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Schoenborn S, Lorenz T, Kuo K, Fletcher DF, Woodruff MA, Pirola S, Allenby MC. Fluid-structure interactions of peripheral arteries using a coupled in silico and in vitro approach. Comput Biol Med 2023; 165:107474. [PMID: 37703711 DOI: 10.1016/j.compbiomed.2023.107474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/21/2023] [Accepted: 09/04/2023] [Indexed: 09/15/2023]
Abstract
Vascular compliance is considered both a cause and a consequence of cardiovascular disease and a significant factor in the mid- and long-term patency of vascular grafts. However, the biomechanical effects of localised changes in compliance cannot be satisfactorily studied with the available medical imaging technologies or surgical simulation materials. To address this unmet need, we developed a coupled silico-vitro platform which allows for the validation of numerical fluid-structure interaction results as a numerical model and physical prototype. This numerical one-way and two-way fluid-structure interaction study is based on a three-dimensional computer model of an idealised femoral artery which is validated against patient measurements derived from the literature. The numerical results are then compared with experimental values collected from compliant arterial phantoms via direct pressurisation and ring tensile testing. Phantoms within a compliance range of 1.4-68.0%/100 mmHg were fabricated via additive manufacturing and silicone casting, then mechanically characterised via ring tensile testing and optical analysis under direct pressurisation with moderately statistically significant differences in measured compliance ranging between 10 and 20% for the two methods. One-way fluid-structure interaction coupling underestimated arterial wall compliance by up to 14.7% compared with two-way coupled models. Overall, Solaris™ (Smooth-On) matched the compliance range of the numerical and in vivo patient models most closely out of the tested silicone materials. Our approach is promising for vascular applications where mechanical compliance is especially important, such as the study of diseases which commonly affect arterial wall stiffness, such as atherosclerosis, and the model-based design, surgical training, and optimisation of vascular prostheses.
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Affiliation(s)
- S Schoenborn
- BioMimetic Systems Engineering (BMSE) Lab, School of Chemical Engineering, University of Queensland (UQ), St Lucia, QLD, 4072, Australia; Biofabrication and Tissue Morphology (BTM) Group, Faculty of Engineering, Centre for Biomedical Technologies, Queensland University of Technology (QUT), Kelvin Grove, QLD, 4059, Australia
| | - T Lorenz
- Institute of Textile Technology, RWTH Aachen University, 52074, Aachen, Germany
| | - K Kuo
- Institute of Textile Technology, RWTH Aachen University, 52074, Aachen, Germany
| | - D F Fletcher
- School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, NSW, 2006, Australia
| | - M A Woodruff
- Biofabrication and Tissue Morphology (BTM) Group, Faculty of Engineering, Centre for Biomedical Technologies, Queensland University of Technology (QUT), Kelvin Grove, QLD, 4059, Australia
| | - S Pirola
- BHF Centre of Research Excellence, Faculty of Medicine, Institute of Clinical Sciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom; Department of Biomechanical Engineering, Faculty of Mechanical Engineering (3me), Delft University of Technology (TUD), Delft, the Netherlands
| | - M C Allenby
- BioMimetic Systems Engineering (BMSE) Lab, School of Chemical Engineering, University of Queensland (UQ), St Lucia, QLD, 4072, Australia; Biofabrication and Tissue Morphology (BTM) Group, Faculty of Engineering, Centre for Biomedical Technologies, Queensland University of Technology (QUT), Kelvin Grove, QLD, 4059, Australia.
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Dos Santos FJ, Hernandez BA, Santos R, Machado M, Souza M, Capello Sousa EA, Andrade A. Bioabsorbable Polymeric Stent for the Treatment of Coarctation of the Aorta (CoA) in Children: A Methodology to Evaluate the Design and Mechanical Properties of PLA Polymer. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4403. [PMID: 37374585 DOI: 10.3390/ma16124403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/26/2023] [Accepted: 05/11/2023] [Indexed: 06/29/2023]
Abstract
This study presents a methodology that combines experimental tests and the finite element method, which is able to analyse the influence of the geometry on the mechanical behaviour of stents made of bioabsorbable polymer PLA (PolyLactic Acid) during their expansion in the treatment of coarctation of the aorta (CoA). Tensile tests with standardized specimen samples were conducted to determine the properties of a 3D-printed PLA. A finite element model of a new stent prototype was generated from CAD files. A rigid cylinder simulating the expansion balloon was also created to simulate the stent opening performance. A tensile test with 3D-printed customized stent specimens was performed to validate the FE stent model. Stent performance was evaluated in terms of elastic return, recoil, and stress levels. The 3D-printed PLA presented an elastic modulus of 1.5 GPa and a yield strength of 30.6 MPa, lower than non-3D-printed PLA. It can also be inferred that crimping had little effect on stent circular recoil performance, as the difference between the two scenarios was on average 1.81%. For an expansion of diameters ranging from 12 mm to 15 mm, as the maximum opening diameter increases, the recoil levels decrease, ranging from 10 to 16.75% within the reported range. These results point out the importance of testing the 3D-printed PLA under the conditions of using it to access its material properties; the results also indicate that the crimping process could be disregarded in simulations to obtain fast results with lower computational cost and that new proposed stent geometry made of PLA might be suitable for use in CoA treatments-the approach that has not been applied before. The next steps will be to simulate the opening of an aorta vessel using this geometry.
