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Author(s): E. Doutel
S. I. S. Pinto
J. B. L. M. Campos
J. M Miranda
Title: Link between deviations from Murray's Law and occurrence of low wall shear stress regions in the left coronary artery
Issue Date: 2016
Abstract: Murray developed two laws for the geometry of bifurcations in the circulatory system. Based on theprinciple of energy minimization, Murray found restrictions for the relation between the diameters andalso between the angles of the branches. It is known that bifurcations are prone to the development ofatherosclerosis, in regions associated to low wall shear stresses (WSS) and high oscillatory shear index(OSI). These indicators (size of low WSS regions, size of high OSI regions and size of high helicity regions)were evaluated in this work. All of them were normalized by the size of the outflow branches. Therelation between Murrays laws and the size of low WSS regions was analysed in detail. It was found thatthe main factor leading to large regions of low WSS is the so called expansion ratio, a relation betweenthe cross section areas of the outflow branches and the cross section area of the main branch. Largeregions of low WSS appear for high expansion ratios. Furthermore, the size of low WSS regions is independentof the ratio between the diameters of the outflow branches. Since the expansion ratio inbifurcations following Murrays law is kept in a small range (1 and 1.25), all of them have regions of lowWSS with similar size. However, the expansion ratio is not small enough to completely prevent regionswith low WSS values and, therefore, Murrays law does not lead to atherosclerosis minimization. A studyon the effect of the angulation of the bifurcation suggests that the Murrays law for the angles does notminimize the size of low WSS regions.
Subject: Engenharia mecânica, Engenharia mecânica
Mechanical engineering, Mechanical engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia mecânica
Engineering and technology::Mechanical engineering
Related Information: info:eu-repo/grantAgreement/Autoriadade de Gestão do Programa Operacional Regional do Norte/Programas Integrados de IC&DT/NORTE-07-0124-FEDER-000025/(Bio) Chemical Engineering: Multi-Scale Approaches for Sustainable Environment and Health/LEPAE/CEFT - RL2
info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projectos de I&DT em Todos os Domínios Científicos/PTDC/EME-MFE/102974/2008/Estudo numérico e experimental do escoamento de sangue no interior de stents implantados em artérias/PTDC/EME-MFE/102974/2008
info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/PEst-OE/EME/UI0532/2013/PROJECTO ESTRATÉGICO - UI 532 - 2013-2014/UI0532
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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