Ann Biomed Eng 2022; 50:426-439. [PMID: 35220528 PMCID: PMC8917041 DOI: 10.1007/s10439-022-02927-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 02/06/2022] [Indexed: 11/29/2022]
Abstract
Transcatheter mitral valve repair (TMVR) therapies offer a minimally invasive alternative to surgical mitral valve (MV) repair for patients with prohibitive surgical risks. Pre-procedural planning and associated medical device modeling is primarily performed in silico, which does not account for the physical interactions between the implanted TMVR device and surrounding tissue and may result in poor outcomes. We developed 3D printed tissue mimics for modeling TMVR therapies. Structural properties of the mitral annuli, leaflets, and chordae were replicated from multi-material blends. Uniaxial tensile testing was performed on the resulting composites and their mechanical properties were compared to those of their target native components. Mimics of the MV annulus printed in homogeneous strips approximated the tangent moduli of the native mitral annulus at 2% and 6% strain. Mimics of the valve leaflets printed in layers of different stiffnesses approximated the force–strain and stress–strain behavior of native MV leaflets. Finally, mimics of the chordae printed as reinforced cylinders approximated the force–strain and stress–strain behavior of native chordae. We demonstrated that multi-material 3D printing is a viable approach to the development of tissue phantoms, and that printed patient-specific geometries can approximate the local deformation force which may act upon devices used for TMVR therapies.
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Zeng G, Li G, Jia Y, Chen S, Chen P, He Z. Detachment Force of the Helical Anchor in Mitral Annulus. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Miller R, Kerfoot E, Mauger C, Ismail TF, Young AA, Nordsletten DA. An Implementation of Patient-Specific Biventricular Mechanics Simulations With a Deep Learning and Computational Pipeline. Front Physiol 2021; 12:716597. [PMID: 34603077 PMCID: PMC8481785 DOI: 10.3389/fphys.2021.716597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/06/2021] [Indexed: 02/04/2023] Open
Abstract
Parameterised patient-specific models of the heart enable quantitative analysis of cardiac function as well as estimation of regional stress and intrinsic tissue stiffness. However, the development of personalised models and subsequent simulations have often required lengthy manual setup, from image labelling through to generating the finite element model and assigning boundary conditions. Recently, rapid patient-specific finite element modelling has been made possible through the use of machine learning techniques. In this paper, utilising multiple neural networks for image labelling and detection of valve landmarks, together with streamlined data integration, a pipeline for generating patient-specific biventricular models is applied to clinically-acquired data from a diverse cohort of individuals, including hypertrophic and dilated cardiomyopathy patients and healthy volunteers. Valve motion from tracked landmarks as well as cavity volumes measured from labelled images are used to drive realistic motion and estimate passive tissue stiffness values. The neural networks are shown to accurately label cardiac regions and features for these diverse morphologies. Furthermore, differences in global intrinsic parameters, such as tissue anisotropy and normalised active tension, between groups illustrate respective underlying changes in tissue composition and/or structure as a result of pathology. This study shows the successful application of a generic pipeline for biventricular modelling, incorporating artificial intelligence solutions, within a diverse cohort.
