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Liu H, Sacks MS, Simonian NT, Gorman JH, Gorman RC. Simulated Effects of Acute Left Ventricular Myocardial Infarction on Mitral Regurgitation in an Ovine Model. J Biomech Eng 2024; 146:101009. [PMID: 38652602 DOI: 10.1115/1.4065376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Ischemic mitral regurgitation (IMR) occurs from incomplete coaptation of the mitral valve (MV) after myocardial infarction (MI), typically worsened by continued remodeling of the left ventricular (LV). The importance of LV remodeling is clear as IMR is induced by the post-MI dual mechanisms of mitral annular dilation and leaflet tethering from papillary muscle (PM) distension via the MV chordae tendineae (MVCT). However, the detailed etiology of IMR remains poorly understood, in large part due to the complex interactions of the MV and the post-MI LV remodeling processes. Given the patient-specific anatomical complexities of the IMR disease processes, simulation-based approaches represent an ideal approach to improve our understanding of this deadly disease. However, development of patient-specific models of left ventricle-mitral valve (LV-MV) interactions in IMR are complicated by the substantial variability and complexity of the MR etiology itself, making it difficult to extract underlying mechanisms from clinical data alone. To address these shortcomings, we developed a detailed ovine LV-MV finite element (FE) model based on extant comprehensive ovine experimental data. First, an extant ovine LV FE model (Sci. Rep. 2021 Jun 29;11(1):13466) was extended to incorporate the MV using a high fidelity ovine in vivo derived MV leaflet geometry. As it is not currently possible to image the MVCT in vivo, a functionally equivalent MVCT network was developed to create the final LV-MV model. Interestingly, in pilot studies, the MV leaflet strains did not agree well with known in vivo MV leaflet strain fields. We then incorporated previously reported MV leaflet prestrains (J. Biomech. Eng. 2023 Nov 1;145(11):111002) in the simulations. The resulting LV-MV model produced excellent agreement with the known in vivo ovine MV leaflet strains and deformed shapes in the normal state. We then simulated the effects of regional acute infarctions of varying sizes and anatomical locations by shutting down the local myocardial contractility. The remaining healthy (noninfarcted) myocardium mechanical behaviors were maintained, but allowed to adjust their active contractile patterns to maintain the prescribed pressure-volume loop behaviors in the acute post-MI state. For all cases studied, the LV-MV simulation demonstrated excellent agreement with known LV and MV in vivo strains and MV regurgitation orifice areas. Infarct location was shown to play a critical role in resultant MV leaflet strain fields. Specifically, extensional deformations of the posterior leaflets occurred in the posterobasal and laterobasal infarcts, while compressive deformations of the anterior leaflet were observed in the anterobasal infarct. Moreover, the simulated posterobasal infarct induced the largest MV regurgitation orifice area, consistent with experimental observations. The present study is the first detailed LV-MV simulation that reveals the important role of MV leaflet prestrain and functionally equivalent MVCT for accurate predictions of LV-MV interactions. Importantly, the current study further underscored simulation-based methods in understanding MV function as an integral part of the LV.
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Affiliation(s)
- Hao Liu
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, The Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, The Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Natalie T Simonian
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, The Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, University of Pennsylvania, Philadelphia, PA 19146-2701
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, University of Pennsylvania, Philadelphia, PA 19146-2701
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Mora V, Geraldo J, Roldán I, Galiana E, Gil C, Escribano P, Arbucci R, Hidalgo A, Gramage P, Trainini J, Carreras F, Lowenstein J. A New Coding System for the Identification of Left Ventricular Rotation Patterns and Their Relevance to Myocardial Function. Ann Biomed Eng 2024:10.1007/s10439-024-03539-4. [PMID: 38853207 DOI: 10.1007/s10439-024-03539-4] [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: 01/08/2024] [Accepted: 04/25/2024] [Indexed: 06/11/2024]
Abstract
Rotational mechanics is a fundamental determinant of left ventricular ejection fraction (LVEF). The coding system currently employed in clinical practice does not distinguish between rotational patterns. We propose an alternative coding system that makes possible to identify the rotational pattern of the LV and relate it to myocardial function. Echocardiographic images were used to generate speckle tracking-derived transmural global longitudinal strain (tGLS) and rotational parameters. The existence of twist (basal and apical rotations in opposite directions) is expressed as a rotational gradient with a positive value that is the sum of the basal and apical rotation angles. Conversely, when there is rigid rotation (basal and apical rotations in the same direction) the resulting gradient is assigned a negative value that is the subtraction between the two rotation angles. The rotational patterns were evaluated in 87 healthy subjects and 248 patients with LV hypertrophy (LVH) and contrasted with their myocardial function. Our approach allowed us to distinguish between the different rotational patterns. Twist pattern was present in healthy controls and 104 patients with LVH and normal myocardial function (tGLS ≥ 17%, both). Among 144 patients with LVH and myocardial dysfunction (tGLS < 17%), twist was detected in 83.3% and rigid rotation in 16.7%. LVEF was < 50% in 34.7%, and all patients with rigid rotation had a LVEF < 50%. The gradient rotational values showed a close relationship with LVEF (r = 0.73; p < 0.001). The proposed coding system allows us to identify the rotational patterns of the LV and to relate their values with LVEF.
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Affiliation(s)
- Vicente Mora
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Juan Geraldo
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Ildefonso Roldán
- Cardiology Department, Universitat de València, Hospital Universitario Dr Peset, Avda Gaspar Aguilar 90, 46017, Valencia, Spain.
| | - Ester Galiana
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Celia Gil
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Pablo Escribano
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Rosina Arbucci
- Cardiodiagnosis Department, Medical Research, 1425, Buenos Aires, Argentina
| | - Alberto Hidalgo
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Paula Gramage
- Department of Cardiology, Hospital Universitario Dr Peset, 46017, Valencia, Spain
| | - Jorge Trainini
- Cardiodiagnosis Department, Medical Research, 1425, Buenos Aires, Argentina
| | - Francesc Carreras
- Department of Cardiology, Hospital Sant Pau, 08025, Barcelona, Spain
| | - Jorge Lowenstein
- Cardiodiagnosis Department, Medical Research, 1425, Buenos Aires, Argentina
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3
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Jedrzejczyk JH, Krog S, Skov SN, Poulsen KB, Sharghbin M, Benhassen LL, Nielsen SL, Hasenkam JM, Tjørnild MJ. Entire Mitral Valve Reconstruction Using Porcine Extracellular Matrix: Adding a Ring Annuloplasty. Cardiovasc Eng Technol 2024:10.1007/s13239-024-00727-0. [PMID: 38504076 DOI: 10.1007/s13239-024-00727-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/10/2024] [Indexed: 03/21/2024]
Abstract
PURPOSE This study investigated the implications of inserting a flexible annuloplasty ring after reconstructing the entire mitral valve in a porcine model using a previously investigated tube graft design made of 2-ply small intestinal submucosa extracellular matrix (CorMatrix®). METHODS An acute model with eight 80-kg pigs, each acting as its own control, was used. The entire mitral valve was reconstructed with a 2-ply small intestinal submucosa extracellular matrix tube graft (CorMatrix®). Subsequently, a Simulus® flexible ring was inserted. The characterization was based on mitral annular geometry and valvular dynamics with sonomicrometry and echocardiography. RESULTS After adding the ring annuloplasty, the in-plane annular dynamics were more constant throughout the cardiac cycle compared to the reconstruction alone. However, the commissure-commissure distance was statistically significantly decreased [35.0 ± 3.4 mm vs. 27.4 ± 1.9 mm, P < 0.001, diff = - 7.6 mm, 95% CI, - 9.8 to (-5.4) mm] after ring insertion, changing the physiological annular D-shape into a circular shape which created folds at the coaptation zone resulting in a central regurgitant jet on color Doppler. CONCLUSION We successfully reconstructed the entire mitral valve using 2-ply small intestinal submucosal extracellular matrix (CorMatrix®) combined with a flexible annuloplasty. The annuloplasty reduced the unphysiological systolic widening previously found with this reconstructive technique. However, the Simulus flex ring changed the physiological annular D-shape into a circular shape and hindered a correct unfolding of the leaflets. Thus, we do not recommend a flexible ring in conjunction with this reconstructive technique; further investigations are needed to discover a more suitable remodelling annuloplasty.
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Affiliation(s)
- Johannes H Jedrzejczyk
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark.
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark.
| | - Stine Krog
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
| | - Søren N Skov
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
| | - Karen B Poulsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
| | - Mona Sharghbin
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
| | - Leila L Benhassen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
| | - Sten L Nielsen
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
| | - J Michael Hasenkam
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
- Department of Surgery, University of the Witwatersrand, Johannesburg, South Africa
| | - Marcell J Tjørnild
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Århus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Århus, Denmark
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Persson RM, Aguilera HMD, Kvitting JE, Grong K, Prot VE, Salminen P, Svenheim B, Leiknes A, Stangeland L, Haaverstad R, Urheim S. Mitral annular dynamics are influenced by left ventricular load and contractility in an acute animal model. Physiol Rep 2023; 11:e15665. [PMID: 37062589 PMCID: PMC10106308 DOI: 10.14814/phy2.15665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 04/18/2023] Open
Abstract
The purpose of this study was to investigate the effects of loading conditions and left ventricular (LV) contractility on mitral annular dynamics. In 10 anesthetized pigs, eight piezoelectric transducers were implanted equidistantly around the mitral annulus. High-fidelity catheters measured left ventricular pressures and the slope of the end-systolic pressure-volume relationship (Ees ) determined LV contractility. Adjustments of pre- and afterload were done by constriction of the inferior caval vein and occlusion of the descending aorta. Mitral annulus area indexed to body surface area (MAAi ), annular circularity index (ACI), and non-planarity angle (NPA) were calculated by computational analysis. MAAi was more dynamic in response to loading interventions than ACI and NPA. However, MAAi maximal cyclical reduction (-Δr) and average deformational velocity (-v ¯ $$ \overline{v} $$ ) did not change accordingly (p = 0.31 and p = 0.22). Reduced Ees was associated to attenuation in MAAi -Δr and MAAi -v ¯ $$ \overline{v} $$ (r2 = 0.744; p = 0.001 and r2 = 0.467; p = 0.029). In conclusion, increased cardiac load and reduced LV contractility may cause deterioration of mitral annular dynamics, likely impairing coaptation and increasing susceptibility to valvular incompetence.
