Comparing Enoxaparin to Fondaparinux to Prevent Venous Thromboembolism (VTE) in Bariatric Surgical Patients

Study Overview
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Brief Summary
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This pilot study is designed to determine the feasibility of conducting a randomized clinical trial comparing fondaparinux sodium (Arixtra) once daily with enoxaparin (Lovenox®) twice daily with respect to preventing deep vein thrombosis (DVT) and pulmonary embolism (PE) after bariatric surgery in obese patients.

Detailed Description
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In order to determine the feasibility of such a trial we need to determine the necessary sample size. In order to determine the necessary sample size, we need to obtain estimates of the incidence of DVT and the prevalence of PE using MRV in each treatment group. Descriptive statistics and 95% confidence intervals will be calculated to determine the incidence of DVT and the prevalence of PE using MRV in obese patients who have received treatment to prevent DVT and PE associated with bariatric surgery. Anti-factor Xa levels will be used to help determine if treatments are reaching appropriate levels.

Official Title
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A Pilot Study to Determine the Feasibility of Conducting a Randomized Clinical Trial Comparing Fondaparinux Sodium (Arixtra) Once Daily With Enoxaparin (Lovenox®) Twice Daily With Respect to Preventing VTE After Bariatric Surgery in Obese Patients

Conditions
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Deep Venous Thrombosis, Pulmonary Embolism

Intervention / Treatment
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* Drug: Enoxaparin
* Drug: Fondaparinux


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men or women 18 years or older. Body mass index (BMI) of 35kg/m2 or greater. Undergoing laparoscopic bariatric surgery, i.e., laparoscopic sleeve gastrectomy, laparoscopic Roux-en Y gastric bypass or laparoscopic duodenal switch. Exclusion Criteria: History of previous deep vein thrombosis. History of previous pulmonary emboli. History of documented clotting/coagulation disorder. History of cancer. Weight < 50 kg or > 200 kg or unable to fit in MRI scanner. Presence of metallic foreign bodies Recent history of smoking (within the last year). History of venous stasis disease. History of obesity hypoventilation syndrome. Patients who are unable to lay flat for extended periods of time or are claustrophobic. Patients who have a pacemaker, an implanted defibrillator or certain other implanted or electronic or metallic devices (implanted medical or metallic devices, shrapnel, or metal). History of hypersensitivity reaction to anticoagulation products. History of HIT (Heparin Induced Thrombocytopenia. History of Renal Insufficiency (Creatinine Clearance < 50). Active clinically significant bleeding. Acute bacterial endocarditis. BMI > 60. Patients with metallic foreign body or implant (unable to have an MRV study).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Enoxaparin<br>Patients will receive enoxaparin 40mg subcutaneously twice daily during perioperative period of bariatric surgery. Patients will be encouraged to ambulate and compression stockings while in bed. | Drug: Enoxaparin<br>* Patients will receive enoxaparin 40mg subcutaneously twice daily during perioperative period of bariatric surgery. Patients will be encouraged to ambulate and compression stockings while in bed.<br>|
| Active Comparator: Fondaparinux<br>Fondaparinux 5mg subcutaneously 6 hours following surgery, fondaparinux 5mg subcutaneously once daily during hospitalization. Patients will be encouraged to ambulate and compression stockings while in bed. | Drug: Fondaparinux<br>* Fondaparinux 5mg subcutaneously 6 hours following surgery, fondaparinux 5mg subcutaneously once daily during hospitalization. Patients will be encouraged to ambulate and compression stockings while in bed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To estimate the prevalence of asymptomatic deep venous thrombosis and pulmonary emboli in obese patients undergoing bariatric surgery. |  | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess the relationship of Anti-factor Xa levels and the occurrence of deep venous thrombosis and pulmonary emboli in bariatric patients receiving standard dose of anticoagulation (enoxaparin/Lovenox or fondaparinux/Arixtra). |  | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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DVT, PE, MRV, bariatric surgery