Aspirin for Malignant Infarct
Aspirin should be administered within 24-48 hours of stroke onset in patients with malignant infarct, but only after neuroimaging excludes hemorrhage and only if thrombolytic therapy was not used or has been completed with a 24-hour safety window. 1, 2
Critical Timing Considerations
The management of aspirin in malignant infarct depends entirely on whether thrombolytic therapy was administered:
For Patients Who Received Thrombolysis (tPA)
- Delay aspirin for 24 hours post-thrombolysis and only initiate after repeat neuroimaging excludes intracranial hemorrhage 2, 3
- Aspirin as adjunctive therapy within 24 hours of thrombolytic administration is explicitly not recommended due to increased bleeding risk 1
- After the 24-hour safety window and negative imaging, initiate aspirin 160-325 mg daily 2, 3
For Patients Who Did Not Receive Thrombolysis
- Initiate aspirin 160-325 mg immediately after CT/MRI excludes hemorrhage, ideally within 24-48 hours of symptom onset 1
- This applies even to large "malignant" infarcts, as the absolute benefit of preventing recurrent ischemic stroke (7 per 1000 patients) outweighs the small increased risk of hemorrhagic transformation (2 per 1000 patients) 1, 4
Evidence Supporting Early Aspirin Use
The recommendation is based on two landmark trials involving 40,000 patients with acute ischemic stroke:
- Recurrent stroke reduction: Aspirin reduces recurrent ischemic stroke by approximately 7 per 1000 patients within the first month 1, 4
- Mortality benefit: Reduces death without further stroke by 4 per 1000 patients 1, 4
- Net benefit: Overall reduction of 9 per 1000 in further stroke or death despite a small increase (2 per 1000) in hemorrhagic transformation 1, 4
Critical Pitfalls to Avoid
Do not withhold aspirin based on infarct size alone. The proportional benefit of aspirin does not differ significantly based on stroke severity, age, blood pressure, or stroke subtype 4. Even among 9,000 patients randomized without prior CT scan, aspirin showed net benefit with no unusual excess of hemorrhagic stroke 4.
The hemorrhagic transformation risk is real but small. While aspirin increases hemorrhagic transformation by 0.1% absolute risk, this is vastly outweighed by the 30% proportional reduction in recurrent ischemic events 1.
Optimal Dosing
- Initial dose: 160-325 mg loading dose 1, 2, 3
- Maintenance: 75-160 mg daily for long-term secondary prevention 1
- Higher doses (>325 mg) provide no additional benefit and may increase bleeding complications 1, 5
Special Consideration for Malignant Infarcts
Malignant infarcts carry high risk of both cerebral edema and recurrent thrombotic events. Aspirin does not substitute for other acute interventions such as decompressive hemicraniectomy if indicated, but should be part of the comprehensive management strategy 1. The antiplatelet benefit for preventing early recurrence remains critical even in large infarcts, as the 28-day recurrent stroke rate without aspirin approaches 2.3% 4.
Contraindications
Absolute contraindications include active hemorrhage, known hypersensitivity, bleeding peptic ulcer, blood dyscrasia, or severe hepatic disease 1. Aspirin may trigger bronchospasm in asthmatics but this is rare 1.