Effects of viscosity and constraints on the dispersion and dissipation of waves in large blood vessels. II. Comparison of analysis with experiments.

The theoretical predictions described in part I of this study are compared with in vivo data from anesthetized dogs. It is shown that the observed attenuation of the pressure and axial waves cannot be accounted for by fluid viscosity alone. For large values of the frequency parameter alpha = radicalrhoomegaR(2) (0)/mu, the analysis of part I is extended to include the effects of viscoelasticity of the vessel wall. The results indicate that the speeds of both types of waves are essentially not affected by a realistic viscoelasticity model while the attenuation per wavelength is significantly increased and becomes frequency independent. The application of this analysis to in vivo data from the carotid arteries of anesthetized dogs demonstrates partial agreement between theory and experiment and suggests that the carotid arteries are anisotropically viscoelastic.