Safety Evaluation of Weight-Tiered,Anti-Xa-Guided Versus Fixed-Dose Enoxaparin Prophylaxis in Traumatic IntraCranial Hemorrhage (SAFE-ICH): A Retrospective Cohort Study

Abstract

Background:

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.

Objective:

The purpose of this study was to evaluate the progression of tICH in trauma patients on fixed-dose (FD) versus weight-tiered, anti-Xa-guided enoxaparin for VTE prophylaxis.

Methods:

This single-center, retrospective study included adult patients admitted to an academic, level 1 trauma center between January 2013 and October 2022. Inclusion criteria were acute tICH and ≥1 prophylactic enoxaparin dose given within 7 days of admission. Groups were FD enoxaparin 30 mg every 12 hours versus weight-tiered, anti-Xa dose-adjusted (DA) enoxaparin per institutional protocols. The primary endpoint was tICH expansion, defined as new or enlarging tICH on computed tomography (CT) or need for neurologic operative intervention within 14 days from chemoprophylaxis initiation. The secondary endpoint compared VTE incidence. A multivariate logistic regression identified risk factors for tICH expansion.

Results:

A total of 595 patients were included (119 FD; 476 DA). Baseline characteristics were well-matched between groups, including time from stable head CT to chemoprophylaxis initiation. The FD cohort received a lower weight-based dose compared with the DA cohort (0.40 [0.33-0.47] mg/kg/dose vs 0.45 [0.37-0.53] mg/kg/dose, P = 0.001). Traumatic ICH expansion was significantly higher in the FD cohort compared with DA (5 [4.2%] vs 5 [1.1%], P = 0.017). There were similar rates of VTE (2.5% vs 3.6%, P = 0.57) between groups. No independent risk factors were identified for progression of tICH, but higher body mass index was associated with reduced risk.

Conclusion and relevance:

Higher initial enoxaparin doses and anti-Xa-driven adjustment were not associated with greater rates of tICH expansion in this study, albeit an overall low incidence. These findings highlight the multifactorial nature of TBI and tICH expansion.