Principal Developer: R. Cote
Secondary Developers: G. Deveber, A. Roussin

Background

Stroke constitutes a major medical problem representing one of the most common causes of mortality and disability. Although strokes can be of an hemorrhagic nature, ischemic strokes are by far the most common ones accounting for approximately 85% of all strokes.

Epidemiology

Annually, almost 50,000 new cases of stroke occur in Canada and the associated short term mortality is about 20 – 25%. Of the 200,000 stroke survivors in Canada approximately 40-50% are left with varying degrees of disability affecting activities of daily living. The prevalence of stroke increases with age and other risk factors such as hypertension, smoking, and associated cardiac conditions such as atrial fibrillation. The risk of experiencing an ischemic stroke after an initial stroke or after a transient ischemic attack (TIA) is approximately 10-12% in the first year.

* If symptomatic carotid stenosis (=70%) endarterectomy indicated. Endarterectomy can also be considered in some patient with =50% symptomatic carotid stenosis.

• Acetylsalicylic Acid (ASA): Drug most commonly used for stroke prevention, recommended dosage is between 50-325 mg/day.. Side effects are mostly GI related including peptic ulcer disease.

• Clopidogrel: Analog of ticlopidine but with better safety profile. Comparable antiplatelet effect showing a modest advantage over ASA for prevention of ischemic events and no increased incidence of neutropenia compared to ASA. The dosage is 75 mg once a day. Clopidogrel should be used in cases where ASA has failed, is not tolerated or an allergy to ASA exists.

• Dipyridamole: Dipyridamole in combination with low dose ASA has been shown to be effective for stroke prevention. The combination of ASA 50mg/day and dipyridamole slow release 400mg/day has been shown to reduce the risk of stroke by approximately 23% compared to ASA. Common side effects of dipyridamole include headache and increased frequency of angina.

• Ticlopidine: Slightly superior to ASA for preventing stroke but less well tolerated. Dosage of ticlopidine,is 250 mg b.i.d. Common side effects include diarrhea and rash. Hematological complications include severe neutropenia in 0.8% of cases. Close monitoring of neutrophil count is suggested every 2 weeks for first 3 months. Increased incidence of thrombotic thrombocytopenic purpura has also been reported.

The following is a semi-quantitative evaluation of antiplatelets for the prevention of stroke and other vascular events based on selected criteria and available evidence.

Because of its efficacy, safety and cost, ASA should remain an antiplatelet of first choice for ischemic stroke prevention. The combination ASA/DipyridamoleSR can also be considered for initial therapy. Alternatives to ASA for second choice would include clopidogrel or the combination of ASA /DipyridamoleSR.

• Warfarine: Oral anticoagulants have been shown to provide more benefit in certain conditions where the mechanism of ischemic stroke is presumed to be cardioembolic (atrial fibrillation, post MI) [See guidelines for these specific conditions] or in the case of cerebral sinovenous thrombosis.Recent evidence does not support it’s use over ASA for the prevention of recurrent stroke after a first noncardioemblic ischemic stroke.

Childhood stroke