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Sarantides P, Raptis A, Mathioulakis D, Moulakakis K, Kakisis J, Manopoulos C. Computational Study of Abdominal Aortic Aneurysm Walls Accounting for Patient-Specific Non-Uniform Intraluminal Thrombus Thickness and Distinct Material Models: A Pre- and Post-Rupture Case. Bioengineering (Basel) 2024; 11:144. [PMID: 38391630 PMCID: PMC10886172 DOI: 10.3390/bioengineering11020144] [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: 11/30/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
An intraluminal thrombus (ILT) is present in the majority of abdominal aortic aneurysms, playing a crucial role in their growth and rupture. Although most computational studies do not include the ILT, in the present study, this is taken into account, laying out the whole simulation procedure, namely, from computed tomography scans to medical image segmentation, geometry reconstruction, mesh generation, biomaterial modeling, finite element analysis, and post-processing, all carried out in open software. By processing the tomography scans of a patient's aneurysm before and after rupture, digital twins are reconstructed assuming a uniform aortic wall thickness. The ILT and the aortic wall are assigned different biomaterial models; namely, the first is modeled as an isotropic linear elastic material, and the second is modeled as the Mooney-Rivlin hyperelastic material as well as the transversely isotropic hyperelastic Holzapfel-Gasser-Ogden nonlinear material. The implementation of the latter requires the designation of local Cartesian coordinate systems in the aortic wall, suitably oriented in space, for the proper orientation of the collagen fibers. The composite aneurysm geometries (ILT and aortic wall structures) are loaded with normal and hypertensive static intraluminal pressure. Based on the calculated stress and strain distributions, ILT seems to be protecting the aneurysm from a structural point of view, as the highest stresses appear in the thrombus-free areas of the aneurysmal wall.
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Affiliation(s)
- Platon Sarantides
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
| | - Anastasios Raptis
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
| | - Dimitrios Mathioulakis
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
- School of Engineering, Bahrain Polytechnic, Isa Town P.O. Box 33349, Bahrain
| | - Konstantinos Moulakakis
- Department of Vascular Surgery, School of Medicine, University of Patras, 265 04 Patras, Greece
| | - John Kakisis
- Department of Vascular Surgery, Attikon University Hospital, National and Kapodistrian University of Athens, 106 79 Athens, Greece
| | - Christos Manopoulos
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
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Fan X, Zhang A, Zheng Q, Li P, Wang Y, He L, Xue Y, Chen W, Wu X, Zhao Y, Wang Y. The biomechanical effects of different membrane layer structures and material constitutive modeling on patient-specific cerebral aneurysms. Front Bioeng Biotechnol 2024; 11:1323266. [PMID: 38288243 PMCID: PMC10822973 DOI: 10.3389/fbioe.2023.1323266] [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: 10/17/2023] [Accepted: 12/29/2023] [Indexed: 01/31/2024] Open
Abstract
The prevention, control and treatment of cerebral aneurysm (CA) has become a common concern of human society, and by simulating the biomechanical environment of CA using finite element analysis (FEA), the risk of aneurysm rupture can be predicted and evaluated. The target models of the current study are mainly idealized single-layer linear elastic cerebral aneurysm models, which do not take into account the effects of the vessel wall structure, material constitution, and structure of the real CA model on the mechanical parameters. This study proposes a reconstruction method for patient-specific trilaminar CA structural modeling. Using two-way fluid-structure interaction (FSI), we comparatively analyzed the effects of the differences between linear and hyperelastic materials and three-layer and single-layer membrane structures on various hemodynamic parameters of the CA model. It was found that the numerical effects of the different CA membrane structures and material constitution on the stresses and wall deformations were obvious, but does not affect the change in its distribution pattern and had little effect on the blood flow patterns. For the same material constitution, the stress of the three-layer membrane structure were more than 10.1% larger than that of the single-layer membrane structure. For the same membrane structure, the stress of the hyperelastic material were more than 5.4% larger than that of the linear elastic material, and the displacement of the hyperelastic material is smaller than that of the linear elastic material by about 20%. And the maximum value of stress occurred in the media, and the maximum displacement occurred in the intima. In addition, the upper region of the tumor is the maximum rupture risk region for CA, and the neck of the tumor and the bifurcation of the artery are also the sub-rupture risk regions to focus on. This study can provide data support for the selection of model materials for CA simulation and analysis, as well as a theoretical basis for clinical studies and subsequent research methods.
