(0756) Venous Thromboembolism Prophylaxis After Free Flap Reconstruction of Head and Neck Cancer Defects

Introduction: Venous thromboembolism (VTE) is a serious potential complication for individuals undergoing major surgery. Currently, there are no guidelines outlining the optimal VTE chemoprophylaxis regimen for head and neck cancer surgical patients. This study aims to compare the incidence of VTE and bleeding complications in individuals who received either subcutaneous (SC) low molecular weight heparin or SC enoxaparin after undergoing head and neck cancer surgery.

Methods: A retrospective cohort study of patients who underwent head and neck cancer resection with free flap reconstruction at UF Health Shands Hospital between Jan 1, 2014 to Dec 31, 2023 was performed. Patients received either SC heparin or SC enoxaparin postoperatively as VTE chemoprophylaxis. Rates of VTE and flap failure were recorded up to 90 days postoperatively. Length of hospital stay, rates of arterial insufficiency, venous congestion, and bleeding complications (hematoma or hemorrhage) up to 24 hours after cessation of VTE chemoprophylaxis were also recorded. Fisher's exact test for count data was performed for preliminary analysis.

Results: 235 patients met study criteria: 121 (51%) received SC heparin and 114 (49%) received SC enoxaparin. Mean age at time of surgery was 64 years old. Rates of postoperative VTE were similar between the SC enoxaparin and SC heparin groups (0.9% vs. 1.7%, P >0.9). The enoxaparin group had a slightly higher rate of bleeding complications (7.9%, P= 0.077) compared to the heparin group (2.5%). All but one patient required returning to the operating room for hematoma evacuation or control of hemorrhage. Mean length of hospital stay for the enoxaparin group was 10.2 days (SD 8.1), and 11.4 (SD8.6) for the heparin group (P= 0.4). All other measured outcomes were similar between groups.

Conclusions: In this study, SC heparin and SC enoxaparin VTE prophylaxis showed similar rates of VTE up to 90 days post-operation. SC enoxaparin had a slightly higher rate of bleeding complications, but this did not achieve statistical significance. Risk of complications should considered when choosing between VTE prophylactic medications.