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Raviol J, Plet G, Hasegawa R, Yu K, Kosukegawa H, Ohta M, Magoariec H, Pailler-Mattei C. Towards the mechanical characterisation of unruptured intracranial aneurysms: Numerical modelling of interactions between a deformation device and the aneurysm wall. J Mech Behav Biomed Mater 2024; 153:106469. [PMID: 38402693 DOI: 10.1016/j.jmbbm.2024.106469] [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: 12/05/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
Intracranial aneurysm is a critical pathology related to the arterial wall deterioration. This work is an essential aspect of a large scale project aimed at providing clinicians with a non-invasive patient-specific decision support tool regarding the rupture risk assessment. A machine learning algorithm links the aneurysm shape observed and a database of UIA clinical images associated with in vivo wall mechanical properties and rupture characterisation. The database constitution is derived from a device prototype coupled with medical imaging. It provides the mechanical characterisation of the aneurysm from the wall deformation obtained by inverse analysis based on the variation of luminal volume. Before performing in vivo tests of the device on small animals, a numerical model was built to quantify the device's impact on the aneurysm wall under natural blood flow conditions. As the clinician will never be able to precisely situate the device, several locations were considered. In preparation for the inverse analysis procedure, artery material laws of increasing complexity were studied (linear elastic, hyper elastic Fung-like). Considering all the device locations and material laws, the device induced relative displacements to the Systole peak (worst case scenario with the highest mechanical stimulus linked to the blood flow) ranging from 375 μm to 1.28 mm. The variation of luminal volume associated with the displacements was between 0.95 % and 4.3 % compared to the initial Systole volume of the aneurysm. Significant increase of the relative displacements and volume variations were found with the study of different cardiac cycle moments between the blood flow alone and the device application. For forthcoming animal model studies, Spectral Photon CT Counting, with a minimum spatial resolution of 250 μm, was selected as the clinical imaging technique. Based on this preliminary study, the displacements and associated volume variations (baseline for inverse analyse), should be observable and exploitable.
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Affiliation(s)
- J Raviol
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, Université de Lyon, École Centrale de Lyon, France
| | - G Plet
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, Université de Lyon, École Centrale de Lyon, France
| | - R Hasegawa
- Graduate School of Engineering, Tohuku University, 980-8579, Sendai Miyagi, Japan; Institute of Fluid Science, Tohuku University, 980-8577, Sendai Miyagi, Japan
| | - K Yu
- Institute of Fluid Science, Tohuku University, 980-8577, Sendai Miyagi, Japan
| | - H Kosukegawa
- Institute of Fluid Science, Tohuku University, 980-8577, Sendai Miyagi, Japan
| | - M Ohta
- Institute of Fluid Science, Tohuku University, 980-8577, Sendai Miyagi, Japan; ElyT MaX, CNRS UMI 3537, Université de Lyon, Tohoku University, France, Japan
| | - H Magoariec
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, Université de Lyon, École Centrale de Lyon, France
| | - C Pailler-Mattei
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, Université de Lyon, École Centrale de Lyon, France; ISPB-Faculté de Pharmacie, Université Claude Bernard Lyon 1, Université de Lyon, France.
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2
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Melo SF, Nondonfaz A, Aqil A, Pierrard A, Hulin A, Delierneux C, Ditkowski B, Gustin M, Legrand M, Tullemans BME, Brouns SLN, Nchimi A, Carrus R, Dejosé A, Heemskerk JWM, Kuijpers MJE, Ritter J, Steinseifer U, Clauser JC, Jérôme C, Lancellotti P, Oury C. Design, manufacturing and testing of a green non-isocyanate polyurethane prosthetic heart valve. Biomater Sci 2024; 12:2149-2164. [PMID: 38487997 DOI: 10.1039/d3bm01911j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
The sole effective treatment for most patients with heart valve disease is valve replacement by implantation of mechanical or biological prostheses. However, mechanical valves represent high risk of thromboembolism, and biological prostheses are prone to early degeneration. In this work, we aim to determine the potential of novel environmentally-friendly non-isocyanate polyurethanes (NIPUs) for manufacturing synthetic prosthetic heart valves. Polyhydroxyurethane (PHU) NIPUs are synthesized via an isocyanate-free route, tested in vitro, and used to produce aortic valves. PHU elastomers reinforced with a polyester mesh show mechanical properties similar to native valve leaflets. These NIPUs do not cause hemolysis. Interestingly, both platelet adhesion and contact activation-induced coagulation are strongly reduced on NIPU surfaces, indicating low thrombogenicity. Fibroblasts and endothelial cells maintain normal growth and shape after indirect contact with NIPUs. Fluid-structure interaction (FSI) allows modeling of the ideal valve design, with minimal shear stress on the leaflets. Injection-molded valves are tested in a pulse duplicator and show ISO-compliant hydrodynamic performance, comparable to clinically-used bioprostheses. Poly(tetrahydrofuran) (PTHF)-NIPU patches do not show any evidence of calcification over a period of 8 weeks. NIPUs are promising sustainable biomaterials for the manufacturing of improved prosthetic valves with low thrombogenicity.
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Affiliation(s)
- Sofia F Melo
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Alicia Nondonfaz
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Abdelhafid Aqil
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, Department of Chemistry, University of Liège, Allée du 6 août 13, B6a, 4000 Liège, Belgium
| | - Anna Pierrard
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, Department of Chemistry, University of Liège, Allée du 6 août 13, B6a, 4000 Liège, Belgium
| | - Alexia Hulin
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Céline Delierneux
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Bartosz Ditkowski
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Maxime Gustin
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Maxime Legrand
- Sirris, Liège Science Park, Rue du Bois Saint-Jean 12, 4102 Seraing, Belgium
| | - Bibian M E Tullemans
- Cardiovascular Research Institute Maastricht (CARIM), Department of Biochemistry, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
| | - Sanne L N Brouns
- Cardiovascular Research Institute Maastricht (CARIM), Department of Biochemistry, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
| | - Alain Nchimi
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Raoul Carrus
- Sirris, Liège Science Park, Rue du Bois Saint-Jean 12, 4102 Seraing, Belgium
| | - Astrid Dejosé
- Sirris, Liège Science Park, Rue du Bois Saint-Jean 12, 4102 Seraing, Belgium
| | - Johan W M Heemskerk
- Cardiovascular Research Institute Maastricht (CARIM), Department of Biochemistry, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
| | - Marijke J E Kuijpers
- Cardiovascular Research Institute Maastricht (CARIM), Department of Biochemistry, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
| | - Jan Ritter
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty RWTH Aachen University, Pauwelsstraße 20, 52074 Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty RWTH Aachen University, Pauwelsstraße 20, 52074 Aachen, Germany
| | - Johanna C Clauser
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty RWTH Aachen University, Pauwelsstraße 20, 52074 Aachen, Germany
| | - Christine Jérôme
- Center for Education and Research on Macromolecules (CERM), CESAM Research Unit, Department of Chemistry, University of Liège, Allée du 6 août 13, B6a, 4000 Liège, Belgium
| | - Patrizio Lancellotti
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
| | - Cécile Oury
- Laboratory of Cardiology, GIGA-Cardiovascular Sciences, University of Liège, Avenue de l'Hôpital 11, B34, 4000 Liège, Belgium.
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Zhou G, Wang J, Liu W, Gu W, Su M, Feng Y, Qin B, Zhu Y. An assessment of how the anterior cerebral artery anatomy impacts ACoA aneurysm formation based on CFD analysis. Br J Neurosurg 2024; 38:215-219. [PMID: 32988230 DOI: 10.1080/02688697.2020.1821867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/26/2020] [Accepted: 09/04/2020] [Indexed: 12/27/2022]
Abstract
OBJECTIVE The aim of this study was to identify independent anatomic, morphologic and hemodynamic features of the ACoA (anterior communicating artery) complex that serve as risk factors for the occurrence of ACoA aneurysms. METHODS Fifteen consecutive patients with 15 ACoA aneurysms were included. Computational fluid dynamics (CFD) simulations based on patient-specific models were carried out using 3D time-of-flight magnetic resonance angiography (3D-TOF-MRA) images. A reverse reconstruction technique was used to generate a pre-aneurysm vessel anatomy. Geometric parameters and hemodynamic changes were compared and evaluated. RESULTS The overall prevalence of symmetric, dysplastic, and absent A1 segments were 53.3%, 26.7%, and 20%. The mean wall shear stress (WSS) of the absent group (AG) was significantly higher than that of the symmetric group (SG) and dysplastic group (DG). The absolute mean A1 artery flow rate (410.2 ± 88 versus 439.4 ± 101 mL/min; p = .45) of the aneurysm side was similar between the SG and DG but significantly higher in the AG (528.1 ± 77 mL/min; p < .05). The A1-A2 angles of the aneurysm side showed no significant differences among the 3 groups (p = .32). However, the mean A1-A2 angle on the aneurysm side was smaller than the contralateral A1-A2 angle (101.9 ± 9.1˚ versus 120.3 ± 7.7˚; p <.05). A regression analysis demonstrated that high WSS was significantly associated with a large A1-A2 ratio (R2=0.52; p <.05). CONCLUSIONS ACoA aneurysms are a high-WSS pathology. Severe flow impingement and the anatomic vasculature structures play a role in triggering the occurrence of ACoA aneurysms.
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Affiliation(s)
- Geng Zhou
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Jienan Wang
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Weidong Liu
- Department of Neurosurgery, Shanghai Punan Hospital, Shanghai, China
| | - Wenquan Gu
- Department of Neurosurgery, Shanghai Punan Hospital, Shanghai, China
| | - Ming Su
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yong Feng
- Shanghai Micro-Invention Medical Devices Co., Ltd, Shanghai, China
| | - Binjie Qin
- Department of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yueqi Zhu
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
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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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5
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Constantin BD, Simão da Silva E, Lessard S, Kauffman C, Soulez G. Morphology of Abdominal Aortic Aneurysms and Correlation with Biomechanical Tests of Aneurysmal Wall Fragments. Ann Vasc Surg 2024; 100:101-109. [PMID: 38110080 DOI: 10.1016/j.avsg.2023.10.017] [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: 08/31/2023] [Revised: 09/30/2023] [Accepted: 10/17/2023] [Indexed: 12/20/2023]
Abstract
BACKGROUND Evaluate how specific morphologic aspects of abdominal aortic aneurysms (AAAs), including asymmetries, curvatures, tortuosities, and angulations, among others can influence the intrinsic biomechanical properties of the AAA's wall. This study analyzed the correlation of geometric measurements (1-dimensional, 2-dimensional, and 3-dimensional) of preoperative tomographic images of AAA with uniaxial biomechanical tests of the arterial wall fragments of these AAA obtained in open surgical repair of aneurysms. METHODS It was a multicenter, experimental, and observational study, and initially 54 individuals were selected who underwent open surgical of AAA, with valid biomechanical tests of the anterior wall of the AAA. Seven individuals were excluded because they had poor preoperative quality computed tomography scans and/or artifacts that impeded image segmentation and extraction of AAA geometric indices. The aortic fragments were subjected to uniaxial biomechanical destructive tests to obtain the following data: maximum load, failure stress, failure tension, failure strain energy, strain, and fragment thickness. In the same patients, preoperative computed tomography scans were performed with the extraction of 26 geometric indices, subdivided into 9 1-dimensional indices, 6 2-dimensional indices, and 11 3-dimensional indices. Data were subjected to statistical analysis using SPSS version 28. RESULTS Comparing ruptured and unruptured AAA, no statistical difference was observed between the biomechanical and geometric parameters. The fragment thickness of the ruptured AAA was lower than that of the unruptured AAA (P < 0.05). By comparing tomographic geometric indices and biomechanical parameters of the aortic fragments using Pearson's coefficient, positive and linear correlations (P < 0.05) were observed between the geometric variable maximum diameter (Dmax) of the AAA with maximum load (r = 0.408), failure tension (r = 0.372), and failure stress (r = 0.360). Positive and linear correlations were also observed between the variable diameter/height ratio (DHr) and the maximum load (r = 0.360), failure tension (r = 0.354), and failure stress (r = 0.289). The geometric variable DHr was dependent and correlated with Dmax. Simple regression analysis showed that R2 varied between 8.3% and 16.7%, and all models were significant (P < 0.05). CONCLUSIONS Dmax and DHr were linearly and positively correlated with the resistance parameters (maximum load, failure tension, and failure stress) of the AAA fragments. The DHr variable is dependent and correlated with Dmax. There was no correlation between the other geometric indices and the biomechanical parameters of the AAA wall. The asymmetries did not globally influence the biomechanics of AAA wall; however, they may influence regionally. Larger AAAs were stronger than smaller ones. Therefore, such findings may point toward Dmax is still the main geometric parameter, which influences the anterior wall, and possibly globally in the AAA.