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Affiliation(s)
- Xuanze Fan
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Aohua Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Qingli Zheng
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Pengcui Li
- Shanxi Provincial Key Laboratory for Repair of Bone and Soft Tissue Injury, Taiyuan, China
| | - Yanqin Wang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Liming He
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China
| | - Yanru Xue
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China
| | - Weiyi Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Xiaogang Wu
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China
| | | | - Yonghong Wang
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China
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Kuyanova J, Dubovoi A, Fomichev A, Khelimskii D, Parshin D. Hemodynamics of vascular shunts: trends, challenges, and prospects. Biophys Rev 2023; 15:1287-1301. [PMID: 37975016 PMCID: PMC10643646 DOI: 10.1007/s12551-023-01149-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 09/12/2023] [Indexed: 11/19/2023] Open
Abstract
Vascular bypass surgery takes a significant place in the treatment of vascular disease. According to various assessments, this type of surgery is associated with almost 20 % of all vascular surgery episodes (up to 23 % according to the Federal Neurosurgical Center of Novosibirsk). Even though the problem of using of vascular grafts is obvious and natural, many problems associated with them are not still elucidated. From the mechanics' point of view, a vascular bypass is a converging or diverging tee, and the functioning of such structures still does not have strict mathematical formulations and proofs in the general case, which forces many researchers to solve specific engineering problems associated with shunting. Mathematical modeling, which is the gold standard for virtual simulations of industrial and medical problems, faces great difficulties and limitations in solving problems for vascular bypasses. Complications in the treatment of the vascular disease may follow the difficulties in mathematical modeling, and the price can be a cardiac arrest or a stroke. This work is devoted to the main aspects of the medical application of vascular bypasses and their functioning as a mechanical system, as well the mathematical aspects of their possible setup.
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Affiliation(s)
- Julia Kuyanova
- Department, Lavrentyev Institute of Hydrodynamics SB RAS, Ac. Lavrentieva ave., Novosibirsk, 630090 Russian Federation
| | - Andrei Dubovoi
- Department, FSBI “Federal Neurosurgical Center”, Nemirovicha-Danchenko st., Novosibirsk, 630087 Russian Federation
| | - Aleksei Fomichev
- Department, Meshalkin National Medical Research Center, Rechkunovskaya st., Novosibirsk, 610101 Russian Federation
| | - Dmitrii Khelimskii
- Department, Meshalkin National Medical Research Center, Rechkunovskaya st., Novosibirsk, 610101 Russian Federation
| | - Daniil Parshin
- Department, Lavrentyev Institute of Hydrodynamics SB RAS, Ac. Lavrentieva ave., Novosibirsk, 630090 Russian Federation
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Khinsoe G, Bappoo N, Kelsey LJ, Blom D, Doyle BJ, Jansen S. Computational biomechanics: a potential new tool for the vascular surgeon in personalized management. ANZ J Surg 2022; 92:1308-1311. [PMID: 35688636 DOI: 10.1111/ans.17476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 11/16/2021] [Accepted: 12/21/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Georgia Khinsoe
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Nikhilesh Bappoo
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Dirk Blom
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,Curtin Medical School, Curtin University, Perth, Western Australia, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia.,Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK.,Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Shirley Jansen
- Curtin Medical School, Curtin University, Perth, Western Australia, Australia.,Heart and Vascular Research Institute, Harry Perkins Institute of Medical Research, QEII Medical Centre, Perth, Western Australia, Australia.,Department of Vascular and Endovascular Surgery, Sir Charles Gardiner Hospital, Perth, Western Australia, Australia.,Medical School, The University of Western Australia, Perth, Western Australia, Australia
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Bianchi D, Marino M, Vairo G. An integrated computational approach for aortic mechanics including geometric, histological and chemico-physical data. J Biomech 2016; 49:2331-40. [DOI: 10.1016/j.jbiomech.2016.01.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 01/28/2016] [Indexed: 02/01/2023]
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6
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Joldes GR, Miller K, Wittek A, Doyle B. A simple, effective and clinically applicable method to compute abdominal aortic aneurysm wall stress. J Mech Behav Biomed Mater 2016; 58:139-148. [PMID: 26282385 DOI: 10.1016/j.jmbbm.2015.07.029] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/22/2015] [Accepted: 07/27/2015] [Indexed: 10/23/2022]
