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El-Nashar H, Sabry M, Tseng YT, Francis N, Latif N, Parker KH, Moore JE, Yacoub MH. Multiscale structure and function of the aortic valve apparatus. Physiol Rev 2024; 104:1487-1532. [PMID: 37732828 DOI: 10.1152/physrev.00038.2022] [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: 12/07/2022] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/22/2023] Open
Abstract
Whereas studying the aortic valve in isolation has facilitated the development of life-saving procedures and technologies, the dynamic interplay of the aortic valve and its surrounding structures is vital to preserving their function across the wide range of conditions encountered in an active lifestyle. Our view is that these structures should be viewed as an integrated functional unit, here referred to as the aortic valve apparatus (AVA). The coupling of the aortic valve and root, left ventricular outflow tract, and blood circulation is crucial for AVA's functions: unidirectional flow out of the left ventricle, coronary perfusion, reservoir function, and support of left ventricular function. In this review, we explore the multiscale biological and physical phenomena that underlie the simultaneous fulfillment of these functions. A brief overview of the tools used to investigate the AVA, such as medical imaging modalities, experimental methods, and computational modeling, specifically fluid-structure interaction (FSI) simulations, is included. Some pathologies affecting the AVA are explored, and insights are provided on treatments and interventions that aim to maintain quality of life. The concepts explained in this article support the idea of AVA being an integrated functional unit and help identify unanswered research questions. Incorporating phenomena through the molecular, micro, meso, and whole tissue scales is crucial for understanding the sophisticated normal functions and diseases of the AVA.
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Affiliation(s)
- Hussam El-Nashar
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Malak Sabry
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Department of Biomedical Engineering, King's College London, London, United Kingdom
| | - Yuan-Tsan Tseng
- Heart Science Centre, Magdi Yacoub Institute, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Nadine Francis
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Najma Latif
- Heart Science Centre, Magdi Yacoub Institute, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Kim H Parker
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - James E Moore
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Magdi H Yacoub
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Heart Science Centre, Magdi Yacoub Institute, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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2
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Zhang W, Jadidi M, Razian SA, Holzapfel GA, Kamenskiy A, Nordsletten DA. A Viscoelastic Constitutive Framework for Aging Muscular and Elastic Arteries. Acta Biomater 2024:S1742-7061(24)00534-8. [PMID: 39303831 DOI: 10.1016/j.actbio.2024.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 09/11/2024] [Accepted: 09/12/2024] [Indexed: 09/22/2024]
Abstract
The evolution of arterial biomechanics and microstructure with age and disease plays a critical role in understanding the health and function of the cardiovascular system. Accurately capturing these adaptative processes and their effects on the mechanical environment is critical for predicting arterial responses. This challenge is exacerbated by the significant differences between elastic and muscular arteries, which have different structural organizations and functional demands. In this study, we aim to shed light to these adaptive processes by comparing the viscoelastic mechanics of autologous thoracic aortas (TA) and femoropopliteal arteries (FPA) in different age groups. We have extended our fractional viscoelastic framework, originally developed for FPA, to both types of arteries. To evaluate this framework, we analyzed experimental mechanical data from TA and FPA specimens from 21 individuals aged 13 to 73 years. Each specimen was subjected to a multi-ratio biaxial mechanical extension and relaxation test complemented by bidirectional histology to quantify the structural density and microstructural orientations. Our new constitutive model accurately captured the mechanical responses and microstructural differences of the tissues and closely matched the experimentally measured densities. It was found that the viscoelastic properties of collagen and smooth muscle cells (SMCs) in both the FPA and TA remained consistent with age, but the viscoelasticity of the SMCs in the FPA was twice that of the TA. Additionally, changes in collagen nonlinearity with age were similar in both TA and FPA. This model provides valuable insights into arterial mechanophysiology and the effects of pathological conditions on vascular biomechanics. STATEMENT OF SIGNIFICANCE: Developing durable treatments for arterial diseases necessitates a deeper understanding of how mechanical properties evolve with age in response to mechanical environments. In this work, we developed a generalized viscoelastic constitutive model for both elastic and muscular arteries and analyzed both the thoracic aorta (TA) and the femoropopliteal artery (FPA) from 21 donors aged 13 to 73. The derived parameters correlate well with histology, allowing further examination of how viscoelasticity evolves with age. Correlation between the TA and FPA of the same donors suggest that the viscoelasticity of the FPA may be influenced by the TA, necessitating more detailed analysis. In summary, our new model proves to be a valuable tool for studying arterial mechanophysiology and exploring pathological impacts.
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Affiliation(s)
- Will Zhang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - Majid Jadidi
- Department of Biomechanics, University of Nebraska at Omaha, NE, USA.
| | | | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Austria; Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Alexey Kamenskiy
- Department of Biomechanics, University of Nebraska at Omaha, NE, USA.
| | - David A Nordsletten
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Division of Biomedical Engineering and Imaging Sciences, Department of Biomedical Engineering, King's College London, UK.
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3
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Sempértegui F, Avril S. Integration of cross-links, discrete fiber distributions and of a non-local theory in the Homogenized Constrained Mixture Model to Simulate Patient-Specific Thoracic Aortic Aneurysm Progression. J Biomech 2024:112297. [PMID: 39244434 DOI: 10.1016/j.jbiomech.2024.112297] [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: 03/31/2024] [Revised: 07/28/2024] [Accepted: 08/26/2024] [Indexed: 09/09/2024]
Abstract
Thoracic aortic aneurysms (TAA) represent a critical health issue for which computational models can significantly contribute to better understand the physiopathology. Among different computational frameworks, the Homogenized Constrained Mixture Theory has shown to be a computationally efficient option, allowing the inclusion of several mechanically significant constituents into a layer-specific mixture. Different patient-specific Growth and Remodeling (G&R) models correctly predicted TAA progression, although simplifications such as the inclusion of a limited number of collagen fibers and imposed boundary conditions might limit extensive analyses. The current study aims to enhance existing models by incorporating several discrete collagen fibers and to remove restrictive boundary conditions of the previous models. The implementation of discretized fiber dispersion presents a more realistic description of the vessel, while the removal of boundary conditions was addressed by including cross-links in the model to provide a supplemental stiffness against through-thickness shearing, a feature that was previously absent, and by the development of a non-local framework that ensures the stable deposition and degradation of collagen fibers. With these improvements, the current model represents a step forward towards more robust and comprehensive simulations of TAA growth.
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Affiliation(s)
- Felipe Sempértegui
- Mines Saint-Étienne, Univ Jean Monnet, INSERM, U 1059 Sainbiose, F - 42023, Saint-Étienne, France.
| | - Stéphane Avril
- Mines Saint-Étienne, Univ Jean Monnet, INSERM, U 1059 Sainbiose, F - 42023, Saint-Étienne, France.
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4
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Sun Z, Mi C. Biomechanics of annulus fibrosus: Elastic fiber simplification and degenerative impact on damage initiation and propagation. J Mech Behav Biomed Mater 2024; 157:106628. [PMID: 38878651 DOI: 10.1016/j.jmbbm.2024.106628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 05/19/2024] [Accepted: 06/08/2024] [Indexed: 07/30/2024]
Abstract
This study addresses three primary objectives related to lumbar intervertebral disc (IVD) biomechanics under ramping quasi-static loading conditions. First, we explore the conditions justifying the simplification of axisymmetric elastic fiber families into single fiber bundles through discretized strain energy functions. Simulations reveal that a concentration factor exceeding 10 allows for a consistent deviation below 10% between simplified and non-simplified responses. Second, we investigate the impact of elastic fibers on the physiological stiffness in IVDs, revealing minimal influence on biological motions but significant effects on degeneration. Lastly, we examine the initiation and progression of annulus fibrosus (AF) damage. Our findings confirm the validity of simplifying elastic fiber families and underscore the necessity of considering elastic fiber damage in biomechanical studies of AF tissues. Elastic fibers contribute to increased biaxial stretch stiffness, and their damage significantly affects the loading capacity of the inner AF. Additionally, degeneration significantly alters the susceptibility to damage in the AF, with specific regions exhibiting higher vulnerability. Damage tends to extend circumferentially and radially, emphasizing the regional variations in collagen and elastic fiber properties. This study offers useful insights for refining biomechanical models, paving the way for a more comprehensive understanding of IVD responses and potential clinical implications.
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Affiliation(s)
- Zhongwei Sun
- Jiangsu Key Laboratory of Mechanical Analysis for Infrastructure and Advanced Equipment, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Changwen Mi
- Jiangsu Key Laboratory of Mechanical Analysis for Infrastructure and Advanced Equipment, School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China.
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5
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Armfield D, Boxwell S, McNamara L, Cook S, Conway S, Celikin M, Cardiff P. Effect of bioprosthetic leaflet anisotropy on stent dynamics of Transcatheter Aortic Valve Replacement devices. J Mech Behav Biomed Mater 2024; 157:106650. [PMID: 39018917 DOI: 10.1016/j.jmbbm.2024.106650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 06/28/2024] [Accepted: 07/01/2024] [Indexed: 07/19/2024]
Abstract
The assessment of stent fatigue in Transcatheter Aortic Valve Replacement (TAVR) systems is critical for the design of next-generation devices, both in vitro and in vivo. The mechanical properties of the bioprosthetic heart valves (BHVs) have a significant impact on the fatigue life of the metallic stent and thus must be taken into consideration when evaluating new TAVR device designs. This study aims to investigate the relationship between BHV anisotropic behaviour and the asymmetric deflections of the stent frame observed during in vitro testing. An explicit dynamics finite element model of the nitinol stent with attached bioprosthetic valve leaflets was developed to evaluate the deflections of the TAVR device under haemodynamic loading. Our results demonstrate that pericardium behaviour plays a dominant role in determining stent frame deflection. The anisotropic behaviour of the leaflets, resulting from collagen fibre orientation, affects the extent of deflection encountered by each commissure of the frame. This leads to asymmetric variation in frame deflection that can influence the overall fatigue life of the nitinol stent. This study highlights the importance of considering both the flexible nature of the metallic stent as well as the leaflet anisotropic behaviour in the design and fatigue assessment of TAVR systems.
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Affiliation(s)
- Dylan Armfield
- School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland; SFI I-Form Centre, University College Dublin, Dublin, Ireland.
| | - Sam Boxwell
- School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland; Mechanobiology and Medical Device Research Group, Department of Biomedical Engineering, University of Galway, Galway, Ireland
| | - Laoise McNamara
- Mechanobiology and Medical Device Research Group, Department of Biomedical Engineering, University of Galway, Galway, Ireland
| | - Scott Cook
- Structural Heart Division, Boston Scientific Corporation, Galway, Ireland
| | - Shane Conway
- Structural Heart Division, Boston Scientific Corporation, Galway, Ireland
| | - Mert Celikin
- School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland; SFI I-Form Centre, University College Dublin, Dublin, Ireland
| | - Philip Cardiff
- School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland; SFI I-Form Centre, University College Dublin, Dublin, Ireland.
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6
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Parikh S, Giudici A, Huberts W, Delhaas T, Bidar E, Spronck B, Reesink K. Significance of Dynamic Axial Stretching on Estimating Biomechanical Behavior and Properties of the Human Ascending Aorta. Ann Biomed Eng 2024; 52:2485-2495. [PMID: 38836979 PMCID: PMC11329543 DOI: 10.1007/s10439-024-03537-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 05/02/2024] [Indexed: 06/06/2024]
Abstract
Contrary to most vessels, the ascending thoracic aorta (ATA) not only distends but also elongates in the axial direction. The purpose of this study is to investigate the biomechanical behavior of the ascending thoracic aorta (ATA) in response to dynamic axial stretching during the cardiac cycle. In addition, the implications of neglecting this dynamic axial stretching when estimating the constitutive model parameters of the ATA are investigated. The investigations were performed through in silico simulations by assuming a Gasser-Ogden-Holzapfel (GOH) constitutive model representative of ATA tissue material. The GOH model parameters were obtained from biaxial tests performed on four human ATA tissues in a previous study. Pressure-diameter curves were simulated as synthetic data to assess the effect of neglecting dynamic axial stretching on estimating constitutive model parameters. Our findings reveal a significant increase in axial stress (~ 16%) and stored strain energy (~ 18%) in the vessel when dynamic axial stretching is considered, as opposed to assuming a fixed axial stretch. All but one artery showed increased volume compliance while considering a dynamic axial stretching condition. Furthermore, we observe a notable difference in the estimated constitutive model parameters when dynamic axial stretching of the ATA is neglected, compared to the ground truth model parameters. These results underscore the critical importance of accounting for axial deformations when conducting in vivo biomechanical characterization of the ascending thoracic aorta.
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Affiliation(s)
- Shaiv Parikh
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Alessandro Giudici
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- GROW School for Oncology and Reproduction, Maastricht University, Maastricht, The Netherlands
| | - Wouter Huberts
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Department of Biomedical Engineering, Cardiovascular Biomechanics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Tammo Delhaas
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Elham Bidar
- Department of Cardiothoracic Surgery, Heart & Vascular Centre, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Bart Spronck
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie University, Sydney, Australia
| | - Koen Reesink
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands.
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7
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Milakovic L, Dandois F, Fehervary H, Scheys L. Calibration of Holzapfel-Gasser-Ogden collateral ligament properties in a hybrid post-arthroplasty knee joint model for laxity testing. Comput Methods Biomech Biomed Engin 2024; 27:1680-1690. [PMID: 37668078 DOI: 10.1080/10255842.2023.2253950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/10/2023] [Accepted: 08/21/2023] [Indexed: 09/06/2023]
Abstract
Knee collateral ligaments play a vital role in providing frontal-plane stability in post-total knee arthroplasty (TKA) knees. Finite element models can utilize computationally efficient one-dimensional springs or more physiologically accurate three-dimensional continuum elements like the Holzapfel-Gasser-Ogden (HGO) formulation. However, there is limited literature defining subject-specific mechanical properties, particularly for the HGO model. In this study, we propose a co-simulation framework to obtain subject-specific material parameters for an HGO-based finite element ligament model integrated into a rigid-body model of the post-TKA knee. Our approach achieves comparable accuracy to spring formulations while significantly reducing coefficient calibration time and demonstrating improved correlation with reference knee kinematics and ligament strains throughout the tested loading range.
