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.

中文翻译：

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支架展开时患者特异性狭窄动脉损伤演变的建模

计算模型为医疗器械的临床前评估和早期评估患者在斑块碎裂和支架内再狭窄 (ISR) 方面的潜在风险提供了强大的工具。为动脉组织使用合适的本构模型是开发可靠计算模型的关键。尽管在支架置入过程中由于动脉组织的超生理负荷可能会出现一些非弹性现象，例如应力软化和永久变形，但在大多数先前开发的计算模型中都采用了超弹性本构模型。本研究提出了一个有限元模型，用于将支架部署到患者特定的狭窄动脉中，同时考虑了由于组织的超生理负荷导致的非弹性动脉行为。具体来说，介绍了斑块和动脉层的最大应力是支架展开过程中斑块破裂的主要原因，以及动脉壁的手术引起的损伤（损伤）是ISR的主要原因。将结果与动脉层常用的超弹性行为进行比较。此外，还研究了动脉材料参数变化对不同患者的影响。对于在特定应变中显示出更高应力的动脉，预计会出现更高程度的损伤。此外，还研究了动脉材料参数变化对不同患者的影响。对于在特定应变中显示出更高应力的动脉，预计会出现更高程度的损伤。此外，还研究了动脉材料参数变化对不同患者的影响。对于在特定应变中显示出更高应力的动脉，预计会出现更高程度的损伤。