Low Early Antifactor Xa Target Achievement Rate of Low-Molecular-Weight Heparin for Treating Venous Thromboembolism in Patients in Intensive Care.

Abstract

This study aimed to evaluate whether early antifactor Xa (anti-Xa) achieved the target range when venous thromboembolism (VTE) was treated with low-molecular-weight heparin (LMWH), based on body weight and renal function in patients treated in intensive care units (ICUs). Anti-Xa levels in patients treated with LMWH for VTE in ICU and medical wards between January 1,2021, and June 30,2022, were retrospectively assessed. The demographics, laboratory parameters, and early anti-Xa peak levels of patients were collected. All patients were followed up for 3months to collect VTE recurrence/bleeding events. Univariate and multivariate linear regression analyses were used to identify the factors affecting anti-Xa levels. A total of 108 patients were enrolled in this study, including 70 patients in ICU and 38 patients on medical wards. The early anti-Xa level (0.36 vs 0.61IU/mL, P<.001) and target achievement rate (21.4% vs 39.5%, P=.015) of patients in ICU were lower than those in medical wards. Multivariate linear regression showed that only antithrombin (AT) significantly affected anti-Xa levels in patients in ICU (β=0.008, 95%CI 0.005 to 0.011, P<.001). There was no significant difference in VTE recurrence events (11.8% vs 7.5%, P=.628) and bleeding events (29.4% vs 17.0%, P=.304) between the early anti-Xa within-target group and the early anti-Xa below-target group. Low anti-Xa peak levels are common in patients in ICU. AT activity should be monitored when using LMWH in critically ill patients.