Affiliation(s)
- Grand Roman Joldes
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Karol Miller
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
| | - Adam Wittek
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Barry Doyle
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia; Centre for Cardiovascular Science, The University of Edinburgh, UK
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7
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Phan L, Courchaine K, Azarbal A, Vorp D, Grimm C, Rugonyi S. A Geodesics-Based Surface Parameterization to Assess Aneurysm Progression. J Biomech Eng 2016; 138:054503. [PMID: 27003915 DOI: 10.1115/1.4033082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Indexed: 12/15/2022]
Abstract
Abdominal aortic aneurysm (AAA) intervention and surveillance is currently based on maximum transverse diameter, even though it is recognized that this might not be the best strategy. About 10% of patients with small AAA transverse diameters, for whom intervention is not considered, still rupture; while patients with large AAA transverse diameters, for whom intervention would have been recommended, have stable aneurysms that do not rupture. While maximum transverse diameter is easy to measure and track in clinical practice, one of its main drawbacks is that it does not represent the whole AAA and rupture seldom occurs in the region of maximum transverse diameter. By following maximum transverse diameter alone clinicians are missing information on the shape change dynamics of the AAA, and clues that could lead to better patient care. We propose here a method to register AAA surfaces that were obtained from the same patient at different time points. Our registration method could be used to track the local changes of the patient-specific AAA. To achieve registration, our procedure uses a consistent parameterization of the AAA surfaces followed by strain relaxation. The main assumption of our procedure is that growth of the AAA occurs in such a way that surface strains are smoothly distributed, while regions of small and large surface growth can be differentiated. The proposed methodology has the potential to unravel different patterns of AAA growth that could be used to stratify patient risks.
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Doyle BJ, Miller K, Newby DE, Hoskins PR. Commentary: Computational Biomechanics–Based Rupture Prediction of Abdominal Aortic Aneurysms. J Endovasc Ther 2016; 23:121-4. [DOI: 10.1177/1526602815615821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Barry J. Doyle
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Scotland, UK
| | - Karol Miller
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
- Institute of Mechanics and Advanced Materials, Cardiff University, Cardiff, Wales, UK
| | - David E. Newby
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Scotland, UK
- Clinical Research Imaging Centre, University of Edinburgh, Scotland, UK
| | - Peter R. Hoskins
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Scotland, UK
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9
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Georg Y, Delay C, Schwein A, Lejay A, Thaveau F, Gaertner S, Stephan D, Heim F, Chakfe N. [Contribution of mathematical models and biomechanical properties in predicting the risk of abdominal aortic aneurysm rupture]. ACTA ACUST UNITED AC 2015; 41:63-8. [PMID: 26318549 DOI: 10.1016/j.jmv.2015.07.107] [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: 01/16/2015] [Accepted: 07/17/2015] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Rupture is the worst outcome of abdominal aortic aneurysm (AAA). The decision to operate should include counterbalancing the risk of aneurysm rupture against the risk of aneurysm repair, within the context of a patient's overall life expectancy. Current surgical guidelines are based on population studies, and important variables are missed in predicting individual risk of rupture. METHODS In this literature review, we focused on the contribution of biomechanical and mathematical models in predicting risk of AAA rupture. RESULTS Anatomical features as diameter asymmetry and lack of tortuosity are shown to be anatomical risk factors of rupture. Wall stiffness (due to modifications of elastin and collagen composition) and increased inflammatory response are also factors that affect the structural integrity of the AAA wall. Biomechanical studies showed that wall strength is lower in ruptured than non-ruptured AAA. Intra-luminal thrombus also has a big role to play in the occurrence of rupture. Current mathematical models allow more variables to be included in predicting individual risk of rupture. CONCLUSION Moving away from using maximal transverse diameter of the AAA as a unique predictive factor and instead including biological, structural and biomechanical variables in predicting individual risk of rupture will be essential in the future and will help gain precision and accuracy in surgical indications.