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Affiliation(s)
- Lucas Milakovic
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, Leuven, KU, Belgium
| | - Félix Dandois
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, Leuven, KU, Belgium
| | - Heleen Fehervary
- Biomechanics Section, Mechanical Engineering Department, KU Leuven, Leuven, Belgium
- FIBEr, KU Leuven Core Facility for Biomechanical Experimentation, Leuven, Belgium
| | - Lennart Scheys
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, Leuven, KU, Belgium
- Division of Orthopaedics, University Hospitals Leuven, Leuven, Belgium
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8
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Garcia M, Landi G, Covan B, Caro D, Khak M, Razavi AH, DeAngelis JP, Ramappa AJ, Nazarian A. Effect of Tear Size and Location on Supraspinatus Tendon Strain During Activities of Daily Living and Physiotherapy. Ann Biomed Eng 2024; 52:2496-2508. [PMID: 39033199 DOI: 10.1007/s10439-024-03538-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 05/06/2024] [Indexed: 07/23/2024]
Abstract
The supraspinatus tendon plays a crucial role in shoulder abduction, making it one of the common structures affected by injury. Clinically, crescent-shaped tears are the most commonly seen tear shape. By developing six specimen-specific, three-dimensional, supraspinatus-infraspinatus finite element model with heterogeneous material properties, this study aimed to examine the changes in tissue deformation (maximum principal strain) of the supraspinatus tendon due to specimen-specific material properties and rotator cuff tear size. FE models with small- and medium-sized full-thickness crescent-shaped tears were subjected to loads seen during activities of daily living and physiotherapy. Six fresh-frozen cadaveric shoulders were dissected to mechanically test the supraspinatus tendon and develop and validate FE models that can be used to assess changes in strain due to small (< 1 cm, equivalent to 20-30% of the tendon width) and medium-sized (1-3 cm, equivalent to 40-50% of the tendon width) tears that are located in the middle and posterior regions of the supraspinatus tendon. FE predictions of maximum principal strain at the tear tips were examined to determine whether failure strain was reached during activities of daily living (drinking and brushing teeth) and physiotherapy exercises (prone abduction and external rotation at 90° abduction). No significant differences were observed between the middle and posterior tear failure loads for small- and medium-sized tears. For prone abduction, there was a potential risk for tear progression (exceeded failure strain) for medium-sized tears in the supraspinatus tendon's middle and posterior regions. For external rotation at 90° abduction, one model with a middle tear and two with posterior tears experienced failure. For all daily activity loads, the strain never exceeded the failure strain. Our three-dimensional supraspinatus-infraspinatus FE model shows that small tears appear unlikely to progress based on the regional strain response; however, medium-sized tears are at higher risk during more strenuous physiotherapy exercises. Furthermore, differences in patient-specific tendon material properties are important in determining whether the tear will progress. Therefore, patient-specific management plans based on tear size may be beneficial to improve clinical outcomes.
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Affiliation(s)
- Mason Garcia
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
- Mechanical Engineering Department, Boston University, Boston, MA, USA
| | - Gabriel Landi
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
| | - Bailee Covan
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
| | - Daniela Caro
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
| | - Mohammad Khak
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
- Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ahmad Hedayatzadeh Razavi
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
- Mechanical Engineering Department, Boston University, Boston, MA, USA
| | - Joseph P DeAngelis
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
- Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Arun J Ramappa
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA
- Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ara Nazarian
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN123, Boston, MA, 02115, USA.
- Mechanical Engineering Department, Boston University, Boston, MA, USA.
- Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
- Department of Orthopaedic Surgery, Yerevan State Medical University, Yerevan, Armenia.
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9
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Nelson TM, Mariano CA, Ramirez GO, Badrou A, Quiros KAM, Shankel M, Eskandari M. Lung Mechanics: Material Characterization of Pulmonary Constituents for an Experimentally Informed Computational Pipeline. Curr Protoc 2024; 4:e70001. [PMID: 39240156 DOI: 10.1002/cpz1.70001] [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] [Indexed: 09/07/2024]
Abstract
The lung comprises multiple components including the parenchyma, airways, and visceral pleura, where each constituent displays specific material properties that together govern the whole organ's properties. The structural and mechanical complexity of the lung has historically undermined its comprehensive characterization, especially compared to other biological organs, such as the heart or bones. This knowledge void is particularly remarkable when considering that pulmonary disease is one of the leading causes of morbidity and mortality across the globe. Establishing the mechanical properties of the lung is central to formulating a baseline understanding of its operation, which can facilitate investigations of diseased states and how the lung will potentially respond to clinical interventions. Here, we present established and widely accepted experimental protocols for pulmonary material quantification, specifying how to extract, prepare, and test each type of lung constituent under planar biaxial tensile loading to investigate the mechanical properties, such as physiological stress-strain profiles, anisotropy, and viscoelasticity. These methods are presented across an array of commonly studied species (murine, rat, and porcine). Additionally, we highlight how such material properties may inform the construction of an inverse finite element model, which is central to implementing predictive computational tools for accurate disease diagnostics and optimized medical treatments. These presented methodologies are aimed at supporting research advancements in the field of pulmonary biomechanics and to help inaugurate future novel studies. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: General procedures in lung biaxial testing Alternate Protocol 1: Parenchymal-specific preparation and loading procedures Alternate Protocol 2: Airway-specific preparation and loading procedures Alternate Protocol 3: Visceral pleura-specific preparation and loading procedures Basic Protocol 2: Computational analysis.
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Affiliation(s)
- Talyah M Nelson
- Department of Mechanical Engineering, University of California, Riverside, California
| | - Crystal A Mariano
- Department of Mechanical Engineering, University of California, Riverside, California
| | - Gustavo O Ramirez
- Department of Mechanical Engineering, University of California, Riverside, California
| | - Arif Badrou
- Department of Mechanical Engineering, University of California, Riverside, California
| | - Kathrine A M Quiros
- Department of Mechanical Engineering, University of California, Riverside, California
| | - Matthew Shankel
- Department of Mechanical Engineering, University of California, Riverside, California
| | - Mona Eskandari
- Department of Mechanical Engineering, University of California, Riverside, California
- BREATHE Center, School of Medicine University of California, Riverside, California
- Department of Bioengineering, University of California, Riverside, California
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10
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Khaledian N, Villard PF, Hammer PE, Perrin DP, Berger MO. Image-based simulation of mitral valve dynamic closure including anisotropy. Med Image Anal 2024; 99:103323. [PMID: 39243597 DOI: 10.1016/j.media.2024.103323] [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: 01/31/2024] [Revised: 07/10/2024] [Accepted: 08/20/2024] [Indexed: 09/09/2024]
Abstract
Simulation of the dynamic behavior of mitral valve closure could improve clinical treatment by predicting surgical procedures outcome. We propose here a method to achieve this goal by using the immersed boundary method. In order to go towards patient-based simulation, we tailor our method to be adapted to a valve extracted from medical image data. It includes investigating segmentation process, smoothness of geometry, case setup and the shape of the left ventricle. We also study the influence of leaflet tissue anisotropy on the quality of the valve closure by comparing with an isotropic model. As part of the anisotropy analysis, we study the influence of the principal material direction by comparing methods to obtain them without dissection. Results show that our method can be scaled to various image-based data. We evaluate the mitral valve closure quality based on measuring bulging area, contact map, and flow rate. The results show also that the anisotropic material model more precisely represents the physiological characteristics of the valve tissue. Furthermore, results indicate that the orientation of the principal material direction plays a role in the effectiveness of the valve seal.
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Affiliation(s)
| | | | - Peter E Hammer
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Douglas P Perrin
- Department of Cardiac Surgery, Boston Children's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
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11
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Yin Z, Armour C, Kandail H, O'Regan DP, Bahrami T, Mirsadraee S, Pirola S, Xu XY. Fluid-structure interaction analysis of a healthy aortic valve and its surrounding haemodynamics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024:e3865. [PMID: 39209425 DOI: 10.1002/cnm.3865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 07/23/2024] [Accepted: 08/17/2024] [Indexed: 09/04/2024]
Abstract
The opening and closing dynamics of the aortic valve (AV) has a strong influence on haemodynamics in the aortic root, and both play a pivotal role in maintaining normal physiological functions of the valve. The aim of this study was to establish a subject-specific fluid-structure interaction (FSI) workflow capable of simulating the motion of a tricuspid healthy valve and the surrounding haemodynamics under physiologically realistic conditions. A subject-specific aortic root was reconstructed from magnetic resonance (MR) images acquired from a healthy volunteer, whilst the valve leaflets were built using a parametric model fitted to the subject-specific aortic root geometry. The material behaviour of the leaflets was described using the isotropic hyperelastic Ogden model, and subject-specific boundary conditions were derived from 4D-flow MR imaging (4D-MRI). Strongly coupled FSI simulations were performed using a finite volume-based boundary conforming method implemented in FlowVision. Our FSI model was able to simulate the opening and closing of the AV throughout the entire cardiac cycle. Comparisons of simulation results with 4D-MRI showed a good agreement in key haemodynamic parameters, with stroke volume differing by 7.5% and the maximum jet velocity differing by less than 1%. Detailed analysis of wall shear stress (WSS) on the leaflets revealed much higher WSS on the ventricular side than the aortic side and different spatial patterns amongst the three leaflets.
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Affiliation(s)
- Zhongjie Yin
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Chlöe Armour
- Department of Chemical Engineering, Imperial College London, London, UK
- National Heart and Lung Institute, Imperial College London, London, UK
| | | | - Declan P O'Regan
- Laboratory of Medical Sciences, Imperial College London, London, UK
| | - Toufan Bahrami
- National Heart and Lung Institute, Imperial College London, London, UK
- Department of Cardiothoracic Surgery, Royal Brompton and Harefield Hospitals NHS Trust, London, UK
| | - Saeed Mirsadraee
- National Heart and Lung Institute, Imperial College London, London, UK
- Department of Radiology, Royal Brompton and Harefield Hospitals NHS Trust, London, UK
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, UK
- Department of BioMechanical Engineering, TU Delft, Delft, The Netherlands
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
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12
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Ritzert S, Rjosk A, Holthusen H, Lautenschläger T, Neinhuis C, Reese S. Mechanical modeling of the petiole-lamina transition zone of peltate leaves. Acta Biomater 2024:S1742-7061(24)00463-X. [PMID: 39173697 DOI: 10.1016/j.actbio.2024.08.019] [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: 04/22/2024] [Revised: 08/12/2024] [Accepted: 08/14/2024] [Indexed: 08/24/2024]
Abstract
Plant leaves have to deal with various environmental influences. While the mechanical properties of petiole and lamina are generally well studied, only few studies focused on the properties of the transition zone joining petiole and lamina. Especially in peltate leaves, characterised by the attachment of the petiole to the abaxial side of the lamina, the 3D leaf architecture imposes specific mechanical stresses on the petiole and petiole-lamina transition zone. Several principles of internal anatomical organisation have been identified. Since the mechanical characterisation of the transition zone by direct measurements is difficult, we explored the mechanical properties and load-bearing mechanisms by finite-element simulations. We simulate the petiole-lamina transition zone with five different fibre models that were abstracted from CT data. For comparison, three different load cases were defined and tested in the simulation. In the proposed model, the fibres are represented in a smeared sense, where we considered transverse isotropic behavior in elements containing fibres. In a pre-processing step, we determined the fibre content, direction, and dispersion and fed them into our model. The simulations show that initially, matrix and fibres carry the load together. After relaxation of the stresses in the matrix, the fibres carry most of the load. Load dissipation and stiffness differ according to fibre arrangement and depend, among other things, on orientation and cross-linking of the fibres and fibre amount. Even though the presented method is a simplified approach, it is able to show the different load-bearing capacities of the presented fibre arrangements. STATEMENT OF SIGNIFICANCE: In plant leaves, the petiole-lamina transition zone is an important structural element facilitating water and nutrient transport, as well as load dissipation from the lamina into the petiole. Especially in peltate leaves, the 3D leaf architecture imposes specific mechanical stresses on the petiole-lamina transition zone. This study aims at investigating its mechanical behavior using finite-element simulations. The proposed continuum mechanical anisotropic viscoelastic material model is able to simulate the transition zone under different loads while also considering different fibre arrangements. The simulations highlight the load-bearing mechanisms of different fibre organisations, show the mechanical significance of the petiole-lamina transition zone and can be used in the design of a future biomimetic junction in construction.
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Affiliation(s)
- Stephan Ritzert
- Institute of Applied Mechanics, RWTH Aachen University, Aachen, Germany.
| | - Annabell Rjosk
- Institute of Botany, TUD Dresden University of Technology, Dresden, Germany.
| | - Hagen Holthusen
- Institute of Applied Mechanics, RWTH Aachen University, Aachen, Germany
| | | | - Christoph Neinhuis
- Institute of Botany, TUD Dresden University of Technology, Dresden, Germany
| | - Stefanie Reese
- Institute of Applied Mechanics, RWTH Aachen University, Aachen, Germany; University of Siegen, Siegen, Germany
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13
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Diniz P, Quental C, Pereira H, Lopes R, Kerkhoffs GMMJ, Ferreira FC, Folgado J. Progression of partial to complete ruptures of the Achilles tendon during rehabilitation: A study using a finite element model. J Orthop Res 2024; 42:1670-1681. [PMID: 38472691 DOI: 10.1002/jor.25827] [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: 06/15/2023] [Revised: 12/30/2023] [Accepted: 02/13/2024] [Indexed: 03/14/2024]
Abstract
Substantial research on complete Achilles tendon ruptures is available, but guidance on partial ruptures is comparatively sparse. Conservative management is considered acceptable in partial tendon ruptures affecting less than 50% of the tendon's width, but supporting experimental evidence is currently lacking. Using a previously validated finite element model of the Achilles tendon, this study aimed to assess whether loading conditions simulating an early functional rehabilitation protocol could elicit progression to a complete rupture in partial ruptures of varying severity. In silico tendon rupture simulations were performed to locate the most likely rupture site for least, moderate, and extreme subtendon twist configurations. These three models were split at the corresponding rupture site and two sets of partial ruptures were created for each, starting from the medial and lateral sides, and ranging from 10% to 50% loss of continuity. Simulations were conducted with material parameters from healthy and tendinopathic tendons. Partial ruptures were considered to progress if the volume of elements showing a maximum principal strain above 10% exceeded 3 mm3. To assess whether the tendinopathic tendons typical geometric characteristics could compensate for the inferior material properties found in tendinopathy, an additional model with increased cross-sectional area in the free tendon region was developed. Progression to complete ruptures occurred even with less than a 50% loss of continuity, regardless of subtendon twisting, and material parameters. The tendinopathic tendon model with increased cross-sectional area showed similar results. These findings suggest the current criteria for surgical treatment of partial ruptures should be reconsidered. Statement of clinical significance: The clinical significance and most appropriate treatment of partial ruptures of the Achilles tendon is unclear. Despite the widespread use of the "50% rule" in treatment decisions of partial tendon ruptures, experimental evidence supporting it is missing. The present study provides new data, from a validated aponeurotic and free Achilles tendon finite element model, showing that partial ruptures may progress to complete ruptures under loading conditions elicited from functional rehabilitation protocols, even for partial ruptures affecting less than 50% of the tendon's width. Under these novel findings, the current criteria for surgical treatment of partial ruptures should be reconsidered.