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Affiliation(s)
- Flávio José Dos Santos
- Department of Mechanical Engineering, Centre for Simulation in Bioengineering, Biomechanics and Biomaterials, School of Engineering (CS3B), Campus of Bauru, UNESP-São Paulo State University, São Paulo 17033-360, Brazil
| | - Bruno Agostinho Hernandez
- Department of Mechanical Engineering, Centre for Simulation in Bioengineering, Biomechanics and Biomaterials, School of Engineering (CS3B), Campus of Bauru, UNESP-São Paulo State University, São Paulo 17033-360, Brazil
| | - Rosana Santos
- Department of Engineering, PUC-Pontifical Catholic University of São Paulo, São Paulo 05014-901, Brazil
| | - Marcel Machado
- Department of Mechanical Engineering, Centre for Simulation in Bioengineering, Biomechanics and Biomaterials, School of Engineering (CS3B), Campus of Bauru, UNESP-São Paulo State University, São Paulo 17033-360, Brazil
| | - Mateus Souza
- Department of Mechanical Engineering, Centre for Simulation in Bioengineering, Biomechanics and Biomaterials, School of Engineering (CS3B), Campus of Bauru, UNESP-São Paulo State University, São Paulo 17033-360, Brazil
| | - Edson A Capello Sousa
- Department of Mechanical Engineering, Centre for Simulation in Bioengineering, Biomechanics and Biomaterials, School of Engineering (CS3B), Campus of Bauru, UNESP-São Paulo State University, São Paulo 17033-360, Brazil
| | - Aron Andrade
- CEAC-Centre for Engineering in Circulatory Assistance, Dante Pazzanese Institute of Cardiology, São Paulo 04012-909, Brazil
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Sengupta S, Yuan X, Maga L, Pirola S, Nienaber CA, Xu XY. Aortic haemodynamics and wall stress analysis following arch aneurysm repair using a single-branched endograft. Front Cardiovasc Med 2023; 10:1125110. [PMID: 37283581 PMCID: PMC10240084 DOI: 10.3389/fcvm.2023.1125110] [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: 12/15/2022] [Accepted: 05/08/2023] [Indexed: 06/08/2023] Open
Abstract
Introduction Thoracic endovascular aortic repair (TEVAR) of the arch is challenging given its complex geometry and the involvement of supra-aortic arteries. Different branched endografts have been designed for use in this region, but their haemodynamic performance and the risk for post-intervention complications are not yet clear. This study aims to examine aortic haemodynamics and biomechanical conditions following TVAR treatment of an aortic arch aneurysm with a two-component single-branched endograft. Methods Computational fluid dynamics and finite element analysis were applied to a patient-specific case at different stages: pre-intervention, post-intervention and follow-up. Physiologically accurate boundary conditions were used based on available clinical information. Results Computational results obtained from the post-intervention model confirmed technical success of the procedure in restoring normal flow to the arch. Simulations of the follow-up model, where boundary conditions were modified to reflect change in supra-aortic vessel perfusion observed on the follow-up scan, predicted normal flow patterns but high levels of wall stress (up to 1.3M MPa) and increased displacement forces in regions at risk of compromising device stability. This might have contributed to the suspected endoleaks or device migration identified at the final follow up. Discussion Our study demonstrated that detailed haemodynamic and biomechanical analysis can help identify possible causes for post-TEVAR complications in a patient-specific setting. Further refinement and validation of the computational workflow will allow personalised assessment to aid in surgical planning and clinical decision making.