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Affiliation(s)
- Bruno Donegá Constantin
- Department of Vascular and Endovascular Surgery, Medical School Hospital, University of Sao Paulo (HC-FMUSP), Sao Paulo, SP, Brazil.
| | - Erasmo Simão da Silva
- Department of Vascular and Endovascular Surgery, Medical School Hospital, University of Sao Paulo (HC-FMUSP), Sao Paulo, SP, Brazil
| | - Simon Lessard
- Université de Montréal, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Claude Kauffman
- Université de Montréal, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Gilles Soulez
- Université de Montréal, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
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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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Qiao Y, Luo K, Fan J. Heat transfer mechanism in idealized healthy and diseased aortas using fluid-structure interaction method. Biomech Model Mechanobiol 2023; 22:1953-1964. [PMID: 37481471 DOI: 10.1007/s10237-023-01745-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 07/06/2023] [Indexed: 07/24/2023]
Abstract
The heat transfer mechanism inside the human aorta may be related to the physiological function and lesion formation of the aortic wall. The objective of this study was to acquire the temperature distribution in the three-dimensional idealized aorta. An idealized healthy aortic geometry and three representative diseased aortas: aortic aneurysm, coarctation of the aorta, and aortic dissection were constructed. Advanced fluid-structure interaction (FSI) computational framework was applied to predict the aortic temperature distribution. The movement of the aortic root due to the heartbeat was also considered. The displacement distribution of the aortic vessel wall was consistent with clinical observation. The lesser curvature of the aortic arch, aneurysm body, coarctation region, and false lumen were all exposed to relatively high temperatures (over 310.006 K). We found that the rigid wall assumption slightly underestimated the magnitude of the whole aortic wall-averaged temperature while the changing trend and local temperature were like the results of the FSI method. Besides, the wall-averaged temperature would increase and the temperature inflection point would advance when the aortic vessel wall was loaded with a high heat flux. This pilot study revealed the aortic heat transfer mechanism and temperature distribution, and the findings may help to understand the physiological characteristics of the aortic vessel wall.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, China.
- Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China.
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, China
- Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China
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8
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Dalbosco M, Terzano M, Carniel TA, Fancello EA, Holzapfel GA. A two-scale numerical study on the mechanobiology of abdominal aortic aneurysms. J R Soc Interface 2023; 20:20230472. [PMID: 37907092 PMCID: PMC10618057 DOI: 10.1098/rsif.2023.0472] [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: 08/14/2023] [Accepted: 10/11/2023] [Indexed: 11/02/2023] Open
Abstract
Abdominal aortic aneurysms (AAAs) are a serious condition whose pathophysiology is related to phenomena occurring at different length scales. To gain a better understanding of the disease, this work presents a multi-scale computational study that correlates AAA progression with microstructural and mechanical alterations in the tissue. Macro-scale geometries of a healthy aorta and idealized aneurysms with increasing diameter are developed on the basis of existing experimental data and subjected to physiological boundary conditions. Subsequently, microscopic representative volume elements of the abluminal side of each macro-model are employed to analyse the local kinematics at the cellular scale. The results suggest that the formation of the aneurysm disrupts the micromechanics of healthy tissue, which could trigger collagen growth and remodelling by mechanosensing cells. The resulting changes to the macro-mechanics and microstructure of the tissue seem to establish a new homeostatic state at the cellular scale, at least for the diameter range investigated.
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Affiliation(s)
- Misael Dalbosco
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
- GRANTE—Department of Mechanical Engineering, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Michele Terzano
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
| | - Thiago A. Carniel
- Polytechnic School, Community University of Chapecó Region, Chapecó, Santa Catarina, Brazil
- Graduate Program in Health Sciences, Community University of Chapecó Region, Chapecó, Santa Catarina, Brazil
| | - Eduardo A. Fancello
- GRANTE—Department of Mechanical Engineering, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
- LEBm—University Hospital, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Gerhard A. Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
- Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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9
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Luan J, Qiao Y, Mao L, Fan J, Zhu T, Luo K. The role of aorta distal to stent in the occurrence of distal stent graft-induced new entry tear: A computational fluid dynamics and morphological study. Comput Biol Med 2023; 166:107554. [PMID: 37839217 DOI: 10.1016/j.compbiomed.2023.107554] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 09/04/2023] [Accepted: 09/28/2023] [Indexed: 10/17/2023]
Abstract
Distal stent graft-induced new entry tear (dSINE) is an important complication of thoracic endovascular aortic repair (TEVAR) for the treatment of type B aortic dissection (TBAD). This study aims to explore whether the aorta distal to the stent plays an important role in the occurrence of dSINE. Sixty-nine patient-specific geometrical models of twenty-three enrolled patients were reconstructed from preoperative, postoperative, and predSINE computed tomography scans. Computational fluid dynamics (CFD) simulations were performed to calculate the von Mises stress in the CFD group. Meanwhile, morphological measurements were performed in all patients, including measurements of the inverted pyramid index at different follow-up time points and the postoperative true lumen volume change rate. In the CFD study, the time-averaged von Mises stress of the true lumen distal to the stent in dSINE patients was significantly higher than that in the CFD controls (20.42 kPa vs. 15.47 kPa). In the morphological study, a special aortic plane (plane A) with an extremely small area distal to the stent was observed in dSINE patients, which resulted in an inverted pyramid structure in the true lumen distal to the stent. This structure in dSINE patients became increasingly obvious during the follow-up period and finally reached the maximum value before dSINE occurred (mean, 3.91 vs. 1.23). At the same time, enlargement of the true lumen distal to the stent occurs before dSINE, manifesting as a continuous increase in the true lumen volume (mean, 0.70 vs. 013). A new theory of what causes dSINE to occur has been proposed: the inverted pyramid structure of the true lumen distal to the stent caused an increase in the von Mises stress in this region and aortic enlargement, which ultimately led to the occurrence of dSINE.
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Affiliation(s)
- Jingyang Luan
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Le Mao
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China; Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China; Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China.
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10
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Raj M K, Priyadarshani J, Karan P, Bandyopadhyay S, Bhattacharya S, Chakraborty S. Bio-inspired microfluidics: A review. BIOMICROFLUIDICS 2023; 17:051503. [PMID: 37781135 PMCID: PMC10539033 DOI: 10.1063/5.0161809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/01/2023] [Indexed: 10/03/2023]
Abstract
Biomicrofluidics, a subdomain of microfluidics, has been inspired by several ideas from nature. However, while the basic inspiration for the same may be drawn from the living world, the translation of all relevant essential functionalities to an artificially engineered framework does not remain trivial. Here, we review the recent progress in bio-inspired microfluidic systems via harnessing the integration of experimental and simulation tools delving into the interface of engineering and biology. Development of "on-chip" technologies as well as their multifarious applications is subsequently discussed, accompanying the relevant advancements in materials and fabrication technology. Pointers toward new directions in research, including an amalgamated fusion of data-driven modeling (such as artificial intelligence and machine learning) and physics-based paradigm, to come up with a human physiological replica on a synthetic bio-chip with due accounting of personalized features, are suggested. These are likely to facilitate physiologically replicating disease modeling on an artificially engineered biochip as well as advance drug development and screening in an expedited route with the minimization of animal and human trials.
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Affiliation(s)
- Kiran Raj M
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036, India
| | - Jyotsana Priyadarshani
- Department of Mechanical Engineering, Biomechanics Section (BMe), KU Leuven, Celestijnenlaan 300, 3001 Louvain, Belgium
| | - Pratyaksh Karan
- Géosciences Rennes Univ Rennes, CNRS, Géosciences Rennes, UMR 6118, 35000 Rennes, France
| | - Saumyadwip Bandyopadhyay
- Advanced Technology Development Centre, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
| | - Soumya Bhattacharya
- Achira Labs Private Limited, 66b, 13th Cross Rd., Dollar Layout, 3–Phase, JP Nagar, Bangalore, Karnataka 560078, India
| | - Suman Chakraborty
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India
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11
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Wang X, Carpenter HJ, Ghayesh MH, Kotousov A, Zander AC, Amabili M, Psaltis PJ. A review on the biomechanical behaviour of the aorta. J Mech Behav Biomed Mater 2023; 144:105922. [PMID: 37320894 DOI: 10.1016/j.jmbbm.2023.105922] [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: 03/06/2023] [Revised: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 06/17/2023]
Abstract
Large aortic aneurysm and acute and chronic aortic dissection are pathologies of the aorta requiring surgery. Recent advances in medical intervention have improved patient outcomes; however, a clear understanding of the mechanisms leading to aortic failure and, hence, a better understanding of failure risk, is still missing. Biomechanical analysis of the aorta could provide insights into the development and progression of aortic abnormalities, giving clinicians a powerful tool in risk stratification. The complexity of the aortic system presents significant challenges for a biomechanical study and requires various approaches to analyse the aorta. To address this, here we present a holistic review of the biomechanical studies of the aorta by categorising articles into four broad approaches, namely theoretical, in vivo, experimental and combined investigations. Experimental studies that focus on identifying mechanical properties of the aortic tissue are also included. By reviewing the literature and discussing drawbacks, limitations and future challenges in each area, we hope to present a more complete picture of the state-of-the-art of aortic biomechanics to stimulate research on critical topics. Combining experimental modalities and computational approaches could lead to more comprehensive results in risk prediction for the aortic system.
