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Wang YYJ, Chen J, Luo DY, Chen H, Deng ZH, Chen MZ, Mi SY, Xie QQ, Zou QQ, Xiong GZ, Bi GS. Effect of differences in proximal neck angles on biomechanics of abdominal aortic aneurysm based on fluid dynamics. Vascular 2024:17085381241273262. [PMID: 39132754 DOI: 10.1177/17085381241273262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
BACKGROUND This study aimed to analyze the effect of proximal neck angulation on the biomechanical indices of abdominal aortic aneurysms (AAA) and to investigate its impact on the risk of AAA rupture. METHODS CT angiography (CTA) data of patients with AAA from January 2015 to January 2022 were collected. Patients were divided into three groups based on the angle of the proximal neck: Group A (∠β ≤ 30°), Group B (30°<∠β ≤ 60°), and Group C (∠β > 60°). Biomechanical indices related to the rupture risk of AAA were analyzed using computational fluid dynamics modeling (CFD-Post) based on the collected data. RESULTS Group A showed slight turbulence in the AAA lumen with a mixed laminar flow pattern. Group B had a regular low-speed eddy line characterized by cross-flow dominated by lumen blood flow and turbulence. In Group C, a few turbulent lines appeared at the proximal neck, accompanied by eddy currents in the lumen expansion area following the AAA shape. Significant differences were found in peak wall stress, shear stress, and the maximum blood flow velocity impact among the three groups. The maximum blood flow velocity at the angle of the proximal neck impact indicated the influence of the proximal neck angle on the blood flow state in the lumen. CONCLUSION As the angle of the proximal neck increased, it caused stronger eddy currents and turbulent blood flow due to a high-speed area near the neck. The region with the largest diameter in the abdominal aortic aneurysm was prone to the highest stress, indicating a higher risk of rupture. The corner of the proximal neck experienced the greatest shear stress, potentially leading to endothelial injury and further enlargement of the aneurysm.
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Affiliation(s)
- Yang-Yi-Jing Wang
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Jie Chen
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Dong-Yang Luo
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Hui Chen
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Zhi-He Deng
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Meng-Zhi Chen
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Si-Yuan Mi
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Qian-Qian Xie
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Qing-Qing Zou
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Guo-Zuo Xiong
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
| | - Guo-Shan Bi
- Department of Vascular Surgery, The Second Affiliated Hospital of University of South China, Hengyang, China
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Valente R, Mourato A, Xavier J, Sousa P, Domingues T, Tavares P, Avril S, Tomás A, Fragata J. Experimental Protocols to Test Aortic Soft Tissues: A Systematic Review. Bioengineering (Basel) 2024; 11:745. [PMID: 39199703 PMCID: PMC11351783 DOI: 10.3390/bioengineering11080745] [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: 06/24/2024] [Accepted: 07/18/2024] [Indexed: 09/01/2024] Open
Abstract
Experimental protocols are fundamental for quantifying the mechanical behaviour of soft tissue. These data are crucial for advancing the understanding of soft tissue mechanics, developing and calibrating constitutive models, and informing the development of more accurate and predictive computational simulations and artificial intelligence tools. This paper offers a comprehensive review of experimental tests conducted on soft aortic tissues, employing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, based on the Scopus, Web of Science, IEEE, Google Scholar and PubMed databases. This study includes a detailed overview of the test method protocols, providing insights into practical methodologies, specimen preparation and full-field measurements. The review also briefly discusses the post-processing methods applied to extract material parameters from experimental data. In particular, the results are analysed and discussed providing representative domains of stress-strain curves for both uniaxial and biaxial tests on human aortic tissue.
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Affiliation(s)
- Rodrigo Valente
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (R.V.); (A.M.)
| | - André Mourato
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (R.V.); (A.M.)
| | - José Xavier
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal; (R.V.); (A.M.)
- Intelligent Systems Associate Laboratory, LASI, 4800-058 Guimarães, Portugal
| | - Pedro Sousa
- INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (P.S.); (P.T.)
| | - Tiago Domingues
- INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (P.S.); (P.T.)
| | - Paulo Tavares
- INEGI, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (P.S.); (P.T.)
| | - Stéphane Avril
- Mines Saint-Etienne, University of Lyon, Inserm, Sainbiose U1059, Campus Santé Innovation, 10, rue de la Marandière, 42270 Saint-Priest-en-Jarez, France;
| | - António Tomás
- Department of Cardiothoracic Surgery, Santa Marta Hospital, Rua de Santa Marta, 1169-024 Lisboa, Portugal; (A.T.); (J.F.)
| | - José Fragata
- Department of Cardiothoracic Surgery, Santa Marta Hospital, Rua de Santa Marta, 1169-024 Lisboa, Portugal; (A.T.); (J.F.)
- Department of Surgery and Human Morphology, NOVA Medical School, Universidade NOVA de Lisboa, Campo Mártires da Pátria, 1169-056 Lisboa, Portugal
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Mansouri M, Therasse E, Montagnon E, Zhan YO, Lessard S, Roy A, Boucher LM, Steinmetz O, Aslan E, Tang A, Chartrand-Lefebvre C, Soulez G. CT analysis of aortic calcifications to predict abdominal aortic aneurysm rupture. Eur Radiol 2024; 34:3903-3911. [PMID: 37999728 DOI: 10.1007/s00330-023-10429-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 09/12/2023] [Accepted: 09/28/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND Abdominal aortic aneurysm (AAA) rupture prediction based on sex and diameter could be improved. The goal was to assess whether aortic calcification distribution could better predict AAA rupture through machine learning and LASSO regression. METHODOLOGY In this retrospective study, 80 patients treated for a ruptured AAA between January 2001 and August 2018 were matched with 80 non-ruptured patients based on maximal AAA diameter, age, and sex. Calcification volume and dispersion, morphologic, and clinical variables were compared between both groups using a univariable analysis with p = 0.05 and multivariable analysis through machine learning and LASSO regression. We used AUC for machine learning and odds ratios for regression to measure performance. RESULTS Mean age of patients was 74.0 ± 8.4 years and 89% were men. AAA diameters were equivalent in both groups (80.9 ± 17.5 vs 79.0 ± 17.3 mm, p = 0.505). Ruptured aneurysms contained a smaller number of calcification aggregates (18.0 ± 17.9 vs 25.6 ± 18.9, p = 0.010) and were less likely to have a proximal neck (45.0% vs 76.3%, p < 0.001). In the machine learning analysis, 5 variables were associated to AAA rupture: proximal neck, antiplatelet use, calcification number, Euclidian distance between calcifications, and standard deviation of the Euclidian distance. A follow-up LASSO regression was concomitant with the findings of the machine learning analysis regarding calcification dispersion but discordant on calcification number. CONCLUSION There might be more to AAA calcifications that what is known in the present literature. We need larger prospective studies to investigate if indeed, calcification dispersion affects rupture risk. CLINICAL RELEVANCE STATEMENT Ruptured aneurysms are possibly more likely to have their calcification volume concentrated in a smaller geographical area. KEY POINTS • Abdominal aortic aneurysm (AAA) rupture prediction based on sex and diameter could be improved. • For a given calcification volume, AAAs with well-distributed calcification clusters could be less likely to rupture. • A machine learning model including AAA calcifications better predicts rupture compared to a model based solely on maximal diameter and sex alone, although it might be prone to overfitting.
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Affiliation(s)
- Mohamed Mansouri
- Department of Radiology, McGill University Health Center (MUHC), Montréal, Québec, Canada
- Department of Diagnostic Radiology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Eric Therasse
- Department of Radiology, Centre Hospitalier de L'Université de Montréal (CHUM), 1051 Rue Sanguinet, Montreal, QC, H2X 3E4, Canada
- Department of Radiology, Radiation Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
- Laboratory of Clinical Imaging Processing, Centre Hospitalier de L'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada
| | - Emmanuel Montagnon
- Laboratory of Clinical Imaging Processing, Centre Hospitalier de L'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada
| | - Ying Olivier Zhan
- Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Simon Lessard
- Laboratory of Clinical Imaging Processing, Centre Hospitalier de L'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada
| | - Aubert Roy
- Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Louis-Martin Boucher
- Department of Radiology, McGill University Health Center (MUHC), Montréal, Québec, Canada
- Department of Diagnostic Radiology, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Oren Steinmetz
- Department of Vascular Surgery, McGill University Health Center (MUHC), Montréal, Québec, Canada
- Department of Vascular Surgery, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Emre Aslan
- Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - An Tang
- Department of Radiology, Centre Hospitalier de L'Université de Montréal (CHUM), 1051 Rue Sanguinet, Montreal, QC, H2X 3E4, Canada
- Department of Radiology, Radiation Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
- Laboratory of Clinical Imaging Processing, Centre Hospitalier de L'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada
| | - Carl Chartrand-Lefebvre
- Department of Radiology, Centre Hospitalier de L'Université de Montréal (CHUM), 1051 Rue Sanguinet, Montreal, QC, H2X 3E4, Canada
- Department of Radiology, Radiation Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
- Laboratory of Clinical Imaging Processing, Centre Hospitalier de L'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada
| | - Gilles Soulez
- Department of Radiology, Centre Hospitalier de L'Université de Montréal (CHUM), 1051 Rue Sanguinet, Montreal, QC, H2X 3E4, Canada.
- Department of Radiology, Radiation Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.
- Laboratory of Clinical Imaging Processing, Centre Hospitalier de L'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada.
- Institute of Biomedical Engineering, Université de Montréal, Montréal, Québec, Canada.
