Heparin versus tirofiban in microvascular anastomosis: randomized controlled trial in a rat model.

Objective: Free flaps have become the mainstay of reconstruction after resection of head and neck cancer. Thrombosis after microvascular reanastamosis is a common reason for free flap failure. Various anticoagulants have been used topically and systemically to prevent thrombosis. Tirofiban is a glycoprotein IIb/IIIa inhibitor that prevents platelet aggregation and helps prevent thrombosis. The purpose of this study was to compare the thrombosis rate of topical heparin to topical heparin + tirofiban in a thrombogenic free flap model in rats.

Study Design: Prospective, randomized, double-blind, controlled trial.

Subjects And Methods: A thrombogenic free flap model was developed by raising a fasciocutaneous flap based on the epigastric artery in the Sprague-Dawley rat. An intimal flap was created proximal to the anastomosis site to increase thrombosis rates. Eighty rats were randomized to this thrombogenic free flap model using topical saline, heparin, or topical heparin + tirofiban. Each free flap was assessed for skin necrosis, capillary refill, and vessel thrombosis at 48 hours postprocedure. Data for each group were collected in a double-blind fashion.

Results: The heparin + tirofiban group had a 23% lower thrombosis rate and hence free flap failure rate when compared to the heparin alone group (p  =  .044).

Conclusions: The use of topical tirofiban in addition to topical heparin in microvascular surgery results in reduced rates of thrombosis and should be considered for use in head and neck oncology patients undergoing free flap reconstruction.