Timing of Aspirin After Thrombectomy for Acute Ischemic Stroke
Wait 24 hours after thrombectomy before starting aspirin, with brain imaging to exclude intracranial hemorrhage before initiation.
Standard Guideline-Based Approach
The timing of aspirin after thrombectomy depends critically on whether the patient received IV thrombolysis (tPA):
For Patients Who Received IV Thrombolysis + Thrombectomy
- Delay aspirin for 24 hours after tPA administration 1, 2, 3
- Obtain a 24-hour post-thrombolysis CT scan to exclude intracranial hemorrhage before starting aspirin 1, 2
- After the 24-hour scan confirms no hemorrhage, initiate aspirin 160-325 mg 2, 3
- This delay is critical because combining aspirin with thrombolytic agents significantly increases symptomatic intracranial hemorrhage risk 2, 4
For Patients Who Had Thrombectomy Alone (No IV tPA)
- Start aspirin immediately after thrombectomy once brain imaging excludes hemorrhage 1, 3
- Administer a loading dose of at least 160 mg aspirin 1, 3
- No 24-hour waiting period is required when IV thrombolysis was not used 1
Evidence Quality and Nuances
The guideline recommendations are based on Level A and B evidence from major stroke trials. The Canadian Stroke Best Practice guidelines explicitly state that in tPA clinical trials, antithrombotic drugs were systematically avoided until after 24-hour imaging excluded hemorrhage 1. The American Heart Association and American Stroke Association consistently reinforce this 24-hour delay to minimize bleeding complications 2.
A critical caveat exists for emergency stenting during thrombectomy: When acute carotid or intracranial stenting is required during the thrombectomy procedure (for tandem occlusions or underlying atherosclerotic disease), earlier antiplatelet administration may be necessary to prevent stent thrombosis 5, 6. In these select cases, aspirin has been administered as early as 3-7 hours post-tPA without increased symptomatic hemorrhage rates 5, 6. However, this represents an exception requiring specialized neurointerventional judgment, not standard practice 5.
Common Pitfalls to Avoid
- Do not give aspirin concurrently with or immediately after IV thrombolysis - this substantially increases symptomatic intracranial hemorrhage risk 2, 4
- Do not use enteric-coated aspirin acutely - non-enteric coated formulations provide faster absorption when rapid platelet inhibition is needed 3
- Do not skip the 24-hour post-thrombolysis imaging - hemorrhage must be excluded before starting any antiplatelet therapy 1, 2
- Do not delay aspirin beyond 48 hours in confirmed ischemic stroke (when no tPA was given) - early administration provides maximum benefit 3, 7
Maintenance Therapy
After the initial loading dose, continue aspirin 81-325 mg daily indefinitely for secondary stroke prevention 1, 3, 7. For patients with dysphagia, alternative routes include enteral tube (80 mg daily) or rectal suppository (325 mg daily) 1, 3.