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A Computational Framework Examining the Mechanical Behaviour of Bare and Polymer-Covered Self-Expanding Laser-Cut Stents. Cardiovasc Eng Technol 2021; 13:466-480. [PMID: 34850370 DOI: 10.1007/s13239-021-00597-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 11/16/2021] [Indexed: 01/22/2023]
Abstract
PURPOSE Polymer covered stents have demonstrated promising clinical outcomes with improved patency rates compared to traditional bare-metal stents. However, little is known on the mechanical implication of stent covering. This study aims to provide insight into the role of a polymeric cover on the biomechanical performance of self-expanding laser-cut stents through a combined experimental-computational approach. METHODS Experimental bench top tests were conducted on bare and covered versions of a commercial stent to evaluate the radial, axial and bending response. In parallel, a computational framework with a novel covering strategy was developed that accurately predicts stent mechanical performance. Different stent geometries and polymer materials were also considered to further improve understanding on covered stent mechanics. RESULTS Results show that stent covering causes increased initial axial stiffness and up to 60% greater radial resistive force at small crimp diameters as the cover folds and self-contacts. The incorporation of a cover allows stent designs without interconnecting struts, thereby providing improved flexibility without compromising radial force. It was also shown that use of a stiffer PET polymeric covering material caused significant alterations to the radial and axial response, with the initial axial stiffness increasing six-fold and the maximum radial resistive force increasing four-fold compared to a PTFE-PU covered stent. CONCLUSION This study demonstrates that stent covering has a substantial effect on the overall stent mechanical performance and highlights the importance of considering the mechanical properties of the combined cover and stent.
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Liu J, Meng J, Zhou C, Shi Q, Yang C, Ma J, Chen M, Xiong B. A new choice of stent for transjugular intrahepatic portosystemic shunt creation: Viabahn ePTFE covered stent/bare metal stent combination. J Interv Med 2021; 4:32-38. [PMID: 34805945 PMCID: PMC8562232 DOI: 10.1016/j.jimed.2020.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/29/2020] [Accepted: 10/10/2020] [Indexed: 12/22/2022] Open
Abstract
Objectives To compare the clinical outcomes in terms of structure and function between the insertion of a transjugular intrahepatic portosystemic shunt (TIPS) created with the Viabahn ePTFE covered stent/bare metal stent (BMS) combination and the Fluency ePTFE covered stent/BMS combination. Methods A total of 101 consecutive patients who received a TIPS from February 2016 to August 2018 in our center were retrospectively analyzed. Sixty-four subjects were enrolled in the Viabahn group and 37 were enrolled in the Fluency group. The geometry characteristics of the TIPS were calculated, and the associated occurrence of shunt dysfunction, survival, overt hepatic encephalopathy, and variceal rebleeding were evaluated. Results The technical success rate was 100%. After the insertion of the TIPS, the rate of shunt dysfunction during the first 3 months was significantly different between the Viabahn and Fluency groups (1.6% and 13.5%, respectively; p = 0.024). Multivariate analysis indicated that the angle of portal venous inflow (α) was the only independent risk factor for shunt dysfunction (hazard ratio = 1.060, 95% confidence interval = 1.009–1.112, p = 0.020). In addition, 3 months after the TIPS insertion, the α angle distinctly increased from 20.9° ± 14.3°–26.9° ± 20.1° (p = 0.005) in the Fluency group but did not change significantly in the Viabahn group (from 21.9° ± 15.1°–22.9° ± 17.6°, p = 0.798). Conclusions Shunt dysfunction was related to the α angle owing to the slight effect on the α angle after the implantation of the TIPS. The Viabahn ePTFE covered stent/BMS combination was more stable in structure and promised higher short-term stent patency compared with the Fluency ePTFE covered stent/BMS combination.
