Surgery to clear blocked arteries that supply blood to the brain is most beneficial in preventing a major stroke if it is performed within two weeks following a minor stroke. If this procedure, called carotid endarterectomy, is performed more than two weeks after a patient has experienced a transient ischaemic attack (TIA) or non-disabling stroke, there may be no benefits at all. Researchers from the Radcliffe Infirmary in Oxford, UK, pooled data from two large trials of carotid endarterectomy, which included nearly 5900 patients recruited after a TIA, non-disabling ischaemic stroke or a blockage of the retina. Subjects were randomly assigned to immediate endarterectomy or medical treatment. For patients with at least 50-percent blockages, time from the last minor stroke symptom to surgery was significantly associated with effectiveness of the procedure. In fact, for patients with 50- to 69-percent blockages, only those treated within two weeks of the onset of symptoms achieved clinical benefits, the authors note. Endarterectomy is often not done until several months after the event - even if the patient seeks medical attention immediately after their warning stroke, according to the researchers. Benefit from surgery is very much reduced at this time, and many patients who would have benefited have their major stroke whilst waiting for surgery.

The Lancet,
March 2004