Acceptable INR for ERCP with Sphincterotomy
For ERCP with sphincterotomy, the INR must be below 1.5 to proceed safely. 1
Management Algorithm Based on Thrombotic Risk
For Patients at LOW Thrombotic Risk
Stop warfarin 5 days before the procedure: 1
- Check INR one week before the scheduled ERCP to assess baseline anticoagulation status 1
- Discontinue warfarin 5 days prior to the procedure 1
- Verify INR is <1.5 immediately before the procedure - this is the critical safety threshold 1
- Resume warfarin the evening of the procedure at the usual daily dose 1
- Recheck INR one week after the procedure to ensure adequate anticoagulation has been re-established 1
Low thrombotic risk conditions include: xenograft heart valves with CHADS₂ score <4, atrial fibrillation without high-risk features, and >3 months after venous thromboembolism 1
For Patients at HIGH Thrombotic Risk
Stop warfarin 5 days before AND use bridging anticoagulation: 1
- Discontinue warfarin 5 days prior to ERCP 1
- Start low molecular weight heparin (LMWH) 2 days after stopping warfarin 1
- Confirm INR <1.5 prior to the procedure 1
- Resume warfarin the evening of the procedure with the usual daily dose 1
- Check INR one week later to ensure therapeutic anticoagulation 1
High thrombotic risk conditions include: prosthetic metal heart valves (especially mitral position), atrial fibrillation with mitral stenosis, atrial fibrillation with previous stroke/TIA, recent stroke/TIA within 3 months, and recent venous thromboembolism while on anticoagulation 1
Rationale for INR <1.5 Threshold
ERCP with sphincterotomy is classified as a high-risk bleeding procedure by both the British Society of Gastroenterology and European Society of Gastrointestinal Endoscopy 1. The INR threshold of 1.5 balances procedural safety against thrombotic risk, as clinically significant hemorrhage occurs in 0.1-2% of sphincterotomies even under optimal conditions 2.
Critical Pitfalls to Avoid
Do not proceed if INR is ≥1.5: The guidelines are explicit that the INR must be verified below 1.5 immediately before the procedure, not just assumed based on timing of warfarin discontinuation 1. Individual patient metabolism of warfarin varies significantly.
Do not continue warfarin through the procedure: Unlike low-risk endoscopic procedures (diagnostic EGD, colonoscopy with biopsy, biliary stenting without sphincterotomy) where warfarin can be continued if INR is within therapeutic range, ERCP with sphincterotomy requires warfarin interruption regardless of baseline thrombotic risk 1.
If INR is above therapeutic range but <5 one week before the procedure: Reduce the daily warfarin dose until INR returns to therapeutic range, then proceed with the 5-day discontinuation protocol 1.
Post-Procedure Anticoagulation Resumption
Resume anticoagulation 2-3 days after the procedure depending on perceived hemorrhagic and thrombotic risks 1, 2. For patients at high thrombotic risk, consider earlier resumption with heparin bridging, preferably within 3 days 1. Patients should be counseled that there is an increased risk of post-procedure hemorrhage compared to non-anticoagulated patients, with delayed bleeding possible up to several weeks after sphincterotomy 1, 2.