What are the recommendations for aspirin (acetylsalicylic acid) therapy in patients at high risk of cardiovascular events?

Aspirin Recommendations for Cardiovascular Disease Prevention

For patients at high risk of cardiovascular events, aspirin therapy is most beneficial for secondary prevention in those with established cardiovascular disease (75-100 mg daily), while it is generally not recommended for primary prevention, particularly in adults aged 60 years or older, due to bleeding risks outweighing cardiovascular benefits. 1

Patient Risk Stratification

Secondary Prevention (Established CVD)

• Aspirin therapy is strongly recommended for patients with established cardiovascular disease 1
• Dosing recommendations:
  • Initial loading dose of 160-325 mg for acute MI
  • Maintenance dose of 75-100 mg daily for long-term prevention 1
• Alternative: Clopidogrel 75 mg daily if aspirin is contraindicated 1
• Benefits in secondary prevention:
  • Reduces risk of serious vascular events by approximately 25% 1, 2
  • Reduces risk of coronary heart disease by 28% 1
  • Reduces nonfatal MI by 26% 1
  • Reduces stroke by 25% 1
  • Reduces all-cause mortality by 13% 1

Primary Prevention (No Established CVD)

Risk Assessment

• Calculate 10-year ASCVD risk using a validated calculator before considering aspirin therapy 1
• High risk defined as ≥10% 10-year risk 1
• Assess bleeding risk factors:
  • Age >70 years
  • History of GI bleeding/ulcers
  • Concurrent anticoagulant or NSAID use
  • Uncontrolled hypertension
  • Renal disease
  • Anemia
  • Thrombocytopenia
  • Coagulopathy
  • Chronic kidney disease 1

Recommendations by Age and Risk

1. Ages 40-59 with ≥10% 10-year ASCVD risk and low bleeding risk:

   • Consider low-dose aspirin (75-162 mg daily) 1, 3
   • Benefits include modest reduction in non-fatal MI 1

2. Ages 40-59 with <10% 10-year ASCVD risk:

   • Aspirin NOT recommended 1

3. Ages ≥60 years (any risk level):

   • Aspirin NOT recommended due to increased bleeding risks outweighing cardiovascular benefits 1, 3

4. Any age with high bleeding risk:

   • Aspirin NOT recommended 1

Contraindications and Precautions

Absolute Contraindications

• Active peptic ulcer disease
• History of aspirin allergy
• Severe liver disease
• Bleeding disorders
• Age under 21 years (risk of Reye syndrome) 1

Relative Contraindications

• History of GI bleeding/ulcers
• Age >70 years
• Concurrent anticoagulant or NSAID use
• Uncontrolled hypertension 1

Monitoring and Safety

• Monitor for signs of bleeding while on aspirin therapy 1
• Major bleeding risk increases by 29-48% with aspirin therapy 1
• Major GI bleeding occurs in 2-4 per 1,000 middle-aged individuals and 4-12 per 1,000 older individuals over 5 years 1
• Hemorrhagic stroke risk increases by 0-2 per 1,000 persons over 5 years 1

Common Pitfalls to Avoid

• Initiating aspirin for primary prevention without calculating ASCVD risk
• Using aspirin in patients aged ≥60 years for primary prevention
• Prescribing higher than necessary doses (>100 mg daily for most indications)
• Failing to assess bleeding risk before recommending aspirin
• Using aspirin as an alternative rather than an adjunct to managing other cardiovascular risk factors 1, 2

Special Populations

• Diabetes mellitus: May be considered in patients over 50 years with at least one additional major risk factor and no increased bleeding risk 1
• The clinical consequences of increased bleeding risk may outweigh the modest benefits in primary prevention, even in higher-risk populations 4, 5