From the Guidelines
Heparin bridging is indicated for patients at high risk of thromboembolism who require temporary interruption of oral anticoagulation therapy, particularly those with mechanical heart valves, recent venous thromboembolism, atrial fibrillation with high CHADS2 score, or recent arterial thromboembolism.
Indications for Heparin Bridging
The decision to use heparin bridging should be individualized, taking into account the trade-offs between thrombosis and bleeding risks 1.
- Mechanical heart valves, especially mitral position
- Recent venous thromboembolism (within 3 months)
- Atrial fibrillation with high CHADS2 score (≥5)
- Recent arterial thromboembolism
Bridging Regimen
The typical bridging regimen involves discontinuing warfarin 3 to 4 days before the procedure, initiating therapeutic-dose low molecular weight heparin (LMWH) such as enoxaparin 1 mg/kg twice daily or unfractionated heparin when the INR falls below 2.0, stopping heparin 24 hours (LMWH) or 4-6 hours (unfractionated heparin) before the procedure, and resuming both heparin and warfarin after the procedure when hemostasis is adequate 1.
Considerations
Not all patients on anticoagulation require bridging, as those with lower thrombotic risk may safely undergo temporary anticoagulation interruption without bridging therapy. The most recent guidelines suggest that heparin bridging should be used judiciously, considering the risks and benefits for each individual patient 1.
Administration
Heparin is continued until the INR returns to therapeutic range, providing continued anticoagulation during the perioperative period when warfarin's effect is subtherapeutic, balancing the competing risks of thromboembolism and procedural bleeding. According to the American College of Chest Physicians, heparin bridging is defined as the administration of a short-acting anticoagulant for an 8- to 10-day perioperative period during interruption of a VKA when the INR is below the therapeutic range 1.
From the FDA Drug Label
HEPARIN SODIUM INJECTION is an anticoagulant indicated for • Prophylaxis and treatment of venous thrombosis and pulmonary embolism • Prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdominothoracic surgery or who, for other reasons, are at risk of developing thromboembolic disease • Atrial fibrillation with embolization • Treatment of acute and chronic consumptive coagulopathies (disseminated intravascular coagulation) • Prevention of clotting in arterial and cardiac surgery • Prophylaxis and treatment of peripheral arterial embolism • Use as an anticoagulant in blood transfusions, extracorporeal circulation, and dialysis procedures
The indication for heparin bridge is not explicitly mentioned in the provided drug labels 2 and 2.
- Heparin is indicated for various conditions such as prophylaxis and treatment of venous thrombosis and pulmonary embolism, but heparin bridge is not directly mentioned.
- The provided labels do not directly support the use of heparin as a bridge therapy. The FDA drug label does not answer the question.
From the Research
Indications for Heparin Bridge
The decision to use heparin bridging therapy is based on the patient's risk of thromboembolism and bleeding. According to 3, heparin bridging is not necessary for most patients on chronic warfarin, except those at high risk of thromboembolism.
Patient Selection
The following factors should be considered when selecting patients for heparin bridging therapy:
- Thromboembolic risk: Patients with a high risk of thromboembolism, such as those with mechanical heart valves or atrial fibrillation, may require heparin bridging therapy 4, 5.
- Bleeding risk: Patients with a high risk of bleeding, such as those with renal insufficiency or liver disease, may not be suitable for heparin bridging therapy 6, 4.
- Type of anticoagulant: Patients on direct oral anticoagulants (DOACs) may not require heparin bridging therapy, as the risk of thromboembolism is lower compared to warfarin 3, 7.
Bridging Therapy Options
The choice of bridging therapy depends on the patient's individual needs and the type of procedure being performed. Options include:
- Unfractionated heparin (UFH): UFH is often used in patients with a high risk of thromboembolism or those undergoing major surgery 4, 5.
- Low-molecular-weight heparin (LMWH): LMWH is often used in patients with a lower risk of thromboembolism or those undergoing minor procedures 4, 5.
- Direct thrombin inhibitors: Direct thrombin inhibitors, such as dabigatran, may be used as an alternative to UFH or LMWH in certain patients 7.
Clinical Outcomes
Studies have shown that heparin bridging therapy increases the risk of major bleeding, but does not reduce the risk of thromboembolic events 3, 6. Therefore, the decision to use heparin bridging therapy should be made on a case-by-case basis, taking into account the patient's individual risk factors and the potential benefits and risks of therapy.