Ask Dr. Z

"The proximal left radial artery was used for inflow. It was heavily and circumferentially calcified, but was patent and did serve as effective inflow. The outflow was the first 2 cm of the left cephalic vein just upstream from the AV anastomosis. The cephalic vein fistula was dilated to greater than 1 cm and had excellent flow. The great saphenous vein was of good quality for a conduit and was harvested from the distal thigh and proximal calf and dilated to beyond 3 mm in diameter. Following the bypass, there was a good flow within the fistula and there was a weakly palpable thrill, and the bypass graft itself had an easily palpable thrill. The perianastomotic brachiocephalic arteriovenous fistula was ligated, and this was done between the arteriovenous anastomosis and the bypass graft anastomosis." The GSV was used as bypass from the radial artery to cephalic vein somewhat similar to a DRIL, but how would I code this?