What are the recommendations for anticoagulation (anti-coagulation) therapy?

Anticoagulation Therapy Recommendations

For most patients requiring anticoagulation, direct oral anticoagulants (DOACs) are preferred over warfarin due to superior safety profiles and ease of use, with specific agent selection based on indication, renal function, and patient-specific factors. 1

Selection by Clinical Indication

Atrial Fibrillation (Non-Valvular)

Use CHA₂DS₂-VASc score to determine need for anticoagulation: 1

• Score ≥2: Oral anticoagulation is mandatory. Options include warfarin, dabigatran, rivaroxaban, or apixaban 1
• Score of 1: Either no therapy, oral anticoagulant, or aspirin may be considered 1
• Score of 0: Reasonable to omit antithrombotic therapy 1

Preferred agents for non-valvular AF: DOACs (dabigatran, rivaroxaban, apixaban, or edoxaban) are suggested over warfarin 1, 2

Absolute contraindications to DOACs in AF:

• Mechanical heart valves (dabigatran specifically contraindicated and caused harm in trials) 1
• Rheumatic mitral stenosis 1
• End-stage chronic kidney disease (CrCl <15 mL/min) or hemodialysis—use warfarin with target INR 2.0-3.0 1

Venous Thromboembolism (DVT/PE)

For acute proximal DVT or PE without cancer: 1

• First-line: DOAC therapy (dabigatran, rivaroxaban, apixaban, or edoxaban) over warfarin for the initial 3 months 1
• Alternative: If DOACs not used, warfarin (target INR 2.5, range 2.0-3.0) over LMWH 1

For VTE with active cancer: 1

• First-line: LMWH over warfarin for the initial 3 months 1
• Second-line: LMWH over DOACs (dabigatran, rivaroxaban, apixaban, or edoxaban) 1

Duration of therapy for VTE: 1

• Provoked by surgery: 3 months of anticoagulation, then stop 1
• Provoked by non-surgical transient risk factor: 3 months of anticoagulation 1
• Unprovoked VTE: Minimum 3 months, then evaluate for extended therapy (indefinite duration) 1
• Recurrent VTE: Extended therapy with no scheduled stop date 1, 3

Mechanical Heart Valves

Warfarin is mandatory—DOACs are contraindicated: 1, 3

• St. Jude bileaflet valve (aortic position): Target INR 2.5 (range 2.0-3.0) 3
• Tilting disk or bileaflet valves (mitral position): Target INR 3.0 (range 2.5-3.5) 3
• Caged ball or caged disk valves: Target INR 3.0 (range 2.5-3.5) plus aspirin 75-100 mg daily 3

Special Populations Requiring Warfarin Over DOACs

Antiphospholipid syndrome: Adjusted-dose warfarin (target INR 2.5) is suggested over DOAC therapy 1, 4

Extreme obesity (≥120 kg): While recent data suggest DOACs may be effective, warfarin remains preferred when anticoagulant levels cannot be reliably monitored 4, 5

High gastrointestinal bleeding risk: Warfarin may be preferred as some DOACs increase GI bleeding risk 4

DOAC Dosing Considerations

Apixaban dose reduction criteria (must meet ≥2 of the following): 6

• Age ≥80 years
• Weight ≤60 kg
• Serum creatinine ≥1.5 mg/dL

Standard dose: 5 mg twice daily 6 Reduced dose: 2.5 mg twice daily when meeting reduction criteria 6

Renal function monitoring: Evaluate creatinine clearance before initiating any DOAC and reassess at least annually 1

Warfarin Management

Initial dosing: Start with 2-5 mg daily (lower doses for elderly, debilitated, or those with genetic variations in CYP2C9/VKORC1) 3

Monitoring frequency: 3

• Daily INR checks until stable in therapeutic range
• Once stable, INR checks every 1-4 weeks
• Additional testing when medications are started, stopped, or taken irregularly

Bridging therapy: 1

• Mechanical heart valves: Bridging with UFH or LMWH is recommended when warfarin is interrupted 1
• Non-valvular AF: Balance stroke and bleeding risks against duration off anticoagulation 1

Perioperative Management

For patients on DOACs: Interrupt therapy without bridging with LMWH—resume postoperatively based on bleeding risk 7

For patients on warfarin: 3

• Stop warfarin 5 days before major surgery
• Resume 12-24 hours postoperatively
• For minor procedures with adequate hemostasis, adjust to low end of therapeutic range rather than stopping 3

Reversal Agents

Life-threatening bleeding on DOACs: 7, 8

• Dabigatran: Idarucizumab (specific reversal agent) 7, 8
• Apixaban or rivaroxaban: Andexanet alfa (specific reversal agent) 7, 8
• If specific agents unavailable: Prothrombin complex concentrates or activated prothrombin complex concentrates 7

Warfarin reversal: Vitamin K, fresh frozen plasma, or prothrombin complex concentrates depending on urgency 3

Critical Documentation Elements

Always document: 6

• Indication for anticoagulation
• Rationale for agent selection (especially if using reduced DOAC dosing)
• Patient's weight, age, and renal function as they relate to dosing
• Planned duration of therapy and next reassessment date
• Bleeding risk assessment

Common Pitfalls to Avoid

Do not use dabigatran with mechanical heart valves—this caused increased thromboembolic and bleeding events in trials 1

Do not use DOACs in end-stage renal disease or dialysis—lack of safety data and risk of drug accumulation 1

Do not assume all DOACs are interchangeable—dosing, indications, and contraindications vary by agent 1, 7

Do not forget to reassess anticoagulation need periodically—particularly for extended therapy, evaluate risk-benefit at least annually 1

Do not omit renal function monitoring—all DOACs require periodic assessment to avoid drug accumulation 1