The impact of surgical complications as a main risk factor for venous thromboembolism: a multicenter study

Studies suggest that postoperative complications are a risk factor for venous thromboembolism (VTE) after bariatric surgery. Knowledge of factors associated with a higher risk of VTE after bariatric surgery may be essential to select patients who may benefit from either prolonged or intensified thrombosis prophylaxis. The aim of this study is to determine the relationship between postoperative complications and VTE after bariatric surgery and other classical risk factors.

A retrospective multicenter case-control study was performed in patients who had bariatric surgery between January 2008 and September 2011. VTE until 6 months after surgery was registered, and patients were contacted to ascertain the results. For every case of VTE after surgery, 6 control patients were selected who were matched for gender, age, participating center and type of surgery. Risk factors for VTE before and after surgery and postoperative complications were registered.

A total of 2,064 surgeries were included. In 12 patients, VTE occurred within 6 months after bariatric surgery (incidence 0.58 %, 95 % confidence interval (CI) = 0.25-0.93). There was a strong association of complications after surgery (cases 91.7 %, controls 15.3 %, odds ratio (OR) 61.0; 95 % CI = 7.1-521.3) or intensive care admission (cases 50.0 %, controls 11.1 %, OR = 8.0; 95 % CI = 2.1-30.8) with VTE. The majority of postoperative complications were anastomotic leak, abdominal abscess, and infection. We could not detect an association between classical thrombosis risk factors and postoperative VTE.

The incidence of VTE is low after bariatric surgery using thrombosis prophylaxis. However, there is a strong association between postoperative complications and VTE. These patients may benefit from more intensive thrombosis prophylaxis.