1
|
Liang M, Song L, Gao Y, Feng W, Wang L, Fan Y. Structural optimization of degradable polymer vascular stents based on surrogate models. Comput Methods Biomech Biomed Engin 2024:1-11. [PMID: 38937925 DOI: 10.1080/10255842.2024.2370400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 06/06/2024] [Indexed: 06/29/2024]
Abstract
The clinical performance of biodegradable polymer stents implanted in blood vessels is affected by uneven degradation. Stress distribution plays an important role in polymer degradation, and local stress concentration leads to the premature fracture of stents. Numerical simulations combined with in vitro experimental validation can accurately describe the degradation process and perform structural optimization. Compared with traditional design techniques, optimization based on surrogate models is more scientifically effective. Three stent structures were designed and optimized, with the effective working time during degradation as the optimization goal. The finite element method was employed to simulate the degradation process of the stent. Surrogate models were employed to establish the functional relationship between the design parameters and the degradation performance. The proposed function models accurately predicted the degradation performance of various stents. The optimized stent structures demonstrated improved degradation performance, with the kriging model showing a better optimization effect. This study provided a novel approach for optimizing the structural design of biodegradable polymer stents to enhance degradation performance.
Collapse
Affiliation(s)
- Mingkai Liang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Hangzhou International Innovation Institute, Beihang University, Hangzhou, China
| | - Lihua Song
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yuanming Gao
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Wentao Feng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Lizhen Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Hangzhou International Innovation Institute, Beihang University, Hangzhou, China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| |
Collapse
|
2
|
Li L, Zhu P, Li Q, Gao Y, Fan Y. Symmetrical structure design of PLGA Biodegradable sinus stents and structure optimization based on surrogate models. Comput Methods Biomech Biomed Engin 2024:1-10. [PMID: 38776383 DOI: 10.1080/10255842.2024.2355491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
This study aims to enhance the degradation uniformity of PLGA sinus stents to minimize fracture risk caused by stress corrosion. Symmetric stent structures were introduced and compared to sinusoidal structure in terms of stress and degradation uniformity during implantation and degradation processes. Three surrogate models were employed to optimize the honeycomb-like structure. Results showed honeycomb-like structures exhibited the superior stress distribution and highest degradation uniformity. The kriging model achieved the smallest error and degradation uniformity of 83.24%. In conclusion, enhancing the symmetry of stent structures improves degradation uniformity, and the kriging model has potential for the optimization of stent structures.
Collapse
Affiliation(s)
- Lingyan Li
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Peng Zhu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Qiao Li
- School of Engineering Medicine, Beihang University, Beijing, China
| | - Yuanming Gao
- School of Engineering Medicine, Beihang University, Beijing, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- School of Engineering Medicine, Beihang University, Beijing, China
| |
Collapse
|
3
|
Karimi A, Rahmati SM, Razaghi R, Girkin CA, Crawford Downs J. Finite element modeling of the complex anisotropic mechanical behavior of the human sclera and pia mater. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 215:106618. [PMID: 35026624 PMCID: PMC8847341 DOI: 10.1016/j.cmpb.2022.106618] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/31/2021] [Accepted: 01/01/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Accurate finite element (FE) simulation of the optic nerve head (ONH) depends on accurate mechanical properties of the load-bearing tissues. The peripapillary sclera in the ONH exhibits a depth-dependent, anisotropic, heterogeneous collagen fiber distribution. This study proposes a novel cable-in-solid modeling approach that mimics heterogeneous anisotropic collagen fiber distribution, validates the approach against published experimental biaxial tensile tests of scleral patches, and demonstrates its effectiveness in a complex model of the posterior human eye and ONH. METHODS A computational pipeline was developed that defines control points in the sclera and pia mater, distributes the depth-dependent circumferential, radial, and isotropic cable elements in the sclera and pia in a pattern that mimics collagen fiber orientation, and couples the cable elements and solid matrix using a mesh-free penalty-based cable-in-solid algorithm. A parameter study was performed on a model of a human scleral patch subjected to biaxial deformation, and computational results were matched to published experimental data. The new approach was incorporated into a previously published eye-specific model to test the method; results were then interpreted in relation to the collagen fibers' (cable elements) role in the resultant ONH deformations, stresses, and strains. RESULTS Results show that the cable-in-solid approach can mimic the full range of scleral mechanical behavior measured experimentally. Disregarding the collagen fibers/cable elements in the posterior eye model resulted in ∼20-60% greater tensile and shear stresses and strains, and ∼30% larger posterior deformations in the lamina cribrosa and peripapillary sclera. CONCLUSIONS The cable-in-solid approach can easily be implemented into commercial FE packages to simulate the heterogeneous and anisotropic mechanical properties of collagenous biological tissues.