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Affiliation(s)
- Pedro Diniz
- Department of Orthopaedic Surgery, Hospital de Sant'Ana, Parede, Portugal
- Department of Bioengineering and iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Fisiogaspar, Lisboa, Portugal
| | - Carlos Quental
- IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Hélder Pereira
- Orthopaedic Department, Centro Hospitalar Póvoa de Varzim, Vila do Conde, Portugal
- Ripoll y De Prado Sports Clinic: FIFA Medical Centre of Excellence, Murcia-Madrid, Spain
- University of Minho ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Rodrigo Lopes
- Department of Orthopaedic Surgery, Hospital de Sant'Ana, Parede, Portugal
| | - Gino M M J Kerkhoffs
- Department of Orthopaedic Surgery, Amsterdam Movement Sciences, Amsterdam University Medical Centers, Academic Center for Evidence Based Sports Medicine (ACES), Amsterdam Collaboration for Health and Safety in Sports (ACHSS), Amsterdam, The Netherlands
| | - Frederico C Ferreira
- Department of Bioengineering and iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - João Folgado
- IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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14
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Akbarzadeh Khorshidi M, Bose S, Watschke B, Mareena E, Lally C. Characterisation of human penile tissue properties using experimental testing combined with multi-target inverse finite element modelling. Acta Biomater 2024; 184:226-238. [PMID: 38945188 DOI: 10.1016/j.actbio.2024.06.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/05/2024] [Accepted: 06/24/2024] [Indexed: 07/02/2024]
Abstract
This paper presents an inverse finite element (FE) approach aimed at estimating multi-layered human penile tissues. The inverse FE approach integrates experimental force-displacement and boundary deformation data of penile tissues with a developed FE model and uses new experimental data on human penile tissue. The experimental study encompasses whole organ plate-compression tests and individual layer tensile and compression tests, providing comprehensive insights into the tissue's mechanical behaviour. The biomechanical characterisation of penile tissue is of crucial significance for understanding its mechanical behaviour under various physiological and pathological conditions. The FE model is constructed using the realistic geometry of the penile segment and appropriate constitutive models for each tissue layer to leverage the accuracy and consistency of the model. Through systematic variation of tissue parameters in the inverse FE algorithm, simulations achieve the best match with both force-displacement and deformed boundary results obtained from the whole organ plate-compression tests. Test results from individual tissue layers are also utilised to assess the estimated parameters. The proposed inverse FE approach allows for the estimation of penile tissue parameters with high precision and reliability, shedding light on the mechanical properties of this complex biological organ. This work has applications not only in urology but also for researchers in various disciplines of biomechanics. As a result, our study contributes to advancing the understanding of human penile tissue mechanics whilst the methodology could also be applied to a range of other soft biological tissues. STATEMENT OF SIGNIFICANCE: This research uses a multi-target inverse finite element (FE) approach for estimating the material parameters of human penile tissues. By integrating experimental data and a realistic FE model, this study achieves high-precision constitutive model parameter estimation, offering key insights into penile tissue mechanics under various loading conditions. The significance of this work lies in the use of this inverse FE approach for fresh-frozen human penile tissues, to identify the mechanical properties and constitutive models for both segregated tunica albuginea and corpus cavernosum as well as intact penile tissue segments. The study's scientific impact lies in its advancement of the understanding of human urological tissue mechanics, impacting researchers and clinicians alike.
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Affiliation(s)
- Majid Akbarzadeh Khorshidi
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland; Department of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland; Advanced Materials and BioEngineering Research Centre (AMBER), Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin 2, Ireland
| | - Shirsha Bose
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland; Department of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland; Advanced Materials and BioEngineering Research Centre (AMBER), Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin 2, Ireland
| | - Brian Watschke
- Urology, Boston Scientific Corp, Inc, Minnetonka, MN, USA
| | - Evania Mareena
- Urology, Boston Scientific Corp, Inc, Clonmel Co, Tipperary, Ireland
| | - Caitríona Lally
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland; Department of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin 2, Ireland; Advanced Materials and BioEngineering Research Centre (AMBER), Royal College of Surgeons in Ireland and Trinity College Dublin, Dublin 2, Ireland.
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15
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Peng C, He W, Luan J, Yuan T, Fu W, Shi Y, Wang S. Preliminary establishment and validation of the inversion method for growth and remodeling parameters of patient-specific abdominal aortic aneurysm. Biomech Model Mechanobiol 2024; 23:1137-1148. [PMID: 38548952 DOI: 10.1007/s10237-024-01828-4] [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: 10/31/2023] [Accepted: 02/09/2024] [Indexed: 08/24/2024]
Abstract
Traditional medical imaging and biomechanical studies have challenges in analyzing the long-term evolution process of abdominal aortic aneurysm (AAA). The homogenized constrained mixture theory (HCMT) allows for quantitative analysis of the changes in the multidimensional morphology and composition of AAA. However, the accuracy of HCMT still requires further clinical verification. This study aims to establish a patient-specific AAA growth model based on HCMT, simulate the long-term growth and remodeling (G&R) process of AAA, and validate the feasibility and accuracy of the method using two additional AAA cases with five follow-up datasets. The media and adventitia layers of AAA were modeled as mixtures composed of elastin, collagen fibers, and smooth muscle cells (SMCs). The strain energy function was used to describe the continuous deposition and degradation effect of the mixture during the AAA evolution. Multiple sets of growth parameters were applied to finite element simulations, and the simulation results were compared with the follow-up data for gradually selecting the optimal growth parameters. Two additional AAA patients with different growth rates were used for validating this method, the optimal growth parameters were obtained using the first two follow-up imaging data, and the growth model was applied to simulate the subsequent four time points. The differences between the simulated diameters and the follow-up diameters of AAA were compared to validate the accuracy of the mechanistic model. The growth parameters, especially the stress-mediated substance deposition gain factor, are highly related to the AAA G&R process. When setting the optimal growth parameters to simulate AAA growth, the proportion of simulation results within the distance of less than 0.5 mm from the baseline models is above 80%. For the validating cases, the mean difference rates between the simulated diameter and the real-world diameter are within 2.5%, which basically meets the clinical demand for quantitatively predicting the AAA growth in maximum diameters. This study simulated the growth process of AAA, and validated the accuracy of this mechanistic model. This method was proved to be used to predict the G&R process of AAA caused by dynamic changes in the mixtures of the AAA vessel wall during long-term, assisting accurately and quantitatively predicting the multidimensional morphological development and mixtures evolution process of AAA in the clinic.
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Affiliation(s)
- Chen Peng
- Artificial Intelligence Research Institute, Zhejiang Lab, Hangzhou, Zhejiang, China
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Wei He
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jingyang Luan
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Tong Yuan
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
- Institute of Vascular Surgery, Fudan University, Shanghai, China
- National Clinical Research Center for Interventional Medicine, Fudan University, Shanghai, China
| | - Yun Shi
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
- Institute of Vascular Surgery, Fudan University, Shanghai, China.
- National Clinical Research Center for Interventional Medicine, Fudan University, Shanghai, China.
| | - Shengzhang Wang
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China.
- Institute of Biomedical Engineering Technology, Academy for Engineering and Technology, Fudan University, Shanghai, China.
- Yiwu Research Institute, Fudan University, Yiwu, Zhejiang, China.
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16
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Todtenhaupt P, Kuipers TB, Dijkstra KL, Voortman LM, Franken LA, Spekman JA, Jonkman TH, Groene SG, Roest AA, Haak MC, Verweij EJT, van Pel M, Lopriore E, Heijmans BT, van der Meeren LE. Twisting the theory on the origin of human umbilical cord coiling featuring monozygotic twins. Life Sci Alliance 2024; 7:e202302543. [PMID: 38830769 PMCID: PMC11147950 DOI: 10.26508/lsa.202302543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
The human umbilical cord (hUC) is the lifeline that connects the fetus to the mother. Hypercoiling of the hUC is associated with pre- and perinatal morbidity and mortality. We investigated the origin of hUC hypercoiling using state-of-the-art imaging and omics approaches. Macroscopic inspection of the hUC revealed the helices to originate from the arteries rather than other components of the hUC. Digital reconstruction of the hUC arteries showed the dynamic alignment of two layers of muscle fibers in the tunica media aligning in opposing directions. We observed that genetically identical twins can be discordant for hUC coiling, excluding genetic, many environmental, and parental origins of hUC coiling. Comparing the transcriptomic and DNA methylation profile of the hUC arteries of four twin pairs with discordant cord coiling, we detected 28 differentially expressed genes, but no differentially methylated CpGs. These genes play a role in vascular development, cell-cell interaction, and axis formation and may account for the increased number of hUC helices. When combined, our results provide a novel framework to understand the origin of hUC helices in fetal development.
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Affiliation(s)
- Pia Todtenhaupt
- https://ror.org/05xvt9f17 Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Thomas B Kuipers
- https://ror.org/05xvt9f17 Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
- https://ror.org/05xvt9f17 Sequencing Analysis Support Core, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Kyra L Dijkstra
- https://ror.org/05xvt9f17 Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
| | - Lenard M Voortman
- https://ror.org/05xvt9f17 Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Laura A Franken
- https://ror.org/05xvt9f17 Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Jip A Spekman
- https://ror.org/05xvt9f17 Neonatology, Willem-Alexander Children's Hospital, Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Thomas H Jonkman
- https://ror.org/05xvt9f17 Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Sophie G Groene
- https://ror.org/05xvt9f17 Neonatology, Willem-Alexander Children's Hospital, Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Arno Aw Roest
- https://ror.org/05xvt9f17 Pediatric Cardiology, Willem-Alexander Children's Hospital, Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Monique C Haak
- https://ror.org/05xvt9f17 Department of Obstetrics, Division of Fetal Therapy, Leiden University Medical Center, Leiden, Netherlands
| | - EJoanne T Verweij
- https://ror.org/05xvt9f17 Department of Obstetrics, Division of Fetal Therapy, Leiden University Medical Center, Leiden, Netherlands
| | - Melissa van Pel
- NecstGen, Leiden, Netherlands
- https://ror.org/05xvt9f17 Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Enrico Lopriore
- https://ror.org/05xvt9f17 Neonatology, Willem-Alexander Children's Hospital, Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Bastiaan T Heijmans
- https://ror.org/05xvt9f17 Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Lotte E van der Meeren
- https://ror.org/05xvt9f17 Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
- Department of Pathology, Erasmus Medical Center, Rotterdam, Netherlands
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17
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Colebank MJ, Oomen PA, Witzenburg CM, Grosberg A, Beard DA, Husmeier D, Olufsen MS, Chesler NC. Guidelines for mechanistic modeling and analysis in cardiovascular research. Am J Physiol Heart Circ Physiol 2024; 327:H473-H503. [PMID: 38904851 DOI: 10.1152/ajpheart.00766.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 06/22/2024]
Abstract
Computational, or in silico, models are an effective, noninvasive tool for investigating cardiovascular function. These models can be used in the analysis of experimental and clinical data to identify possible mechanisms of (ab)normal cardiovascular physiology. Recent advances in computing power and data management have led to innovative and complex modeling frameworks that simulate cardiovascular function across multiple scales. While commonly used in multiple disciplines, there is a lack of concise guidelines for the implementation of computer models in cardiovascular research. In line with recent calls for more reproducible research, it is imperative that scientists adhere to credible practices when developing and applying computational models to their research. The goal of this manuscript is to provide a consensus document that identifies best practices for in silico computational modeling in cardiovascular research. These guidelines provide the necessary methods for mechanistic model development, model analysis, and formal model calibration using fundamentals from statistics. We outline rigorous practices for computational, mechanistic modeling in cardiovascular research and discuss its synergistic value to experimental and clinical data.
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Affiliation(s)
- Mitchel J Colebank
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
| | - Pim A Oomen
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
| | - Colleen M Witzenburg
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Anna Grosberg
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Dirk Husmeier
- School of Mathematics and Statistics, University of Glasgow, Glasgow, United Kingdom
| | - Mette S Olufsen
- Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States
| | - Naomi C Chesler
- Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States
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18
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Bantwal AS, Bhayadia AK, Meng H. Critical role of arterial constitutive model in predicting blood pressure from pulse wave velocity. Comput Biol Med 2024; 178:108730. [PMID: 38917535 DOI: 10.1016/j.compbiomed.2024.108730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/29/2024] [Accepted: 06/08/2024] [Indexed: 06/27/2024]
Abstract
BACKGROUND A promising approach to cuff-less, continuous blood pressure monitoring is to estimate blood pressure (BP) from Pulse Wave Velocity (PWV). However, most existing PWV-based methods rely on empirical BP-PWV relations and have large prediction errors, which may be caused by the implicit assumption of thin-walled, linear elastic arteries undergoing small deformations. Our objective is to understand the BP-PWV relationship in the absence of such limiting assumptions. METHOD We performed Fluid-Structure Interaction (FSI) simulations of the radial artery and the common carotid artery under physiological flow conditions. In these dynamic simulations, we employed two constitutive models for the arterial wall: the linear elastic model, implying a thin-walled linear elastic artery undergoing small deformations, and the Holzapfel-Gasser-Ogden (HGO) model, accounting for the nonlinear effects of collagen fibers and their orientations on the large arterial deformation. RESULTS Despite the changing BP, the linear elastic model predicts a constant PWV throughout a cardiac cycle, which is not physiological. The HGO model correctly predicts a positive BP-PWV correlation by capturing the nonlinear deformation of the artery, showing up to 50 % variations of PWV in a cardiac cycle. CONCLUSION Dynamic FSI simulations reveal that the BP-PWV relationship strongly depends on the arterial constitutive model, especially in the radial artery. To infer BP from PWV, one must account for the varying PWV, a consequence of the nonlinear arterial response due to collagen fibers. Future efforts should be directed towards robust measurement of time-varying PWV if it is to be used to predict BP.
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Affiliation(s)
| | - Amit Kumar Bhayadia
- Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY, 14260, USA.
| | - Hui Meng
- Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY, 14260, USA.
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19
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Yeerella RH, Cai S. Fracture mechanics modeling of aortic dissection. Biomech Model Mechanobiol 2024; 23:1377-1391. [PMID: 38658479 PMCID: PMC11341663 DOI: 10.1007/s10237-024-01845-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 03/29/2024] [Indexed: 04/26/2024]
Abstract
Aortic dissection, a critical cardiovascular condition with life-threatening implications, is distinguished by the development of a tear and its propagation within the aortic wall. A thorough understanding of the initiation and progression of these tears, or cracks, is essential for accurate diagnosis and effective treatment. This paper undertakes a fracture mechanics approach to delve into the mechanics of tear propagation in aortic dissection. Our objective is to elucidate the impact of geometric and material parameters, providing valuable insights into the determinants of this pivotal cardiovascular event. Through our investigation, we have gained an understanding of how various parameters influence the energy release rate for tear propagation in both longitudinal and circumferential directions, aligning our findings with clinical data.
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Affiliation(s)
- Ram Hemanth Yeerella
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA.
- Program in Materials Science and Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA.
