What CHA2DS2-VASc (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes, Stroke or transient ischemic attack, Vascular disease, Age 65-74 years, Sex category) score warrants anticoagulation?

CHA₂DS₂-VASc Score Thresholds for Anticoagulation

Oral anticoagulation is recommended for patients with atrial fibrillation who have a CHA₂DS₂-VASc score of ≥1 in men or ≥2 in women. 1

Risk Stratification Based on CHA₂DS₂-VASc Score

The CHA₂DS₂-VASc score is a validated tool for assessing stroke risk in patients with atrial fibrillation, with points assigned as follows:

• Congestive heart failure/LV dysfunction: 1 point
• Hypertension: 1 point
• Age ≥75 years: 2 points
• Diabetes mellitus: 1 point
• Stroke/TIA/thromboembolism (previous): 2 points
• Vascular disease (prior MI, PAD, aortic plaque): 1 point
• Age 65-74 years: 1 point
• Sex category (female): 1 point

Anticoagulation Recommendations by Score

1. CHA₂DS₂-VASc score = 0 (men) or 1 (women):

   • No anticoagulation required 1
   • Truly low risk with stroke rates of approximately 0.49 per 100 person-years 2

2. CHA₂DS₂-VASc score = 1 (men) or 2 (women):

   • Oral anticoagulation recommended 1
   • Significant increase in stroke risk (3.01-fold higher at 1 year) compared to lower scores 2
   • Annual stroke rates range from 1.91% to 3.50% depending on the specific risk factor 3

3. CHA₂DS₂-VASc score ≥2 (men) or ≥3 (women):

   • Definite indication for oral anticoagulation 1
   • High risk of stroke with rates increasing substantially with each point increase 4

Important Clinical Considerations

Risk Factor Variability

Not all risk factors in the CHA₂DS₂-VASc score carry equal weight:

• Age 65-74 years is associated with the highest stroke rate (3.50%/year in men, 3.34%/year in women) 3
• Vascular disease confers the lowest additional risk (1.96%/year in men) 3

Bleeding Risk Assessment

• Use the HAS-BLED score to identify modifiable bleeding risks
• A high HAS-BLED score (≥3) indicates increased bleeding risk but should not automatically contraindicate anticoagulation 1
• Instead, high bleeding risk should prompt:
  • Closer monitoring
  • Correction of modifiable risk factors
  • More frequent follow-up 1

Anticoagulant Selection

• Direct oral anticoagulants (DOACs) are preferred over warfarin for most patients due to:
  • No need for regular INR monitoring
  • Fewer food and drug interactions
  • Lower risk of intracranial hemorrhage
  • At least equivalent efficacy for stroke prevention 1

Common Pitfalls to Avoid

1. Using aspirin instead of anticoagulation: Aspirin monotherapy is not recommended for stroke prevention in atrial fibrillation regardless of stroke risk 1

2. Overemphasizing bleeding risk: A high bleeding risk score should lead to closer monitoring and addressing modifiable risk factors, not withholding anticoagulation 1

3. Failing to reassess risk over time: The CHA₂DS₂-VASc score should be periodically reassessed as risk factors may develop over time 1

4. Misclassifying low-risk patients: Using only the older CHADS₂ score may misclassify patients, particularly women and those aged 65-74 years, who would benefit from anticoagulation 5, 4

The evidence clearly supports that even patients with a single additional stroke risk factor beyond sex have a significantly elevated stroke risk that warrants anticoagulation, with the benefits outweighing the bleeding risks in most cases 2, 3.