What is the recommended anticoagulation therapy for patients with atrial fibrillation (AF) not due to rheumatic heart disease, using the Cha2ds2-Vasc score?

Anticoagulation Therapy for Atrial Fibrillation Based on CHA2DS2-VASc Score

Direct oral anticoagulants (DOACs) are recommended over warfarin for stroke prevention in patients with atrial fibrillation who have a CHA2DS2-VASc score ≥1 in men or ≥2 in women, except in those with moderate to severe mitral stenosis or mechanical heart valves. 1

Risk Assessment Using CHA2DS2-VASc Score

The CHA2DS2-VASc score is the recommended tool for stroke risk assessment in patients with AF:

• CHA2DS2-VASc components (points):
  • Congestive heart failure (1)
  • Hypertension (1)
  • Age ≥75 years (2)
  • Diabetes mellitus (1)
  • Prior Stroke/TIA/thromboembolism (2)
  • Vascular disease (1)
  • Age 65-74 years (1)
  • Sex category = female (1) 1

Recommendations Based on CHA2DS2-VASc Score

Low Risk Patients

• CHA2DS2-VASc score = 0 in men or 1 in women (due to female sex alone):
  • No anticoagulation therapy recommended 1
  • Annual stroke risk is very low (0.84% per year) 2, 3

Intermediate to High Risk Patients

• CHA2DS2-VASc score ≥1 in men or ≥2 in women:
  • Oral anticoagulation therapy is recommended 1
  • Risk increases substantially with each additional point (annual stroke rates):
    • Score 1: 1.79% per year
    • Score 2: 3.67% per year
    • Score 3: 5.75% per year
    • Score 4: 8.18% per year 2

Choice of Anticoagulant

First-Line Therapy

• DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) are recommended over warfarin 1
• DOACs have been shown to be at least non-inferior and in some trials superior to warfarin for stroke prevention with lower risks of serious bleeding 1

Special Situations

• For patients with mechanical heart valves: warfarin is recommended (DOACs contraindicated) 1, 4
• For patients with moderate or severe mitral stenosis: warfarin is recommended 1

Monitoring and Follow-up

• For patients on warfarin:
  • INR should be checked at least weekly during initiation
  • Monthly when stable in therapeutic range (target INR 2.0-3.0 for AF) 1, 4
• Bleeding risk assessment should be performed at every patient contact using the HAS-BLED score 1
• High HAS-BLED score (≥3) warrants more frequent follow-up and addressing modifiable bleeding risk factors, but is not a reason to withhold anticoagulation 1

Common Pitfalls and Caveats

• Female sex alone (CHA2DS2-VASc score of 1) is not sufficient to recommend anticoagulation 1
• Even patients with a CHADS2 score of 0 may not be truly "low risk" if their CHA2DS2-VASc score is elevated 2
• The stroke risk increases dramatically with age, particularly after 65 years and even more so after 75 years 5
• Reevaluation of stroke and bleeding risks should occur periodically as these risks are dynamic 1
• Antiplatelet therapy alone is not recommended for stroke prevention in AF regardless of CHA2DS2-VASc score 1
• The pattern of AF (paroxysmal, persistent, or permanent) does not affect the recommendation for anticoagulation 1

Shared Decision Making

• Anticoagulation decisions should involve discussion of:
  • Absolute risks of stroke and bleeding
  • Patient preferences and values
  • Medication adherence considerations
  • Cost and monitoring requirements 1