How do you bridge anticoagulation for patients on warfarin (Coumadin) who require temporary interruption for procedures?

Bridging Anticoagulation for Patients on Warfarin Requiring Temporary Interruption

Bridging anticoagulation should only be used in patients at high risk of thromboembolism, as it increases bleeding risk without reducing thrombotic events in most patients. 1, 2

Risk Stratification for Bridging Therapy

High Thromboembolism Risk (Bridging Recommended)

• Mechanical mitral valve 1, 2
• Prosthetic valve with atrial fibrillation 1, 2
• Non-valvular atrial fibrillation with CHA₂DS₂-VASc score >5 1, 2
• Recent venous thromboembolism (<3 months) 2
• Severe thrombophilia (protein C or S deficiency, antiphospholipid syndrome) 1, 2

Moderate to Low Risk (Bridging Not Recommended)

• Atrial fibrillation with CHA₂DS₂-VASc score ≤5 1
• Stable coronary artery disease 1
• Low-risk thrombophilias 2

Standard Bridging Protocol

Pre-Procedure Management

• Stop warfarin 5 days before the procedure 1, 2
• Check baseline labs (hemoglobin, platelet count, creatinine, INR) 2
• For high-risk patients, start LMWH 3 days before the procedure 1, 2, 3
  • Therapeutic dose: 1 mg/kg twice daily or 1.5 mg/kg once daily 2, 3
  • Half-therapeutic dose (1 mg/kg once daily) may be considered for intermediate risk patients 4
• Administer last pre-procedural LMWH dose no less than 24 hours before surgery at half the total daily dose 2
• Ensure INR is ≤1.5 before proceeding with the procedure 1, 2

Post-Procedure Management

• Resume warfarin on the evening of or the day after the procedure (12-24 hours post-procedure) 1, 2

For Low Bleeding Risk Procedures:

• Resume LMWH at the previous dose 24 hours after the procedure 2, 3
• Continue LMWH until the INR reaches the therapeutic range (≥2.0) 2, 3

For High Bleeding Risk Procedures:

• Resume warfarin on the evening of the procedure 2, 3
• Delay LMWH resumption for 48-72 hours post-procedure 2, 3
• Consider a boost dose of warfarin (50% increase) for the first 2 postoperative days to reach therapeutic INR faster 1

Special Considerations

Minor Procedures

• For minor procedures with minimal bleeding risk (dental extractions, cataract surgery, skin biopsies), warfarin may be continued without interruption 1, 2
• For pacemaker/defibrillator implantation and vascular interventions, continuing warfarin may be safer than bridging 2

Renal Impairment

• Adjust LMWH dosing based on renal function 2
• Consider unfractionated heparin instead of LMWH for patients with severe renal insufficiency 2

Evidence on Bridging Outcomes

• Recent studies show that bridging therapy is associated with a two to three-fold increase in major bleeding risk without reducing thromboembolism 5
• The BRIDGE trial demonstrated that absence of bridging was non-inferior to bridging with LMWH for prevention of arterial thromboembolism and decreased bleeding risk 1
• A register-based cohort study found no benefit from LMWH bridging regardless of indication for warfarin treatment 6

Common Pitfalls and Caveats

• Overuse of bridging therapy in low-risk patients increases bleeding complications without providing thrombotic protection 1, 5
• Failure to adjust post-procedural anticoagulation timing based on bleeding risk can lead to hemorrhagic complications 2, 3
• Inadequate communication between healthcare providers involved in perioperative care can lead to management errors 2
• Resuming full-dose anticoagulation too early after high bleeding risk procedures increases risk of major bleeding 3, 5
• INR should be checked before the procedure to ensure adequate reversal of warfarin effect (target INR ≤1.5) 1, 2