ASA/AHA

ASA/AHA = American Stroke Association/American Heart Association

The American Heart Association (AHA) published their new “Guidelines for Prevention of Stroke in Patients With Ischaemic Stroke or Transient Ischaemic Attack” in Stroke 2006 (Sacco et al. Stroke 2006; 37 (2): 577-617). The aim of the AHA's new statement is “to provide comprehensive and timely evidence-based recommendations on the prevention of ischaemic stroke among survivors of ischaemic stroke or transient ischaemic attack.”

Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for non-cardioembolic stroke.

Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinaemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral haemorrhage; and special approaches for the implementation of guidelines and their use in high-risk populations.

The fourth item deals with “Antithrombotic Therapy for non-cardioembolic Stroke or TIA (especially Atherosclerosis, Lacunar or Cryptogenic Infarcts).”As the guidelines stress, four antiplatelet agents have been shown to reduce the risk of ischaemic stroke after a stroke or TIA and are currently approved by the FDA for this indication (ASA; Ticlopidine; Clopidogrel; and Dipyridamole plus ASA). For reduction in risk of recurrent stroke, antiplatelet therapy with ASA alone, extended-release dipyridamole plus ASA, or clopidogrel are all options, while oral anticoagulation is not recommended for this indication. However, for patients with paroxysmal or persistent atrial fibrillation, oral anticoagulation with warfarin with a target INR of 2.5 is recommended.

The authors of the AHA guidelines conducted a meta-analysis of the results of 21 randomised trials comparing antiplatelet therapy with placebo. They found that, “in 18,270 patients with prior stroke or TIA, antiplatelet therapy was associated with a 28% relative odds reduction in nonfatal strokes and a 16% reduction in fatal strokes.”