What is the recommended approach to aspirin therapy for cardiovascular event prevention?

Aspirin Therapy for Cardiovascular Event Prevention

For cardiovascular disease prevention, aspirin therapy (75-162 mg/day) is strongly recommended as secondary prevention for those with established cardiovascular disease, while primary prevention should be limited to select high-risk individuals after careful consideration of bleeding risks. 1, 2

Secondary Prevention (Established Cardiovascular Disease)

Aspirin therapy is clearly beneficial for secondary prevention in patients with established cardiovascular disease:

• Dose: 75-162 mg/day 1, 2

• Indications:

  • History of atherosclerotic cardiovascular disease
  • Prior myocardial infarction
  • Prior stroke or transient ischemic attack
  • Peripheral arterial disease
  • Coronary artery bypass grafting
  • Coronary angioplasty 2

• For patients with documented aspirin allergy: Use clopidogrel 75 mg/day as an alternative 1

• For acute coronary syndrome: Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) is recommended for 12 months following the event 1, 2

Primary Prevention (No Established Cardiovascular Disease)

The approach to primary prevention is more nuanced and requires careful risk assessment:

Recommended for consideration in:

• Adults aged 40-59 years with ≥10% 10-year cardiovascular risk and no increased bleeding risk 2
• Patients with diabetes who have additional risk factors (family history of premature ASCVD, hypertension, dyslipidemia, smoking, or albuminuria) 1

Not recommended for:

• Adults over 70 years (with or without diabetes) as bleeding risks typically outweigh benefits 1, 2
• Low-risk individuals (10-year risk <6%) 1
• Patients with increased bleeding risk 1

Risk Assessment Algorithm

1. Calculate 10-year cardiovascular risk using established risk calculators

2. Assess bleeding risk factors:

   • Age >70 years
   • History of GI bleeding or ulcers
   • Concurrent use of anticoagulants or NSAIDs
   • Uncontrolled hypertension
   • Renal disease 2

3. Decision framework:

   • High CV risk (≥10%) + Low bleeding risk: Consider aspirin 75-162 mg/day
   • Moderate CV risk (6-10%) + Low bleeding risk: Individualized decision based on patient preferences
   • Low CV risk (<6%) or High bleeding risk: Aspirin generally not recommended 1, 2

Dosing Considerations

• Secondary prevention: 75-162 mg/day is effective and has better safety profile than higher doses 1
• Acute events: Loading dose of 160-325 mg followed by 75-162 mg/day maintenance 2, 3
• Primary prevention: 75-100 mg/day 2

Important Caveats

• Gastrointestinal bleeding risk increases with aspirin dose and is estimated at 2-4 per 1,000 middle-aged persons and 4-12 per 1,000 older persons given aspirin for 5 years 2
• Hemorrhagic stroke risk is estimated at 0-2 per 1,000 persons given aspirin for 5 years 2
• For primary prevention, the ASCEND trial showed that while aspirin reduced serious vascular events in patients with diabetes, it increased major bleeding, highlighting the importance of risk-benefit assessment 1
• Aspirin should be used as an adjunct to lifestyle modifications (healthy diet, smoking cessation, blood pressure control, and regular physical activity) 4

By carefully applying these guidelines and considering individual risk factors, clinicians can optimize the use of aspirin therapy to prevent cardiovascular events while minimizing bleeding risks.