CHA₂DS₂-VASc Score Calculation
The correct answer is C. 3 points.
Score Breakdown
For this 71-year-old male with a history of stroke and no other comorbidities, the CHA₂DS₂-VASc score is calculated as follows:
- Age 65-74 years: 1 point 1
- Prior stroke: 2 points 1
- Male sex: 0 points 1
- All other components (congestive heart failure, hypertension, diabetes, vascular disease): 0 points 1
Total score: 3 points 1
Important Clarification on Age Scoring
A critical distinction exists between the older CHADS₂ and newer CHA₂DS₂-VASc scoring systems regarding age:
- CHADS₂ score: Awards 1 point only for age ≥75 years 2
- CHA₂DS₂-VASc score: Awards 1 point for age 65-74 years AND 2 points for age ≥75 years 3, 1
Since this patient is 71 years old, he receives 1 point for age under CHA₂DS₂-VASc (not 0 points as would be the case with CHADS₂) 1.
Clinical Significance
A CHA₂DS₂-VASc score of 3 indicates high stroke risk, with an annual stroke rate of approximately 3.2-5.3% without anticoagulation 3. This score mandates oral anticoagulation therapy 3.
Anticoagulation Recommendation
- Oral anticoagulation is strongly recommended (Class I indication) for any patient with CHA₂DS₂-VASc score ≥2 3, 1
- Direct oral anticoagulants (DOACs) are preferred over warfarin as first-line therapy 1
- If warfarin is used, maintain INR 2.0-3.0 with time in therapeutic range >70% 1
Common Pitfall
The most frequent error in this scenario is misapplying CHADS₂ age criteria to CHA₂DS₂-VASc scoring 2. Clinicians may incorrectly assign 0 points for age <75 years, yielding an incorrect total of 2 points instead of 3 points 2. This distinction is clinically meaningful because it affects risk stratification and reinforces the indication for anticoagulation 3.