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Biomedical Engineering and Bioengineering Commons™
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Articles 1 - 12 of 12
Full-Text Articles in Biomedical Engineering and Bioengineering
Modified Stent Design For A Coronary Bifurcation Lesion, Abigail Nowell
Modified Stent Design For A Coronary Bifurcation Lesion, Abigail Nowell
Biological Sciences Undergraduate Honors Theses
Currently, 18.2 million adults aged 20 and older are diagnosed with Coronary Artery Disease (CAD) (Benjamin et al., 2019). Stenosis is the most common intervention. However, when a patient has a bifurcated artery, treatment becomes more difficult and is often unsuccessful. This project created a new stent and balloon complex that was tested in vitro using a gel phantom artery model. Two separate prototypes have been created and tested so far, with improvements made upon each. Testing is still underway with Prototype 2.
Degradable Zinc Material Characteristics And Its Influence On Biocompatibility In An In-Vivo Murine Model, Roger J. Guillory Ii
Degradable Zinc Material Characteristics And Its Influence On Biocompatibility In An In-Vivo Murine Model, Roger J. Guillory Ii
Dissertations, Master's Theses and Master's Reports
Biodegradable stents based on zinc have been under development since their introduction in 2013. While metallic zinc is highly ductile, it unfortunately lacks the mechanical strength required for arterial stents. This has led to the development of an abundance of novel zinc-based materials, with the aim of improving the mechanical strength without sacrificing too much ductility. Although these materials are intended to function and slowly degrade within an artery, most zinc-based materials have been developed without deep consideration for their biological effects.
The present work explores the biological effects elicited by zinc-based materials implanted within the arterial system. The biological …
Evaluating Wall Shear Stress Indices To Uncover Stimuli For Restenosis And Malapposition In Stented Coronary Arteries, Ali A. Aleiou
Evaluating Wall Shear Stress Indices To Uncover Stimuli For Restenosis And Malapposition In Stented Coronary Arteries, Ali A. Aleiou
Master's Theses (2009 -)
The cause of coronary artery neointimal thickening leading to restenosis in ~10% of drug-eluting stents is unknown. Although research suggests adverse values of traditional wall shear stress (WSS) indices may contribute, studies to date have not accounted for stent geometry, which dictates local WSS patterns influencing drug concentration. Recently proposed WSS indices such as WSS variability and WSS exposure time (WSSET) may shed further light on restenosis or, the opposite effect, resorption. The objective of this investigation was to locally evaluate traditional and recently proposed post-stenting metrics and their respective impact on restenosis or resorption. This study used de-identified data …
Renal Artery Stent Fatigue Test, Braden Cooper, Munir Eltal, Jennifer Hawthorne, Ashley Schaefer
Renal Artery Stent Fatigue Test, Braden Cooper, Munir Eltal, Jennifer Hawthorne, Ashley Schaefer
Mechanical Engineering
In today’s world of medical innovation, regulations and requirements set by organizations such as the Food and Drug Administration (FDA), the International Organization for Standardization (ISO), and ASTM International (American Society for Testing and Materials) can inhibit rapid innovation by demanding rigorous testing of new designs. For arterial stents, the standard is that each design must be tested to simulate 10 years of life in an environment congruent to an in vivo environment. Endologix in Irvine, California develops and manufactures minimally invasive treatments for aortic diseases, with a focus on stent grafts for the treatment of abdominal aortic aneurysms (AAA). …
Engineering The “Pluripotency” Of Zr-Based Bulk Metallic Glasses As Biomedical Materials, Lu Huang
Engineering The “Pluripotency” Of Zr-Based Bulk Metallic Glasses As Biomedical Materials, Lu Huang
Doctoral Dissertations
Bulk metallic glasses (BMGs) are a family of novel alloys with amorphous microstructures. The combination of their excellent mechanical properties, good chemical stability, high thermal formability, and general biocompatibility has brought up new opportunities for biomaterials. Research in this dissertation was focused on exploring multiple biomedical functionalities of Zr-based BMGs over a wide spectrum, combining materials and biological characterizations, through experimental and computational approaches. Four distinct yet interconnected tasks were endeavored, involving inflammation, hard-tissue implant, soft-tissue prosthesis, and pathogenic infection.
