What is the approach for bridging anticoagulation in patients on warfarin (International Normalized Ratio (INR) antagonist) prior to a procedure?

From the Guidelines

Bridging anticoagulation for patients on warfarin before procedures is recommended for high thrombotic risk populations with full-dose, subcutaneous low molecular weight heparin (LMWH), such as enoxaparin 1 mg/kg twice daily or dalteparin 100 IU/kg twice daily, with the last dose given the morning of the day prior to the procedure at half the total daily dose 1.

Key Considerations

• The approach to bridging anticoagulation should be based on the patient's thromboembolic risk, with high-risk patients requiring bridging with therapeutic-dose LMWH.
• Warfarin can be resumed on the evening of the procedure or the day after the procedure at the patient's usual maintenance dose 1.
• Low-dose LMWH can be used for venous thromboembolism (VTE) prophylaxis for the first 24-72 hours post-procedure, with full-dose LMWH resumed 2-3 days post-procedure 1.

Bridging Protocol

• For high-risk patients, bridging with therapeutic-dose LMWH is recommended, with the last dose given the morning of the day prior to the procedure at half the total daily dose 1.
• After the procedure, warfarin can be resumed within 24 hours if hemostasis is adequate, and LMWH can be restarted 24-72 hours post-procedure depending on bleeding risk, continuing until the INR reaches the therapeutic range.

Important Notes

• The decision to bridge anticoagulation should be individualized based on the patient's risk of thromboembolism and bleeding 1.
• The use of LMWH for bridging anticoagulation provides more predictable anticoagulation with a shorter duration of action compared to warfarin, which has a long half-life and takes several days to clear from the system 1.

From the FDA Drug Label

The management of patients who undergo dental and surgical procedures requires close liaison between attending physicians, surgeons and dentists. In patients undergoing minimal invasive procedures who must be anticoagulated prior to, during, or immediately following these procedures, adjusting the dosage of warfarin sodium tablets to maintain the PT/INR at the low end of the therapeutic range may safely allow for continued anticoagulation Some dental or surgical procedures may necessitate the interruption of warfarin sodium tablets therapy When discontinuing warfarin sodium tablets even for a short period of time, the benefits and risks should be strongly considered. CONVERSION FROM HEPARIN THERAPY Since the anticoagulant effect of warfarin sodium tablets is delayed, heparin is preferred initially for rapid anticoagulation Conversion to warfarin sodium tablets may begin concomitantly with heparin therapy or may be delayed 3 to 6 days. To ensure continuous anticoagulation, it is advisable to continue full dose heparin therapy and that warfarin sodium tablets therapy be overlapped with heparin for 4 to 5 days, until warfarin sodium tablets have produced the desired therapeutic response as determined by PT/INR

The approach for bridging anticoagulation in patients on warfarin prior to a procedure involves:

• Adjusting the warfarin dosage to maintain the PT/INR at the low end of the therapeutic range for minimal invasive procedures
• Considering the interruption of warfarin therapy for some dental or surgical procedures
• Weighing the benefits and risks of discontinuing warfarin therapy even for a short period
• Using heparin for rapid anticoagulation and overlapping it with warfarin for 4 to 5 days to ensure continuous anticoagulation 2 Key considerations include:
• Close liaison between attending physicians, surgeons, and dentists
• Monitoring PT/INR levels to determine the therapeutic response to warfarin
• Being aware of the potential for heparin to affect PT/INR levels

From the Research

Bridging Anticoagulation in Patients on Warfarin

• The approach for bridging anticoagulation in patients on warfarin prior to a procedure involves the use of heparin until the International Normalized Ratio (INR) is in a therapeutic range 3, 4, 5.
• Unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) can be used for bridging therapy 3, 4, 5.
• The decision to use UFH or LMWH should be based on the individual patient's risk and the general bleeding risk of the procedure 3, 4, 5.

Comparison of UFH and LMWH

• Studies have compared the safety and efficacy of UFH and LMWH as bridging anticoagulants 4, 5.
• One study found that LMWH was associated with a lower risk of thromboembolic events, but a higher risk of bleeding 5.
• Another study found that UFH and LMWH had similar rates of overall adverse events, including thromboembolism and bleeding 5.

Patient-Specific Factors

• Patient-specific factors, such as renal function and comorbidities, should be considered when selecting a bridging anticoagulant 3, 5.
• Patients with renal insufficiency may require dose adjustments when using LMWH 3.
• Patients with multiple comorbidities may be at higher risk for bleeding complications when using UFH or LMWH 5.

Monitoring and Management

• Patients receiving bridging anticoagulation should be closely monitored for signs of bleeding or thrombosis 4, 5.
• The use of nonheparin anticoagulants, such as danaparoid or lepirudin, may be considered in patients with heparin-induced thrombocytopenia 6.
• Vitamin K antagonist therapy should be started only after the platelet count has substantially recovered in patients with heparin-induced thrombocytopenia 6.