Background

Venous thromboembolism (VTE) is a leading cause of 30-day mortality after metabolic and bariatric surgery (MBS). Multiple predictive tools exist for VTE risk assessment and extended VTE chemoprophylaxis determination. This study’s objective was to review existing risk stratification tools and compare their predictive abilities.

Methods

Retrospective analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database was performed (2015-2019) for all primary laparoscopic MBS cases. VTE clinical factors and risk assessment tools were evaluated: body mass index (BMI) threshold of 50 kg/m2, Caprini risk assessment model (RAM), and three bariatric-specific tools. MBS patients were deemed high-risk based on criteria from each tool and further assessed for sensitivity, specificity, and positive predictive value.

Results

Overall, 709,304 patients were identified with a 0.37% VTE rate. Bariatric-specific tools included multiple predictors: procedure, age, race, gender, operative time, length of stay, heart failure, and dyspnea at rest; operative time was the only variable common to all three. The BMI cut-off and Caprini RAM had higher sensitivity but lower specificity when compared to 2 bariatric models while bariatric tools had a wider sensitivity range compared to specificity with overall low sensitivity (summarized in Table 1). The bariatric-specific tools would have recommended extended prophylaxis for 1.1%-15.6% of patients.

Conclusions

Existing MBS VTE risk assessment tools differ widely for inclusion variables, ‘high-risk’ definition, and predictive performance. Further research is needed to determine the optimal risk-stratified approach for predicting VTE events and determining the need for extended prophylaxis.