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Affiliation(s)
- Jiacheng Liu
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Jie Meng
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Chen Zhou
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Qin Shi
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Chongtu Yang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Jinqiang Ma
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Manman Chen
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
| | - Bin Xiong
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
- Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, China
- Corresponding author. Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Tidwell K, Harriet S, Barot V, Bauer A, Vaughan MB, Hossan MR. Design and Analysis of a Biodegradable Polycaprolactone Flow Diverting Stent for Brain Aneurysms. Bioengineering (Basel) 2021; 8:bioengineering8110183. [PMID: 34821749 PMCID: PMC8614946 DOI: 10.3390/bioengineering8110183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/31/2021] [Accepted: 11/09/2021] [Indexed: 11/21/2022] Open
Abstract
The flow diverting stent (FDS) has become a promising endovascular device for the treatment of aneurysms. This research presents a novel biodegradable and non-braided Polycaprolactone (PCL) FDS. The PCL FDS was designed and developed using an in-house fabrication unit and coated on two ends with BaSO4 for angiographic visibility. The mechanical flexibility and quality of FDS surfaces were examined with the UniVert testing machine, scanning electron microscope (SEM), and 3D profilometer. Human umbilical vein endothelial cell (HUVEC) adhesion, proliferation, and cell morphology studies on PCL FDS were performed. The cytotoxicity and NO production by HUVECs with PCL FDS were also conducted. The longitudinal tensile, radial, and bending flexibility were found to be 1.20 ± 0.19 N/mm, 0.56 ± 0.11 N/mm, and 0.34 ± 0.03 N/mm, respectively. The FDS was returned to the original shape and diameter after repeated compression and bending without compromising mechanical integrity. Results also showed that the proliferation and adhesion of HUVECs on the FDS surface increased over time compared to control without FDS. Lactate dehydrogenase (LDH) release and NO production showed that PCL FDS were non-toxic and satisfactory. Cell morphology studies showed that HUVECs were elongated to cover the FD surface and developed an endothelial monolayer. This study is a step forward toward the development and clinical use of biodegradable flow diverting stents for endovascular treatment of the aneurysm.
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Affiliation(s)
- Kaitlyn Tidwell
- Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034, USA; (K.T.); (S.H.); (V.B.)
| | - Seth Harriet
- Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034, USA; (K.T.); (S.H.); (V.B.)
| | - Vishal Barot
- Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034, USA; (K.T.); (S.H.); (V.B.)
| | - Andrew Bauer
- Department of Neurosurgery, University of Oklahoma-Health Science Center, Oklahoma City, OK 73104, USA;
| | - Melville B. Vaughan
- Department of Biology, University of Central Oklahoma, Edmond, OK 73034, USA;
- Center of Interdisciplinary Biomedical Education and Research, University of Central Oklahoma, Edmond, OK 73034, USA
| | - Mohammad R. Hossan
- Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034, USA; (K.T.); (S.H.); (V.B.)
- Center of Interdisciplinary Biomedical Education and Research, University of Central Oklahoma, Edmond, OK 73034, USA
- Correspondence: ; Tel.: +1-405-975-5295
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A Parametric Tool for Studying a New Tracheobronchial Silicone Stent Prototype: Toward a Customized 3D Printable Prosthesis. MATHEMATICS 2021. [DOI: 10.3390/math9172118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The management of complex airway disorders is challenging, as the airway stent placement usually results in several complications. Tissue reaction to the foreign body, poor mechanical properties and inadequate fit of the stent in the airway are some of the reported problems. For this reason, the design of customized biomedical devices to improve the accuracy of the clinical results has recently gained interest. The aim of the present study is to introduce a parametric tool for the design of a new tracheo-bronchial stent that could be capable of improving some of the performances of the commercial devices. The proposed methodology is based on the computer aided design software and on the finite element modeling. The computational results are validated by a parallel experimental work that includes the production of selected stent configurations using the 3D printing technology and their compressive test.
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McKenna CG, Vaughan TJ. A finite element investigation on design parameters of bare and polymer-covered self-expanding wire braided stents. J Mech Behav Biomed Mater 2021; 115:104305. [PMID: 33454463 DOI: 10.1016/j.jmbbm.2020.104305] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/02/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023]
Abstract
Self-expanding covered braided stents are routinely used across a diverse range of clinical applications, but few computational studies have attempted to replicate their complex behaviour. In this study, a computational framework was developed to predict the functional performance of bare and covered self-expanding wire braided stents, with a systematic evaluation on the effect of various braid and cover parameters presented. Simulated radial force and kink deformation tests show good agreement to experimental data for covered braided stents across a range of braid angles and cover thicknesses. Our results demonstrate that braid angle is a key governing parameter that dictates the radial and kink performance of both bare-metal and covered wire braided stents. It was also demonstrated that addition of a polymeric cover to a wire braided stent causes a stiffer radial response across all braid angles, particularly when thicker and/or stiffer covering systems were considered. This study represents the first experimentally-validated computational model for covered wire braided stent systems and has excellent potential to be used in future design of these devices for a range of applications.
