Hemodynamics of In Situ Vein Bypass: the Role of Side Branch Fistulae

Ten patients undergoing femoral-popliteal and femoral-tibial in situ saphenous vein bypass for limb salvage were studied to determine the effects of side branch arteriovenous fistulae on flow through the distal end of the graft into the outflow artery. Studies were performed intraoperatively with electromagnetic flow probes. Following completion of proximal and distal anastomoses, flow was established through the graft and measured through its proximal and distal ends. Side branches were then ligated, and flow through the distal end of the graft measured again. Papaverine was administered and flow measured once more. Measured flows were consistent with those observed in previous studies, as were changes in flow induced by papaverine. Results indicate statistically significant diversion of blood through the fistulae, and a statistically significant increase in distal graft flow accompanying ligation of side branch fistulae. These data support the practice of routine side branch ligation during in situ bypass grafting.