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Affiliation(s)
- Sampad Sengupta
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Xun Yuan
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Cardiology and Aortic Centre, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Ludovica Maga
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
- Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands
| | - Selene Pirola
- Department of Biomechanical Engineering, Delft University of Technology, Delft, Netherlands
| | - Christoph A. Nienaber
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Cardiology and Aortic Centre, Royal Brompton and Harefield Hospitals, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
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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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Goodarzi Ardakani V, Goordoyal H, Ordonez MV, Sophocleous F, Curtis S, Bedair R, Caputo M, Gambaruto A, Biglino G. Isolating the Effect of Arch Architecture on Aortic Hemodynamics Late After Coarctation Repair: A Computational Study. Front Cardiovasc Med 2022; 9:855118. [PMID: 35811705 PMCID: PMC9263195 DOI: 10.3389/fcvm.2022.855118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
Objectives Effective management of aortic coarctation (CoA) affects long-term cardiovascular outcomes. Full appreciation of CoA hemodynamics is important. This study aimed to analyze the relationship between aortic shape and hemodynamic parameters by means of computational simulations, purposely isolating the morphological variable. Methods Computational simulations were run in three aortic models. MRI-derived aortic geometries were generated using a statistical shape modeling methodology. Starting from n = 108 patients, the mean aortic configuration was derived in patients without CoA (n = 37, "no-CoA"), with surgically repaired CoA (n = 58, "r-CoA") and with unrepaired CoA (n = 13, "CoA"). As such, the aortic models represented average configurations for each scenario. Key hemodynamic parameters (i.e., pressure drop, aortic velocity, vorticity, wall shear stress WSS, and length and number of strong flow separations in the descending aorta) were measured in the three models at three time points (peak systole, end systole, end diastole). Results Comparing no-CoA and CoA revealed substantial differences in all hemodynamic parameters. However, simulations revealed significant increases in vorticity at the site of CoA repair, higher WSS in the descending aorta and a 12% increase in power loss, in r-CoA compared to no-CoA, despite no clinically significant narrowing (CoA index >0.8) in the r-CoA model. Conclusions Small alterations in aortic morphology impact on key hemodynamic indices. This may contribute to explaining phenomena such as persistent hypertension in the absence of any clinically significant narrowing. Whilst cardiovascular events in these patients may be related to hypertension, the role of arch geometry may be a contributory factor.
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Affiliation(s)
| | - Harshinee Goordoyal
- Department of Mechanical Engineering, University of Bristol, Bristol, United Kingdom
| | | | - Froso Sophocleous
- University Hospitals Bristol and Weston, NHS Foundation Trust, Bristol, United Kingdom.,Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Stephanie Curtis
- University Hospitals Bristol and Weston, NHS Foundation Trust, Bristol, United Kingdom
| | - Radwa Bedair
- University Hospitals Bristol and Weston, NHS Foundation Trust, Bristol, United Kingdom
| | - Massimo Caputo
- University Hospitals Bristol and Weston, NHS Foundation Trust, Bristol, United Kingdom.,Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Alberto Gambaruto
- Department of Mechanical Engineering, University of Bristol, Bristol, United Kingdom
| | - Giovanni Biglino
- University Hospitals Bristol and Weston, NHS Foundation Trust, Bristol, United Kingdom.,Bristol Medical School, University of Bristol, Bristol, United Kingdom.,National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Kan X, Ma T, Lin J, Wang L, Dong Z, Xu XY. Patient-specific simulation of stent-graft deployment in type B aortic dissection: model development and validation. Biomech Model Mechanobiol 2021; 20:2247-2258. [PMID: 34431034 PMCID: PMC8595232 DOI: 10.1007/s10237-021-01504-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022]
Abstract
Thoracic endovascular aortic repair (TEVAR) has been accepted as the mainstream treatment for type B aortic dissection, but post-TEVAR biomechanical-related complications are still a major drawback. Unfortunately, the stent-graft (SG) configuration after implantation and biomechanical interactions between the SG and local aorta are usually unknown prior to a TEVAR procedure. The ability to obtain such information via personalised computational simulation would greatly assist clinicians in pre-surgical planning. In this study, a virtual SG deployment simulation framework was developed for the treatment for a complicated aortic dissection case. It incorporates patient-specific anatomical information based on pre-TEVAR CT angiographic images, details of the SG design and the mechanical properties of the stent wire, graft and dissected aorta. Hyperelastic material parameters for the aortic wall were determined based on uniaxial tensile testing performed on aortic tissue samples taken from type B aortic dissection patients. Pre-stress conditions of the aortic wall and the action of blood pressure were also accounted for. The simulated post-TEVAR configuration was compared with follow-up CT scans, demonstrating good agreement with mean deviations of 5.8% in local open area and 4.6 mm in stent strut position. Deployment of the SG increased the maximum principal stress by 24.30 kPa in the narrowed true lumen but reduced the stress by 31.38 kPa in the entry tear region where there was an aneurysmal expansion. Comparisons of simulation results with different levels of model complexity suggested that pre-stress of the aortic wall and blood pressure inside the SG should be included in order to accurately predict the deformation of the deployed SG.
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Affiliation(s)
- Xiaoxin Kan
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Tao Ma
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing Lin
- Key Laboratory of Textile Science and Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai, China
| | - Lu Wang
- Key Laboratory of Textile Science and Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
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