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Affiliation(s)
- Renee Miller
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Eric Kerfoot
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Charlène Mauger
- Auckland MR Research Group, University of Auckland, Auckland, New Zealand
| | - Tevfik F. Ismail
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Alistair A. Young
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Auckland MR Research Group, University of Auckland, Auckland, New Zealand
| | - David A. Nordsletten
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
- Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, MI, United States
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El-Tallawi KC, Zhang P, Azencott R, He J, Xu J, Herrera EL, Jacob J, Chamsi-Pasha M, Lawrie GM, Zoghbi WA. Mitral Valve Remodeling and Strain in Secondary Mitral Regurgitation: Comparison With Primary Regurgitation and Normal Valves. JACC Cardiovasc Imaging 2021; 14:782-793. [PMID: 33832661 DOI: 10.1016/j.jcmg.2021.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/12/2022]
Abstract
OBJECTIVES The aim of this study was to assess mitral valve (MV) remodeling and strain in patients with secondary mitral regurgitation (SMR) compared with primary MR (PMR) and normal valves. BACKGROUND A paucity of data exists on MV strain during the cardiac cycle in humans. Real-time 3-dimensional (3D) echocardiography allows for dynamic MV imaging, enabling computerized modeling of MV function in normal and disease states. METHODS Three-dimensional transesophageal echocardiography (TEE) was performed in a total of 106 subjects: 36 with SMR, 38 with PMR, and 32 with normal valves; MR severity was at least moderate in both MR groups. Valve geometric parameters were quantitated and patient-specific 3D MV models generated in systole using a dedicated software. Global and regional peak systolic MV strain was computed using a proprietary software. RESULTS MV annular area was larger in both the SMR and PMR groups (12.7 ± 0.7 and 13.3 ± 0.7 cm2, respectively) compared with normal subjects (9.9 ± 0.3 cm2; p < 0.05). The leaflets also had significant remodeling, with total MV leaflet area larger in both SMR (16.2 ± 0.9 cm2) and PMR (15.6 ± 0.8 cm2) versus normal subjects (11.6 ± 0.4 cm2). Leaflets in SMR were thicker than those in normal subjects but slightly less than those with PMR posteriorly. Posterior leaflet strain was significantly higher than anterior leaflet strain in all 3 groups. Despite MV remodeling, strain in SMR (8.8 ± 0.3%) was overall similar to normal subjects (8.5 ± 0.2%), and both were lower than in PMR (12 ± 0.4%; p < 0.0001). Valve thickness, severity of MR, and primary etiology of MR were correlates of strain, with leaflet thickness being the multivariable parameter significantly associated with MV strain. In patients with less severe MR, anterior leaflet strain in SMR was lower than normal, whereas strain in PMR remained higher than normal. CONCLUSIONS The MV in secondary MR remodels significantly and similarly to PMR with a resultant larger annular area, leaflet surface area, and leaflet thickness compared with that of normal subjects. Despite these changes, MV strain remains close to or in some instances lower than normal and is significantly lower than that of PMR. Strain determination has the potential to improve characterization of MV mechano-biologic properties in humans and to evaluate its prognostic impact in patients with MR, with or without valve interventions.
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Affiliation(s)
| | - Peng Zhang
- Department of Mathematics, University of Houston, Houston, Texas, USA
| | - Robert Azencott
- Department of Mathematics, University of Houston, Houston, Texas, USA
| | - Jiwen He
- Department of Mathematics, University of Houston, Houston, Texas, USA
| | - Jiaqiong Xu
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA; Center for Outcomes Research, Houston Methodist Research Institute, Houston, Texas, USA
| | - Elizabeth L Herrera
- Department of Anesthesiology, Division of Cardiovascular and Thoracic Anesthesiology, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA
| | - Jessen Jacob
- Maimonides Heart and Vascular Institute, Department of Cardiology, Brooklyn, New York, USA
| | | | - Gerald M Lawrie
- Department of Cardiovascular and Thoracic Surgery, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA
| | - William A Zoghbi
- Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA.
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8
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El-Tallawi KC, Zhang P, Azencott R, He J, Herrera EL, Xu J, Chamsi-Pasha M, Jacob J, Lawrie GM, Zoghbi WA. Valve Strain Quantitation in Normal Mitral Valves and Mitral Prolapse With Variable Degrees of Regurgitation. JACC Cardiovasc Imaging 2021; 14:1099-1109. [PMID: 33744129 DOI: 10.1016/j.jcmg.2021.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/15/2020] [Accepted: 01/06/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The aim of this study was to quantitate patient-specific mitral valve (MV) strain in normal valves and in patients with mitral valve prolapse with and without significant mitral regurgitation (MR) and assess the determinants of MV strain. BACKGROUND Few data exist on MV deformation during systole in humans. Three-dimensional echocardiography allows for dynamic MV imaging, enabling digital modeling of MV function in health and disease. METHODS Three-dimensional transesophageal echocardiography was performed in 82 patients, 32 with normal MV and 50 with mitral valve prolapse (MVP): 12 with mild mitral regurgitation or less (MVP - MR) and 38 with moderate MR or greater (MVP + MR). Three-dimensional MV models were generated, and the peak systolic strain of MV leaflets was computed on proprietary software. RESULTS Left ventricular ejection fraction was normal in all groups. MV annular dimensions were largest in MVP + MR (annular area: 13.8 ± 0.7 cm2) and comparable in MVP - MR (10.6 ± 1 cm2) and normal valves (10.5 ± 0.3 cm2; analysis of variance: p < 0.001). Similarly, MV leaflet areas were largest in MVP + MR, particularly the posterior leaflet (8.7 ± 0.5 cm2); intermediate in MVP - MR (6.5 ± 0.7 cm2); and smallest in normal valves (5.5 ± 0.2 cm2; p < 0.0001). Strain was overall highest in MVP + MR and lowest in normal valves. Patients with MVP - MR had intermediate strain values that were higher than normal valves in the posterior leaflet (p = 0.001). On multivariable analysis, after adjustment for clinical and MV geometric parameters, leaflet thickness was the only parameter that was retained as being significantly correlated with mean MV strain (r = 0.34; p = 0.008). CONCLUSIONS MVs that exhibit prolapse have higher strain compared to normal valves, particularly in the posterior leaflet. Although higher strain is observed with worsening MR and larger valves and annuli, mitral valve leaflet thickness-and, thus, underlying MV pathology-is the most significant independent determinant of valve deformation. Future studies are needed to assess the impact of MV strain determination on clinical outcome.