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Affiliation(s)
- Xiaochen Wang
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Harry J Carpenter
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Mergen H Ghayesh
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Andrei Kotousov
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Anthony C Zander
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Marco Amabili
- Department of Mechanical Engineering, McGill University, Montreal H3A 0C3, Canada
| | - Peter J Psaltis
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Cardiology, Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia; Vascular Research Centre, Heart Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, South Australia 5000, Australia
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12
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Forneris A, Beddoes R, Benovoy M, Faris P, Moore RD, Di Martino ES. AI-powered assessment of biomarkers for growth prediction of abdominal aortic aneurysms. JVS Vasc Sci 2023; 4:100119. [PMID: 37662586 PMCID: PMC10470267 DOI: 10.1016/j.jvssci.2023.100119] [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: 03/15/2023] [Accepted: 06/15/2023] [Indexed: 09/05/2023] Open
Abstract
Objective The purpose of this study was to employ biomechanics-based biomarkers to locally characterize abdominal aortic aneurysm (AAA) tissue and investigate their relation to local aortic growth by means of an artificial intelligence model. Methods The study focused on a population of 36 patients with AAAs undergoing serial monitoring with electrocardiogram-gated multiphase computed tomography angiography acquisitions. The geometries of the aortic lumen and wall were reconstructed from the baseline scans and used for the baseline assessment of regional aortic weakness with three functional biomarkers, time-averaged wall-shear stress, in vivo principal strain, and intra-luminal thrombus thickness. The biomarkers were encoded as regional averages on axial and circumferential sections perpendicularly to the aortic centerline. Local diametric growth was obtained as difference in diameter between baseline and follow-up at the level of each axial section. An artificial intelligence model was developed to predict accelerated aneurysmal growth with the Extra Trees algorithm used as a binary classifier where the positive class represented regions that grew more than 2.5 mm/year. Additional clinical biomarkers, such as maximum aortic diameter at baseline, were also investigated as predictors of growth. Results The area under the curve for the constructed receiver operating characteristic curve for the Extra Trees classifier showed a very good performance in predicting relevant aortic growth (area under the curve = 0.92), with the three biomechanics-based functional biomarkers being objectively selected as the main predictors of growth. Conclusions The use of features based on the functional and local characterization of the aortic tissue resulted in a superior performance in terms of growth prediction when compared with models based on geometrical assessments. With rapid growth linked to increasing risk for patients with AAAs, the ability to access functional information related to tissue weakening and disease progression at baseline has the potential to support early clinical decisions and improve disease management.
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Affiliation(s)
- Arianna Forneris
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
- R&D Department, ViTAA Medical Solutions, Montreal, QC, Canada
| | - Richard Beddoes
- Product Development Department, ViTAA Medical Solutions, Montreal, QC, Canada
| | - Mitchel Benovoy
- Product Development Department, ViTAA Medical Solutions, Montreal, QC, Canada
- McGill University Health Center, Montreal, QC, Canada
| | - Peter Faris
- Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Calgary, AB, Canada
| | - Randy D. Moore
- R&D Department, ViTAA Medical Solutions, Montreal, QC, Canada
- Division of Vascular Surgery, University of Calgary, Calgary, AB, Canada
| | - Elena S. Di Martino
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
- R&D Department, ViTAA Medical Solutions, Montreal, QC, Canada
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13
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Kim T, Tjahjadi NS, He X, van Herwaarden JA, Patel HJ, Burris NS, Figueroa CA. Three-Dimensional Characterization of Aortic Root Motion by Vascular Deformation Mapping. J Clin Med 2023; 12:4471. [PMID: 37445507 DOI: 10.3390/jcm12134471] [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: 06/05/2023] [Revised: 06/29/2023] [Accepted: 07/02/2023] [Indexed: 07/15/2023] Open
Abstract
The aorta is in constant motion due to the combination of cyclic loading and unloading with its mechanical coupling to the contractile left ventricle (LV) myocardium. This aortic root motion has been proposed as a marker for aortic disease progression. Aortic root motion extraction techniques have been mostly based on 2D image analysis and have thus lacked a rigorous description of the different components of aortic root motion (e.g., axial versus in-plane). In this study, we utilized a novel technique termed vascular deformation mapping (VDM(D)) to extract 3D aortic root motion from dynamic computed tomography angiography images. Aortic root displacement (axial and in-plane), area ratio and distensibility, axial tilt, aortic rotation, and LV/Ao angles were extracted and compared for four different subject groups: non-aneurysmal, TAA, Marfan, and repair. The repair group showed smaller aortic root displacement, aortic rotation, and distensibility than the other groups. The repair group was also the only group that showed a larger relative in-plane displacement than relative axial displacement. The Marfan group showed the largest heterogeneity in aortic root displacement, distensibility, and age. The non-aneurysmal group showed a negative correlation between age and distensibility, consistent with previous studies. Our results revealed a strong positive correlation between LV/Ao angle and relative axial displacement and a strong negative correlation between LV/Ao angle and relative in-plane displacement. VDM(D)-derived 3D aortic root motion can be used in future studies to define improved boundary conditions for aortic wall stress analysis.
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Affiliation(s)
- Taeouk Kim
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nic S Tjahjadi
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xuehuan He
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - J A van Herwaarden
- Department of Vascular Surgery, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Himanshu J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicholas S Burris
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
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14
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Arslan AC, Salman HE. Effect of Intraluminal Thrombus Burden on the Risk of Abdominal Aortic Aneurysm Rupture. J Cardiovasc Dev Dis 2023; 10:233. [PMID: 37367398 DOI: 10.3390/jcdd10060233] [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: 04/25/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
Abdominal aortic aneurysm (AAA) is a critical health disorder, where the abdominal aorta dilates more than 50% of its normal diameter. Enlargement in abdominal aorta alters the hemodynamics and flow-induced forces on the AAA wall. Depending on the flow conditions, the hemodynamic forces on the wall may result in excessive mechanical stresses that lead to AAA rupture. The risk of rupture can be predicted using advanced computational techniques such as computational fluid dynamics (CFD) and fluid-structure interaction (FSI). For a reliable rupture risk assessment, formation of intraluminal thrombus (ILT) and uncertainty in arterial material properties should be taken into account, mainly due to the patient-specific differences and unknowns in AAAs. In this study, AAA models are computationally investigated by performing CFD simulations combined with FSI analysis. Various levels of ILT burdens are artificially generated in a realistic AAA geometry, and the peak effective stresses are evaluated to elucidate the effect of material models and ILT formation. The results indicate that increasing the ILT burden leads to lowered effective stresses on the AAA wall. The material properties of the artery and ILT are also effective on the stresses; however, these effects are limited compared to the effect of ILT volume in the AAA sac.
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Affiliation(s)
- Aykut Can Arslan
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara 06530, Turkey
| | - Huseyin Enes Salman
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara 06530, Turkey
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15
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Peng C, He W, Huang X, Ma J, Yuan T, Shi Y, Wang S. The study on the impact of AAA wall motion on the hemodynamics based on 4D CT image data. Front Bioeng Biotechnol 2023; 11:1103905. [PMID: 37064230 PMCID: PMC10098133 DOI: 10.3389/fbioe.2023.1103905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/15/2023] [Indexed: 04/03/2023] Open
Abstract
Purpose: To analyze the effect of the physiological deformation of the vessel wall on the hemodynamics in the abdominal aortic aneurysm (AAA), this paper compared the hemodynamics in AAA based on the moving boundary (MB) simulation and the rigid wall (RW) simulation.Method: Patient-specific models were reconstructed to generate mesh based on four-dimensional computed tomography angiography (4D CT) data. The dynamic mesh technique was used to achieve deformation of the vessel wall, surface mesh and volume mesh of the fluid domain were successively remeshed at each time step. Besides, another rigid wall simulation was performed. Hemodynamics obtained from these two simulations were compared.Results: Flow field and wall shear stress (WSS) distribution are similar. When using the moving boundary method (MBM), mean time-averaged wall shear stress (TAWSS) is lower, mean oscillatory shear index (OSI) and mean relative residence time (RRT) are higher. When using the 10th and 20th percentile values for TAWSS and 80th and 90th percentile values for RRT, the ratios of areas with low TAWSS, high OSI and high RRT to the entire vessel wall are higher than those assuming the vessel as rigid. In addition, one overlapping region of low TAWSS, high OSI and high RRT by using the MBM is consistent with the location of thrombus obtained from the follow-up imaging data.Conclusion: The hemodynamics results by using the MBM reflect a higher blood retention effect. This paper presents a potential tool to assess the risk of intraluminal thrombus (ILT) formation based on the MBM.
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Affiliation(s)
- Chen Peng
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Wei He
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xingsheng Huang
- Shenzhen Raysight Intelligent Medical Technology Corporation, Shenzhen, Guangdong, China
| | - Jun Ma
- Shenzhen Raysight Intelligent Medical Technology Corporation, Shenzhen, Guangdong, China
| | - Tong Yuan
- Department of Vascular Surgery, Zhongshan Hospital, 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
- *Correspondence: Yun Shi, ; Shengzhang Wang,
| | - 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
- *Correspondence: Yun Shi, ; Shengzhang Wang,
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16
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Mutlu O, Salman HE, Al-Thani H, El-Menyar A, Qidwai UA, Yalcin HC. How does hemodynamics affect rupture tissue mechanics in abdominal aortic aneurysm: Focus on wall shear stress derived parameters, time-averaged wall shear stress, oscillatory shear index, endothelial cell activation potential, and relative residence time. Comput Biol Med 2023; 154:106609. [PMID: 36724610 DOI: 10.1016/j.compbiomed.2023.106609] [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: 10/06/2022] [Revised: 01/19/2023] [Accepted: 01/22/2023] [Indexed: 01/24/2023]
Abstract
An abdominal aortic aneurysm (AAA) is a critical health condition with a risk of rupture, where the diameter of the aorta enlarges more than 50% of its normal diameter. The incidence rate of AAA has increased worldwide. Currently, about three out of every 100,000 people have aortic diseases. The diameter and geometry of AAAs influence the hemodynamic forces exerted on the arterial wall. Therefore, a reliable assessment of hemodynamics is crucial for predicting the rupture risk. Wall shear stress (WSS) is an important metric to define the level of the frictional force on the AAA wall. Excessive levels of WSS deteriorate the remodeling mechanism of the arteries and lead to abnormal conditions. At this point, WSS-related hemodynamic parameters, such as time-averaged WSS (TAWSS), oscillatory shear index (OSI), endothelial cell activation potential (ECAP), and relative residence time (RRT) provide important information to evaluate the shear environment on the AAA wall in detail. Calculation of these parameters is not straightforward and requires a physical understanding of what they represent. In addition, computational fluid dynamics (CFD) solvers do not readily calculate these parameters when hemodynamics is simulated. This review aims to explain the WSS-derived parameters focusing on how these represent different characteristics of disturbed hemodynamics. A representative case is presented for spatial and temporal formulation that would be useful for interested researchers for practical calculations. Finally, recent hemodynamics investigations relating WSS-related parameters with AAA rupture risk assessment are presented. This review will be useful to understand the physical representation of WSS-related parameters in cardiovascular flows and how they can be calculated practically for AAA investigations.
