Is aspirin (acetylsalicylic acid) recommended for a patient with a CHA2DS2-VASc (Cardiac failure, Hypertension, Age ≥ 75 years, Diabetes, Stroke or transient ischemic attack, Vascular disease, Age 65-74 years, Sex category) score of 0?

Aspirin is Not Recommended for Patients with CHA2DS2-VASc Score of 0

In patients with a CHA2DS2-VASc score of 0, aspirin should not be used for stroke prevention as it offers no benefit but increases bleeding risk. 1

Evidence-Based Rationale

Risk Assessment for CHA2DS2-VASc Score of 0

• A CHA2DS2-VASc score of 0 represents a truly low-risk population with annual stroke rates of:
  • 0.49-0.84 events per 100 person-years 2, 3
  • This is below the threshold of 1% annual stroke risk generally considered necessary to justify antithrombotic therapy

Current Guideline Recommendations

The 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society Guidelines explicitly state:

• For patients with nonvalvular AF and a CHA2DS2-VASc score of 0, it is reasonable to omit antithrombotic therapy (Class IIa recommendation, Level of Evidence B) 1
• Neither oral anticoagulation nor aspirin should be prescribed in this low-risk population 1

Bleeding Risk vs. Benefit

• Aspirin therapy in low-risk patients:
  • Does not reduce stroke risk compared to no therapy 4
  • Significantly increases bleeding complications:
    • GI bleeding (1.9% vs 1.1% with no therapy) 4
    • GU bleeding (2.8% vs 2.1% with no therapy) 4

Clinical Application

Determining True Low Risk

To ensure a patient truly has a CHA2DS2-VASc score of 0:

• Confirm absence of ALL risk factors:
  • No congestive heart failure
  • No hypertension
  • Age < 65 years
  • No diabetes mellitus
  • No prior stroke/TIA
  • No vascular disease
  • Male sex (females automatically score 1 point)

Common Pitfalls to Avoid

1. Misclassification of risk: Ensure all risk factors are properly assessed. Some patients classified as "low risk" by older scoring systems (like CHADS2) may actually have risk factors captured by CHA2DS2-VASc.

2. Automatic aspirin prescription: There is a common misconception that aspirin is a "safer" alternative for low-risk patients. Evidence shows this is not the case - it increases bleeding without providing stroke protection.

3. Overlooking vascular disease: Patients with coronary, aortic, or peripheral arterial disease automatically have at least 1 point on the CHA2DS2-VASc score.

4. Female sex consideration: Women automatically receive 1 point, so a truly low-risk female patient would need to have no other risk factors to have a CHA2DS2-VASc score of 1 (which is considered equivalent to a score of 0 for treatment purposes).

Monitoring and Reassessment

• Reevaluate stroke risk periodically (at least annually) as patients may develop new risk factors over time
• If a patient develops even one risk factor (CHA2DS2-VASc score becomes 1 for men or 2 for women), reconsider antithrombotic therapy options

In conclusion, for patients with atrial fibrillation and a CHA2DS2-VASc score of 0, aspirin provides no benefit for stroke prevention while increasing bleeding risk, and therefore should not be prescribed.