| Stent implantation is permanently implanting stent in the arterial stenosis. Stent stenosis depend on the physical properties of the support, final repair from stenosis of the lumen diameter,ensure that the blood flow rate within the stenosis.In the process of clinical therapy, stenosis plaque structure is diverse and different plaque components, which have a significant impact on the expansion effect and therapeutic effect of stent implantation.On the other hand, the structure and material of the stent scaffold supporting performance is also affected,and ultimately affect the treatment of the stent.This paper analyzes the impact of different support structure for supporting the performance of the stent,and analysis of force and deformation of the stent in the real stenosis model.The main content is divided into three parts: The first part is to use the method of finite element analysis, fatigue life analysis of three different stent strut cross-sectional and analysis of the forces and the stent.The second part using three-dimensional modeling method to construct the actual vessel model and plaque model.Finite element analysis was used to simulate the process of releasing stent in stenosis model, discuss vascular plaque, stress and deformation of the stent. Finally, according to the stent finite element analysis to design a new type of stent.Firstly, three stents with different cross-sections were built by the three-dimensional modeling software. Three cross-sectional ship are triangular, circular and rectangular. Then, mechanical analysis of these stents by the finite element analysis software were imported into fatigue analysis software to predict the fatigue life. So as to compare their fatigue life situations under the same external load. Secondly, realistic stenosis arteries were built basing on CT image of carotid artery. Different material properties were given to vessel wall and plaque. Stent release procedure in real stenosis model was simulated by finite element analysis software. Finally, the stress and deformation characteristics of the stent was investigated. A braided stent and new vascular stents considering the structural characteristics and functional properties of different stent considering the structural characteristics and functional properties of different stent. Which was to improve the support performance and supple performance. Besides, finite element analysis methods was used to verify the mechanical properties of the new stent.By the final calculated, the proportion of the number of units of which fatigue life is smaller than 107 is 0.33%, 6.45%, 53%, respectively. Fatigue life of stent with triangular cross-section is the minimum, stent with rectangular cross-section is the maximum. In the stent expansion phase, the maximum shear stress of stent, plaque and artery were 515.0MPa, 2.482 MPa and 1.053 Mpa respectively. In the contraction phase were 464.50 MPa, 0.954 MPa and 0.316 MPa respectively. In addition, by comparing the results with the original holder, there is an advantages in support performance and supple performance.The results from different section of the stent can be obtained: under the same pressure, fatigue safety of stent with rectangular cross-section was the best, triangular cross-section was worst. When the stent is expanded, plaques and vascular wall suffered the greatest damage. In the contraction phase, the stent form a "dog-bone" effect. This analysis distinct stenosis vascular tissue components to more in line with real biomechanics of stenosis. This study can provide guidance to stent design and stent interventional therapy. |
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