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20
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Singh M, Roubertie F, Ozturk C, Borchiellini P, Rames A, Bonnemain J, Gollob SD, Wang SX, Naulin J, El Hamrani D, Dugot-Senant N, Gosselin I, Grenet C, L'Heureux N, Roche ET, Kawecki F. Hemodynamic evaluation of biomaterial-based surgery for Tetralogy of Fallot using a biorobotic heart, in silico, and ovine models. Sci Transl Med 2024; 16:eadk2936. [PMID: 38985852 DOI: 10.1126/scitranslmed.adk2936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 03/12/2024] [Accepted: 06/20/2024] [Indexed: 07/12/2024]
Abstract
Tetralogy of Fallot is a congenital heart disease affecting newborns and involves stenosis of the right ventricular outflow tract (RVOT). Surgical correction often widens the RVOT with a transannular enlargement patch, but this causes issues including pulmonary valve insufficiency and progressive right ventricle failure. A monocusp valve can prevent pulmonary regurgitation; however, valve failure resulting from factors including leaflet design, morphology, and immune response can occur, ultimately resulting in pulmonary insufficiency. A multimodal platform to quantitatively evaluate the effect of shape, size, and material on clinical outcomes could optimize monocusp design. This study introduces a benchtop soft biorobotic heart model, a computational fluid model of the RVOT, and a monocusp valve made from an entirely biological cell-assembled extracellular matrix (CAM) to tackle the multifaceted issue of monocusp failure. The hydrodynamic and mechanical performance of RVOT repair strategies was assessed in biorobotic and computational platforms. The monocusp valve design was validated in vivo in ovine models through echocardiography, cardiac magnetic resonance, and catheterization. These models supported assessment of surgical feasibility, handling, suturability, and hemodynamic and mechanical monocusp capabilities. The CAM-based monocusp offered a competent pulmonary valve with regurgitation of 4.6 ± 0.9% and a transvalvular pressure gradient of 4.3 ± 1.4 millimeters of mercury after 7 days of implantation in sheep. The biorobotic heart model, in silico analysis, and in vivo RVOT modeling allowed iteration in monocusp design not now feasible in a clinical environment and will support future surgical testing of biomaterials for complex congenital heart malformations.
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Affiliation(s)
- Manisha Singh
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - François Roubertie
- IHU Liryc, Electrophysiology and Heart Modeling Institute, F-33604 Pessac, France
- Congenital Heart Diseases Department, CHU de Bordeaux, F-33604 Pessac, France
| | - Caglar Ozturk
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Paul Borchiellini
- University of Bordeaux, INSERM, BioTis, U1026, F-33000 Bordeaux, France
| | - Adeline Rames
- University of Bordeaux, INSERM, BioTis, U1026, F-33000 Bordeaux, France
| | - Jean Bonnemain
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Department of Adult Intensive Care Medicine, Lausanne University Hospital and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Samuel Dutra Gollob
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sophie X Wang
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Department of Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Jérôme Naulin
- IHU Liryc, Electrophysiology and Heart Modeling Institute, F-33604 Pessac, France
| | - Dounia El Hamrani
- IHU Liryc, Electrophysiology and Heart Modeling Institute, F-33604 Pessac, France
| | - Nathalie Dugot-Senant
- Plateforme d'histopathologie, TBMcore INSERM US005-CNRS 3427, F-33000 Bordeaux, France
| | - Isalyne Gosselin
- Plateforme d'histopathologie, TBMcore INSERM US005-CNRS 3427, F-33000 Bordeaux, France
| | - Célia Grenet
- University of Bordeaux, INSERM, BioTis, U1026, F-33000 Bordeaux, France
| | - Nicolas L'Heureux
- University of Bordeaux, INSERM, BioTis, U1026, F-33000 Bordeaux, France
| | - Ellen T Roche
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Fabien Kawecki
- University of Bordeaux, INSERM, BioTis, U1026, F-33000 Bordeaux, France
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21
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Petřivý Z, Horný L, Tichý P. Traction-separation law parameters for the description of age-related changes in the delamination strength of the human descending thoracic aorta. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01871-1. [PMID: 38985231 DOI: 10.1007/s10237-024-01871-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/25/2024] [Indexed: 07/11/2024]
Abstract
Aortic dissection is a life-threatening disease that consists in the development of a tear in the wall of the aorta. The initial tear propagates as a discontinuity leading to separation within the aortic wall, which can result in the creation of a so-called false lumen. A fatal threat occurs if the rupture extends through the whole thickness of the aortic wall, as blood may then leak. It is generally accepted that the dissection, which can sometime extend along the entire length of the aorta, propagates via a delamination mechanism. The aim of the present paper is to provide experimentally validated parameters of a mathematical model for the description of the wall's cohesion. A model of the peeling experiment was built in Abaqus. The delamination interface was described by a piecewise linear traction-separation law. The bulk behavior of the aorta was assumed to be nonlinearly elastic, anisotropic, and incompressible. Our simulations resulted in estimates of the material parameters for the traction-separation law of the human descending thoracic aorta, which were obtained by minimizing the differences between the FEM predictions and the delamination force given by the regression of the peeling experiments. The results show that the stress at damage initiation, Tc, should be understood as an age-dependent quantity, and under the assumptions of our model this dependence can be expressed by linear regression as Tc = - 13.03·10-4·Age + 0.2485 if the crack front advances in the axial direction, and Tc = - 7.58·10-4·Age + 0.1897 if the crack front advances in the direction of the aortic circumference (Tc [MPa], Age [years]). Other model parameters were the stiffness K and the separation at failure, δf-δc (K = 0.5 MPa/mm, δf-δc = 0.1 mm). The material parameters provided by our study can be used in numerical simulations of the biomechanics of dissection propagation through the aorta especially when age-associated phenomena are studied.
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Affiliation(s)
- Zdeněk Petřivý
- Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 160 00, Prague, Czech Republic
| | - Lukáš Horný
- Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 160 00, Prague, Czech Republic.
| | - Petr Tichý
- Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 160 00, Prague, Czech Republic
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22
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Zamirpour S, Gulati A, Xuan Y, Leach JR, Saloner DA, Guccione JM, Boskovski MT, Ge L, Tseng EE. Temporal evolution of ascending aortic aneurysm wall stress predicts all-cause mortality. INTERDISCIPLINARY CARDIOVASCULAR AND THORACIC SURGERY 2024; 39:ivae116. [PMID: 38913870 PMCID: PMC11229433 DOI: 10.1093/icvts/ivae116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/29/2024] [Accepted: 06/18/2024] [Indexed: 06/26/2024]
Abstract
OBJECTIVES Diameter-based risk stratification for elective repair of ascending aortic aneurysm fails to prevent type A dissection in many patients. Aneurysm wall stresses may contribute to risk prediction; however, rates of wall stress change over time are poorly understood. Our objective was to examine aneurysm wall stress changes over 3-5 years and subsequent all-cause mortality. METHODS Male veterans with <5.5 cm ascending aortic aneurysms and computed tomography at baseline and 3- to 5-year follow-up underwent three-dimensional aneurysm model construction. Peak circumferential and longitudinal wall stresses at systole were calculated using finite element analysis. Temporal trends were assessed by mixed-effects modelling. Changes in aortic wall stresses, diameter and length over time were evaluated as predictors of subsequent 3-year all-cause mortality by Cox proportional hazards modelling. RESULTS Sixty-two male veterans were included in the study. Yearly changes in geometric and biomechanical measures were 0.12 mm/year (95% confidence interval, 0.04-0.20) for aortic diameter, 0.41 mm/year (0.12-0.71) for aortic length, 1.19 kPa/year -5.94 to 8.33) for peak circumferential stress, and 0.48 kPa/year (-3.89 to 4.84) for peak longitudinal stress. Yearly change in peak circumferential stress was significantly associated with hazard of death-hazard ratio for peak circumferential stress growth per 10 kPa/year, 1.27 (95% CI, 1.02-1.60; P = 0.037); hazard ratio for peak circumferential stress growth ≥ 32 kPa/year, 8.47 (95% CI, 2.42-30; P < 0.001). CONCLUSIONS In this population of nonsurgical aneurysm patients, large temporal changes in peak circumferential stress, but not aortic diameter or length, was associated with all-cause mortality. Biomechanical stress and stress changes over time may be beneficial as additional risk factors for elective surgery in small aneurysms.
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Affiliation(s)
- Siavash Zamirpour
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Arushi Gulati
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Yue Xuan
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Joseph R Leach
- Department of Radiology, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - David A Saloner
- Department of Radiology, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Julius M Guccione
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Marko T Boskovski
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Liang Ge
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
| | - Elaine E Tseng
- Department of Surgery, University of California San Francisco and San Francisco VA Healthcare System, San Francisco, CA, USA
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23
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Donmazov S, Saruhan EN, Pekkan K, Piskin S. Review of Machine Learning Techniques in Soft Tissue Biomechanics and Biomaterials. Cardiovasc Eng Technol 2024:10.1007/s13239-024-00737-y. [PMID: 38956008 DOI: 10.1007/s13239-024-00737-y] [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: 08/22/2023] [Accepted: 05/28/2024] [Indexed: 07/04/2024]
Abstract
BACKGROUND AND OBJECTIVE Advanced material models and material characterization of soft biological tissues play an essential role in pre-surgical planning for vascular surgeries and transcatheter interventions. Recent advances in heart valve engineering, medical device and patch design are built upon these models. Furthermore, understanding vascular growth and remodeling in native and tissue-engineered vascular biomaterials, as well as designing and testing drugs on soft tissue, are crucial aspects of predictive regenerative medicine. Traditional nonlinear optimization methods and finite element (FE) simulations have served as biomaterial characterization tools combined with soft tissue mechanics and tensile testing for decades. However, results obtained through nonlinear optimization methods are reliable only to a certain extent due to mathematical limitations, and FE simulations may require substantial computing time and resources, which might not be justified for patient-specific simulations. To a significant extent, machine learning (ML) techniques have gained increasing prominence in the field of soft tissue mechanics in recent years, offering notable advantages over conventional methods. This review article presents an in-depth examination of emerging ML algorithms utilized for estimating the mechanical characteristics of soft biological tissues and biomaterials. These algorithms are employed to analyze crucial properties such as stress-strain curves and pressure-volume loops. The focus of the review is on applications in cardiovascular engineering, and the fundamental mathematical basis of each approach is also discussed. METHODS The review effort employed two strategies. First, the recent studies of major research groups actively engaged in cardiovascular soft tissue mechanics are compiled, and research papers utilizing ML and deep learning (DL) techniques were included in our review. The second strategy involved a standard keyword search across major databases. This approach provided 11 relevant ML articles, meticulously selected from reputable sources including ScienceDirect, Springer, PubMed, and Google Scholar. The selection process involved using specific keywords such as "machine learning" or "deep learning" in conjunction with "soft biological tissues", "cardiovascular", "patient-specific," "strain energy", "vascular" or "biomaterials". Initially, a total of 25 articles were selected. However, 14 of these articles were excluded as they did not align with the criteria of focusing on biomaterials specifically employed for soft tissue repair and regeneration. As a result, the remaining 11 articles were categorized based on the ML techniques employed and the training data utilized. RESULTS ML techniques utilized for assessing the mechanical characteristics of soft biological tissues and biomaterials are broadly classified into two categories: standard ML algorithms and physics-informed ML algorithms. The standard ML models are then organized based on their tasks, being grouped into Regression and Classification subcategories. Within these categories, studies employ various supervised learning models, including support vector machines (SVMs), bagged decision trees (BDTs), artificial neural networks (ANNs) or deep neural networks (DNNs), and convolutional neural networks (CNNs). Additionally, the utilization of unsupervised learning approaches, such as autoencoders incorporating principal component analysis (PCA) and/or low-rank approximation (LRA), is based on the specific characteristics of the training data. The training data predominantly consists of three types: experimental mechanical data, including uniaxial or biaxial stress-strain data; synthetic mechanical data generated through non-linear fitting and/or FE simulations; and image data such as 3D second harmonic generation (SHG) images or computed tomography (CT) images. The evaluation of performance for physics-informed ML models primarily relies on the coefficient of determinationR 2 . In contrast, various metrics and error measures are utilized to assess the performance of standard ML models. Furthermore, our review includes an extensive examination of prevalent biomaterial models that can serve as physical laws for physics-informed ML models. CONCLUSION ML models offer an accurate, fast, and reliable approach for evaluating the mechanical characteristics of diseased soft tissue segments and selecting optimal biomaterials for time-critical soft tissue surgeries. Among the various ML models examined in this review, physics-informed neural network models exhibit the capability to forecast the mechanical response of soft biological tissues accurately, even with limited training samples. These models achieve highR 2 values ranging from 0.90 to 1.00. This is particularly significant considering the challenges associated with obtaining a large number of living tissue samples for experimental purposes, which can be time-consuming and impractical. Additionally, the review not only discusses the advantages identified in the current literature but also sheds light on the limitations and offers insights into future perspectives.
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Affiliation(s)
- Samir Donmazov
- Department of Mathematics, University of Kentucky, Lexington, KY, 40506, USA
| | - Eda Nur Saruhan
- Department of Computer Science and Engineering, Koc University, Sariyer, Istanbul, Turkey
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Sariyer, Istanbul, Turkey
| | - Senol Piskin
- Department of Mechanical Engineering, Faculty of Engineering and Natural Sciences, Istinye University, Vadi Kampusu, Sariyer, 34396, Istanbul, Turkey.
- Modeling, Simulation and Extended Reality Laboratory, Faculty of Engineering and Natural Sciences, Istinye University, Vadi Kampusu, Sariyer, 34396, Istanbul, Turkey.
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24
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Gueldner PH, Darvish CJ, Chickanosky IKM, Ahlgren EE, Fortunato R, Chung TK, Rajagopal K, Benjamin CC, Maiti S, Rajagopal KR, Vorp DA. Aortic tissue stiffness and tensile strength are correlated with density changes following proteolytic treatment. J Biomech 2024; 172:112226. [PMID: 39008917 DOI: 10.1016/j.jbiomech.2024.112226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 05/14/2024] [Accepted: 07/09/2024] [Indexed: 07/17/2024]
Abstract
INTRODUCTION Dissection or rupture of the aorta is accompanied by high mortality rates, and there is a pressing need for better prediction of these events for improved patient management and clinical outcomes. Biomechanically, these events represent a situation wherein the locally acting wall stress exceed the local tissue strength. Based on recent reports for polymers, we hypothesized that aortic tissue failure strength and stiffness are directly associated with tissue mass density. The objective of this work was to test this novel hypothesis for porcine thoracic aorta. METHODS Three tissue specimens from freshly harvested porcine thoracic aorta were treated with either collagenase or elastase to selectively degrade structural proteins in the tissue, or with phosphate buffer saline (control). The tissue mass and volume of each specimen were measured before and after treatment to allow for density calculation, then mechanically tested to failure under uniaxial extension. RESULTS Protease treatments resulted in statistically significant tissue density reduction (sham vs. collagenase p = 0.02 and sham vs elastase p = 0.003), which in turn was significantly and directly correlated with both ultimate tensile strength (sham vs. collagenase p = 0.02 and sham vs elastase p = 0.03) and tangent modulus (sham vs. collagenase p = 0.007 and sham vs elastase p = 0.03). CONCLUSIONS This work demonstrates for the first time that tissue stiffness and tensile strength are directly correlated with tissue density in proteolytically-treated aorta. These findings constitute an important step towards understanding aortic tissue failure mechanisms and could potentially be leveraged for non-invasive aortic strength assessment through density measurements, which could have implications to clinical care.
