Meta-analyses: Aggrenox® is the preferred antiplatelet regimen to reduce the risk of recurrent vascular events

June 2007

One strategy of reducing the burden of stroke is the prevention of recurrent stroke, following an initial ischaemic stroke or transient ischaemic attack (TIA) of arterial origin, by means of antiplatelet therapy.

Graeme J. Hankey, MD, from the Stroke Unit of the Department of Neurology, Royal Perth Hospital, Perth, Australia, reviewed and discussed the current clinical trial data and guidelines for the use of antiplatelet therapy in the prevention of recurrent stroke/TIA of arterial origin (not stroke due to atrial fibrillation) based on a huge literature survey. He proposed, based on the latest available evidence, a new antiplatelet treatment algorithm for the long-term treatment of patients following a atherothromboembolic ischaemic stroke or TIA.

His meta-analyses of randomised clinical trials in patients with TIA and ischaemic stroke of arterial origin indicated that, compared with control, the relative risk reduction (RRR) for recurrent stroke and other serious vascular events is 13% (95% confidence interval [CI] 6% to 19%) with aspirin, 13% (4% to 21%; p = 0.046) with dipyridamole and 34% (24% to 43%) with the combination of aspirin and dipyridamole.

A major result of his meta-analyses was that, compared with aspirin, the relative risk of recurrent stroke and other serious vascular events is reduced by 7.3% (95% CI 5.7% to 18.7%) with clopidogrel and 18% (9% to 26%; p = 0.0003) with the combination of aspirin and dipyridamole. Although the RRR for recurrent stroke greater for those who were treated with a combination of aspirin and dipyridamole than for those who were only given clopidogrel, it should be noted that the combination therapy is not significantly more effective in preventing serious vascular events than the treatment with clopidogrel alone (RRR 6.4%; 4.6% to 16.3%) in the long-term treatment of patients with previous ischaemic stroke and TIA.

Dr. Hankey restated the relative risks and benefits of long-term treatment with clopidogrel and the combination of aspirin and dipyridamole are being compared in an ongoing large clinical trial (PRoFESS). Current Australian therapeutic guidelines for antiplatelet therapy among patients with TIA and ischaemic stroke of arterial origin have incorporated important new findings from recently published clinical trials and recommend aspirin or the combination of dipyridamole plus aspirin as the preferred long-term antiplatelet therapy.

Graeme J. Hankey concluded that whilst awaiting the results of the PRoFESS trial, the combination of dipyridamole plus aspirin is the preferred antiplatelet regimen to reduce the risk of recurrent vascular events among patients with TIA and ischaemic stroke of arterial origin.