Smart Peripheral Stents for the Lower Extremity - Design, Manufacturing and Evaluation

下肢智能外周支架 - 设计、制造和评估

• 批准号: EP/R001650/1
• 负责人: Liguo Zhao
• 金额: $ 40.69万
• 依托单位: Loughborough University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FR001650%2F1
• 关键词: Smart; Peripheral; Stents; Lower; Extremity

Peripheral arterial disease refers to partial or total block of limb arteries due to the accumulation of fatty deposits on the vessel wall. The disease imposes a progressive damage to patients' health and wellbeing due to the restriction of blood supply to leg muscles. Typical symptoms include pain when walking and dying of leg tissue. The disease can be effectively treated by vascular stents which are essentially meshes of synthetic materials used to reopen the blocked blood vessels. However, stenting in peripheral arteries has proved problematic, given the complexity of the disease and constant exposure to severe biomechanical forces. Consequently, it requires customised design in order to improve patency times and reduce complications in interventional therapy. In addition, current stent manufacturing (such as laser cutting and photo etching) is a material wasteful and time consuming process. Additive manufacturing (AM) via Selective Laser Melting (SLM) offers the most promising approach to generate stents with customized designs and extensive saving of raw materials. This research aims to develop smart stents for treatment of complex periphery artery stenosis in the lower limbs. Superelastic shape memory alloy, Nitinol, will be used in this study, as the material is extremely flexible and can automatically recover its original shape even after very large deformation (smart nature). Stents made of Nitinol demonstrate high conformability to the complex vessel geometry in diseased regions.To achieve the aim, the Mechanics of Advanced Materials group at LU, the Advanced Materials & Processing Lab at UoB and the Bioengineering group at MMU are brought together to collaboratively work on the project. UoB will focus on adapting SLM for manufacturing structures (samples and prototypes), with smaller feature sizes (less than 200 microns), out of Nitinol powders. In particular, UoB will apply micro-doping of platinum group metals to improve the biocompatibility and radiopacity of SLMed Nitinol, as well as develop techniques to prevent Ni evaporation which occurs during SLM and can result in significant loss of superelastic behaviour. Mechanical behaviour of the samples and stents, delivered by UoB, will be tested at LU using a stent crimper and a microtester fitted with an environmental bath. Samples and stents, both as-received and tested, will undergo SEM/TEM/EBSD characterisation to gain further insights of the SLMed Nitinol behaviour. An in-vitro setup at MMU will be used to study the in-vitro performance, including haemodynamics, of stent prototypes subjected to optional biomechanical forces such as bending and radial compression. These experimental studies will provide further guidance to UoB for optimisation of key SLM parameters. In addition, a mesoscale computer model will be developed at UoB to simulate the AM process, including micro-doping and Ni evaporation, to support the adaption and optimisation of the micro-SLM process. Finite element simulations of stent deformation will be carried out jointly by LU (solid mechanics) and MMU (fluid mechanics), including in-vitro and in-silico modelling of local deformation and haemodynamics of the stent-artery system. Simulation results will be compared with experimental results. The researchers at LU will also deliver the design of lesion-specific stents to UoB for AM of customised stents. Particular considerations will be given to designs which best suits the SLM process. The design will be based on 3D lesion imaging of actual patients provided by MMU and iterative finite element analyses at LU, with in-vitro performance assessment at MMU. The outcome will serve as a driving force to boost the development of personalised therapies, especially for complex and critical diseases in vulnerable patients such as ageing populations.

