Patient-specific modelling of stent overlap: Lumen gain, tissue damage and in-stent restenosis (original) (raw)
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Biomechanics and Modeling in Mechanobiology, 2019
Using finite element method, this paper evaluates damage in an arterial wall and plaque caused by percutaneous coronary intervention. Hyperelastic damage models, calibrated with experimental results, are used to describe stress-stretch responses of arterial layers and plaque; these models are capable to simulate softening behaviour of the tissue due to damage. Abaqus CAE is employed to create the finite element models for the artery wall (with media and adventitia layers), a symmetric uniform plaque, a bioresorbable polymeric stent and a tri-folded expansion balloon. The effect of percutaneous coronary intervention on vessel damage is investigated by simulating the processes of vessel pre-dilation, stent deployment and poststenting dilation. Energy dissipation density is used to assess the extent of damage in the tissue. Softening of the plaque and the artery, due to the pre-dilation-induced damage, can facilitate the subsequent stent deployment process. The plaque and the artery experienced heterogeneous damage behaviour after the stent deployment, caused by non-uniform deformation. The post-stenting dilation was effective to achieve a full expansion of the stent, but caused additional damage to the artery. The continuous and discontinuous damage models yielded similar results in the percutaneous coronary intervention simulations, while the incorporation of plaque rupture affected the simulated outcomes of stent deployment. The computational evaluation of the artery damage can be potentially used to assess the risk of in-stent restenosis after percutaneous coronary intervention.
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 ...
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.
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.
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.
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.
Medical & Biological Engineering & Computing, 2009
Many clinical studies, including the ISAR-STEREO trial, have identified stent strut thickness as an independent predictor of in-stent restenosis where thinner struts result in lower restenosis than thicker struts. The aim of this study was to more conclusively identify the mechanical stimulus for in-stent restenosis using results from such clinical trials as the ISAR-STEREO trial. The mechanical environment in arteries stented with thin and thicker strut stents was investigated using numerical modelling techniques. Finite element models of the stents used in the ISAR-STEREO clinical trial were developed and the stents were deployed in idealised stenosed vessel geometries in order to compare the mechanical environment of the vessel for each stent. The stresses induced within the stented vessels by these stents were compared to determine the level of vascular injury caused to the artery by the stents with different strut thickness. The study found that when both stents were expanded to achieve the same initial maximum stent diameter that the thinner strut stent recoiled to a greater extent resulting in lower luminal gain but also lower stresses in the vessel wall, which is hypothesised to be responsible for the lower restenosis outcome. This study supports the hypothesis that arteries develop restenosis in response to injury, where high vessel stresses are a good measure of that injury. This study points to a critical stress level in arteries, above which an aggressive healing response leads to in-stent restenosis in stented vessels. Stents can be designed to reduce stresses in this range in arteries using preclinical tools such as numerical modelling.
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.
The aim of this work is to introduce a methodology to study the stent expansion and the subsequent deformation of the arterial wall towards the outside direction in order arterial lesion to be rehabilitated and blood flow to be restored. More specifically, a coronary artery and the plaque are reconstructed using intravascular ultrasound and biplane angiography. The finite element method is used for the modeling of the interaction between the stent, balloon, arterial wall and plaque. Appropriate material properties and boundary conditions are applied in order to represent the realistic behavior of each component. We observe that stresses are increased at the region of the first contact between the stent and the wall, which may be considered crucial for plaque rupture. Furthermore, the average calculated stress on the plaque is higher than the average stress on the arterial wall. Thus, stent positioning and deployment depends on a considerable degree on the plaque properties rather than the general arterial geometry. Results indicate that numerical modeling can provide a prediction of the arterial behavior during stent implantation.
13th IEEE International Conference on BioInformatics and BioEngineering, 2013
S tents are medical devices used in cardiovascular intervention for unblocking the diseased arteries and restoring blood flow. During stent implantation the deformation of the arterial wall as well as the resulted stresses caused in the arterial morphology are studied. In this paper we study the effect of the composition of the atherosclerotic plaque during the stent deployment procedure, using Finite Element modeling. The stenting procedure is simulated for two different cases; in the first the presence of the plaque is ignored whereas in the second a three dimensional (3D) stiff calcified plaque is located in the stenotic area of the artery. Results indicate that in the second case the von Mises stresses in the arterial wall are higher than the stresses occurred in the first case. In addition, the distribution of the arterial von Mises stress depends on the plaque composition.