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Affiliation(s)
- Robert Matongo Persson
- Department of Heart DiseaseHaukeland University HospitalBergenNorway
- Department of Clinical Science, Faculty of MedicineUniversity of BergenBergenNorway
| | - Hans Martin Dahl Aguilera
- Department of Structural Engineering, Faculty of Engineering ScienceThe Norwegian University of Science and TechnologyTrondheimNorway
| | - John‐Peder Escobar Kvitting
- Department of Cardiothoracic SurgeryOslo University Hospital, RikshospitaletOsloNorway
- Institute of Clinical MedicineUniversity of OsloOsloNorway
| | - Ketil Grong
- Department of Clinical Science, Faculty of MedicineUniversity of BergenBergenNorway
| | - Victorien Emile Prot
- Department of Structural Engineering, Faculty of Engineering ScienceThe Norwegian University of Science and TechnologyTrondheimNorway
| | | | - Bård Svenheim
- Department of Heart DiseaseHaukeland University HospitalBergenNorway
| | - Anita Leiknes
- Department of Heart DiseaseHaukeland University HospitalBergenNorway
| | - Lodve Stangeland
- Department of Clinical Science, Faculty of MedicineUniversity of BergenBergenNorway
| | - Rune Haaverstad
- Department of Heart DiseaseHaukeland University HospitalBergenNorway
- Department of Clinical Science, Faculty of MedicineUniversity of BergenBergenNorway
| | - Stig Urheim
- Department of Heart DiseaseHaukeland University HospitalBergenNorway
- Department of Clinical Science, Faculty of MedicineUniversity of BergenBergenNorway
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Horgan CO, Murphy JG. The effect of fiber-matrix interaction on the kinking instability arising in the torsion of stretched fibrous biofilaments. J Mech Behav Biomed Mater 2021; 124:104782. [PMID: 34536799 DOI: 10.1016/j.jmbbm.2021.104782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/03/2021] [Accepted: 08/13/2021] [Indexed: 10/20/2022]
Abstract
The response of fibrous soft tissues undergoing torsional deformations is a topic of current interest. Such deformations are common in ligaments and tendons and are also of particular interest in cardiac mechanics. The problem of torsion superimposed on extension of incompressible hyperelastic solid circular cylinders is a classic problem of nonlinear elasticity that has been considered by many authors in the context of rubber elasticity particularly for isotropic materials. A striking feature of such problems is the instability that arises with sufficiently large twist where a kink and then a knot suddenly appears. An energy approach to examining this instability when the extension and twist are prescribed was described by Gent and Hua (2004) and illustrated there for a neo-Hookean isotropic elastic material. The theoretical results were compared with experimental observations on natural rubber rods. Murphy (2015) has shown that the approach of Gent and Hua (2004) for isotropic materials can be simplified when the rods are assumed to be thin and this theory was applied to transversely isotropic materials by Horgan and Murphy (2016). In contrast with the case for isotropic materials, it was shown there that the kinking instability occurs even in the absence of stretch, i.e., for the case of pure torsion. Here we are concerned with the implications of this simplified thin rod instability theory for fiber-reinforced transversely isotropic materials that reflect fiber-matrix interaction. It is again shown that the kinking instability occurs even in the absence of stretch, i.e., for the case of pure torsion. The results are illustrated for a specific strain-energy density function that models fiber-matrix interaction. It is shown that the critical twist at which kinking occurs decreases as a measure of fiber-matrix interaction is increased so that the fiber-matrix interaction has a destabilizing effect. The results are illustrated using experimental data of other authors for skeletal muscles and for porcine brain white matter tissue.
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Affiliation(s)
- Cornelius O Horgan
- School of Engineering and Applied Science, University of Virginia, Charlottesville, VA, 22904, USA.
| | - Jeremiah G Murphy
- Department of Mechanical Engineering, Dublin City University, Glasnevin, Dublin, D09 W6Y4, Ireland.
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6
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Tjørnild MJ, Carlson Hanse L, Skov SN, Poulsen KB, Sharghbin M, Benhassen LL, Røpcke DM, Nielsen SL, Hasenkam JM. Annular and subvalvular dynamics after extracellular matrix mitral tube graft implantation in pigs. Interact Cardiovasc Thorac Surg 2021; 32:978-987. [PMID: 33595082 DOI: 10.1093/icvts/ivab027] [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: 07/19/2020] [Revised: 11/24/2020] [Accepted: 12/20/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Entire mitral valve reconstruction with an extracellular matrix tube graft is a potential candidate to overcome the current limitations of mechanical and bioprosthetic valves. However, clinical data have raised concern with respect to patch failure. The aim of our study was to evaluate the impact of extracellular matrix mitral tube graft implantation on mitral annular and subvalvular regional dynamics in pigs. METHODS A modified tube graft design made of 2-ply extracellular matrix was used (CorMatrix®; Cardiovascular Inc., Alpharetta, GA, USA). The reconstructions were performed in an acute 80-kg porcine model (N = 8), where each pig acted as its own control. Haemodynamics were assessed with Mikro-Tip pressure catheters and mitral annular and subvalvular geometry and dynamics with sonomicrometry. RESULTS Catheter-based peak left atrial pressure and pressure difference across the mitral and aortic valves in the reconstructions were comparable to the values seen in the native mitral valves. Also comparable were maximum mitral annular area (755 ± 100 mm2), maximum septal-lateral distance (29.7 ± 1.7 mm), maximum commissure-commissure distance (35.0 ± 3.4 mm), end-systolic annular height-to-commissural width ratio (10.2 ± 1.0%) and end-diastolic interpapillary muscle distance (27.7 ± 3.3 mm). Systolic expansion of the mitral annulus was, however, observed after reconstruction. CONCLUSIONS The reconstructed mitral valves were fully functional without regurgitation, obstruction or stenosis. The reconstructed mitral annular and subvalvular geometry and subvalvular dynamics were found in the same range to those in the native mitral valve. A regional annular ballooning effect occurred that might predispose to patch failure. However, the greatest risk was found at the papillary muscle attachments.
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Affiliation(s)
- Marcell J Tjørnild
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Orthopaedic Surgery, Randers Regional Hospital, Denmark
| | - Lisa Carlson Hanse
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Søren N Skov
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Karen B Poulsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mona Sharghbin
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Leila L Benhassen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Diana M Røpcke
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Sten L Nielsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - J Michael Hasenkam
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Surgery, University of the Witwatersrand, Johannesburg, South Africa
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7
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Aly AH, Aly AH, Lai EK, Yushkevich N, Stoffers RH, Gorman JH, Cheung AT, Gorman JH, Gorman RC, Yushkevich PA, Pouch AM. In Vivo Image-Based 4D Modeling of Competent and Regurgitant Mitral Valve Dynamics. EXPERIMENTAL MECHANICS 2021; 61:159-169. [PMID: 33776070 PMCID: PMC7988343 DOI: 10.1007/s11340-020-00656-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 08/05/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND In vivo characterization of mitral valve dynamics relies on image analysis algorithms that accurately reconstruct valve morphology and motion from clinical images. The goal of such algorithms is to provide patient-specific descriptions of both competent and regurgitant mitral valves, which can be used as input to biomechanical analyses and provide insights into the pathophysiology of diseases like ischemic mitral regurgitation (IMR). OBJECTIVE The goal is to generate accurate image-based representations of valve dynamics that visually and quantitatively capture normal and pathological valve function. METHODS We present a novel framework for 4D segmentation and geometric modeling of the mitral valve in real-time 3D echocardiography (rt-3DE), an imaging modality used for pre-operative surgical planning of mitral interventions. The framework integrates groupwise multi-atlas label fusion and template-based medial modeling with Kalman filtering to generate quantitatively descriptive and temporally consistent models of valve dynamics. RESULTS The algorithm is evaluated on rt-3DE data series from 28 patients: 14 with normal mitral valve morphology and 14 with severe IMR. In these 28 data series that total 613 individual 3DE images, each 3D mitral valve segmentation is validated against manual tracing, and temporal consistency between segmentations is demonstrated. CONCLUSIONS Automated 4D image analysis allows for reliable non-invasive modeling of the mitral valve over the cardiac cycle for comparison of annular and leaflet dynamics in pathological and normal mitral valves. Future studies can apply this algorithm to cardiovascular mechanics applications, including patient-specific strain estimation, fluid dynamics simulation, inverse finite element analysis, and risk stratification for surgical treatment.
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Affiliation(s)
- A H Aly
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - A H Aly
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - E K Lai
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - N Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - J H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - A T Cheung
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University Medical Center, Stanford, CA, USA
| | - J H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - R C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - P A Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - A M Pouch
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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8
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Poulsen KB, Tjørnild MJ, Skov SN, Sharghbin M, Hanse LC, Benhassen LL, Røpcke DM, Nielsen SL, Hasenkam JM. Annular Dynamics and Leaflet Geometry in Patch Reconstruction of the Posterior Mitral Leaflet After Adding a Flexible Annuloplasty Ring. Cardiovasc Eng Technol 2020; 11:748-759. [PMID: 33200342 DOI: 10.1007/s13239-020-00502-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/05/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE Patch reconstruction of the posterior mitral leaflet using small intestinal submucosa extracellular matrix has been successfully performed in a porcine study. The patch reconstruction, however, resulted in non-physiological systolic widening of the mitral annulus, suggesting the need for an annuloplasty ring. The objective was to characterize the impact on annular dynamics and leaflet geometry of adding a flexible annuloplasty ring to the posterior mitral leaflet patch reconstruction. METHODS Measurements were performed in an acute 80-kg porcine model, with seven pigs acting as their own controls. The posterior mitral leaflet was reconstructed with a 2-ply small intestinal submucosa extracellular matrix patch (CorMatrix®). Additionally, a Simulus® Flexible Annuloplasty Ring (Medtronic Inc., Minneapolis, MN, USA) was inserted. Mitral annular dynamics were evaluated using sonomicrometry, and leaflet geometry was described using echocardiography. RESULTS The annuloplasty ring reduced mitral annular dimensions and restricted cyclic changes in mitral annular area (126 ± 19 vs. 30 ± 13 mm2, p < 0.001), septal-lateral and commisure-commisure distances. Ring annuloplasty prevented systolic widening in the mitral annulus after posterior mitral leaflet reconstruction. The annular saddle shape and leaflet coaptation length (8.7 ± 2.3 vs. 9.7 ± 1.3 mm, p = 0.221) were comparable before and after ring insertion. CONCLUSIONS The flexible annuloplasty ring resulted in a downsized annulus with restriction of cyclic annular changes in the reconstructed mitral valve. Ring insertion preserved the annular saddle shape and coaptation length. The ring annuloplasty counteracted the non-physiological annular dynamics, and this may improve durability of the posterior mitral leaflet patch reconstruction.
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Affiliation(s)
- Karen B Poulsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark.
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - Marcell J Tjørnild
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Søren N Skov
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mona Sharghbin
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Lisa Carlson Hanse
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Leila L Benhassen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Diana M Røpcke
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Sten L Nielsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - J Michael Hasenkam
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Palle Juul-Jensens, Boulevard 99, 8200, Aarhus N, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
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Avazmohammadi R, Soares JS, Li DS, Eperjesi T, Pilla J, Gorman RC, Sacks MS. On the in vivo systolic compressibility of left ventricular free wall myocardium in the normal and infarcted heart. J Biomech 2020; 107:109767. [PMID: 32386714 PMCID: PMC7433024 DOI: 10.1016/j.jbiomech.2020.109767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/26/2020] [Indexed: 01/01/2023]
Abstract
Although studied for many years, there remain continued gaps in our fundamental understanding of cardiac kinematics, such as the nature and extent of heart wall volumetric changes that occur over the cardiac cycle. Such knowledge is especially important for accurate in silico simulations of cardiac pathologies and in the development of novel therapies for their treatment. A prime example is myocardial infarction (MI), which induces profound, regionally variant maladaptive remodeling of the left ventricle (LV) wall. To address this problem, we conducted an in vivo fiduciary marker-based study in an established ovine model of MI to generate detailed, time-evolving transmural in vivo volumetric measurements of LV free wall deformations in the normal state, as well as up to 12 h post-MI. This was accomplished using a transmural array of sonomicrometry crystals that acquired fiducial positions at ∼250 Hz with a positional accuracy of ∼0.1 mm, covering the entire infarct, border, and remote zones. A convex-hull method was used to directly calculate the Jacobian J(t)=Δv(t)/ΔVED from sonocrystal positions over the entire cardiac cycle, where ΔV is the volume of each convex polyhedral at end diastole (ED) (typically ∼1 cc). We demonstrated significant in vivo compressibility in normal functioning LV free wall myocardium, with JES=0.85±0.07 at end systole (ES). We also observed substantial regional variations, with the largest reduction in local myocardial tissue volume during systole in the base region accompanied by substantial transmural gradients. These patterns changed profoundly following loss of perfusion post-MI, with the apical region showing the greatest loss of volume reduction at ES. To verify that the sonocrystals did not affect local volumetric measurements, JES measures were also verified by non-invasive magnetic resonance imaging, exhibiting very similar changes in regional volume. We note that while our estimates of regional compressibility were in close agreement with the values previously reported for large animals, ranging from 5% to 20%, the direct, comprehensive measurements of wall compressibility presented herein improved on the limitations of previous reports. These limitations included dependency on the small local volumes used for analysis and often indirect measurement of compressibility. Our novel findings suggest that proper accounting for the myocardial effective compressibility at the ∼1 cc volume scale can improve the accuracy of existing kinematic indices, such as wall thickening and axial shortening, and simulations of LV remodeling following MI.
