title: Digital particle image velocimetry (DPIV) measurements of the velocity profiles through bileaflet mechanical valves: in vitro steady.
abstract: Although velocity profiles downstream of mechanical valves have been measured in-vitro using Laser Doppler Anemometry (LDA), these studies have not measured velocities in the immediate proximity of the leaflets since the LDA technique prevents velocities from being measured in the immediate vicinity of any structure. Laser based Digital Particle Image Velocimetry (DPIV) is a new technique that allows for accurate measurement of an entire two-dimensional velocity field with no beam angulation. DPIV was used to measure two-component velocity vectors immediately proximal and distal to a 25 mm bileaflet mechanical valve (St. Jude) mounted in a transparent steady flow in-vitro model. Measurements of flow similar in Reynolds number (Re) to mitral inflow (Re = 2000-4000) showed clear hemi-elliptical isovelocity convergence zones proximal to each of the three orifices. DPIV measurements of flow distal to the orifice revealed clear vortex rollups generated from the internal ring of the valve with separate velocity profiles immediately distal to the leaflets. These studies prove the feasibility of the DPIV technique to provide accurate velocity measurements of flow profiles through mechanical valves.
authors.affiliation: Dept. of Cardiology, Children's Hospital, Denver, CO 80218, USA.
authors.forename: R
authors.initials: R
authors.lastname: Shandas
authors.forename: J
authors.initials: J
authors.lastname: Kwon
mesh_terms: D001783:Blood Flow Velocity; D006350:Heart Valve Prosthesis; D018056:Hemorheology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D017078:Laser-Doppler Flowmetry