Aspirin Recommendations for High ASCVD Risk
For individuals at high risk of atherosclerotic cardiovascular disease (≥10% 10-year risk), aspirin 75-100 mg daily is recommended for primary prevention, with the understanding that net benefit increases as ASCVD risk increases, generally exceeding bleeding risks at ≥10% 10-year risk. 1
Dosing Recommendations
For Established ASCVD (Secondary Prevention)
- Loading dose: 162-325 mg orally (chewed when possible for faster onset) 1
- Maintenance dose: 75-100 mg daily (uncoated formulation preferred) 1
- This dosing exceeds the minimal effective dose for platelet thromboxane A₂ suppression while allowing for interindividual variability 1
- Higher maintenance doses (300-325 mg daily) offer no additional benefit and increase bleeding risk 1
For Primary Prevention in High-Risk Patients
- Daily dose: 75-162 mg for patients with ≥10% 10-year ASCVD risk 1
- The 75-100 mg range is preferred as it provides equivalent efficacy with lower bleeding rates compared to higher doses 1
- For patients with diabetes and established ASCVD, use 75-162 mg daily 1
Risk Stratification for Primary Prevention
High-risk criteria warranting aspirin consideration include: 1
- 10-year ASCVD risk ≥10% (some guidelines suggest ≥20% for strongest benefit) 1
- Men ≥50 years or women with diabetes plus ≥1 additional major risk factor (family history of premature ASCVD, hypertension, dyslipidemia, smoking, chronic kidney disease/albuminuria) 1
- Established coronary, cerebrovascular, or peripheral arterial disease 1
Important age consideration: For patients >70 years without established ASCVD, bleeding risk generally outweighs benefit, and aspirin is not recommended for primary prevention 1, 2
Benefit-Risk Balance
The absolute benefits substantially outweigh bleeding risks in moderate-to-high risk settings (≥3% annual vascular event rate, equivalent to ≥10% 10-year risk) 1, 3
- In established ASCVD, aspirin prevents approximately 25% of serious vascular events 5
- Net ASCVD benefit and bleeding risk both increase with baseline ASCVD risk, but benefits generally exceed risks at ≥10% 10-year risk 3
- The excess bleeding risk may be as high as 5 per 1,000 per year, but for adults with ASCVD risk >1% per year, events prevented typically equal or exceed bleeding episodes induced 1
Contraindications and Alternatives
Absolute contraindications include: 1
- Documented aspirin allergy or hypersensitivity
- Active bleeding or high bleeding risk (older age, anemia, renal disease)
- Recent gastrointestinal bleeding
- Clinically active hepatic disease
For aspirin-intolerant patients: 1
- Clopidogrel 75 mg daily is the recommended alternative for secondary prevention 1
- Aspirin desensitization is preferred when possible to allow dual antiplatelet therapy 1
Critical Pitfalls to Avoid
Do not use NSAIDs for pain management in patients on aspirin: 1, 6
- NSAIDs are associated with increased MACE risk in patients with and without prior cardiac disease 1
- If NSAIDs are unavoidable, do not discontinue low-dose aspirin, though this amplifies GI bleeding risk 1
- Consider acetaminophen or short-acting opioids as alternatives 6
Do not use enteric-coated formulations for loading doses: 1
- Uncoated aspirin should be chewed for acute presentations to achieve faster antiplatelet action 1
Do not continue high-dose aspirin long-term: 1
- After initial loading in ACS, transition to 75-100 mg daily rather than continuing 300-325 mg 1
Special Populations
Patients on ticagrelor: Aspirin doses ≤100 mg daily should always be used 1
Patients requiring anticoagulation: After 1-4 weeks post-PCI, aspirin discontinuation is appropriate while continuing P2Y12 inhibitor with full-dose anticoagulant 1
Patients with elevated Lp(a) >50 mg/dL: Emerging evidence suggests approximately 50% reduction in coronary events with aspirin use, though shared decision-making regarding bleeding risk is essential 7