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Affiliation(s)
- Onur Mutlu
- Biomedical Research Center, Qatar University, Doha, Qatar
| | - Huseyin Enes Salman
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara, Turkey
| | - Hassan Al-Thani
- Department of Surgery, Trauma and Vascular Surgery, Hamad General Hospital, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Ayman El-Menyar
- Department of Surgery, Trauma and Vascular Surgery, Hamad General Hospital, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar; Clinical Medicine, Weill Cornell Medical College, Doha, Qatar
| | - Uvais Ahmed Qidwai
- Department of Computer Science Engineering, Qatar University, Doha, Qatar
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17
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Influence of Blood Compressibility on Pulse Wave Propagation Properties Based on Elastic Thin-Walled Tube Theory. PHYSICAL ACTIVITY AND HEALTH 2023. [DOI: 10.5334/paah.214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
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18
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Study of flow, Bioheat transfer and cardiac thermal pulse of aneurysm in the abdominal aortic. J Therm Biol 2023; 113:103481. [PMID: 37055109 DOI: 10.1016/j.jtherbio.2023.103481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 11/06/2022] [Accepted: 01/10/2023] [Indexed: 02/17/2023]
Abstract
Abdominal aortic aneurysms (AAA) are serious and difficult to detect conditions that can be deadly if they rupture. Infrared thermography (IRT) is a promising imaging technique that can detect abdominal aortic aneurysms more quickly and less costly than other imaging techniques. A clinical biomarker of circular thermal elevation on the midriff skin surface of AAA patient at various scenarios was expected during diagnosis using IRT scanner. However, it is important to note that thermography is not a perfect technology, and it does have some limitations, such as lack of clinical trials. There is still work to be done to improve this imaging technique and make it a more viable and accurate method in detecting abdominal aortic aneurysms. Nevertheless, thermography is currently one of the most convenient technologies in imaging, and it has the potential to detect abdominal aortic aneurysms earlier than other techniques. Cardiac thermal pulse (CTP), on the other hand, was used to examine the thermal physics of AAA. AAA had a CTP that only responded to systolic phase at regular body temperature. Whereas the AAA wall would establish thermal homeostasis with blood temperature following a quasi-linear relationship as the body experienced fever or stage-2 hypothermia. In contrast, a healthy abdominal aorta displayed a CTP that responded to the full cardiac cycle, including diastolic phase at all simulated scenarios.
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19
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Fonken J, Maas E, Nievergeld A, van Sambeek M, van de Vosse F, Lopata R. The Impact of a Limited Field-of-View on Computed Hemodynamics in Abdominal Aortic Aneurysms: Evaluating the Feasibility of Completing Ultrasound Segmentations with Parametric Geometries. Ann Biomed Eng 2023; 51:1296-1309. [PMID: 36709232 PMCID: PMC10172266 DOI: 10.1007/s10439-022-03133-6] [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: 09/21/2022] [Accepted: 12/25/2022] [Indexed: 01/30/2023]
Abstract
To improve abdominal aortic aneurysm (AAA) rupture risk assessment, a large, longitudinal study on AAA hemodynamics and biomechanics is necessary, using personalized fluid-structure interaction (FSI) modeling. 3-dimensional, time-resolved ultrasound (3D+t US) is the preferred image modality to obtain the patient-specific AAA geometry for such a study, since it is safe, affordable and provides temporal information. However, the 3D+t US field-of-view (FOV) is limited and therefore often fails to capture the inlet and aorto-iliac bifurcation geometry. In this study, a framework was developed to add parametric inlet and bifurcation geometries to the abdominal aortic aneurysm geometry by employing dataset statistics and parameters of the AAA geometry. The impact of replacing the patient-specific inlet and bifurcation geometries, acquired using computed tomography (CT) scans, by parametric geometries was evaluated by examining the differences in hemodynamics (systolic and time-averaged wall shear stress and oscillatory shear index) in the aneurysm region. The results show that the inlet geometry has a larger effect on the AAA hemodynamics (median differences of 7.5 to 18.8%) than the bifurcation geometry (median differences all below 1%). Therefore, it is not feasible to replace the patient-specific inlet geometry by a generic one. Future studies should investigate the possibilities of extending the proximal FOV of 3D+t US. However, this study did show the feasibility of adding a parametric bifurcation geometry to the aneurysm geometry. After extending the proximal FOV, the obtained framework can be used to extract AAA geometries from 3D+t US for FSI simulations, despite the absence of the bifurcation geometry.
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Affiliation(s)
- Judith Fonken
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands. .,Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
| | - Esther Maas
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - Arjet Nievergeld
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - Marc van Sambeek
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - Frans van de Vosse
- Cardiovascular Biomechanics, Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Richard Lopata
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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20
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Petuchova A, Maknickas A, Kostenko E, Stonkus R. Experimental and theoretical investigation of aortic wall tissue in tensile tests. Technol Health Care 2023; 31:2411-2421. [PMID: 37955068 DOI: 10.3233/thc-235007] [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: 11/14/2023]
Abstract
BACKGROUND Understanding the mechanical properties of aortic tissue is essential for developing numerical computation tools and assessing the risk of aortic aneurysm fractures. Tensile tests using aortic wall specimens allow for the determination of stress and strain depending on the location and direction of the sample. OBJECTIVE The aim of this study was to perform a mechanical tensile test using canine aorta samples and create a numerical model of aortic tissue tension from the processed data. METHODS Dogbone-shaped samples were dissected from canine aortic segments. The initial measurements were made at zero tension and the tensile tests were conducted at 10 mm/min until rupture. Force and stretch data were used to obtain engineering and true stress-strain curves. The true stress-strain curves were taken until the maximum strength was obtained, after which they were smoothed and fitted using a logistic function with three coefficients. These curves were then used as material mechanical properties for a numerical model of the aortic tissue tension. A simplified rectangle form was used to mimic the middle of the dogbone-shaped portion of the tissue specimen. Experimental displacement data were collected for the boundary conditions of the finite element 3D model. RESULTS The experimental data processing revealed that the logistic function described the nonlinear behaviour of the aorta soft tissue with an accuracy of 95% from the start of the tension to the media layer rupture. By applying numerical simulations, we obtained a correspondence of the load curve with an RMSE = 0.069 for the theoretical and experimental external tension data. CONCLUSION The numerical investigation confirmed that the non-linear soft tissue was validated by applying a logistic function approach to the mechanical properties of the aortic wall.
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Affiliation(s)
- Aleksandra Petuchova
- Department of Biomechanical Engineering, Faculty of Mechanics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Algirdas Maknickas
- Department of Biomechanical Engineering, Faculty of Mechanics, Vilnius Gediminas Technical University, Vilnius, Lithuania
- Laboratory of Numerical Simulation, Institute of Mechanics, Faculty of Mechanics, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Ernest Kostenko
- Department of Biomechanical Engineering, Faculty of Mechanics, Vilnius Gediminas Technical University, Vilnius, Lithuania
- Veterinary Department, Faculty of Agrotechnology, Vilnius College, Vilnius, Lithuania
| | - Rimantas Stonkus
- Department of Mechatronics, Robotics and Digital Manufacturing, Vilnius Gediminas Technical University, Vilnius, Lithuania
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21
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Ng E, Looi LJC. Numerical analysis of biothermal-fluids and cardiac thermal pulse of abdominal aortic aneurysm. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:10213-10251. [PMID: 36031992 DOI: 10.3934/mbe.2022479] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Abdominal aortic aneurysms are serious and difficult to detect, conditions can be deadly if they rupture. In this study, the heat transfer and flow physics of Abdominal Aortic Aneurysm (AAA) were discussed and associated with cardiac cycle to illustrate the cardiac thermal pulse (CTP) of AAA. A CTP and infrared thermography (IRT) evaluation-based on AAA and abdomen skin surface detection method was proposed, respectively. Infrared thermography (IRT) is a promising imaging technique that may detect AAA quicker and cheaper than other imaging techniques (as biomarker). From CFD rigid-wall and FSI Analysis, the transient bioheat transfer effect resulted in a distinct thermal signature (circular thermal elevation) on the temperature profile of midriff skin surface, at both regular body temperature and supine position, under normal clinical temperature. However, it is important to note that thermography is not a perfect technology, and it does have some limitations, such as lack of clinical trials. There is still work to be done to improve this imaging technique and make it a more viable and accurate method for detecting abdominal aortic aneurysms. However, thermography is currently one of the most convenient technologies in this field, and it has the potential to detect abdominal aortic aneurysms earlier than other techniques. CTP, on the other hand, was used to examine the thermal physics of AAA. In CFD rigid-wall Analysis, AAA had a CTP that only responded to systolic phase at regular body temperature. In contrast, a healthy abdominal aorta displayed a CTP that responded to the full cardiac cycle, including diastolic phase at all simulated cases. Besides, the findings from FSI Analysis suggest the influence of numerical simulation techniques on the prediction of thermal physics behaviours of AAA and abdominal skin surface. Lastly, this study correlated the relationship between natural convective heat transfer coefficient with AAA and provided reference for potential clinical diagnostic using IRT in clinical implications.
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Affiliation(s)
- Eyk Ng
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - Leonard Jun Cong Looi
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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22
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Kronborg J, Svelander F, Eriksson-Lidbrink S, Lindström L, Homs-Pons C, Lucor D, Hoffman J. Computational Analysis of Flow Structures in Turbulent Ventricular Blood Flow Associated With Mitral Valve Intervention. Front Physiol 2022; 13:806534. [PMID: 35846019 PMCID: PMC9280136 DOI: 10.3389/fphys.2022.806534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
Cardiac disease and clinical intervention may both lead to an increased risk for thrombosis events due to a modified blood flow in the heart, and thereby a change in the mechanical stimuli of blood cells passing through the chambers of the heart. Specifically, the degree of platelet activation is influenced by the level and type of mechanical stresses in the blood flow. In this article we analyze the blood flow in the left ventricle of the heart through a computational model constructed from patient-specific data. The blood flow in the ventricle is modelled by the Navier-Stokes equations, and the flow through the mitral valve by a parameterized model which represents the projected opening of the valve. A finite element method is used to solve the equations, from which a simulation of the velocity and pressure of the blood flow is constructed. The intraventricular blood flow is complex, in particular in diastole when the inflow jet from the atrium breaks down into turbulent flow on a range of scales. A triple decomposition of the velocity gradient tensor is then used to distinguish between rigid body rotational flow, irrotational straining flow, and shear flow. The triple decomposition enables the separation of three fundamentally different flow structures, that each generates a distinct type of mechanical stimulus on the blood cells in the flow. We compare the results in a simulation where a mitral valve clip intervention is modelled, which leads to a significant modification of the intraventricular flow. Further, we perform a sensitivity study of the results with respect to the positioning of the clip. It was found that the shear in the simulation cases treated with clips increased more compared to the untreated case than the rotation and strain did. A decrease in valve opening area of 64% in one of the cases led to a 90% increase in rotation and strain, but a 150% increase in shear. The computational analysis opens up for improvements in models of shear-induced platelet activation, by offering an algorithm to distinguish shear from other modalities in intraventricular blood flow.
