The purpose of this study is to assess anti-factor Xa concentrations in patients given prophylactic enoxaparin after bariatric surgery.

FDA-approved enoxaparin dosing for venous thromboembolism (VTE) prophylaxis is a fixed-dose regimen irrespective of body mass index (BMI) or actual body weight (ABW). Clinical trials suggest that dosing may be inadequate for obese patients. We plan to assess anti-factor-Xa concentrations in patients who received prophylactic enoxaparin after bariatric surgery.

This prospective study will examine 150 anti-factor Xa concentrations from patients 18 years or older undergoing primary Roux-en-Y gastric bypass surgery at St. Vincent Carmel Bariatric Center of Excellence. Patients receive varying prophylactic enoxaparin regimens at the surgeon's discretion. Anti-factor-Xa concentrations are obtained at steady state.

Inclusion Criteria:

• Patients 18 years and older undergoing primary roux-en-Y gastric bypass surgery at St. Vincent Carmel Bariatric Center of Excellence

Exclusion Criteria:

• Receiving anticoagulation therapy prior to surgery (i.e. warfarin)
• Did not receive enoxaparin after surgery

Patients 18 years or older undergoing primary roux-en-Y gastric bypass surgery at St. Vincent Carmel Bariatric Center of Excellence.