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Arteriovenous Conduits for Hemodialysis: How to Better Modulate the Pathophysiological Vascular Response to Optimize Vascular Access Durability

Yan-Ting Shiu, Joris I. Rotmans, Wouter Jan Geelhoed, Daniel B Pike, Timmy Lee
2019 AJP - Renal Physiology  
Arteriovenous grafts (AVGs) are the next preferred vascular access when an AVF creation is not possible.  ...  Arteriovenous fistulas (AVFs) are the preferred vascular access, but AVF maturation failure remains a significant clinical problem.  ...  In contrast, disturbed, oscillatory, and low fluid-wall shear stress often occurs at sites of vascular bifurcation in native arteries or the graft-arterial anastomosis in bypass grafts.  ... 
doi:10.1152/ajprenal.00440.2018 pmid:30785348 pmcid:PMC6580244 fatcat:pm5m5bakhrcfdd6vuefxx2saza

A computational framework for derivative-free optimization of cardiovascular geometries

Alison L. Marsden, Jeffrey A. Feinstein, Charles A. Taylor
2008 Computer Methods in Applied Mechanics and Engineering  
In this method, we employ a derivative-free approach using surrogates for increased efficiency together with mesh adaptive direct search to guarantee convergence to a local minimum.  ...  Predictive simulation and optimization-based design tools have great potential to improve the design of surgeries and interventions used in cardiovascular medicine.  ...  In defining a cost function for this problem, our goal is to reduce localized areas of low wall shear stress.  ... 
doi:10.1016/j.cma.2007.12.009 fatcat:6anpyqnd25dfpbc2yjgercysry

Recent advances in the application of computational mechanics to the diagnosis and treatment of cardiovascular disease

Juan C Del Alamo, Alison L Marsden, Juan C Lasheras
2009 Revista Española de Cardiología  
Ongoing improvements in the spatial resolution of medical imaging equipment coupled to an exponential growth in the capacity, flexibility and speed of computational techniques have provided a valuable  ...  During the last 30 years, research into the pathogenesis and progression of cardiovascular disease has had to employ a multidisciplinary approach involving a wide range of subject areas, from molecular  ...  aorta causing an increase in wall stresses.  ... 
pmid:19709514 pmcid:PMC6089365 fatcat:kw6aoncesna4nnihuoi7z2wche

The impact of uncertainty on shape optimization of idealized bypass graft models in unsteady flow

Sethuraman Sankaran, Alison L. Marsden
2010 Physics of Fluids  
Changes in the downstream ͑distal͒ graft angle resulted in greater sensitivity of the wall-shear stress compared to changes in the upstream ͑proximal͒ angle.  ...  Two idealized numerical examples, an end-to-side anastomosis, and a bypass graft around a stenosis, demonstrate that accounting for uncertainty significantly changes the optimal graft design.  ...  ACKNOWLEDGMENTS The work was supported by an American Heart Association Beginning Grant in Aid award and Burroughs Wellcome Fund Career Award at the Scientific Interface and a Leducq Foundation Transatlantic  ... 
doi:10.1063/1.3529444 fatcat:ry6en56eyzdp7dp4q7tktouvba

MicroRNAs in flow-dependent vascular remodelling

Peter Neth, Maliheh Nazari-Jahantigh, Andreas Schober, Christian Weber
2013 Cardiovascular Research  
in a pathological EC phenotype.  ...  The development and structure of blood vessels are highly adapted to haemodynamic forces, such as shear stress, cyclic stretch, and circumferential wall stress, generated by the conductance of blood.  ...  cues. 2 ECs are primarily exposed to the laminar flow, which generates a mean wall shear stress of 15 dyn/cm 2 in the arterial system, although the actual values may considerably vary in different locations  ... 
doi:10.1093/cvr/cvt096 pmid:23612583 fatcat:ir3s2upeurbpjndad2qk6keore

Endothelial Cell Seeding of Small Diameter Vascular Grafts

N. L. James, K. Schindhelm, P. Slowiaczek, B. K. Milthorpe, N. P. B. Dudman, G. Johnson, J. G. Steele
1990 Artificial Organs  
Endothelial cell retention was examined in an in vitro flow test at physiologically relevant shear stress levels for 50 min.  ...  An ex vivo carotid-jugular shunt was used to expose grafts lined with autologous ovine endothelial cells to blood flow of 150 ml min-1 (2.7 N m-2 mean shear stress) for 3 hours.  ...  Shear stress In vivo measurement of shear stress on the wall of an artery is very difficult since it requires specially constructed probes which also affect the flow pattem (Ling et al., 1968) .  ... 
doi:10.1111/j.1525-1594.1990.tb02980.x pmid:2241603 fatcat:pkal3srglfaazk3ad6nee3dtzu

The Role of Biofluid Mechanics in the Assessment of Clinical and Pathological Observations

Maria Siebes, Yiannis Ventikos
2010 Annals of Biomedical Engineering  
When combined with underlying physiological models, a powerful set of tools becomes available to address unmet clinical needs, predominantly in the direction of enhanced diagnosis, as well as assessment  ...  This position paper presents an overview of current approaches and future developments along this theme that were discussed at the 5th International Biofluid Symposium and Workshop held at the California  ...  stented bioprosthetic valves resulted in a large increase in peak wall shear stress on the leaflets with advanced degeneration.  ... 
doi:10.1007/s10439-010-9903-y pmid:20087774 pmcid:PMC2841261 fatcat:snaw4qa22vhiloatikwafdvmsi

