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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

基本信息

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

项目摘要

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.

外周动脉疾病是指由于脂肪沉积在血管壁上而导致肢体动脉部分或全部阻塞。由于腿部肌肉的血液供应受到限制，这种疾病对患者的健康和福祉造成了进行性损害。典型症状包括走路时疼痛和腿部组织坏死。这种疾病可以通过血管支架有效治疗，血管支架本质上是合成材料的网状物，用于重新打开堵塞的血管。然而，考虑到疾病的复杂性和持续暴露于严重的生物力学力，外周动脉支架植入术被证明是有问题的。因此，它需要定制的设计，以提高通畅时间和减少并发症的介入治疗。此外，目前的支架制造（如激光切割和光刻）是一种材料浪费和耗时的过程。通过选择性激光熔化（SLM）的增材制造（AM）提供了最有前途的方法来生产具有定制设计和广泛节省原材料的支架。本研究旨在开发用于治疗下肢复杂外周动脉狭窄的智能支架。超弹性形状记忆合金镍钛诺将用于本研究，因为该材料具有极高的柔韧性，即使在非常大的变形后也能自动恢复其原始形状（智能性质）。镍钛诺制成的支架对病变区域复杂的血管几何形状具有高度的顺应性。为了实现这一目标，卢大的先进材料力学小组、大华大学的先进材料与加工实验室和MMU的生物工程小组聚集在一起，共同开展该项目。大华银行将专注于将SLM用于镍钛诺粉末的制造结构（样品和原型），具有更小的特征尺寸（小于200微米）。特别是，UoB将应用铂族金属的微掺杂来改善SLMed镍钛诺的生物相容性和不透光性，以及开发技术来防止SLM过程中发生的Ni蒸发，这可能导致超弹性行为的显著丧失。UoB提供的样品和支架的机械性能将在LU使用支架卷曲器和配备环境浴的微测试仪进行测试。接收和测试的样品和支架将进行SEM/TEM/EBSD表征，以进一步了解SLMed镍钛诺的行为。MMU的体外装置将用于研究支架原型在可选的生物力学力（如弯曲和径向压缩）下的体外性能，包括血流动力学。这些实验研究将为UoB优化关键SLM参数提供进一步的指导。此外，大华大学将开发一个中尺度计算机模型来模拟AM过程，包括微掺杂和Ni蒸发，以支持微slm过程的适应和优化。支架变形的有限元模拟将由LU（固体力学）和MMU（流体力学）联合进行，包括支架-动脉系统局部变形和血流动力学的体外和计算机模拟。将仿真结果与实验结果进行比较。LU的研究人员还将向UoB提供病变特异性支架的设计，用于定制支架的AM。将特别考虑最适合SLM过程的设计。该设计将基于MMU提供的实际患者的三维病变成像和LU的迭代有限元分析，并在MMU进行体外性能评估。这一结果将成为推动个性化疗法发展的推动力，特别是针对老年人等弱势患者的复杂和危重疾病。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

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
影响因子：
0
作者：
M. Abdulsalam;Jiling Feng
通讯作者：
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
通讯作者：
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.