Emergency Department Management of Acute Venous Thromboembolism in Patients With Obesity With Intravenous Unfractionated Heparin and Anti-Xa Monitoring.

Background: Unfractionated heparin (UFH) remains a frequently utilized agent in the emergency department (ED) for management of acute venous thromboembolism (VTE). While various protocols of UFH dosing have been proposed for patients with obesity, the optimal dosing and monitoring strategy is unclear. Objective: This study aims to compare the time to the first therapeutic anti-Xa level in obese acute VTE patients following the use of either total body weight (TBW) or adjusted body weight-based (AdjBW) dosing of UFH in the ED, and to analyze the impact of different dosing strategies on patient outcomes. Methods: Inclusion criteria included adult patients with a BMI > 30 kg/m2, and suspected VTE managed with UFH per institutional protocol utilizing a bolus dose followed by maintenance infusion and anti-Xa monitoring. The primary outcome was time to the first therapeutic anti-Xa level in the group dosed per TBW compared with the group dosed per AdjBW. Safety outcomes included incidence of bleeding events, protamine administration, and mortality. Results: There were 32 patients included in the study. Patients dosed per TBW achieved a median time to first therapeutic anti-Xa level of 14.5 hours compared with 15 hours in the AdjBW group (P = .613). The median therapeutic UFH infusion rate was 16 units/kg/hr in the TBW group compared with 13.5 units/kg/hr in the AdjBW group (P < .001). Safety outcomes were not significantly different between groups. Conclusion: Patients presenting to the ED with acute VTE may be managed with UFH using either a TBW or AdjBW dosing strategy.