Low-molecular-weight heparin dosing and anti-xa level monitoring in critically ill COVID-19 adults

ABSTRACT

INTRODUCTION: Coronavirus disease-19 (COVID-19) is associated with a prothrombotic state and increased incidence of thromboembolic disease. Despite limited evidence, many ICUs have implemented increased prophylactic anticoagulation dosing protocols. However, anticoagulant medications increase the risk of bleeding and warrant additional monitoring. As a result, based on the Thromboembolism and Anticoagulant Therapy During the COVID-19 Pandemic Interim Clinical Guidance from the Anticoagulation Forum, the study site increased doses of venous thromboembolism prophylaxis (VTEP) to a standard dose of enoxaparin 40 mg subcutaneous (subcut) Q12H for critically ill patients with COVID-19. For patients less than 60 kg, the dose was decreased to enoxaparin 30 mg subcut Q12H. Additionally, anti-Xa level monitoring was utilized to enhance monitoring for patients receiving enoxaparin. METHODS: This retrospective, observational study aimed to describe the anti-Xa level findings and enoxaparin dose adjustment needs. Patients with an estimated creatine clearance of less than 30 mL/min were excluded. Data collection included weight, serum creatinine, enoxaparin dose, anti-Xa levels, peak D-dimer, incidence of pulmonary emboli (PE), deep vein thrombosis (DVT), major bleeding, and minor bleeding, and ICU length of stay (LOS), hospital LOS, and mortality. Data below are presented as median (IQR). RESULTS: Seventeen adults were in the included and 76.5% (n=13) were started on enoxaparin 40 mg subcut Q12H. Twenty-three anti-Xa levels drawn at steady state. Of those, 82.6% (n=19) were within goal range, 8.7% (n=2) were below goal range, and 8.7% (n=2) were above goal range. Peak D-dimer was 2594 ng/mL (1575.5, 13086.3), two patients (10%) had a DVT, and no PEs were detected. Neither of the patients were receiving enoxaparin for VTEP at the time of the DVT. One patient (5%) had minor bleeding and no major bleeding was observed. The ICU LOS was 7 days (5, 15). Prior to the implementation of increased enoxaparin dosing, 4 anti-Xa levels were drawn for 4 patients on enoxaparin 40 mg subcut Q24H and 3 (75%) were below goal range. CONCLUSIONS: In conclusion, when utilizing increased doses of enoxaparin for VTEP, the majority of anti-Xa levels were within goal range and only 1 patient experienced minor bleeding.