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Affiliation(s)
- Ciara G McKenna
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
| | - Ted J Vaughan
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland.
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Jayendiran R, Nour B, Ruimi A. Computational analysis of Nitinol stent-graft for endovascular aortic repair (EVAR) of abdominal aortic aneurysm (AAA): Crimping, sealing and fluid-structure interaction (FSI). Int J Cardiol 2020; 304:164-171. [PMID: 31791620 DOI: 10.1016/j.ijcard.2019.11.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/20/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVES We evaluate the crimping strain, sealing stress and contact forces on a Nitinol stent deployed in the aorta during endovascular aortic (or aneurysm) repair (EVAR) procedures. Nitinol shape memory effect (SME) is used. We also study the fluid-structure interaction (FSI) of the blood flow on the stented aorta. METHODS We employ Solidworks to generate a closed-cell honeycomb stent structure used to treat abdominal aortic aneurysm (AAA). We use the commercial Abaqus/Simulia finite element (FEM) simulation package to study the displacements and stresses experienced by the stent during the crimping phase and deployment into the aortic segment. The Nitinol stent is covered with Dacron, a popular graft material. We implement our own user-material (UMAT) subroutines to model the shape memory effect (SME) of Nitinol. The effect of the stent geometry is analyzed. We use the FSI analysis in Abaqus/Simulia to understand the effect of hemodynamic loading on the stent. RESULTS Results indicate that the crimping strain increases as the stent strut spacing increases. This is also the case for the radius of curvature. Maximum strains developed on the stent during crimping are in the order of 10%. Stresses exerted by the stent needed to completely seal the aorta are found to be below the yield stress values of Nitinol (700 MPa). Wall shear stresses (WSS) on the stented aorta are close to WSS obtained on the aorta alone. CONCLUSION Using Nitinol's thermo-reactivity property as opposed to its superelasticity causes the stent-graft to deploy more gently.
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Affiliation(s)
- Raja Jayendiran
- Mechanical Engineering Program, Texas A&M University at Qatar, Doha, Qatar.
| | - Bakr Nour
- Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Annie Ruimi
- Mechanical Engineering Program, Texas A&M University at Qatar, Doha, Qatar.
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7
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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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Kelly N, McGrath DJ, Sweeney CA, Kurtenbach K, Grogan JA, Jockenhoevel S, O’Brien BJ, Bruzzi M, McHugh PE. Comparison of computational modelling techniques for braided stent analysis. Comput Methods Biomech Biomed Engin 2019; 22:1334-1344. [DOI: 10.1080/10255842.2019.1663414] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Nicola Kelly
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Donnacha J. McGrath
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Caoimhe A. Sweeney
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Kathrin Kurtenbach
- Institute for Textile Engineering, RWTH Aachen University, Aachen, Germany
| | - James A. Grogan
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Stefan Jockenhoevel
- Department of Biohybrid and Medical Textiles (BioTex), AME – Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Barry J. O’Brien
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Mark Bruzzi
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Peter E. McHugh
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
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9
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Thiebes AL, McGrath DJ, Kelly N, Sweeney CA, Kurtenbach K, Gesché VN, Clauser J, O'Brien B, Bruzzi M, McHugh PE, Jockenhoevel S, Cornelissen CG. Comparison of Covered Laser-cut and Braided Respiratory Stents: From Bench to Pre-Clinical Testing. Ann Biomed Eng 2019; 47:1738-1747. [PMID: 31044340 DOI: 10.1007/s10439-019-02278-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/23/2019] [Indexed: 11/30/2022]
Abstract
Lung cancer patients often suffer from severe airway stenosis, the symptoms of which can be relieved by the implantation of stents. Different respiratory stents are commercially available, but the impact of their mechanical performance on tissue responses is not well understood. Two novel laser-cut and hand-braided nitinol stents, partially covered with polycarbonate urethane, were bench tested and implanted in Rhön sheep for 6 weeks. Bench testing highlighted differences in mechanical behavior: the laser-cut stent showed little foreshortening when crimped to a target diameter of 7.5 mm, whereas the braided stent elongated by more than 50%. Testing also revealed that the laser-cut stent generally exerted higher radial resistive and chronic outward forces than the braided stent, but the latter produced significantly higher radial resistive forces at diameters below 9 mm. No migration was observed for either stent type in vivo. In terms of granulation, most stents exerted a low to medium tissue response with only minimal formation of granulation tissue. We have developed a mechanical and in vivo framework to compare the behavior of different stent designs in a large animal model, providing data, which may be employed to improve current stent designs and to achieve better treatment options for lung cancer patients.