周围动脉疾病是指由于血管壁上脂肪沉积物的积累，肢体动脉的部分或总动脉。由于对腿部肌肉的血液供应限制，该疾病对患者的健康和健康造成了逐渐损害。典型的症状包括行走和腿组织死亡时的疼痛。该疾病可以通过血管支架有效治疗，血管支架本质上是用于重新开放血管的合成材料的网格。然而，鉴于疾病的复杂性和持续暴露于严重的生物力学力，周围动脉支架的支架已被证明是有问题的。因此，它需要定制设计，以改善通畅时间并减少介入治疗的并发症。此外，当前的支架制造（例如激光切割和照片蚀刻）是一种浪费且耗时的过程。通过选择性激光熔化（SLM）通过选择性的增材制造（AM）提供了最有前途的方法，可以通过定制设计和广泛节省原材料来生成支架。这项研究旨在开发智能支架，以治疗下肢复杂的周围动脉狭窄。超弹性形状的内存合金NITINOL将在本研究中使用，因为该材料非常灵活，即使经过非常大的变形（智能自然），也可以自动恢复其原始形状。由硝基醇制成的支架表现出与患病区域中复杂血管几何形状的高相称性。在项目上。 UOB将专注于将SLM用于制造结构（样品和原型），具有较小的特征大小（小于200微米），含有尼替醇粉末。特别是，UOB将对铂类金属进行微掺杂，以改善SLMED NITINOL的生物相容性和放射性，并开发技术以防止SLM期间发生的Ni蒸发，并可能导致极大的弹性行为丧失。由UOB传递的样品和支架的机械行为将在LU上使用支架压接机和装有环境浴的Microtester进行测试。样品和支架都将经过验证和测试，将经历SEM/TEM/EBSD表征，以获得SLMED NININOL行为的进一步见解。在MMU上进行的体外设置将用于研究受到可选生物力学作用（例如弯曲和径向压缩）的支架原型的体外性能，包括血流动力学。这些实验研究将为UOB提供进一步的指导，以优化关键SLM参数。此外，将在UOB开发中尺度计算机模型，以模拟AM过程，包括微掺杂和NI蒸发，以支持Micro-SLM过程的适应和优化。支架变形的有限元模拟将通过LU（固体力学）和MMU（流体力学）共同进行，包括支架 - 动脉系统的局部变形和血液动力学的局部和硅内建模。模拟结果将与实验结果进行比较。 LU的研究人员还将为UOB提供定制支架的UOB的特定病变支架的设计。将对最适合SLM过程的设计进行特殊考虑。该设计将基于MMU提供的实际患者的3D病变成像和LU的迭代有限元分析，并在MMU进行了体外绩效评估。该结果将成为促进个性化疗法发展的驱动力，尤其是对于诸如衰老人群等脆弱患者的复杂和严重疾病。

项目成果

Computational Evaluation of Artery Damage in Stent Deployment

• DOI: 10.1016/j.prostr.2018.12.031
• 发表时间: 2018-01-01
• 期刊: ECF22 - LOADING AND ENVIRONMENTAL EFFECTS ON STRUCTURAL INTEGRITY
• 作者: He, Ran;Zhao, Liguo;Vogt, Felix
• 通讯作者: Vogt, Felix

Distinguish the Stable and Unstable Plaques Based on Arterial Waveform Analysis

• DOI: 10.1016/j.prostr.2019.07.002
• 发表时间: 2019
• 期刊: Procedia Structural Integrity
• 作者: M. Abdulsalam;Jiling Feng

In silico evaluation of additively manufactured 316L stainless steel stent in a patient-specific coronary artery.

• DOI: 10.1016/j.medengphy.2022.103909
• 发表时间: 2022-10
• 期刊: Medical engineering & physics
• 影响因子: 2.2
• 作者: R. He;E. Langi;Rebecca Garrard;Moataz M. Attallah;V. Silberschmidt;F. Vogt;Liguo Zhao

Mechanistic evaluation of long-term in-stent restenosis based on models of tissue damage and growth.

• DOI: 10.1007/s10237-019-01279-2
• 发表时间: 2020-10
• 期刊: Biomechanics and modeling in mechanobiology
• 影响因子: 3.5
• 作者: He R;Zhao L;Silberschmidt VV;Liu Y
• 通讯作者: Liu Y

Effect of balloon pre-dilation on performance of self-expandable nitinol stent in femoropopliteal artery.

• DOI: 10.1007/s10237-022-01641-x
• 发表时间: 2023-02
• 期刊: BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
• 影响因子: 3.5
• 作者: He, Ran;Zhao, Liguo;Silberschmidt, Vadim V.
• 通讯作者: Silberschmidt, Vadim V.