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

James D. Douketis; Karen Woods; Gary A. Foster; Mark A. Crowther

doi:10.1160/TH05-01-0064

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2005; 94(03): 528-531
DOI: 10.1160/TH05-01-0064

Blood Coagulation, Fibrinolysis and Cellular Haemostasis

Schattauer GmbH

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

James D. Douketis

¹Department of Medicine and St. Joseph’s Heathcare

,

Karen Woods

¹Department of Medicine and St. Joseph’s Heathcare

,

Gary A. Foster

²the Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Canada

,

Mark A. Crowther

¹Department of Medicine and St. Joseph’s Heathcare

› Author Affiliations

Abstract

Summary

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 ≥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.

Keywords

Low-molecular-weight heparin - surgery - anti-factor Xa - warfarin

Full Text

References

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