血管及其支架内两相血流动力学研究

发布时间：2018-01-15 13:38

本文关键词：血管及其支架内两相血流动力学研究　出处：《南昌大学》2016年硕士论文　论文类型：学位论文

【摘要】：据统计,目前全国心血管病患者有2.9亿人,全国平均每5个成人中有1人患心血管病,且患病率处于持续上升的趋势。在心血管疾病致残致死的病例中,75%以上是由动脉粥样斑块造成血管狭窄病变引起的,动脉中狭窄处粥样斑块对动脉中血液流动具有一定的阻碍作用,随着狭窄程度的加大,最终造成血管堵塞并诱发心血管疾病。目前,血管支架植入术是治疗血管狭窄病变的主要手段之一,但支架植入后,支架内再狭窄问题普遍存在。而血流动力学特性参数分布与血管及其支架内动脉粥样斑块和血栓的形成具有密切的关系,对血管及其支架内的血流动力学研究有利于探明粥样斑块形成、发展和支架内再狭窄机制,为心血管疾病的诊断、治疗和血管支架的设计提供理论依据。本文针对粥样斑块引起的血管狭窄和支架内再狭窄的问题,以人体左冠状动脉为研究对象,建立了不同狭窄率的左冠状动脉几何模型和不同结构的血管支架模型,在血液与血管壁、粥样斑块和血管支架之间的流固耦合作用下,考虑血液组分的影响,将血液视为两相流体,采用计算流体力学方法对左冠状动脉和血管支架内两相血流动力学进行数值模拟,分析了狭窄率和支架结构对动脉中两相血流动力学的影响。此外,通过体外血流动力学实验对本文中数值计算方法的正确性进行了验证。本文主要研究工作和成果如下:1、运用Pro/E建立了左冠状动脉几何模型,分析了左冠状动脉内牛顿血液模型和两相血液模型的血流动力学特性参数的分布情况,获得了两相血液中红细胞的流动特性对动脉内血流动力学特性的影响,为动脉内血流动力学的研究提供了研究方法和技术条件。2、建立了不同狭窄率的左冠状动脉模型,分析了狭窄率对左冠状动脉内两相血流动力学的影响,从血流动力学角度探明了血管狭窄病变的发展过程,揭示了动脉内动脉粥样斑块形成与发展机制,对了解血管狭窄的发病机制及临床诊断与治疗均具有重要意义。3、建立了支架植入后的左冠状动脉模型和不同结构的血管支架模型,分析了支架植入对狭窄血管内血流动力学特性的影响,研究了支架结构对支架内两相血流动力学特性参数的影响,探明了支架内再狭窄机制,为血管支架的结构设计和心血管疾病的支架植入治疗提供一定的理论指导。4、对左冠状动脉模型进行体外血流动力学实验,将实验结果与数值模拟结果进行对比分析,结果表明,在动脉分叉处外侧出现一定程度的血流停滞区,血流速度较低,血流中粒子形成沉积,与数值模拟的血流动力学特性一致,验证了文中数值计算方法的正确性。
[Abstract]:According to statistics, at present, there are 290 million patients with cardiovascular disease in China, one in five adults in the country has cardiovascular disease, and the prevalence rate is on the rise. More than 75% is caused by atherosclerotic plaque. Atherosclerotic plaque in the artery has a certain blocking effect on blood flow in artery, with the increase of stenosis degree. At present, stent implantation is one of the main methods for the treatment of vascular stenosis, but after stent implantation. Restenosis in stent is a common problem, and the distribution of hemodynamic parameters is closely related to the atherosclerotic plaque and thrombosis in the blood vessel and its stent. The study of the hemodynamics of blood vessels and their stents is helpful to investigate the mechanism of atherosclerotic plaque formation, development and restenosis in stent, which is helpful for the diagnosis of cardiovascular disease. Treatment and stent design provide theoretical basis. In this paper, the human left coronary artery is taken as the research object, aiming at the problem of stenosis and restenosis caused by atherosclerotic plaque. The geometric models of left coronary artery with different stenosis rates and the stent models with different structures were established. The effects of blood components were considered under the fluid-solid coupling between blood and vascular wall, atherosclerotic plaques and stents. The blood was regarded as a two-phase fluid, and the two-phase hemodynamics in the left coronary artery and the stent was simulated numerically by computational fluid dynamics (CFD). The effects of stenosis rate and stent structure on the two-phase hemodynamics in the artery were analyzed. The validity of the numerical method in this paper is verified by the experiments of external hemodynamics. The main work and results of this paper are as follows: 1. The geometric model of left coronary artery is established by using Pro/E. The distribution of hemodynamic parameters of Newtonian blood model and two-phase blood model in left coronary artery were analyzed, and the effects of erythrocyte flow characteristics in two-phase blood on intra-arterial hemodynamic characteristics were obtained. For the study of intraarterial hemodynamics, the method and technical conditions were provided. 2. The left coronary artery model with different stenosis rates was established, and the effect of stenosis rate on the two-phase hemodynamics of left coronary artery was analyzed. From the perspective of hemodynamics, the development process of vascular stenosis was investigated, and the mechanism of atherosclerotic plaque formation and development was revealed. It is of great significance to understand the pathogenesis, clinical diagnosis and treatment of vascular stenosis. The left coronary artery model and the vascular stent model with different structures were established after stent implantation. The effects of stent implantation on the hemodynamic characteristics of stenosis were analyzed. The effects of stent structure on two-phase hemodynamic parameters in stent were studied and the mechanism of in-stent restenosis was investigated. It provides some theoretical guidance for the structural design of vascular stents and stent implantation for cardiovascular disease. The experimental results were compared with the results of numerical simulation. The results showed that there was a certain degree of blood flow stagnation on the lateral side of the artery bifurcation, the velocity of blood flow was lower, and the particles in the blood flow were deposited. In accordance with the hemodynamic characteristics of the numerical simulation, the correctness of the numerical method in this paper is verified.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R54

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