LAUSR

INTRODUCTION Optimal perioperative thromboprophylaxis is crucial to avoid flap thrombosis and to achieve high rates of microsurgical success. At our institution, implementation of a risk-stratified anticoagulation (AC) protocol preliminarily showed a reduction in postoperative thrombotic events and flap loss. We present an updated analysis of surgical outcomes using risk-stratified AC in thrombophilic patients who underwent free tissue transfer (FTT) reconstruction for non-traumatic lower extremity (LE) wounds. METHODS We retrospectively reviewed patients who underwent FTT to the LE from 2012 to 2021. Our risk-stratification AC protocol was implemented in July 2015. Low-risk and moderate-risk patients received subcutaneous heparin (SQH). High-risk patients received heparin infusion titrated to a goal PTT of 50-70 seconds. Prior to July 2015, non-stratified patients were treated with either SQH or low-dose heparin infusion (500 U/hour). Patients were divided into two cohorts (non-stratified and risk-stratified) based on date of FTT reconstruction. Primary outcomes included rates of postoperative complications, flap salvage, and flap success. RESULTS Two-hundred nineteen hypercoagulable patients who underwent FTT to LE were treated with non-stratified (n=26) or risk-stratified (n=193) thromboprophylaxis. Overall flap success rate was 96.8% (n=212). Flap loss was lower among risk-stratified patients (1.6% vs. 15.4%, p=0.004), which paralleled a significant reduction in postoperative thrombotic events (2.6% vs. 15.4%, p=0.013). Flap salvage was accomplished more often in the risk-stratified cohort (80% vs. 0%, p=0.048). Intraoperative anastomotic revision (OR: 6.10; p=0.035) and non-risk stratification (OR: 9.50; p=0.006) were independently associated with flap failure. CONCLUSION Hypercoagulability can significantly impact microsurgical outcomes. Implementation of a risk-stratified AC protocol can significantly improve flap outcomes.