Especially after a TIA or mildly disabling stroke, a large gain can be achieved by preventing subsequent (disabling) strokes or myocardial infarcts. Besides the individual benefit for patients and their families in terms of reducing the risk of subsequent vascular events, there will be a reduction of demands on health and social care, which will lead to practical and economic benefits. Because of the high incidence of this health problem, any improvement would benefit a large proportion of the population.

One of the means of secondary preventive treatment is antithrombotic drugs. This article provides a review of antithrombotic therapy in patients with a presumed arterial—i.e. non-cardioembolic—source of stroke to advise physicians on which antithrombotic they should prescribe to patients after ischemic stroke to prevent subsequent vascular events.

Aspirin
In the secondary prevention of important vascular complications after ischemic stroke, the use of the antiplatelet drug acetylsalicylic acid (aspirin) in doses between 30 and 325mg per day is generally accepted.^5,6 Based on data from the AntiThrombotic Trialists’ Collaboration Group⁷ and the Dutch TIA Trial, which compared the efficacy of 30 versus 283mg aspirin daily in patients after cerebral ischemia,⁶ it is estimated that 30–300mg aspirin daily prevents only 13% of vascular complications in patients who had an episode of cerebral ischemia (95% confidence interval (CI) 6–19).^8,9 This risk reduction is far from ideal as 87% of major arterial complications are not avoided.

Clopidogrel
Other antiplatelet drugs are clopidogrel and ticlopidine, which are thienopyridine derivates. In all patients with vascular disease included in the CAPRIE study—which included patients with cerebral ischemia, myocardial infarction, or peripheral arterial disease—there was a modest reduction with clopidogrel 75mg daily compared with aspirin 325mg daily in the secondary prevention of major vascular events. The relative risk reduction was 8.7% (95% CI 0.3–16.5). The relative risk reduction among those patients who presented with ischemic stroke was 7.3% (95% CI -5.7–18.7) in favor of clopidogrel, but this was not statistically significantly better than aspirin.¹⁰ To prevent one vascular complication, about 200 patients would need to be treated with clopidogrel instead of aspirin for one year. In addition, clopidogrel is more expensive than aspirin. Since clopidogrel has a different adverse effect profile, it can be used in patients who cannot tolerate aspirin. In a systematic review, the thienopyridines appeared to be modestly more effective than aspirin in preventing serious vascular events in high-risk patients.¹¹ Clopidogrel appeared to be safer than ticlopidine and as safe as aspirin.