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Affiliation(s)
- K Carlos El-Tallawi
- Cardiovascular Imaging Institute, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA
| | - Peng Zhang
- Department of Mathematics, University of Houston, Houston, Texas, USA
| | - Robert Azencott
- Department of Mathematics, University of Houston, Houston, Texas, USA
| | - Jiwen He
- Department of Mathematics, University of Houston, Houston, Texas, USA
| | - Elizabeth L Herrera
- Department of Anesthesiology, Division of Cardiovascular and Thoracic Anesthesiology, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA
| | - Jiaqiong Xu
- Methodist DeBakey Heart and Vascular Center, Center for Outcomes Research, Houston Methodist Research Institute, Houston, Texas, USA
| | - Mohammed Chamsi-Pasha
- Cardiovascular Imaging Institute, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA
| | - Jessen Jacob
- Maimonides Heart and Vascular Institute, Department of Cardiology, Brooklyn, New York, USA
| | - Gerald M Lawrie
- Department of Cardiovascular and Thoracic Surgery, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA
| | - William A Zoghbi
- Cardiovascular Imaging Institute, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, USA.
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Noack T, Kiefer P, Vivell N, Sieg F, Marin-Cuartas M, Leontyev S, Holzhey DM, Garbade J, Pfannmueller B, Davierwala P, Misfeld M, Seeburger J, Borger MA. Annuloplasty ring dehiscence after mitral valve repair: incidence, localization and reoperation. Eur J Cardiothorac Surg 2020; 57:300-307. [PMID: 31369069 DOI: 10.1093/ejcts/ezz219] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/24/2019] [Accepted: 07/02/2019] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Mitral valve (MV) annuloplasty ring dehiscence with subsequent recurrent mitral regurgitation represents an unusual but challenging clinical problem. Incidence, localization and outcomes for this complication have not been well defined. METHODS From 1996 to 2016, a total of 3478 patients underwent isolated MV repair with ring annuloplasty at the Leipzig Heart Centre. Of these patients, 57 (1.6%) underwent reoperation due to annuloplasty ring dehiscence. Echocardiographic data, operative and early postoperative characteristics as well as short- and long-term survival rates after MV reoperation were analysed. RESULTS Occurrences of ring dehiscence were acute (<30 days), early (≤1 year) and late (>1 year) in 44%, 33% and 23% of patients, respectively. Localization of annuloplasty ring dehiscence was found most frequently in the P3 segment (68%), followed by the P2 (51%) and the P1 segments (47%). The 30-day mortality rate and 1- and 5-year survival rates after MV reoperation were 2%, 89% and 74%, respectively. During reoperation, MV replacement was performed in 38 (67%) and MV re-repair in 19 (33%) patients. CONCLUSIONS Annuloplasty ring dehiscence is clinically less common, localized more frequently on the posterior annulus and occurs mostly acutely or early after MV repair. MV reoperation can be performed safely in such patients.