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Affiliation(s)
- Reza Avazmohammadi
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA; Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Joao S Soares
- Department of Mechanical and Nuclear Engineering, Virginia Commonweath University, Richmond VA 23284, USA
| | - David S Li
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Thomas Eperjesi
- Gorman Cardiovascular Research Group, Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Pilla
- Gorman Cardiovascular Research Group, Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, Department of Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
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10
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Silbiger JJ, Bazaz R. The anatomic substrate of mitral annular contraction. Int J Cardiol 2020; 306:158-161. [DOI: 10.1016/j.ijcard.2019.11.129] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/05/2019] [Accepted: 11/21/2019] [Indexed: 11/25/2022]
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11
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Azar T, McLennan S, Walsh M, Angeles J, Kövecses J, Jaramillo T, Mongrain R, Cecere R. Dynamic Left Atrioventricular Phantom Test Bed Emulating Mitral Valve Motion. J Med Device 2020. [DOI: 10.1115/1.4046862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Abstract
Novel catheter-based medical procedures targeting heart valve structures are currently under development. These techniques entail installing a prosthetic implant on valves inside a beating heart. The development of these approaches requires a simple and effective validation test bed. Current early process testing methods rely on both static and dynamically pressurized excised porcine hearts. The variability between excised-tissue mechanical properties poses problems of reproducibility. In addition, these test beds do not emulate annulus motion, which affects the implant installation. A reproducible phantom of the left atrioventricular chambers was developed. The system consists of a hydraulic constant flow arrangement and a polyvinyl alcohol phantom heart with material properties that mimic passive myocardium mechanical properties and annulus motion. The system was then used to emulate blood flow through an actual heart. The building process starts by obtaining an accurate computer-aided design (CAD) model of a human heart, from which, a mold is produced using a novel rapid-freezing prototyping method and computer numerical control machining. The phantom is then cast-out of polyvinyl alcohol (PVA), a hydrogel, whose mechanical properties are set by subjecting the phantom to freeze and thaw cycles. Subsequently, blood flow is emulated at a constant volumetric rate at the atrial pressure observed in a healthy adult human heart at rest. The annulus motion is implemented by suturing the outside of the phantom to a one-degree-of-freedom cam-follower mechanism reproducing valve motion. Such test beds could play a significant role in future development of medical devices.
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Affiliation(s)
- Toufic Azar
- Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Stewart McLennan
- Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Michael Walsh
- Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick V94T9PX, Ireland
| | - Jorge Angeles
- Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Jozsef Kövecses
- Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Tabitha Jaramillo
- Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Rosaire Mongrain
- Department of Mechanical Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Renzo Cecere
- McGill University Health Centre, McGill University, Royal Victoria Hospital, Montreal, QC H3A 2A7, Canada
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12
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Rizvi A, Marcus RP, Guo Y, Carter R, Mark IT, Foley TA, Weber NM, Sheedy EN, Leng S, Williamson EE. Dynamic computed tomographic assessment of the mitral annulus in patients with and without mitral prolapse. J Cardiovasc Comput Tomogr 2020; 14:502-509. [PMID: 32253123 DOI: 10.1016/j.jcct.2020.02.005] [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: 11/04/2019] [Revised: 02/07/2020] [Accepted: 02/21/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To obtain 3D CT measurements of mitral annulus throughout cardiac cycle using prototype mitral modeling software, assess interobserver agreement, and compare among patients with mitral prolapse (MP) and control group. BACKGROUND Pre-procedural imaging is critical for planning of transcatheter mitral valve (MV) replacement. However, there is limited data regarding reliable CT-based measurements to accurately characterize the dynamic geometry of the mitral annulus in patients with MV disease. METHODS Patients with MP and control subjects without any MV disease who underwent ECG-gated cardiac CT were retrospectively identified. Multiphasic CT data was loaded into a prototype mitral modeling software. Multiple anatomical parameters in 3D space were recorded throughout the cardiac cycle (0-95%): annular circumference, planar-surface-area (PSA), anterior-posterior (A-P) distance, and anterolateral-posteromedial (AL-PM) distance. Comparisons were made among the two groups, with p < 0.05 considered statistically significant. Interobserver agreement was assessed on ten patients using intraclass correlation coefficient (ICC) among 4 experienced readers. RESULTS A total of 100 subjects were included: 50 with MP and 50 control. Annular dimensions were significantly higher in the MP group than control group, with circumference (144 ± 11 vs. 117±8 mm), PSA (1533 ± 247 vs. 1005 ± 142 mm2), A-P distance (38 ± 4 vs. 32±2 mm), and AL-PM distance (47 ± 4 vs. 39±3 mm) (all p < 0.001). Substantial size changes were observed throughout the cardiac cycle, but with maximal and minimal sizes at different cardiac phases for the two groups. The interobserver agreement was excellent (ICC≥0.75) for annular circumference, PSA, A-P- and AL-PM distance. CONCLUSION A significant variation in the mitral annular measures between different cardiac phases and two groups was observed with excellent interobserver agreement.
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Affiliation(s)
- Asim Rizvi
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA; Department of Medicine, The University of Texas Medical Branch at Galveston, 301 University Blvd, Galveston, TX, 77555, USA.
| | - Roy P Marcus
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Yugene Guo
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Rickey Carter
- Department of Health Sciences Research, 4500 San Pablo Rd S, Mayo Clinic, Jacksonville, FL, 32224, USA.
| | - Ian T Mark
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Thomas A Foley
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Nikkole M Weber
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Emily N Sheedy
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Shuai Leng
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Eric E Williamson
- Department of Radiology, 200 First Street SW, Mayo Clinic, Rochester, MN, 55905, USA.
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Bruno VD. Commentary: Another step in the journey toward the "perfect" mitral valve repair. J Thorac Cardiovasc Surg 2019; 159:1777-1778. [PMID: 31256967 DOI: 10.1016/j.jtcvs.2019.05.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 05/22/2019] [Indexed: 10/26/2022]
Affiliation(s)
- Vito Domenico Bruno
- Department of Translational Health Science, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
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14
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Lansac E, Lim HS, Shomura Y, Lim KH, Rice NT, Di Centa I, Youssefi P, Goetz W, Duran CMG. Aortic valve opening and closure: the clover dynamics. Ann Cardiothorac Surg 2019; 8:351-361. [PMID: 31240179 DOI: 10.21037/acs.2019.05.03] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Systolic aortic root expansion is reported to facilitate valve opening, but the precise dynamics remain unknown. A sonometric study with a high data sampling rate (200 to 800 Hz) was conducted in an acute ovine model to better understand the timing, mechanisms, and shape of aortic valve opening and closure. Methods Eighteen piezoelectric crystals were implanted in 8 sheep at each annular base, commissures, sinus of Valsalva, sinotubular junction, nodulus of Arantius, and ascending aorta (AA). Geometric changes were time related to pressures and flows. Results The aortic root was hemodynamically divided into left ventricular (LV) and aortic compartments situated, respectively, below and above the leaflets. During isovolumetric contraction (IVC), aortic root expansion started in the LV compartment, most likely due to volume redistribution in the LV outflow tract below the leaflets. This expansion initiated leaflet separation prior to ejection (2.1%±0.5% of total opening area). Aortic compartment expansion was delayed toward the end of IVC, likely related to volume redistribution above the leaflets due to accelerating aortic backflow toward the aortic valve and coronary flow reduction due to myocardial contraction. Maximum valve opening during the first third of ejection acquired a truncated cone shape [leaflet free edge area smaller than annular base area (-41.5%±5.5%)]. The distal orifice became clover shaped because the leaflet free edge area is larger than the commissural area by 16.3%±2.0%. Conclusions Aortic valve opening is initiated prior to ejection related to delicate balance between LV, aortic root, and coronary dynamics. It is clover shaped at maximum opening in systole. A better understanding of these mechanisms should stimulate more physiological surgical approaches of valve repair and replacement.
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Affiliation(s)
- Emmanuel Lansac
- Department of Cardiovascular Surgery, Institut Mutualiste Montsouris, Paris, France
| | - Hou-Sen Lim
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
| | - Yu Shomura
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
| | - Khee Hiang Lim
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
| | - Nolan T Rice
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
| | - Isabelle Di Centa
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
| | - Pouya Youssefi
- Department of Cardiovascular Surgery, Institut Mutualiste Montsouris, Paris, France.,Hospital Foch, Suresnes, France
| | - Wolfgang Goetz
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
| | - Carlos M G Duran
- The International Heart Institute of Montana Foundation at St. Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Montana, USA
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15
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Sonomicrometry-derived 3-dimensional geometry of the human tricuspid annulus. J Thorac Cardiovasc Surg 2019; 157:1452-1461.e1. [DOI: 10.1016/j.jtcvs.2018.08.110] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/23/2018] [Accepted: 08/23/2018] [Indexed: 12/17/2022]
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16
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Kormányos Á, Kalapos A, Domsik P, Lengyel C, Forster T, Nemes A. Normal values of left ventricular rotational parameters in healthy adults-Insights from the three-dimensional speckle tracking echocardiographic MAGYAR-Healthy Study. Echocardiography 2019; 36:714-721. [PMID: 30801756 DOI: 10.1111/echo.14285] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 10/19/2018] [Accepted: 01/24/2019] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION Left ventricular (LV) rotation and twist are essential parts of LV function. Three-dimensional speckle tracking echocardiography (3DSTE) is a relatively new method and is useful for the quantification of LV wall deformation and rotational parameters. The aim of the present study was to examine LV rotation and twist differences between different age-groups and genders in a healthy population. METHODS The present study is comprised of 297 healthy adults; 120 adults have been excluded due to inferior image quality. The population was further divided into 4 subgroups based on age decades. RESULTS Only the LV twist of all patients (13.5 ± 3.7 degree vs 15.6 ± 4.9 degree, P = 0.02) and the LV twist of females (13.0 ± 3.6 degree vs 15.5 ± 5.6 degree, P = 0.03) differed significantly between the age-group of 18-29 years and 50+ years. LV basal and apical rotation were not significantly different between the age-groups; however, they tendentiously increased with aging. No significant differences could be demonstrated regarding LV rotational and twist parameters between genders in any group. A phenomenon called LV rigid body rotation (LV-RBR)-where the base and apex of the LV rotate in the same direction-was present in 10 cases. CONCLUSIONS Three-dimensional speckle tracking echocardiography seems to be a reasonably viable tool for the quantification of LV rotation and twist. Both LV basal and apical rotation and LV twist increase with aging, regardless of gender. LV-RBR is also present in the normal population.