Collapse
Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
| | | | - Reza Razaghi
- Research Department, Heel of Scene Ltd., Tokyo, Japan
| | - Christopher A Girkin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - J Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
4
|
Computational Analysis of Mechanical Performance for Composite Polymer Biodegradable Stents. MATERIALS 2021; 14:ma14206016. [PMID: 34683608 PMCID: PMC8539075 DOI: 10.3390/ma14206016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/03/2021] [Accepted: 10/08/2021] [Indexed: 11/20/2022]
Abstract
Bioresorbable stents (BRS) represent the latest generation of vascular scaffolds used for minimally invasive interventions. They aim to overcome the shortcomings of established bare-metal stents (BMS) and drug-eluting stents (DES). Recent advances in the field of bioprinting offer the possibility of combining biodegradable polymers to produce a composite BRS. Evaluation of the mechanical performance of the novel composite BRS is the focus of this study, based on the idea that they are a promising solution to improve the strength and flexibility performance of single material BRS. Finite element analysis of stent crimping and expansion was performed. Polylactic acid (PLA) and polycaprolactone (PCL) formed a composite stent divided into four layers, resulting in sixteen unique combinations. A comparison of the mechanical performance of the different composite configurations was performed. The resulting stresses, strains, elastic recoil, and foreshortening were evaluated and compared to existing experimental results. Similar behaviour was observed for material configurations that included at least one PLA layer. A pure PCL stent showed significant elastic recoil and less shortening compared to PLA and composite structures. The volumetric ratio of the materials was found to have a more significant effect on recoil and foreshortening than the arrangement of the material layers. Composite BRS offer the possibility of customising the mechanical behaviour of scaffolds. They also have the potential to support the fabrication of personalised or plaque-specific stents.
Collapse
|
5
|
PANNEERSELVAM NISANTHKUMAR, MUTHUSWAMY SREEKUMAR. DESIGN AND ANALYSIS OF NEW STENT PATTERNS FOR ENHANCED PERFORMANCE. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420500396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Deploying a stent to restore blood flow in the coronary artery is very complicated, as its internal diameter is smaller than 3[Formula: see text]mm. It has already been proven that mechanical stresses induced on stent and artery during deployment make the placement of stent very difficult, besides the development of complications due to artery damage. Various stent designs have already been developed, especially in the metallic category. Still, there are possibilities for developing new stent designs and patterns to overcome the complexities of the existing models. Also, the technology of metallic stents can be carried forward towards the development of bioresorbable polymeric stents. In this work, three new stent cell designs (curvature, diamond, and oval) have been proposed to obtain better performance and life. The finite element method is utilized to explore the mechanical behavior of stent expansion and determine the biomechanical stresses imposed on the stent and artery during the stenting procedure. The results obtained have been compared with the available literature and found that the curvature cell design develops lower stresses and, hence, be suitable for better performance and life.
Collapse
Affiliation(s)
- NISANTHKUMAR PANNEERSELVAM
- Department of Mechanical Engineering, Indian Institute of Information Technology, Design and Manufacturing, Kancheepuram Chennai 600127, India
| | - SREEKUMAR MUTHUSWAMY
- Department of Mechanical Engineering, Indian Institute of Information Technology, Design and Manufacturing, Kancheepuram Chennai 600127, India
| |
Collapse
|
6
|
Gomes IV, Puga H, Alves JL. Influence of the Adopted Balloon Modeling Strategies in the Stent Deployment Procedure: An In-Silico Analysis. Cardiovasc Eng Technol 2020; 11:469-480. [PMID: 32557187 DOI: 10.1007/s13239-020-00470-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/08/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE As the promoter of the stent expansion, the balloon plays a very important role, offering a strong influence on the deployment process. Balloon-artery interaction is pointed as a probable cause of restenosis, stressing the relevance of balloon modeling when simulating the stenting procedure. In this work, an in-silico study of the balloon modeling strategies is performed. METHODS Ultrasonic-microcasting is a novel technology that allows obtaining stents manufactured in magnesium alloys, being suggested as a promising solution. However, this technique demands superior stent strut thickness, which may have an impact on the stent deployment procedure. The influence of the balloon modeling is studied through the simulation of different balloon geometries (open- or taper-ended) and material constitutive model (linear elastic or hyperelastic) on the expanded configuration of a stent manufactured through ultrasonic-microcasting. RESULTS The results obtained suggest that the choice of balloon type has small impact in terms of demanded pressure to inflate the balloon and in the stent final radius achieved at fully-expanded configuration. Additionally, it was proved that the balloon-type influences the stent expanded profile along its length and diameter as a result of the different deformation behavior exhibited by the balloon. CONCLUSION The hyperelastic taper-ended balloon suggests being the model that better correlates with both experimental and clinical results regarding the expanded balloon profile during the procedure.
