What are the recommended anticoagulation regimens for conditions such as atrial fibrillation, Deep Vein Thrombosis (DVT), and Pulmonary Embolism (PE)?

Recommended Anticoagulation Regimens for Atrial Fibrillation, DVT, and PE

Direct oral anticoagulants (DOACs) such as apixaban, dabigatran, edoxaban, or rivaroxaban are the first-line therapy for atrial fibrillation, DVT, and PE due to their efficacy, safety profile, and convenience compared to traditional vitamin K antagonists. 1

Atrial Fibrillation Anticoagulation

Patient Selection and Risk Assessment

• Anticoagulation is indicated for patients with nonvalvular atrial fibrillation at intermediate or high risk of stroke (CHADS₂ score ≥1) 2
• For valvular atrial fibrillation (particularly with mechanical heart valves), vitamin K antagonists (warfarin) remain the only recommended option 3

First-line Therapy for Nonvalvular AF

• DOACs are preferred over warfarin for stroke prevention in nonvalvular AF 1, 3
• Recommended DOAC options:
  • Apixaban: 5 mg twice daily (2.5 mg twice daily if ≥2 of: age ≥80 years, weight ≤60 kg, serum creatinine ≥1.5 mg/dL) 4
  • Dabigatran: 150 mg twice daily (110 mg twice daily for high bleeding risk)
  • Rivaroxaban: 20 mg daily with food (15 mg daily if CrCl 15-50 mL/min)
  • Edoxaban: 60 mg daily (30 mg daily if CrCl 15-50 mL/min or weight ≤60 kg)

Second-line Therapy

• Warfarin with target INR 2.0-3.0 (if DOACs contraindicated or not tolerated) 5
• Regular INR monitoring required

Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE)

Initial Treatment

• For most patients with DVT or PE, DOACs that don't require initial parenteral therapy are preferred:

  • Apixaban: 10 mg twice daily for 7 days, then 5 mg twice daily 1, 4
  • Rivaroxaban: 15 mg twice daily for 21 days, then 20 mg once daily

• Alternative approach (requires overlap):

  • LMWH (e.g., enoxaparin 1 mg/kg twice daily) for at least 5 days 5, 1
  • Start warfarin simultaneously with LMWH
  • Continue LMWH until INR ≥2.0 for at least 24 hours
  • Continue warfarin with target INR 2.0-3.0 (target 2.5) 5

Special Considerations for PE

• For PE with hypotension (systolic BP <90 mmHg) and low bleeding risk: systemic thrombolytic therapy 5
• For high-risk PE without hypotension but at risk of deterioration: consider thrombolysis 5
• For PE with contraindications to anticoagulation: IVC filter placement 5
• For PE with hypotension and contraindications to thrombolysis: consider catheter-assisted thrombus removal or surgical pulmonary embolectomy if expertise available 5

Cancer-Associated Thrombosis

• LMWH is traditionally preferred over warfarin 5, 1
  • Enoxaparin: 1 mg/kg twice daily or 1.5 mg/kg once daily
  • Dalteparin: 200 U/kg once daily for first month, then 150 U/kg once daily
• Growing evidence supports DOACs in select cancer patients with low bleeding risk 3

Duration of Anticoagulation

DVT/PE Provoked by Surgery

• 3 months of anticoagulation (not shorter, not longer) 5

DVT/PE Provoked by Nonsurgical Transient Risk Factor

• 3 months of anticoagulation 5
• Extended therapy not recommended, especially with high bleeding risk

Unprovoked DVT/PE

• Minimum 3 months of anticoagulation 5
• First unprovoked event:
  • Low/moderate bleeding risk: consider extended therapy 5
  • High bleeding risk: stop after 3 months 5
• Second unprovoked event:
  • Low bleeding risk: extended therapy strongly recommended 5
  • Moderate bleeding risk: extended therapy suggested 5
  • High bleeding risk: stop after 3 months 5

Cancer-Associated DVT/PE

• Extended anticoagulation recommended while cancer is active 5
• Annual reassessment of risk-benefit ratio 5

Practical Considerations

Monitoring

• DOACs: No routine coagulation monitoring required
• Warfarin: Regular INR monitoring to maintain 2.0-3.0 5
• Baseline testing: CBC, renal/hepatic function, aPTT, PT/INR 1

Bleeding Management

• Major bleeding on warfarin: Vitamin K and 4-factor prothrombin complex concentrate 3
• Dabigatran reversal: Idarucizumab
• Rivaroxaban/apixaban reversal: Andexanet alfa 3

Drug Interactions

• Avoid combining DOACs with strong P-gp inducers like phenytoin 6
• For patients requiring phenytoin who need anticoagulation, warfarin is preferred 6

Perioperative Management

• Warfarin: Stop 5 days before major surgery, restart 12-24 hours after 7
• DOACs: Generally stop 24-48 hours before procedures (timing depends on renal function and bleeding risk)
• Bridging therapy decisions based on thromboembolism vs. bleeding risk 7

Remember that anticoagulation therapy requires regular assessment of bleeding risk, and the continuing use of extended therapy should be reassessed periodically (e.g., annually) 5.