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Affiliation(s)
- Árpád Kormányos
- 2nd Department of Medicine and Cardiology Centre, Medical Faculty, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | - Anita Kalapos
- 2nd Department of Medicine and Cardiology Centre, Medical Faculty, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | - Péter Domsik
- 2nd Department of Medicine and Cardiology Centre, Medical Faculty, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | - Csaba Lengyel
- 1st Department of Medicine, Medical Faculty, Albert Szent-Györgyi Clinical Centre, University of Szeged, Szeged, Hungary
| | - Tamás Forster
- 2nd Department of Medicine and Cardiology Centre, Medical Faculty, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
| | - Attila Nemes
- 2nd Department of Medicine and Cardiology Centre, Medical Faculty, Albert Szent-Györgyi Clinical Center, University of Szeged, Szeged, Hungary
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Regional Myocardial Strain and Function: From Novel Techniques to Clinical Applications. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/978-1-4939-8841-9_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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18
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Rego BV, Khalighi AH, Drach A, Lai EK, Pouch AM, Gorman RC, Gorman JH, Sacks MS. A noninvasive method for the determination of in vivo mitral valve leaflet strains. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3142. [PMID: 30133180 DOI: 10.1002/cnm.3142] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/21/2018] [Accepted: 08/07/2018] [Indexed: 06/08/2023]
Abstract
Assessment of mitral valve (MV) function is important in many diagnostic, prognostic, and surgical planning applications for treatment of MV disease. Yet, to date, there are no accepted noninvasive methods for determination of MV leaflet deformation, which is a critical metric of MV function. In this study, we present a novel, completely noninvasive computational method to estimate MV leaflet in-plane strains from clinical-quality real-time three-dimensional echocardiography (rt-3DE) images. The images were first segmented to produce meshed medial-surface leaflet geometries of the open and closed states. To establish material point correspondence between the two states, an image-based morphing pipeline was implemented within a finite element (FE) modeling framework in which MV closure was simulated by pressurizing the open-state geometry, and local corrective loads were applied to enforce the actual MV closed shape. This resulted in a complete map of local systolic leaflet membrane strains, obtained from the final FE mesh configuration. To validate the method, we utilized an extant in vitro database of fiducially labeled MVs, imaged in conditions mimicking both the healthy and diseased states. Our method estimated local anisotropic in vivo strains with less than 10% error and proved to be robust to changes in boundary conditions similar to those observed in ischemic MV disease. Next, we applied our methodology to ovine MVs imaged in vivo with rt-3DE and compared our results to previously published findings of in vivo MV strains in the same type of animal as measured using surgically sutured fiducial marker arrays. In regions encompassed by fiducial markers, we found no significant differences in circumferential(P = 0.240) or radial (P = 0.808) strain estimates between the marker-based measurements and our novel noninvasive method. This method can thus be used for model validation as well as for studies of MV disease and repair.
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Affiliation(s)
- Bruno V Rego
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Amir H Khalighi
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Andrew Drach
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Eric K Lai
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael S Sacks
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
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Tricuspid valvular dynamics and 3-dimensional geometry in awake and anesthetized sheep. J Thorac Cardiovasc Surg 2018; 156:1503-1511. [DOI: 10.1016/j.jtcvs.2018.04.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/04/2018] [Accepted: 04/13/2018] [Indexed: 11/17/2022]
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20
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Torres WM, Jacobs J, Doviak H, Barlow SC, Zile MR, Shazly T, Spinale FG. Regional and temporal changes in left ventricular strain and stiffness in a porcine model of myocardial infarction. Am J Physiol Heart Circ Physiol 2018; 315:H958-H967. [PMID: 30004234 DOI: 10.1152/ajpheart.00279.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The aim of the present study was to serially track how myocardial infarction (MI) impacts regional myocardial strain and mechanical properties of the left ventricle (LV) in a large animal model. Post-MI remodeling has distinct regional effects throughout the LV myocardium. Regional quantification of LV biomechanical behavior could help explain changes in global function and thus advance clinical assessment of post-MI remodeling. The present study is based on a porcine MI model to characterize LV biomechanics over 28 days post-MI via speckle-tracking echocardiography (STE). Regional myocardial strain and strain rate were recorded in the circumferential, radial, and longitudinal directions at baseline and at 3, 14, and 28 days post-MI. Regional myocardial wall stress was calculated using standard echocardiographic metrics of geometry and Doppler-derived hemodynamic measurements. Regional diastolic myocardial stiffness was calculated from the resultant stress-strain relations. Peak strain and phasic strain rates were nonuniformly reduced throughout the myocardium post-MI, whereas time to peak strain was increased to a similar degree in the MI region and border zone by 28 days post-MI. Elevations in diastolic myocardial stiffness in the MI region plateaued at 14 days post-MI, after which a significant reduction in MI regional stiffness in the longitudinal direction occurred between 14 and 28 days post-MI. Post-MI biomechanical changes in the LV myocardium were initially limited to the MI region but nonuniformly extended into the neighboring border zone and remote myocardium over 28 days post-MI. STE enabled quantification of regional and temporal differences in myocardial strain and diastolic stiffness, underscoring the potential of this technique for clinical assessment of post-MI remodeling. NEW & NOTEWORTHY For the first time, speckle-tracking echocardiography was used to serially track regional biomechanical behavior and mechanical properties postmyocardial infarction (post-MI). We found that changes initially confined to the MI region extended throughout the myocardium in a nonuniform fashion over 28 days post-MI. Speckle-tracking echocardiography-based evaluation of regional changes in left ventricular biomechanics could advance both clinical assessment of left ventricular remodeling and therapeutic strategies that target aberrant biomechanical behavior post-MI.
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Affiliation(s)
- William M Torres
- College of Engineering and Computing, University of South Carolina , Columbia, South Carolina.,Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the William Jennings Bryan Dorn Veteran Affairs Medical Center , Columbia, South Carolina
| | - Julia Jacobs
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the William Jennings Bryan Dorn Veteran Affairs Medical Center , Columbia, South Carolina
| | - Heather Doviak
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the William Jennings Bryan Dorn Veteran Affairs Medical Center , Columbia, South Carolina
| | - Shayne C Barlow
- Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the William Jennings Bryan Dorn Veteran Affairs Medical Center , Columbia, South Carolina
| | - Michael R Zile
- Medical University of South Carolina and Ralph H. Johnson Department of Veterans Affairs Medical Center , Charleston, South Carolina
| | - Tarek Shazly
- College of Engineering and Computing, University of South Carolina , Columbia, South Carolina
| | - Francis G Spinale
- College of Engineering and Computing, University of South Carolina , Columbia, South Carolina.,Cardiovascular Translational Research Center, University of South Carolina School of Medicine and the William Jennings Bryan Dorn Veteran Affairs Medical Center , Columbia, South Carolina
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Tjørnild MJ, Skov SN, Røpcke DM, Ilkjær C, Rasmussen J, Couetil JP, Nielsen SL. Mitral annuloplasty ring with selective flexibility for septal–lateral contraction and remodelling properties†. Interact Cardiovasc Thorac Surg 2018; 28:65-70. [DOI: 10.1093/icvts/ivy194] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/18/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marcell J Tjørnild
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Søren N Skov
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Diana M Røpcke
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Christine Ilkjær
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Jonas Rasmussen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Jean-Paul Couetil
- Department of Thoracic and Cardiovascular Surgery, University Hospital Group Henri Mondor, APHP, Paris-Est Créteil University, Créteil, France
| | - Sten L Nielsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
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22
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Tjørnild MJ, Skov SN, Poulsen KB, Sharghbin M, Benhassen LL, Carlson Hanse L, Waziri F, Røpcke DM, Nielsen SL, Hasenkam JM. Mitral valve posterior leaflet reconstruction using extracellular matrix: an acute porcine study†. Eur J Cardiothorac Surg 2018; 54:832-840. [DOI: 10.1093/ejcts/ezy152] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/14/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Marcell J Tjørnild
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Søren N Skov
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Karen B Poulsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mona Sharghbin
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Leila L Benhassen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Lisa Carlson Hanse
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Farhad Waziri
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Diana M Røpcke
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Sten L Nielsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - J Michael Hasenkam
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
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Villard PF, Hammer PE, Perrin DP, del Nido PJ, Howe RD. Fast image-based mitral valve simulation from individualized geometry. Int J Med Robot 2018; 14. [DOI: 10.1002/rcs.1880] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Pierre-Frederic Villard
- LORIA; University of Lorraine; Inria Nancy France
- Harvard School of Engineering and Applied Sciences; Cambridge MA, USA
| | - Peter E. Hammer
- Harvard School of Engineering and Applied Sciences; Cambridge MA, USA
- Department of Cardiac Surgery; Boston Children's Hospital; Boston MA, USA
| | - Douglas P. Perrin
- Harvard School of Engineering and Applied Sciences; Cambridge MA, USA
- Department of Cardiac Surgery; Boston Children's Hospital; Boston MA, USA
| | - Pedro J. del Nido
- Department of Cardiac Surgery; Boston Children's Hospital; Boston MA, USA
| | - Robert D. Howe
- Harvard School of Engineering and Applied Sciences; Cambridge MA, USA
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Amini Khoiy K, Biswas D, Decker TN, Asgarian KT, Loth F, Amini R. Surface Strains of Porcine Tricuspid Valve Septal Leaflets Measured in Ex Vivo Beating Hearts. J Biomech Eng 2017; 138:2551875. [PMID: 27598222 DOI: 10.1115/1.4034621] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Indexed: 11/08/2022]
Abstract
Quantification of the tricuspid valve (TV) leaflets mechanical strain is important in order to understand valve pathophysiology and to develop effective treatment strategies. Many of the traditional methods used to dynamically open and close the cardiac valves in vitro via flow simulators require valve dissection. Recent studies, however, have shown that restriction of the atrioventricular valve annuli could significantly change their in vivo deformation. For the first time, the porcine valve leaflets deformation was measured in a passive ex vivo beating heart without isolating and remounting the valve annuli. In particular, the right ventricular apexes of porcine hearts (n = 8) were connected to a pulse-duplicator pump that maintained a pulsatile flow from and to a reservoir connected to the right atrium and the pulmonary arteries. This pump provided a right ventricular pressure (RVP) waveform that closely matched physiological values, leading to opening and closure of the tricuspid and pulmonary valves (PVs). At the midsection of the valve leaflets, the peak areal strain was 9.8 ± 2.0% (mean±standard error). The peak strain was 5.6 ± 1.1% and 4.3 ± 1.0% in the circumferential and radial directions, respectively. Although the right ventricle was beating passively, the leaflet peak areal strains closely matched the values measured in other atrioventricular valves (i.e., the mitral valve (MV)) in vivo. This technique can be used to measure leaflet strains with and without the presence of valve lesions to help develop/evaluate treatment strategies to restore normal valve deformation.
