PREVENTion of Clot in Orthopaedic Trauma

In this study the efficacy of Low Molecular Weight Heparin (LMWH) (Enoxaparin) compared to
Aspirin in the use of preventing death and clinically important blood clots in the lungs in
patients who sustain trauma will be investigated. The following comparisons between aspirin
and the LMWH are described in the specific aims below:

Specific Aim 1: Assess the proportion of patients who sustain death, clinically significant
pulmonary embolism, or complication after orthopaedic trauma treated with injectable LMWH
compared to those treated with aspirin.

Hypothesis 1a: The mortality rate will be non-inferior in the aspirin group Hypothesis 1b:
The rate of clinically significant PE will be non-inferior in the aspirin group Hypothesis
1c: The rate of complications will be superior (i.e., lower) in the aspirin group Specific
Aim 2: Assess satisfaction with care in orthopaedic trauma patients treated with injectable
LMWH compared to those treated with aspirin Hypothesis2a : Satisfaction will be superior in
the aspirin group Specific Aim 3: Document out of pocket patient costs in orthopaedic trauma
patients treated with injectable LMWH compared to those treated with aspirin Hypothesis3a :
Out of pocket costs will be lower in the aspirin group Specific Aim 4: Examine the proportion
of minor clot events that are less important to patients (clots in the proximal legs,
incidental PE) in orthopaedic trauma patients treated with injectable LMWH compared to those
treated with aspirin.

Hypothesis4a : The rate will be non-inferior in the aspirin group Specific Aim 5: Examine the
proportion of minor clot events that are less important to patients (clots in the proximal
legs, incidental PE) in orthopaedic trauma patients treated with injectable LMWH compared to
those treated with aspirin.

Hypothesis 5a: The rate will be non-inferior in the aspirin group.

Inclusion Criteria:

- Trauma patients who are at increased risk of blood clots from their orthopaedic
traumatic injury (operatively treated extremity injuries and all pelvis or acetabulum
fractures that are treated either operatively or non operatively) and for whom a
prophylactic blood thinner regimen would be standard of care at their institution.

- 18 years or older

Exclusion Criteria:

- Patients who present to the hospital more than 48 hours post injury

- Patients who received more than 2 doses of LMWH or Aspirin for initial prophylaxis

- Patients on long term blood thinners (other than low-dose aspirin or platelet
inhibitors such as Plavix or Aggrenox)

- Patients who have had a VTE within the last 6 months

- Patients on therapeutic (as opposed to prophylactic) blood thinners for an acute issue
at the time of admission

- Patients who have a newly diagnosed indication for therapeutic blood thinners (for
example vascular injury) that will require therapeutic anticoagulation for more than
one week

- Patients who cannot receive either of the study medications due to an allergy (history
of heparin induced thrombocytopenia, allergy to aspirin, or NSAIDs) or other medical
contraindication to blood thinners

- Patients who are on higher dose aspirin (>81 mg once a day or higher) for medical
reasons or who will be treated with higher dose aspirin

- Patients with underlying chronic clotting disorders (i.e. Factor V Leiden,
hyperhomocysteinemia, Protein C and S deficiency) that require full dose
anticoagulation or are a contraindication to venous thromboembolism chemoprophylaxis

- Patients with end stage renal disease or impaired creatinine clearance <30 ml/min at
time of randomization(note: creatinine clearance does not need to be documented if
prescribing physician would order medication without test as SOC)

- Pregnant or lactating patients

- Patients contraindicated for any reason for either medicine

- Prisoners

- Patients who do not speak either English or Spanish

- Patients may be excluded for other reasons at the discretion of the treating
physician; the reason for exclusion must be documented on the screening form.