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Affiliation(s)
- Joel Kronborg
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
- *Correspondence: Joel Kronborg,
| | - Frida Svelander
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Samuel Eriksson-Lidbrink
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ludvig Lindström
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Carme Homs-Pons
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Didier Lucor
- Laboratoire Interdisciplinaire des Sciences du Numérique (LISN), CNRS, Université Paris-Saclay, Orsay, France
| | - Johan Hoffman
- Department of Computational Science and Technology, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
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23
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Qiao Y, Luo K, Fan J. Component quantification of aortic blood flow energy loss using computational fluid-structure interaction hemodynamics. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106826. [PMID: 35526507 DOI: 10.1016/j.cmpb.2022.106826] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVES The aorta serves as the main tube of the human blood circulation system. Energy loss (EL) occurs when blood flows through the aorta and there may be a potential correlation between EL and aortic diseases. However, the components of blood flow EL are still not fully understood. This study aims to quantitatively reveal the EL components in healthy and diseased aortas. METHODS We construct an idealized healthy aorta and three idealized representative diseased aortas: aortic aneurysm, coarctation of the aorta, and aortic dissection. Computational hemodynamic studies are carried out by using the fluid-structure interaction simulation framework. RESULTS Four kinds of EL components: viscous friction, turbulence dissipation, wall deformation, and local lesion are firstly acquired in healthy and diseased aortas based on the high-resolution blood flow information. Viscous friction contributes most to the EL (45.69%-57.22%). EL caused by the deformation of the aortic wall ranks second (15.18%-33.12%). The proportions of turbulence dissipation and local lesion depend on individual geometric characteristics. Besides, the buffering efficiency of the healthy and diseased aorta is about 80%. CONCLUSIONS This study quantitatively reports the components of blood flow EL in healthy and diseased aortas, the finding may provide novel insights into the pathogenesis of aortic diseases.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China; Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China.
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China; Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China
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24
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Wen J, Yan T, Su Z, Huang H, Gao Q, Chen X, Wong KKL, Peng L. Risk evaluation of type B aortic dissection based on WSS-based indicators distribution in different types of aortic arch. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106872. [PMID: 35594583 DOI: 10.1016/j.cmpb.2022.106872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/26/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE The underlying mechanism of aortic dissection (AD) remains unclear and the onset of AD is still unpredictable. Although clinical study with statistical analysis has reported that type III aortic arch may have strong correlation with type B AD (TBD), the effects of different arch types on the wall shear stress (WSS) have not been clarified. METHODS As a complementary work, this study numerically investigated the distribution of five WSS-based indicators in thirty aortic arches without AD, which were classified into three groups based on the arch types. RESULTS The distribution of most WSS indicators, such as time averaged WSS (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT) had no significant difference among different types of aortic arches (P>0.05). However, a multidirectional WSS index, namely CFI, was found its maximum value was positively correlated with type III aortic arch in proximal descending aorta (p<0.001, r = 0.65). CONCLUSIONS It can be concluded that the enhancement or oscillation of WSS may not be the main reason of TBD is prevalence in type III arches, while the multidirectional WSS distribution may be an important factor. It can be further referred that the CFI may have a potential to predict the onset of TBD.
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Affiliation(s)
- Jun Wen
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Tingli Yan
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhiqiao Su
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Haodi Huang
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Qi Gao
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Xiaoyi Chen
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Kelvin K L Wong
- School of Computer Science and Engineering, Central South University, Changsha 410000, China.
| | - Liqing Peng
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China.
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25
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Numerical investigation of abdominal aortic aneurysm hemodynamics using the reduced unified continuum formulation for vascular fluid-structure interaction. FORCES IN MECHANICS 2022. [DOI: 10.1016/j.finmec.2022.100089] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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26
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Philip NT, Patnaik BSV, Sudhir BJ. Hemodynamic simulation of abdominal aortic aneurysm on idealised models: Investigation of stress parameters during disease progression. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 213:106508. [PMID: 34800807 DOI: 10.1016/j.cmpb.2021.106508] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND OBJECTIVE Analysis and prediction of rupture risk of abdominal aortic aneurysms (AAA) facilitates planning for surgical interventions and assessment of plausible treatment modalities. Present approach of using maximum diameter criterion, is giving way to hemodynamic and bio-mechanical based predictors in conjunction with Computational fluid dynamic (CFD) simulations. Detailed studies on hemodynamic and bio-mechanical parameters at the stage of maximum growth/rupture is of practical importance to the clinical community. However, understanding the changes in these parameters at different stages of growth, will be useful for clinicians, in planning routine monitoring to reduce the risk of sudden rupture. This is particularly useful in medical resource starved nations. Present study investigates the hemodynamic and bio-mechanical changes occurring during the growth stages of aortic aneurysms using fluid structure interaction (FSI) studies. METHOD Six idealized fusiform aneurysm models spanning high (shorter) and low (longer) values of the shape index (DHr), have been analysed at three different stages of growth viz, a Dmax of 3.5cm, 4.25cm, 5cm. Pulsatile Newtonian blood flow, passing through an elastic arterial vessel wall with uniform thickness is assumed. Two-way coupled fluid structure interaction have been employed for the numerical simulation of blood flow dynamics and arterial wall mechanics. RESULTS Wall shear stress (WSS) parameters and vonmises stress indicators, co-relating rupture and thrombus formation, have been extracted and reported, at each growth stage. When the aneurysm progresses in diameter, the areas recording abnormally low TAWSS, as well as areas of high/low OSI were found to increase at different rates for shorter and longer aneurysms. Moreover, drastic increase in the maximum wall stresses (MWS) and wall displacement were observed as the aneurysm approached the critical diameter. CONCLUSION Hemodynamic predictors were found to be highly dependent on the shape index (DHr), when the aneurysm was small, whereas significant influence of DHr on the wall stresses happens, as the aneurysm approaches the critical diameter. Inconsistent variation of these indicators exhibited by shorter aneurysms (high DHr) at different growth stages, demands routine monitoring (using scans), of such aneurysms, to prevent unexpected rupture.
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Affiliation(s)
- Nimmy Thankom Philip
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, 600036, India
| | - B S V Patnaik
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, 600036, India
| | - B J Sudhir
- Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, 695011, Kerala.
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27
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Cury LFM, Maso Talou GD, Younes-Ibrahim M, Blanco PJ. Parallel generation of extensive vascular networks with application to an archetypal human kidney model. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210973. [PMID: 34966553 PMCID: PMC8633801 DOI: 10.1098/rsos.210973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 10/28/2021] [Indexed: 05/25/2023]
Abstract
Given the relevance of the inextricable coupling between microcirculation and physiology, and the relation to organ function and disease progression, the construction of synthetic vascular networks for mathematical modelling and computer simulation is becoming an increasingly broad field of research. Building vascular networks that mimic in vivo morphometry is feasible through algorithms such as constrained constructive optimization (CCO) and variations. Nevertheless, these methods are limited by the maximum number of vessels to be generated due to the whole network update required at each vessel addition. In this work, we propose a CCO-based approach endowed with a domain decomposition strategy to concurrently create vascular networks. The performance of this approach is evaluated by analysing the agreement with the sequentially generated networks and studying the scalability when building vascular networks up to 200 000 vascular segments. Finally, we apply our method to vascularize a highly complex geometry corresponding to the cortex of a prototypical human kidney. The technique presented in this work enables the automatic generation of extensive vascular networks, removing the limitation from previous works. Thus, we can extend vascular networks (e.g. obtained from medical images) to pre-arteriolar level, yielding patient-specific whole-organ vascular models with an unprecedented level of detail.
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Affiliation(s)
- L. F. M. Cury
- National Laboratory for Scientific Computing, LNCC/MCTI, Petrópolis, Brazil
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
| | - G. D. Maso Talou
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - M. Younes-Ibrahim
- Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro, Brazil
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
| | - P. J. Blanco
- National Laboratory for Scientific Computing, LNCC/MCTI, Petrópolis, Brazil
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
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28
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Qiao Y, Mao L, Ding Y, Zhu T, Luo K, Fan J. Fluid-structure interaction: Insights into biomechanical implications of endograft after thoracic endovascular aortic repair. Comput Biol Med 2021; 138:104882. [PMID: 34600328 DOI: 10.1016/j.compbiomed.2021.104882] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/04/2021] [Accepted: 09/19/2021] [Indexed: 10/20/2022]
Abstract
Thoracic endovascular aortic repair (TEVAR) has developed to be the most effective treatment for aortic diseases. This study aims to evaluate the biomechanical implications of the implanted endograft after TEVAR. We present a novel image-based, patient-specific, fluid-structure computational framework. The geometries of blood, endograft, and aortic wall were reconstructed based on clinical images. Patient-specific measurement data was collected to determine the parameters of the three-element Windkessel. We designed three postoperative scenarios with rigid wall assumption, blood-wall interaction, blood-endograft-wall interplay, respectively, where a two-way fluid-structure interaction (FSI) method was applied to predict the deformation of the composite stent-wall. Computational results were validated with Doppler ultrasound data. Results show that the rigid wall assumption fails to predict the waveforms of blood outflow and energy loss (EL). The complete storage and release process of blood flow energy, which consists of four phases is captured by the FSI method. The endograft implantation would weaken the buffer function of the aorta and reduce mean EL by 19.1%. The closed curve area of wall pressure and aortic volume could indicate the EL caused by the interaction between blood flow and wall deformation, which accounts for 68.8% of the total EL. Both the FSI and endograft have a slight effect on wall shear stress-related-indices. The deformability of the composite stent-wall region is remarkably limited by the endograft. Our results highlight the importance of considering the interaction between blood flow, the implanted endograft, and the aortic wall to acquire physiologically accurate hemodynamics in post-TEVAR computational studies and the deformation of the aortic wall is responsible for the major EL of the blood flow.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Le Mao
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ying Ding
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
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29
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Fonken JHC, Maas EJ, Nievergeld AHM, van Sambeek MRHM, van de Vosse FN, Lopata RGP. Ultrasound-Based Fluid-Structure Interaction Modeling of Abdominal Aortic Aneurysms Incorporating Pre-stress. Front Physiol 2021; 12:717593. [PMID: 34483971 PMCID: PMC8414835 DOI: 10.3389/fphys.2021.717593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/16/2021] [Indexed: 12/05/2022] Open
Abstract
Currently, the prediction of rupture risk in abdominal aortic aneurysms (AAAs) solely relies on maximum diameter. However, wall mechanics and hemodynamics have shown to provide better risk indicators. Patient-specific fluid-structure interaction (FSI) simulations based on a non-invasive image modality are required to establish a patient-specific risk indicator. In this study, a robust framework to execute FSI simulations based on time-resolved three-dimensional ultrasound (3D+t US) data was obtained and employed on a data set of 30 AAA patients. Furthermore, the effect of including a pre-stress estimation (PSE) to obtain the stresses present in the measured geometry was evaluated. The established workflow uses the patient-specific 3D+t US-based segmentation and brachial blood pressure as input to generate meshes and boundary conditions for the FSI simulations. The 3D+t US-based FSI framework was successfully employed on an extensive set of AAA patient data. Omitting the pre-stress results in increased displacements, decreased wall stresses, and deviating time-averaged wall shear stress and oscillatory shear index patterns. These results underline the importance of incorporating pre-stress in FSI simulations. After validation, the presented framework provides an important tool for personalized modeling and longitudinal studies on AAA growth and rupture risk.