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Affiliation(s)
- Keyvan Amini Khoiy
- Department of Biomedical Engineering, The University of Akron, Akron, OH 44325 e-mail:
| | - Dipankar Biswas
- Department of Mechanical Engineering, The University of Akron, Akron, OH 44325 e-mail:
| | - Thomas N Decker
- Department of Biomedical Engineering, The University of Akron, Akron, OH 44325 e-mail:
| | - Kourosh T Asgarian
- Cardiothoracic Surgery, St. Joseph's Regional Medical Center, Paterson, NJ 07503 e-mail:
| | - Francis Loth
- Department of Mechanical Engineering, The University of Akron, Akron, OH 44325 e-mail:
| | - Rouzbeh Amini
- Mem. ASME Department of Biomedical Engineering, The University of Akron, 260 S Forge Street, Olson Research Center Room 301F, Akron, OH 44325 e-mail:
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25
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Watanabe N, Maltais S, Nishino S, O'Donoghue TA, Hung J. Functional Mitral Regurgitation: Imaging Insights, Clinical Outcomes and Surgical Principles. Prog Cardiovasc Dis 2017; 60:351-360. [PMID: 29162536 DOI: 10.1016/j.pcad.2017.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 11/15/2017] [Indexed: 01/14/2023]
Abstract
Functional mitral regurgitation (MR; FMR) is the most common type of MR and its development is associated with increased morbidity and mortality. Leaflet tethering with apical shift of the papillary muscle due to adverse left ventricular remodeling and loss of normal leaflet coaptation is the principal mechanism of FMR. Echocardiography plays a central role in the assessment of the FMR. The development of 3D echocardiography has allowed for assessment of the geometric changes of mitral valve morphology and spatial relationship with the left ventricle that accompanies FMR. 2D/3D echocardiographic findings, clinical outcomes of FMR are reviewed and role of surgical intervention is discussed.
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Affiliation(s)
- Nozomi Watanabe
- Miyazaki Medical Association Hospital Cardiovascular Center, Miyazaki, Japan.
| | - Simon Maltais
- Mayo Clinic, Cardiovascular Surgery, Rochester, MN, USA
| | - Shun Nishino
- Miyazaki Medical Association Hospital Cardiovascular Center, Miyazaki, Japan
| | | | - Judy Hung
- Massachusetts General Hospital, Cardiology, Boston, MA, USA
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26
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Lee CH, Zhang W, Feaver K, Gorman RC, Gorman JH, Sacks MS. On the in vivo function of the mitral heart valve leaflet: insights into tissue-interstitial cell biomechanical coupling. Biomech Model Mechanobiol 2017; 16:1613-1632. [PMID: 28429161 DOI: 10.1007/s10237-017-0908-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 04/07/2017] [Indexed: 10/19/2022]
Abstract
There continues to be a critical need for developing data-informed computational modeling techniques that enable systematic evaluations of mitral valve (MV) function. This is important for a better understanding of MV organ-level biomechanical performance, in vivo functional tissue stresses, and the biosynthetic responses of MV interstitial cells (MVICs) in the normal, pathophysiological, and surgically repaired states. In the present study, we utilized extant ovine MV population-averaged 3D fiducial marker data to quantify the MV anterior leaflet (MVAL) deformations in various kinematic states. This approach allowed us to make the critical connection between the in vivo functional and the in vitro experimental configurations. Moreover, we incorporated the in vivo MVAL deformations and pre-strains into an enhanced inverse finite element modeling framework (Path 1) to estimate the resulting in vivo tissue prestresses [Formula: see text] and the in vivo peak functional tissue stresses [Formula: see text]. These in vivo stress estimates were then cross-verified with the results obtained from an alternative forward modeling method (Path 2), by taking account of the changes in the in vitro and in vivo reference configurations. Moreover, by integrating the tissue-level kinematic results into a downscale MVIC microenvironment FE model, we were able to estimate, for the first time, the in vivo layer-specific MVIC deformations and deformation rates of the normal and surgically repaired MVALs. From these simulations, we determined that the placement of annuloplasty ring greatly reduces the peak MVIC deformation levels in a layer-specific manner. This suggests that the associated reductions in MVIC deformation may down-regulate MV extracellular matrix maintenance, ultimately leading to reduction in tissue mechanical integrity. These simulations provide valuable insight into MV cellular mechanobiology in response to organ- and tissue-level alternations induced by MV disease or surgical repair. They will also assist in the future development of computer simulation tools for guiding MV surgery procedure with enhanced durability and improved long-term surgical outcomes.
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Affiliation(s)
- Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall, Rm. 219C, Norman, OK, 73019, USA.,Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA
| | - Will Zhang
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA
| | - Kristen Feaver
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Michael S Sacks
- Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th St, POB 5.236, 1 University Station, C0200, Austin, TX, 78712, USA. .,W. A. Moncrief, Jr. Simulation-Based Engineering Science Chair I, Department of Biomedical Engineering, Institute for Computational Engineering and Sciences, The University of Texas at Austin, 201 East 24th Street, ACES 5.438, 1 University Station, C0200, Austin, TX, 78712-0027, USA.
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El Sebaie MH, Abdelatti M, Zarea A, Farag A, Hashem A, Fadel A. Assessment of mitral valve geometric deformity in patients with ischemic heart disease using three-dimensional echocardiography. Egypt Heart J 2017; 69:13-20. [PMID: 29622950 PMCID: PMC5839364 DOI: 10.1016/j.ehj.2016.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/14/2016] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND A full understanding of the geometry of the nonplanar saddle-shaped mitral annulus can provide valuable information regarding the pathophysiology of mitral regurgitation (MR). AIM OF THE WORK To investigate mitral annular geometric deformities using three-dimensional echocardiography among patients with ischemic coronary illness with and without mitral regurgitation. METHODS Three-dimensional transesophageal echocardiographic data were acquired intraoperatively from patients with ischemic heart disease with or without associated mitral regurgitation who experienced coronary artery bypass grafting and normal control subjects. The mitral annulus was analyzed for differences in geometry using QLAB software. RESULTS Left ventricular ejection fraction was reduced in patients with ischemic heart disease and MR (n = 21; Group 1) and without MR (n = 7; Group 2) compared with that in normal subjects (n = 14; Group 3) (43.4% ± 11.8% and 35.9% ± 13.6% vs. 52.6% ± 9.3%, respectively; p = 0.015). Mitral annular height and mitral annular saddle-shaped nonplanarity were significantly lower in Group 1 compared to Group 2 and Group 3 (6.00 ± 1.07 mm, 7.96 ± 0.93 mm and 8.31 ± 1.12 mm; p < 0.0001) and (0.19 ± 0.04, 0.26 ± 0.04 and 0.26 ± 0.03; p < 0.0001) respectively while mitral annular ellipsicity and Mitral valve tenting volume were significantly higher in the same group (1) (114.82% ± 22.47%, 100.21% ± 9.87% and 97.29% ± 14.37%; p = 0.0421) and (2.73 ± 1.11, 2.20 ± 1.39 and 0.87 ± 0.67) respectively. Vena contracta diameter was inversely correlated with the mitral annular height (r = -0.82; p < 0.0001) and saddle-shaped nonplanarity of the annulus (r = -0.68; p < 0.0001). CONCLUSION Among patients with ischemic heart disease, there are significant increases in mitral valve tenting volume and height, and those with mitral regurgitation exhibited a reduced mitral annular height, a shallower saddle shape annulus and losses of ellipsicity of the annulus.
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Affiliation(s)
- Maha H. El Sebaie
- Cardiology Department, Zagazig University, Egypt
- King Abdulla Medical City, Saudi Arabia
| | - M.N. Abdelatti
- Anesthesia Department, King Abdulla Medical City, Saudi Arabia
| | - A.A. Zarea
- Anesthesia Department, King Abdulla Medical City, Saudi Arabia
| | - A.M. Farag
- Anesthesia Department, King Abdulla Medical City, Saudi Arabia
| | - A.A. Hashem
- Anesthesia Department, King Abdulla Medical City, Saudi Arabia
| | - A.M. Fadel
- Anesthesia Department, King Abdulla Medical City, Saudi Arabia
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Skov SN, Røpcke DM, Tjørnild MJ, Ilkjær C, Rasmussen J, Nygaard H, Jensen MO, Nielsen SL. Semi-rigid mitral annuloplasty rings improve myocardial stress adaptation compared to rigid rings: insights from in vitro and in vivo experimental evaluation†. Eur J Cardiothorac Surg 2017; 51:836-843. [DOI: 10.1093/ejcts/ezw421] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/30/2016] [Indexed: 11/14/2022] Open
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Rausch MK, Zöllner AM, Genet M, Baillargeon B, Bothe W, Kuhl E. A virtual sizing tool for mitral valve annuloplasty. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:10.1002/cnm.2788. [PMID: 27028496 PMCID: PMC5289896 DOI: 10.1002/cnm.2788] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/16/2016] [Accepted: 03/19/2016] [Indexed: 05/08/2023]
Abstract
Functional mitral regurgitation, a backward leakage of the mitral valve, is a result of left ventricular growth and mitral annular dilatation. Its gold standard treatment is mitral annuloplasty, the surgical reduction in mitral annular area through the implantation of annuloplasty rings. Recurrent regurgitation rates may, however, be as high as 30% and more. While the degree of annular downsizing has been linked to improved long-term outcomes, too aggressive downsizing increases the risk of ring dehiscences and significantly impairs repair durability. Here, we prototype a virtual sizing tool to quantify changes in annular dimensions, surgically induced tissue strains, mitral annular stretches, and suture forces in response to mitral annuloplasty. We create a computational model of dilated cardiomyopathy onto which we virtually implant annuloplasty rings of different sizes. Our simulations confirm the common intuition that smaller rings are more invasive to the surrounding tissue, induce higher strains, and require larger suture forces than larger rings: The total suture force was 2.2 N for a 24-mm ring, 1.9 N for a 28-mm ring, and 0.8 N for a 32-mm ring. Our model predicts the highest risk of dehiscence in the septal and postero-lateral annulus where suture forces are maximal. These regions co-localize with regional peaks in myocardial strain and annular stretch. Our study illustrates the potential of realistic predictive simulations in cardiac surgery to identify areas at risk for dehiscence, guide the selection of ring size and shape, rationalize the design of smart annuloplasty rings and, ultimately, improve long-term outcomes after surgical mitral annuloplasty. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Manuel K. Rausch
- Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Alexander M. Zöllner
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Martin Genet
- Laboratoire de Mécanique des Solides CNRS-UMR 7649, Ecole Polytechnique, 91128 Palaiseau, France
| | | | - Wolfgang Bothe
- University Heart Center Freiburg, 79106 Freiburg, Germany
| | - E. Kuhl
- Departments of Mechanical Engineering, Bioengineering and Cardiothoracic Surgery, Stanford University, Stanford, CA 94305, USA
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30
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Mitral annuloplasty ring dehiscence: Optimal force distribution with flexible rings. J Thorac Cardiovasc Surg 2016; 152:1639. [DOI: 10.1016/j.jtcvs.2016.07.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 07/25/2016] [Indexed: 11/19/2022]
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31
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Ayoub S, Ferrari G, Gorman RC, Gorman JH, Schoen FJ, Sacks MS. Heart Valve Biomechanics and Underlying Mechanobiology. Compr Physiol 2016; 6:1743-1780. [PMID: 27783858 PMCID: PMC5537387 DOI: 10.1002/cphy.c150048] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Heart valves control unidirectional blood flow within the heart during the cardiac cycle. They have a remarkable ability to withstand the demanding mechanical environment of the heart, achieving lifetime durability by processes involving the ongoing remodeling of the extracellular matrix. The focus of this review is on heart valve functional physiology, with insights into the link between disease-induced alterations in valve geometry, tissue stress, and the subsequent cell mechanobiological responses and tissue remodeling. We begin with an overview of the fundamentals of heart valve physiology and the characteristics and functions of valve interstitial cells (VICs). We then provide an overview of current experimental and computational approaches that connect VIC mechanobiological response to organ- and tissue-level deformations and improve our understanding of the underlying functional physiology of heart valves. We conclude with a summary of future trends and offer an outlook for the future of heart valve mechanobiology, specifically, multiscale modeling approaches, and the potential directions and possible challenges of research development. © 2016 American Physiological Society. Compr Physiol 6:1743-1780, 2016.
