What is the preoperative management of patients with Antiphospholipid Syndrome (APS) on warfarin (Coumadin) undergoing a surgical procedure?

From the Guidelines

Preoperative management of patients with Antiphospholipid Syndrome (APS) on warfarin requires temporary discontinuation of warfarin and bridging with therapeutic-dose low molecular weight heparin (LMWH). The most recent and highest quality study 1 suggests that warfarin should be stopped 3 days before surgery to allow the INR to normalize (below 1.5), and LMWH bridging should begin 36 hours after the last warfarin dose.

Key Considerations

• The last dose of LMWH should be given 24 hours before surgery at half the therapeutic dose to minimize the risk of bleeding.
• For high-risk procedures with significant bleeding potential, LMWH may need to be stopped earlier (24-48 hours preoperatively).
• Patients should have their INR checked the day before surgery to ensure it's below 1.5, and if the INR remains elevated, vitamin K (1-2.5 mg orally) may be administered.
• Postoperatively, LMWH is typically resumed 24 hours after surgery if hemostasis is adequate, with warfarin restarted when the bleeding risk has sufficiently decreased.

Rationale

The bridging approach is necessary because APS patients have a high risk of thrombosis when anticoagulation is interrupted, while direct surgery under therapeutic anticoagulation would pose excessive bleeding risk. Although other studies 1 provide recommendations for preoperative management of patients on antithrombotic therapy, they are not directly applicable to APS patients on warfarin, and the study by 1 provides the most relevant and up-to-date guidance for this specific patient population.

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 The operative site should be sufficiently limited and accessible to permit the effective use of local procedures for hemostasis. Under these conditions, dental and minor surgical procedures may be performed without undue risk of hemorrhage. 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 preoperative management of patients with Antiphospholipid Syndrome (APS) on warfarin undergoing a surgical procedure involves:

• Close liaison between attending physicians, surgeons, and dentists
• PT/INR determination just prior to any surgical procedure
• Adjusting the dosage of warfarin to maintain the PT/INR at the low end of the therapeutic range for minimal invasive procedures
• Considering the benefits and risks of interrupting warfarin therapy for some surgical procedures 2

From the Research

Preoperative Management of Patients with APS on Warfarin

The preoperative management of patients with Antiphospholipid Syndrome (APS) on warfarin undergoing a surgical procedure involves several considerations to minimize the risk of thromboembolic and hemorrhagic complications.

• Bridging Therapy: The use of low molecular weight heparin (LMWH) as bridging therapy is a common approach in patients with APS on long-term warfarin therapy who require temporary interruption of anticoagulation for surgery 3, 4, 5.
• Timing of Warfarin Interruption: Warfarin should be interrupted 5 or 6 days before the procedure, and LMWH can be started 3 days before the procedure 5.
• LMWH Dosing: The dosing of LMWH can vary, but a common approach is to administer a therapeutic dose of LMWH, divided into two parts on the day of surgery, and then resume half of the individual dose of LMWH every 24 hours starting from day 2 after surgery 3.
• Resumption of Warfarin: Warfarin can be resumed on the evening of the procedure, and LMWH can be continued until the international normalized ratio (INR) is within the therapeutic target for 2 consecutive days 3, 5.
• Monitoring of Anticoagulation: Accurate assessment of anticoagulation intensity is essential to optimize anticoagulant dosing and minimize the risk of recurrent thrombosis or bleeding 6.

Special Considerations

• Lupus Anticoagulant: Lupus anticoagulant can affect phospholipid-dependent coagulation monitoring tests, and therefore, accurate assessment of anticoagulation intensity is crucial 6.
• Renal Impairment: Anticoagulant dosing and monitoring may require consideration in patients with APS-related severe renal impairment 6.
• Thrombocytopenia: Anticoagulant dosing and monitoring may also require consideration in patients with APS-related thrombocytopenia 6.
• Pregnancy: Anticoagulant dosing and monitoring may require special consideration during pregnancy 6.

Risks and Benefits

• Thromboembolic Risk: The risk of thromboembolic events is high in patients with APS, and therefore, anticoagulation therapy is essential to minimize this risk 7.
• Bleeding Risk: The risk of bleeding is also a consideration in patients with APS on anticoagulation therapy, and therefore, accurate assessment of anticoagulation intensity is crucial to minimize this risk 7.