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Affiliation(s)
- Pete H Gueldner
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Cyrus J Darvish
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Emma E Ahlgren
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ronald Fortunato
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA
| | - Timothy K Chung
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Clinical and Translational Sciences Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Keshava Rajagopal
- Department of Cardiac Surgery, Jefferson University, Philadelphia, PA, USA
| | - Chandler C Benjamin
- Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Spandan Maiti
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kumbakonam R Rajagopal
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - David A Vorp
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA; Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, USA; Clinical and Translational Sciences Institute, University of Pittsburgh, Pittsburgh, PA, USA.
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25
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Wang X, Li K, Yuan Y, Zhang N, Zou Z, Wang Y, Yan S, Li X, Zhao P, Li Q. Nonlinear Elasticity of Blood Vessels and Vascular Grafts. ACS Biomater Sci Eng 2024; 10:3631-3654. [PMID: 38815169 DOI: 10.1021/acsbiomaterials.4c00326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
The transplantation of vascular grafts has emerged as a prevailing approach to address vascular disorders. However, the development of small-diameter vascular grafts is still in progress, as they serve in a more complicated mechanical environment than their counterparts with larger diameters. The biocompatibility and functional characteristics of small-diameter vascular grafts have been well developed; however, mismatch in mechanical properties between the vascular grafts and native arteries has not been accomplished, which might facilitate the long-term patency of small-diameter vascular grafts. From a point of view in mechanics, mimicking the nonlinear elastic mechanical behavior exhibited by natural blood vessels might be the state-of-the-art in designing vascular grafts. This review centers on elucidating the nonlinear elastic behavior of natural blood vessels and vascular grafts. The biological functionality and limitations associated with as-reported vascular grafts are meticulously reviewed and the future trajectory for fabricating biomimetic small-diameter grafts is discussed. This review might provide a different insight from the traditional design and fabrication of artificial vascular grafts.
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Affiliation(s)
- Xiaofeng Wang
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
| | - Kecheng Li
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Yuan Yuan
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Ning Zhang
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Zifan Zou
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Yun Wang
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Shujie Yan
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Xiaomeng Li
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Peng Zhao
- The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
| | - Qian Li
- School of Mechanics and Safety Engineering, National Center for International Research of Micro-nano Molding Technology, Zhengzhou University, Zhengzhou 450001, China
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26
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Donmazov S, Piskin S, Gölcez T, Kul D, Arnaz A, Pekkan K. Mechanical characterization and torsional buckling of pediatric cardiovascular materials. Biomech Model Mechanobiol 2024; 23:845-860. [PMID: 38361084 PMCID: PMC11101351 DOI: 10.1007/s10237-023-01809-z] [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: 07/17/2023] [Accepted: 12/22/2023] [Indexed: 02/17/2024]
Abstract
In complex cardiovascular surgical reconstructions, conduit materials that avoid possible large-scale structural deformations should be considered. A fundamental mode of mechanical complication is torsional buckling which occurs at the anastomosis site due to the mechanical instability, leading surgical conduit/patch surface deformation. The objective of this study is to investigate the torsional buckling behavior of commonly used materials and to develop a practical method for estimating the critical buckling rotation angle under physiological intramural vessel pressures. For this task, mechanical tests of four clinically approved materials, expanded polytetrafluoroethylene (ePTFE), Dacron, porcine and bovine pericardia, commonly used in pediatric cardiovascular surgeries, are conducted (n = 6). Torsional buckling initiation tests with n = 4 for the baseline case (L = 7.5 cm) and n = 3 for the validation of ePTFE (L = 15 cm) and Dacron (L = 15 cm and L = 25 cm) for each are also conducted at low venous pressures. A practical predictive formulation for the buckling potential is proposed using experimental observations and available theory. The relationship between the critical buckling rotation angle and the lumen pressure is determined by balancing the circumferential component of the compressive principal stress with the shear stress generated by the modified critical buckling torque, where the modified critical buckling torque depends linearly on the lumen pressure. While the proposed technique successfully predicted the critical rotation angle values lying within two standard deviations of the mean in the baseline case for all four materials at all lumen pressures, it could reliably predict the critical buckling rotation angles for ePTFE and Dacron samples of length 15 cm with maximum relative errors of 31% and 38%, respectively, in the validation phase. However, the validation of the performance of the technique demonstrated lower accuracy for Dacron samples of length 25 cm at higher pressure levels of 12 mmHg and 15 mmHg. Applicable to all surgical materials, this formulation enables surgeons to assess the torsional buckling potential of vascular conduits noninvasively. Bovine pericardium has been found to exhibit the highest stability, while Dacron (the lowest) and porcine pericardium have been identified as the least stable with the (unitless) torsional buckling resistance constants, 43,800, 12,300 and 14,000, respectively. There was no significant difference between ePTFE and Dacron, and between porcine and bovine pericardia. However, both porcine and bovine pericardia were found to be statistically different from ePTFE and Dacron individually (p < 0.0001). ePTFE exhibited highly nonlinear behavior across the entire strain range [0, 0.1] (or 10% elongation). The significant differences among the surgical materials reported here require special care in conduit construction and anastomosis design.
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Affiliation(s)
- Samir Donmazov
- Department of Mathematics, University of Kentucky, Kentucky, 40506, USA
| | - Senol Piskin
- Department of Mechanical Engineering, Istinye University, Istanbul, 34010, Turkey
| | - Tansu Gölcez
- Department of Bio-Medical Science and Engineering, Koc University, Istanbul, Turkey
| | - Demet Kul
- Department of Cellular and Molecular Medicine, Koc University, Istanbul, Turkey
| | - Ahmet Arnaz
- Department of Cardiovascular Surgery, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Sariyer, Istanbul, Turkey.
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27
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Balasubramanya A, Maes L, Rega F, Mazzi V, Morbiducci U, Famaey N, Degroote J, Segers P. Hemodynamics and wall shear metrics in a pulmonary autograft: Comparing a fluid-structure interaction and computational fluid dynamics approach. Comput Biol Med 2024; 176:108604. [PMID: 38761502 DOI: 10.1016/j.compbiomed.2024.108604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 05/02/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation. METHODS The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps. RESULTS Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p < 0.01) for TAWSS and (r > 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI. CONCLUSION FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA.
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Affiliation(s)
| | - Lauranne Maes
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Valentina Mazzi
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Nele Famaey
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Joris Degroote
- Department of Electromechanical Systems and Metal Engineering, Ghent University, Ghent, Belgium
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28
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Fortunato RN, Huckaby LV, Emerel LV, Schlosser V, Yang F, Phillippi JA, Vorp DA, Maiti S, Gleason TG. The predictive capability of aortic stiffness index for aortic dissection among dilated ascending aortas. J Thorac Cardiovasc Surg 2024; 167:2015-2024. [PMID: 36207164 PMCID: PMC10225159 DOI: 10.1016/j.jtcvs.2022.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 08/19/2022] [Accepted: 09/01/2022] [Indexed: 10/14/2022]
Abstract
OBJECTIVE We created a finite element model to predict the probability of dissection based on imaging-derived aortic stiffness and investigated the link between stiffness and wall tensile stress using our model. METHODS Transthoracic echocardiogram measurements were used to calculate aortic diameter change over the cardiac cycle. Aortic stiffness index was subsequently calculated based on diameter change and blood pressure. A series of logistic models were developed to predict the binary outcome of aortic dissection using 1 or more series of predictor parameters such as aortic stiffness index or patient characteristics. Finite element analysis was performed on a subset of diameter-matched patients exhibiting patient-specific material properties. RESULTS Transthoracic echocardiogram scans of patients with type A aortic dissection (n = 22) exhibited elevated baseline aortic stiffness index when compared with aneurysmal patients' scans with tricuspid aortic valve (n = 83, P < .001) and bicuspid aortic valve (n = 80, P < .001). Aortic stiffness index proved an excellent discriminator for a future dissection event (area under the curve, 0.9337, odds ratio, 2.896). From the parametric finite element study, we found a correlation between peak longitudinal wall tensile stress and stiffness index (ρ = .6268, P < .001, n = 28 pooled). CONCLUSIONS Noninvasive transthoracic echocardiogram-derived aortic stiffness measurements may serve as an impactful metric toward predicting aortic dissection or quantifying dissection risk. A correlation between longitudinal stress and stiffness establishes an evidence-based link between a noninvasive stiffness parameter and stress state of the aorta with clinically apparent dissection events.
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Affiliation(s)
- Ronald N Fortunato
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa
| | - Lauren V Huckaby
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pa
| | - Leonid V Emerel
- Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pa
| | - Virginia Schlosser
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa
| | - Fan Yang
- Department of Statistics, University of Pittsburgh School of Public Health, Pittsburgh, Pa
| | - Julie A Phillippi
- Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, Pittsburgh, Pa
| | - David A Vorp
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pa; Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, Pittsburgh, Pa; Department of Chemical and Petroleum Engineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; Asheville Heart, Asheville, NC
| | - Spandan Maiti
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; Department of Chemical and Petroleum Engineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa
| | - Thomas G Gleason
- Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, Pa; Asheville Heart, Asheville, NC.
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Li GY, Feng X, Yun SH. In Vivo Optical Coherence Elastography Unveils Spatial Variation of Human Corneal Stiffness. IEEE Trans Biomed Eng 2024; 71:1418-1429. [PMID: 38032780 PMCID: PMC11086014 DOI: 10.1109/tbme.2023.3338086] [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] [Indexed: 12/02/2023]
Abstract
OBJECTIVE The mechanical properties of corneal tissues play a crucial role in determining corneal shape and have significant implications in vision care. This study aimed to address the challenge of obtaining accurate in vivo data for the human cornea. METHODS We have developed a high-frequency optical coherence elastography (OCE) technique using shear-like antisymmetric (A0)-mode Lamb waves at frequencies above 10 kHz. RESULTS By incorporating an anisotropic, nonlinear constitutive model and utilizing the acoustoelastic theory, we gained quantitative insights into the influence of corneal tension on wave speeds and elastic moduli. Our study revealed significant spatial variations in the shear modulus of the corneal stroma on healthy subjects for the first time. Over an age span from 21 to 34 (N = 6), the central corneas exhibited a mean shear modulus of 87 kPa, while the corneal periphery showed a significant decrease to 44 kPa. The central cornea's shear modulus decreases with age with a slope of -19 +/- 8 kPa per decade, whereas the periphery showed non-significant age dependence. The limbus demonstrated an increased shear modulus exceeding 100 kPa. We obtained wave displacement profiles that are consistent with highly anisotropic corneal tissues. CONCLUSION Our approach enabled precise measurement of corneal tissue elastic moduli in situ with high precision (<7%) and high spatial resolution (<1 mm). Our results revealed significant stiffness variation from the central to peripheral corneas. SIGNIFICANCE The high-frequency OCE technique holds promise for biomechanical evaluation in clinical settings, providing valuable information for refractive surgeries, degenerative disorder diagnoses, and intraocular pressure assessments.
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Fischer J, Heidrová A, Hermanová M, Bednařík Z, Joukal M, Burša J. Structural parameters defining distribution of collagen fiber directions in human carotid arteries. J Mech Behav Biomed Mater 2024; 153:106494. [PMID: 38507995 DOI: 10.1016/j.jmbbm.2024.106494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/16/2024] [Accepted: 03/01/2024] [Indexed: 03/22/2024]
Abstract
Collagen fiber arrangement is decisive for constitutive description of anisotropic mechanical response of arterial wall. In this study, their orientation in human common carotid artery was investigated using polarized light microscopy and an automated algorithm giving more than 4·106 fiber angles per slice. In total 113 slices acquired from 18 arteries taken from 14 cadavers were used for fiber orientation in the circumferential-axial plane. All histograms were approximated with unimodal von Mises distribution to evaluate dominant direction of fibers and their concentration parameter. 10 specimens were analyzed also in circumferential-radial and axial-radial planes (2-4 slices per specimen in each plane); the portion of radially oriented fibers was found insignificant. In the circumferential-axial plane, most specimens showed a pronounced unimodal distribution with angle to circumferential direction μ = 0.7° ± 9.4° and concentration parameter b = 3.4 ± 1.9. Suitability of the unimodal fit was confirmed by high values of coefficient of determination (mean R2 = 0.97, median R2 = 0.99). Differences between media and adventitia layers were not found statistically significant. The results are directly applicable as structural parameters in the GOH constitutive model of arterial wall if the postulated two fiber families are unified into one with circumferential orientation.
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Affiliation(s)
- Jiří Fischer
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno, 616 69, Czech Republic.
| | - Aneta Heidrová
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno, 616 69, Czech Republic
| | - Markéta Hermanová
- 1st Department of Pathology, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Pekařská 664/53, 656 91, Brno, Czech Republic
| | - Zdeněk Bednařík
- 1st Department of Pathology, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Pekařská 664/53, 656 91, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Faculty of Medicine, Masaryk University, Kamenice 126/3, 625 00, Brno, Czech Republic
| | - Jiří Burša
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno, 616 69, Czech Republic
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31
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Szafron JM, Heng EE, Boyd J, Humphrey JD, Marsden AL. Hemodynamics and Wall Mechanics of Vascular Graft Failure. Arterioscler Thromb Vasc Biol 2024; 44:1065-1085. [PMID: 38572650 PMCID: PMC11043008 DOI: 10.1161/atvbaha.123.318239] [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: 09/04/2023] [Accepted: 03/12/2024] [Indexed: 04/05/2024]
Abstract
Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.
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Affiliation(s)
- Jason M Szafron
- Departments of Pediatrics (J.M.S., A.L.M.), Stanford University, CA
| | - Elbert E Heng
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jack Boyd
- Cardiothoracic Surgery (E.E.H., J.B.), Stanford University, CA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT (J.D.H.)
