EFFECT OF PHYSIOLOGICAL FACTORS ON PROXIMAL FLOW CONVERGENCE UPSTREAMOF AN INCOMPETENT VALVE - AN IN-VITRO STUDY

The flow (Q) through regurgitant valves may be quantified by multiplyi ng the area of an isovelocity contour (isovel) by its velocity. This w as tested computationally and experimentally (using MRI), Q = 14 to 14 1 ml/s, using flat and conical orifice plates, Plotting Q versus isove locity radius, a plateau was found which, for low flow, corresponded t o the true Q. At higher flow or large confinement, Q was overestimated . For conical plates, angle correction worked at low Q but not at high er values due to the formation of separation regions. These converted the cone plate into a pat plate. MRI produced similar results at 57 ml /s in that Q was correct with no angle correction. At low pow, MRI was too noisy to produce a clear plateau consistently.