title: Effect of physiological factors on proximal flow convergence upstream of an incompetent valve: an in-vitro study.
abstract: The flow (Q) through regurgitant valves may be quantified by multiplying the area of an isovelocity contour (isovel) by its velocity. This was tested computationally and experimentally (using MRI). Q = 14 to 141 ml/s, using flat and conical orifice plates. Plotting Q versus isovelocity radius, a plateau was found which, for low flow, corresponded to the true Q. At higher flow or large confinement, Q was overestimated. For conical plates, angle correction worked at low Q but not at higher values due to the formation of separation regions. These converted the cone plate into a flat plate. MRI produced similar results at 57 ml/s in that Q was correct with no angle correction. At low flow, MRI was too noisy to produce a clear plateau consistently.
authors.affiliation: Cardiovascular Fluid Mechanics Laboratory, School of Chemical Engineering, Georgia Institute of Technology, Atlanta 30332-0100, USA.
authors.forename: F S
authors.initials: FS
authors.lastname: Guenet
authors.forename: P G
authors.initials: PG
authors.lastname: Walker
authors.forename: M W
authors.initials: MW
authors.lastname: Doyle
authors.forename: G M
authors.initials: GM
authors.lastname: Pohost
authors.forename: A P
authors.initials: AP
authors.lastname: Yoganathan
mesh_terms: D001022:Aortic Valve Insufficiency / Q000175:diagnosis / Q000503:physiopathology*; D015982:Bias; D001783:Blood Flow Velocity; D003198:Computer Simulation; D018056:Hemorheology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012984:Software