Analysis of Stent-Graft Design for Aortic Aneurysm Repair Using Computational Fluid Dynamics1

Suess, Taylor N.; Gent, Stephen P.; Remund, Tyler; Kelly, Patrick

doi:10.1115/1.4030574

Cited by 3 publications

(4 citation statements)

References 4 publications

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“…TAWSS is measured in Pascals, and a value below 0.4 Pa slows down nutrient renewal, while TAWSS above 7.0 Pa can cause endothelial damage. High localized TAWSS is likely to trigger clotting [16]. TAWSS is important to this study because it will tell if there is a difference in the WSS values between rigid and deformable walls in the CFD models, and it has major implications on possible blood flow problems.…”

Section: Parameters Of Interestmentioning

confidence: 99%

Examination of Fluid-Structure Interaction in Stent Grafts and its Hemodynamic Implications

Looyenga

Gent

2018

2018 Design of Medical Devices Conference

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Every year in the United States, 4,500 deaths occur from abdominal aortic aneurysm (AAA) rupture. Aneurysms develop when the arterial wall weakens. Many risk factors can contribute to aneurysm formation, including age, sex, ethnicity, smoking and hypertension [1]. AAAs are the most common form of aneurysm because the aorta experiences the highest wall shear stress (WSS) of any vessels in the human body. These aneurysms are 5–6% prevalent in men and 1–2% in women, both over 65 years of age [2]. In the aorta, high WSS causes plaque formation, but in peripheral arteries where the flow rate is lower, atherosclerosis can also trigger aneurysm formation.

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Section: Parameters Of Interestmentioning

confidence: 99%

Examination of Fluid-Structure Interaction in Stent Grafts and its Hemodynamic Implications

Looyenga

Gent

2018

2018 Design of Medical Devices Conference

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“…Time-average wall shear stress (TAWSS) measures the averaged stress impacted on the walls of the artery and along the branches of the LAD. Values of TAWSS greater than 7 Pa have been reported to lead to endothelial damages and plaque rupture, while values of TAWSS less than 0.4 Pa can result in delayed nutrient and waste removal from the artery [4].…”

Section: Fig 1: Cad Models For Three Of the Five Geometries Evaluatedmentioning

confidence: 99%

“…OSI greater than 0.3 has been reported to lead to atherosclerosis formation. OSI of zero indicates unidirectional flow, which is ideal for cardiovascular flow [4].…”

Section: Fig 1: Cad Models For Three Of the Five Geometries Evaluatedmentioning

confidence: 99%

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Hemodynamics Study of Different Take-Off Angles of the Left Coronary Artery

Asiruwa

Propst

Gent

2017

2017 Design of Medical Devices Conference

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Coronary arteries are located on the surface of the heart and supply oxygenated blood to the myocardium and other components of the heart. The two coronary arteries located above the aortic arch are the Left Coronary Artery (LCA) and Right Coronary Artery (RCA). The LCA branches into the Left Anterior Descending (LAD) and the Left Circumflex (LCx) while the RCA branches into the Right Marginal Artery (RMA) and Post Descending Artery (PDA). The coronary arteries are likened to a complex tube-like structure, and the motion of the heart cause changes in pressure, which allows proper blood circulation during the systolic and diastolic phases [1]. Since it is essential to understand the physiological and hemodynamical behavior of the heart and coronary arteries, numerous studies have been conducted at different artery locations in the heart. Most of the research has focused on the branches between the LAD and LCx, with little or no attention directed towards the take-off angle the LCA makes with the aortic root. Although it has been reported that certain take-off angles of left main (LM) can be considered anomalous, findings have documented that such take off angles can make the artery prone to atherosclerosis and sudanophilia diseases [2]. Computational Fluid Dynamics (CFD) has in recent years been used to solve a wide variety of fluid flow challenges, and can be used for this study. The goal of this study is to use CFD techniques to study the hemodynamics of the different take-off angles of the left coronary artery from the aortic root. This will help identify areas in the left coronary artery that could be prone to atherosclerosis buildup.

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Measurement of Frictional Properties of Aortic Stent Grafts and Their Delivery Systems

Chen

Lancaster

Lin

et al. 2019

Journal of Medical Devices

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Stent grafts are medical devices used to treat abdominal aortic aneurysms (AAAs) in endovascular aneurysm repair (EVAR). Computational and experimental models have been developed to study stent graft delivery and deployment during EVAR; however, frictional properties have not been taken into account in most previous studies. The objective of this study was to determine the coefficients of friction of three commercially available stent grafts (Cook Zenith, Medtronic Endurant, and Vascutek Anaconda), their delivery sheaths, a porcine aorta, and two mock arterial materials. Stent grafts were obtained and separated into stents, graft fabric, and sheaths. Using a custom-made friction measurement apparatus, the coefficients of friction were measured between five material pairs: (i) the stents and inner surface of the sheath, (ii) the graft fabric and inner surface of the sheath, (iii) the outer surface of the sheath and a porcine aorta, (iv) the outer surface of the sheath and three different polyvinyl alcohol (PVA) cryogels, and (v) the outer surface of the sheath and a polydimethylsiloxane (PDMS) sheet. The results show that the coefficients of friction between the graft fabric and the sheath were higher than those between the stents and the sheath. The PVA cryogels showed more comparable frictional properties to the porcine aorta than did the PDMS sheet, suggesting that PVA cryogels provide a more accurate approximation for the in vivo frictional properties. These results can be used to improve the accuracy of computational models for stent graft delivery and deployment and to select appropriate materials for vascular phantoms.

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Analysis of Stent-Graft Design for Aortic Aneurysm Repair Using Computational Fluid Dynamics1

Cited by 3 publications

References 4 publications

Examination of Fluid-Structure Interaction in Stent Grafts and its Hemodynamic Implications

Examination of Fluid-Structure Interaction in Stent Grafts and its Hemodynamic Implications

Hemodynamics Study of Different Take-Off Angles of the Left Coronary Artery

Measurement of Frictional Properties of Aortic Stent Grafts and Their Delivery Systems

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