Has the patient experienced an ischemic stroke before age 50, and should his/her siblings receive low‑dose aspirin for primary prevention?

Aspirin for Siblings of Young Stroke Patients

Siblings of patients who experienced ischemic stroke before age 50 should NOT routinely receive aspirin for primary prevention unless they have established cardiovascular disease or meet specific high-risk criteria with 10-year cardiovascular disease risk ≥10%. 1

Current Evidence Against Routine Aspirin for Primary Prevention

The most recent 2024 AHA/ASA stroke prevention guidelines fundamentally changed recommendations for aspirin in primary prevention:

• In patients with common vascular risk factors and no prior stroke, aspirin use to prevent a first stroke is not well established (Class 2b recommendation, Level A evidence). 1

• In individuals ≥70 years of age with cardiovascular risk factors, aspirin is NOT beneficial to prevent a first stroke (Class 3: No Benefit, Level A evidence). 1

• In patients with chronic kidney disease, aspirin is NOT effective to prevent a first stroke (Class 3: No Benefit, Level B-NR evidence). 1

Why the Recommendation Changed

Recent large trials demonstrated that aspirin's bleeding risks outweigh stroke prevention benefits in most primary prevention scenarios:

• The ASPREE trial (median age 74 years, 4.7 years follow-up) showed no reduction in stroke with aspirin 100 mg daily, but found a significant 0.7% absolute increase in intracranial bleeding. 1

• A 2023 secondary analysis of ASPREE specifically examining stroke outcomes confirmed aspirin did not produce statistically significant reduction in ischemic stroke (HR 0.89; 95% CI 0.71-1.11), but significantly increased intracranial bleeding (HR 1.38; 95% CI 1.03-1.84). 2

• The JPPP trial in Japanese patients (mean age 71 years) similarly found no stroke reduction with aspirin. 1

When Aspirin MAY Be Considered for Siblings

Aspirin might be reasonable only if the sibling has:

• Established cardiovascular disease (prior MI, known coronary artery disease, peripheral artery disease) - in which case aspirin is for secondary prevention, not primary prevention. 1

• 10-year cardiovascular disease risk ≥10% based on validated risk calculators (ACC/AHA risk calculator), AND age 50-59 years, AND willingness to take aspirin long-term (≥10 years for colorectal cancer benefit). 1

• Diabetes with additional major risk factors (though even this indication has become controversial after recent trials). 1

Risk Assessment Framework

Calculate 10-year cardiovascular disease risk using the ACC/AHA risk calculator incorporating: 1

• Age, sex, race/ethnicity
• Total and HDL cholesterol
• Systolic blood pressure and treatment status
• Diabetes status
• Smoking status

The threshold for considering aspirin is 10-year CVD risk ≥10%, and even then, the benefit is modest and must be weighed against bleeding risk. 1

Bleeding Risk Factors to Assess

Before considering aspirin, evaluate for contraindications: 1

• History of gastrointestinal ulcers or upper GI bleeding
• Bleeding disorders or thrombocytopenia
• Uncontrolled hypertension (increases both stroke AND bleeding risk)
• Concurrent anticoagulation or NSAID use
• Renal failure or severe liver disease
• Age ≥70 years (bleeding risk exceeds benefit)

Family History Context

While having a sibling with stroke under age 50 suggests possible familial predisposition, this alone does NOT justify aspirin therapy. 1 Instead, siblings should undergo: 1

• Comprehensive cardiovascular risk factor assessment
• Screening for modifiable risk factors (hypertension, diabetes, dyslipidemia, smoking)
• Consideration of genetic or familial conditions (familial hypercholesterolemia, hypercoagulable states)
• Aggressive management of identified risk factors through lifestyle modification and appropriate pharmacotherapy (statins for dyslipidemia, antihypertensives for hypertension)

Common Pitfalls to Avoid

• Do not prescribe aspirin based solely on family history without formal cardiovascular risk assessment. 1

• Do not assume aspirin is "harmless" - the bleeding risk is real and increases with age. 2

• Do not use aspirin as a substitute for addressing modifiable risk factors like hypertension, smoking, or dyslipidemia. 1

• Do not continue outdated primary prevention practices - the evidence base has fundamentally shifted against routine aspirin for primary stroke prevention. 1

Alternative Prevention Strategies

For siblings of young stroke patients, focus on: 1

• Statin therapy if LDL cholesterol is elevated or 10-year ASCVD risk is ≥7.5%
• Blood pressure control targeting <130/80 mmHg
• Smoking cessation if applicable
• Diabetes management if present
• Lifestyle modification (diet, exercise, weight management)

These interventions have stronger evidence for stroke prevention than aspirin in the primary prevention setting. 1