title: Assessment of Hemodynamic Conditions in the Aorta Following Root Replacement with Composite Valve-Conduit Graft.
abstract: This paper presents the analysis of detailed hemodynamics in the aortas of four patients following replacement with a composite bio-prosthetic valve-conduit. Magnetic resonance image-based computational models were set up for each patient with boundary conditions comprising subject-specific three-dimensional inflow velocity profiles at the aortic root and central pressure waveform at the model outlet. Two normal subjects were also included for comparison. The purpose of the study was to investigate the effects of the valve-conduit on flow in the proximal and distal aorta. The results suggested that following the composite valve-conduit implantation, the vortical flow structure and hemodynamic parameters in the aorta were altered, with slightly reduced helical flow index, elevated wall shear stress and higher non-uniformity in wall shear compared to normal aortas. Inter-individual analysis revealed different hemodynamic conditions among the patients depending on the conduit configuration in the ascending aorta, which is a key factor in determining post-operative aortic flow. Introducing a natural curvature in the conduit to create a smooth transition between the conduit and native aorta may help prevent the occurrence of retrograde and recirculating flow in the aortic arch, which is particularly important when a large portion or the entire ascending aorta needs to be replaced.
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: Department of Surgery and Cancer, St. Mary's Hospital, Imperial College London, London, W2 1NY, UK.
authors.forename: Emaddin
authors.initials: E
authors.lastname: Kidher
authors.affiliation: Department of Surgery and Cancer, St. Mary's Hospital, Imperial College London, London, W2 1NY, UK.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Jarral
authors.affiliation: Institute of Clinical Science, Hammersmith Hospital, Imperial College London, London, W12 0HS, UK.
authors.forename: Declan P
authors.initials: DP
authors.lastname: O'Regan
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
authors.forename: Nigel B
authors.initials: NB
authors.lastname: Wood
authors.affiliation: Department of Surgery and Cancer, St. Mary's Hospital, Imperial College London, London, W2 1NY, UK.
authors.forename: Thanos
authors.initials: T
authors.lastname: Athanasiou
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK. yun.xu@imperial.ac.uk.
authors.forename: Xiao Yun
authors.initials: XY
authors.lastname: Xu
mesh_terms: D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D001783:Blood Flow Velocity; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged
keywords: Aortic root replacement; Computational fluid dynamics; Helical flow; Patient-specific modelling; Phase-contrast MRI; Wall shear stress