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Li Y, Yang Y, Shen M, Wang C, Chang L, Liu T, Wang Y. Investigation of the optimal cutting depth in small incision lenticule extraction based on a collagen fibril crimping constitutive model of the cornea. J Biomech 2024; 169:112145. [PMID: 38761745 DOI: 10.1016/j.jbiomech.2024.112145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 04/30/2024] [Accepted: 05/08/2024] [Indexed: 05/20/2024]
Abstract
To investigate the optimal cutting depth (Cap) in small incision lenticule extraction from the perspective of corneal biomechanics, a three-dimensional finite element model of the cornea was established using a stromal sub-regional material model to simulate small incision lenticule extraction. The displacement difference PΔ at the central point of the posterior corneal surface before and after lenticule extraction, as well as the von Mises stress at four points of different thicknesses in the center of the cornea, were analyzed using the finite element model considering the hyperelastic property and the difference in stiffness between the anterior and posterior of the cornea. The numerical curves of PΔ-Cap and von Mises Stress-Cap relations at different diopters show that the displacement difference PΔ has a smallest value at the same diopter. In this case, the von Mises stress at four points with different thicknesses in the center of the cornea was also minimal. Which means that the optimal cutting depth exsisting in the cornea. Moreover, PΔ-Cap curves for different depth of stromal stiffness boundaries show that the optimal cap thickness would change with the depth of the stromal stiffness boundary. These results are of guiding significance for accurately formulating small incision lenticule extraction surgery plans and contribute to the advancement of research on the biomechanical properties of the cornea.
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Affiliation(s)
- Yikuan Li
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
| | - Yaqing Yang
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
| | - Min Shen
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China.
| | - Congzheng Wang
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
| | - Le Chang
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin 300020, China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
| | - Taiwei Liu
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China; Department of Engineering Mechanics, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Yan Wang
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin 300020, China; Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China.
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Donahue CL, Westman CL, Faanes BL, Qureshi AM, Barocas VH, Aggarwal V. Finite element modeling with patient-specific geometry to assess clinical risks of percutaneous pulmonary valve implantation. Catheter Cardiovasc Interv 2024. [PMID: 38597297 DOI: 10.1002/ccd.31016] [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: 06/02/2023] [Revised: 03/10/2024] [Accepted: 03/19/2024] [Indexed: 04/11/2024]
Abstract
BACKGROUND Percutaneous pulmonary valve implantation (PPVI) is a non-surgical treatment for right ventricular outflow tract (RVOT) dysfunction. During PPVI, a stented valve, delivered via catheter, replaces the dysfunctional pulmonary valve. Stent oversizing allows valve anchoring within the RVOT, but overexpansion can intrude on the surrounding structures. Potentially dangerous outcomes include aortic valve insufficiency (AVI) from aortic root (AR) distortion and myocardial ischemia from coronary artery (CA) compression. Currently, risks are evaluated via balloon angioplasty/sizing before stent deployment. Patient-specific finite element (FE) analysis frameworks can improve pre-procedural risk assessment, but current methods require hundreds of hours of high-performance computation. METHODS We created a simplified method to simulate the procedure using patient-specific FE models for accurate, efficient pre-procedural PPVI (using balloon expandable valves) risk assessment. The methodology was tested by retrospectively evaluating the clinical outcome of 12 PPVI candidates. RESULTS Of 12 patients (median age 14.5 years) with dysfunctional RVOT, 7 had native RVOT and 5 had RV-PA conduits. Seven patients had undergone successful RVOT stent/valve placement, three had significant AVI on balloon testing, one had left CA compression, and one had both AVI and left CA compression. A model-calculated change of more than 20% in lumen diameter of the AR or coronary arteries correctly predicted aortic valve sufficiency and/or CA compression in all the patients. CONCLUSION Agreement between FE results and clinical outcomes is excellent. Additionally, these models run in 2-6 min on a desktop computer, demonstrating potential use of FE analysis for pre-procedural risk assessment of PPVI in a clinically relevant timeframe.
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Affiliation(s)
- Carly L Donahue
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, Minnesota, USA
| | - Claire L Westman
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, Minnesota, USA
| | - Brittany L Faanes
- Division of Pediatric Cardiology, Department of Pediatrics, University of Minnesota Masonic Children's Hospital, Minneapolis, Minnesota, USA
| | - Athar M Qureshi
- Department of Pediatrics, The Lillei Frank Abercombie Section of Pediatric Cardiology, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
| | - Victor H Barocas
- Department of Biomedical Engineering, University of Minnesota, Twin Cities, Minnesota, USA
| | - Varun Aggarwal
- Division of Pediatric Cardiology, Department of Pediatrics, University of Minnesota Masonic Children's Hospital, Minneapolis, Minnesota, USA
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Wang X, Wang S, Holland MA. Axonal tension contributes to consistent fold placement. SOFT MATTER 2024; 20:3053-3065. [PMID: 38506323 DOI: 10.1039/d4sm00129j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Cortical folding is a critical process during brain development, resulting in morphologies that are both consistent and distinct between individuals and species. While earlier studies have highlighted important aspects of cortical folding, most existing computational models, based on the differential growth theory, fall short of explaining why folds tend to appear in particular locations. The axon tension hypothesis may provide insight into this conundrum; however, there has been significant controversy about a potential role of axonal tension during the gyrification. The common opinion in the field is that axonal tension is inadequate to drive gyrification, but we currently run the risk of discarding this hypothesis without comprehensively studying the role of axonal tension. Here we propose a novel bi-layered finite element model incorporating the two theories, including characteristic axonal tension in the subcortex and differential cortical growth. We show that axon tension can serve as a perturbation sufficient to trigger buckling in simulations; similarly to other types of perturbations, the natural stability behavior of the system tends to determine some characteristics of the folding morphology (e.g. the wavelength) while the perturbation determines the location of folds. Certain geometries, however, can interact or compete with the natural stability of the system to change the wavelength. When multiple perturbations are present, they similarly compete with each other. We found that an axon bundle of reasonable size will overpower up to a 5% thickness perturbation (typical in the literature) and determine fold placement. Finally, when multiple axon tracts are present, even a slight difference in axon stiffness, representing the heterogeneity of axonal connections, is enough to significantly change the folding pattern. While the simulations presented here are a very simple representation of white matter connectivity, our findings point to urgent future research on the role of axon connectivity in cortical folding.
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Affiliation(s)
- Xincheng Wang
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Shuolun Wang
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Maria A Holland
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
- Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
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Pukaluk A, Sommer G, Holzapfel GA. Multimodal experimental studies of the passive mechanical behavior of human aortas: Current approaches and future directions. Acta Biomater 2024; 178:1-12. [PMID: 38401775 DOI: 10.1016/j.actbio.2024.02.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/26/2024]
Abstract
Cardiovascular diseases are the leading cause of death worldwide and include, among others, critical conditions of the aortic wall. Importantly, such critical conditions require effective diagnosis and treatment, which are not yet accurate enough. However, they could be significantly strengthened with predictive material models of the aortic wall. In particular, such predictive models could support surgical decisions, preoperative planning, and estimation of postoperative tissue remodeling. However, developing a predictive model requires experimental data showing both structural parameters and mechanical behavior. Such experimental data can be obtained using multimodal experiments. This review therefore discusses the current approaches to multimodal experiments. Importantly, the strength of the aortic wall is determined primarily by its passive components, i.e., mainly collagen, elastin, and proteoglycans. Therefore, this review focuses on multimodal experiments that relate the passive mechanical behavior of the human aortic wall to the structure and organization of its passive components. In particular, the multimodal experiments are classified according to the expected results. Multiple examples are provided for each experimental class and summarized with highlighted advantages and disadvantages of the method. Finally, future directions of multimodal experiments are envisioned and evaluated. STATEMENT OF SIGNIFICANCE: Multimodal experiments are innovative approaches that have gained interest very quickly, but also recently. This review presents therefore a first clear summary of groundbreaking research in the field of multimodal experiments. The benefits and limitations of various types of multimodal experiments are thoroughly discussed, and a comprehensive overview of possible results is provided. Although this review focuses on multimodal experiments performed on human aortic tissues, the methods used and described are not limited to human aortic tissues but can be extended to other soft materials.
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Affiliation(s)
- Anna Pukaluk
- Institute of Biomechanics, Graz University of Technology, Austria
| | - Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, Austria
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Austria; Department of Structural Engineering (NTNU), Trondheim, Norway.
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36
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Qin T, Mao W, Caballero A, Kamioka N, Lerakis S, Lain S, Elefteriades J, Liang L, Sun W. Patient-specific analysis of bicuspid aortic valve hemodynamics using a fully coupled fluid-structure interaction model. Comput Biol Med 2024; 172:108191. [PMID: 38457932 DOI: 10.1016/j.compbiomed.2024.108191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/10/2024] [Accepted: 02/18/2024] [Indexed: 03/10/2024]
Abstract
Bicuspid aortic valve (BAV), the most common congenital heart disease, is prone to develop significant valvular dysfunction and aortic wall abnormalities such as ascending aortic aneurysm. Growing evidence has suggested that abnormal BAV hemodynamics could contribute to disease progression. In order to investigate BAV hemodynamics, we performed 3D patient-specific fluid-structure interaction (FSI) simulations with fully coupled blood flow dynamics and valve motion throughout the cardiac cycle. Results showed that the hemodynamics during systole can be characterized by a systolic jet and two counter-rotating recirculation vortices. At peak systole, the jet was usually eccentric, with asymmetric recirculation vortices and helical flow motion in the ascending aorta. The flow structure at peak systole was quantified using the vorticity, flow rate reversal ratio and local normalized helicity (LNH) at four locations from the aortic root to the ascending aorta. The systolic jet was evaluated with the peak velocity, normalized flow displacement, and jet angle. It was found that peak velocity and normalized flow displacement (rather than jet angle) gave a strong correlation with the vorticity and LNH in the ascending aorta, which suggests that these two metrics could be used for clinical noninvasive evaluation of abnormal blood flow patterns in BAV patients.
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Affiliation(s)
- Tongran Qin
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; Sutra Medical Inc, Lake Forest, CA, USA
| | - Wenbin Mao
- Mechanical Engineering, University of South Florida, FL, USA
| | - Andrés Caballero
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; PAI+ Research Group, Mechanical Engineering Department, Universidad Autónoma de Occidente, Cali, Colombia
| | | | - Stamatios Lerakis
- Emory University, School of Medicine, Atlanta, GA, USA; Division of Cardiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Santiago Lain
- PAI+ Research Group, Mechanical Engineering Department, Universidad Autónoma de Occidente, Cali, Colombia
| | - John Elefteriades
- Aortic Institute, School of Medicine, Yale University, New Haven, CT, USA
| | - Liang Liang
- Department of Computer Science, University of Miami, Coral Gables, FL, USA
| | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; Sutra Medical Inc, Lake Forest, CA, USA.
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Raviol J, Plet G, Langlois JB, Si-Mohamed S, Magoariec H, Pailler-Mattei C. In vivo mechanical characterization of arterial wall using an inverse analysis procedure: application on an animal model of intracranial aneurysm. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231936. [PMID: 38633347 PMCID: PMC11022001 DOI: 10.1098/rsos.231936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/19/2024] [Accepted: 02/24/2024] [Indexed: 04/19/2024]
Abstract
Intracranial aneurysm is a pathology related to the deterioration of the arterial wall. This work is an essential part of a large-scale project aimed at providing clinicians with a non-invasive patient-specific decision support tool to facilitate the rupture risk assessment. It will lean on the link between the aneurysm shape clinically observed and a database derived from the in vivo mechanical characterization of aneurysms. To supply this database, a deformation device prototype of the arterial wall was developed. Its use coupled with medical imaging (spectral photon-counting computed tomography providing a spatial resolution down to 250 μm) is used to determine the in vivo mechanical properties of the wall based on the inverse analysis of the quantification of the wall deformation observed experimentally. This study presents the in vivo application of this original procedure to an animal model of aneurysm. The mechanical properties of the aneurysm wall identified were consistent with the literature, and the errors between the numerical and experimental results were less than 10%. Based on these parameters, this study allows the assessment of the aneurysm stress state for a known solicitation and points towards the definition of a rupture criterion.
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Affiliation(s)
- J. Raviol
- Ecole Centrale de Lyon, CNRS, ENTPE, LTDS, UMR 5513, Écully69130, France
| | - G. Plet
- Ecole Centrale de Lyon, CNRS, ENTPE, LTDS, UMR 5513, Écully69130, France
| | | | - S. Si-Mohamed
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F69621, Villeurbanne69100, France
- Département de Radiologie, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron69677, France
| | - H. Magoariec
- Ecole Centrale de Lyon, CNRS, ENTPE, LTDS, UMR 5513, Écully69130, France
| | - C. Pailler-Mattei
- Ecole Centrale de Lyon, CNRS, ENTPE, LTDS, UMR 5513, Écully69130, France
- Université de Lyon, Université Claude Bernard Lyon 1, ISPB-Faculté de Pharmacie, Lyon69008, France
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Suárez S, López-Campos JA, Fernández JR, Segade A. Nonlocal damage evaluation of a sigmoid-based damage model for fibrous biological soft tissues. Biomech Model Mechanobiol 2024; 23:655-674. [PMID: 38158483 DOI: 10.1007/s10237-023-01798-z] [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: 09/26/2023] [Accepted: 11/22/2023] [Indexed: 01/03/2024]
Abstract
The comprehension and modeling of the mechanical behavior of soft biological tissues are essential due to their clinical applications. This knowledge is essential for predicting tissue responses accurately and enhancing our ability to compute the behavior of biological structures and bio-prosthetic devices under specific loading conditions. The current research is centered on modeling the initiation and progression of soft tissues damage, which typically exhibit intricate anisotropic and nonlinear elastic characteristics. For this purpose, the following study presents a comparative analysis of the computational performance of two distinct damage modeling techniques. The first technique employs a well-established damage model, based on a piece-wise exponential damage function as proposed by Calvo et al. (Int J Numer Methods Eng 69:2036-2057, 2007. https://doi.org/10.1002/nme.1825 ). The second approach adopts a sigmoid function, as proposed by López-Campos et al. (Comput Methods Biomech Biomed Eng 23(6):213-223. https://doi.org/10.1080/10255842.2019.1710742 ). The aim of this study is to verify the validity of the López-Campos sigmoid-based damage model to be used in finite element simulation, the implementation of which is unknown. For this proposal, both models were implemented within a commercial Finite Element software package, and their responses to local and non-local damage algorithms were assessed in depth through two standard benchmark tests: a plate with a hole and a ball burst. The results of this study indicate that, for a wide range of cases, such as in-plane stresses, out-plane stresses, stress concentration and contact, all over large displacement conditions, the López-Campos damage model shows a good response to non-local algorithms achieving mesh independence and convergence in all these cases. The results obtained are in line with those obtained for the Calvo's damage model, showing, in addition, larger deformations under in-plane stress and stress concentration conditions and a lower number of iterations under out-plane stress and contact conditions. Consequently, the López-Campos' damage model emerges as a valuable and useful tool in the field of mechanical damage research in biological systems.
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Affiliation(s)
- Sofía Suárez
- CINTECX, Department of Mechanical Engineering, Universidade de Vigo, Campus As Lagoas, Marcosende, 36310, Vigo, Pontevedra, Spain.
