• All acute stroke patients not already on an antiplatelet agent and not receiving alteplase therapy should be given at least 160 mg of acetylsalicylic acid (ASA) immediately as a one-time loading dose after brain imaging has excluded intracranial hemorrhage and after dysphagia screening has been performed and passed. [Evidence Level A].
• ASA (81mg daily) should then be continued indefinitely or until an alternative antithrombotic regime is started [Evidence Level A].
• In very high risk TIA patients ( POINT trial criteria of ABCD2 score > 4) or minor stroke of non cardioembolic origin (NIHSS 0-3),
a combination of clopidogrel and ASA should be given for a duration of 21 to 30 days followed by antiplatelet monotherapy (ASA or clopidogrel alone) [Evidence Level A].
• A minimal loading dose of 300 mg Clopidogrel (based on dose in CHANCE) and 160 mg of ASA should be given at the start of treatment [ Level A]
• Dual antiplatelet therapy should be started as soon as possible after brain imaging, within 24 hours of symptom onset, and ideally within 12 hours.
• Dual antiplatelet therapy should be started prior to discharge from the Emergency Department.
• In patients treated with tissue plasminogen activator (alteplase),
initiation of antiplatelet agents should be delayed until after the 24-hour post-thrombolysis scan has excluded intracranial hemorrhage [Evidence Level B].
• In dysphagic patients, ASA (80 mg daily) and clopidogrel (75 mg daily) may be given by enteral tube or ASA by rectal suppository (325 mg daily) [Evidence Level A].
Clinical Considerations:
• Patients with very high risk TIA or minor ischemic stroke caused by high-grade carotid stenosis who are candidates for urgent carotid endarterectomy or carotid stenting, should be reviewed with the interventionalist or surgeon to determine the appropriate timing and selection of antiplatelet agent(s).
• some circumstances it may be appropriate to use aspirin monotherapy rather than dual antiplatelet therapy if carotid endarterectomy is planned urgently, to reduce peri-operative bleeding risk.
• For patients on dual antiplatelet therapy, GI protection may be considered in patients at higher risk of GI bleeding
[ ] Reference
Canadian Stroke Best Practice Recommendations Secondary Prevention of Stroke module sections 6 and 7 for additional information on use of antithrombotic agents beyond the acute period.
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