A patient-specific FSI model for vascular access in haemodialysis

dc.contributor.advisorReddy, B Dayaen_ZA
dc.contributor.advisorMcBride, Andrew Trevoren_ZA
dc.contributor.authorDe Villiers, Anna Magdalenaen_ZA
dc.date.accessioned2017-06-01T10:05:49Z
dc.date.available2017-06-01T10:05:49Z
dc.date.issued2017en_ZA
dc.description.abstractThis research forms part of an interdisciplinary project that aims to improve the understanding of haemodynamics and vascular mechanics in arteriovenous shunting. To achieve the high flow rates that enable patients with renal disease to receive haemodialysis, a fistula is created between an artery and a vein. The patency rate of fistulas, especially those located in the upper arm, is low. The approach adopted here makes use of new magnetic resonance image (MRI) technology and computational modelling of blood flow, with a view to improving therapeutic strategies of disease requiring vascular interventions. This thesis presents the construction and development of a 3D finite element model of the fluid-structure interaction in a brachial–cephalic patient–specific fistula. An overview of the mathematical models that describe the vessel wall and fluid behaviour as well their interaction with each other is given. An Arbitrary Lagrangian- Eulerian (ALE) framework is used together with a transversely isotropic hyperelastic constitutive model for the vessel walls, while blood flow is modelled as a Newtonian fluid. A three-element Windkessel model is used to allow the fluid to move through the outlets of the computational domain without causing non–physical reflections. Flow data acquired from MRI is used to prescribe the flow at the inlet. The parameters of the Windkessel-model at the two outlets are calibrated to resemble the flow acquired from the 2D MRI. The model is validated against the flow patterns acquired from the 4D MRI. The flow patterns of the blood, and stress present in the vessel are investigated. Of special significance are the flow and wall shear stress at the anastomosis. An area of very high velocity in the anastomosis is followed by an area of recirculation and low velocity. The propagation of pressure waves and their reflection at the anastomosis are studied. Areas that are subjected to low wall shear stress, high oscillatory wall shear stress or flow circulation are identified as areas where intimal hyperplasia may develop. The flow results from the simulation show good qualitative agreement with the MRI data.en_ZA
dc.identifier.apacitationDe Villiers, A. M. (2017). <i>A patient-specific FSI model for vascular access in haemodialysis</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Research in Computational and Applied Mechanics (CERECAM). Retrieved from http://hdl.handle.net/11427/24441en_ZA
dc.identifier.chicagocitationDe Villiers, Anna Magdalena. <i>"A patient-specific FSI model for vascular access in haemodialysis."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Research in Computational and Applied Mechanics (CERECAM), 2017. http://hdl.handle.net/11427/24441en_ZA
dc.identifier.citationDe Villiers, A. 2017. A patient-specific FSI model for vascular access in haemodialysis. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - De Villiers, Anna Magdalena AB - This research forms part of an interdisciplinary project that aims to improve the understanding of haemodynamics and vascular mechanics in arteriovenous shunting. To achieve the high flow rates that enable patients with renal disease to receive haemodialysis, a fistula is created between an artery and a vein. The patency rate of fistulas, especially those located in the upper arm, is low. The approach adopted here makes use of new magnetic resonance image (MRI) technology and computational modelling of blood flow, with a view to improving therapeutic strategies of disease requiring vascular interventions. This thesis presents the construction and development of a 3D finite element model of the fluid-structure interaction in a brachial–cephalic patient–specific fistula. An overview of the mathematical models that describe the vessel wall and fluid behaviour as well their interaction with each other is given. An Arbitrary Lagrangian- Eulerian (ALE) framework is used together with a transversely isotropic hyperelastic constitutive model for the vessel walls, while blood flow is modelled as a Newtonian fluid. A three-element Windkessel model is used to allow the fluid to move through the outlets of the computational domain without causing non–physical reflections. Flow data acquired from MRI is used to prescribe the flow at the inlet. The parameters of the Windkessel-model at the two outlets are calibrated to resemble the flow acquired from the 2D MRI. The model is validated against the flow patterns acquired from the 4D MRI. The flow patterns of the blood, and stress present in the vessel are investigated. Of special significance are the flow and wall shear stress at the anastomosis. An area of very high velocity in the anastomosis is followed by an area of recirculation and low velocity. The propagation of pressure waves and their reflection at the anastomosis are studied. Areas that are subjected to low wall shear stress, high oscillatory wall shear stress or flow circulation are identified as areas where intimal hyperplasia may develop. The flow results from the simulation show good qualitative agreement with the MRI data. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - A patient-specific FSI model for vascular access in haemodialysis TI - A patient-specific FSI model for vascular access in haemodialysis UR - http://hdl.handle.net/11427/24441 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/24441
dc.identifier.vancouvercitationDe Villiers AM. A patient-specific FSI model for vascular access in haemodialysis. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Research in Computational and Applied Mechanics (CERECAM), 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/24441en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentCentre for Research in Computational and Applied Mechanics (CERECAM)en_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherHaemodynamicsen_ZA
dc.subject.otherVascular Mechanicsen_ZA
dc.titleA patient-specific FSI model for vascular access in haemodialysisen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
thesis_ebe_2017_de_villiers_anna_magdalena.pdf
Size:
17.41 MB
Format:
Adobe Portable Document Format
Description:
Collections