- Design and Numerical Simulation Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Hospital Álvaro Cunqueiro, Carretera Clara Campoamor 341, Tecnical Building 2º Floor, 36312, Vigo, Pontevedra, Spain.
| | - Jose A López-Campos
- CINTECX, Department of Mechanical Engineering, Universidade de Vigo, Campus As Lagoas, Marcosende, 36310, Vigo, Pontevedra, Spain
- Design and Numerical Simulation Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Hospital Álvaro Cunqueiro, Carretera Clara Campoamor 341, Tecnical Building 2º Floor, 36312, Vigo, Pontevedra, Spain
| | - Jose R Fernández
- Design and Numerical Simulation Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Hospital Álvaro Cunqueiro, Carretera Clara Campoamor 341, Tecnical Building 2º Floor, 36312, Vigo, Pontevedra, Spain
- Department of Applied Mathematics I, Industrial Engineering School, Universidade de Vigo, Campus As Lagoas, Marcosende, 36310, Vigo, Pontevedra, Spain
| | - Abraham Segade
- CINTECX, Department of Mechanical Engineering, Universidade de Vigo, Campus As Lagoas, Marcosende, 36310, Vigo, Pontevedra, Spain
- Design and Numerical Simulation Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Hospital Álvaro Cunqueiro, Carretera Clara Campoamor 341, Tecnical Building 2º Floor, 36312, Vigo, Pontevedra, Spain
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Zamirpour S, Xuan Y, Wang Z, Gomez A, Leach JR, Mitsouras D, Saloner DA, Guccione JM, Ge L, Tseng EE. Height and body surface area versus wall stress for stratification of mid-term outcomes in ascending aortic aneurysm. IJC HEART & VASCULATURE 2024; 51:101375. [PMID: 38435381 PMCID: PMC10909604 DOI: 10.1016/j.ijcha.2024.101375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/13/2024] [Accepted: 02/23/2024] [Indexed: 03/05/2024]
Abstract
Objectives Current diameter-based guidelines for ascending thoracic aortic aneurysms (aTAA) do not consistently predict risk of dissection/rupture. ATAA wall stresses may enhance risk stratification independent of diameter. The relation of wall stresses and diameter indexed to height and body surface area (BSA) is unknown. Our objective was to compare aTAA wall stresses with indexed diameters in relation to all-cause mortality at 3.75 years follow-up. Methods Finite element analyses were performed in a veteran population with aortas ≥ 4.0 cm. Three-dimensional geometries were reconstructed from computed tomography with models accounting for pre-stress geometries. A fiber-embedded hyperelastic material model was applied to obtain wall stress distributions under systolic pressure. Peak wall stresses were compared across guideline thresholds for diameter/BSA and diameter/height. Hazard ratios for all-cause mortality and surgical aneurysm repair were estimated using cause-specific Cox proportional hazards models. Results Of 253 veterans, 54 (21 %) had aneurysm repair at 3.75 years. Indexed diameter alone would have prompted repair at baseline in 17/253 (6.7 %) patients, including only 4/230 (1.7 %) with diameter < 5.5 cm. Peak wall stresses did not significantly differ across guideline thresholds for diameter/BSA (circumferential: p = 0.15; longitudinal: p = 0.18), but did differ for diameter/height (circumferential: p = 0.003; longitudinal: p = 0.048). All-cause mortality was independently associated with peak longitudinal stresses (p = 0.04). Peak longitudinal stresses were best predicted by diameter (c-statistic = 0.66), followed by diameter/height (c-statistic = 0.59), and diameter/BSA (c-statistic = 0.55). Conclusions Diameter/height improved stratification of peak wall stresses compared to diameter/BSA. Peak longitudinal stresses predicted all-cause mortality independent of age and indexed diameter and may aid risk stratification for aTAA adverse events.
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Affiliation(s)
- Siavash Zamirpour
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
- School of Medicine, University of California, San Francisco, USA
| | - Yue Xuan
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Zhongjie Wang
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Axel Gomez
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Joseph R. Leach
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Dimitrios Mitsouras
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - David A. Saloner
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Julius M. Guccione
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Liang Ge
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
| | - Elaine E. Tseng
- Department of Surgery, Division of Adult Cardiothoracic Surgery, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, USA
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Ahuja A, Guo X, Noblet JN, Krieger JF, Roeder B, Haulon S, Chambers S, Kassab G. Dissection flap fenestration can reduce re-apposition force of the false lumen in type-B aortic dissection: a computational and bench study. Front Bioeng Biotechnol 2024; 12:1326190. [PMID: 38605989 PMCID: PMC11007646 DOI: 10.3389/fbioe.2024.1326190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/14/2024] [Indexed: 04/13/2024] Open
Abstract
Thoracic endovascular aortic repair (TEVAR) has been widely adopted as a standard for treating complicated acute and high-risk uncomplicated Stanford Type-B aortic dissections. The treatment redirects the blood flow towards the true lumen by covering the proximal dissection tear which promotes sealing of the false lumen. Despite advances in TEVAR, over 30% of Type-B dissection patients require additional interventions. This is primarily due to the presence of a persistent patent false lumen post-TEVAR that could potentially enlarge over time. We propose a novel technique, called slit fenestration pattern creation, which reduces the forces for re-apposition of the dissection flap (i.e., increase the compliance of the flap). We compute the optimal slit fenestration design using a virtual design of experiment (DOE) and demonstrate its effectiveness in reducing the re-apposition forces through computational simulations and benchtop experiments using porcine aortas. The findings suggest this potential therapy can drastically reduce the radial loading required to re-appose a dissected flap against the aortic wall to ensure reconstitution of the aortic wall (remodeling).
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Affiliation(s)
- Aashish Ahuja
- California Medical Innovations Institute, San Diego, CA, United States
| | - Xiaomei Guo
- California Medical Innovations Institute, San Diego, CA, United States
| | | | | | | | - Stéphan Haulon
- Chirurgie Vasculaire—Centre de l’Aorte, Hôpital Marie Lannelongue, Université Paris Saclay, Paris, France
| | | | - Ghassan Kassab
- California Medical Innovations Institute, San Diego, CA, United States
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Lin AC, Pirrung F, Niestrawska JA, Ondruschka B, Pinter G, Henyš P, Hammer N. Shape or size matters? Towards standard reporting of tensile testing parameters for human soft tissues: systematic review and finite element analysis. Front Bioeng Biotechnol 2024; 12:1368383. [PMID: 38600944 PMCID: PMC11005100 DOI: 10.3389/fbioe.2024.1368383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/14/2024] [Indexed: 04/12/2024] Open
Abstract
Material properties of soft-tissue samples are often derived through uniaxial tensile testing. For engineering materials, testing parameters (e.g., sample geometries and clamping conditions) are described by international standards; for biological tissues, such standards do not exist. To investigate what testing parameters have been reported for tensile testing of human soft-tissue samples, a systematic review of the literature was performed using PRISMA guidelines. Soft tissues are described as anisotropic and/or hyperelastic. Thus, we explored how the retrieved parameters compared against standards for engineering materials of similar characteristics. All research articles published in English, with an Abstract, and before 1 January 2023 were retrieved from databases of PubMed, Web of Science, and BASE. After screening of articles based on search terms and exclusion criteria, a total 1,096 articles were assessed for eligibility, from which 361 studies were retrieved and included in this review. We found that a non-tapered shape is most common (209 of 361), followed by a tapered sample shape (92 of 361). However, clamping conditions varied and were underreported (156 of 361). As a preliminary attempt to explore how the retrieved parameters might influence the stress distribution under tensile loading, a pilot study was performed using finite element analysis (FEA) and constitutive modeling for a clamped sample of little or no fiber dispersion. The preliminary FE simulation results might suggest the hypothesis that different sample geometries could have a profound influence on the stress-distribution under tensile loading. However, no conclusions can be drawn from these simulations, and future studies should involve exploring different sample geometries under different computational models and sample parameters (such as fiber dispersion and clamping effects). Taken together, reporting and choice of testing parameters remain as challenges, and as such, recommendations towards standard reporting of uniaxial tensile testing parameters for human soft tissues are proposed.
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Affiliation(s)
- Alvin C. Lin
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Salzburg, Austria
| | - Felix Pirrung
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Justyna A. Niestrawska
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Benjamin Ondruschka
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerald Pinter
- Institute of Materials Science and Testing of Polymers, Montanuniversität Leoben, Leoben, Austria
| | - Petr Henyš
- Institute of New Technologies and Applied Informatics, Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Liberec, Czechia
| | - Niels Hammer
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany
- Fraunhofer Institute for Forming Tools, Division of Biomechatronics, Dresden, Germany
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Sauer TJ, Buckler AJ, Abadi E, Daubert M, Douglas PS, Samei E, Segars WP. Development of physiologically-informed computational coronary artery plaques for use in virtual imaging trials. Med Phys 2024; 51:1583-1596. [PMID: 38306457 DOI: 10.1002/mp.16959] [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: 06/01/2023] [Revised: 10/30/2023] [Accepted: 01/16/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND As a leading cause of death, worldwide, cardiovascular disease is of great clinical importance. Among cardiovascular diseases, coronary artery disease (CAD) is a key contributor, and it is the attributed cause of death for 10% of all deaths annually. The prevalence of CAD is commensurate with the rise in new medical imaging technologies intended to aid in its diagnosis and treatment. The necessary clinical trials required to validate and optimize these technologies require a large cohort of carefully controlled patients, considerable time to complete, and can be prohibitively expensive. A safer, faster, less expensive alternative is using virtual imaging trials (VITs), utilizing virtual patients or phantoms combined with accurate computer models of imaging devices. PURPOSE In this work, we develop realistic, physiologically-informed models for coronary plaques for application in cardiac imaging VITs. METHODS Histology images of plaques at micron-level resolution were used to train a deep convolutional generative adversarial network (DC-GAN) to create a library of anatomically variable plaque models with clinical anatomical realism. The stability of each plaque was evaluated by finite element analysis (FEA) in which plaque components and vessels were meshed as volumes, modeled as specialized tissues, and subjected to the range of normal coronary blood pressures. To demonstrate the utility of the plaque models, we combined them with the whole-body XCAT computational phantom to perform initial simulations comparing standard energy-integrating detector (EID) CT with photon-counting detector (PCD) CT. RESULTS Our results show the network is capable of generating realistic, anatomically variable plaques. Our simulation results provide an initial demonstration of the utility of the generated plaque models as targets to compare different imaging devices. CONCLUSIONS Vast, realistic, and variable CAD pathologies can be generated to incorporate into computational phantoms for VITs. There they can serve as a known truth from which to optimize and evaluate cardiac imaging technologies quantitatively.
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Affiliation(s)
- Thomas J Sauer
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, the Duke University Medical Center, Durham, North Carolina, USA
| | | | - Ehsan Abadi
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, the Duke University Medical Center, Durham, North Carolina, USA
| | - Melissa Daubert
- Duke Department of Medicine, the Duke University Medical Center, Durham, North Carolina, USA
| | - Pamela S Douglas
- Duke Department of Medicine, the Duke University Medical Center, Durham, North Carolina, USA
| | - Ehsan Samei
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, the Duke University Medical Center, Durham, North Carolina, USA
| | - William P Segars
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, the Duke University Medical Center, Durham, North Carolina, USA
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Gheysen L, Maes L, Caenen A, Segers P, Peirlinck M, Famaey N. Uncertainty quantification of the wall thickness and stiffness in an idealized dissected aorta. J Mech Behav Biomed Mater 2024; 151:106370. [PMID: 38224645 DOI: 10.1016/j.jmbbm.2024.106370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 12/21/2023] [Accepted: 01/01/2024] [Indexed: 01/17/2024]
Abstract
Personalized treatment informed by computational models has the potential to markedly improve the outcome for patients with a type B aortic dissection. However, existing computational models of dissected walls significantly simplify the characteristic false lumen, tears and/or material behavior. Moreover, the patient-specific wall thickness and stiffness cannot be accurately captured non-invasively in clinical practice, which inevitably leads to assumptions in these wall models. It is important to evaluate the impact of the corresponding uncertainty on the predicted wall deformations and stress, which are both key outcome indicators for treatment optimization. Therefore, a physiology-inspired finite element framework was proposed to model the wall deformation and stress of a type B aortic dissection at diastolic and systolic pressure. Based on this framework, 300 finite element analyses, sampled with a Latin hypercube, were performed to assess the global uncertainty, introduced by 4 uncertain wall thickness and stiffness input parameters, on 4 displacement and stress output parameters. The specific impact of each input parameter was estimated using Gaussian process regression, as surrogate model of the finite element framework, and a δ moment-independent analysis. The global uncertainty analysis indicated minor differences between the uncertainty at diastolic and systolic pressure. For all output parameters, the 4th quartile contained the major fraction of the uncertainty. The parameter-specific uncertainty analysis elucidated that the material stiffness and relative thickness of the dissected membrane were the respective main determinants of the wall deformation and stress. The uncertainty analysis provides insight into the effect of uncertain wall thickness and stiffness parameters on the predicted deformation and stress. Moreover, it emphasizes the need for probabilistic rather than deterministic predictions for clinical decision making in aortic dissections.
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Affiliation(s)
- Lise Gheysen
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium.
| | - Lauranne Maes
- Biomechanics Section, Mechanical Engineering, KU Leuven, Belgium
| | - Annette Caenen
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium; Cardiovascular Imaging and Dynamics, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Patrick Segers
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium
| | - Mathias Peirlinck
- Department of BioMechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, the Netherlands
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering, KU Leuven, Belgium
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Kailash KA, Hawes JZ, Cocciolone AJ, Bersi MR, Mecham RP, Wagenseil JE. Constitutive Modeling of Mouse Arteries Suggests Changes in Directional Coupling and Extracellular Matrix Remodeling That Depend on Artery Type, Age, Sex, and Elastin Amounts. J Biomech Eng 2024; 146:051001. [PMID: 37646627 DOI: 10.1115/1.4063272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 08/21/2023] [Indexed: 09/01/2023]
Abstract
Arterial stiffening occurs during natural aging, is associated with an increased risk of adverse cardiovascular events, and can follow different timelines in males and females. One mechanism of arterial stiffening includes remodeling of the extracellular matrix (ECM), which alters the wall material properties. We used elastin haploinsufficient (Eln+/-) and wildtype (Eln+/+) mice to investigate how material properties of two different arteries (ascending aorta and carotid artery) change with age, sex, and ECM composition. We used a constitutive model by Dong and Sun that is based on the Holzapfel-Gasser-Ogden (HGO) type, but does not require a discrete number of fibrous ECM families and allows varied deformation coupling. We find that the amount of deformation coupling for the best fit model depends on the artery type. We also find that remodeling to maintain homeostatic (i.e., young, wildtype) values of biomechanical parameters with age, sex, and ECM composition depends on the artery type, with ascending aorta being more adaptable than carotid artery. Fitted material constants indicate sex-dependent remodeling that may be important for determining the time course of arterial stiffening in males and females. We correlated fitted material constants with ECM composition measured by biochemical (ascending aorta) or histological (carotid artery) methods. We show significant correlations between ECM composition and material parameters for the mean values for each group, with biochemical measurements correlating more strongly than histological measurements. Understanding how arterial stiffening depends on age, sex, ECM composition, and artery type may help design effective, personalized clinical treatment strategies.
