BALTIMORE — Gender and timing are two important determinants of success that are usually ignored when surgically treating carotid artery disease. Such omissions result in subjecting patients to the risks of carotid endarterectomy despite their markedly reduced chances of benefiting from the intervention.
Women and those patients treated after several weeks' delay are much less likely to benefit from CEA than are men and those patients treated soon after a symptom (usually a transient ischemic attack), Dr. A. Ross Naylor said at the Vascular Annual Meeting.
The stroke prevention guidelines that have been issued by national health agencies and medical societies use a “one-size-fits-all” approach, said Dr. Naylor, professor of vascular surgery at the University of Leicester (England).
The validity of this approach is undermined by a careful analysis of data that were compiled from three major CEA trials that compared CEA to medical treatment only in a total of more than 6,000 patients. Data from the European Carotid Surgery Trial, the North American Symptomatic Carotid Endarterectomy Trial, and the Veterans Affairs Trial 309 were gathered for analysis by the Carotid Endarterectomy Trialists' Collaboration (Lancet 2003;361:107-16).
Dr. Naylor's analysis of these data showed that among symptomatic patients with 50%–99% carotid stenosis, there was a marked gradation in the rate of ipsilateral strokes prevented during 5 years of follow-up that correlated with the delay between their most recent symptom and surgery (see table).
For example, in patients who underwent CEA within less than 2 weeks of their most recent symptom, the absolute rate of ipsilateral strokes prevented was 18.5%, an “absolutely colossal” rate, he said. In contrast, in patients who had a greater than 12-week delay between their symptomatic episode and surgery the 5-year rate of ipsilateral strokes prevented was 0.8%.
“I can't think of any regulatory agency that would approve a treatment that prevented 8 out of every 1,000 events,” Dr. Naylor said. “If you wait more than 12 weeks, patients face the risk of surgery but get hardly any benefit.”
Many surgeons delay CEA because of the high risk of perioperative death or stroke in patients with symptomatic carotid disease. But even if surgery within 2 weeks caused a perioperative death or stroke rate of 10%, the overall, long-term reduction in strokes in these patients would be grater than if a surgeon were to perform all CEAs after 4 weeks with no perioperative deaths and strokes, Dr. Naylor said.
The danger from delaying surgery is most dramatic in women. In the analysis, women with 70%–99% stenosis had about 40% of their ipsilateral strokes prevented during 5 years of follow-up if their surgery was done within 2 weeks of symptoms. But this benefit fell steeply with any delay in CEA.
If surgery was done 2–4 weeks after symptoms, about 4% of strokes were prevented during 5 years of follow-up. When surgery was delayed beyond 4 weeks, virtually no strokes were prevented during follow-up.
Among women with 50%–69% stenosis, the only subgroup that benefited from CEA comprised those who had surgery less than 2 weeks after symptoms; in this group, CEA prevented about 10% of strokes. Women with 50%–69% stenosis who had CEA done 2 weeks or more after symptoms had an increased number of strokes, compared with untreated women.
In men, delaying surgery was less important, though CEA was still most effective when done less than 2 weeks after symptoms. In men with 70%–99% stenosis, early CEA prevented about 22% of strokes over 5 years, and in men with 50%–69% stenosis CEA within 2 weeks of symptoms prevented about 14% of strokes over 5 years.
By comparison, when surgery was delayed for more than 12 weeks, it prevented about 19% of ipsilateral strokes during 5-year follow-up in men with 70%–99% stenosis, and it prevented about 5% of long-term strokes in men with 50%–69% stenosis, Dr. Naylor said.
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