Collapse
Affiliation(s)
- I V Gomes
- CMEMS - UMinho, Guimarães, Portugal.,MIT Portugal, Guimarães, Portugal.,Department of Mechanical Engineering, University of Minho, Campus of Azurém, 4800-058, Guimarães, Portugal
| | - H Puga
- CMEMS - UMinho, Guimarães, Portugal. .,Department of Mechanical Engineering, University of Minho, Campus of Azurém, 4800-058, Guimarães, Portugal.
| | - J L Alves
- CMEMS - UMinho, Guimarães, Portugal.,Department of Mechanical Engineering, University of Minho, Campus of Azurém, 4800-058, Guimarães, Portugal
| |
Collapse
|
7
|
Lee W, Cho SW, Allahwala UK, Bhindi R. Numerical study to identify the effect of fluid presence on the mechanical behavior of the stents during coronary stent expansion. Comput Methods Biomech Biomed Engin 2020; 23:744-754. [PMID: 32427003 DOI: 10.1080/10255842.2020.1763967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In this study, structural analysis and one-way fluid-structure interaction (FSI) analysis were performed to identify the effect of fluid presence on the mechanical behavior of the stents during stent expansion. An idealized vessel model with stenosis was used for simulation, and stents made of metal and polymer were assumed, respectively. The bilinear model was applied to the stents, and the Mooney-Rivlin model was applied to the arterial wall and plaque. The blood used in the FSI analysis was assumed to be a non-Newtonian fluid. As a result of all numerical simulations, the von Mises stress, the first principal stress and the displacement were calculated as the mechanical behaviors. Through the comparison of the results of the structural analysis with those of the one-way FSI analysis, our results indicated the fluid had no significant influence on the expansion of the metal stent. However, it was found that the expansion of the polymer stent affected by the presence of fluid. These findings meant the one-way FSI technique was suggested to achieve an accurate analysis when targeting a polymer stent for numerical simulation.
Collapse
Affiliation(s)
- Wookjin Lee
- Department of Cardiology, Kolling Institute of Medical Research, Northern Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Seong Wook Cho
- School of Mechanical Engineering, Chung-Ang University, Seoul, South Korea
| | - Usaid K Allahwala
- Department of Cardiology, Royal North Shore Hospital, University of Sydney, Sydney, NSW, Australia
| | - Ravinay Bhindi
- Department of Cardiology, Royal North Shore Hospital, University of Sydney, Sydney, NSW, Australia
| |
Collapse
|
8
|
Bahreinizad H, Salimi Bani M, Khosravi A, Karimi A. A numerical study on the application of the functionally graded bioabsorbable materials in the stent design. Artery Res 2018. [DOI: 10.1016/j.artres.2018.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
|
9
|
Khosravi A, Akbari A, Bahreinizad H, Salimi Bani M, Karimi A. Optimizing through computational modeling to reduce dogboning of functionally graded coronary stent material. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2017; 28:142. [PMID: 28819891 DOI: 10.1007/s10856-017-5959-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 08/03/2017] [Indexed: 06/07/2023]
Abstract
Coronary artery disease is the leading cause of death among the men and women. One of the most suitable treatments for this problem is balloon angioplasty with stenting. Functionally graded material (FGM) stents have shown suitable mechanical behavior in simulations. While their deformation was superior to uniform materials, the study was aimed at finding the most suitable configuration to reach the optimum performance. A combination of finite element method (FEM) and optimization algorithm have been used to fulfil this objective. To do that, three different conditions have been investigated in a Palmaz-Schatz geometry, where in the first and second ones the stent was a combination of steel and CoCr alloy (L605), and the third condition was a combination of CoCr alloy (L605) and CoCr alloy (F562). In the first and third conditions, dogboning was the objective function, but in the second condition a non-uniform deformation indicator was chosen as the objective function. In all three conditions the heterogeneous index was the control variable. The stent in the third condition showed a poor performance. While in the steel/CoCr alloy (L605) stents the heterogeneous index of 0.374 showed the lowest maximum dogboning, the heterogeneous index of 5 had more uniform deformation. Overall due to the lower dogboning of the steel/CoCr alloy (L605) stent with heterogeneous index of 0.374, this stent is recommended as the optimum stent in this geometrical configuration.
Collapse
Affiliation(s)
- Arezoo Khosravi
- Atherosclerosis Research Center, Baqiyatallah University of Medical science, Tehran, Iran
| | - Amir Akbari
- Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Hossein Bahreinizad
- Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran
| | - Milad Salimi Bani
- Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
| | - Alireza Karimi
- Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| |
Collapse
|