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Affiliation(s)
- Judith H. C. Fonken
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, Netherlands
| | - Esther J. Maas
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, Netherlands
| | - Arjet H. M. Nievergeld
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, Netherlands
| | - Marc R. H. M. van Sambeek
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
- Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, Netherlands
| | - Frans N. van de Vosse
- Cardiovascular Biomechanics, Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Richard G. P. Lopata
- Photoacoustics & Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomechanical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
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30
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Marino M, Vairo G, Wriggers P. Mechano-chemo-biological Computational Models for Arteries in Health, Disease and Healing: From Tissue Remodelling to Drug-eluting Devices. Curr Pharm Des 2021; 27:1904-1917. [PMID: 32723253 DOI: 10.2174/1381612826666200728145752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/14/2020] [Indexed: 11/22/2022]
Abstract
This review aims to highlight urgent priorities for the computational biomechanics community in the framework of mechano-chemo-biological models. Recent approaches, promising directions and open challenges on the computational modelling of arterial tissues in health and disease are introduced and investigated, together with in silico approaches for the analysis of drug-eluting stents that promote pharmacological-induced healing. The paper addresses a number of chemo-biological phenomena that are generally neglected in biomechanical engineering models but are most likely instrumental for the onset and the progression of arterial diseases. An interdisciplinary effort is thus encouraged for providing the tools for an effective in silico insight into medical problems. An integrated mechano-chemo-biological perspective is believed to be a fundamental missing piece for crossing the bridge between computational engineering and life sciences, and for bringing computational biomechanics into medical research and clinical practice.
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Affiliation(s)
- Michele Marino
- Institute of Continuum Mechanics, Leibniz Universität Hannover, An der Universität 1, 30823 Garbsen, Germany
| | - Giuseppe Vairo
- Department of Civil Engineering and Computer Science, University of Rome "Tor Vergata" via del Politecnico 1, 00133 Rome, Italy
| | - Peter Wriggers
- Institute of Continuum Mechanics, Leibniz Universität Hannover, An der Universität 1, 30823 Garbsen, Germany
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31
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Ashraf F, Ambreen T, Park CW, Kim DI. Comparative evaluation of ballet-type and conventional stent graft configurations for endovascular aneurysm repair: A CFD analysis. Clin Hemorheol Microcirc 2021; 78:1-27. [PMID: 33459700 PMCID: PMC8293652 DOI: 10.3233/ch-200996] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE: Cross limb stent graft (SG) configuration technique for endovascular aneurysm repair (EVAR) is employed for splayed aortic bifurcations to avoid device kinking and smoothen cannulation. The present study investigates three types of stent graft (SG) configurations for endovascular aneurysm repair (EVAR) in abdominal aortic aneurysm. A computational fluid dynamic analysis was performed on the pulsatile non-Newtonian flow characteristics in three ideally modeled geometries of abdominal aortic (AA) SG configurations. METHODS: The three planar and crosslimb SG configurations were ideally modeled, namely, top-down nonballet-type, top-down ballet-type, and bottom-up nonballet-type configurations. In top-down SG configuration, most of the device is deployed in the main body in the vicinity of renal artery and the limbs are extended to the iliac artery. While in the bottom-up configuration, some of the SG device is deployed in the main body, the limbs are deployed in aortic bifurcation, and the extra stent graft of the main body is extended to the proximal aorta until the below of the renal artery. The effects of non-Newtonian pulsatile flow on the wall stresses and flow patterns of the three models were investigated and compared. Moreover, the average wall shear stress (AWSS), oscillatory shear stress index (OSI), absolute helicity, pressure distribution, graft displacement and flow visualization plots were analyzed. RESULTS: The top-down ballet-type showed less branch blockage effect than the top-down nonballet-type models. Furthermore, the top-down ballet-type configuration showed an increased tendency to sustain high WSS and higher helicity characteristics than that of the bottom-up and top-down non-ballet type configurations. However, displacement forces of the top-down ballet-type configuration were 40% and 9.6% higher than those of the bottom-up and top-down nonballet-type configurations, respectively. CONCLUSIONS: Some complications such as graft tearing, thrombus formation, limb disconnection during long term follow up periods might be relevant to hemodynamic characteristics according to the configurations of EVAR. Hence, the reported data required to be validated with the clinical results.
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Affiliation(s)
- Fahmida Ashraf
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Tehmina Ambreen
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Cheol Woo Park
- School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea
| | - Dong-Ik Kim
- Division of Vascular Surgery, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, South Korea
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32
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Nannini G, Caimi A, Palumbo MC, Saitta S, Girardi LN, Gaudino M, Roman MJ, Weinsaft JW, Redaelli A. Aortic hemodynamics assessment prior and after valve sparing reconstruction: A patient-specific 4D flow-based FSI model. Comput Biol Med 2021; 135:104581. [PMID: 34174756 DOI: 10.1016/j.compbiomed.2021.104581] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/09/2021] [Accepted: 06/13/2021] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Valve-sparing root replacement (VSRR) of the ascending aorta is a life-saving procedure for the treatment of aortic aneurysms, but patients remain at risk for post-operative events involving the downstream native aorta, the mechanism for which is uncertain. It is possible that proximal graft replacement of the ascending aorta induces hemodynamics alterations in the descending aorta, which could trigger adverse events. Herein, we present a fluid-structure interaction (FSI) protocol, based on patient-specific geometry and boundary conditions, to assess impact of proximal aortic grafts on downstream aortic hemodynamics and distensibility. METHODS Cardiac magnetic resonance (CMR), including MRA, cine-CMR and 4D flow sequences, was performed prior and after VSRR on one subject. Central blood pressure was non-invasively acquired at the time of the CMR: data were used to reconstruct the pre- and post-VSRR model and derive patient-specific boundary conditions for the FSI and a computational fluid dynamic (CFD) analysis with the same settings. Results were validated comparing the predicted velocity field against 4D flow dataset, over four landmarks along the aorta, and the predicted distensibility against the cine-CMR derived value. RESULTS Instantaneous velocity magnitudes extracted from 4D flow and FSI were similar (p > 0.05), while CFD-predicted velocity was significantly higher (p < 0.001), especially in the descending aorta of the pre-VSRR model (vmax was 73 cm/s, 76 cm/s and 99 cm/s, respectively). As measured in cine-CMR, FSI predicted an increase in descending aorta distensibility after grafting (i.e., 4.02 to 5.79 10-3 mmHg-1). In the descending aorta, the post-VSRR model showed increased velocity, aortic distensibility, stress and strain and wall shear stress. CONCLUSIONS Our Results indicate that i) the distensibility of the wall cannot be neglected, and hence the FSI method is necessary to obtain reliable results; ii) graft implantation induces alterations in the hemodynamics and biomechanics along the thoracic aorta, that may trigger adverse vessel remodeling.
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Affiliation(s)
- Guido Nannini
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy.
| | - Alessandro Caimi
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Maria Chiara Palumbo
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Simone Saitta
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Leonard N Girardi
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Mario Gaudino
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, USA
| | - Mary J Roman
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
| | - Jonathan W Weinsaft
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
| | - Alberto Redaelli
- Department of Electronics Information and Bioengineering, Politecnico di Milano, Milan, Italy
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33
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Yu P, Durgesh V, Xing T, Budwig R. Application of Proper Orthogonal Decomposition to Study Coherent Flow Structures in a Saccular Aneurysm. J Biomech Eng 2021; 143:1097187. [PMID: 33537715 DOI: 10.1115/1.4050032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Indexed: 01/30/2023]
Abstract
Aneurysms are localized expansions of weakened blood vessels that can be debilitating or fatal upon rupture. Previous studies have shown that flow in an aneurysm exhibits complex flow structures that are correlated with its inflow conditions. Therefore, the objective of this study was to demonstrate the application of proper orthogonal decomposition (POD) to study the impact of different inflow conditions on energetic flow structures and their temporal behavior in an aneurysm. To achieve this objective, experiments were performed on an idealized rigid sidewall aneurysm model. A piston pump system was used for precise inflow control, i.e., peak Reynolds number (Rep) and Womersley number (α) were varied from 50 to 270 and 2 to 5, respectively. The velocity flow field measurements at the midplane location of the idealized aneurysm model were performed using particle image velocimetry (PIV). The results demonstrate the efficacy of POD in decomposing complex data, and POD was able to capture the energetic flow structures unique to each studied inflow condition. Furthermore, the time-varying coefficient results highlighted the interplay between the coefficients and their corresponding POD modes, which in turn helped explain how POD modes impact certain flow features. The low-order reconstruction results were able to capture the flow evolution and provide information on complex flow in an aneurysm. The POD and low-order reconstruction results also indicated that vortex formation, evolution, and convection varied with an increase in α, while vortex strength and formation of secondary structures were correlated with an increase in Rep.
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Affiliation(s)
- Paulo Yu
- Mechanical Engineering, University of Idaho, Moscow, ID 83844
| | - Vibhav Durgesh
- Mechanical Engineering, University of Idaho, Moscow, ID 83844
| | - Tao Xing
- Mechanical Engineering, University of Idaho, Moscow, ID 83844
| | - Ralph Budwig
- Mechanical Engineering, University of Idaho, Boise, ID 83844
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YANG JING, YANG LIUQING, MA SHANHONG, ZHAO DEMING, QIN TAO. NUMERICAL COUPLING ANALYSIS OF THE INFLUENCE OF BLOOD FLOW ON THE MECHANICAL RESPONSE FOR LIVER. J MECH MED BIOL 2021. [DOI: 10.1142/s0219519421500184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
As an important basis for determining the state of the liver, the mechanical responses are associated with many factors, and belong to a complex coupling system. Liver tissue has significantly complicated vascular channels. The vascular diameter, vascular deflection angle and vascular depth are defined as the key characteristic parameters. The influences of these parameters on the mechanical responses were analyzed. On the basis of the real mechanical parameters, the coupled numerical model of blood vessel, blood flow and liver tissue was established. The corresponding mechanical responses are obtained by utilizing the different vascular parameters. The effects of vascular parameters on the differences among the mechanical response difference and high strain modulus were analyzed. It was found that the blood vessels in the central area could reduce the liver mechanical response. The inner diameter parameter had main influences on the regions where the stain was more than 0.1. The mechanical difference is greater with larger inner diameter. The influences of vascular depth are greatest when the vascular depth was in the intermediate value, which would increase the liver mechanical responses. With the increment of vascular deflection angle, the liver mechanical response would also increase, and exceed the mechanical response without blood vessels. The findings after analyzing the influence of vascular parameters will provide a basis for the quantitative studies on the influence of blood vessels.
