General Surgery Coding Alert

Question: A week following creation of an AV fistula, the surgeon had to perform a thrombectomy to remove a clot. May I report the thrombectomy separately, or is it included in the global period of the AV fistula? Maryland Subscriber Answer: Your payer should allow separate payment for thrombectomy during the 90-day global period of an arteriovenous (AV) fistula creation. For thrombectomy only, you should claim 36831 (Thrombectomy, open, arteriovenous fistula without revision, autogenous or nonautogenous dialysis graft [separate procedure]). If the surgeon revises/resects the fistula at the same time as the thrombectomy, you should instead report 36833 (Revision, open, arteriovenous fistula; with thrombectomy, autogenous or nonautogenous dialysis graft [separate procedure]). Append modifier 79 (Unrelated procedure or service by the same physician during the postoperative period) to your chosen code to show the payer that the thrombectomy was not related to creation of the fistula (although both procedures are related to the patient's renal failure). Finally, link a diagnosis of 996.73 (Other complications of internal [biological] [synthetic] prosthetic device, implant and graft; due to renal dialysis device, implant and graft) to the thrombectomy code to justify the need for the procedure.