General Surgery Coding Alert

Question: The surgeon created an AV fistula in a renal-failure patient. Within a week, the surgeon had to perform a thrombectomy to remove a clot. Will the payer reimburse us for the thrombectomy performed during the global period of the AV fistula?

Maryland Subscriber Answer: Yes, the payer should allow separate payment for thrombectomy during the 90-day global period of an arteriovenous (AV) fistula.

To claim thrombectomy only, report 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, report 36833 (Revision, open, arteriovenous fistula; with thrombectomy, autogenous or nonautogenous dialysis graft [separate procedure]) instead of 36831.

In either case, you should append modifier -79 (Unrelated procedure or service by the same physician during the postoperative period) to the thrombectomy code to show the payer that the thrombectomy was not related to creation of the fistula (even though both procedures are related to the patient's renal failure).

And, you should 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.