The inflammation that can be potentially triggered by Zr-based BMGs was investigated using macrophages. Lower level or comparable macrophage activations …
Biocorrosion Rate And Mechanism Of Metallic Magnesium In Model Arterial Environments, Patrick Bowen
Biocorrosion Rate And Mechanism Of Metallic Magnesium In Model Arterial Environments, Patrick Bowen
Dissertations, Master's Theses and Master's Reports
A new paradigm in biomedical engineering calls for biologically active implants that are absorbed by the body over time. One popular application for this concept is in the engineering of endovascular stents that are delivered concurrently with balloon angioplasty. These devices enable the injured vessels to remain patent during healing, but are not needed for more than a few months after the procedure. Early studies of iron- and magnesium-based stents have concluded that magnesium is a potentially suitable base material for such a device; alloys can achieve acceptable mechanical properties and do not seem to harm the artery during degradation. …
Continuum Deformation Model For Drug-Eluting Stent (Des) Medical Devices Using Finite Element Analysis (Fea), Solki Lee
Theses and Dissertations
The development of coronary stent medical devices was originally considered as a major advance in the treatment of obstructive cardiovascular disease. The implantation of stent, however, involves clinical adverse effects such as re-narrowing of arterial wall after stenting. Drug-eluting stents (DES) have been developed to prevent such adverse effects by slowly delivering anti-proliferative and/or anti-inflammatory drugs from coating composites of drug-containing polymers. One of the major issues in DES implantation is, however, that the coatings comprised of drug and polymer composite phases are often fractured or delaminated during the deployment of stent, which can lead to more serious clinical complications. …
Evaluation Of Corrosion Properties Of Proprietary Metal Alloy Stents For In-Vivo Use, Michael David Bremner
Evaluation Of Corrosion Properties Of Proprietary Metal Alloy Stents For In-Vivo Use, Michael David Bremner
Materials Engineering
To assess corrosion rates of metal alloy bio-absorbable stents an experimental set-up was designed to mimic the coronary artery environment. The artery was modeled using 4mm diameter Tecoflex tubing and the metal alloy stents were inserted into the tubing using a catheter. As is the case in cardiac surgery, the catheter with the stent and a microballoon were maneuvered to the desired position. The microballoon was then slowly inflated to expand the stent and compress it against the tubing walls. The catheter and microballoon were then withdrawn. A circulating pump system was set up to cycle fetal bovine serum (FBS) …
Evaluation Of Corrosion Properties For Use Of Az31b In Bioabsorbable Stents And In Vivo Corrosion Rate Prediction Using Fea, Jared Vidales, Austin Schader, Jenna Jerman, Michael Turovskiy
Evaluation Of Corrosion Properties For Use Of Az31b In Bioabsorbable Stents And In Vivo Corrosion Rate Prediction Using Fea, Jared Vidales, Austin Schader, Jenna Jerman, Michael Turovskiy
Materials Engineering
AZ31B was heat treated to evoke more controlled and uniform corrosion. 1/16” diameter AZ31B wire was cut into six samples each 1” long. The samples underwent heat treatments following ASTM B661-06. Samples were weighed and placed into three different in vitro environments. In the first scenario two samples of each heat treatment were individually placed in 50 ml of saline solution at 0.9% sodium, in a static test tube at 37°C temperature. Two samples were placed in 100 ml of 0.9% saline solution in a 250 ml stirring beaker with an average whirlpool depth of 1”. Two of each sample …
Improving Cardiovascular Stent Design Using Patient-Specific Models And Shape Optimization, Timothy J. Gundert
Improving Cardiovascular Stent Design Using Patient-Specific Models And Shape Optimization, Timothy J. Gundert
Master's Theses (2009 -)
Stent geometry influences local hemodynamic alterations (i.e. the forces moving blood through the cardiovascular system) associated with adverse clinical outcomes. Computational fluid dynamics (CFD) is frequently used to quantify stent-induced hemodynamic disturbances, but previous CFD studies have relied on simplified device or vascular representations. Additionally, efforts to minimize stent-induced hemodynamic disturbances using CFD models often only compare a small number of possible stent geometries. This thesis describes methods for modeling commercial stents in patient-specific vessels along with computational techniques for determining optimal stent geometries that address the limitations of previous studies.
An efficient and robust method was developed for virtually …
Image-Based Quantification Workflow For Coronary Morphology: A Tool For Use In Next-Generation Bifurcation Stent Design, Sara Marie Nomeland
Image-Based Quantification Workflow For Coronary Morphology: A Tool For Use In Next-Generation Bifurcation Stent Design, Sara Marie Nomeland
Master's Theses (2009 -)
Coronary artery disease (CAD) occurs in ~200,000 bifurcation lesions annually. Treatment of CAD near bends and bifurcations is challenging and a preferred strategy for bifurcation lesions has yet to be established. However, a favorable treatment option may be elucidated by a more thorough understanding of vessel morphology as well as local hemodynamic alterations caused by current stenting approaches. Computational modeling of human arteries offers an attractive way to investigate the relationships between geometry, hemodynamics and vascular disease. Recent developments also make it possible to perform analysis on realistic geometries acquired noninvasively.
The objective of this work was twofold. The first …
Design And Optimization Of A Blood Vessel Mimic Bioreactor System For The Evaluation Of Intravascular Devices In Simple And Complex Vessel Geometries, Sara M. Leifer
Master's Theses
Coronary artery disease affects millions of people and the ability to detect and treat the disease is advancing at a rapid rate. As a result, the development of intravascular technologies is the focus of many medical device manufacturers. Specifically, coronary stent implantation is being performed in an increasing number of patients and a number of new stent designs have been introduced to the market, resulting in the need for improved preclinical testing methods. An in vitro tissue engineered “blood vessel mimic” (BVM) system has previously been established and its feasibility for the initial testing of newly emerging intravascular technology has …