Do you administer aspirin (acetylsalicylic acid) loading prior to acute thrombectomy for M1 (middle cerebral artery) occlusion?

Aspirin Loading Prior to Acute Thrombectomy for M1 Occlusion

Do not routinely administer aspirin loading prior to acute thrombectomy for M1 occlusion in patients who are candidates for or have received intravenous thrombolysis, as antiplatelet agents should be avoided until after the 24-hour post-thrombolysis scan has excluded intracranial hemorrhage. 1

Clinical Decision Algorithm

For Patients Receiving or Eligible for IV Thrombolysis

• Withhold aspirin loading before and during the thrombectomy procedure if the patient has received or will receive IV tPA 1
• Delay aspirin administration until after the 24-hour post-thrombolysis CT scan confirms absence of intracranial hemorrhage 1
• After hemorrhage is excluded, administer aspirin 160-325 mg as a loading dose, followed by 75-100 mg daily maintenance 1

For Patients NOT Receiving IV Thrombolysis

• Aspirin may be administered if emergent carotid stenting is required during the thrombectomy procedure 2, 3
• Intravenous aspirin 250-500 mg can be given intraoperatively when stenting is performed, even in the acute thrombectomy setting 2, 3
• Recent evidence demonstrates that intraprocedural IV aspirin during emergent stenting does not increase symptomatic intracranial hemorrhage rates (4% with aspirin vs 17% without, p=NS) and is associated with greater NIHSS improvement 2

Evidence Supporting This Approach

Stroke-Specific Guidelines vs. Cardiac Guidelines

The provided cardiac guidelines 1 address aspirin loading for acute coronary syndromes, not acute ischemic stroke with thrombectomy. These cardiac recommendations do not apply to the stroke thrombectomy population and should not guide decision-making in this context.

Stroke-Specific Evidence

• Canadian stroke guidelines explicitly state that aspirin should be delayed until 24 hours post-thrombolysis to avoid hemorrhagic complications 1
• For acute stroke patients not receiving thrombolysis, aspirin 160 mg should be given immediately after brain imaging excludes hemorrhage and dysphagia screening is passed 1
• In the specific context of emergent stenting during thrombectomy, intraprocedural aspirin (even combined with thrombolysis) showed greater NIHSS improvement (median 12 points vs 7 points, p=0.01) and lower mortality (12% vs 40%, p=0.05) without increased bleeding 2

Pre-Stroke Aspirin Use

• Patients already on low-dose aspirin (75-100 mg) prior to stroke who undergo thrombectomy for distal medium vessel occlusions demonstrate better functional outcomes (OR=1.89 for mRS 0-2) and lower mortality (OR=0.56) without increased symptomatic ICH 4
• This suggests that chronic aspirin use does not contraindicate thrombectomy, but does not support acute loading in the peri-procedural period

Critical Safety Considerations

Hemorrhagic Risk

• The primary concern with aspirin loading before or during thrombectomy is the risk of symptomatic intracranial hemorrhage, particularly when combined with thrombolysis 1
• However, when aspirin is required for emergent stenting, the hemorrhagic risk appears acceptable: symptomatic ICH rates of 4% with aspirin vs 17% without in one series 2

Timing of Antiplatelet Therapy

• The 24-hour window is critical: antiplatelet agents are contraindicated within 24 hours of thrombolysis administration 2
• After this window and hemorrhage exclusion, aspirin should be initiated promptly for secondary stroke prevention 1

Common Pitfalls to Avoid

• Do not reflexively give aspirin loading based on cardiac ACS protocols—stroke thrombectomy has different bleeding risk profiles 1
• Do not withhold aspirin indefinitely after the 24-hour post-thrombolysis scan if hemorrhage is excluded—delayed initiation increases recurrent stroke risk 1
• Do not avoid emergent stenting due to concerns about aspirin administration—when stenting is required, intraprocedural aspirin appears safe and may improve outcomes 2, 3

Special Circumstance: Emergent Stenting Required

If acute carotid or intracranial stenting is necessary during thrombectomy:

• Administer IV aspirin 250-500 mg intraoperatively at the time of stent placement 2, 3
• This can be done even in patients who received thrombolysis, as registry data shows acceptable safety profiles 2
• Continue with oral aspirin 75-100 mg daily plus a P2Y12 inhibitor (clopidogrel 75 mg) after the procedure once hemorrhage is excluded 1