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Affiliation(s)
- Y Georg
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Service de chirurgie vasculaire et transplantation rénale, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP n(o) 426, 67091 Strasbourg cedex, France
| | - C Delay
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Service de chirurgie vasculaire et transplantation rénale, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP n(o) 426, 67091 Strasbourg cedex, France
| | - A Schwein
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Service de chirurgie vasculaire et transplantation rénale, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP n(o) 426, 67091 Strasbourg cedex, France
| | - A Lejay
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Service de chirurgie vasculaire et transplantation rénale, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP n(o) 426, 67091 Strasbourg cedex, France
| | - F Thaveau
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Service de chirurgie vasculaire et transplantation rénale, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP n(o) 426, 67091 Strasbourg cedex, France
| | - S Gaertner
- Service des maladies vasculaires, hypertension artérielle et pharmacologie clinique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67091 Strasbourg cedex, France
| | - D Stephan
- Service des maladies vasculaires, hypertension artérielle et pharmacologie clinique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67091 Strasbourg cedex, France
| | - F Heim
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Laboratoire de physique et mécanique textile, ENSISA, 11, rue Alfred-Werner, 68093 Mulhouse cedex, France
| | - N Chakfe
- Groupe européen de recherche sur les prothèses appliquées à la chirurgie vasculaire (Geprovas), faculté de médecine, institut d'anatomie pathologique, 4, rue Kirschleger, 67085 Strasbourg cedex, France; Service de chirurgie vasculaire et transplantation rénale, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP n(o) 426, 67091 Strasbourg cedex, France.
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10
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Patient specific stress and rupture analysis of ascending thoracic aneurysms. J Biomech 2015; 48:1836-43. [DOI: 10.1016/j.jbiomech.2015.04.035] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/30/2015] [Accepted: 04/23/2015] [Indexed: 11/17/2022]
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11
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Computational Biomechanics in Thoracic Aortic Dissection: Today’s Approaches and Tomorrow’s Opportunities. Ann Biomed Eng 2015; 44:71-83. [DOI: 10.1007/s10439-015-1366-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 06/11/2015] [Indexed: 01/16/2023]
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12
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Determining the influence of calcification on the failure properties of abdominal aortic aneurysm (AAA) tissue. J Mech Behav Biomed Mater 2015; 42:154-67. [DOI: 10.1016/j.jmbbm.2014.11.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/21/2014] [Accepted: 11/03/2014] [Indexed: 11/20/2022]
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13
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Simsek FG, Kwon YW. Investigation of material modeling in fluid-structure interaction analysis of an idealized three-layered abdominal aorta: aneurysm initiation and fully developed aneurysms. J Biol Phys 2015; 41:173-201. [PMID: 25624113 DOI: 10.1007/s10867-014-9372-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 11/06/2014] [Indexed: 01/26/2023] Open
Abstract
Different material models for an idealized three-layered abdominal aorta are compared using computational techniques to study aneurysm initiation and fully developed aneurysms. The computational model includes fluid-structure interaction (FSI) between the blood vessel and the blood. In order to model aneurysm initiation, the medial region was degenerated to mimic the medial loss occurring in the inception of an aneurysm. Various cases are considered in order to understand their effects on the initiation of an abdominal aortic aneurysm. The layers of the blood vessel were modeled using either linear elastic materials or Mooney-Rivlin (otherwise known as hyperelastic) type materials. The degenerated medial region was also modeled in either linear elastic or hyperelastic-type materials and assumed to be in the shape of an arc with a thin width or a circular ring with different widths. The blood viscosity effect was also considered in the initiation mechanism. In addition, dynamic analysis of the blood vessel was performed without interaction with the blood flow by applying time-dependent pressure inside the lumen in a three-layered abdominal aorta. The stresses, strains, and displacements were compared for a healthy aorta, an initiated aneurysm and a fully developed aneurysm. The study shows that the material modeling of the vessel has a sizable effect on aneurysm initiation and fully developed aneurysms. Different material modeling of degeneration regions also affects the stress-strain response of aneurysm initiation. Additionally, the structural analysis without considering FSI (called noFSI) overestimates the peak von Mises stress by 52% at the interfaces of the layers.
