Monodimensional Estimation of Maximum Reynolds Shear Stress in the Downstream Flow Field of Bileaflet Valves
Mauro Grigioni MS, Carla Daniele MS, Giuseppe DÕAvenio MS, Vincenzo Barbaro MS

Turbulence in blood flow can have adverse consequences, such as hemolysis, for the health of prosthesis recipients. Measurement of the complete Reynolds stress tensor, due to the three-dimensional nature of turbulence, may be performed to evaluate the maximum load on blood constituents, but this is difficult in vivo. In the present study, the maximum Reynolds shear stress (RSS) in three commercially available prosthetic heart valves (PHVs) of wide diffusion was derived, starting monodimensional data obtained in vivo, using echo Doppler. By using accurate laser Doppler anemometry (LDA) measurements, the relationship between maximum RSS and Reynolds normal stress in the main flow direction was calculated. This may prove valuable during the post-implantation phase, when the assessment of valve function is performed echocardiographically. Hence, both the risk of damage to blood constituents, and any eventual valve dysfunction, may be estimated accurately in vivo.