Is thrombolysis contraindicated in a patient who received 300mg of aspirin (acetylsalicylic acid) 1.5 hours prior?

Thrombolysis After Recent Aspirin Administration

Direct Answer

Thrombolysis is NOT absolutely contraindicated in an aspirin-naive person who received aspirin 300mg 1.5 hours previously, but it significantly increases the risk of symptomatic intracranial hemorrhage and requires careful risk-benefit assessment. 1, 2

Context-Specific Recommendations

For Acute Ischemic Stroke

If this is for stroke thrombolysis, you should strongly consider withholding IV alteplase and pursuing mechanical thrombectomy instead, as aspirin 300mg given shortly before thrombolysis is not a contraindication for mechanical thrombectomy but does increase bleeding risk with IV thrombolysis. 1

• The American Heart Association/American Stroke Association explicitly recommends that aspirin should not be administered within 24 hours before or concurrently with thrombolytic therapy, as this significantly increases symptomatic intracranial hemorrhage risk. 1

• However, the absolute excess risk of symptomatic intracranial hemorrhage with aspirin pretreatment is approximately 1.4%, which must be weighed against the substantial mortality benefit of thrombolysis (18-50% reduction). 1

If you proceed with thrombolysis despite recent aspirin:

• Monitor the patient extremely closely for neurological deterioration in the first 24 hours. 1
• Obtain brain imaging at 24 hours to exclude intracranial hemorrhage before any additional antiplatelet therapy. 1, 3
• Hold all antiplatelet agents until after the 24-hour scan confirms no hemorrhage. 1, 2

For ST-Elevation Myocardial Infarction (STEMI)

If this is for STEMI, aspirin administration at the time of fibrinolysis is actually mandatory and standard of care. 1

• The European Heart Society notes that aspirin must be given with fibrinolysis for STEMI management. 1
• Additional treatment with aspirin and heparin is recommended to prevent rethrombosis after cardiac thrombolysis. 4
• In the cardiac context, aspirin pretreatment is expected and does not contraindicate thrombolysis. 5, 4

Critical Timing Algorithm

For stroke patients specifically:

1. If aspirin was given <24 hours before planned thrombolysis: Consider mechanical thrombectomy as the primary intervention rather than IV thrombolysis. 1

2. If thrombolysis is still being considered: Weigh the 1.4% absolute increase in symptomatic intracranial hemorrhage against the 18-50% mortality reduction from thrombolysis. 1

3. If thrombolysis is administered: Implement enhanced monitoring protocols and mandatory 24-hour imaging before any further antiplatelet therapy. 1, 2

Common Pitfalls to Avoid

• Do not automatically exclude stroke patients from thrombolysis solely based on recent aspirin use - this is a relative, not absolute, contraindication that requires individualized risk-benefit analysis. 1

• Do not confuse stroke and cardiac thrombolysis protocols - aspirin is contraindicated before stroke thrombolysis but mandatory for cardiac thrombolysis. 1

• Do not restart aspirin immediately after stroke thrombolysis - wait the full 24 hours and confirm no hemorrhage on imaging first. 1, 2, 3

• Do not use aspirin as a substitute for acute stroke interventions including IV thrombolysis or mechanical thrombectomy (Class III recommendation). 3