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Debus S, Mansilha A, Halliday A. Hans-Henning Eckstein (1955 - 2024). Eur J Vasc Endovasc Surg 2024:S1078-5884(24)00264-8. [PMID: 38518859 DOI: 10.1016/j.ejvs.2024.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
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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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Derycke L, Avril S, Millon A. Patient-Specific Numerical Simulations of Endovascular Procedures in Complex Aortic Pathologies: Review and Clinical Perspectives. J Clin Med 2023; 12:jcm12030766. [PMID: 36769418 PMCID: PMC9917982 DOI: 10.3390/jcm12030766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
The endovascular technique is used in the first line treatment in many complex aortic pathologies. Its clinical outcome is mostly determined by the appropriate selection of a stent-graft for a specific patient and the operator's experience. New tools are still needed to assist practitioners with decision making before and during procedures. For this purpose, numerical simulation enables the digital reproduction of an endovascular intervention with various degrees of accuracy. In this review, we introduce the basic principles and discuss the current literature regarding the use of numerical simulation for endovascular management of complex aortic diseases. Further, we give the future direction of everyday clinical applications, showing that numerical simulation is about to revolutionize how we plan and carry out endovascular interventions.
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Affiliation(s)
- Lucie Derycke
- Department of Cardio-Vascular and Vascular Surgery, Hôpital Européen Georges Pompidou, F-75015 Paris, France
- Centre CIS, Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France
| | - Stephane Avril
- Centre CIS, Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France
| | - Antoine Millon
- Department of Vascular and Endovascular Surgery, Hospices Civils de Lyon, Louis Pradel University Hospital, F-69500 Bron, France
- Correspondence:
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Liu H, Chen Z, Tang C, Fan H, Mai X, Cai J, Qiao T. High-density thrombus and maximum transverse diameter on multi-spiral computed tomography angiography combine to predict abdominal aortic aneurysm rupture. Front Cardiovasc Med 2022; 9:951264. [PMID: 36247433 PMCID: PMC9561396 DOI: 10.3389/fcvm.2022.951264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/29/2022] [Indexed: 12/03/2022] Open
Abstract
Objective We attempted to measure maximum transverse diameter (MTD) of and CT values of ILT by using multi-spiral computed tomography angiography (MSCTA) to investigate the predictive value of MTD with different CT values of thrombus on the risk of AAA rupture. Methods Forty-five intact abdominal aortic aneurysms (IAAA) and 17 ruptured abdominal aortic aneurysms (RAAA) were included in this study. MTD and CT values in their planes were measured from MSCTA images and aneurysm lumen and thrombus volumes were calculated for the range of different CT values. Results The median of maximum CT value of thrombus at the plane of MTD was higher in RAAA (107.0 HU) than the median in IAAA (84.5 HU) (P < 0.001). Univariate logistic regression analysis showed that the maximum CT value was a risk factor for RAAA (P < 0.001). It was further found that the area under the ROC curve for thrombus maximum CT value in the MTD plane to predict RAAA was 0.848 (P < 0.001), with a cut-off value of 97.5 HU, a sensitivity of 82.35%, and a specificity of 84.44%. And the MTD of the abnormal lumen combined with the maximum CT value at its plane predicted RAAA with an area under the ROC curve of 0.901, a sensitivity of 76.47%, and a specificity of 97.78%. The further analysis of thrombus volume in the range of different CT value showed that median thrombus volume in RAAA in the range of 30 HU~150 HU was 124.2 cm3 which was higher than the median of 81.4 cm3 in IAAA (P = 0.005). To exclude confounding factors (aneurysm volume), we calculated the standardized thrombus (ILT volume/total aneurysm volume), and the thrombus volume in the range of 30 HU~150 HU in RAAA was positively correlated with the standardized thrombus volume (ρ = 0.885, P < 0.001), while the thrombus volume in the range of −100 HU~30 HU was not correlated with it (ρ = 0.309, P = 0.228). Conclusions High-density ILT shown on MSCTA in AAAs is associated with aneurysm rupture, and its maximum transverse diameter combined with the maximum CT value in its plane is a better predictor of RAAA.
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Affiliation(s)
- Heqian Liu
- Department of Vascular Surgery, Nanjing Drum Tower Hospital Clinical College of Xuzhou Medical University, Nanjing, China
| | - Zhipeng Chen
- Department of Vascular Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Chen Tang
- Department of Vascular Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Haijian Fan
- Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Xiaoli Mai
- Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Jing Cai
- Department of Vascular Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
- *Correspondence: Jing Cai
| | - Tong Qiao
- Department of Vascular Surgery, Nanjing Drum Tower Hospital Clinical College of Xuzhou Medical University, Nanjing, China
- Tong Qiao
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Kang S, Nashar S, Masud A. Blood-Artery Interaction in Calcified Aortas and Abdominal Aortic Aneurysms. EXTREME MECHANICS LETTERS 2022; 54:101684. [PMID: 35874896 PMCID: PMC9302709 DOI: 10.1016/j.eml.2022.101684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A stabilized FSI method is presented for coupling shear-rate dependent model of blood with finitely deforming anisotropic hyperelastic model of arteries. The blood-artery coupling conditions are weakly enforced to accommodate non-matching blood-artery meshes which provides great flexibility in independent discretization of fluid and solid subdomains in the patient-specific geometric models. The variationally derived interface coupling terms play an important role in the concurrent solution of the nonlinear mixed-field problem across non-matching discretizations. Two test cases are presented that investigate the effect of growth of aortic aneurysm on local changes in blood flow and stress concentrations in calcified arteries under pulsating flows to highlight the clinical relevance of the proposed method for cardiovascular applications.
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Affiliation(s)
- Soonpil Kang
- Graduate research assistant, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Sharbel Nashar
- Graduate research assistant, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Arif Masud
- John and Eileen Blumenschein Professor. Department of Civil and Environmental Engineering - Grainger College of Engineering, and Department of Translational and Biomedical Sciences - Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
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McLennan S, Soulez G, Mongrain R, Mohammadi H, Pfister M, Lessard S, Jabbour G, Therasse E. Impact of calcification modeling to improve image fusion accuracy for endovascular aortic aneurysm repair. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3556. [PMID: 34854247 DOI: 10.1002/cnm.3556] [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: 09/25/2021] [Revised: 11/18/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
Since the 1990s, endovascular aortic aneurysm repair (EVAR) has become a common alternative to open surgery for the treatment of abdominal aortic aneurysms (AAAs). To aid the deployment of stent-grafts, fluoroscopic image guidance can be enhanced using preoperative simulation and intraoperative image fusion techniques. However, the impact of calcification (Ca) presence on the guidance accuracy of such techniques is yet to be considered. In the present work, we introduce a guidance tool that accounts for patient-specific Ca presence. Numerical simulations of EVAR were developed for 12 elective AAA patients, both with (With-Ca) and without (No-Ca) Ca consideration. To assess the accuracy of the simulations, the image results were overlaid on corresponding intraoperative images and the overlay error was measured at selected anatomical landmarks. With this approach we gained insight into the impact of Ca presence on image fusion accuracy. Inclusion of Ca improved mean image fusion accuracy by 8.68 ± 4.59%. In addition, a positive correlation between the relative Ca presence and the image fusion accuracy was found (R = .753, p < .005). Our results suggest that considering Ca presence in patient-specific EVAR simulations increases the reliability of EVAR image guidance techniques that utilize numerical simulation, especially for patients with severe aortic Ca presence.
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Affiliation(s)
- Stewart McLennan
- Mechanical Engineering Department, McGill University, Montréal, Quebec, Canada
| | - Gilles Soulez
- Department of Radiology Radiation-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Rosaire Mongrain
- Mechanical Engineering Department, McGill University, Montréal, Quebec, Canada
| | - Hossein Mohammadi
- Mechanical Engineering Department, McGill University, Montréal, Quebec, Canada
| | | | - Simon Lessard
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Quebec, Canada
| | - Gilbert Jabbour
- Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Eric Therasse
- Department of Radiology Radiation-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Quebec, Canada
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Avril S, Gee MW, Hemmler A, Rugonyi S. Patient-specific computational modeling of endovascular aneurysm repair: State of the art and future directions. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3529. [PMID: 34490740 DOI: 10.1002/cnm.3529] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Endovascular aortic repair (EVAR) has become the preferred intervention option for aortic aneurysms and dissections. This is because EVAR is much less invasive than the alternative open surgery repair. While in-hospital mortality rates are smaller for EVAR than open repair (1%-2% vs. 3%-5%), the early benefits of EVAR are lost after 3 years due to larger rates of complications in the EVAR group. Clinicians follow instructions for use (IFU) when possible, but are left with personal experience on how to best proceed and what choices to make with respect to stent-graft (SG) model choice, sizing, procedural options, and their implications on long-term outcomes. Computational modeling of SG deployment in EVAR and tissue remodeling after intervention offers an alternative way of testing SG designs in silico, in a personalized way before intervention, to ultimately select the strategies leading to better outcomes. Further, computational modeling can be used in the optimal design of SGs in cases of complex geometries. In this review, we address some of the difficulties and successes associated with computational modeling of EVAR procedures. There is still work to be done in all areas of EVAR in silico modeling, including model validation, before models can be applied in the clinic, but much progress has already been made. Critical to clinical implementation are current efforts focusing on developing fast algorithms that can achieve (near) real-time solutions, as well as ways of dealing with inherent uncertainties related to patient aortic wall degradation on an individualized basis. We are optimistic that EVAR modeling in the clinic will soon become a reality to help clinicians optimize EVAR interventions and ultimately reduce EVAR-associated complications.