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Affiliation(s)
- Salma Ayoub
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, USA
| | - Giovanni Ferrari
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, USA
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, USA
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, USA
| | - Frederick J. Schoen
- Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Michael S. Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, USA
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Soares JS, Feaver KR, Zhang W, Kamensky D, Aggarwal A, Sacks MS. Biomechanical Behavior of Bioprosthetic Heart Valve Heterograft Tissues: Characterization, Simulation, and Performance. Cardiovasc Eng Technol 2016; 7:309-351. [PMID: 27507280 DOI: 10.1007/s13239-016-0276-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 07/13/2016] [Indexed: 12/11/2022]
Abstract
The use of replacement heart valves continues to grow due to the increased prevalence of valvular heart disease resulting from an ageing population. Since bioprosthetic heart valves (BHVs) continue to be the preferred replacement valve, there continues to be a strong need to develop better and more reliable BHVs through and improved the general understanding of BHV failure mechanisms. The major technological hurdle for the lifespan of the BHV implant continues to be the durability of the constituent leaflet biomaterials, which if improved can lead to substantial clinical impact. In order to develop improved solutions for BHV biomaterials, it is critical to have a better understanding of the inherent biomechanical behaviors of the leaflet biomaterials, including chemical treatment technologies, the impact of repetitive mechanical loading, and the inherent failure modes. This review seeks to provide a comprehensive overview of these issues, with a focus on developing insight on the mechanisms of BHV function and failure. Additionally, this review provides a detailed summary of the computational biomechanical simulations that have been used to inform and develop a higher level of understanding of BHV tissues and their failure modes. Collectively, this information should serve as a tool not only to infer reliable and dependable prosthesis function, but also to instigate and facilitate the design of future bioprosthetic valves and clinically impact cardiology.
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Affiliation(s)
- Joao S Soares
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Stop C0200, Austin, TX, 78712-1129, USA
| | - Kristen R Feaver
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Stop C0200, Austin, TX, 78712-1129, USA
| | - Will Zhang
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Stop C0200, Austin, TX, 78712-1129, USA
| | - David Kamensky
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Stop C0200, Austin, TX, 78712-1129, USA
| | - Ankush Aggarwal
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Stop C0200, Austin, TX, 78712-1129, USA
- College of Engineering, Swansea University, Bay Campus, Fabian Way, Swansea, SA1 8EN, UK
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Stop C0200, Austin, TX, 78712-1129, USA.
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Sonomicrometry-Based Analysis of Post-Myocardial Infarction Regional Mechanics. Ann Biomed Eng 2016; 44:3539-3552. [PMID: 27411709 DOI: 10.1007/s10439-016-1694-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/05/2016] [Indexed: 02/04/2023]
Abstract
Following myocardial infarction (MI), detrimental changes to the geometry, composition, and mechanical properties of the left ventricle (LV) are initiated in a process generally termed adverse post-MI remodeling. Cumulatively, these changes lead to a loss of LV function and are deterministic factors in the progression to heart failure. Proposed therapeutic strategies to target aberrant LV mechanics post-MI have shown potential to stabilize LV functional indices throughout the remodeling process. The in vivo quantification of LV mechanics, particularly within the MI region, is therefore essential to the continued development and evaluation of strategies to interrupt the post-MI remodeling process. The present study utilizes a porcine MI model and in vivo sonomicrometry to characterize MI region stiffness at 14 days post-MI. Obtained results demonstrate a significant dependence of mechanical properties on location and direction within the MI region, as well as cardiac phase. While approaches for comprehensive characterization of LV mechanics post-MI still need to be improved and standardized, our findings provide insight into the issues and complexities that must be considered within the MI region itself.
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Goetz WA, Lansac E, Lim HS, Stevens SA, Weber PA, Duran CMG. Kinking of the Atrioventricular Plane during the Cardiac Cycle. Asian Cardiovasc Thorac Ann 2016; 14:394-8. [PMID: 17005886 DOI: 10.1177/021849230601400509] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Systolic descent of the atrioventricular plane toward the relatively stationary left ventricular apex is well described. As the atrioventricular plane includes two separate valvular units, systolic atrioventricular plane displacement should not be homogenous. In 6 sheep, sonomicrometric crystals were implanted at the base of the right coronary sinus, anterolateral and posteromedial fibrous trigones, posterior mitral annulus, left ventricular apex, and the tips of the anterior and posterior mitral leaflets. The aortomitral angle was calculated and related to simultaneous left ventricular and aortic pressures and mitral valve movement. The aortomitral angle was largest at end diastole (150.73° ± 15.48°). During isovolumic contraction, it narrowed rapidly to 144.90° ± 16.64°, followed by a slower narrowing during ejection until it reached its smallest angle at end systole (139.66° ± 16.78°). During isovolumic relaxation, the aortomitral angle increased to 143.66° ± 16.02° at the beginning of diastole. During the first third of diastole, it narrowed again to 141° ± 16.24° before re-expanding to maximum at end diastole. During systole, the atrioventricular plane descended non-homogeneously toward the apex, with kinking at the hinge between the aortic and mitral annulus plane. This deformation of the atrioventricular plane has relevance in valve surgery.
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Affiliation(s)
- Wolfgang A Goetz
- The International Heart Institute of Montana, 554 West Broadway, Missoula, MT 59802, USA.
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Menciotti G, Borgarelli M, Aherne M, Häggström J, Ljungvall I, Lahmers S, Abbott J. Assessment of mitral valve morphology using three-dimensional echocardiography. Feasibility and reference values. J Vet Cardiol 2016; 18:156-67. [DOI: 10.1016/j.jvc.2015.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 11/23/2015] [Accepted: 11/23/2015] [Indexed: 01/04/2023]
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36
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Malinowski M, Wilton P, Khaghani A, Brown M, Langholz D, Hooker V, Eberhart L, Hooker RL, Timek TA. The effect of acute mechanical left ventricular unloading on ovine tricuspid annular size and geometry. Interact Cardiovasc Thorac Surg 2016; 23:391-6. [PMID: 27209530 DOI: 10.1093/icvts/ivw138] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 04/12/2016] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Left ventricular assist device (LVAD) implantation may alter right ventricular shape and function and lead to tricuspid regurgitation. This in turn has been reported to be a determinant of right ventricular (RV) failure after LVAD implantation, but the effect of mechanical left ventricular (LV) unloading on the tricuspid annulus is unknown. The aim of the study was to provide insight into the effect of LVAD support on tricuspid annular geometry and dynamics that may help to optimize LV unloading with the least deleterious effect on the right-sided geometry. METHODS In seven open-chest anaesthetized sheep, nine sonomicrometry crystals were implanted on the right ventricle. Additional nine crystals were implanted around the tricuspid annulus, with one crystal at each commissure defining three separate annular regions: anterior, posterior and septal. Left ventricular unloading was achieved by connecting a cannula in the left atrium and the aorta to a continuous-flow pump. The pump was used for 15 min at a full flow of 3.8 ± 0.3 l/min. Epicardial echocardiography was used to assess the degree of tricuspid insufficiency. Haemodynamic, echocardiographic and sonomicrometry data were collected before and during full unloading. Tricuspid annular area, and the regional and total perimeter were calculated from crystal coordinates, while 3D annular geometry was expressed as the orthogonal distance of each annular crystal to the least squares plane of all annular crystals. RESULTS There was no significant tricuspid regurgitation observed either before or during LV unloading. Right ventricular free wall to septum diameter increased significantly at end-diastole during unloading from 23.6 ± 5.8 to 26.3 ± 6.5 mm (P = 0.009), but the right ventricular volume, tricuspid annular area and total perimeter did not change from baseline. However, the septal part of the annulus significantly decreased its maximal length (38.6 ± 8.1 to 37.9 ± 8.2 mm, P = 0.03). Annular contraction was not altered. The tricuspid annulus had a complex 3D saddle-shaped geometry that was unaffected during experimental conditions. CONCLUSIONS In healthy sheep hearts, left ventricular unloading increased septal-free wall RV diameter and reduced the length of the septal annulus, without altering the motion or geometry of the tricuspid annulus. Acute left ventricular unloading alone in healthy sheep was not sufficient to significantly perturb tricuspid annular dynamics and result in tricuspid insufficiency.
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Affiliation(s)
- Marcin Malinowski
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA Department of Cardiac Surgery, Medical University of Silesia, School of Medicine in Katowice, Katowice, Poland
| | - Penny Wilton
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - Asghar Khaghani
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - Michael Brown
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - David Langholz
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - Victoria Hooker
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - Lenora Eberhart
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - Robert L Hooker
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
| | - Tomasz A Timek
- Meijer Heart and Vascular Institute at Spectrum Health, Grand Rapids, MI, USA
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Comparison of saddle-shape flexibility and elliptical-shape stability between Cosgrove-Edwards and Memo-3D annuloplasty rings using three-dimensional analysis software. Gen Thorac Cardiovasc Surg 2016; 64:325-32. [PMID: 27052546 DOI: 10.1007/s11748-016-0645-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/24/2016] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To compare three-dimensional dynamics between implanted Cosgrove-Edwards and Sorin Memo-3D annuloplasty rings during the cardiac cycle. METHODS We examined 11 Cosgrove-Edwards rings and 20 Sorin Memo-3D rings after mitral plasty using real-time three-dimensional transesophageal echocardiography. We evaluated ring height, ellipticity, and geometry during one cardiac cycle. Four evenly spaced phases each selected during systole and diastole were assessed using REAL VIEW software. RESULTS The height of the Cosgrove-Edwards and Sorin Memo-3D rings was similar (2.3 ± 0.8 vs. 1.9 ± 0.9 mm, p = 0.44). The maximum difference in ring height during one cardiac cycle (change in height) was larger for the Cosgrove-Edwards than the Sorin Memo-3D rings (2.3 ± 0.8 vs. 1.5 ± 0.6 mm, p = 0.014). Ellipticity and the maximum difference in ellipticity during one cardiac cycle (change in ellipticity) were larger for Cosgrove-Edwards than Sorin Memo-3D rings (80.0 ± 9.1 vs. 72.0 ± 4.8 %, p = 0.014, respectively, and 12.0 ± 3.1 vs. 6.0 ± 1.8 %, p < 0.001). CONCLUSIONS Cosgrove-Edwards rings were more flexible, whereas Sorin Memo-3D rings maintained the elliptical shape more effectively.
