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Referring to mortality increasment having sprung from atherosclerosis, work on treatment of coronary heart disease seems to be necessary. Stent implementation is one of stenosis treatment. Stent deployment has been done during past two decades, but clinical evidence showed that because of some weakness in designing and implementing, restenosis occurs again. Material, structure and coating texture of stent are the designing criteria beside stent implementation importance. Thus a lot of activities have been done in this area to improve performance of these applications. Nowadays a lot of companies' researchers try the best to get better their products; consequently there is different types of... 

The coronary arteries of the heart are one of the most important arteries in the body's cardiovascular system, which carry oxygen and nutrients to the heart.Therefore, coronary heart disease is one of the most important causes of death in society. In this disease, when the adhesion of sediments and blood plugs to the walls of the arteries increase, the ducts become narrow and the circulatory system gets hard. As a result, the risk of heart attack and mortality increases.Due to the increase in mortality caused by coronary heart disease, working on treatment methods for this disease is important. Angioplasty and stent implantation in a vein are the latest treatments for this disease and have... 

Due to increased mortality from Coronary Heart Disease, it is important to work on ways to treat this disease. An effective method of treatment on this disease is the coronary stent implantation. There are nearly two decades passed since implanting the first heart stent. The main objective of this research is design and manufacturing of the medical stents of stainless steel 316 L. Stent materials should have excellent corrosion resistance and biocompatibility. Various materials such as stainless steel 316 L, platinum alloys, niobium alloys, cobalt alloys are used for manufacturing the stents. In this project, at the first stage seam tube was prodected with laser welding of a tube with... 

Cardiovascular diseases are the major cause of death worldwide. Atherosclerosis is one of the major types of cardiovascular diseases in which fibrous and fatty materials, called plaque, build up inside the artery and cause partial or total occlusion of the artery. Intravascular balloon angioplasty with or without stenting is the most common treatment of this disease. In 2010, approximately 954000 stent implantations were performed in the United States. The major issue associated with stenting is reclosure or renarrowing of the transverse section of the artery termed in-stent restenosis (ISR). Unfortunately, nearly one–third of the patients
who receive stent implantation require further... 

The present study examines the mechanical properties of auxetic stents with various types of structures. Geometries was parametrically modeled and the design of experiments (DOE) was developed by defining the elastic properties of the stents and using the response surface method (RSM). Finite element (FE) analysis was performed in order to find a polynomial relationship between the geometric parameters as inputs and the elastic parameters as the outputs. Then, the optimal stent was obtained in terms of elasticity parameters by using RSM and NSGA-II methods and the two-dimensional Pareto front was plotted. For instance, the optimal parameters of the Re-entrant stent including flexural... 

The application of computational fluid dynamics (CFD) has been growing rapidly in biomedical engineering. The altered hemodynamics inside the blood vessels plays a key role in the development of the arterial disease called atherosclerosis, which is the major cause of human death worldwide. Atherosclerosis is often treated with the stenting procedure to restore the normal blood flow. A stent is a tubular, flexible structure, usually made of metals, which is driven and expanded in the blocked arteries. The presence of non-biological device in the artery causes inflammation or re-growth of atherosclerotic lesions in the treated vessels. Several factors including the design of stents and type of... 

Magnesium and its alloys have gained much attention in medical applications, especially bio-degradable stents. However, they have not been used extensively due to their natural limitations, such as weak mechanical properties. WE43 magnesium alloy has gained attention as a bio-alloy due to its high temperature and good corrosion resistance. The present study aims to use a combination of ECAP and direct tube extrusion to fabricate thin wall tubes with good mechanical properties using WE43 magnesium alloy. In the first phase, the ECAP process at 370°C were conducted up to 4 passes on the homogenized samples to reach ultrafine grain structure. Subsequent to ECAP, direct tube extrusion at 230 °C,... 

Properties of stents are significantly dependent on the mechanical properties of the microtubes used in their construction. Therefore, investigating the influence of various factors on the mechanical behavior of magnesium microtubes employed in the fabrication of biodegradable stents can play an indispensable role in the development of the emerging industry of biodegradable stent manufacturing. In this dissertation, the effects of different parameters on the mechanical behavior of magnesium microtubes used in the construction of biodegradable stents have been examined. To achieve this, the objectives of this dissertation have been divided into three main sections. In the first section, a...