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Affiliation(s)
- Stéphane Avril
- Mines Saint-Étienne, Univ Lyon, Univ Jean Monnet, INSERM, Saint-Étienne, France
| | - Michael W Gee
- Mechanics & High Performance Computing Group, Department of Mechanical Engineering, Technical University of Munich, Garching, Germany
| | - André Hemmler
- Mechanics & High Performance Computing Group, Department of Mechanical Engineering, Technical University of Munich, Garching, Germany
| | - Sandra Rugonyi
- Biomedical Engineering Department, Oregon Health & Science University, Portland, Oregon, USA
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DIAS-NETO M, NEVES E, SOUSA-NUNES F, HENRIQUES-COELHO T, SAMPAIO S. Abdominal aortic aneurysm calcification: trying to identify a reliable semiquantitative method. THE JOURNAL OF CARDIOVASCULAR SURGERY 2021; 62:51-58. [DOI: 10.23736/s0021-9509.18.10132-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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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13
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Doyle BJ, Bappoo N, Syed MB, Forsythe RO, Powell JT, Conlisk N, Hoskins PR, McBride OM, Shah AS, Norman PE, Newby DE. Biomechanical Assessment Predicts Aneurysm Related Events in Patients with Abdominal Aortic Aneurysm. Eur J Vasc Endovasc Surg 2020; 60:365-373. [DOI: 10.1016/j.ejvs.2020.02.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/04/2020] [Accepted: 02/26/2020] [Indexed: 01/09/2023]
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14
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Predictors of Abdominal Aortic Aneurysm Risks. Bioengineering (Basel) 2020; 7:bioengineering7030079. [PMID: 32707846 PMCID: PMC7552640 DOI: 10.3390/bioengineering7030079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 11/16/2022] Open
Abstract
Computational biomechanics via finite element analysis (FEA) has long promised a means of assessing patient-specific abdominal aortic aneurysm (AAA) rupture risk with greater efficacy than current clinically used size-based criteria. The pursuit stems from the notion that AAA rupture occurs when wall stress exceeds wall strength. Quantification of peak (maximum) wall stress (PWS) has been at the cornerstone of this research, with numerous studies having demonstrated that PWS better differentiates ruptured AAAs from non-ruptured AAAs. In contrast to wall stress models, which have become progressively more sophisticated, there has been relatively little progress in estimating patient-specific wall strength. This is because wall strength cannot be inferred non-invasively, and measurements from excised patient tissues show a large spectrum of wall strength values. In this review, we highlight studies that investigated the relationship between biomechanics and AAA rupture risk. We conclude that combining wall stress and wall strength approximations should provide better estimations of AAA rupture risk. However, before personalized biomechanical AAA risk assessment can become a reality, better methods for estimating patient-specific wall properties or surrogate markers of aortic wall degradation are needed. Artificial intelligence methods can be key in stratifying patients, leading to personalized AAA risk assessment.
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15
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Wu D, Wang S, Xie J, Mao B, Li B, Jin C, Feng Y, Li G, Liu Y. Hemodynamic Mechanism of Coronary Artery Aneurysm High Occurrence on Right Coronary Artery. Front Physiol 2020; 11:323. [PMID: 32425805 PMCID: PMC7212456 DOI: 10.3389/fphys.2020.00323] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 03/20/2020] [Indexed: 11/17/2022] Open
Abstract
The abnormal diameter of the coronary artery is twice or more than the normal diameter, which is a coronary artery aneurysm (CAA). According to the clinical statistics, CAA shows high occurrence on right coronary artery (RCA). The most common cause of CAA in adults is atherosclerosis, which destroys the elastic fibers in the middle layer of the blood vessel. Under the intravascular pressure, the weak wall bulges outward and form CAA. This article aims to explain the hemodynamic mechanism of coronary artery aneurysm shows high occurrence on RCA. Occurrence of CAA was simulated by the volume growth of coronary artery. Firstly, a 0–3D multi-scale model of normal coronary artery was constructed to obtain the hemodynamic environments of coronary artery. Then, fluid-structure interaction of normal and atherosclerotic blood vessel was performed to obtain volume growth rate of the coronary artery. Atherosclerosis was simulated by modifying Young’s modulus in middle layer of the blood vessel. Finally, creep simulation was performed to compare the deformation of the blood vessels under the accumulation of time. Under normal condition, the volume growth rate of the RCA is 2.28 times and 1.55 times of the LAD and the LCX. After atherosclerosis, the volume growth rate of the RCA was 2.69 times and 2.12 times of the LAD and the LCX. And the volume growth rate of the RCA was 3.85 times and 3.45 times of the LAD and the LCX after further deepening of atherosclerosis. The expansion time above the average volume growth rate of the RCA, the LAD and the LCX respectively were 0.194, 0.168 and 0.179 s. The RCA is 2.06 times the original, the LAD and LCX are 1.53 times and 1.56 times after 10 years in creep simulation. It can be concluded that the RCA is more prone to aneurysms originated from the larger expansion of the RCA under normal physiological condition, and the larger expansion is magnified under atherosclerosis condition with destroyed vessel elasticity, and further magnified during the time accumulated viscoelastic creep to develop to aneurysm eventually.
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Affiliation(s)
- Dandan Wu
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Sirui Wang
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Jinsheng Xie
- Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Boyan Mao
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Bao Li
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Chunbo Jin
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Yue Feng
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Gaoyang Li
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Youjun Liu
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
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16
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Hemmler A, Lin A, Thierfelder N, Franz T, Gee MW, Bezuidenhout D. Customized stent-grafts for endovascular aneurysm repair with challenging necks: A numerical proof of concept. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3316. [PMID: 32022404 DOI: 10.1002/cnm.3316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/05/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Endovascular aortic repair (EVAR) is a challenging intervention whose long-term success strongly depends on the appropriate stent-graft (SG) selection and sizing. Most off-the-shelf SGs are straight and cylindrical. Especially in challenging vessel morphologies, the morphology of off-the-shelf SGs is not able to meet the patient-specific demands. Advanced manufacturing technologies facilitate the development of highly customized SGs. Customized SGs that have the same morphology as the luminal vessel surface could considerably improve the quality of the EVAR outcome with reduced likelihoods of EVAR related complications such as endoleaks type I and SG migration. In this contribution, we use an in silico EVAR methodology that approximates the deployed state of the elastically deformable SG in a hyperelastic, anisotropic vessel. The in silico EVAR results of off-the-shelf SGs and customized SGs are compared qualitatively and quantitatively in terms of mechanical and geometrical parameters such as stent stresses, contact tractions, SG fixation forces and the SG-vessel attachment. In a numerical proof of concept, eight different vessel morphologies, such as a conical vessel, a barrel shaped vessel and a curved vessel, are used to demonstrate the added value of customized SGs compared to off-the-shelf SGs. The numerical investigation has shown large benefits of the highly customized SGs compared to off-the-shelf SGs with respect to a better SG-vessel attachment and a considerable increase in SG fixation forces of up to 50% which indicate decreased likelihoods of EVAR related complications. Hence, this numerical proof of concept motivates further research and development of highly customized SGs for the use in challenging vessel morphologies.
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Affiliation(s)
- André Hemmler
- Mechanics & High Performance Computing Group, Technische Universität München, Garching bei München, Germany
| | - Andrew Lin
- Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| | - Nikolaus Thierfelder
- Herzchirurgische Klinik und Poliklinik, Ludwig-Maximilians-Universität München, München, Germany
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Observatory, South Africa
| | - Michael W Gee
- Mechanics & High Performance Computing Group, Technische Universität München, Garching bei München, Germany
| | - Deon Bezuidenhout
- Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
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17
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Kyriakou F, Dempster W, Nash D. Analysing The Cross-Section of The Abdominal Aortic Aneurysm Neck and Its Effects on Stent Deployment. Sci Rep 2020; 10:4673. [PMID: 32170088 PMCID: PMC7070033 DOI: 10.1038/s41598-020-61578-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/28/2020] [Indexed: 11/08/2022] Open
Abstract
Stent graft devices for the treatment of abdominal aortic aneurysms (AAAs) are being increasingly used worldwide. Yet, during modelling and optimization of these devices, as well as in clinical practice, vascular sections are idealized, possibly compromising the effectiveness of the intervention. In this study, we challenge the commonly used approximation of the circular cross-section of the aorta and identify the implications of this approximation to the mechanical assessment of stent grafts. Using computed tomography angiography (CTA) data from 258 AAA patients, the lumen of the aneurysmal neck was analysed. The cross-section of the aortic neck was found to be an independent variable, uncorrelated to other geometrical aspects of the region, and its shape was non-circular reaching elliptical ratios as low as 0.77. These results were used to design a finite element analysis (FEA) study for the assessment of a ring stent bundle deployed under a variety of aortic cross-sections. Results showed that the most common clinical approximations of the vascular cross-section can be a source of significant error when calculating the maximum stent strains (underestimated by up to 69%) and radial forces (overestimated by up to 13%). Nevertheless, a less frequently used average approximation was shown to yield satisfactory results (5% and 2% of divergence respectively).
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Affiliation(s)
- Faidon Kyriakou
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, UK.
| | - William Dempster
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, UK
| | - David Nash
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, UK
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18
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Hemmler A, Lutz B, Reeps C, Gee MW. In silico study of vessel and stent-graft parameters on the potential success of endovascular aneurysm repair. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3237. [PMID: 31315160 DOI: 10.1002/cnm.3237] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/29/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
The variety of stent-graft (SG) design variables (eg, SG type and degree of SG oversizing) and the complexity of decision making whether a patient is suitable for endovascular aneurysm repair (EVAR) raise the need for the development of predictive tools to assist clinicians in the preinterventional planning phase. Recently, some in silico EVAR methods have been developed to predict the deployed SG configuration. However, only few studies investigated how to assess the in silico EVAR outcome with respect to EVAR complication likelihoods (eg, endoleaks and SG migration). Based on a large literature study, in this contribution, 20 mechanical and geometrical parameters (eg, SG drag force and SG fixation force) are defined to evaluate the quality of the in silico EVAR outcome. For a cohort of n = 146 realizations of parameterized vessel and SG geometries, the in silico EVAR results are studied with respect to these mechanical and geometrical parameters. All degrees of SG oversizing in the range between 5% and 40% are investigated continuously by a computationally efficient parameter continuation approach. The in silico investigations have shown that the mechanical and geometrical parameters are able to indicate candidates at high risk of postinterventional complications. Hence, this study provides the basis for the development of a simulation-based metric to assess the potential success of EVAR based on engineering parameters.
