Anti-factor Xa levels in patients undergoing laparoscopic sleeve gastrectomy: 2 different dosing regimens of enoxaparin

Background Morbidly obese patients undergoing bariatric surgery are at risk for developing venous thromboembolic events. Data regarding the appropriate dosing strategy in this special population is limited. Objective To evaluate 2 different dosing regimens of enoxaparin in a prospective cohort of patients undergoing laparoscopic sleeve gastrectomy. Setting University hospital, Israel Methods The study cohort consisted of 54 patients divided into 2 groups. Group I received 40 mg enoxaparin every 24 hours, and group II received 60 mg enoxaparin every 24 hours. Anti-factor Xa (FXa) levels from each patient were obtained 3 to 4 hours after administration of the third dose of enoxaparin. Levels between.2 and 0.5 U/mL were considered appropriate. Five additional patients were selected as controls. Results There were 31 patients in group I and 23 patients in group II. There was a statistically significant difference between anti-FXa levels achieved in each group:.247 U/mL in group I (range,.15–.39) versus.346 U/mL (range,.24–.8) in group II. Both groups achieved mean anti-FXa levels in the range designated appropriate with a high proportion of patients achieving appropriate levels (group I: 80.6%; group II: 91.3%). Univariate analyses found that total weight and sex were significantly correlated with anti-FXa levels. However, a multivariate analysis including enoxaparin dose found that only enoxaparin dose remained significantly correlated with anti-FXa levels. Conclusion In the absence of sufficient data regarding clinical efficacy and safety of different dosing regimens both dosing regimens studied are reasonable choices for venous thromboembolic events prophylaxis after bariatric surgery.