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Affiliation(s)
- Anja Lena Thiebes
- Department of Biohybrid & Medical Textiles (BioTex), AME - Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Forckenbeckstr. 55, 52074, Aachen, Germany
| | - Donnacha J McGrath
- Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland
| | - Nicola Kelly
- Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland
| | - Caoimhe A Sweeney
- Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland
| | - Kathrin Kurtenbach
- Institute for Textile Engineering, RWTH Aachen University, Otto-Blumenthal-Str. 1, 52074, Aachen, Germany
| | - Valentine N Gesché
- Institute for Textile Engineering, RWTH Aachen University, Otto-Blumenthal-Str. 1, 52074, Aachen, Germany
| | - Johanna Clauser
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Barry O'Brien
- Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland
| | - Mark Bruzzi
- Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland
| | - Peter E McHugh
- Biomechanics Research Centre, Biomedical Engineering, College of Engineering and Informatics, National University of Ireland, University Road, Galway, Ireland
| | - Stefan Jockenhoevel
- Department of Biohybrid & Medical Textiles (BioTex), AME - Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Forckenbeckstr. 55, 52074, Aachen, Germany.
| | - Christian G Cornelissen
- Department of Biohybrid & Medical Textiles (BioTex), AME - Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Forckenbeckstr. 55, 52074, Aachen, Germany.,Clinic for Pneumology and Internistic Intensive Medicine (Medical Clinic V), Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
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10
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Jin Z, Chen Z, Wu K, Shen Y, Guo S. Investigation of Migration-Preventing Tracheal Stent with High Dose of 5-Fluorouracil or Paclitaxel for Local Drug Delivery. ACS APPLIED BIO MATERIALS 2018; 1:1328-1336. [PMID: 34996236 DOI: 10.1021/acsabm.8b00290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Stent migration is one of the common reasons for the failure of tracheal stent. An antitumor drug/tracheal stent combination can promptly relieve dyspnea caused by tracheal stenosis and locally treat malignant occupying lesion or tumor. To prevent stent migration for more effective treatment, we prepared a migration-preventing nitinol tracheal stent (TS) with a high dose of 5-fluorouracil or paclitaxel (5-FU/TS or PTX/TS) by stent surface coating with a bilayered film, which is composed of a drug-loaded layer containing Carbopol 974P as mucoadhesive matrix and a blank Carbopol 974P layer. The resulting stent had a similar mechanical performance with the nitinol tracheal stent itself. The bilayered film containing 30% PTX (PTX30) could keep adhesion to porcine mucosa for 221.7 ± 11.4 min in PBS at a stirring speed of 150 rpm, and the corresponding PTX30/TS was difficult to be moved in the porcine tracheal lumen with a pulling force less than 0.7 N, indicating its good migration-preventing ability. The migration-preventing ability of the 5-FU/TS or PTX/TS was related to the compositions of bilayered films. The 5-FU release from the 5-FU/TS was dominated by a relaxation mechanism, while the PTX release was mainly controlled by a diffusion mechanism. Moreover, the 5-FU permeation from the 5-FU loaded film through the porcine tracheal mucosa was determined by the 5-FU dissolution, and PTX permeation was limited by the trans-mucosa process. After the deployment of PTX30/TS, inflammatory responses were observed in the rabbit tracheas and gradually alleviated during the follow-up period.