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Affiliation(s)
- André Hemmler
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, Garching b. München, 85748, Germany
| | - Brigitta Lutz
- Klinik für Viszeral-, Thorax- und Gefäßchirurgie, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, Dresden, 01307, Germany
| | - Christian Reeps
- Klinik für Viszeral-, Thorax- und Gefäßchirurgie, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, Dresden, 01307, Germany
| | - Michael W Gee
- Mechanics & High Performance Computing Group, Technische Universität München, Parkring 35, Garching b. München, 85748, Germany
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19
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Doyle MG, Crawford SA, Osman E, Hatch J, Tse LW, Amon CH, Forbes TL. Comparison of Qualitative and Quantitative Assessments of Iliac Artery Tortuosity and Calcification. Vasc Endovascular Surg 2019; 53:464-469. [DOI: 10.1177/1538574419858163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction: During endovascular aneurysm repair, the iliac artery typically serves as a conduit for device delivery. The degree of tortuosity and calcification in the iliac artery ultimately determines whether the device can successfully traverse the vessel. These 2 parameters can be assessed using qualitative approaches or calculated using quantitative methods based on the Society for Vascular Surgery (SVS) reporting standards. The objective of this study was to determine whether qualitative methods are sufficient to accurately assess iliac artery tortuosity and calcification by calculating interobserver variability and comparing them to the SVS Reporting Standards. Methods: Three vascular surgeons reviewed preoperative computed tomography scans for 50 patients who underwent fenestrated endovascular aneurysm repair and qualitatively assessed left and right iliac artery tortuosity and calcification. Iliac artery geometries were segmented from these image sets. Tortuosity index and calcification length ratio were calculated and categorized based on the SVS Reporting Standards. Results: Interobserver variability was calculated for the qualitative assessments using interclass correlation coefficients. For tortuosity index, among the 3 observers, good agreement was found for the left iliac artery and fair agreement was found for the right. For calcification length ratio, excellent agreement was found for both iliac arteries. When compared to the quantitative assessment, the qualitative assessments underpredicted tortuosity in 2.3% of cases, matched the quantitative values in 16.7% of cases, and overpredicted tortuosity in 81.0% of cases. The qualitative assessments underpredicted calcification in 46.3% of cases, matched the quantitative values in 49.3% of cases, and overpredicted calcification in 4.3% of cases. Conclusion: Qualitative assessment of iliac artery tortuosity showed fair-to-good interobserver agreement and poor agreement to SVS Reporting Standards. Qualitative assessment of iliac artery calcification showed excellent interobserver agreement and fair agreement to SVS Reporting Standards. These trends should be considered when qualitative reporting methodologies are used.
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Affiliation(s)
- Matthew G. Doyle
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, Canada
| | - Sean A. Crawford
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Elrasheed Osman
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, Canada
| | - Jessica Hatch
- Division of Vascular Surgery and Division of General Surgery, Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Leonard W. Tse
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, Canada
| | - Cristina H. Amon
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Thomas L. Forbes
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, Canada
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20
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Patient-specific in silico endovascular repair of abdominal aortic aneurysms: application and validation. Biomech Model Mechanobiol 2019; 18:983-1004. [PMID: 30834463 DOI: 10.1007/s10237-019-01125-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 02/05/2019] [Indexed: 10/27/2022]
Abstract
Non-negligible postinterventional complication rates after endovascular aneurysm repair (EVAR) leave room for further improvements. Since the potential success of EVAR depends on various patient-specific factors, such as the complexity of the vessel geometry and the physiological state of the vessel, in silico models can be a valuable tool in the preinterventional planning phase. A suitable in silico EVAR methodology applied to patient-specific cases can be used to predict stent-graft (SG)-related complications, such as SG migration, endoleaks or tissue remodeling-induced aortic neck dilatation and to improve the selection and sizing process of SGs. In this contribution, we apply an in silico EVAR methodology that predicts the final state of the deployed SG after intervention to three clinical cases. A novel qualitative and quantitative validation methodology, that is based on a comparison between in silico results and postinterventional CT data, is presented. The validation methodology compares average stent diameters pseudo-continuously along the total length of the deployed SG. The validation of the in silico results shows very good agreement proving the potential of using in silico approaches in the preinterventional planning of EVAR. We consider models of bifurcated, marketed SGs as well as sophisticated models of patient-specific vessels that include intraluminal thrombus, calcifications and an anisotropic model for the vessel wall. We exemplarily show the additional benefit and applicability of in silico EVAR approaches to clinical cases by evaluating mechanical quantities with the potential to assess the quality of SG fixation and sealing such as contact tractions between SG and vessel as well as SG-induced tissue overstresses.
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21
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Pelisek J, Hegenloh R, Bauer S, Metschl S, Pauli J, Glukha N, Busch A, Reutersberg B, Kallmayer M, Trenner M, Wendorff H, Tsantilas P, Schmid S, Knappich C, Schaeffer C, Stadlbauer T, Biro G, Wertern U, Meisner F, Stoklasa K, Menges AL, Radu O, Dallmann-Sieber S, Karlas A, Knipfer E, Reeps C, Zimmermann A, Maegdefessel L, Eckstein HH. Biobanking: Objectives, Requirements, and Future Challenges-Experiences from the Munich Vascular Biobank. J Clin Med 2019; 8:jcm8020251. [PMID: 30781475 PMCID: PMC6406278 DOI: 10.3390/jcm8020251] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/01/2019] [Accepted: 02/12/2019] [Indexed: 12/13/2022] Open
Abstract
Collecting biological tissue samples in a biobank grants a unique opportunity to validate diagnostic and therapeutic strategies for translational and clinical research. In the present work, we provide our long-standing experience in establishing and maintaining a biobank of vascular tissue samples, including the evaluation of tissue quality, especially in formalin-fixed paraffin-embedded specimens (FFPE). Our Munich Vascular Biobank includes, thus far, vascular biomaterial from patients with high-grade carotid artery stenosis (n = 1567), peripheral arterial disease (n = 703), and abdominal aortic aneurysm (n = 481) from our Department of Vascular and Endovascular Surgery (January 2004–December 2018). Vascular tissue samples are continuously processed and characterized to assess tissue morphology, histological quality, cellular composition, inflammation, calcification, neovascularization, and the content of elastin and collagen fibers. Atherosclerotic plaques are further classified in accordance with the American Heart Association (AHA), and plaque stability is determined. In order to assess the quality of RNA from FFPE tissue samples over time (2009–2018), RNA integrity number (RIN) and the extent of RNA fragmentation were evaluated. Expression analysis was performed with two housekeeping genes—glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-actin (ACTB)—using TaqMan-based quantitative reverse-transcription polymerase chain reaction (qRT)-PCR. FFPE biospecimens demonstrated unaltered RNA stability over time for up to 10 years. Furthermore, we provide a protocol for processing tissue samples in our Munich Vascular Biobank. In this work, we demonstrate that biobanking is an important tool not only for scientific research but also for clinical usage and personalized medicine.
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Affiliation(s)
- Jaroslav Pelisek
- DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, 80636 Munich, Germany.
| | - Renate Hegenloh
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Sabine Bauer
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Susanne Metschl
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Jessica Pauli
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Nadiya Glukha
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Albert Busch
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Benedikt Reutersberg
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Michael Kallmayer
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Matthias Trenner
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Heiko Wendorff
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Pavlos Tsantilas
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Sofie Schmid
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Christoph Knappich
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Christoph Schaeffer
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Thomas Stadlbauer
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Gabor Biro
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Uta Wertern
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Franz Meisner
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Kerstin Stoklasa
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Anna-Leonie Menges
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Oksana Radu
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Sabine Dallmann-Sieber
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Angelos Karlas
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Eva Knipfer
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Christian Reeps
- University Centre for Vascular Medicine and Department of Vascular Surgery, University Hospital Carl Gustav Carus, Dresden University of Technology, 01307 Dresden, Germany.
| | - Alexander Zimmermann
- Department of Vascular and Endovascular Surgery, Technische Universität München, 81675 Munich, Germany.
| | - Lars Maegdefessel
- DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, 80636 Munich, Germany.
| | - Hans-Henning Eckstein
- DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, 80636 Munich, Germany.
