Ask Dr. Z

I thought I had this figured out but I need to clarify. I always coded a fistula anastomosis plasty to an arterial. But then reading up in your book, you state that there are both venous anastomosis and arterial anastomsis in a graft. You also state we should code arterial anastomosis or perianastomotic region angioplasty to an arterial 35475/75962. If the physician states that the angioplasty is of the anastomosis,how do you know if it was arterial or venous anastomosis? Does it matter? Do all anastomotic strictures of the fistula automatically get an arterial angioplasty code assigment?