Each Missed Dose of Thromboprophylaxis in Trauma Patients Significantly Increases the Risk of VTE

Thromboembolism Prevention in Surgical Patients

The increased risk of VTE in patients after trauma or surgery is due to a combination of factors – venous stasis, endothelial injury, disrupted fibrinolysis, and reduced levels of serum anticoagulant factors. Even with standard prophylaxis, the incidence of pulmonary embolism after trauma ranges from 2% to 22%, making it the 3rd leading cause of death in patients who survive the first 24 hours after severe trauma. Deep vein thrombosis (DVT) without prophylaxis is estimated to occur in up to 60% of trauma patients.

Low molecular weight heparins (LMWH) are the most commonly used agents in standard thromboprophylaxis. The efficacy and safety of enoxaparin sodium in preventing DVT have been confirmed by numerous clinical studies and long-term follow-up. However, temporary discontinuation of enoxaparin during hospitalization is relatively common. Thromboprophylaxis is typically paused before planned surgery, and sometimes treatment is refused by the patient or due to medical staff errors.

Risk of Interrupting Thromboprophylaxis

Deep Vein Thrombosis More Common in Patients with Missed Enoxaparin Doses

A prospective American analysis, which included 202 patients from the surgical department of a university hospital in Oregon following trauma or major surgery, found that DVT occurred in 4.8% of patients despite full adherence to enoxaparin prophylaxis. In the group of patients with at least one missed dose of enoxaparin, the incidence of DVT reached 23.5%. The only independent risk factors for DVT in this prospective analysis were age over 50 and interruption of enoxaparin prophylaxis.

The authors concluded that while thromboprophylaxis should not continue in patients undergoing high-risk procedures such as intracranial or spinal surgeries, the decision to stop prophylaxis for low-risk surgeries should be carefully evaluated by weighing the risk of bleeding against the risk of DVT in each patient. Missed doses due to medical staff errors or patient refusal should be completely eliminated through continuous education.

Missed Enoxaparin Doses More Often Observed in Patients with VTE

Similar results were found in a recently published study by a team from Corewell Health West Hospital in Grand Rapids, Michigan. The retrospective cohort study included trauma patients hospitalized between January 2012 and January 2021 in a tertiary trauma center who received prophylactic enoxaparin. Patients who developed VTE were matched based on propensity score (with 10 variables) with those who did not develop VTE. The entry criteria were met by 493 individuals, and after matching, the final cohort included 184 patients.

The proportion of patients who missed at least one dose of thromboprophylaxis was significantly higher in the VTE group than in the non-VTE group (34.8% vs. 21.7%; p = 0.049). The results were consistent when evaluating the number of missed doses (p = 0.038) and the number of consecutive missed doses (p = 0.035).

Most missed prophylactic doses of enoxaparin were due to planned surgery, not bleeding complications.

Conclusion

Missing doses of enoxaparin in trauma patients significantly increases the risk of VTE. Therefore, the surgical team should carefully assess the risk of bleeding complications associated with thromboprophylaxis versus the risk of thromboembolic events when considering discontinuing treatment before surgery.

Sources:

1. Spradling J., Garfinkel S., Edgecomb T. et al. Venous thromboembolism rates in trauma patients significantly increase with missed prophylactic enoxaparin doses. Am Surg 2024 Sep; 90 (9): 2265–2272, doi: 10.1177/00031348241269401.
2. Louis S. G., Sato M., Geraci T. et al. Correlation of missed doses of enoxaparin with increased incidence of deep vein thrombosis in trauma and general surgery patients. JAMA Surg 2014; 149 (4): 365–370, doi: 10.1001/jamasurg.2013.3963.