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22
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A modular inverse elastostatics approach to resolve the pressure-induced stress state for in vivo imaging based cardiovascular modeling. J Mech Behav Biomed Mater 2018; 85:124-133. [DOI: 10.1016/j.jmbbm.2018.05.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Accepted: 05/22/2018] [Indexed: 01/18/2023]
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23
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Sanford RM, Crawford SA, Genis H, Doyle MG, Forbes TL, Amon CH. Predicting Rotation in Fenestrated Endovascular Aneurysm Repair Using Finite Element Analysis. J Biomech Eng 2018; 140:2681000. [DOI: 10.1115/1.4040124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Indexed: 01/20/2023]
Abstract
Fenestrated endovascular aneurysm repair (FEVAR) is a minimally invasive method of abdominal aortic aneurysm (AAA) repair utilized in patients with complex vessel anatomies. Stent grafts (SG) used in this process contain fenestrations within the device that need to be aligned with the visceral arteries upon successful SG deployment. Proper alignment is crucial to maintain blood flow to these arteries and avoid surgical complications. During fenestrated SG deployment, rotation of the SG can occur during the unsheathing process. This leads to misalignment of the vessels, and the fenestrations and is associated with poor clinical outcomes. The aim of this study was to develop a computational model of the FEVAR process to predict SG rotation. Six patient-specific cases are presented and compared with surgical case data. Realistic material properties, frictional effects, deployment methods, and boundary conditions are included in the model. A mean simulation error of 2 deg (range 1–4 deg) was observed. This model was then used to conduct a parameter study of frictional properties to see if rotation could be minimized. This study showed that increasing or decreasing the coefficients of friction (COF) between the sheath and the vessel walls would decrease the amount of rotation observed. Our model accurately predicts the amount of SG rotation observed during FEVAR and can be used as a preoperative planning tool within the surgical workflow.
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Affiliation(s)
- Ryan M. Sanford
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada
| | - Sean A. Crawford
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, ON M5G 2C4, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Helen Genis
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, ON M5G 2C4, Canada
| | - Matthew G. Doyle
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, ON M5G 2C4, Canada
| | - Thomas L. Forbes
- Division of Vascular Surgery, Peter Munk Cardiac Centre, University Health Network and University of Toronto, Toronto, ON M5G 2C4, Canada
| | - Cristina H. Amon
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
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Hemmler A, Lutz B, Reeps C, Kalender G, Gee MW. A methodology for in silico endovascular repair of abdominal aortic aneurysms. Biomech Model Mechanobiol 2018; 17:1139-1164. [PMID: 29752606 DOI: 10.1007/s10237-018-1020-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/23/2018] [Indexed: 11/29/2022]
Abstract
Endovascular aneurysm repair (EVAR) can involve some unfavorable complications such as endoleaks or stent-graft (SG) migration. Such complications, resulting from the complex mechanical interaction of vascular tissue, SG and blood flow or incompatibility of SG design and vessel geometry, are difficult to predict. Computational vascular mechanics models can be a predictive tool for the selection, sizing and placement process of SGs depending on the patient-specific vessel geometry and hence reduce the risk of potential complications after EVAR. In this contribution, we present a new in silico EVAR methodology to predict the final state of the deployed SG after intervention and evaluate the mechanical state of vessel and SG, such as contact forces and wall stresses. A novel method to account for residual strains and stresses in SGs, resulting from the precompression of stents during the assembly process of SGs, is presented. We suggest a parameter continuation approach to model various different sizes of SGs within one in silico EVAR simulation which can be a valuable tool when investigating the issue of SG oversizing. The applicability and robustness of the proposed methods are demonstrated on the example of a synthetic abdominal aortic aneurysm geometry.
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Affiliation(s)
- André Hemmler
- Mechanics and High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany
| | - Brigitta Lutz
- Klinik für Viszeral-, Thorax- und Gefäßchirurgie, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - Christian Reeps
- Klinik für Viszeral-, Thorax- und Gefäßchirurgie, Universitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - Günay Kalender
- Klinik für vaskuläre und endovaskuläre Chirurgie, DRK Kliniken Berlin, Salvador-Allende-Straße 2-8, 12559, Berlin, Germany
| | - Michael W Gee
- Mechanics and High Performance Computing Group, Technische Universität München, Parkring 35, 85748, Garching b. München, Germany.
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25
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On the influence of wall calcification and intraluminal thrombus on prediction of abdominal aortic aneurysm rupture. J Vasc Surg 2018; 67:1234-1246.e2. [DOI: 10.1016/j.jvs.2017.05.086] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/02/2017] [Indexed: 01/14/2023]
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26
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The Mechanical Characterisation of Bovine Embolus Analogues Under Various Loading Conditions. Cardiovasc Eng Technol 2018; 9:489-502. [DOI: 10.1007/s13239-018-0352-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
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Doyle MG, Crawford SA, Osman E, Eisenberg N, Tse LW, Amon CH, Forbes TL. Analysis of Iliac Artery Geometric Properties in Fenestrated Aortic Stent Graft Rotation. Vasc Endovascular Surg 2018; 52:188-194. [DOI: 10.1177/1538574418754989] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Introduction: A complication of fenestrated endovascular aneurysm repair is the potential for stent graft rotation during deployment causing fenestration misalignment and branch artery occlusion. The objective of this study is to demonstrate that this rotation is caused by a buildup of rotational energy as the device is delivered through the iliac arteries and to quantify iliac artery geometric properties associated with device rotation. Methods: A retrospective clinical study was undertaken in which iliac artery geometric properties were assessed from preoperative imaging for 42 cases divided into 2 groups: 27 in the nonrotation group and 15 in the rotation group. Preoperative computed tomography scans were segmented, and the iliac artery centerlines were determined. Iliac artery tortuosity, curvature, torsion, and diameter were calculated from the centerline and the segmented vessel geometry. Results: The total iliac artery net torsion was found to be higher in the rotation group compared to the nonrotation group (23.5 ± 14.7 vs 14.6 ± 12.8 mm−1; P = .05). No statistically significant differences were found for the mean values of tortuosity, curvature, torsion, or diameter between the 2 groups. Conclusion: Stent graft rotation occurred in 36% of the cases considered in this study. Cases with high iliac artery total net torsion were found to be more likely to have stent graft rotation upon deployment. This retrospective study provides a framework for prospectively studying the influence of iliac artery geometric properties on fenestrated stent graft rotation.
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Affiliation(s)
- Matthew G. Doyle
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
- Division of Vascular Surgery, Department of Surgery, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
- Division of Vascular Surgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Sean A. Crawford
- Division of Vascular Surgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Elrasheed Osman
- Division of Vascular Surgery, Department of Surgery, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
| | - Naomi Eisenberg
- Division of Vascular Surgery, Department of Surgery, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
| | - Leonard W. Tse
- Division of Vascular Surgery, Department of Surgery, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
- Division of Vascular Surgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Cristina H. Amon
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Thomas L. Forbes
- Division of Vascular Surgery, Department of Surgery, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada
- Division of Vascular Surgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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28
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Domagała Z, Stępak H, Drapikowski P, Kociemba A, Pyda M, Karmelita-Katulska K, Dzieciuchowicz Ł, Oszkinis G. Geometric verification of the validity of Finite Element Method analysis of Abdominal Aortic Aneurysms based on Magnetic Resonance Imaging. Biocybern Biomed Eng 2018. [DOI: 10.1016/j.bbe.2018.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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Farotto D, Segers P, Meuris B, Vander Sloten J, Famaey N. The role of biomechanics in aortic aneurysm management: requirements, open problems and future prospects. J Mech Behav Biomed Mater 2018; 77:295-307. [DOI: 10.1016/j.jmbbm.2017.08.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 12/18/2022]
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Kemmerling EMC, Peattie RA. Abdominal Aortic Aneurysm Pathomechanics: Current Understanding and Future Directions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1097:157-179. [DOI: 10.1007/978-3-319-96445-4_8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Bersi MR, Bellini C, Di Achille P, Humphrey JD, Genovese K, Avril S. Novel Methodology for Characterizing Regional Variations in the Material Properties of Murine Aortas. J Biomech Eng 2017; 138:2525708. [PMID: 27210500 DOI: 10.1115/1.4033674] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Indexed: 01/06/2023]
Abstract
Many vascular disorders, including aortic aneurysms and dissections, are characterized by localized changes in wall composition and structure. Notwithstanding the importance of histopathologic changes that occur at the microstructural level, macroscopic manifestations ultimately dictate the mechanical functionality and structural integrity of the aortic wall. Understanding structure-function relationships locally is thus critical for gaining increased insight into conditions that render a vessel susceptible to disease or failure. Given the scarcity of human data, mouse models are increasingly useful in this regard. In this paper, we present a novel inverse characterization of regional, nonlinear, anisotropic properties of the murine aorta. Full-field biaxial data are collected using a panoramic-digital image correlation (p-DIC) system. An inverse method, based on the principle of virtual power (PVP), is used to estimate values of material parameters regionally for a microstructurally motivated constitutive relation. We validate our experimental-computational approach by comparing results to those from standard biaxial testing. The results for the nondiseased suprarenal abdominal aorta from apolipoprotein-E null mice reveal material heterogeneities, with significant differences between dorsal and ventral as well as between proximal and distal locations, which may arise in part due to differential perivascular support and localized branches. Overall results were validated for both a membrane and a thick-wall model that delineated medial and adventitial properties. Whereas full-field characterization can be useful in the study of normal arteries, we submit that it will be particularly useful for studying complex lesions such as aneurysms, which can now be pursued with confidence given the present validation.
