Bridging anticoagulation with low-molecular-weight heparin after interruption of warfarin therapy is associated with a residual anticoagulant effect prior to surgery

Thromb Haemost. 2005 Sep;94(3):528-31. doi: 10.1160/TH05-01-0064.


Bridging anticoagulation with low-molecular-weight heparin (LMWH) is common in patients who require temporary interruption of warfarin before surgery or a procedure, but whether such patients have a residual anticoagulant effect just before a procedure is not known. Consecutive patients who received bridging anticoagulation with LMWH had anti-Xa levels measured just before a procedure. The proportion of patients with a residual anticoagulant effect, defined as an anti-Xa level > or = 0.10 IU/ml, was determined. Multivariable regression analysis identified predictors of a residual anticoagulant effect, expressed as an odds ratio (OR) and corresponding 95% confidence interval (CI). A pre-procedure residual anticoagulant effect was detected in 12 of 73 (16%) patients overall, in 11 of 37 (30%) patients who received therapeutic-dose LMWH, and in 1 of 36 patients (3%) who received low-dose LMWH. Receiving therapeutic-dose LMWH (OR = 118.8; 95% CI: 5.8, 999.9), and increasing age (OR = 4.0; 95% CI: 1.3, 12.5) were predictors of a residual pre-procedure anticoagulant effect. In patients who require bridging anticoagulation with LMWH, a residual anticoagulant effect from LMWH is detected in 1 of 6 patients, and receiving therapeutic-dose LMWH is the strongest predictor of such an effect.

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Anticoagulants / therapeutic use*
  • Blood Coagulation Disorders / drug therapy*
  • Body Weight
  • Factor Xa Inhibitors
  • Female
  • Hemorrhage / chemically induced
  • Heparin, Low-Molecular-Weight / adverse effects
  • Heparin, Low-Molecular-Weight / therapeutic use*
  • Humans
  • Male
  • Middle Aged
  • Preoperative Care* / methods
  • Risk Factors
  • Surgical Procedures, Operative*
  • Time Factors
  • Treatment Outcome
  • Warfarin / therapeutic use*


  • Anticoagulants
  • Factor Xa Inhibitors
  • Heparin, Low-Molecular-Weight
  • Warfarin