Laser Doppler velocimetry and flow visualization studies in the regurgitant leakage flow region of three mechanical mitral valves

Streak line flow visualization and laser Doppler velocimetry (LDV) were con ducted in the regurgitant leakage flow region of 3 mechanical heart valve t ypes: CarboMedics, Medtronic Hall, and St. Jude Medical. Streak line flow v isualization identified regions of high regurgitant flow, and LDV measureme nts were focused on those locations. Maximum regurgitant flow velocities af ter valve closure ranged from 0.7 to 2.6 m/s, and maximum Reynolds shear st ress after valve closure ranged from 450 to 3,600 dyne/cm(2). These data in dicate that leakage flows can generate turbulent jets with elevated Reynold s stresses even in bileaflet valves.