VTE occurrence lowered by adjusting thromboprophylaxis dosages to individual anti-Xa levels

February 2020 Prevention Marjolein Groot

Researchers dr. Kramme and collagues expected a relationship between administered doses of enoxaparin thromboprophylaxis and a high occurrence of subprophylactic anti-factor Xa (anti-Xa) levels, from previous research. The researchers investigated the efficacy and safety of administering enoxaparin in doses adjusted to individual anti-Xa levels of patients with a higher risk to develop venous thromboembolism (VTE).

In the study, 197 patients were included. Of this group, 133 patients were in the control group and they received the standard dosage of thromboprophylaxis. The 64 patients in the experimental group received the enoxaparin in a dosage based on their individual anti-Xa levels, to reach the desired anti-Xa level of >0,20 IU/mL. All patients received the thromboprophylaxis when they underwent abdominal carcinoma surgery.

Adjusting dosages lowers VTE

In the intervention group, 50/64 patients (78.1%) had subprophylactic peak anti-Xa levels before receiving the thromboprophylaxis. Of the patient intervention group, 0% developed VTE. Of the patients who received standard dosages, 8.27% developed VTE (p=0.018). Furthermore, there was no difference in the occurrence of major bleeding (3.12% with adjusted dosages, 1.50% with standard dosages [p=0.597], the frequency of packages red blood cell transfusions (17.2% vs 23.3%, p=0.426) nor in the mean Hb-levels when departing the hospital (9.58 vs 9.36 g/dL, p=0.414).

Safe reductions

From these results, the researchers conclude that adjusting the doses of enoxaparin thromboprophylaxis to the individual anti-Xa levels causes the incidence of VTE to be lowered, without increasing chances on major bleedings.


Kramme K, Sarraf P & Munene G. (2019). Prophylactic Enoxaparin Adjusted by Anti-Factor Xa Peak Levels Compared with Recommended Thromboprophylaxis and Rates of Clinically Evident Venous Thromboembolism in Surgical Oncology Patients. Journal of the American College of Surgeons.