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Affiliation(s)
- JING YANG
- Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou, Zhejiang Province, P. R. China
- Hubei Collaborative Innovation Center for Digitalization of Automobile Parts, Manufacturing Equipment Xiangyang, Hubei Province, P. R. China
| | - LIUQING YANG
- Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou, Zhejiang Province, P. R. China
| | - SHANHONG MA
- Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou, Zhejiang Province, P. R. China
| | - DEMING ZHAO
- Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou, Zhejiang Province, P. R. China
| | - TAO QIN
- School of Mechanical Engineering, Hubei University of Arts and Science, Xiangyang, Hubei Province, P. R. China
- Hubei Collaborative Innovation Center for Digitalization of Automobile Parts, Manufacturing Equipment Xiangyang, Hubei Province, P. R. China
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Forneris A, Kennard J, Ismaguilova A, Shepherd RD, Studer D, Bromley A, Moore RD, Rinker KD, Di Martino ES. Linking Aortic Mechanical Properties, Gene Expression and Microstructure: A New Perspective on Regional Weakening in Abdominal Aortic Aneurysms. Front Cardiovasc Med 2021; 8:631790. [PMID: 33659281 PMCID: PMC7917077 DOI: 10.3389/fcvm.2021.631790] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/15/2021] [Indexed: 11/24/2022] Open
Abstract
Background: Current clinical practice for the assessment of abdominal aortic aneurysms (AAA) is based on vessel diameter and does not account for the multifactorial, heterogeneous remodeling that results in the regional weakening of the aortic wall leading to aortic growth and rupture. The present study was conducted to determine correlations between a novel non-invasive surrogate measure of regional aortic weakening and the results from invasive analyses performed on corresponding ex vivo aortic samples. Tissue samples were evaluated to classify local wall weakening and the likelihood of further degeneration based on non-invasive indices. Methods: A combined, image-based fluid dynamic and in-vivo strain analysis approach was used to estimate the Regional Aortic Weakness (RAW) index and assess individual aortas of AAA patients prior to elective surgery. Nine patients were treated with complete aortic resection allowing the systematic collection of tissue samples that were used to determine regional aortic mechanics, microstructure and gene expression by means of mechanical testing, microscopy and transcriptomic analyses. Results: The RAW index was significantly higher for samples exhibiting lower mechanical strength (p = 0.035) and samples classified as low elastin content (p = 0.020). Samples with higher RAW index had the greatest number of genes differentially expressed compared to any constitutive metric. High RAW samples showed a decrease in gene expression for elastin and a down-regulation of pathways responsible for cell movement, reorganization of cytoskeleton, and angiogenesis. Conclusions: This work describes the first AAA index free of assumptions for material properties and accounting for patient-specific mechanical behavior in relation to aneurysm strength. Use of the RAW index captured biomechanical changes linked to the weakening of the aorta and revealed changes in microstructure and gene expression. This approach has the potential to provide an improved tool to aid clinical decision-making in the management of aortic pathology.
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Affiliation(s)
- Arianna Forneris
- Biomedical Engineering, University of Calgary, Calgary, AB, Canada.,Department of Civil Engineering, University of Calgary, Calgary, AB, Canada
| | - Jacob Kennard
- Biomedical Engineering, University of Calgary, Calgary, AB, Canada
| | | | | | - Deborah Studer
- Biomedical Engineering, University of Calgary, Calgary, AB, Canada
| | - Amy Bromley
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Randy D Moore
- Department of Surgery, University of Calgary, Calgary, AB, Canada
| | - Kristina D Rinker
- Biomedical Engineering, University of Calgary, Calgary, AB, Canada.,Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Elena S Di Martino
- Biomedical Engineering, University of Calgary, Calgary, AB, Canada.,Department of Civil Engineering, University of Calgary, Calgary, AB, Canada
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He F, Hua L, Guo T. Numerical modeling in arterial hemodynamics incorporating fluid-structure interaction and microcirculation. Theor Biol Med Model 2021; 18:6. [PMID: 33468179 PMCID: PMC7816504 DOI: 10.1186/s12976-021-00136-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 01/11/2021] [Indexed: 11/30/2022] Open
Abstract
Background The effects of arterial wall compliance on blood flow have been revealed using fluid-structure interaction in last decades. However, microcirculation is not considered in previous researches. In fact, microcirculation plays a key role in regulating blood flow. Therefore, it is very necessary to involve microcirculation in arterial hemodynamics. Objective The main purpose of the present study is to investigate how wall compliance affects the flow characteristics and to establish the comparisons of these flow variables with rigid wall when microcirculation is considered. Methods We present numerical modeling in arterial hemodynamics incorporating fluid-structure interaction and microcirculation. A novel outlet boundary condition is employed to prescribe microcirculation in an idealised model. Results The novel finding in this work is that wall compliance under the consideration of microcirculation leads to the increase of wall shear stress in contrast to rigid wall, contrary to the traditional result that wall compliance makes wall shear stress decrease when a constant or time dependent pressure is specified at an outlet. Conclusions This work provides the valuable study of hemodynamics under physiological and realistic boundary conditions and proves that wall compliance may have a positive impact on wall shear stress based on this model. This methodology in this paper could be used in real model simulations.
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Affiliation(s)
- Fan He
- Department of Mechanics, School of Science, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
| | - Lu Hua
- Thrombosis Center, National Clinical Research Center for Cardiovascular Diseases, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
| | - Tingting Guo
- Thrombosis Center, National Clinical Research Center for Cardiovascular Diseases, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
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37
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Kannojiya V, Das AK, Das PK. Simulation of Blood as Fluid: A Review From Rheological Aspects. IEEE Rev Biomed Eng 2021; 14:327-341. [DOI: 10.1109/rbme.2020.3011182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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de Lucio M, García MF, García JD, Rodríguez LER, Marcos FÁ. On the importance of tunica intima in the aging aorta: a three-layered in silico model for computing wall stresses in abdominal aortic aneurysms. Comput Methods Biomech Biomed Engin 2020; 24:467-484. [PMID: 33090043 DOI: 10.1080/10255842.2020.1836167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Layer-specific experimental data for human aortic tissue suggest that, in aged arteries and arteries with non-atherosclerotic intimal thickening, the innermost layer of the aorta increases significantly its stiffness and thickness, becoming load-bearing. However, there are very few computational studies of abdominal aortic aneurysms (AAAs) that take into account the mechanical contribution of the three layers that comprise the aneurysmal tissue. In this paper, a three-layered finite element model is proposed from the simplest uniaxial stress state to geometrically parametrized models of AAAs with different asymmetry values. Comparisons are made between a three-layered artery wall and a mono-layered intact artery, which represents the complex behavior of the aggregate adventitia-media-intima in a single layer with averaged mechanical properties. Likewise, the response of our idealized geometries is compared with similar experimental and numerical models. Finally, the mechanical contributions of adventitia, media and intima are analyzed for the three-layered aneurysms through the evaluation of the mean stress absorption percentage. Results show the relevance and necessity of considering the inclusion of tunica intima in multi-layered models of AAAs for getting accurate results in terms of peak wall stresses and displacements.
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Affiliation(s)
- Mario de Lucio
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Marcos Fernández García
- Structural Impact Laboratory (SIMLab) and Centre for Advanced Structural Analysis (CASA), Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jacobo Díaz García
- Structural Mechanics Group, School of Civil Engineering, Universidade da Coruña, A Coruña, Spain
| | | | - Francisco Álvarez Marcos
- Angiology and Vascular Surgery Department, Asturias University Central Hospital (HUCA), Oviedo, Spain
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Meng Z, Ma T, Cai Y, Liu X, Wang S, Dong Z, Fu W. Numerical modeling and simulations of type B aortic dissection treated by stent-grafts with different oversizing ratios. Artif Organs 2020; 44:1202-1210. [PMID: 32530055 DOI: 10.1111/aor.13750] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 05/13/2020] [Accepted: 06/05/2020] [Indexed: 11/28/2022]
Abstract
Retrograde type A dissection after thoracic endovascular aortic repair has been a major drawback of endovascular treatment. This study investigated the biomechanical mechanism of stent-graft-induced new lesions after implantation and analyzed the relationship between radial force and spring-back force of the stent-graft when it was implanted virtually under different oversizing ratios. Based on the computed tomography angiography images, a three-dimensional geometric model of a patient-specific aortic dissection was established. The stent was designed in CAD software and the stent-graft implantation procedure under different oversizing ratios was simulated in the finite element analysis software. Implantation simulations were performed six times for each stent-graft model under 0%, 3%, 6%, 9%, 12%, and 15% oversizing ratios and the peak stress of the aorta was compared among groups. It was observed that the peak stress of the aorta was located where the proximal bare stent interacted with aortic wall and its value was increased by 62.2% from 0% to 15% oversizing ratio. The conclusions are reached that the long-term higher stress in the aortic wall may lead to the emergence of new lesions in these areas, and the radial force plays a key role in the formation of a new entry in the real aorta model.
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Affiliation(s)
- Zhuangyuan Meng
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Tao Ma
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yunhan Cai
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Xudong Liu
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Shengzhang Wang
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
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40
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Boyd AJ. Biomechanical prediction of abdominal aortic aneurysm rupture potential. J Vasc Surg 2020; 71:627. [PMID: 32040432 DOI: 10.1016/j.jvs.2019.03.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 03/26/2019] [Indexed: 11/25/2022]
Affiliation(s)
- April J Boyd
- Department of Vascular Surgery, University of Manitoba, Winnipeg, Manitoba, Canada
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Jayendiran R, Condemi F, Campisi S, Viallon M, Croisille P, Avril S. Computational prediction of hemodynamical and biomechanical alterations induced by aneurysm dilatation in patient-specific ascending thoracic aortas. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3326. [PMID: 32087044 DOI: 10.1002/cnm.3326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 02/15/2020] [Indexed: 06/10/2023]
Abstract
The aim of the present work is to propose a robust computational framework combining computational fluid dynamics (CFD) and 4D flow MRI to predict the progressive changes in hemodynamics and wall rupture index (RPI) induced by aortic morphological evolutions in patients harboring ascending thoracic aortic aneurysms (ATAAs). An analytical equation has been proposed to predict the aneurysm progression based on age, sex, and body surface area. Parameters such as helicity, wall shear stress (WSS), time-averaged WSS, oscillatory shear index, relative residence time, and viscosity were evaluated for two patients at different stages of aneurysm growth, and compared with age-sex-matched healthy subjects. The study shows that evolution of hemodynamics and RPI, despite being very slow in ATAAs, is strongly affected by morphological alterations and, in turn could impact biomechanical factors and aortic mechanobiology. An aspect of the current work is that the patient-specific 4D MRI data sets were obtained with a follow-up of 1 year and the measured time-averaged velocity maps and flow eccentricity were compared with the CFD simulation for validation. The computational framework presented here is capable of capturing the blood flow patterns and the hemodynamic descriptors during the various stages of aneurysm growth. Further investigations will be conducted in order to verify these results on a larger cohort of patients and with long follow-up times to finally elucidate the link between deranged hemodynamics, AA geometry, and wall mechanical properties in ATAAs.
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Affiliation(s)
- Raja Jayendiran
- Mines Saint-Etienne, Université de Lyon, INSERM, U1059, SAINBIOSE, Saint-Etienne F-42023, France
| | | | - Salvatore Campisi
- Department of Cardiovascular Surgery, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Magalie Viallon
- UJM-Saint-Etienne, INSA, CNRS UMR 5520, INSERM U1206, CREATIS, Université de Lyon, Saint-Etienne, France
- Department of Radiology, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Pierre Croisille
- UJM-Saint-Etienne, INSA, CNRS UMR 5520, INSERM U1206, CREATIS, Université de Lyon, Saint-Etienne, France
- Department of Radiology, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Stéphane Avril
- Mines Saint-Etienne, Université de Lyon, INSERM, U1059, SAINBIOSE, Saint-Etienne F-42023, France
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A novel combined fluid dynamic and strain analysis approach identified abdominal aortic aneurysm rupture. JOURNAL OF VASCULAR SURGERY CASES INNOVATIONS AND TECHNIQUES 2020; 6:172-176. [PMID: 32322769 PMCID: PMC7160522 DOI: 10.1016/j.jvscit.2020.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 01/25/2020] [Indexed: 01/04/2023]
Abstract
Clinical decision-making for surgical repair of abdominal aortic aneurysms based on maximum aortic diameter presents limitations as rupture can occur below threshold for some aneurysms, whereas others are stable at large sizes. The proposed approach combines hemodynamics and geometric indices with in vivo deformation analysis to assess local weakening of the aortic wall for a case of impending rupture that was confirmed during open surgical repair. A new combined index, the Regional Rupture Potential, is introduced to help the assessment of individual aneurysms and their rupture risk, providing a rationale for clinical decisions.
