Risk factors for postdischarge venous thromboembolism among bariatric surgery patients and the evolving approach to extended thromboprophylaxis with enoxaparin

Background: Venous thromboembolism (VTE) is one of the most common causes of postoperative mortality following bariatric surgery. The majority of VTE events occur after discharge from the hospital. Little consensus exists regarding who should receive extended enoxaparin thromboprophylaxis or how they should be dosed, namely whether to use weight-based or BMI-stratified dosing strategies. Objectives: Provide an overview of the risk factors associated with VTE in procedures among bariatric patients including the use of predictive tools to stratify risk and the various approaches to enoxaparin chemoprophylaxis in obesity. Setting: Multiple centers. Methods: A review of the literature identified studies evaluating risk factors for VTE including demographic characteristics, co-morbidities, and operative factors. The use of calculators to stratify patients by risk and approaches to extended thromboprophylaxis in obesity were evaluated as well. Results: VTE was associated with increased age, weight, male sex, and prior history of VTE, all frequently included in risk calculators. Outside of those major risk factors, there is little consensus about the importance of patient diagnoses. Weight-based dosing was often superior to standardized dosing in studies across disciplines in generating target anti-Xa levels however there is no consistent association of reduced risk of VTE with therapeutic anti-Xa levels. Conclusions: Risk calculators may be a valuable tool for identifying patients at high-risk for VTE, but their efficacy depends on the rating algorithm and inclusion of various risk factors and is methodologically limited by prophylactic interventions. Future work should consider if biochemical factors should be included in patient stratification approaches in particular when defining the ideal chemoprophylaxis approach. Transparency and consistency in data collection and reporting is needed to better assess and inform the ideal dosing strategy to prevent VTE following bariatric surgery. (C) 2021 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.