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Affiliation(s)
- Fatma Gulden Simsek
- Institute of Biomedical Engineering, Bogazici University, Kandilli Camp, Istanbul, Turkey,
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14
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Xenos M, Labropoulos N, Rambhia S, Alemu Y, Einav S, Tassiopoulos A, Sakalihasan N, Bluestein D. Progression of abdominal aortic aneurysm towards rupture: refining clinical risk assessment using a fully coupled fluid-structure interaction method. Ann Biomed Eng 2014; 43:139-53. [PMID: 25527320 DOI: 10.1007/s10439-014-1224-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/09/2014] [Indexed: 01/12/2023]
Abstract
Rupture of abdominal aortic aneurysm (AAA) is associated with high mortality rates. Risk of rupture is multi-factorial involving AAA geometric configuration, vessel tortuosity, and the presence of intraluminal pathology. Fluid structure interaction (FSI) simulations were conducted in patient based computed tomography scans reconstructed geometries in order to monitor aneurysmal disease progression from normal aortas to non-ruptured and contained ruptured AAA (rAAA), and the AAA risk of rupture was assessed. Three groups of 8 subjects each were studied: 8 normal and 16 pathological (8 non-ruptured and 8 rAAA). The AAA anatomical structures segmented included the blood lumen, intraluminal thrombus (ILT), vessel wall, and embedded calcifications. The vessel wall was described with anisotropic material model that was matched to experimental measurements of AAA tissue specimens. A statistical model for estimating the local wall strength distribution was employed to generate a map of a rupture potential index (RPI), representing the ratio between the local stress and local strength distribution. The FSI simulations followed a clear trend of increasing wall stresses from normal to pathological cases. The maximal stresses were observed in the areas where the ILT was not present, indicating a potential protective effect of the ILT. Statistically significant differences were observed between the peak systolic stress and the peak stress at the mean arterial pressure between the three groups. For the ruptured aneurysms, where the geometry of intact aneurysm was reconstructed, results of the FSI simulations clearly depicted maximum wall stress at the a priori known location of rupture. The RPI mapping indicated several distinct regions of high RPI coinciding with the actual location of rupture. The FSI methodology demonstrates that the aneurysmal disease can be described by numerical simulations, as indicated by a clear trend of increasing aortic wall stresses in the studied groups, (normal aortas, AAAs and rAAAs). Ultimately, the results demonstrate that FSI wall stress mapping and RPI can be used as a tool for predicting the potential rupture of an AAA by predicting the actual rupture location, complementing current clinical practice by offering a predictive diagnostic tool for deciding whether to intervene surgically or spare the patient from an unnecessary risky operation.
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Affiliation(s)
- Michalis Xenos
- Department of Mathematics, University of Ioannina, Ioannina, Greece
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15
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O’Leary SA, Healey DA, Kavanagh EG, Walsh MT, McGloughlin TM, Doyle BJ. The Biaxial Biomechanical Behavior of Abdominal Aortic Aneurysm Tissue. Ann Biomed Eng 2014; 42:2440-50. [DOI: 10.1007/s10439-014-1106-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/28/2014] [Indexed: 11/24/2022]
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16
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O’Leary SA, Doyle BJ, McGloughlin TM. The impact of long term freezing on the mechanical properties of porcine aortic tissue. J Mech Behav Biomed Mater 2014; 37:165-73. [DOI: 10.1016/j.jmbbm.2014.04.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/21/2014] [Accepted: 04/27/2014] [Indexed: 11/26/2022]
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17
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O׳Leary SA, Kavanagh EG, Grace PA, McGloughlin TM, Doyle BJ. The biaxial mechanical behaviour of abdominal aortic aneurysm intraluminal thrombus: Classification of morphology and the determination of layer and region specific properties. J Biomech 2014; 47:1430-7. [DOI: 10.1016/j.jbiomech.2014.01.041] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/29/2013] [Accepted: 01/18/2014] [Indexed: 10/25/2022]
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Boileau E, Bevan RLT, Sazonov I, Rees MI, Nithiarasu P. Flow-induced ATP release in patient-specific arterial geometries--a comparative study of computational models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2013; 29:1038-1056. [PMID: 23894050 DOI: 10.1002/cnm.2581] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 06/02/2023]
Abstract
The importance of the endothelium in the local regulation of blood flow is reflected by its influence on vascular tone by means of vasodilatory responses to many physiological stimuli. Regulatory pathways are affected by mass transport and wall shear stress (WSS), via mechanotransduction mechanisms. In the present work, we review the most relevant computational models that have been proposed to date, and introduce a general framework for modelling the responses of the endothelium to alteration in the flow, with a view to understanding the biomechanical processes involved in the pathways to endothelial dysfunction. Simulations are performed on two different patient-specific stenosed carotid artery geometries to investigate the influence of WSS and mass transport phenomena upon the agonist coupling response at the endothelium. In particular, results presented for two different models of WSS-dependent adenosine-5'-triphosphate (ATP) release reveal that existing paradigms may not account for the conditions encountered in vivo and may therefore not be adequate to model the kinetics of ATP at the endothelium.
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Affiliation(s)
- E Boileau
- College of Engineering, Swansea University, Swansea, SA2 8PP, UK
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Comparison of methods used to measure the thickness of soft tissues and their influence on the evaluation of tensile stress. J Biomech 2013; 46:1955-60. [DOI: 10.1016/j.jbiomech.2013.05.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 05/04/2013] [Accepted: 05/08/2013] [Indexed: 11/20/2022]
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