GEOMETRIC DESIGN IMPROVEMENTS FOR FEMORAL GRAFT-ARTERY JUNCTIONS MITIGATING RESTENOSIS

The present study is based on the hypothesis that nonuniform hemodynam ics, represented by large time-averaged wall shear stress gradients, t rigger abnormal biological processes leading to rapid restenosis, i.e. excessive tissue overgrowth and renewed plaque formation, and hence e arly graft failure. It implies that this problem may be significantly mitigated by finding graft-artery bypass configurations for which the wall shear stress gradient is approximately zero and hence nearly unif orm hemodynamics is achieved. These fluid flow and geometric design co nsiderations are applied to four different end-to-side anastomoses for the distal end of a femoral artery bypass with an appropriate rest in put pulse and a typical 20-80 flow division. A validated finite-volume code has been used to compute the transient three-dimensional velocit y vector fields, wall shear stress distributions and surface contours of the wall shear stress gradients. It is shown that large anastomotic flow areas, small continuously changing bifurcation angles, and smoot h junction wall curvatures reduce local time-averaged wall shear stres s gradients significantly and hence should mitigate restenosis. Copyri ght (C) 1996 Elsevier Science Ltd.