Background

Balancing the risk of venous thromboembolism and post-operative bleeding is an ongoing challenge in the bariatric surgery population, and current chemoprophylaxis recommendations are inconsistent. Enoxaparin dosing at 30mg Q12 hours was thought to be inadequate for prophylaxis in patients with obesity and an increase to 40mg was recommended by our pharmacy department. A perceived increase in post-operative bleeding prompted the following retrospective investigation. A control group (30mg enoxaparin twice daily) was compared to an intervention group (40mg enoxaparin twice daily) over consecutive three-month intervals for patients undergoing laparoscopic Roux-en-Y gastric bypass (RYGB), laparoscopic vertical sleeve gastrectomy (LVSG), conversion from LVSG to RYGB, and gastric band removal. Demographics and rates of VTE and bleeding complications were recorded. 162 total patients were included, 84 in the control group and 78 in the intervention group. The study populations were comparable regarding age, gender, BMI, procedures performed, and overall size. There were no VTE events in either group. Despite 3 patients in the intervention group experiencing post-operative bleeding (3.8%), and none in the control group, this did not reach statistical significance [p = 0.11]. Notably, 2 of these 3 patients received only 30mg enoxaparin in pre-op, and had subsequent doses held due to concern for postoperative bleeding risk. 40mg enoxaparin twice daily did not increase post-operative bleeding risk in our study, however further research is needed to further determine optimal dosing and duration. Perhaps a stronger predictor of post-operative bleeding is intraoperative blood loss.