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Affiliation(s)
- Thilo Noack
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Philipp Kiefer
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Nina Vivell
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Franz Sieg
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Mateo Marin-Cuartas
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Sergey Leontyev
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | | | - Jens Garbade
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Bettina Pfannmueller
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Piroze Davierwala
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Martin Misfeld
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Joerg Seeburger
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
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10
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Pierce EL, Kohli K, Ncho B, Sadri V, Bloodworth CH, Mangan FE, Yoganathan AP. Novel In Vitro Test Systems and Insights for Transcatheter Mitral Valve Design, Part II: Radial Expansion Forces. Ann Biomed Eng 2019; 47:392-402. [PMID: 30341736 PMCID: PMC6520998 DOI: 10.1007/s10439-018-02139-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/22/2018] [Indexed: 10/28/2022]
Abstract
Transcatheter mitral valve (TMV) replacement technology has great clinical potential for surgically inoperable patients suffering from mitral regurgitation. An important goal for robust TMV design is maximizing the likelihood of achieving a geometry post-implant that facilitates optimal performance. To support this goal, improved understanding of the annular forces that oppose TMV radial expansion is necessary. In Part II of this study, novel circular and D-shaped Radial Expansion Force Transducers (C-REFT and D-REFT) were developed and employed in porcine hearts (N = 12), to detect the forces required to radially expand the mitral annulus to discrete oversizing levels. Forces on both the septal-lateral and inter-commissural axes (FSL and FIC) scaled with device size. The D-REFT experienced lower FSL than the C-REFT (19.8 ± 7.4 vs. 17.4 ± 10.8 N, p = 0.002) and greater FIC (31.5 ± 14.0 vs. 36.9 ± 16.2 N; p = 0.002), and was more sensitive to degree of oversizing. Across all tests, FIC/FSL was 2.21 ± 1.33, likely reflecting low resistance to radial expansion at the aorto-mitral curtain. In conclusion, the annular forces opposing TMV radial expansion are non-uniform, and depend on final TMV shape and size. Based on this two-part study, we propose that radial force applied at the commissural aspect of the annulus has the most potent effect on paravalvular sealing.
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Affiliation(s)
- Eric L Pierce
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA
| | - Keshav Kohli
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA
| | - Beatrice Ncho
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA
| | - Vahid Sadri
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA
| | - Charles H Bloodworth
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA
| | - Fiona E Mangan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA
| | - Ajit P Yoganathan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA.
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11
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Calafiore AM, Totaro A, Foschi M, Di Mauro M. Durability of mitral valve repair for degenerative mitral regurgitation: is it gold all that glitters? ANNALS OF TRANSLATIONAL MEDICINE 2019; 6:S10. [PMID: 30613586 DOI: 10.21037/atm.2018.08.43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Antonio M Calafiore
- Department of Cardiac Surgery and Cardiology, Pope John Paul II Foundation, Campobasso, Italy
| | - Antonio Totaro
- Department of Cardiac Surgery and Cardiology, Pope John Paul II Foundation, Campobasso, Italy
| | | | - Michele Di Mauro
- Cardiac Surgery and Cardiology, API Madonna del Ponte, Lanciano, Italy
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12
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Mitral annuloplasty ring flexibility preferentially reduces posterior suture forces. J Biomech 2018; 75:58-66. [PMID: 29747965 DOI: 10.1016/j.jbiomech.2018.04.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 11/20/2022]
Abstract
Annuloplasty ring repair is a common procedure for the correction of mitral valve regurgitation. Commercially available rings vary in dimensions and material properties. Annuloplasty ring suture dehiscence from the native annulus is a catastrophic yet poorly understood phenomenon that has been reported across ring types. Recognizing that sutures typically dehisce from the structurally weaker posterior annulus, our group is conducting a multi-part study in search of ring design parameters that influence forces acting on posterior annular sutures in the beating heart. Herein, we report the effect of ring rigidity on suture forces. Measurements utilized custom force sensors, attached to annuloplasty rings and implanted in normal ovine subjects via standard surgical procedure. Tested rings included the semi-rigid Physio (Edwards Lifesciences) and rigid and flexible prototypes of matching geometry. While no significant differences due to ring stiffness existed for sutures in the anterior region, posterior forces were significantly reduced with use of the flexible ring (rigid: 1.95 ± 0.96 N, semi-rigid: 1.76 ± 1.19 N, flexible: 1.04 ± 0.63 N; p < 0.001). The ratio of anterior to posterior FC scaled positively with increasing flexibility (p < 0.001), and posterior forces took more time to reach their peak load when a flexible ring was used (p < 0.001). This suggests a more rigid ring enables more rapid/complete force equilibration around the suture network, transferring higher anterior forces to the weaker posterior tissue. For mitral annuloplasties requiring ring rigidity, we propose a ring design concept to potentially disrupt this force transfer and improve suture retention.
