When should warfarin (anticoagulant) be stopped?

When to Stop Warfarin

Stop warfarin 5 days before high-risk procedures to allow INR to normalize to <1.5, and resume 12-24 hours postoperatively once hemostasis is achieved. 1

Perioperative Management

Low-Risk Procedures (Minor Bleeding Expected)

• Continue warfarin without interruption for procedures where bleeding is easily controlled, such as dental extractions, cataract surgery, or skin procedures 1, 2
• Verify INR is within therapeutic range during the week before the procedure 2

High-Risk Procedures (Major Surgery)

Standard approach for most patients:

• Stop warfarin 2-4 days before surgery (typically 5 days to ensure INR <1.5) 1
• Check INR prior to procedure to confirm it is <1.5 1, 2
• Resume warfarin at usual dose 12-24 hours postoperatively once bleeding risk is acceptable 1

Accelerated reversal option:

• Give vitamin K 2.5 mg orally 2 days before procedure to reduce warfarin-free period to 2 days 1, 3
• Avoid high-dose vitamin K as this creates difficulty re-establishing therapeutic INR 1

Bridging Therapy Decisions

Patients Who DO NOT Need Bridging (Low Thrombotic Risk)

• Bileaflet mechanical aortic valve without other risk factors - temporary interruption without bridging is recommended 1
• Atrial fibrillation without high-risk features 1
• Recent evidence shows bridging significantly increases bleeding risk (3.2% vs 1.3%) without reducing thromboembolism 1

Patients Who REQUIRE Bridging (High Thrombotic Risk)

Start therapeutic LMWH or unfractionated heparin when INR falls below 2.0: 1

• Mechanical mitral valve (any type) 1
• Any mechanical valve with atrial fibrillation 1
• Older-generation mechanical valves (caged ball or disc) 1
• Venous thromboembolism within 3 months 1
• Previous thromboembolism while anticoagulated 1, 3
• Multiple mechanical valves 1
• Left ventricular dysfunction (LVEF <30%) 1
• High-risk thrombophilia syndromes (antiphospholipid syndrome, protein C/S deficiency) 1

Bridging protocol:

• Stop warfarin 4-5 days before procedure 1, 3
• Start therapeutic LMWH (100 U/kg every 12 hours) or unfractionated heparin (15,000 U every 12 hours subcutaneously) when INR falls below therapeutic range 1, 3
• Give last dose of LMWH at least 24 hours before procedure 2, 3
• Resume LMWH 48 hours postoperatively for high thrombotic risk patients 1

Management of Acute Bleeding

Active Gastrointestinal Bleeding

• Interrupt warfarin immediately at presentation 1
• For unstable hemorrhage, reverse with prothrombin complex concentrate and vitamin K 1
• Restart warfarin 7-15 days after bleeding stops - this timing reduces thromboembolism and mortality without increasing rebleeding 1
• Starting before 7 days doubles rebleeding risk 1

Life-Threatening Bleeding

• Reverse with fresh frozen plasma or intravenous prothrombin complex concentrate 1
• Add low-dose vitamin K (1-2 mg) as prothrombin complex has shorter half-life than warfarin 1

Permanent Discontinuation Considerations

Warfarin should be discontinued when: 4

• Purple toes syndrome develops (dark purplish toes occurring 3-10 weeks after initiation) 4
• Skin necrosis occurs (usually within first few days of therapy) 4
• Systemic cholesterol microembolization signs appear 4
• Risk of bleeding exceeds thrombotic protection benefit 1

Common Pitfalls

• Do not use high-dose vitamin K for routine preoperative reversal - this creates hypercoagulable state and difficulty re-establishing therapeutic INR 1
• Do not bridge low-risk patients - this triples bleeding risk without benefit 1
• Do not restart warfarin too early after GI bleeding - wait minimum 7 days to avoid doubling rebleeding risk 1
• Do not stop warfarin for minor procedures - continuation is safer than interruption for dental work, cataract surgery, or skin procedures 1, 2
• Monitor elderly patients closely - they require 1 mg/day less warfarin and have higher bleeding risk even at therapeutic INR 1