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Affiliation(s)
- Zhu Jin
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Zhaoyang Chen
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Keqin Wu
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yuanyuan Shen
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Shengrong Guo
- School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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11
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Fluid-structure interaction (FSI) analysis of stent-graft for aortic endovascular aneurysm repair (EVAR): Material and structural considerations. J Mech Behav Biomed Mater 2018; 87:95-110. [DOI: 10.1016/j.jmbbm.2018.07.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 01/07/2023]
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12
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McGrath DJ, Thiebes AL, Cornelissen CG, O'Brien B, Jockenhoevel S, Bruzzi M, McHugh PE. Evaluating the interaction of a tracheobronchial stent in an ovine in-vivo model. Biomech Model Mechanobiol 2017; 17:499-516. [PMID: 29177931 DOI: 10.1007/s10237-017-0974-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 10/28/2017] [Indexed: 12/19/2022]
Abstract
Tracheobronchial stents are used to restore patency to stenosed airways. However, these devices are associated with many complications such as stent migration, granulation tissue formation, mucous plugging and stent strut fracture. Of these, granulation tissue formation is the complication that most frequently requires costly secondary interventions. In this study a biomechanical lung modelling framework recently developed by the authors to capture the lung in-vivo stress state under physiological loading is employed in conjunction with ovine pre-clinical stenting results and device experimental data to evaluate the effect of stent interaction on granulation tissue formation. Stenting is simulated using a validated model of a prototype covered laser-cut tracheobronchial stent in a semi-specific biomechanical lung model, and physiological loading is performed. Two computational methods are then used to predict possible granulation tissue formation: the standard method which utilises the increase in maximum principal stress change, and a newly proposed method which compares the change in contact pressure over a respiratory cycle. These computational predictions of granulation tissue formation are then compared to pre-clinical stenting observations after a 6-week implantation period. Experimental results of the pre-clinical stent implantation showed signs of granulation tissue formation both proximally and distally, with a greater proximal reaction. The standard method failed to show a correlation with the experimental results. However, the contact change method showed an apparent correlation with granulation tissue formation. These results suggest that this new method could be used as a tool to improve future device designs.
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Affiliation(s)
- Donnacha J McGrath
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland
| | - Anja Lena Thiebes
- Department of Biohybrid and Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, ITA-Institut für Textiltechnik, RWTH Aachen University and at AMIBM Maastricht University, Maastricht, The Netherlands, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Christian G Cornelissen
- Department of Biohybrid and Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, ITA-Institut für Textiltechnik, RWTH Aachen University and at AMIBM Maastricht University, Maastricht, The Netherlands, Pauwelsstr. 20, 52074, Aachen, Germany.,Department for Internal Medicine - Section for Pneumology, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Barry O'Brien
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland
| | - Stefan Jockenhoevel
- Department of Biohybrid and Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, ITA-Institut für Textiltechnik, RWTH Aachen University and at AMIBM Maastricht University, Maastricht, The Netherlands, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Mark Bruzzi
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland
| | - Peter E McHugh
- Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland.
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Puértolas S, Navallas D, Herrera A, López E, Millastre J, Ibarz E, Gabarre S, Puértolas J, Gracia L. A methodology for the customized design of colonic stents based on a parametric model. J Mech Behav Biomed Mater 2017; 71:250-261. [DOI: 10.1016/j.jmbbm.2017.03.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 02/24/2017] [Accepted: 03/25/2017] [Indexed: 12/16/2022]
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An ovine in vivo framework for tracheobronchial stent analysis. Biomech Model Mechanobiol 2017; 16:1535-1553. [DOI: 10.1007/s10237-017-0904-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 03/27/2017] [Indexed: 12/19/2022]
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15
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Chen W, Clauser J, Thiebes AL, McGrath DJ, McHugh PE, Steinseifer U, Jockenhoevel S, Hennink WE, Kok RJ. Selection and fabrication of a non-woven polycarbonate urethane cover for a tissue engineered airway stent. Int J Pharm 2016; 514:255-262. [DOI: 10.1016/j.ijpharm.2016.06.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/17/2016] [Accepted: 06/18/2016] [Indexed: 11/16/2022]
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