Finite element evaluation of artery damage in deployment of polymeric stent with pre- and post-dilation (original) (raw)
Related papers
Modeling of Damage Evolution in a Patient-Specific Stenosed Artery upon Stent Deployment
International Journal of Applied Mechanics, 2020
Computational models provide a powerful tool for pre-clinical assessment of medical devices and early evaluation of potential risks to the patient in terms of plaque fragmentation and in-stent restenosis (ISR). Using a suitable constitutive model for arterial tissue is key for the development of a reliable computational model. Although some inelastic phenomena such as stress softening and permanent deformation likely occur due to the supra-physiological loading of arterial tissue during the stenting procedure, hyperelastic constitutive models have been employed in most of the previously developed computational models. This study presents a finite element model for stent deployment into a patient-specific stenosed artery while inelastic arterial behaviors due to supra-physiological loading of the tissue have been considered. Specifically, the maximum stress in the plaque and the arterial layers which is the main cause of plaque fracture during stent deployment and the surgically-induced injury (damage) in the arterial wall, as the main cause of ISR, are presented. The results are compared with the commonly-used hyperelastic behavior for arterial layers. Furthermore, the effects of arterial material parameter variation, analogues to different patients, are investigated. A higher amount of damage is predicted for the artery which shows a higher stress in a specific strain.
Computational modeling of balloon-expandable stent deployment in coronary artery using the finite element method, 2019
Introduction and purpose: For the implantation of a small mechanical supporting device such as a stent, angioplasty is a more reliable technique to regain the perfusion along the heart vessel. This research work demonstrates a relative study for two different stent models during implantation in coronary artery. The purpose of this analysis was to explore the clinical efficiency of a balloon expandable stent deployment employing the finite element method. Methods: The two different models included are the Cypher Bx Velocity ® (Bx_Velocity; Johnson & Johnson Corporation, New Brunswick, NJ, USA) and Savior (ST Flex Pro; National Engineering and Scientific Commission, Islambad, Pakistan). As the majority of stents are deployed using an angioplasty balloon guided by a catheter-shaft, in this study, the delivery of stents was governed by a sophisticated balloon of a trifolded pattern, attached to the catheter-shaft. This configuration has often been neglected in the past due to the complexity of interaction and the limitation of computational power. Results: The use of a trifolded semi-compliant balloon gives more promising results for quantification with experimental data available from the manufacturer's compliance charts. This type of relative study allows us not only to improve the design of the available stent model, but also helps in probing the integrity of newly suggested models and reduces certain risks associated with the angioplasty technique. The following factors, such as stent expansion , foreshortening, dog-boning, elastic recoil, and the distribution of equivalent stresses were used to compare and improve the clinical outcome of the available stent models. Conclusion: The validation of numerical study for the Bx_Velocity stent was made with the manufacturer's compliance chart data and for the Savior Stent with a report of experimental work data from NESCOM. Finally, some suggestions were made for good deliverability and reliability based on the above design criteria.
Ecology and the Environment, 2012
Restenosis remains a significant problem in coronary intervention. Additionally, concerns have recently been raised that Drug Eluting Stents (DES) are linked to long term thrombosis. For carotid artery stenting, the most serious complication is ipsilateral neurologic events due to an acute embolus from fragmentation of the lesion during stent deployment. While much attention has focused on biocompatibility solutions to these problems, less attention has been given to matching stents to the inflation balloon, atherosclerotic plaque mechanical properties, and lesion shape. Results show that risk of arterial damage or plaque fractures are dependent on plaque morphology and material properties. Computational modeling results also indicate that it may be possible to use numerical simulations to estimate stress distributions in atherosclerotic lesions in vivo during and after stent deployment. This may help provide clinical indicators in stenting to reduce vascular injury and plaque rupture which can cause acute and long term postprocedural lumen loss in coronary artery stenting or stroke in carotid artery stenting. Results also indicate that while a complex model for plaque morphology is necessary to determine the stress distribution within the lesion, a more simple homogeneous plaque model will allow for reasonably accurate predictions of arterial stresses.
International Journal of Design & Nature and Ecodynamics, 2013
Restenosis remains a signifi cant problem in coronary intervention. Additionally, concerns have recently been raised that drug eluting stents (DES) are linked to long-term thrombosis. For carotid artery stenting, the most serious complication is ipsilateral neurologic events due to an acute embolus from fragmentation of the lesion during stent deployment. While much attention has focused on biocompatibility solutions to these problems, less attention has been given to matching stents to the infl ation balloon, atherosclerotic plaque mechanical properties, and lesion shape. Results show that the risk of arterial damage or plaque fractures is dependent on plaque morphology and material properties. Computational modeling results also indicate that it may be possible to use numerical simulations to estimate stress distributions in atherosclerotic lesions in vivo during and after stent deployment. This may help provide clinical indicators in stenting to reduce vascular injury and plaque rupture, which can cause acute and long-term post-procedural lumen loss in coronary artery stenting or stroke in carotid artery stenting. Results also indicate that while a complex model for plaque morphology is necessary to determine the stress distribution within the lesion, a more simple homogeneous plaque model will allow for reasonably accurate predictions of arterial stresses.