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Affiliation(s)
- Keshav A Kailash
- Biomedical Engineering, Washington University, St. Louis, MO 63130
| | - Jie Z Hawes
- Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Austin J Cocciolone
- Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Matthew R Bersi
- Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130
| | - Robert P Mecham
- Cell Biology and Physiology, Washington University, St. Louis, MO 63130
| | - Jessica E Wagenseil
- Mechanical Engineering and Materials Science, Washington University, One Brookings Dr., MSC 1185-208-125, St. Louis, MO 63130
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Jyoti Mech D, Suhail Rizvi M. Micromechanics of fibrous scaffolds and their stiffness sensing by cells. Biomed Mater 2024; 19:025035. [PMID: 38290154 DOI: 10.1088/1748-605x/ad2409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/30/2024] [Indexed: 02/01/2024]
Abstract
Mechanical properties of the tissue engineering scaffolds are known to play a crucial role in cell response. Therefore, an understanding of the cell-scaffold interactions is of high importance. Here, we have utilized discrete fiber network model to quantitatively study the micromechanics of fibrous scaffolds with different fiber arrangements and cross-linking densities. We observe that localized forces on the scaffold result in its anisotropic deformation even for isotropic fiber arrangements. We also see an exponential decay of the displacement field with distance from the location of applied force. This nature of the decay allows us to estimate the characteristic length for force transmission in fibrous scaffolds. Furthermore, we also looked at the stiffness sensing of fibrous scaffolds by individual cells and its dependence on the cellular sensing mechanism. For this, we considered two conditions- stress-controlled, and strain-controlled application of forces by a cell. With fixed strain, we find that the stiffness sensed by a cell is proportional to the scaffold's 'macroscopic' elastic modulus. However, under fixed stress application by the cell, the stiffness sensed by the cell also depends on the cell's own stiffness. In fact, the stiffness values for the same scaffold sensed by the stiff and soft cells can differ from each other by an order of magnitude. The insights from this work will help in designing tissue engineering scaffolds for applications where mechanical stimuli are a critical factor.
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Affiliation(s)
- Dhruba Jyoti Mech
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Mohd Suhail Rizvi
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India
- Computational Biology Research Lab, IIT Hyderabad, Kandi, Sangareddy, Telangana 502284, India
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Song G, Gosain AK, Buganza Tepole A, Rhee K, Lee T. Exploring uncertainty in hyper-viscoelastic properties of scalp skin through patient-specific finite element models for reconstructive surgery. Comput Methods Biomech Biomed Engin 2024:1-15. [PMID: 38339988 DOI: 10.1080/10255842.2024.2313067] [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: 10/11/2023] [Accepted: 01/10/2024] [Indexed: 02/12/2024]
Abstract
Understanding skin responses to external forces is crucial for post-cutaneous flap wound healing. However, the in vivo viscoelastic behavior of scalp skin remains poorly understood. Personalized virtual surgery simulations offer a way to study tissue responses in relevant 3D geometries. Yet, anticipating wound risk remains challenging due to limited data on skin viscoelasticity, which hinders our ability to determine the interplay between wound size and stress levels. To bridge this gap, we reexamine three clinical cases involving scalp reconstruction using patient-specific geometric models and employ uncertainty quantification through a Monte Carlo simulation approach to study the effect of skin viscoelasticity on the final stress levels from reconstructive surgery. Utilizing the generalized Maxwell model via the Prony series, we can parameterize and efficiently sample a realistic range of viscoelastic response and thus shed light on the influence of viscoelastic material uncertainty in surgical scenarios. Our analysis identifies regions at risk of wound complications based on reported threshold stress values from the literature and highlights the significance of focusing on long-term responses rather than short-term ones.
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Affiliation(s)
- Gyohyeon Song
- Department of Intelligent Robotics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Arun K Gosain
- Surgery (Pediatric Surgery), Plastic Surgery, Lurie Children's Hospital of Chicago, Northwestern Feinberg School of Medicine, Chicago 60611, IL, United States
| | - Adrian Buganza Tepole
- Department of Mechanical Engineering, Purdue University, West Lafayette 47907, IN, United States
| | - Kyehan Rhee
- Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea
| | - Taeksang Lee
- Department of Mechanical Engineering, Myongji University, Yongin, 17058, Republic of Korea
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Keshavanarayana P, Spill F. A mechanical modeling framework to study endothelial permeability. Biophys J 2024; 123:334-348. [PMID: 38169215 PMCID: PMC10870174 DOI: 10.1016/j.bpj.2023.12.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/06/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024] Open
Abstract
The inner lining of blood vessels, the endothelium, is made up of endothelial cells. Vascular endothelial (VE)-cadherin protein forms a bond with VE-cadherin from neighboring cells to determine the size of gaps between the cells and thereby regulate the size of particles that can cross the endothelium. Chemical cues such as thrombin, along with mechanical properties of the cell and extracellular matrix are known to affect the permeability of endothelial cells. Abnormal permeability is found in patients suffering from diseases including cardiovascular diseases, cancer, and COVID-19. Even though some of the regulatory mechanisms affecting endothelial permeability are well studied, details of how several mechanical and chemical stimuli acting simultaneously affect endothelial permeability are not yet understood. In this article, we present a continuum-level mechanical modeling framework to study the highly dynamic nature of the VE-cadherin bonds. Taking inspiration from the catch-slip behavior that VE-cadherin complexes are known to exhibit, we model the VE-cadherin homophilic bond as cohesive contact with damage following a traction-separation law. We explicitly model the actin cytoskeleton and substrate to study their role in permeability. Our studies show that mechanochemical coupling is necessary to simulate the influence of the mechanical properties of the substrate on permeability. Simulations show that shear between cells is responsible for the variation in permeability between bicellular and tricellular junctions, explaining the phenotypic differences observed in experiments. An increase in the magnitude of traction force due to disturbed flow that endothelial cells experience results in increased permeability, and it is found that the effect is higher on stiffer extracellular matrix. Finally, we show that the cylindrical monolayer exhibits higher permeability than the planar monolayer under unconstrained cases. Thus, we present a contact mechanics-based mechanochemical model to investigate the variation in the permeability of endothelial monolayer due to multiple loads acting simultaneously.
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Affiliation(s)
| | - Fabian Spill
- School of Mathematics, University of Birmingham, Birmingham, United Kingdom.
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Nicolini LF, Oliveira RC, Ribeiro M, Stoffel M, Markert B, Kobbe P, Hildebrand F, Trobisch P, Simões MS, de Mello Roesler CR, Fancello EA. Tether pre-tension within vertebral body tethering reduces motion of the spine and influences coupled motion: a finite element analysis. Comput Biol Med 2024; 169:107851. [PMID: 38113683 DOI: 10.1016/j.compbiomed.2023.107851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 11/30/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
Anterior Vertebral Body Tethering (VBT) is a novel fusionless treatment option for selected adolescent idiopathic scoliosis patients which is gaining widespread interest. The primary objective of this study is to investigate the effects of tether pre-tension within VBT on the biomechanics of the spine including sagittal and transverse parameters as well as primary motion, coupled motion, and stresses acting on the L2 superior endplate. For that purpose, we used a calibrated and validated Finite Element model of the L1-L2 spine. The VBT instrumentation was inserted on the left side of the L1-L2 segment with different cord pre-tensions and submitted to an external pure moment of 6 Nm in different directions. The range of motion (ROM) for the instrumented spine was measured from the initial post-VBT position. The magnitudes of the ROM of the native spine and VBT-instrumented with pre-tensions of 100 N, 200 N, and 300 N were, respectively, 3.29°, 2.35°, 1.90° and 1.61° in extension, 3.30°, 3.46°, 2.79°, and 2.17° in flexion, 2.11°, 1.67°, 1.33° and 1.06° in right axial rotation, and 2.10°, 1.88°, 1.48° and 1.16° in left axial rotation. During flexion-extension, an insignificant coupled lateral bending motion was observed in the native spine. However, VBT instrumentation with pre-tensions of 100 N, 200 N, and 300 N generated coupled right lateral bending of 0.85°, 0.81°, and 0.71° during extension and coupled left lateral bending of 0.32°, 0.24°, and 0.19° during flexion, respectively. During lateral bending, a coupled extension motion of 0.33-0.40° is observed in the native spine, but VBT instrumentation with pre-tensions of 100 N, 200 N, and 300 N generates coupled flexion of 0.67°, 0.58°, and 0.42° during left (side of the implant) lateral bending and coupled extension of 1.28°, 1.07°, and 0.87° during right lateral bending, respectively. Therefore, vertebral body tethering generates coupled motion. Tether pre-tension within vertebral body tethering reduces the motion of the spine.
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Affiliation(s)
- Luis Fernando Nicolini
- Group of Analysis and Mechanical Design - GRANTE, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil; Mechanical and Aerospace Technology Laboratory (NUMAE), Dep. of Mechanical Engineering, Federal University of Santa Maria, Brazil.
| | - Rafael Carreira Oliveira
- Group of Analysis and Mechanical Design - GRANTE, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil
| | - Marx Ribeiro
- Group of Analysis and Mechanical Design - GRANTE, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil; Department of Orthopedics, Trauma and Reconstructive Surgery, RWTH Aachen University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Marcus Stoffel
- Institute of General Mechanics (IAM), RWTH Aachen University, Germany
| | - Bernd Markert
- Institute of General Mechanics (IAM), RWTH Aachen University, Germany
| | - Philipp Kobbe
- Department of Orthopedics, Trauma and Reconstructive Surgery, RWTH Aachen University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Frank Hildebrand
- Department of Orthopedics, Trauma and Reconstructive Surgery, RWTH Aachen University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany
| | | | - Marcelo Simoni Simões
- Biomechanical Engineering Laboratory - LEBm, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil
| | - Carlos Rodrigo de Mello Roesler
- Group of Analysis and Mechanical Design - GRANTE, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil; Biomechanical Engineering Laboratory - LEBm, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil
| | - Eduardo Alberto Fancello
- Group of Analysis and Mechanical Design - GRANTE, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil; Biomechanical Engineering Laboratory - LEBm, Dep. of Mechanical Engineering, Federal University of Santa Catarina, Brazil
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Campos T, Araújo R, Xavier J, Nguyễn Q, Dourado N, Morais J, Pereira F. Identification of Apple Fruit-Skin Constitutive Laws by Full-Field Methods Using Uniaxial Tensile Loading. MATERIALS (BASEL, SWITZERLAND) 2024; 17:700. [PMID: 38591566 PMCID: PMC10856416 DOI: 10.3390/ma17030700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 04/10/2024]
Abstract
The protective and preservative role of apple skin in maintaining the integrity of the fruit is well-known, with its mechanical behaviour playing a pivotal role in determining fruit storage capacity. This study employs a combination of experimental and numerical methodologies, specifically utilising the digital image correlation (DIC) technique. A specially devised inverse strategy is applied to evaluate the mechanical behaviour of apple skin under uniaxial tensile loading. Three apple cultivars were tested in this work: Malus domestica Starking Delicious, Malus pumila Rennet, and Malus domestica Golden Delicious. Stress-strain curves were reconstructed, revealing distinct variations in the mechanical responses among these cultivars. Yeoh's hyperelastic model was fitted to the experimental data to identify the coefficients capable of reproducing the non-linear deformation. The results suggest that apple skin varies significantly in composition and structure among the tested cultivars, as evidenced by differences in elastic properties and non-linear behaviour. These differences can significantly affect how fruit is handled, stored, and transported. Thus, the insights resulting from this research enable the development of mathematical models based on the mechanical behaviour of apple tissue, constituting important data for improvements in the economics of the agri-food industry.
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Affiliation(s)
- Teresa Campos
- CMEMS-UMINHO, Universidade do Minho, 4800-058 Guimarães, Portugal (N.D.)
- LABBELS–Associate Laboratory, 4800-058 Guimarães, Portugal
| | - Rafael Araújo
- CITAB/UTAD, Departamento de Engenharias, Quinta de Prados, 5001-801 Vila Real, Portugal (J.M.); (F.P.)
| | - José Xavier
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- LASI, Intelligent Systems Associate Laboratory, 4800-058 Guimarães, Portugal
| | - Quyền Nguyễn
- 2C2T-Centro de Ciência e Tecnologia Têxtil, Universidade do Minho, 4800-058 Guimarães, Portugal
| | - Nuno Dourado
- CMEMS-UMINHO, Universidade do Minho, 4800-058 Guimarães, Portugal (N.D.)
- LABBELS–Associate Laboratory, 4800-058 Guimarães, Portugal
| | - José Morais
- CITAB/UTAD, Departamento de Engenharias, Quinta de Prados, 5001-801 Vila Real, Portugal (J.M.); (F.P.)
| | - Fábio Pereira
- CITAB/UTAD, Departamento de Engenharias, Quinta de Prados, 5001-801 Vila Real, Portugal (J.M.); (F.P.)
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Tang J, Liu W, Li X, Peng Y, Zhang Y, Hou S. Linking myosin heavy chain isoform shift to mechanical properties and fracture modes in skeletal muscle tissue. Biomech Model Mechanobiol 2024; 23:103-116. [PMID: 37568047 DOI: 10.1007/s10237-023-01761-y] [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: 05/17/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023]
Abstract
Muscle fibers play a crucial role in the mechanical action of skeletal muscle tissue. However, it is unclear how the histological variations affect the mechanical properties of tissues. In this study, the shift of myosin heavy chain (MHC) isoforms is used for the first time to establish a linkage between tissue histological variation and passive mechanical properties. The shift of MHC isoform is found not only to induce significant differences in skeletal muscle passive mechanical properties, but also to lead to differences in strain rate responses. Non-negligible rate dependence is observed even in the conventionally defined quasi-static regime. Fidelity in the estimated constitutive parameters, which can be impacted due to variation in MHC isoforms and hence in rate sensitivity, is enhanced using a Bayesian inference framework. Subsequently, scanning electron microscopy and fluorescence microscopy are used to characterize the fracture morphology of muscle tissues and fibers. The fracture mode of both MHC I and II muscle fibers exhibited shearing of endomysium. Results show that the increase in strain rate only leads to stronger rebounding of the muscle fibers during tissue rupture without changing fracture modes.
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Affiliation(s)
- Jiabao Tang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, 410082, China
| | - Wenyang Liu
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, 410082, China.
| | - Xuhong Li
- The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yun Peng
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Shujuan Hou
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, 410082, China
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