How long should warfarin (anticoagulant) be held before a procedure?

Warfarin Should Be Stopped 5 Days Before Most Procedures

For patients requiring temporary interruption of warfarin before surgery or invasive procedures, stop warfarin approximately 5 days (4 doses) before the procedure and verify that the INR is <1.5 immediately prior to the procedure. 1

Procedure Risk Stratification

Low-Risk Procedures (Continue Warfarin)

• For low bleeding risk procedures, continue warfarin without interruption and check INR during the week before the procedure to ensure it remains within therapeutic range. 2, 3
• Low-risk procedures include:
  • Diagnostic endoscopy with or without biopsy 3
  • Simple dental extractions (target INR ≤3.5) 4
  • Breast core needle biopsy 2
  • Biliary or pancreatic stenting without sphincterotomy 3

High-Risk Procedures (Stop Warfarin 5 Days Before)

• Stop warfarin 5 days before high bleeding risk procedures to allow normalization of INR to <1.5. 1, 3
• High-risk procedures include:
  • Polypectomy, endoscopic mucosal resection 3
  • ERCP with sphincterotomy 3
  • Major surgery requiring general anesthesia 1
  • Procedures requiring spinal/epidural anesthesia (INR verification mandatory) 3

Critical Pre-Procedure INR Verification

**Always check INR on the day before or morning of the procedure to confirm it is <1.5**, as approximately 7% of patients will still have an INR >1.5 after 5 days of warfarin discontinuation. 1, 3 This verification is particularly crucial because:

• Age significantly predicts slower INR normalization (6.8% slower decrease per decade of age) 5
• Baseline INR >3.0 is associated with delayed normalization 6
• The INR decreases exponentially with wide interpatient variation 5

Bridging Anticoagulation Decision

High Thrombotic Risk (Requires Bridging)

For patients at high thrombotic risk, bridge with therapeutic-dose LMWH starting 2 days after stopping warfarin, with the last LMWH dose given at least 24 hours before the procedure. 2, 3 High-risk patients include:

• Prosthetic metal heart valve 3
• Atrial fibrillation with mitral stenosis or prior stroke/TIA 3
• CHADS₂ score ≥5 3
• Recent venous thromboembolism 3

Low Thrombotic Risk (No Bridging)

For patients at low thrombotic risk undergoing high-risk procedures, do not use bridging anticoagulation. 2, 3 Simply stop warfarin 5 days before and resume postoperatively.

Postoperative Warfarin Resumption

Resume warfarin at the usual maintenance dose on the evening of surgery or the next morning (12-24 hours postoperatively) when there is adequate hemostasis. 1, 2 The mean time to achieve therapeutic INR (≥2.0) is approximately 5 days after resumption. 1

LMWH Restart Timing (If Bridging)

• For high bleeding risk procedures: delay LMWH restart for 48-72 hours post-procedure 3
• For low bleeding risk procedures: restart LMWH at previous dose within 24 hours 3
• Continue LMWH until INR is therapeutic for 2 consecutive days 3

Common Pitfalls to Avoid

Do not assume 5 days is always sufficient without INR verification, as 7% of patients will have inadequate normalization. 1, 3

Do not give routine vitamin K for INR 1.5-1.9 measured 1-2 days before surgery, as this causes postoperative warfarin resistance without proven benefit. 3

Do not resume full-dose LMWH too early post-procedure, as this causes major bleeding in up to 20% of patients. 3

Do not stop warfarin for minor procedures unnecessarily, as this creates avoidable thromboembolic risk without benefit. 4