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Huang Y, Teng Z, Elkhawad M, Tarkin JM, Joshi N, Boyle JR, Buscombe JR, Fryer TD, Zhang Y, Park AY, Wilkinson IB, Newby DE, Gillard JH, Rudd JHF. High Structural Stress and Presence of Intraluminal Thrombus Predict Abdominal Aortic Aneurysm 18F-FDG Uptake: Insights From Biomechanics. Circ Cardiovasc Imaging 2017; 9:CIRCIMAGING.116.004656. [PMID: 27903534 PMCID: PMC5113243 DOI: 10.1161/circimaging.116.004656] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 09/19/2016] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Background— Abdominal aortic aneurysm (AAA) wall inflammation and mechanical structural stress may influence AAA expansion and lead to rupture. We hypothesized a positive correlation between structural stress and fluorine-18-labeled 2-deoxy-2-fluoro-d-glucose (18F-FDG) positron emission tomography–defined inflammation. We also explored the influence of computed tomography–derived aneurysm morphology and composition, including intraluminal thrombus, on both variables. Methods and Results— Twenty-one patients (19 males) with AAAs below surgical threshold (AAA size was 4.10±0.54 cm) underwent 18F-FDG positron emission tomography and contrast-enhanced computed tomography imaging. Structural stresses were calculated using finite element analysis. The relationship between maximum aneurysm 18F-FDG standardized uptake value within aortic wall and wall structural stress, patient clinical characteristics, aneurysm morphology, and compositions was explored using a hierarchical linear mixed-effects model. On univariate analysis, local aneurysm diameter, thrombus burden, extent of calcification, and structural stress were all associated with 18F-FDG uptake (P<0.05). AAA structural stress correlated with 18F-FDG maximum standardized uptake value (slope estimate, 0.552; P<0.0001). Multivariate linear mixed-effects analysis revealed an important interaction between structural stress and intraluminal thrombus in relation to maximum standardized uptake value (fixed effect coefficient, 1.68 [SE, 0.10]; P<0.0001). Compared with other factors, structural stress was the best predictor of inflammation (receiver-operating characteristic curve area under the curve =0.59), with higher accuracy seen in regions with high thrombus burden (area under the curve =0.80). Regions with both high thrombus burden and high structural stress had higher 18F-FDG maximum standardized uptake value compared with regions with high thrombus burdens but low stress (median [interquartile range], 1.93 [1.60–2.14] versus 1.14 [0.90–1.53]; P<0.0001). Conclusions— Increased aortic wall inflammation, demonstrated by 18F-FDG positron emission tomography, was observed in AAA regions with thick intraluminal thrombus subjected to high mechanical stress, suggesting a potential mechanistic link underlying aneurysm inflammation.
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Affiliation(s)
- Yuan Huang
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Zhongzhao Teng
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.).
| | - Maysoon Elkhawad
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Jason M Tarkin
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Nikhil Joshi
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Jonathan R Boyle
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - John R Buscombe
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Timothy D Fryer
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Yongxue Zhang
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Ah Yeon Park
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Ian B Wilkinson
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - David E Newby
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - Jonathan H Gillard
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.)
| | - James H F Rudd
- From the Department of Radiology (Y.H., Z.T., Y.Z., J.H.G.), EPSRC Centre for Mathematical and Statistical Analysis of Multimodal Clinical Imaging (Y.H.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (M.E., J.M.T., I.B.W., J.H.F.R.), Wolfson Brain Imaging Centre (T.D.F.), and Statistical Laboratory (A.Y.P.), University of Cambridge, United Kingdom; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, United Kingdom (N.J., D.E.N.); Department of Vascular Surgery (J.R. Boyle) and Department of Nuclear Medicine (J.R. Buscombe), Addenbrooke's Hospital, Cambridge, United Kingdom; and Department of Vascular Surgery, Changhai Hospital, Shanghai, China (Y.Z.).
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Pancheri FQ, Peattie RA, Reddy ND, Ahamed T, Lin W, Ouellette TD, Iafrati MD, Luis Dorfmann A. Histology and Biaxial Mechanical Behavior of Abdominal Aortic Aneurysm Tissue Samples. J Biomech Eng 2017; 139:2588203. [DOI: 10.1115/1.4035261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 12/20/2022]
Abstract
Abdominal aortic aneurysms (AAAs) represent permanent, localized dilations of the abdominal aorta that can be life-threatening if progressing to rupture. Evaluation of risk of rupture depends on understanding the mechanical behavior of patient AAA walls. In this project, a series of patient AAA wall tissue samples have been evaluated through a combined anamnestic, mechanical, and histopathologic approach. Mechanical properties of the samples have been characterized using a novel, strain-controlled, planar biaxial testing protocol emulating the in vivo deformation of the aorta. Histologically, the tissue ultrastructure was highly disrupted. All samples showed pronounced mechanical stiffening with stretch and were notably anisotropic, with greater stiffness in the circumferential than the axial direction. However, there were significant intrapatient variations in wall stiffness and stress. In biaxial tests in which the longitudinal stretch was held constant at 1.1 as the circumferential stretch was extended to 1.1, the maximum average circumferential stress was 330 ± 70 kPa, while the maximum average axial stress was 190 ± 30 kPa. A constitutive model considering the wall as anisotropic with two preferred directions fit the measured data well. No statistically significant differences in tissue mechanical properties were found based on patient gender, age, maximum bulge diameter, height, weight, body mass index, or smoking history. Although a larger patient cohort is merited to confirm these conclusions, the project provides new insight into the relationships between patient natural history, histopathology, and mechanical behavior that may be useful in the development of accurate methods for rupture risk evaluation.
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Affiliation(s)
| | - Robert A. Peattie
- Department of Surgery, Tufts Medical Center, Boston, MA 02111 e-mail:
| | - Nithin D. Reddy
- Department of Surgery, Tufts Medical Center, Boston, MA 02111
| | - Touhid Ahamed
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155
| | - Wenjian Lin
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155
| | | | - Mark D. Iafrati
- Department of Surgery, Tufts Medical Center, Boston, MA 02111
| | - A. Luis Dorfmann
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155; Department of Biomedical Engineering, Tufts University, Medford, MA 02155
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34
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Mechanical characterization of biological tissues: Experimental methods based on mathematical modeling. Biomed Eng Lett 2016. [DOI: 10.1007/s13534-016-0222-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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35
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Hollis L, Conlisk N, Thomas-Seale LEJ, Roberts N, Pankaj P, Hoskins PR. Computational simulations of MR elastography in idealised abdominal aortic aneurysms. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/4/045016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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36
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Volume growth of abdominal aortic aneurysms correlates with baseline volume and increasing finite element analysis-derived rupture risk. J Vasc Surg 2016; 63:1434-1442.e3. [DOI: 10.1016/j.jvs.2015.11.051] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 11/20/2015] [Indexed: 11/19/2022]
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37
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Gasser TC. Biomechanical Rupture Risk Assessment: A Consistent and Objective Decision-Making Tool for Abdominal Aortic Aneurysm Patients. AORTA : OFFICIAL JOURNAL OF THE AORTIC INSTITUTE AT YALE-NEW HAVEN HOSPITAL 2016; 4:42-60. [PMID: 27757402 DOI: 10.12945/j.aorta.2015.15.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/04/2016] [Indexed: 12/20/2022]
Abstract
Abdominal aortic aneurysm (AAA) rupture is a local event in the aneurysm wall that naturally demands tools to assess the risk for local wall rupture. Consequently, global parameters like the maximum diameter and its expansion over time can only give very rough risk indications; therefore, they frequently fail to predict individual risk for AAA rupture. In contrast, the Biomechanical Rupture Risk Assessment (BRRA) method investigates the wall's risk for local rupture by quantitatively integrating many known AAA rupture risk factors like female sex, large relative expansion, intraluminal thrombus-related wall weakening, and high blood pressure. The BRRA method is almost 20 years old and has progressed considerably in recent years, it can now potentially enrich the diameter indication for AAA repair. The present paper reviews the current state of the BRRA method by summarizing its key underlying concepts (i.e., geometry modeling, biomechanical simulation, and result interpretation). Specifically, the validity of the underlying model assumptions is critically disused in relation to the intended simulation objective (i.e., a clinical AAA rupture risk assessment). Next, reported clinical BRRA validation studies are summarized, and their clinical relevance is reviewed. The BRRA method is a generic, biomechanics-based approach that provides several interfaces to incorporate information from different research disciplines. As an example, the final section of this review suggests integrating growth aspects to (potentially) further improve BRRA sensitivity and specificity. Despite the fact that no prospective validation studies are reported, a significant and still growing body of validation evidence suggests integrating the BRRA method into the clinical decision-making process (i.e., enriching diameter-based decision-making in AAA patient treatment).
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Affiliation(s)
- T Christian Gasser
- KTH Royal Institute of Technology, KTH Solid Mechanics, Stockholm, Sweden
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Doyle BJ, Miller K, Newby DE, Hoskins PR. Commentary: Computational Biomechanics–Based Rupture Prediction of Abdominal Aortic Aneurysms. J Endovasc Ther 2016; 23:121-4. [DOI: 10.1177/1526602815615821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Barry J. Doyle
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Scotland, UK
| | - Karol Miller
- Vascular Engineering, Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
- Institute of Mechanics and Advanced Materials, Cardiff University, Cardiff, Wales, UK
| | - David E. Newby
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Scotland, UK
- Clinical Research Imaging Centre, University of Edinburgh, Scotland, UK
| | - Peter R. Hoskins
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Scotland, UK
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Volokh KY, Aboudi J. Aneurysm strength can decrease under calcification. J Mech Behav Biomed Mater 2015; 57:164-74. [PMID: 26717251 DOI: 10.1016/j.jmbbm.2015.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/04/2015] [Accepted: 11/11/2015] [Indexed: 12/18/2022]
Abstract
Aneurysms are abnormal dilatations of vessels in the vascular system that are prone to rupture. Prediction of the aneurysm rupture is a challenging and unsolved problem. Various factors can lead to the aneurysm rupture and, in the present study, we examine the effect of calcification on the aneurysm strength by using micromechanical modeling. The calcified tissue is considered as a composite material in which hard calcium particles are embedded in a hyperelastic soft matrix. Three experimentally calibrated constitutive models incorporating a failure description are used for the matrix representation. Two constitutive models describe the aneurysmal arterial wall and the third one - the intraluminal thrombus. The stiffness and strength of the calcified tissue are simulated in uniaxial tension under the varying amount of calcification, i.e. the relative volume of the hard inclusion within the periodic unit cell. In addition, the triaxiality of the stress state, which can be a trigger for the cavitation instability, is tracked. Results of the micromechanical simulation show an increase of the stiffness and a possible decrease of the strength of the calcified tissue as compared to the non-calcified one. The obtained results suggest that calcification (i.e. the presence of hard particles) can significantly affect the stiffness and strength of soft tissue. The development of refined experimental techniques that will allow for the accurate quantitative assessment of calcification is desirable.
