Safe and effective thrombolysis in free flap salvage: Intra-arterial urokinase infusion

Abstract

Despite the high success rate in reconstruction using free tissue transfer, flap failure is often caused by microvascular thrombosis. In a small percentage of cases with complete flap loss, a salvage procedure is performed. In the present study, the effectiveness of intra-arterial urokinase infusion through the free flap tissue was investigated to develop a protocol to prevent thrombotic failure. The retrospective study evaluated the medical records of patients who underwent salvage procedure with intra-arterial urokinase infusion after reconstruction with free flap transfer between January 2013 and July 2019. Thrombolysis with urokinase infusion was administered as salvage treatment for patients who experienced flap compromise more than 24 hours after free flap surgery. Because of an external venous drainage through the resected vein, 100,000 IU of urokinase was infused into the arterial pedicle only into the flap circulation. A total of 16 patients was included in the present study. The mean time to re-exploration was 45.4 hours (range: 24-88 hours), and the mean quantity of infused urokinase was 69,688 IU (range: 30,000-100,000 IU). 5 cases presented with both arterial and venous thrombosis, while 10 cases had only venous thrombosis and 1 case had only arterial thrombosis; in a study of 16 patients undergoing flap surgery, 11 flaps were found to have survived completely, while 2 flaps experienced transient partial necrosis and 3 were lost despite salvage efforts. In other word, 81.3% (13 of 16) of flaps survived. Systemic complications, including gastrointestinal bleeding, hematemesis, and hemorrhagic stroke, were not observed. The free flap can be effectively and safely salvaged without systemic hemorrhagic complications using high-dose intra-arterial urokinase infusion within a short period of time without systemic circulation, even in delayed salvage cases. Urokinase infusion results in successful salvage and low rate of fat necrosis.

Fig 1. Urokinase infused into an arterial pedicle of flap.

Fig 2. A 60-year-old male patient who underwent wide resection of a malignant melanoma in the left heel area and reconstruction with a free anterolateral thigh flap.

A. Clinical photograph immediately after surgery showing a good flap that progressed to congestion over time. B. Both pedicle artery and vein were thrombosed 65 hours after the surgery. After 100,000 IU of urokinase were infused, vigorous venous drainage was observed. C. Photograph immediately after flap salvage procedure. D. Clinical photograph 3 months postoperatively without further secondary procedures.

Fig 3. A 57-year-old female patient who underwent debridement of a radiation ulcer in her left foot insole area and reconstruction with a free anterolateral thigh flap.

A. Clinical photograph immediately after surgery showing a good flap that progressed to congestion over time. B. The vein was clotted with thrombi 48 hours after the surgery. After 75,000 IU of urokinase were infused, vigorous venous drainage was observed. C. Photograph immediately after flap salvage procedure. D. The surviving flap was well-maintained 18 months postoperatively.