Stroke of genius � if it doesn't kill you

Carotid endarterectomy reduces stroke risk
by 50% but surviving the op is the tricky part

By William D Donaldson

The simplest ideas are usually the best, and sometimes the answers to the most difficult questions have been staring us in the face the whole time. Cleaning out fatty deposits from the carotid arteries before any adverse events occur looks to be one such idea. But would this theory hold up in practice? A new report says 'yes' ... well, for the most part.

The May 8 issue of The Lancet carries a report by Dr Alison Halliday of St George's Hospital Medical School in London on one of the most successful stroke prevention interventions in the history of medicine. It confirmed the findings of previous research, which found that carotid endarterectomy could cut stroke risk by half. Endarterectomy is the removal of fatty deposits in the carotid arteries of asymptomatic atherosclerosis patients.

The British study involved 3,120 asymptomatic patients with substantial carotid narrowing, who were randomized into a carotid endarterectomy group and an observation-only group. The researchers then keep track of who got hit by a stroke in the next five years.

Overall, 6.4% of the patients who underwent carotid endarterectomy suffered a stroke in the following five years, compared to 11.8% of the patients in the observation group. If only fatal strokes were considered, 2.1% of the carotid endarterectomy patients underwent such an event in the five-year period, compared to 4.2% of the untreated patients. In other words, the procedure brought a 50% risk reduction in patients with significantly narrowed carotid arteries.

Neurologist Dr James Toole of Wake Forest University Baptist Medical Center in North Carolina was one of the first to study carotid endarterectomy. He believed that people with diabetes, hypertension or a family history of stroke should be screened in their 40s. The screening can be simply and safely performed with ultrasound.

"We now know definitively that we can reduce stroke risk by half with surgery to clean out narrowed arteries leading to the brain � even in patients who have no symptoms. We should offer this option to more patients, as well as begin screening seemingly healthy individuals for stroke risk," claimed Dr Toole.

Nonetheless, among patients in the carotid endarterectomy group who did suffer strokes, nearly half were apparently triggered by the operation itself. So among treated patients who were stroke-free one month after surgery, stroke risk over the next five years was actually closer to a quarter rather than half the control group's risk.

For carotid endarterectomy to become a widespread procedure, physicians would have to be willing to recommend asymptomatic patients for surgery that will kill or disable about 1.6% of them � and some of these patients are as young as 40. Yet the benefit would be a dramatic reduction in strokes caused by carotid stenosis, which currently accounts for nearly a third of all ischemic strokes. The potential for a medico-legal-ethical nightmare is clear.