Ask Dr. Z

"The surgeon created a femoral to tibial artery bypass with in-situ saphenous vein conduit. The surgeon then accessed the hood of the femoral anastomosis with a micropuncture needle, wire, and sheath. A right leg runoff angiogram was done, which demonstrated three large AV fistulae. These were marked, skin cutdowns made over each, and the offending venous tributary ligated with clips in each zone. Repeat, completion angiogram showed no further AV communications; the graft pulse improved markedly. Each cutdown was now in layers and skin glue applied."  What would I code for the AVF ligations?