From the Guidelines
When doing warfarin bridging, Clexane (enoxaparin) should be administered at a therapeutic dose for patients at high thrombotic risk, but may not always require therapeutic dosing for those at lower risk. The decision to use therapeutic or prophylactic dosing of Clexane should be individualized based on the patient's thrombotic risk versus bleeding risk, as stated in the American College of Chest Physicians clinical practice guideline 1. Some key points to consider when administering heparin bridging include:
- Bridging is most often done with a low molecular weight heparin (LMWH), typically with a therapeutic-dose regimen, administered with the intent of preventing arterial thromboembolism (ATE) 1.
- Therapeutic-dose regimens, such as enoxaparin 1 mg/kg bid or dalteparin 100 IU/kg bid, are commonly used for bridging 1.
- Intermediate-dose regimens, such as enoxaparin 40 mg bid, may also be used in certain situations 1.
- Post-operative heparin bridging should be initiated when there is adequate surgical/procedure-site hemostasis and the patient is at a relatively low risk for bleeding 1.
- The administration of heparin bridging, particularly if only used pre-operatively, does not preclude the administration of post-operative low-dose LMWH 1. In terms of specific dosing, therapeutic dosing of enoxaparin is typically 1 mg/kg twice daily or 1.5 mg/kg once daily, while prophylactic dosing is usually 40 mg once daily for normal weight patients 1. Renal function must be considered when dosing enoxaparin, with dose reductions needed for patients with impaired kidney function 1. Bridging typically begins 2-3 days before warfarin interruption and continues until the INR returns to the therapeutic range after warfarin is restarted 1.
From the Research
Warfarin Bridging with Clexane
- The question of whether Clexane (enoxaparin) needs to be at a therapeutic dose during warfarin bridging is addressed in several studies 2, 3, 4, 5, 6.
- A study from 2010 found that a half-therapeutic dose of enoxaparin was safe and effective for bridging in patients with an intermediate risk of thromboembolic events 4.
- Another study from 2010 evaluated the long-term efficacy and safety of once-daily enoxaparin plus warfarin for the outpatient treatment of lower-limb deep vein thrombosis, and found that this regimen was effective and safe 5.
- However, the optimal dose of enoxaparin for bridging is still a matter of debate, and the 8th ACCP Guidelines recommend therapeutic-dose or low-dose low molecular weight heparin after stratification of the thromboembolic risk 4.
- A study from 2008 found that patients with stable INRs while receiving warfarin who experience a significant subtherapeutic INR value have a low risk of thromboembolism, and that bridging with anticoagulant therapy may not be necessary in these cases 2.
- In terms of specific dosing, a study from 2006 used subcutaneous enoxaparin 1.0 mg/kg every 12 hours for 5 days, followed by 1.0 mg/kg daily for 175 days, or subcutaneous enoxaparin 1.0 mg/kg every 12 hours for at least 5 days and until a stable international normalized ratio of 2 to 3 was achieved on oral warfarin 3.
- A study from 2015 compared the usefulness of enoxaparin versus warfarin for prevention of left ventricular mural thrombus after anterior wall acute myocardial infarction, and found that enoxaparin tended to shorten hospitalization and lower cost of care, but may have higher rates of LV thrombus at 3.5 months 6.