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Basu A, Lacerda C, He Z. Mechanical Properties and Composition of the Basal Leaflet-Annulus Region of the Tricuspid Valve. Cardiovasc Eng Technol 2018; 9:217-225. [DOI: 10.1007/s13239-018-0343-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 02/19/2018] [Indexed: 10/17/2022]
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14
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Liang JJ, Silvestry FE. Mechanistic insights into mitral regurgitation due to atrial fibrillation: “Atrial functional mitral regurgitation”. Trends Cardiovasc Med 2016; 26:681-689. [DOI: 10.1016/j.tcm.2016.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
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15
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Pierce EL, Siefert AW, Paul DM, Wells SK, Bloodworth CH, Takebayashi S, Aoki C, Jensen MO, Gillespie MJ, Gorman RC, Gorman JH, Yoganathan AP. How Local Annular Force and Collagen Density Govern Mitral Annuloplasty Ring Dehiscence Risk. Ann Thorac Surg 2016; 102:518-26. [PMID: 27133454 DOI: 10.1016/j.athoracsur.2016.01.107] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 11/28/2015] [Accepted: 01/28/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Annuloplasty ring dehiscence is a well described mode of mitral valve repair failure. Defining the mechanisms underlying dehiscence may facilitate its prevention. METHODS Factors that govern suture dehiscence were examined with an ovine model. After undersized ring annuloplasty in live animals (n = 5), cyclic force (FC) that acts on sutures during cardiac contraction was measured with custom transducers. FC was measured at ten suture positions, throughout cardiac cycles with peak left ventricular pressure (LVPmax) of 100, 125, and 150 mm Hg. Suture pullout testing was conducted on explanted mitral annuli (n = 12) to determine suture holding strength at each position. Finally, relative collagen density differences at suture sites around the annulus were assessed by two-photon excitation fluoroscopy. RESULTS Anterior FC exceeded posterior FC at each LVPmax (eg, 2.8 ± 1.3 N versus 1.8 ± 1.2 N at LVPmax = 125 mm Hg, p < 0.01). Anterior holding strength exceeded posterior holding strength (6.4 ± 3.6 N versus 3.9 ± 1.6 N, p < 0.0001). On the basis of FC at LVPmax of 150 mm Hg, margin of safety before suture pullout was vastly higher between the trigones (exclusive) versus elsewhere (4.8 ± 0.9 N versus 1.9 ± 0.5 N, p < 0.001). Margin of safety exhibited strong correlation to collagen density (R(2) = 0.947). CONCLUSIONS Despite lower cyclic loading on posterior sutures, the weaker posterior mitral annular tissue creates higher risk of dehiscence, apparently because of reduced collagen content. Sutures placed atop the trigones are less secure than predicted, because of a combination of reduced collagen and higher overall rigidity in this region. These findings highlight the inter-trigonal tissue as the superior anchor and have implications on the design and implantation techniques for next-generation mitral prostheses.
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Affiliation(s)
- Eric L Pierce
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Andrew W Siefert
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Deborah M Paul
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Sarah K Wells
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Charles H Bloodworth
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Satoshi Takebayashi
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chikashi Aoki
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Morten O Jensen
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Matthew J Gillespie
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ajit P Yoganathan
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
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Pierce EL, Gentile J, Siefert AW, Gorman RC, Gorman JH, Yoganathan AP. Real-time recording of annuloplasty suture dehiscence reveals a potential mechanism for dehiscence cascade. J Thorac Cardiovasc Surg 2016; 152:e15-7. [PMID: 26971379 DOI: 10.1016/j.jtcvs.2016.01.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/07/2016] [Accepted: 01/23/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Eric L Pierce
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga
| | - Javier Gentile
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | | | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Ajit P Yoganathan
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Ga.
