title: Comparison of vortical structures induced by arteriovenous grafts using vector Doppler ultrasound.
abstract: Arteriovenous prosthetic grafts are used in hemodialysis. Stenosis in the venous anastomosis is the main cause of occlusion and the role of local hemodynamics in this is considered significant. A new spiral graft design has been proposed to stabilize the flow phenomena in the host vein. Cross-flow vortical structures in the outflow of this graft were compared with those from a control device. Both grafts were integrated in identical in-house ultrasound-compatible flow phantoms with realistic surgical configurations. Constant flow rates were applied. In-plane 2-D velocity and vorticity mapping was developed using a vector Doppler technique. One or two vortices were detected for the spiral graft and two to four for the control, along with reduced stagnation points for the former. The in-plane peak velocity and circulation were calculated and found to be greater for the spiral device, implying increased in-plane mixing, which is believed to inhibit thrombosis and neo-intimal hyperplasia.
authors: Institute for Medical Science and Technology, University of Dundee, Dundee, UK; Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK. Electronic address: E.Kokkalis@dundee.ac.uk.
authors: Efstratios
authors: E
authors: Kokkalis
authors: Department of Biomedical Engineering, King's College London, London, UK.
authors: Andrew N
authors: AN
authors: Cookson
authors: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK.
authors: Peter A
authors: PA
authors: Stonebridge
authors: Medical Physics, Ninewells Hospital and Medical School, Dundee, UK.
authors: George A
authors: GA
authors: Corner
authors: Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK.
authors: J Graeme
authors: JG
authors: Houston
authors: Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK.
authors: Peter R
authors: PR
authors: Hoskins
mesh_terms: D001166:Arteriovenous Shunt, Surgical; D001807:Blood Vessel Prosthesis; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D019047:Phantoms, Imaging; D006435:Renal Dialysis / Q000295:instrumentation*; D018608:Ultrasonography, Doppler; D018615:Ultrasonography, Doppler, Color
keywords: Arteriovenous prosthetic grafts; Circulation; Color Doppler; Flow mixing and stagnation; Flow phantom; Spiral flow; Vector Doppler ultrasound; Velocity; Vortical structures; Vorticity