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Jayendiran R, Nour B, Ruimi A. Computational analysis of Nitinol stent-graft for endovascular aortic repair (EVAR) of abdominal aortic aneurysm (AAA): Crimping, sealing and fluid-structure interaction (FSI). Int J Cardiol 2020; 304:164-171. [PMID: 31791620 DOI: 10.1016/j.ijcard.2019.11.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/20/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVES We evaluate the crimping strain, sealing stress and contact forces on a Nitinol stent deployed in the aorta during endovascular aortic (or aneurysm) repair (EVAR) procedures. Nitinol shape memory effect (SME) is used. We also study the fluid-structure interaction (FSI) of the blood flow on the stented aorta. METHODS We employ Solidworks to generate a closed-cell honeycomb stent structure used to treat abdominal aortic aneurysm (AAA). We use the commercial Abaqus/Simulia finite element (FEM) simulation package to study the displacements and stresses experienced by the stent during the crimping phase and deployment into the aortic segment. The Nitinol stent is covered with Dacron, a popular graft material. We implement our own user-material (UMAT) subroutines to model the shape memory effect (SME) of Nitinol. The effect of the stent geometry is analyzed. We use the FSI analysis in Abaqus/Simulia to understand the effect of hemodynamic loading on the stent. RESULTS Results indicate that the crimping strain increases as the stent strut spacing increases. This is also the case for the radius of curvature. Maximum strains developed on the stent during crimping are in the order of 10%. Stresses exerted by the stent needed to completely seal the aorta are found to be below the yield stress values of Nitinol (700 MPa). Wall shear stresses (WSS) on the stented aorta are close to WSS obtained on the aorta alone. CONCLUSION Using Nitinol's thermo-reactivity property as opposed to its superelasticity causes the stent-graft to deploy more gently.
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Affiliation(s)
- Raja Jayendiran
- Mechanical Engineering Program, Texas A&M University at Qatar, Doha, Qatar.
| | - Bakr Nour
- Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Annie Ruimi
- Mechanical Engineering Program, Texas A&M University at Qatar, Doha, Qatar.
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Computational Fluid Dynamics Modeling of Hemodynamic Parameters in the Human Diseased Aorta: A Systematic Review. Ann Vasc Surg 2020; 63:336-381. [DOI: 10.1016/j.avsg.2019.04.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/09/2019] [Accepted: 04/18/2019] [Indexed: 02/07/2023]
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45
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Biomechanical implications of the fenestration structure after thoracic endovascular aortic repair. J Biomech 2020; 99:109478. [DOI: 10.1016/j.jbiomech.2019.109478] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 10/28/2019] [Accepted: 10/30/2019] [Indexed: 12/11/2022]
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Bilgi C, Atalık K. Numerical investigation of the effects of blood rheology and wall elasticity in abdominal aortic aneurysm under pulsatile flow conditions. Biorheology 2019; 56:51-71. [PMID: 31045509 DOI: 10.3233/bir-180202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Previous studies on aneurysm modeling have focused on the blood rheology and vessel elasticity separately. The combined effects of blood shear thinning properties and wall elasticity need to be revealed. OBJECTIVE To provide insights on how pulsatile hemodynamics vary with blood rheology and vessel elasticity for a developed abdominal aortic aneurysm (AAA). METHOD An Arbitrary Lagrangian-Eulerian fluid-solid interaction method is adopted with the Newtonian and the shear thinning Carreau constitutive models for the fluid with the linearly elastic and the hyperelastic Yeoh models for the vessel. Finite element based numerical solver is used to simulate the blood flow in the AAA. RESULTS Newtonian model overestimates the velocity values compared to the Carreau model and the difference in the velocity field increases as the shear rate decreases at the instances of the cardiac cycle. The rigid walled simulations display higher deviations in the velocity and wall shear stress with the fluid rheology. The risk indicators show that Newtonian assumption combined with the linearly elastic model may overlook degeneration risk of arterial tissue. CONCLUSIONS Newtonian assumption for the blood as well as modelling the arterial wall as linearly elastic lead to significant differences in oscillatory hemodynamic properties with respect to the use of Carreau fluid together with hyperelastic vessel model, even in large vessel aneurysms.
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Affiliation(s)
- Coşkun Bilgi
- Mechanical Engineering Department, Boğaziçi University, Bebek, Istanbul, Turkey
| | - Kunt Atalık
- Mechanical Engineering Department, Boğaziçi University, Bebek, Istanbul, Turkey
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Polanczyk A, Podgorski M, Polanczyk M, Veshkina N, Zbicinski I, Stefanczyk L, Neumayer C. A novel method for describing biomechanical properties of the aortic wall based on the three-dimensional fluid-structure interaction model. Interact Cardiovasc Thorac Surg 2019; 28:306-315. [PMID: 30101344 DOI: 10.1093/icvts/ivy252] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 06/27/2018] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVES Our goal was to present a novel non-invasive approach for assessment of aortic wall displacement to describe its biomechanical properties during the cardiac cycle. METHODS The fluid-structure interaction (FSI) technique was used to reconstruct aortic wall displacement based on computed tomography angiography and 2-dimensional speckle-tracking technique (2DSTT) data collected from 20 patients [10 with healthy aortas (AA) and 10 with abdominal aortic aneurysms (AAAs)]. The mechanical properties of the wall of the aorta were described by the Yeoh hyperelastic materials model with α and β parameters, and wall displacement was determined with 2DSTT. The mechanical parameters of the wall of the aorta in the FSI model were automatically updated in the calculation loop until the calculated and clinically measured wall movements were the same. RESULTS Results showed 98% accuracy of FSI compared to 2DSTT for AA and AAA (P > 0.05). The mean wall deformation for AA was 2.45 ± 0.12 mm and 2.49 ± 0.10 mm for FSI and 2DSTT, respectively (P = 0.40), whereas that for AAA was 2.84 ± 0.44 mm and 2.88 ± 0.45 mm, respectively (P = 0.83). The FSI analysis indicated that the α and β parameters for AA were equal to 14.35 ± 1.30 N⋅cm-2 and 9.33 ± 1.08 N⋅cm-2, respectively; and for AAA, α was 11.00 ± 0.49 N⋅cm-2 and β was 79.46 ± 4.32 N⋅cm-2. CONCLUSIONS The FSI technique may be successfully applied to assess the mechanical parameters of patient-specific aortic walls using computed tomography angiographic and 2DSTT measurements.
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Affiliation(s)
- Andrzej Polanczyk
- Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Michal Podgorski
- Department of Radiology and Diagnostic Imaging, Medical University of Lodz, Lodz, Poland
| | - Maciej Polanczyk
- Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Natasha Veshkina
- Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Ireneusz Zbicinski
- Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Ludomir Stefanczyk
- Department of Radiology and Diagnostic Imaging, Medical University of Lodz, Lodz, Poland
| | - Christoph Neumayer
- Division of Vascular Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria
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Salman HE, Ramazanli B, Yavuz MM, Yalcin HC. Biomechanical Investigation of Disturbed Hemodynamics-Induced Tissue Degeneration in Abdominal Aortic Aneurysms Using Computational and Experimental Techniques. Front Bioeng Biotechnol 2019; 7:111. [PMID: 31214581 PMCID: PMC6555197 DOI: 10.3389/fbioe.2019.00111] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 05/02/2019] [Indexed: 11/13/2022] Open
Abstract
Abdominal aortic aneurysm (AAA) is the dilatation of the aorta beyond 50% of the normal vessel diameter. It is reported that 4-8% of men and 0.5-1% of women above 50 years of age bear an AAA and it accounts for ~15,000 deaths per year in the United States alone. If left untreated, AAA might gradually expand until rupture; the most catastrophic complication of the aneurysmal disease that is accompanied by a striking overall mortality of 80%. The precise mechanisms leading to AAA rupture remains unclear. Therefore, characterization of disturbed hemodynamics within AAAs will help to understand the mechanobiological development of the condition which will contribute to novel therapies for the condition. Due to geometrical complexities, it is challenging to directly quantify disturbed flows for AAAs clinically. Two other approaches for this investigation are computational modeling and experimental flow measurement. In computational modeling, the problem is first defined mathematically, and the solution is approximated with numerical techniques to get characteristics of flow. In experimental flow measurement, once the setup providing physiological flow pattern in a phantom geometry is constructed, velocity measurement system such as particle image velocimetry (PIV) enables characterization of the flow. We witness increasing number of applications of these complimentary approaches for AAA investigations in recent years. In this paper, we outline the details of computational modeling procedures and experimental settings and summarize important findings from recent studies, which will help researchers for AAA investigations and rupture mechanics.
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Affiliation(s)
| | - Burcu Ramazanli
- Department of Mechanical Engineering, Middle East Technical University, Ankara, Turkey
| | - Mehmet Metin Yavuz
- Department of Mechanical Engineering, Middle East Technical University, Ankara, Turkey
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Computational study on hemodynamic changes in patient-specific proximal neck angulation of abdominal aortic aneurysm with time-varying velocity. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:181-190. [PMID: 30762222 DOI: 10.1007/s13246-019-00728-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 01/21/2019] [Indexed: 12/27/2022]
Abstract
Aneurysms are considered as a critical cardiovascular disease worldwide when they rupture. The clinical understanding of geometrical impact on the flow behaviour and biomechanics of abdominal aortic aneurysm (AAA) is progressively developing. Proximal neck angulations of AAAs are believed to influence the hemodynamic changes and wall shear stress (WSS) within AAAs. Our aim was to perform pulsatile simulations using computational fluid dynamics (CFD) for patient-specific geometry to investigate the influence of severe angular (≥ 60°) neck on AAA's hemodynamic and wall shear stress. The patient's geometrical characteristics were obtained from a computed tomography images database of AAA patients. The AAA geometry was reconstructed using Mimics software. In computational method, blood was assumed Newtonian fluid and an inlet varying velocity waveform in a cardiac cycle was assigned. The CFD study was performed with ANSYS software. The results of flow behaviours indicated that the blood flow through severe bending of angular neck leads to high turbulence and asymmetry of flows within the aneurysm sac resulting in blood recirculation. The high wall shear stress (WSS) occurred near the AAA neck and on surface of aneurysm sac. This study explained and showed flow behaviours and WSS progression within high angular neck AAA and risk prediction of abdominal aorta rupture. We expect that the visualization of blood flow and hemodynamic changes resulted from CFD simulation could be as an extra tool to assist clinicians during a decision making when estimation the risks of interventional procedures.
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Fluid-structure interaction (FSI) analysis of stent-graft for aortic endovascular aneurysm repair (EVAR): Material and structural considerations. J Mech Behav Biomed Mater 2018; 87:95-110. [DOI: 10.1016/j.jmbbm.2018.07.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 01/07/2023]
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