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17
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New mitral annular force transducer optimized to distinguish annular segments and multi-plane forces. J Biomech 2016; 49:742-748. [DOI: 10.1016/j.jbiomech.2016.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/08/2015] [Accepted: 02/03/2016] [Indexed: 11/22/2022]
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18
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Ben Zekry S, Freeman J, Jajoo A, He J, Little SH, Lawrie GM, Azencott R, Zoghbi WA. Patient-Specific Quantitation of Mitral Valve Strain by Computer Analysis of Three-Dimensional Echocardiography. Circ Cardiovasc Imaging 2016; 9:CIRCIMAGING.115.003254. [DOI: 10.1161/circimaging.115.003254] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Sagit Ben Zekry
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - Jeff Freeman
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - Aarti Jajoo
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - Jiwen He
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - Stephen H. Little
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - Gerald M. Lawrie
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - Robert Azencott
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
| | - William A. Zoghbi
- From the Echocardiography Department (S.B.Z., S.H.L., W.A.Z.) and Department of Cardiovascular and Thoracic Surgery (G.M.L.), Houston Methodist DeBakey Heart and Vascular Center, TX; Department of Cardiology, Non Invasive Cardiology Unit, Affiliated with the Leviev Heart Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel (S.B.Z.); and Department of Mathematics, University of Houston, TX (J.F., A.J., J.H., R.A.)
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Characterisation of the fatigue life, dynamic creep and modes of damage accumulation within mitral valve chordae tendineae. Acta Biomater 2015; 24:193-200. [PMID: 26087111 DOI: 10.1016/j.actbio.2015.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 06/01/2015] [Accepted: 06/10/2015] [Indexed: 11/21/2022]
Abstract
Mitral valve prolapse is often caused by either elongated or ruptured chordae tendineae (CT). In many cases, rupture is spontaneous, meaning there is no underlying cause. We hypothesised that spontaneous rupture may be due to mechanical fatigue. To investigate this hypothesis, we tested porcine marginal CT: in uniaxial tension, and in fatigue at a range of peak stresses (n=12 at 15, 10 and 7.5MPa respectively, n=6 at 5MPa). The rupture surfaces of failed CT were observed histologically, under polarised light microscopy, and SEM. The cycles to failure for 15, 10, 7.5 and 5 MPa peak stresses were: (average±SD): 5077±4366, 49513±56414, 99927±108908, 197099±69103. A Weibull plot was constructed and from this, the number of cycles at 50% probability of failure was established in order to approximate the fatigue life, which was found to be 2.43MPa at 10 million cycles. The rate of creep increases exponentially with increasing peak stress. Under histological examination it was observed that CT which have been fatigued at low stress partially lose their organised collagen structure and can sustain micro-cracks that can be linked to increases in the creep rate. Furthermore our SEM images closely matched descriptions from the literature of spontaneous in vivo rupture. In conclusion, we believe that the mechanical test results we present strongly suggest that spontaneous chordal rupture and chordal elongation in vivo can be caused by mechanical fatigue.
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Hagège AA, Carpentier A, Levine RA. Dynamic changes of the mitral valve annulus: new look at mitral valve diseases. Circ Cardiovasc Imaging 2015; 8:CIRCIMAGING.115.003539. [PMID: 25956923 DOI: 10.1161/circimaging.115.003539] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Albert A Hagège
- From the Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France (A.A.H., A.C., R.A.L.); INSERM U970, Paris Cardiovascular Research Center, Hôpital Européen Georges Pompidou, Paris, France (A.A.H.); Department of Cardiology (A.A.H.) and Department of Cardiovascular Surgery (A.C.), Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France; and Cardiac Ultrasound Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, MA (R.A.L.).
| | - Alain Carpentier
- From the Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France (A.A.H., A.C., R.A.L.); INSERM U970, Paris Cardiovascular Research Center, Hôpital Européen Georges Pompidou, Paris, France (A.A.H.); Department of Cardiology (A.A.H.) and Department of Cardiovascular Surgery (A.C.), Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France; and Cardiac Ultrasound Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, MA (R.A.L.)
| | - Robert A Levine
- From the Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France (A.A.H., A.C., R.A.L.); INSERM U970, Paris Cardiovascular Research Center, Hôpital Européen Georges Pompidou, Paris, France (A.A.H.); Department of Cardiology (A.A.H.) and Department of Cardiovascular Surgery (A.C.), Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France; and Cardiac Ultrasound Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, MA (R.A.L.)
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