Influence of boundary conditions on fluid dynamics in models of the cardiovascular system: a multiscale approach applied to the carotid bifurcation

MOX 81

Influence of boundary conditions on fluid dynamics in models of the cardiovascular system: a multiscale approach applied to the carotid bifurcation

Monday 6th March 2006

Balossino, R., Pennati, G.; Migliavacca, F.; Formaggia, L.; Veneziani, A.; Tuveri, M.; Dubini, G.

Background: This work aims at addressing an important problem in the simulation of detailed 3D hemodynamic models of vascular districts with complex anatomy. Namely, to define appropriate boundary conditions accounting for both local as well as global effects. Approach: The approach devised in this work is based on a multiscale model, where the Navier-Stokes equations for the district of interest are coupled to a non-linear system of ordinary differential equations which describes the global circulatory system as a lumped parameter network. The multiscale approach is applied to three 3D models of a carotid bifurcation which differ only in the severity of a stenosis in the internal carotid artery. The results of the multiscale simulations are compared to those obtained by two stand-alone models of the carotid bifurcation, which differ in the adopted strategy in prescribing the boundary conditions. Results: Significant differences are found in the results between the multiscale and the stand-alone models in terms of flows, pressures and wall shear stresses distribution in the 3D domain. Conclusions: The capability to numerically predict the hemodynamic changes due to the presence of a stenosis is highly dependent on the availability of correct boundary conditions. The geometrical multiscale approach offers a logical and proper alternative to the use of measured data to prescribe realistic boundary conditions and predict new hemodynamic scenarios.