D27. Effect of Postoperative Anticoagulation Regimen on Lower Extremity Free Flap Outcomes

PURPOSE: Free flap reconstruction for lower extremity (LE) trauma has a higher failure rate than in other anatomic regions. Anticoagulation selection in the immediate postoperative period may influence free flap outcomes. This study evaluates complication rates associated with varying anticoagulation protocols among LE free flap reconstruction. METHODS: Patients with LE trauma with free flap reconstruction from 2016-2021 were included for retrospective chart review. Complications were divided into major (hematoma, flap thrombosis, flap necrosis >10%, infection requiring reoperation) and minor (wound dehiscence, flap necrosis <10%, infection treated with antibiotic alone) categories. Patients were categorized into 4 groups based on postoperative anticoagulation regimen (aspirin, heparin drip, aspirin + heparin drip, and DVT-prophylaxis only). Complication rates were compared between each group. Univariate analysis was performed using ANOVA and chi-squared tests. Multivariable analysis was performed with a generalized linear model to predict any major complications. P values were set at P<0.05. RESULTS: Of 199 patients, 18.6% received aspirin only, 38.2% received heparin drip only, 39.2% received aspirin + heparin drip, and 4.0% received DVT prophylaxis only. Demographics were similar between the groups. Major complication rates were negatively correlated with the aspirin group (p=0.001) and the heparin drip group (p=0.031). CONCLUSION: In patients with LE free tissue transfer after acute trauma, postoperative use of aspirin only or heparin drip only results in fewer complications than aspirin + heparin drip or DVT-prophylaxis alone.