Should we stop warfarin now and start Lovenox given an INR of 1.3, 7 days pre-procedure, with a planned warfarin hold in 3 days?

Management of Warfarin Interruption for Procedure with Current INR of 1.3

Given the current INR of 1.3 and being 7 days from the procedure with planned warfarin hold in 3 days, you should stop warfarin now and start Lovenox bridging therapy immediately, especially if the patient has high thrombotic risk factors.

Assessment of Current Situation

The patient's INR is already subtherapeutic at 1.3, which indicates:

• The patient is already approaching the target pre-procedure INR of <1.5
• Continuing warfarin for 3 more days would be unnecessary and could complicate management

Decision Algorithm Based on Thrombotic Risk

Step 1: Determine Patient's Thrombotic Risk

• High risk: Mechanical mitral valve, mechanical AVR with risk factors (AF, previous thromboembolism, LV dysfunction, hypercoagulable conditions, older-generation valves, or multiple mechanical valves) 1
• Low risk: Bileaflet mechanical AVR without risk factors 1

Step 2: Management Based on Risk

• For high-risk patients:

  • Stop warfarin now (7 days pre-procedure)
  • Start therapeutic Lovenox (LMWH) immediately at 100 U/kg every 12 hours 1
  • Continue Lovenox until 24 hours before procedure
  • Resume warfarin evening of procedure
  • Restart Lovenox 12-24 hours post-procedure if hemostasis achieved
  • Continue both until INR returns to therapeutic range 1

• For low-risk patients:

  • Stop warfarin now
  • No bridging anticoagulation needed 1
  • Resume warfarin within 24 hours after procedure

Rationale for Immediate Warfarin Discontinuation

1. Current INR is already 1.3:

   • The target pre-procedure INR is <1.5 1
   • The patient has already nearly reached this target
   • Continuing warfarin for 3 more days serves no purpose

2. Simplifies management:

   • Allows for a more predictable INR trajectory
   • Avoids potential INR fluctuations that could delay the procedure
   • Provides adequate time to establish bridging therapy if needed

Important Considerations

• Do not use vitamin K to reverse anticoagulation unless emergency reversal is needed, as this may create a hypercoagulable state 1

• For high-risk patients: The risk of thromboembolism when not anticoagulated can be 10-20% per year, making bridging therapy crucial 1

• Monitor INR prior to procedure to ensure it's <1.5 1

• Post-procedure management: Resume warfarin at usual dose the evening of the procedure if hemostasis is adequate 1

Potential Pitfalls to Avoid

1. Delaying bridging therapy in high-risk patients, which increases thrombotic risk

2. Administering vitamin K to lower INR, which may create resistance to re-warfarinization

3. Failing to restart anticoagulation promptly after the procedure, which increases thrombotic risk

4. Not checking INR before the procedure, which could lead to procedure cancellation if still elevated

By stopping warfarin now and initiating appropriate bridging therapy based on thrombotic risk, you'll optimize both procedural safety and thrombotic protection.