What is the recommended perioperative management of warfarin (anticoagulant), including hold times and bridging with low molecular weight heparin (LMWH) or unfractionated heparin (UFH), for patients undergoing surgery?

From the Guidelines

Perioperative management of warfarin typically requires discontinuation 5 days before surgery to allow the INR to normalize (below 1.5). For patients at high thrombotic risk (such as those with mechanical heart valves, recent venous thromboembolism within 3 months, or atrial fibrillation with prior stroke), bridging anticoagulation is recommended 1.

Key Considerations:

• Bridging involves starting LMWH (enoxaparin 1 mg/kg twice daily or 1.5 mg/kg once daily) or UFH (typically as an inpatient infusion with a target aPTT of 1.5-2.5 times normal) after the INR falls below 2.0, usually 2-3 days after stopping warfarin.
• The last dose of LMWH should be given 24 hours before surgery (using half the usual dose), while UFH should be discontinued 4-6 hours preoperatively.
• Postoperatively, warfarin can be resumed 12-24 hours after surgery when hemostasis is adequate, typically at the patient's usual maintenance dose.
• Bridging with LMWH or UFH should be restarted 24-72 hours after surgery depending on bleeding risk, and continued until the INR returns to therapeutic range (usually 2.0-3.0) 1.

Patient-Specific Factors:

• The decision to bridge should be individualized based on patient-specific thrombotic and hemorrhagic risk factors.
• Patients at low risk for thrombosis may not require bridging, while those at high risk may benefit from more aggressive anticoagulation strategies.
• The type of surgical procedure and the patient's overall health status should also be taken into account when determining the best approach to perioperative anticoagulation management 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. PT/INR determination is recommended just prior to any dental or surgical procedure. 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.

The recommended perioperative management of warfarin includes:

• PT/INR determination just prior to any dental or surgical procedure
• Adjusting the dosage of warfarin to maintain the PT/INR at the low end of the therapeutic range for minimal invasive procedures
• Interrupting warfarin therapy for some dental or surgical procedures, with consideration of the benefits and risks
• Close liaison between attending physicians, surgeons, and dentists for management of patients undergoing dental and surgical procedures 2 Bridging with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) is not directly addressed in the provided drug label. Hold times for warfarin are not explicitly stated in the label, but it is recommended to consider the benefits and risks when discontinuing warfarin sodium tablets even for a short period of time.

From the Research

Perioperative Management of Warfarin

The management of warfarin in the perioperative period is crucial to balance the risk of thromboembolism and bleeding complications. The following are key points to consider:

• Warfarin should be held for a certain period before surgery to reduce the risk of bleeding complications 3, 4.
• The hold time for warfarin varies depending on the type of surgery and the patient's risk factors for thromboembolism 5, 6.
• Bridging anticoagulation with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) may be necessary for patients at high risk of thromboembolism 3, 6.

Bridging Anticoagulation

Bridging anticoagulation is used to prevent thromboembolism in patients who are at high risk while they are off warfarin. The following are key points to consider:

• LMWH is a commonly used bridging anticoagulant due to its ease of use and lower risk of bleeding complications compared to UFH 3, 6.
• The duration of bridging anticoagulation varies depending on the patient's risk factors and the type of surgery 3, 6.
• The safety and efficacy of LMWH as a bridging anticoagulant have been demonstrated in several studies 3, 6.

Monitoring of Warfarin

Monitoring of warfarin is crucial to ensure that the patient's international normalized ratio (INR) is within the therapeutic range. The following are key points to consider:

• The INR should be checked regularly to ensure that it is within the therapeutic range 5, 4.
• The INR level is not always a reliable predictor of bleeding complications, and other factors such as the patient's overall health and the type of surgery should also be considered 7.
• A preoperative INR check is recommended to ensure that the patient's warfarin is within the therapeutic range 4, 7.

Hold Times and Bridging

The hold times for warfarin and the need for bridging anticoagulation vary depending on the patient's risk factors and the type of surgery. The following are key points to consider:

• For patients undergoing cutaneous surgery, warfarin can be continued with a preoperative INR check to ensure that it is within the therapeutic range 4, 7.
• For patients undergoing mechanical heart valve replacement, bridging anticoagulation with LMWH or UFH may be necessary to prevent thromboembolism 5, 6.
• The hold time for warfarin and the need for bridging anticoagulation should be individualized based on the patient's risk factors and the type of surgery 3, 5, 6.