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Affiliation(s)
| | - Jacob Aboudi
- Faculty of Engineering, Tel Aviv University, Israel.
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Volokh K. Thrombus rupture via cavitation. J Biomech 2015; 48:2186-8. [DOI: 10.1016/j.jbiomech.2015.04.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 04/30/2015] [Accepted: 04/30/2015] [Indexed: 11/17/2022]
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Gindre J, Bel-Brunon A, Kaladji A, Duménil A, Rochette M, Lucas A, Haigron P, Combescure A. Finite element simulation of the insertion of guidewires during an EVAR procedure: example of a complex patient case, a first step toward patient-specific parameterized models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015; 31:e02716. [PMID: 25820933 DOI: 10.1002/cnm.2716] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/20/2015] [Indexed: 06/04/2023]
Abstract
Deformations of the vascular structure due to the insertion of tools during endovascular treatment of aneurysms of the abdominal aorta, unless properly anticipated during the preoperative planning phase, may be the source of intraoperative or postoperative complications. We propose here an explicit finite element simulation method which enables one to predict such deformations. This method is based on a mechanical model of the vascular structure which takes into account the nonlinear behavior of the arterial wall, the prestressing effect induced by the blood pressure and the mechanical support of the surrounding organs and structures. An analysis of the model sensitivity to the parameters used to represent this environment is done. This allows determining the parameters that have the largest influence on the quality of the prediction and also provides realistic values for each of them as no experimental data are available in the literature. Moreover, for the first time, the results are compared with 3D intraoperative data. This is done for a patient-specific case with a complex anatomy in order to assess the feasibility of the method. Finally, the predictive capability of the simulation is evaluated on a group of nine patients. The error between the final simulated and intraoperatively measured tool positions was 2.1 mm after the calibration phase on one patient. It results in a 4.6 ± 2.5 mm in average error for the blind evaluation on nine patients.
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Affiliation(s)
- Juliette Gindre
- Université de Lyon, Lyon, F-69000, France
- LaMCoS CNRS UMR5259, INSA-Lyon, Villeurbanne, F-69621, France
- INSERM U1099, Rennes, F-35000, France
- LTSI, Université de Rennes 1, Rennes, F-35000, France
- ANSYS, Villeurbanne, F-69100, France
| | - Aline Bel-Brunon
- Université de Lyon, Lyon, F-69000, France
- LaMCoS CNRS UMR5259, INSA-Lyon, Villeurbanne, F-69621, France
| | - Adrien Kaladji
- INSERM U1099, Rennes, F-35000, France
- LTSI, Université de Rennes 1, Rennes, F-35000, France
- Department of Vascular Surgery, CHU Rennes, Rennes, F-35000, France
| | - Aurélien Duménil
- INSERM U1099, Rennes, F-35000, France
- LTSI, Université de Rennes 1, Rennes, F-35000, France
- THERENVA, Rennes, F-35000, France
| | | | - Antoine Lucas
- INSERM U1099, Rennes, F-35000, France
- LTSI, Université de Rennes 1, Rennes, F-35000, France
- Department of Vascular Surgery, CHU Rennes, Rennes, F-35000, France
| | - Pascal Haigron
- INSERM U1099, Rennes, F-35000, France
- LTSI, Université de Rennes 1, Rennes, F-35000, France
| | - Alain Combescure
- Université de Lyon, Lyon, F-69000, France
- LaMCoS CNRS UMR5259, INSA-Lyon, Villeurbanne, F-69621, France
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Tong J, Holzapfel GA. Structure, Mechanics, and Histology of Intraluminal Thrombi in Abdominal Aortic Aneurysms. Ann Biomed Eng 2015; 43:1488-501. [DOI: 10.1007/s10439-015-1332-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/06/2015] [Indexed: 01/08/2023]
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Diameter-Related Variations of Geometrical, Mechanical, and Mass Fraction Data in the Anterior Portion of Abdominal Aortic Aneurysms. Eur J Vasc Endovasc Surg 2015; 49:262-70. [DOI: 10.1016/j.ejvs.2014.12.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/08/2014] [Indexed: 11/21/2022]
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Determining the influence of calcification on the failure properties of abdominal aortic aneurysm (AAA) tissue. J Mech Behav Biomed Mater 2015; 42:154-67. [DOI: 10.1016/j.jmbbm.2014.11.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/21/2014] [Accepted: 11/03/2014] [Indexed: 11/20/2022]
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Simsek FG, Kwon YW. Investigation of material modeling in fluid-structure interaction analysis of an idealized three-layered abdominal aorta: aneurysm initiation and fully developed aneurysms. J Biol Phys 2015; 41:173-201. [PMID: 25624113 DOI: 10.1007/s10867-014-9372-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 11/06/2014] [Indexed: 01/26/2023] Open
Abstract
Different material models for an idealized three-layered abdominal aorta are compared using computational techniques to study aneurysm initiation and fully developed aneurysms. The computational model includes fluid-structure interaction (FSI) between the blood vessel and the blood. In order to model aneurysm initiation, the medial region was degenerated to mimic the medial loss occurring in the inception of an aneurysm. Various cases are considered in order to understand their effects on the initiation of an abdominal aortic aneurysm. The layers of the blood vessel were modeled using either linear elastic materials or Mooney-Rivlin (otherwise known as hyperelastic) type materials. The degenerated medial region was also modeled in either linear elastic or hyperelastic-type materials and assumed to be in the shape of an arc with a thin width or a circular ring with different widths. The blood viscosity effect was also considered in the initiation mechanism. In addition, dynamic analysis of the blood vessel was performed without interaction with the blood flow by applying time-dependent pressure inside the lumen in a three-layered abdominal aorta. The stresses, strains, and displacements were compared for a healthy aorta, an initiated aneurysm and a fully developed aneurysm. The study shows that the material modeling of the vessel has a sizable effect on aneurysm initiation and fully developed aneurysms. Different material modeling of degeneration regions also affects the stress-strain response of aneurysm initiation. Additionally, the structural analysis without considering FSI (called noFSI) overestimates the peak von Mises stress by 52% at the interfaces of the layers.
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Affiliation(s)
- Fatma Gulden Simsek
- Institute of Biomedical Engineering, Bogazici University, Kandilli Camp, Istanbul, Turkey,
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Xenos M, Labropoulos N, Rambhia S, Alemu Y, Einav S, Tassiopoulos A, Sakalihasan N, Bluestein D. Progression of abdominal aortic aneurysm towards rupture: refining clinical risk assessment using a fully coupled fluid-structure interaction method. Ann Biomed Eng 2014; 43:139-53. [PMID: 25527320 DOI: 10.1007/s10439-014-1224-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/09/2014] [Indexed: 01/12/2023]
Abstract
Rupture of abdominal aortic aneurysm (AAA) is associated with high mortality rates. Risk of rupture is multi-factorial involving AAA geometric configuration, vessel tortuosity, and the presence of intraluminal pathology. Fluid structure interaction (FSI) simulations were conducted in patient based computed tomography scans reconstructed geometries in order to monitor aneurysmal disease progression from normal aortas to non-ruptured and contained ruptured AAA (rAAA), and the AAA risk of rupture was assessed. Three groups of 8 subjects each were studied: 8 normal and 16 pathological (8 non-ruptured and 8 rAAA). The AAA anatomical structures segmented included the blood lumen, intraluminal thrombus (ILT), vessel wall, and embedded calcifications. The vessel wall was described with anisotropic material model that was matched to experimental measurements of AAA tissue specimens. A statistical model for estimating the local wall strength distribution was employed to generate a map of a rupture potential index (RPI), representing the ratio between the local stress and local strength distribution. The FSI simulations followed a clear trend of increasing wall stresses from normal to pathological cases. The maximal stresses were observed in the areas where the ILT was not present, indicating a potential protective effect of the ILT. Statistically significant differences were observed between the peak systolic stress and the peak stress at the mean arterial pressure between the three groups. For the ruptured aneurysms, where the geometry of intact aneurysm was reconstructed, results of the FSI simulations clearly depicted maximum wall stress at the a priori known location of rupture. The RPI mapping indicated several distinct regions of high RPI coinciding with the actual location of rupture. The FSI methodology demonstrates that the aneurysmal disease can be described by numerical simulations, as indicated by a clear trend of increasing aortic wall stresses in the studied groups, (normal aortas, AAAs and rAAAs). Ultimately, the results demonstrate that FSI wall stress mapping and RPI can be used as a tool for predicting the potential rupture of an AAA by predicting the actual rupture location, complementing current clinical practice by offering a predictive diagnostic tool for deciding whether to intervene surgically or spare the patient from an unnecessary risky operation.
