Antithrombotic Therapy for Cerebrovascular Disorders: Summary and Recommendations
Summary and Recommendations
Transient Ischemic Attacks
1. Definition and occurrence: A TIA is an episode erf neurologic impairment, attributed to focal cerebral ischemia, that resolves completely within 24 h. The annual incidence of first TIAs is about 1 in every 6,000 persons aged 45-54 years and 1 in every 1,000 older persons. TIAs can result from several mechanisms, and the following recommendations apply to TIAs presumed to be due to atherothrombosis.
2. Sisk of thromboembolic events: Patients with TIAs face an annual risk of permanent stroke or death of approximately 10%.
3. Prevention and Therapy:
With aspirin: Nine randomized trials have been published. Fbur level I trials demonstrated statistically significant reductions in the risk of stroke and death from aspirin, and all the other 5 (4 of which had trends favoring aspirin) were level II trials with 95% confidence limits that included aspirin benefits of40-100% in the reduction of stroke and death risk. When the results of all 9 trials are combined, die evidence favoring the efficacy of aspirin is overwhelming.
With anticoagulants: Four level II trials have been published. All were extremely small and generated 95% confidence limits, suggesting that anticoagulant-treated patients could be as much as 100% better off to being 100% worse off than control patients. Both beneficial and harmful trends were observed, and must be interpreted in light of the risks of hemorrhagic side effects. read only
Recommendations: It is strongly recommended that aspirin be administered to patients with TIAs. One study suggests that a lower dose, 900 mg/day, is effective. Whether a higher dose of aspirin is more effective than a lower dose is unproved at present, and therefore it is recommended that patients with TIAs begin aspirin therapy, (1 g/day), unless they are known to have or develop GI intolerance, in which case aspirin (325 mg/d&y) should be given. This grade A recommendation is based on 4 level I studies and an additional 5 level II studies, 4 of which produced trends favoring aspirin.
It is recommended that anticoagulants not be routinely administered to patients with TIAs. This grade B recommendation is based on 4 level II studies that produced trends both favoring and opposing the use of anticoagulants.
Category: Antithrombotic Therapy
Tags: antithrombotic therapy, cardioembolic source, cerebrovascular disorders