The influence of out-of-plane geometry on the flow within a distal end-to-side anastomosis

This paper describes a computational and experimental investigation of flow in a proto-type model geometry, of a fully occluded 45 deg distal end-to-s ide anastomosis. Previous investigations have considered a similar configur ation where the centerlines of the bypass and host vessels lie within a pla ne, thereby producing a plane of symmetry within the flow. We have extended these investigations by deforming the bypass vessel out of the plane of sy mmetry, thereby breaking the symmetry of the flow and producing a nonplanar geometry. Experimental data were obtained using magnetic resonance imaging of flow within perspex models and computational data were obtained from si mulations using a high-order spectral/hp element method. We found that the nonplanar three-dimensional flow notably alters the distribution of wall sh ear stress at the bed of the anastomosis, reducing the peak wall shear stre ss peak by approximately 10 percent when compared with the planar model. Fu rthermore, an increase in the absolute flux of velocity into the occluded r egion, proximal to the anastomosis, of 80 percent was observed in the nonpl anar geometry when compared with the planar geometry. [S0148-0731(00)00401- 5].