Venous Thromboembolic Prophylaxis After Trauma: Three Times a Day Unfractionated Heparin Versus Twice a Day Enoxaparin

The rate of venous thromboembolic events in trauma patients at high risk for deep vein thrombosis and pulmonary embolism receiving low dose unfractionated heparin every 8 hours will be equivalent or less than a similar group of patients given a standard every 12 hour dose of low molecular weight heparin.

Venous thromboembolism (VTE) is a common and potentially life threatening complication of major trauma. The risk of developing deep vein thrombosis (DVT) following major trauma exceeds 50% unless adequate chemoprophylaxis is used. Recent national quality improvement initiatives, such as the Surgical Care Improvement Project (SCIP), mandate the risk stratification of hospitalized patients and the use of VTE prophylaxis based on the risk assessment. Low Molecular Weight Heparin (LMWH, enoxaparin) and Low Dose Unfractionated Heparin (LDUH) are commonly used alternatives for VTE chemoprophylaxis following major trauma. LMWH became favored in most trauma centers following a prospective randomized controlled trial comparing the two agents that demonstrated superior efficacy and equivalent safety of LMWH over a twice per day dosing of LDUH. The results of this study were largely responsible for practice guideline recommendation changes favoring the use of LMWH in trauma patients by both the American College of Chest Physicians (ACCP) and the Eastern Association for the Surgery of Trauma (EAST). , This landmark paper did not, however, utilize a three times a day (every 8 hours) dosing of LDUH for prophylaxis, which is the dosing schedule recommended by earlier trials. LDUH administered every 8 hours was demonstrated to have similar efficacy to LMWH in trauma patients in a recent retrospective study. These results call into question the validity of the conclusions of the 1996 study. Because LDUH is less expensive ($0.50/dose) than LMWH (Enoxaparin, $28/dose), similar effectiveness would imply a significant reduction in the cost of prophylaxis and increased value to patients, providers and accountable care organizations and tax-payers.

To validate this hypothesis the investigators propose to achieve the following study objectives:

1. Assess the degree of risk for VTE in each patient admitted to the trauma service
2. Determine the rate of VTE events in high risk trauma patients receiving either:

   * LMWH (30mg enoxaparin) given every twelve hours
   * LDUH (5000 Units unfractionated Heparin) given every eight hours.
3. Identify and quantify any adverse events associated with either treatment arm.
4. Compare the value of LMWH versus LDUH in the prophylactic treatment of VTE disease in trauma patients.

Eligibility Criteria:
Inclusion Criteria:

* Admitted to Scripps Mercy Trauma Service
* ≥18 Years old
* Stratified to either Significant or Highest risk of VTE by ACCP guidelines

Exclusion Criteria:

* Estimated Injury Severity Score (ISS) ≤9
* Likely to be discharged before hospital day 7
* Systemic coagulopathy defined with an International Normalized Ratio (INR) of ≥1.2
* Body Mass Index (BMI) \>40
* Likely to Survive for \<7 Days
* Pregnancy
* Evidence of renal insufficiency (Cr ≥1.3)
* Delayed transfer to this facility (\>24 hrs)
* Prisoners