What is the recommended dose of aspirin (acetylsalicylic acid) for an adult patient with a history of cerebrovascular accident (CVA) for the prevention of further cardiovascular events?

Aspirin Dosing for Secondary Prevention After Cerebrovascular Accident

For adults with a history of CVA, aspirin 75-100 mg daily is recommended for lifelong secondary prevention. 1

Recommended Dosing Regimen

The optimal dose is 75-100 mg aspirin once daily, taken indefinitely after the initial stroke event. 1, 2 This low-dose range provides maximal cardiovascular protection while minimizing bleeding complications compared to higher doses. 1

• The most common formulation in the United States is 81 mg daily, which falls within the recommended therapeutic range. 1, 2
• Daily doses of 75-100 mg are as effective as higher doses (up to 1300 mg) for long-term stroke prevention. 1, 3
• Higher maintenance doses (300-325 mg daily) offer no additional benefit and significantly increase bleeding risk. 4

Evidence Supporting Low-Dose Aspirin

The 2024 European Society of Cardiology guidelines provide the strongest and most recent evidence, recommending aspirin 75-100 mg daily for patients with prior stroke as Class I, Level A evidence. 1 This recommendation is based on individual-patient data meta-analysis of secondary prevention trials involving 43,000 patient-years, which demonstrated that aspirin significantly reduced the combined risk of non-fatal MI, non-fatal ischemic stroke, or vascular death from 8.2% to 6.7% per year. 1

• Aspirin reduces total stroke by approximately one-fifth (from 2.54% to 2.08% per year) in secondary prevention. 1
• The relative risk reductions are 31% for MI, 22% for stroke, and 9% for vascular death. 1
• These benefits translate to 15 fewer fatal and non-fatal serious vascular events for every 1,000 patients treated for 1 year. 1

Bleeding Risk Considerations

While aspirin increases major gastrointestinal and extracranial bleeding from 0.07% to 0.10% per year, the reduction in ischemic events substantially outweighs these bleeding risks in secondary prevention. 1

• Major bleeding events occur at approximately 5 per 1,000 per year in real-world settings. 1
• Lower doses (75-100 mg) significantly reduce gastrointestinal bleeding and epigastric pain compared to higher doses while maintaining equivalent efficacy. 5, 3
• There is no significant increase in hemorrhagic stroke with low-dose aspirin in secondary prevention. 1

Alternative Antiplatelet Therapy

For patients with documented aspirin allergy or intolerance, clopidogrel 75 mg daily is recommended as the alternative antiplatelet agent. 1, 2

• Clopidogrel provides equivalent cardiovascular protection to aspirin in secondary prevention. 1
• This substitution is supported by Class I, Level A evidence from the 2024 ESC guidelines. 1

Critical Clinical Pitfalls to Avoid

Do not use higher aspirin doses (>100 mg daily) for long-term secondary prevention, as they increase bleeding without improving efficacy. 1, 4, 3 The mechanistic studies and randomized clinical trials demonstrate that the antithrombotic effect of aspirin in cerebrovascular disease requires the same dose as for ischemic heart disease. 6

Avoid concurrent NSAIDs in patients on aspirin therapy. 4 NSAIDs are associated with increased major adverse cardiovascular events in patients with prior cardiovascular disease and should be replaced with acetaminophen or short-acting opioids when pain management is needed. 4

Do not discontinue aspirin in patients with established cerebrovascular disease unless there is active bleeding or another absolute contraindication. 1 For secondary prevention, the benefits far exceed the risks, and aspirin remains strongly recommended. 1

Dual Antiplatelet Therapy Considerations

If the CVA occurred in the context of acute coronary syndrome, dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) is reasonable for 12 months, after which aspirin monotherapy should be continued lifelong. 1, 2

• After the initial DAPT period following acute events or revascularization, transition to aspirin 75-100 mg daily monotherapy. 1
• Extended dual antiplatelet therapy beyond 12 months may have benefits in selected high-risk patients with low bleeding risk. 1