Is aspirin (acetylsalicylic acid) indicated in the management of a patient with ischemic stroke?

Aspirin in Ischemic Stroke: Definitive Recommendations

Yes, aspirin should be administered in acute ischemic stroke at a dose of 160-325 mg within 24-48 hours of symptom onset, after brain imaging has excluded hemorrhage. 1, 2

Timing and Dosing Algorithm

Step 1: Obtain brain imaging immediately to confirm ischemic stroke and exclude intracranial hemorrhage before any aspirin administration. 2, 3, 4

Step 2: Determine thrombolytic eligibility. If the patient receives IV rtPA, aspirin is absolutely contraindicated for 24 hours due to significantly increased risk of serious intracranial bleeding. 1, 2, 3

Step 3: Administer aspirin 160-325 mg within 24-48 hours if no contraindications exist. 1, 2, 3

Evidence Base and Outcomes

The primary benefit of early aspirin is reduction of early recurrent ischemic stroke, not limitation of the initial stroke's neurological consequences. 1, 2 The evidence demonstrates:

• Prevents approximately 7 recurrent ischemic strokes per 1,000 patients during the acute treatment period. 3, 5
• Reduces mortality by approximately 4 deaths per 1,000 patients during the 28-day treatment period. 3, 6, 5
• Small increase in hemorrhagic transformation of approximately 2 per 1,000 patients, which does not offset the ischemic stroke reduction benefit. 3, 5
• Net benefit of 9 fewer strokes or deaths per 1,000 patients treated. 5

This recommendation carries Class I, Level of Evidence A rating from the American Heart Association/American Stroke Association, representing the highest quality evidence. 1, 2

Critical Contraindications (Absolute)

• Within 24 hours of IV thrombolysis - this is the most common and dangerous pitfall in clinical practice. 1, 2, 3
• Confirmed intracranial hemorrhage on imaging. 4
• Aspirin allergy or active gastrointestinal bleeding. 2

Subgroup Considerations

The benefit of aspirin is remarkably consistent across patient subgroups. Analysis of 40,000 patients demonstrates no significant heterogeneity in the proportional benefit regardless of: 5

• Age (including elderly patients) 5
• Stroke severity (NIHSS score) 5
• Presence of atrial fibrillation 5
• Blood pressure level 5
• Stroke subtype 5
• Level of consciousness 5

Even among 9,000 patients randomized without prior CT scan, aspirin showed net benefit with no unusual excess of hemorrhagic stroke. 5

What Aspirin Is NOT

Aspirin is not a substitute for IV rtPA in eligible patients - it does not provide acute recanalization and should never delay or replace thrombolytic therapy. 1, 2, 3

Aspirin is not a neuroprotective agent - it does not limit the neurological damage from the initial stroke, only prevents recurrence. 1

Alternative Antiplatelet Agents

Clopidogrel alone or in combination with aspirin is not recommended for routine acute ischemic stroke treatment (Class III recommendation). 1, 2 The usefulness of clopidogrel in acute stroke remains not well established (Class IIb, Level of Evidence C). 1, 2

Intravenous glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban) are not recommended outside clinical trials due to unproven efficacy and safety concerns. 1, 2

Common Pitfalls to Avoid

1. Administering aspirin before brain imaging - hemorrhage must be excluded first. 4
2. Giving aspirin within 24 hours of thrombolysis - this dramatically increases bleeding risk. 1, 2, 3
3. Using aspirin as a substitute for rtPA - aspirin does not provide recanalization. 1, 3
4. Delaying aspirin beyond 48 hours without contraindications - early administration is when benefit is demonstrated. 3, 6
5. Using dual antiplatelet therapy acutely in large strokes - bleeding risk outweighs benefit in the acute setting. 3