SIMCor. Deliverable 7.2: Definition of model templates (TUE, M9)

Wouter Huberts
2021 Zenodo  
The document gives an overview of the available models for simulating the physiology of these patient groups, both before and after transcatheter aortic valve implantation or insertion of a pulmonary artery  ...  In addition, it describes the intended use of these models.  ...  More recently, we have adopted this agPCE approach for the optimization of an arteriovenous graft by using the surrogate model for predicting how different helical graft design parameter settings translate  ... 
doi:10.5281/zenodo.6146528 fatcat:r3ffyxymwvgm3n34q7zt7jho6e

Artificial Intelligence for Developing Tools and Technologies in Vascular and Cardiac Surgery Applications: A Survey

Miltiadis Alamaniotis
2021 American Journal of Biomedical Science & Research  
An advanced technique for diagnosis of AAA, has already demonstrated the ability to autonomously analyze computational fluid dynamic data and calculate wall shear stresses [22] .  ...  Results from such an approach provided a high prediction accuracy independent of the number of weights used to model the neural network [8] .  ... 
doi:10.34297/ajbsr.2021.12.001738 fatcat:aikb33zci5dgrkik5toqcpf3mm

Dissipative particle dynamics simulation of flow generated by two rotating concentric cylinders: II. Lateral dissipative and random forces

N Filipovic, S Haber, M Kojic, A Tsuda
2008 Journal of Physics D: Applied Physics  
Filipovic, Data mininig application in the wall shear stress distribution prediction for aneurysm and carotid bifurcation models, Congress on Theoretical and Applied Mechanics, Vlasina Lake, 2011, 5-8  ...  G Jovicic, A Vukicevic, N Filipovic, Computational Assessment of Stent Durability Using Fatigue to Fracture Approach, Journal of Medical Devices, Vol.-, No.-, pp. -, ISSN 1932-6181, Doi 10.1115/1.4027687  ... 
doi:10.1088/0022-3727/41/3/035504 fatcat:rjvvejj2rzh4nnzxllzvrk3chu

A Road Map for Computational Surgery: Challenges and Opportunities [chapter]

B. L. Bass, M. Garbey
2013 Computational Surgery and Dual Training  
We believe that this new collaboration will allow the community not only to develop predictive models for the outcomes of surgery but also to enhance the process of surgery -from procedural planning, to  ...  While some of the elements we present may be considered as basic for a specialized investigator, the simplicity of the presentation is intended as a proof of principle that basic concepts in computational  ...  Future opportunities include the visualization of the fluid shear stress in the arterial wall at the time of vascular reconstruction or determination of optimal energy delivery rate radio frequency ablation  ... 
doi:10.1007/978-1-4614-8648-0_1 fatcat:lasziamspfhchm7uv3tucjkh5m

A road map for computational surgery: challenges and opportunities

Barbara Bass, Marc Garbey
2014 Journal of Computational Surgery  
We believe that this new collaboration will allow the community not only to develop predictive models for the outcomes of surgery but also to enhance the process of surgery -from procedural planning, to  ...  While some of the elements we present may be considered as basic for a specialized investigator, the simplicity of the presentation is intended as a proof of principle that basic concepts in computational  ...  Future opportunities include the visualization of the fluid shear stress in the arterial wall at the time of vascular reconstruction or determination of optimal energy delivery rate radio frequency ablation  ... 
doi:10.1186/2194-3990-1-2 fatcat:rhxf4w7iibfxjcm64lohsxmjae

Young Investigators Awards

2007 Journal of the American College of Cardiology  
This is likely an important factor in the increased SCD risk in this time period, and may be the mechanism by which ßblockers reduce this risk. 9:45 a.m. 406-8 Background: A hallmark feature of atherosclerosis  ...  Conclusion: We have found the COX-2 G-765C polymorphism to be a risk factor for incident stroke in African-Americans.  ...  Furthermore, we demonstrate that endothelial KLF4 is induced by pro-inflammatory stimuli and shear stress.  ... 
doi:10.1016/j.jacc.2007.01.044 fatcat:h2bgr6sup5fvrkb7uccd65sqrq

Mathematical Modeling of the Vascular System

Ju Liu, Ingrid S Lan, Alison L Marsden
2021 Notices of the American Mathematical Society  
The cardiovascular system is a closed circuit in which the heart pumps blood from the left and right ventricles to the systemic and pulmonary circulations.  ...  The two circulations work synchronously to deliver oxygenated blood to the body and the heart itself and to route deoxygenated  ...  Furthermore, the hemodynamic wall shear stress (WSS) and pressure are two important mechanical loads dictating the G&R response of the vessel wall.  ... 
doi:10.1090/noti2278 fatcat:yvp3sbwq25ehfjarahxobcl7by

4th International Meeting on Aortic Diseases: New Insights into an Old Problem

Natzi Sakalihasan
2014 Aorta  
Managing these extra-aortic features in MFS requires adequate knowledge and a specific approach in some cases. These issues will be discussed in this presentation. References: 1. Hoffmann, B.  ...  Related to myocardial dysfunction to some extent, arrhythmias are more frequently documented in MFS patients and sudden arrhythmic death occurs more common than in the general population.  ...  SHEAR STRESS ON THE ASCENDING AORTIC WALL IN PATIENTS WITH A BICUSPID AORTIC VALVE Comparing the jet and control samples in both BAV and TAV, regions of maximal shear stress did not show any difference  ... 
doi:10.12945/j.aorta.2014.14.997 fatcat:i5ctmlyigndwzntvpco3nxnjpe
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