Portal venous system thrombosis can develop after bariatric surgery. A systematic review and meta-analysis was conducted to evaluate the incidence of portal venous system thrombosis after bariatric surgery and clarify the role of anticoagulation for the prevention of portal venous system thrombosis after bariatric surgery.
PubMed, EMBASE, and Cochrane Library databases were searched. The incidence of portal venous system thrombosis after bariatric surgery was pooled by a random-effect model. Subgroup analyses were performed to explore the incidence of portal venous system thrombosis according to the average duration of prophylactic anticoagulation (extended versus short-term). Meta-regression and sensitivity analyses were performed to explore the source of heterogeneity.
Among 2,714 papers initially screened, 68 studies were included. Among 100,964 patients undergoing bariatric surgery, 300 developed portal venous system thrombosis. The pooled overall incidence of portal venous system thrombosis after bariatric surgery was 0.419% (95% confidence interval: 0.341%-0.505%). The pooled incidence of portal venous system thrombosis after bariatric surgery was numerically lower in patients who received extended prophylactic anticoagulation protocol after bariatric surgery than those who received short-term prophylactic anticoagulation protocol (0.184% vs 0.459%). Meta-regression analyses demonstrated that sample size (P = .006), type of surgery (P < .001), and average duration of prophylactic anticoagulation (P = .024) might be sources of heterogeneity, but not region, publication year, history of bariatric surgery, follow-up duration, or use of prophylactic anticoagulation. Sensitivity analyses could not identify any source of heterogeneity. The estimated mortality of portal venous system thrombosis after bariatric surgery was 1.33%.
Portal venous system thrombosis after bariatric surgery is rare, but potentially lethal. Extended prophylactic anticoagulation protocol may be considered in patients at a high risk of developing portal venous system thrombosis after bariatric surgery.

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