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Affiliation(s)
- Michalis Xenos
- Department of Mathematics, University of Ioannina, Ioannina, Greece
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Lederman A, Saliture Neto FT, Ferreira R, de Figueiredo LFP, Otoch JP, Aun R, da Silva ES. Endovascular model of abdominal aortic aneurysm induction in swine. Vasc Med 2014; 19:167-174. [DOI: 10.1177/1358863x14534006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Abdominal aortic aneurysms are among the main causes of death. The high morbidity and mortality associated with aneurysm rupture and repair represents a challenge for surgeons and high risk for patients. Although experimental models are useful to understand, train, and develop new treatment and diagnostic methods for this pathology, animal models developed to date are far from ideal. Animals are either too small and do not represent the pathology of humans, or the procedures employ laparotomy, or the aortic behavior does not resemble that of a true aneurysm. We developed a novel, less invasive and effective method to induce true aortic aneurysms in Large White pigs. Animals were submitted to an endovascular chemical induction using either calcium chloride (25%) or swine pancreatic elastase. Controls were exposed to saline solution. All animals were operated on using the same surgical technique under general anesthesia. They were followed weekly with ultrasound examinations and at 4 weeks the aorta was harvested. Although elastase induced only arterial dilation, imaging, histological, and biomechanical studies of the aorta revealed the formation of true aneurysms in animals exposed to calcium chloride. Aneurysms in the latter group had biomechanical failure properties similar to those of human aneurysms. These findings indicate that the endovascular approach is viable and does not cause retroperitoneal fibrosis.
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Affiliation(s)
- Alex Lederman
- Vascular Surgery, Hospital Universitário, Universidade de São Paulo (USP), São Paulo, Brazil
- Vascular Surgery, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | | | - Rimarcs Ferreira
- Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Jose Pinhata Otoch
- Surgical Techniques, Faculdade de Medicina da Universidade de São Paulo (USP), São Paulo, Brazil
| | - Ricardo Aun
- Vascular Surgery, Hospital Israelita Albert Einstein, São Paulo, Brazil
- Vascular Surgery, Faculdade de Medicina da Universidade de São Paulo (USP), São Paulo, Brazil
| | - Erasmo Simão da Silva
- Vascular Surgery, Faculdade de Medicina da Universidade de São Paulo (USP), São Paulo, Brazil
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Gong L, Chen J, Lu J, Fan L, Huang J, Zhang Y, Lv B, Hui R, Wang Y. The 9p21 locus is associated with coronary artery disease and cardiovascular events in the presence (but not in the absence) of coronary calcification. PLoS One 2014; 9:e94823. [PMID: 24732910 PMCID: PMC3986239 DOI: 10.1371/journal.pone.0094823] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Accepted: 03/20/2014] [Indexed: 11/26/2022] Open
Abstract
Variants at the 9p21 locus have been associated with coronary artery disease (CAD); coronary artery calcification (CAC) is related to CAD and other cardiovascular events. To determine the association of the 9p21 locus with CAD in the presence and absence of CAC, 4 groups were enrolled in a case-control study, including 527 CAD patients without CAC, 692 CAD patients with CAC, 585 individuals with simple CAC but no CAD, and 725 healthy controls. The rs1333049 representing the locus was associated with CAD in the presence of CAC (odds ratio = 1.38 in allelic analysis, 95%CI, 1.19–1.60, P<0.001), but not in the absence of CAC. Additionally, rs1333049 was not associated with simple CAC or CAC severity/extent in CAD patients with CAC. 849 CAD patients undergoing revascularization (660 with CAC and 189 without CAC) were enrolled in a cohort study to test its association with cardiovascular events in CAD patients with and without CAC in a 3-year follow-up. rs1333049 was significantly associated with the incidence of cardiovascular events in non-target vessels in patients with CAC (hazard ratio = 1.44, 95%CI, 1.08–1.91, P = 0.012), but not in those without CAC. The variants at the 9p21 locus were related to CAD and post-revascularization events only in the presence of CAC, suggesting that they may confer risk of calcification-related coronary atherosclerosis.
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Affiliation(s)
- Ling Gong
- State Key Laboratory of Cardiovascular Disease, Sino-German Laboratory for Molecular Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jinxing Chen
- State Key Laboratory of Cardiovascular Disease, Sino-German Laboratory for Molecular Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jinguo Lu
- Department of Radiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lizi Fan
- Departement of Medical Ultrasonic, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jinghan Huang
- Heart Function Testing Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu Zhang
- State Key Laboratory of Cardiovascular Disease, Sino-German Laboratory for Molecular Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bin Lv
- Department of Radiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Rutai Hui
- State Key Laboratory of Cardiovascular Disease, Sino-German Laboratory for Molecular Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- * E-mail: (RH); (YW)
| | - Yibo Wang
- State Key Laboratory of Cardiovascular Disease, Sino-German Laboratory for Molecular Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- * E-mail: (RH); (YW)
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Cloonan AJ, Shahmirzadi D, Li RX, Doyle BJ, Konofagou EE, McGloughlin TM. 3D-Printed Tissue-Mimicking Phantoms for Medical Imaging and Computational Validation Applications. 3D PRINTING AND ADDITIVE MANUFACTURING 2014; 1:14-23. [PMID: 28804733 PMCID: PMC4981152 DOI: 10.1089/3dp.2013.0010] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Abdominal aortic aneurysm (AAA) is a permanent, irreversible dilation of the distal region of the aorta. Recent efforts have focused on improved AAA screening and biomechanics-based failure prediction. Idealized and patient-specific AAA phantoms are often employed to validate numerical models and imaging modalities. To produce such phantoms, the investment casting process is frequently used, reconstructing the 3D vessel geometry from computed tomography patient scans. In this study the alternative use of 3D printing to produce phantoms is investigated. The mechanical properties of flexible 3D-printed materials are benchmarked against proven elastomers. We demonstrate the utility of this process with particular application to the emerging imaging modality of ultrasound-based pulse wave imaging, a noninvasive diagnostic methodology being developed to obtain regional vascular wall stiffness properties, differentiating normal and pathologic tissue in vivo. Phantom wall displacements under pulsatile loading conditions were observed, showing good correlation to fluid-structure interaction simulations and regions of peak wall stress predicted by finite element analysis. 3D-printed phantoms show a strong potential to improve medical imaging and computational analysis, potentially helping bridge the gap between experimental and clinical diagnostic tools.
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Affiliation(s)
- Aidan J. Cloonan
- Centre for Applied Biomedical Engineering Research, Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick, Ireland
- Irish Centre for Composites Research, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
- Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Danial Shahmirzadi
- Ultrasound and Elasticity Imaging Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | - Ronny X. Li
- Ultrasound and Elasticity Imaging Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York
| | - Barry J. Doyle
- Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, University of Western Australia, Perth, Australia
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Elisa E. Konofagou
- Ultrasound and Elasticity Imaging Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York
- Department of Radiology, Columbia University, New York, New York
| | - Tim M. McGloughlin
- Centre for Applied Biomedical Engineering Research, Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick, Limerick, Ireland
- Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
- Department of Biomedical Engineering, Khalifa University of Science, Technology & Research, Abu Dhabi, United Arab Emirates
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50
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Shang EK, Lai E, Pouch AM, Hinmon R, Gorman RC, Gorman JH, Sehgal CM, Ferrari G, Bavaria JE, Jackson BM. Validation of semiautomated and locally resolved aortic wall thickness measurements from computed tomography. J Vasc Surg 2014; 61:1034-40. [PMID: 24388698 DOI: 10.1016/j.jvs.2013.11.065] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 11/07/2013] [Accepted: 11/19/2013] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Aortic wall thickness (AWT) is important for anatomic description and biomechanical modeling of aneurysmal disease. However, no validated, noninvasive method for measuring AWT exists. We hypothesized that semiautomated image segmentation algorithms applied to computed tomography angiography (CTA) can accurately measure AWT. METHODS Aortic samples from 10 patients undergoing open thoracoabdominal aneurysm repair were taken from sites of the proximal or distal anastomosis, or both, yielding 13 samples. Aortic specimens were fixed in formalin, embedded in paraffin, and sectioned. After staining with hematoxylin and eosin and Masson's trichrome, sections were digitally scanned and measured. Patients' preoperative CTA Digital Imaging and Communications in Medicine (DICOM; National Electrical Manufacturers Association, Rosslyn, Va) images were segmented into luminal, inner arterial, and outer arterial surfaces with custom algorithms using active contours, isoline contour detection, and texture analysis. AWT values derived from image data were compared with measurements of corresponding pathologic specimens. RESULTS AWT determined by CTA averaged 2.33 ± 0.66 mm (range, 1.52-3.55 mm), and the AWT of pathologic specimens averaged 2.36 ± 0.75 mm (range, 1.51-4.16 mm). The percentage difference between pathologic specimens and CTA-determined AWT was 9.5% ± 4.1% (range, 1.8%-16.7%). The correlation between image-based measurements and pathologic measurements was high (R = 0.935). The 95% limits of agreement computed by Bland-Altman analysis fell within the range of -0.42 and 0.42 mm. CONCLUSIONS Semiautomated analysis of CTA images can be used to accurately measure regional and patient-specific AWT, as validated using pathologic ex vivo human aortic specimens. Descriptions and reconstructions of aortic aneurysms that incorporate locally resolved wall thickness are feasible and may improve future attempts at biomechanical analyses.
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Affiliation(s)
- Eric K Shang
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Eric Lai
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Cardiac Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Alison M Pouch
- Division of Ultrasound Research, Department of Radiology, University of Pennsylvania, Philadelphia, Pa
| | - Robin Hinmon
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Cardiac Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Robert C Gorman
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Cardiac Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Joseph H Gorman
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Cardiac Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Chandra M Sehgal
- Division of Ultrasound Research, Department of Radiology, University of Pennsylvania, Philadelphia, Pa
| | - Giovanni Ferrari
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Cardiac Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Joseph E Bavaria
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Cardiac Surgery, University of Pennsylvania, Philadelphia, Pa
| | - Benjamin M Jackson
- Department of Surgery, University of Pennsylvania, Philadelphia, Pa; Division of Vascular Surgery and Endovascular Therapy, University of Pennsylvania, Philadelphia, Pa.
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