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Bothe W, Schubert H, Diab M, Faerber G, Bettag C, Jiang X, Fischer MS, Denzler J, Doenst T. Fully automated tracking of cardiac structures using radiopaque markers and high-frequency videofluoroscopy in an in vivo ovine model: from three-dimensional marker coordinates to quantitative analyses. SPRINGERPLUS 2016; 5:220. [PMID: 27026914 PMCID: PMC4771645 DOI: 10.1186/s40064-016-1868-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 02/16/2016] [Indexed: 11/10/2022]
Abstract
PURPOSE Recently, algorithms were developed to track radiopaque markers in the heart fully automated. However, the methodology did not allow to assign the exact anatomical location to each marker. In this case study we describe the steps from the generation of three-dimensional marker coordinates to quantitative data analyses in an in vivo ovine model. METHODS In one adult sheep, twenty silver balls were sutured to the right side of the heart: 10 to the tricuspid annulus, one to the anterior tricuspid leaflet and nine to the epicardial surface of the right ventricle. In addition, 13 cylindrical tantalum markers were implanted into the left ventricle. Data were acquired with a biplanar X-ray acquisition system (Neurostar R, Siemens AG, 500 Hz). Radiopaque marker coordinates were determined fully automated using novel tracking algorithms. RESULTS The anatomical marker locations were identified using a 3-dimensional model of a single frame containing all tracked markers. First, cylindrical markers were manually separated from spherical markers, thus allowing to distinguish right from left heart markers. The fast moving leaflet marker was identified by using video loops constructed of all recorded frames. Rotation of the 3-dimensional model allowed the identification of the precise anatomical position for each marker. Data sets were then analyzed quantitatively using customized software. CONCLUSIONS The method presented in this case study allowed quantitative data analyses of radiopaque cardiac markers that were tracked fully automated with high temporal resolution. However, marker identification still requires substantial manual work. Future improvements including the implication of marker identification algorithms and data analysis software could allow almost real-time quantitative analyses of distinct cardiac structures with high temporal and spatial resolution.
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Affiliation(s)
- Wolfgang Bothe
- Department of Cardiothoracic Surgery, University Hospital Jena, 07747 Jena, Germany ; Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany
| | - Harald Schubert
- Institute of Laboratory Animals Science, Friedrich-Schiller-University, Jena, Germany
| | - Mahmoud Diab
- Department of Cardiothoracic Surgery, University Hospital Jena, 07747 Jena, Germany
| | - Gloria Faerber
- Department of Cardiothoracic Surgery, University Hospital Jena, 07747 Jena, Germany
| | - Christoph Bettag
- Department of Cardiothoracic Surgery, University Hospital Jena, 07747 Jena, Germany
| | - Xiaoyan Jiang
- Computer Vision Group, Friedrich Schiller University, Jena, Germany
| | - Martin S Fischer
- Institute of Systematic Zoology and Evolutionary Biology, Friedrich Schiller University, Jena, Germany
| | - Joachim Denzler
- Computer Vision Group, Friedrich Schiller University, Jena, Germany
| | - Torsten Doenst
- Department of Cardiothoracic Surgery, University Hospital Jena, 07747 Jena, Germany
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Siefert AW, Siskey RL. Bench Models for Assessing the Mechanics of Mitral Valve Repair and Percutaneous Surgery. Cardiovasc Eng Technol 2015; 6:193-207. [PMID: 26577235 DOI: 10.1007/s13239-014-0196-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/19/2014] [Indexed: 01/01/2023]
Abstract
Rapid preclinical evaluations of mitral valve (MV) mechanics are currently best facilitated by bench models of the left ventricle (LV). This review aims to provide a comprehensive assessment of these models to aid interpretation of their resulting data, inform future experimental evaluations, and further the translation of results to procedure and device development. For this review, two types of experimental bench models were evaluated. Rigid LV models were characterized as fluid-mechanical systems capable of testing explanted MVs under static and or pulsatile left heart hemodynamics. Passive LV models were characterized as explanted hearts whose left side is placed in series with a static or pulsatile flow-loop. In both systems, MV function and mechanics can be quantitatively evaluated. Rigid and passive LV models were characterized and evaluated. The materials and methods involved in their construction, function, quantitative capabilities, and disease modeling were described. The advantages and disadvantages of each model are compared to aid the interpretation of their resulting data and inform future experimental evaluations. Repair and percutaneous studies completed in these models were additionally summarized with perspective on future advances discussed. Bench models of the LV provide excellent platforms for quantifying MV repair mechanics and function. While exceptional work has been reported, more research and development is necessary to improve techniques and devices for repair and percutaneous surgery. Continuing efforts in this field will significantly contribute to the further development of procedures and devices, predictions of long-term performance, and patient safety.
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Affiliation(s)
- Andrew W Siefert
- Exponent Failure Analysis Associates, 3440 Market Street Suite 600, Philadelphia, PA, 19104, USA.
| | - Ryan L Siskey
- Exponent Failure Analysis Associates, 3440 Market Street Suite 600, Philadelphia, PA, 19104, USA
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Lee CH, Rabbah JP, Yoganathan AP, Gorman RC, Gorman JH, Sacks MS. On the effects of leaflet microstructure and constitutive model on the closing behavior of the mitral valve. Biomech Model Mechanobiol 2015; 14:1281-302. [PMID: 25947879 PMCID: PMC4881393 DOI: 10.1007/s10237-015-0674-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/01/2015] [Indexed: 12/30/2022]
Abstract
Recent long-term studies showed an unsatisfactory recurrence rate of severe mitral regurgitation 3-5 years after surgical repair, suggesting that excessive tissue stresses and the resulting strain-induced tissue failure are potential etiological factors controlling the success of surgical repair for treating mitral valve (MV) diseases. We hypothesized that restoring normal MV tissue stresses in MV repair techniques would ultimately lead to improved repair durability through the restoration of MV normal homeostatic state. Therefore, we developed a micro- and macro- anatomically accurate MV finite element model by incorporating actual fiber microstructural architecture and a realistic structure-based constitutive model. We investigated MV closing behaviors, with extensive in vitro data used for validating the proposed model. Comparative and parametric studies were conducted to identify essential model fidelity and information for achieving desirable accuracy. More importantly, for the first time, the interrelationship between the local fiber ensemble behavior and the organ-level MV closing behavior was investigated using a computational simulation. These novel results indicated not only the appropriate parameter ranges, but also the importance of the microstructural tuning (i.e., straightening and re-orientation) of the collagen/elastin fiber networks at the macroscopic tissue level for facilitating the proper coaptation and natural functioning of the MV apparatus under physiological loading at the organ level. The proposed computational model would serve as a logical first step toward our long-term modeling goal-facilitating simulation-guided design of optimal surgical repair strategies for treating diseased MVs with significantly enhanced durability.
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Affiliation(s)
- Chung-Hao Lee
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, 201 East 24th Street, 1 University Station C0200, POB 5.236, Austin, TX, 78712, USA
| | - Jean-Pierre Rabbah
- Cardiovascular Fluid Mechanics Laboratory, Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle NW, Atlanta, GA, 30318, USA
| | - Ajit P Yoganathan
- Cardiovascular Fluid Mechanics Laboratory, Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle NW, Atlanta, GA, 30318, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Michael S Sacks
- W. A. "Tex" Moncrief, Jr. Simulation-Based Engineering Science Chair I, Department of Biomedical Engineering, Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, 201 East 24th Street, 1 University Station C0200, POB 5.236, Austin, TX, 78712, USA.
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Ropcke DM, Ilkjær C, Skov SN, Tjørnild MJ, Sørensen AV, Jensen H, Jensen MOJ, Hjortdal VE, Nielsen SL. Functional and Biomechanical Performance of Stentless Extracellular Matrix Tricuspid Tube Graft: An Acute Experimental Porcine Evaluation. Ann Thorac Surg 2015; 101:125-32. [PMID: 26365673 DOI: 10.1016/j.athoracsur.2015.06.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 06/03/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Stentless porcine extracellular matrix tricuspid tubular valves have been developed for tricuspid valve reconstruction. The purpose of this study was to compare biomechanical and functional performance of native and tube graft valves in an acute porcine model. METHODS Twenty-two 65-kg pigs were randomized to tube graft or control with native valve preservation. Anterior papillary muscle force was measured with a dedicated force transducer. Microtip pressure catheters were placed in the right atrium and ventricle. Leaflet motion and three-dimensional valve geometry were evaluated using 13 sonomicrometry crystals: six in the tricuspid annulus, one on each leaflet free edge, one on each papillary muscle tip, and one in the right ventricular apex. RESULTS No regurgitation and no significant differences in intracavitary pressures, annular motion, or leaflet excursion angles were observed after tube graft implantation (p > 0.05). Compared with the native valve, the tricuspid annulus, leaflet orifice area, annular diameters, and the septal segment of the annulus were significantly smaller in the tube graft group (p < 0.05). Maximum anterior papillary muscle force was significantly lower in the tube graft group (p < 0.005). The implantation technique led to an annular circumferential downsizing of 20% ± 17%. CONCLUSIONS An extracellular matrix tube graft implanted in the tricuspid position produces a competent valve with physiologic performance that, despite downsizing, makes the tube graft an attractive alternative to valve replacement. The downsizing of the implantation should be considered when planning tube graft size and may be potentially beneficial by relieving tension on the repaired tissue, thereby increasing durability.
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Affiliation(s)
- Diana M Ropcke
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark.
| | - Christine Ilkjær
- Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Søren N Skov
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Marcell J Tjørnild
- Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Anders V Sørensen
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Henrik Jensen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Morten O J Jensen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark; Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia
| | - Vibeke E Hjortdal
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | - Sten L Nielsen
- Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, and Cardiology, Aarhus University Hospital, Aarhus, Denmark
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Ben Zekry S, Jain S, Alexander S, Li Y, Aggarwal A, Jajoo A, Little S, Lawrie G, Azencott R, Zoghbi W. Novel parameters of global and regional mitral annulus geometry in man: comparison between normals and organic mitral regurgitation, before and after mitral valve repair. Eur Heart J Cardiovasc Imaging 2015; 17:447-57. [DOI: 10.1093/ehjci/jev187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/28/2015] [Indexed: 01/08/2023] Open
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Bouma W, Aoki C, Vergnat M, Pouch AM, Sprinkle SR, Gillespie MJ, Mariani MA, Jackson BM, Gorman RC, Gorman JH. Saddle-Shaped Annuloplasty Improves Leaflet Coaptation in Repair for Ischemic Mitral Regurgitation. Ann Thorac Surg 2015; 100:1360-6. [PMID: 26184554 DOI: 10.1016/j.athoracsur.2015.03.096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 03/26/2015] [Accepted: 03/30/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Current repair results for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings are characterized by high IMR recurrence rates. Current annuloplasty rings treat annular dilatation, but they do little to improve (and may actually exacerbate) leaflet tethering. New saddle-shaped annuloplasty rings have been shown to maintain or restore a more physiologic annular and leaflet geometry and function. Using a porcine IMR model, we sought to demonstrate the influence of annuloplasty ring shape on leaflet coaptation. METHODS Eight weeks after posterolateral infarct, eight pigs with grade 2+ or higher IMR were randomized to undergo either a 28-mm flat ring annuloplasty (n = 4) or a 28-mm saddle-shaped ring annuloplasty (n = 4). Real-time three-dimensional echocardiography and a customized image analysis protocol allowed three-dimensional assessment of leaflet coaptation before and after annuloplasty. RESULTS Total leaflet coaptation area was significantly higher after saddle-shaped ring annuloplasty (109.6 ± 26.9 mm(2)) compared with flat ring annuloplasty (46.2 ± 7.7 mm(2), p <0.01). After annuloplasty, total coaptation area decreased by 87.5 mm(2) (or 65%) in the flat annuloplasty group (p = 0.01), whereas total coaptation area increased by 22.2 mm(2) (or 25%) in the saddle-shaped annuloplasty group (p = 0.28). CONCLUSIONS This study shows that the use of undersized saddle-shaped annuloplasty rings in mitral valve repair for IMR improves leaflet coaptation, whereas the use of undersized flat annuloplasty rings worsens leaflet coaptation. Because one of Carpentier's fundamental principles of mitral valve repair (durability) is to create a large surface of coaptation, saddle-shaped annuloplasty may increase repair durability.
