Efficacy and safety of weight-adjusted heparin prophylaxis for the prevention of acute venous thromboembolism among obese patients undergoing bariatric surgery: a systematic review and meta-analysis

Thromb Res. 2014 Apr;133(4):682-7. doi: 10.1016/j.thromres.2014.01.021. Epub 2014 Jan 23.


Background: The bariatric surgical population is a particularly high risk population for VTE. It is unclear if standard (i.e. non-adjusted) thromboprophylaxis doses of low-molecular weight or unfractionated heparin provide adequate protection for obese patients undergoing bariatric surgery, or if higher doses are required. We sought to determine whether a weight based thromboprophylactic dosing regimen is safe and effective in the post-operative period for obese patients undergoing bariatric surgery.

Methods: A systematic literature search strategy was conducted using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and all EBM Reviews. Pooled proportions for the different outcomes were calculated.

Results: A total of 6 studies (1 RCT, 4 cohort studies and one quasi experimental trial) containing 1,858 patients were include in the systematic review. Post bariatric surgery patients receiving weight-adjusted prophylactic doses of heparin products, had an in hospital rate of VTE of 0.54% (95% CI: 0.2 to 1.0%) compared to 2.0% (95% CI: 0.1 to 6.4%) for those that did not weight adjust doses. Rates of major bleeding were similar for both groups: 1.6% (95% CI: 0.6 to 3.0%) for patients receiving weight-adjusted dosing compared to 2.3% (95% CI: 1.1% to 3.9%) for those receiving standard doses of heparin products.

Conclusions: Adjusting the dose of heparin products for thromboprophylaxis post-bariatric surgery seems to be associated with a lower rate of in hospital VTE compared to a strategy of not adjusting the dose, although this did not reach statistical significance. This practice does not lead to an increase in adverse major bleeding events.

Keywords: Bariatric surgery; Hemorrhage; Heparin; Low-molecular weight; Mortality; Venous thromboembolism.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Acute Disease
  • Bariatric Surgery / adverse effects
  • Bariatric Surgery / methods*
  • Cohort Studies
  • Hemorrhage / chemically induced
  • Heparin / administration & dosage*
  • Heparin / adverse effects*
  • Humans
  • Obesity / blood
  • Obesity / surgery*
  • Prevalence
  • Venous Thromboembolism / etiology
  • Venous Thromboembolism / prevention & control*


  • Heparin