Atherothrombosis and the role of antiplatelet therapy.

Atherothrombosis remains a major global public health problem. Chronic atherosclerotic disease is often clinically silent and coexists across vascular beds, but when complicated by thrombosis can result in acute coronary syndrome, stroke, transient ischaemic attack and critical limb ischaemia. Platelets play a role in the development of chronic atherosclerotic disease and are a key mediator of clinical events in atherothrombosis. Numerous trials have examined the role of antiplatelet agents in primary and secondary prevention and several new antiplatelet drugs are under development. In secondary prevention, there is evidence of clear benefit of single and in some cases dual antiplatelet therapy in the prevention of recurrent cerebro-vascular complications. Dual antiplatelet therapy has emerged as the standard of care in acute coronary syndromes, with aspirin typically being used in combination with clopidogrel or one of the newer more potent antiplatelet agents. Conversely, in chronic stable coronary disease, no benefit has yet been convincingly demonstrated from dual antiplatelet therapy. In cerebro-vascular disease, aspirin monotherapy remains the cornerstone of prevention of recurrent events, with clopidogrel or the combination of aspirin and dipyridamole being only modestly more efficacious. In primary prevention, the evidence for the routine use of aspirin or any other antiplatelet agent is mixed and suggests this should only be considered on an individual basis in high-risk groups where the thrombotic risk outweighs the risk of major bleeding complications.