Simulation of stent deployment in a realistic human coronary artery
BioMedical Engineering OnLine, 2008
The process of restenosis after a stenting procedure is related to local biomechanical environment. Arterial wall stresses caused by the interaction of the stent with the vascular wall and possibly stress induced stent strut fracture are two important parameters. The knowledge of these parameters after stent deployment in a patient derived 3D reconstruction of a diseased coronary artery might give insights in the understanding of the process of restenosis.
Journal of Theoretical and Applied Mechanics
Stenting is one of the most important methods to treat atherosclerosis. Due to its simplicity and efficiency, the use of coronary stents in interventional procedures has rapidly increased, and different stent designs have been introduced in the market. In order to select the most appropriate stent design, it is necessary to analyze and compare the mechanical behavior of different types of stents. In this paper, the finite element method is used for analyzing the behavior of stents. The aim of this work is to investigate the expansion characteristics of a stent as it is deployed and implanted in an artery containing a plaque and propose a model as close to real conditions of stent implantation as possible. Furthermore, two commercially available stents (the Palmaz-Schatz and Multi-Link stents) are modeled and their behavior during the deployment is compared in terms of stress distribution, radial gain, outer diameter changes and dogboning. Moreover, the effect of stent design on the ...
Acta Biomaterialia, 2020
Vascular damage develops with diverging severity during and after percutaneous coronary intervention with stent placement and is the prevailing stimulus for in-stent restenosis. Previous work has failed to link mechanical data obtained in a realistic in vivo or in vitro environment with data collected during imaging processes. We investigated whether specimens of porcine right coronary arteries soften when indented with a stent strut shaped structure, and if the softening results from damage mechanisms inside the fibrillar collagen structure. To simulate the multiaxial loading scenario of a stented coronary artery, we developed the testing device 'LAESIO' that can measure differences in the stress-stretch behavior of the arterial wall before and after the indentation of a strut-like stamp. The testing protocol was optimized according to preliminary experiments, more specifically equilibrium and relaxation tests. After chemical fixation of the specimens and subsequent tissue clearing, we performed three-dimensional surface and second-harmonic generation scans on the deformed specimens. We analyzed and correlated the mechanical response with structural parameters of high-affected tissue located next to the stamp indentation and low-affected tissue beyond the injured area. The results reveal that damage mechanisms, like tissue compression as well as softening, fiber dispersion, and the lesion extent, are direction-dependent, and the severity of them is linked to the strut orientation, indentation pressure, and position. The findings highlight the need for further investigations by applying the proposed methods to human coronary arteries. Additional data and insights might help to incorporate the observed damage mechanisms into material models for finite element analyses to perform more accurate simulations of stent-implantations.
Materials science & engineering. C, Materials for biological applications, 2014
Finite-element simulations have been carried out to study the effects of material choice, drug eluting coating and cell design on the mechanical behaviour of stents during deployment inside a stenotic artery. Metallic stents made of materials with lower yield stress and weaker strain hardening tend to experience higher deformation and stronger dogboning and recoiling, but less residual stresses. Drug eluting coatings have limited effect on stent expansion, recoiling, dogboning and residual stresses. Stent expansion is mainly controlled by the radial stiffness of the stent which is closely associated with the stent design. In particular, open-cell design tends to have easier expansion and higher recoiling than closed-cell design. Dogboning is stronger for slotted tube design and open-cell sinusoidal design, but reduced significantly for designs strengthened with longitudinal connective struts. After deployment, the maximum von Mises stress appears to locate at the U-bends of stent ce...
Finite Element Analysis of Stent Deployment in a Stenotic Artery and Their Interactions
2011 5th International Conference on Bioinformatics and Biomedical Engineering, 2011
In this study, a nonlinear finite element analysis was implemented on the balloon-expandable stent deployment in stenotic artery with asymmetric plaque to investigate the stentstenotic artery interaction. Uniform pressure loading was applied onto the inner surface of stent to expand it. The result showed that the stent restores the patency of the stenotic artery lumen; however, non-uniform expansion (i.e. dogbone shape) was observed on stent, which indicates a possibility of the injury to arterial wall at the ends of stent. The stress on arterial wall induced by stent expansion is higher than blood pressureinduced stress, which may initiate the proliferation of smooth muscle cells and lead to the restenosis. The stent design was alternated by increasing the thickness of distal strut. With this improved design, the dogboning effect was alleviated dramatically and stress level on arterial wall was also decreased. This FEM work provided a better understanding of the coronary stenting and its effect on the arterial response from biomechanical view, which can facilitate new stent design.
Mechanical behavior of coronary stents investigated through the finite element method
Journal of Biomechanics, 2002
Intravascular stents are small tube-like structures expanded into stenotic arteries to restore blood flow perfusion to the downstream tissues. The stent is mounted on a balloon catheter and delivered to the site of blockage. When the balloon is inflated, the stent expands and is pressed against the inner wall of the coronary artery. After the balloon is deflated and removed, the stent remains in place, keeping the artery open. Hence, the stent expansion defines the effectiveness of the surgical procedure: it depends on the stent geometry, it includes large displacements and deformations and material non-linearity.