Stenosis-induced flow disturbances in an artery segment assessed by numerical simulation

The origin of sounds detectable in arteries with serious stenosis is still a questionable matter. To explore the hypothesis that stenosis-induced flow disturbances may be the cause of vascular sounds we numerically simulated the onset of flow oscillations in a vessel with a severe constriction. The model, based on the axi-symmetric Navier-Stokes equations, includes fluid non-linear inertial forces, viscoelastic wall motion, anatomical taper and reflexion in the vessel extremities due to proximal and distal circulations. By this model unstable circulations and self-excited flow oscillations were reproduced. Depending on the steady entry blood flow level in the stenotic artery segment different flow oscillatory patterns were simulated. A common characteristic of such flow oscillations was an high frequency component in the audible band (550 Hz). Thus, results support the hypothesis that vascular sounds may be generated by high frequency flow oscillations.