W. Johnston1, L. Perkins1, A. E. Berndtson1, T. W. Costantini1, K. Box1, L. N. Haines1 1University Of California – San Diego, Division Of Trauma, Surgical Critical Care, Burns And Acute Care Surgery, San Diego, CA, USA
Introduction: Enoxaparin is a low-molecular weight heparin that has become the standard of care for venous thromboembolism (VTE) prophylaxis. Since enoxaparin is renally excreted there are concerns for bioaccumulation and increased risk for bleeding complications when used in patients with renal insufficiency. Therefore, most consensus guidelines for VTE prophylaxis recommend subcutaneous heparin rather than enoxaparin as the chemoprophylactic agent of choice in patients with renal insufficiency. We hypothesized that using enoxaparin for VTE prophylaxis in surgical ICU patients with renal impairment is safe, with low rates of above target anti-Xa levels and bleeding complications.
Methods: A retrospective review of trauma, burn, and emergency general surgery (EGS) ICU patients admitted between 2018 and 2023 was performed. Patients were included if they were over 18 years old, admitted for at least four days, received at least three consecutive doses of enoxaparin with an appropriately timed peak serum anti-Xa level, and had renal insufficiency. Renal insufficiency was defined as serum creatinine > 1.3mg/dL or a GFR < 50 ml/min. Target peak anti-Xa levels were defined as 0.2-0.4 IU/ml for prophylactic dosing and 0.5-1.0 IU/ml for therapeutic dosing. The primary outcome was the incidence of above target anti-xa levels. Secondary outcomes included incidences of bleeding complications and VTE events.
Results: A total of 55 patients met inclusion criteria; 72.7% Trauma, 18.2% Burn, and 9.1% EGS. The population had a median age of 59 [IQR 33-66] and was 74.5% male. Enoxaparin dosing was weight-based, with 12.7% of patients receiving 30mg twice a day (BID), 72% of patients receiving 40mg BID, and 9% of patients receiving 50mg BID. Three patients were on therapeutically dosed enoxaparin and received 1mg/kg BID. The median creatinine was 1.4 [IQR: 1.31-1.8], with 16.4% of patients on hemodialysis. The majority of patients had an anti-Xa level below (39.2%) or at the target anti-Xa level (49.1%) with 12.7% above the target level. Two bleeding complications were identified; however, both patients had anti-Xa levels that were within goal range at the time of the complication. A total of 14 VTE events were recorded: 10 DVTs (18.2%) and 4 PEs (7.2%).
Conclusion: Patients with renal insufficiency who received enoxaparin had low rates of above target anti-Xa levels and bleeding complications. Overall, this data suggest that enoxaparin can be safely used in critically ill patients with renal insufficiency if anti-Xa levels are followed.