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Affiliation(s)
- Wobbe Bouma
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; University of Groningen, University Medical Center Groningen, Department of Cardiothoracic Surgery, Groningen, Netherlands
| | - Chikashi Aoki
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mathieu Vergnat
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alison M Pouch
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Shanna R Sprinkle
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Matthew J Gillespie
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Massimo A Mariani
- University of Groningen, University Medical Center Groningen, Department of Cardiothoracic Surgery, Groningen, Netherlands
| | - Benjamin M Jackson
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania.
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Malinowski M, Wilton P, Khaghani A, Langholz D, Hooker V, Eberhart L, Hooker RL, Timek TA. The effect of pulmonary hypertension on ovine tricuspid annular dynamics. Eur J Cardiothorac Surg 2015; 49:40-5. [PMID: 25755186 DOI: 10.1093/ejcts/ezv052] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 01/12/2015] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Pulmonary hypertension (PHT) is associated with tricuspid annular dilatation, but the effect of acute increase of pulmonary pressure on three-dimensional (3D) tricuspid annular dynamics and shape is unknown. Better understanding of tricuspid annular dynamics may lead to improved and more durable surgical reparative techniques. METHODS In nine open-chest anaesthetized sheep nine sonomicrometry crystals were implanted on the right ventricle while on cardiopulmonary bypass. Additional nine crystals were implanted around the tricuspid annulus (TA) with one crystal at each commissure defining three separate annular regions: anterior, posterior and septal. Two additional equidistant crystals were implanted between each commissure, creating three segments for every region. Pressure transducers were placed in the left ventricular (LV), right ventricular (RV) and right atrium. PHT was induced by acute pulmonary artery constriction with a pneumatic occluder. Sonomicrometry and echocardiographic data were collected before and after induction of PHT. TA area, regional and total perimeter, and 3D annular geometry were calculated from 3D crystal coordinates. Regional annular contraction was defined as the percentage difference between maximal and minimal region length during the cardiac cycle. RESULTS PHT increased RV pressure from 31 ± 9 mmHg to 46 ± 13 mmHg (P = 0.001) and decreased left ventricular (LV) pressure from 111 ± 24 mmHg to 78 ± 36 mmHg (P = 0.018). There was no significant tricuspid regurgitation observed with PHT. During PHT, the TA area increased by 12 ± 13% from 641 ± 139 mm(2) to 721 ± 177 mm(2) (P = 0.037). The total perimeter increased from 103 ± 11 mm to 109 ± 13 mm (P = 0.02). All annular regions dilated significantly with PHT with 8 ± 10, 5 ± 5 and 5 ± 5% increase in anterior, posterior and septal annular length, respectively (P < 0.05). PHT reduced regional annular contraction in the anterior region only (17 ± 7 vs 14 ± 8%; P = 0.02). The TA had a complex 3D saddle geometry and the shape of the annulus was altered during PHT only in the antero-posterior region. CONCLUSIONS The changes in tricuspid annular conformation, contractility and its 3D geometry observed during acute ovine PHT may help in the design of new pathology-specific tricuspid annular rings.
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Affiliation(s)
- Marcin Malinowski
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland
| | - Penny Wilton
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Asghar Khaghani
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - David Langholz
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Victoria Hooker
- Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland
| | - Lenora Eberhart
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Robert L Hooker
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Tomasz A Timek
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
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Dal-Bianco JP, Beaudoin J, Handschumacher MD, Levine RA. Basic mechanisms of mitral regurgitation. Can J Cardiol 2014; 30:971-81. [PMID: 25151282 DOI: 10.1016/j.cjca.2014.06.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 06/16/2014] [Accepted: 06/22/2014] [Indexed: 12/17/2022] Open
Abstract
Any structural or functional impairment of the mitral valve (MV) apparatus that exhausts MV tissue redundancy available for leaflet coaptation will result in mitral regurgitation (MR). The mechanism responsible for MV malcoaptation and MR can be dysfunction or structural change of the left ventricle, the papillary muscles, the chordae tendineae, the mitral annulus, and the MV leaflets. The rationale for MV treatment depends on the MR mechanism and therefore it is essential to identify and understand normal and abnormal MV and MV apparatus function.
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Affiliation(s)
- Jacob P Dal-Bianco
- Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jonathan Beaudoin
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Department of Cardiology, Québec City, Québec, Canada
| | - Mark D Handschumacher
- Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert A Levine
- Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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Lee CH, Amini R, Gorman RC, Gorman JH, Sacks MS. An inverse modeling approach for stress estimation in mitral valve anterior leaflet valvuloplasty for in-vivo valvular biomaterial assessment. J Biomech 2014; 47:2055-63. [PMID: 24275434 PMCID: PMC4014535 DOI: 10.1016/j.jbiomech.2013.10.058] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/18/2013] [Accepted: 10/19/2013] [Indexed: 11/16/2022]
Abstract
Estimation of regional tissue stresses in the functioning heart valve remains an important goal in our understanding of normal valve function and in developing novel engineered tissue strategies for valvular repair and replacement. Methods to accurately estimate regional tissue stresses are thus needed for this purpose, and in particular to develop accurate, statistically informed means to validate computational models of valve function. Moreover, there exists no currently accepted method to evaluate engineered heart valve tissues and replacement heart valve biomaterials undergoing valvular stresses in blood contact. While we have utilized mitral valve anterior leaflet valvuloplasty as an experimental approach to address this limitation, robust computational techniques to estimate implant stresses are required. In the present study, we developed a novel numerical analysis approach for estimation of the in-vivo stresses of the central region of the mitral valve anterior leaflet (MVAL) delimited by a sonocrystal transducer array. The in-vivo material properties of the MVAL were simulated using an inverse FE modeling approach based on three pseudo-hyperelastic constitutive models: the neo-Hookean, exponential-type isotropic, and full collagen-fiber mapped transversely isotropic models. A series of numerical replications with varying structural configurations were developed by incorporating measured statistical variations in MVAL local preferred fiber directions and fiber splay. These model replications were then used to investigate how known variations in the valve tissue microstructure influence the estimated ROI stresses and its variation at each time point during a cardiac cycle. Simulations were also able to include estimates of the variation in tissue stresses for an individual specimen dataset over the cardiac cycle. Of the three material models, the transversely anisotropic model produced the most accurate results, with ROI averaged stresses at the fully-loaded state of 432.6±46.5 kPa and 241.4±40.5 kPa in the radial and circumferential directions, respectively. We conclude that the present approach can provide robust instantaneous mean and variation estimates of tissue stresses of the central regions of the MVAL.
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Affiliation(s)
- Chung-Hao Lee
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, ACES 5.236, 1 University Station C0200, Austin, TX 78712, USA
| | - Rouzbeh Amini
- Department of Biomedical Engineering, The University of Akron, Auburn Science and Engineering Center 275, West Tower, Akron, OH 44325, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Michael S Sacks
- Center for Cardiovascular Simulation, Institute for Computational Engineering and Sciences (ICES), Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, ACES 5.236, 1 University Station C0200, Austin, TX 78712, USA.
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Abstract
AIMS To evaluate the role of torsion in hypertrophic cardiomyopathy in children. METHODS A total of 88 children with idiopathic hypertrophic cardiomyopathy (n = 24) and concentric hypertrophy (n = 20) were investigated with speckle-tracking echocardiography and compared with age- and gender-matched healthy controls (n = 44). RESULTS In hypertrophic cardiomyopathy, we found increased torsion (2.8 ± 1.6 versus 1.9 ± 1.0°/cm [controls], p < 0.05) because of an increase in clockwise basal rotation (-8.7 ± 4.3° versus -4.9 ± 2.5° [controls], p < 0.001) and prolonged time to peak diastolic untwisting (3.7 ± 2.4% versus 1.7 ± 0.6% [controls] of cardiac cycle, p < 0.01), but no differences in peak untwisting velocities. Hypertrophic cardiomyopathy patients demonstrated a negative correlation between left ventricular muscle mass and torsion (r = -0.7, p < 0.001). In concentric hypertrophy, torsion was elevated because of increased apical rotation (15.1 ± 6.4° versus 10.5 ± 5.5° [controls], p < 0.05) without correlation with muscle mass. Peak untwisting velocities (- 202 ± 88 versus -145 ± 67°/s [controls], p < 0.05) were higher in concentric hypertrophy and time to peak diastolic untwisting was delayed (1.8 ± 0.8% versus 1.2 ± 0.6% [controls], p < 0.05). CONCLUSIONS In contrast to an increased counterclockwise apical rotation in concentric hypertrophy, hypertrophic cardiomyopathy is characterised by predominantly enhanced systolic basal clockwise rotation. Diastolic untwisting is delayed in both groups. Torsion may be an interesting marker to guide patients with hypertrophic cardiomyopathy.
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Pouch AM, Vergnat M, McGarvey JR, Ferrari G, Jackson BM, Sehgal CM, Yushkevich PA, Gorman RC, Gorman JH. Statistical assessment of normal mitral annular geometry using automated three-dimensional echocardiographic analysis. Ann Thorac Surg 2013; 97:71-7. [PMID: 24090576 DOI: 10.1016/j.athoracsur.2013.07.096] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 07/24/2013] [Accepted: 07/29/2013] [Indexed: 11/18/2022]
Abstract
BACKGROUND The basis of mitral annuloplasty ring design has progressed from qualitative surgical intuition to experimental and theoretical analysis of annular geometry with quantitative imaging techniques. In this work, we present an automated three-dimensional (3D) echocardiographic image analysis method that can be used to statistically assess variability in normal mitral annular geometry to support advancement in annuloplasty ring design. METHODS Three-dimensional patient-specific models of the mitral annulus were automatically generated from 3D echocardiographic images acquired from subjects with normal mitral valve structure and function. Geometric annular measurements including annular circumference, annular height, septolateral diameter, intercommissural width, and the annular height to intercommissural width ratio were automatically calculated. A mean 3D annular contour was computed, and principal component analysis was used to evaluate variability in normal annular shape. RESULTS The following mean ± standard deviations were obtained from 3D echocardiographic image analysis: annular circumference, 107.0 ± 14.6 mm; annular height, 7.6 ± 2.8 mm; septolateral diameter, 28.5 ± 3.7 mm; intercommissural width, 33.0 ± 5.3 mm; and annular height to intercommissural width ratio, 22.7% ± 6.9%. Principal component analysis indicated that shape variability was primarily related to overall annular size, with more subtle variation in the skewness and height of the anterior annular peak, independent of annular diameter. CONCLUSIONS Patient-specific 3D echocardiographic-based modeling of the human mitral valve enables statistical analysis of physiologically normal mitral annular geometry. The tool can potentially lead to the development of a new generation of annuloplasty rings that restore the diseased mitral valve annulus back to a truly normal geometry.
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Affiliation(s)
- Alison M Pouch
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania; Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mathieu Vergnat
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jeremy R McGarvey
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Giovanni Ferrari
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Benjamin M Jackson
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chandra M Sehgal
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Paul A Yushkevich
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
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50
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Askov JB, Honge JL, Jensen MO, Nygaard H, Hasenkam JM, Nielsen SL. Significance of force transfer in mitral valve–left ventricular interaction: In vivo assessment. J Thorac Cardiovasc Surg 2013; 145:1635-41, 1641.e1. [DOI: 10.1016/j.jtcvs.2012.07.062] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/10/2012] [Accepted: 07/26/2012] [Indexed: 11/26/2022]
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