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

Bridging Anticoagulation for Patients on Warfarin Prior to Procedures

For patients on warfarin requiring temporary interruption for procedures, bridging anticoagulation should be reserved only for those at high thromboembolic risk, while most patients can safely undergo warfarin interruption without bridging. 1

Risk Stratification for Bridging Decisions

High Thromboembolic Risk (Bridging Recommended)

• Mechanical heart valves (especially older-generation valves or mitral position) 1
• Recent venous thromboembolism (<3 months) 1
• Atrial fibrillation with CHADS₂ score ≥5 1, 2
• Recent stroke or TIA (<3 months) 1
• Active cancer with thrombosis 1
• Thrombophilia syndromes 1, 2

Low Thromboembolic Risk (No Bridging Needed)

• Bileaflet mechanical aortic valve without other risk factors 1
• Atrial fibrillation with lower CHADS₂ scores 1
• VTE >3 months ago without thrombophilia 1

Standard Protocol for Warfarin Interruption

Pre-Procedure Management

1. Stop warfarin 5 days before the procedure 1, 3
2. Check INR before the procedure; proceed if INR ≤1.5 1
3. For high-risk patients requiring bridging:
   • Start LMWH (e.g., enoxaparin 1 mg/kg twice daily or dalteparin 100 IU/kg twice daily) when INR falls below 2.0, typically 3 days before procedure 1, 2
   • Administer last dose of LMWH at least 24 hours before procedure 1

Post-Procedure Management

1. Resume warfarin on the evening of or day after procedure at previous maintenance dose 1, 3
2. For high-risk patients with adequate hemostasis:
   • Resume therapeutic-dose LMWH 24 hours after minor procedures 1
   • Delay LMWH resumption for 48-72 hours after major procedures with high bleeding risk 1
3. Continue LMWH until INR returns to therapeutic range (typically 2.0 or above) 1, 3

Special Considerations

Procedure-Specific Recommendations

• Low bleeding risk procedures (cataract surgery, dental extractions): Consider continuing warfarin without interruption 1
• High bleeding risk procedures: Delay resumption of therapeutic anticoagulation for 48-72 hours 1

Urgent Reversal for Emergency Procedures

• For urgent procedures requiring immediate reversal:
  • Administer vitamin K 2.5-5 mg IV/oral 1
  • Consider prothrombin complex concentrate for more immediate reversal 1

Important Caveats

1. Bridging increases bleeding risk: Recent evidence shows a 2-3 fold increase in major bleeding with bridging therapy without reduction in thromboembolic events for most patients 4

2. Duration of bridging: In clinical practice, bridging therapy often extends longer than anticipated (median 7.5 days), increasing both costs and potential complications 5

3. DOACs vs. warfarin: Unlike warfarin, Direct Oral Anticoagulants (DOACs) do not require bridging due to their short half-lives 2

4. Monitoring requirements: Check INR before the procedure to ensure it's ≤1.5, and monitor regularly after warfarin resumption 1, 3

5. Mechanical heart valves: These patients represent a special population where bridging evidence is strongest, particularly for older valve types or mitral position 1

By following this structured approach to perioperative anticoagulation management, clinicians can minimize both thromboembolic and bleeding complications in patients requiring temporary warfarin interruption for procedures.