Holographic velocimetry: an alternative approach for flow characterization of prosthetic heart valves.

In vitro techniques for evaluating circulation through prosthetic heart valves can yield important information concerning valve performance prior to implantation. Laser Doppler velocimetry is the most widely accepted noninvasive flow measurement technique, however, its use is somewhat limited for flow mapping applications. Holographic velocimetry is an alternative noninvasive in vitro approach for flow diagnostics. The advantage of this technique is the ability to do instantaneous full volume measurements for complete three-dimensional flow mapping at any instant in a flow cycle. Holographic velocimetry was used for the evaluation of circulation through a ball and cage valve. Results indicate that just beyond the apex of the cage very low velocity exists in the mean flow direction, while the other two components of velocity are rather large. Studies done further downstream from the valve begin to show the flow characteristics returning to the state of fully developed turbulent flow, as was previously seen upstream from the valve housing.