Scientists funded by the Medical Research Council (MRC) and The Stroke Association have found that surgery can halve the risk of a stroke for people who have significant narrowing of the main artery carrying blood to the brain. Their findings, published in this week’s The Lancet, are the result of a large-scale international clinical trial.
Strokes happen when the blood supply to the brain is disrupted. Most strokes occur when a blood clot blocks an artery carrying blood to the brain. When the blood supply is disrupted, the brain cells are deprived of oxygen and other nutrients, causing some cells to become damaged and others to die. Some strokes are fatal while others cause permanent or temporary disabilities.
Patients with substantial narrowing of one of the main arteries, the carotid artery, are known to be at increased risk of stroke. But doctors were previously unclear whether a surgical procedure to alleviate the narrowing, known as a carotid endarterectomy, had a clear long-term benefit for such patients, when assessed against the risks of the surgery itself.
The trial compared immediate surgery for patients who had substantial narrowing of their arteries with deferred surgery. Over 3,000 patients in 126 hospitals in 30 countries took part in the study. The trial found that, after five years, people aged 75 and under who had immediate surgery halved their risk of a stroke from 12% to 6%.