(1562) Dose-Adjusted Versus Fixed-Dose Enoxaparin Prophylaxis in Traumatic Intracranial Hemorrhage

Introduction: Traumatic intracranial hemorrhage (tICH) increases venous thromboembolism (VTE) risk counterbalanced by a life-threatening bleed in a critical organ space. Weight-tiered and anti-Xa guided enoxaparin dosing may reduce VTE incidence, but current literature is limited regarding safety in patients with tICH. The purpose of this study was to evaluate the safety and efficacy of weight-tiered, anti-Xa guided versus fixed dosing enoxaparin in trauma patients with ICH.

Methods: This was a single-center, retrospective study of patients admitted to an academic, quaternary, level 1 trauma center between January 2013 and October 2022. Inclusion criteria were adults with acute tICH who received ≥1 enoxaparin dose within 7 days of admission. Study groups were defined as patients who received VTE prophylaxis per institutional team-based protocols for standard of care, fixed dose (FD) of enoxaparin 30 mg every 12 hours versus weight-tiered, anti-Xa dose adjusted (DA) enoxaparin. Matching was performed in a 1:4 fashion based on age within 5 years and head abbreviated injury score. The primary endpoint was expansion of tICH defined as new or enlarging tICH on computed tomography (CT) or need for neurologic operative intervention within 14 days from chemoprophylaxis initiation. Secondary endpoints included VTE incidence. A multivariate logistic regression was performed to identify risk factors for tICH expansion.

Results: A total of 595 (119 FD; 476 DA) patients were included. Baseline characteristics were well-matched between groups including both time from admission and stable head CT to chemoprophylaxis initiation. The tICH expansion incidence was significantly higher in the FD cohort (5 [4.2%] vs 5 [1.1%], p=0.017). VTE, DVT, and PE incidences were similar between groups. No independent risk factors were identified for progression of tICH, but higher BMI reduced the risk of tICH expansion.

Conclusions: Weight-tiered, anti-Xa dose-adjusted enoxaparin reduced the incidence of tICH expansion compared to fixed dosing. High body weight may reduce the risk of tICH expansion regardless of dosing strategy, but multicenter studies are needed.