2025 Southeastern Residency Conference

Title: Rivaroxaban vs enoxaparin in post-operative bariatric patients for thromboprophylaxis


Authors: Tulsiben Patel; Jessica Sterchi; Erika McDonald; Elizabeth Egawa; Stephanie Grimes; Crystal Laudermilk; Kellie Gaby; James Ray


Objective: The purpose of this study is to compare the safety and efficacy of rivaroxaban to weight-based enoxaparin for thromboprophylaxis in post-operative bariatric patients at Blount Memorial Hospital (BMH).


Background: 
Venous thromboembolism (VTE) is linked to considerable morbidity and mortality following bariatric surgery, with over 70% of cases occurring within the first 30 days post-discharge.¹ Patients undergoing bariatric surgery are regarded as being at least at moderate risk for VTE due to severe obesity, associated comorbidities, laparoscopic surgery, and reduced mobility during the perioperative period.² Currently, low molecular weight heparin i.e. enoxaparin is the preferred pharmacologic agent for VTE prevention in non-orthopedic surgical patients. Oral agents such as warfarin, aspirin, dabigatran and factor Xa inhibitors (apixaban, rivaroxaban) have not been largely studied in non-orthopedic surgical patients. Kroll et al. compared the effectiveness of rivaroxaban 10 mg daily for 7 vs 28 days in postoperative thromboprophylaxis after bariatric surgery.³ More adverse bleeding events were seen in the 28-day group with no difference in thrombotic events between groups within the first month in this study. 
Historically, Blount Memorial Physicians Group (BMPG) surgeons prescribed weight-based enoxaparin for 14 days based on the BMI for thromboprophylaxis after a bariatric surgery. 

• BMI 30-39 kg/m2 - 30 mg q12h or 40 mg daily or 0.5 mg/kg q12h or daily
• BMI ≥40 kg/m2 - 30 mg q12h or 40 mg q12h or 0.5 mg/kg q12h or daily
• High VTE-risk bariatric surgery with BMI ≤50 kg/m2 - 40 mg q12h
• BMI ≥50 kg/m2 - 60 mg q12h 

Recently, our BMPG bariatric group has also adopted the use of rivaroxaban 10 mg daily for 7 days as a thromboprophylaxis option due to the ease of administration and fixed dosing regimens. The purpose of this study is to compare the safety and efficacy of rivaroxaban to weight-based enoxaparin for thromboprophylaxis in post-operative bariatric patients at Blount Memorial Hospital (BMH).


Methods:
This is an IRB-approved, retrospective cohort analysis to determine safety and efficacy differences between rivaroxaban and weight-based enoxaparin as thromboprophylaxis post bariatric surgery. Electronic Health Record (EHR) reports have been generated to identify the bariatric patients being discharged on either enoxaparin or rivaroxaban after the surgery. NextGen EHR has been utilized to assess for any thrombotic or bleeding events at the post-op follow up visits. The primary objective is to compare major thrombotic events with rivaroxaban versus weight-based enoxaparin at 14 days or 28 days. The secondary objectives are to compare major and minor bleeding events and minor thrombotic events with rivaroxaban versus weight-based enoxaparin at 14 days or 28 days.


Results:
Of the 170 patients screened, 80 patients in enoxaparin group and 56 patients in rivaroxaban group met the inclusion criteria. Thrombotic events were not reported in either group. Major and minor bleeding events were observed in four total patients (two major and two minor bleeds) in enoxaparin group and two total patients (one major and one minor bleed) in rivaroxaban group. 


Conclusion:
In this retrospective cohort analysis, rivaroxaban was equally effective compared to enoxaparin group secondary to absence of thrombotic events. Moreover, it resulted in less bleeding events compared to enoxaparin.  


References:

1. Winegar D, Sherif B, Pate V, DeMaria EJ. Venous thromboembolism after bariatric surgery performed by Bariatric Surgery Center of Excellence Participants: analysis of the Bariatric Outcomes Longitudinal Database. Surg Obes Relat Dis. 2011;7(2):181-188. 
2. Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2)(suppl):e227S-e277S. 
3. Kröll D, Nett PC, Rommers N, et al. Efficacy and Safety of Rivaroxaban for Postoperative Thromboprophylaxis in Patients After Bariatric Surgery: A Randomized Clinical Trial. JAMA Netw Open. 2023;6(5):e2315241.