Frank J. Veith, MD


July 25, 2011

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CAS and the AHA Guidelines: Not so Fast

I'm Frank Veith. I'm Professor of Surgery at New York University Medical Center and the Cleveland Clinic. And today, we're going to talk about the treatment of carotid disease: the old and the new, the old being carotid endarterectomy and the new being carotid stenting. We're going to talk about the Carotid Revascularization Endarterectomy vs Stenting Trial(CREST),[1] the American trial, and the International Carotid Stenting Study (ICSS),[2] the European trial. And we're going to talk a little bit about the American Heart Association (AHA) guidelines, which have been approved by many societies in the United States.

To start with, symptomatic carotid disease and asymptomatic carotid disease, although they're both related to arteriosclerosis, are really quite different disease processes. Symptomatic disease is a harbinger of stroke or further strokes and it justifies invasive treatment. Asymptomatic carotid stenosis is a more benign condition. It has less potential for causing a stroke. It causes fewer strokes now than it did in the past. And it's really a disease with a different pathology, different plaque characteristics, and so forth.

I'd like to confine my remarks this morning to symptomatic carotid disease. And then perhaps in a subsequent discussion, we can talk a little bit more about asymptomatic carotid stenosis. The CREST, which is an American trial, was designed to evaluate and compare carotid endarterectomy with carotid stenting in patients with symptomatic carotid stenosis. And because they had trouble recruiting enough such patients or adequate numbers of such patients, they added patients with asymptomatic carotid stenosis to the study and had about an equal number of the 2 varieties.

CREST also had a rather peculiar endpoint, which included stroke, death, and myocardial infarction. And when that adverse event endpoint was compared, carotid endarterectomy and carotid stenting were about equal up to 4 years. And the interpretation of that trial, or misinterpretation and we'll talk a little bit more about that, was that carotid stenting was the equivalent of carotid endarterectomy.

However, that conclusion, which was published in The New England Journal of Medicine last June, is perhaps incorrect or a misinterpretation, because if one looks at the actual numbers of strokes and deaths in the carotid stenting arm of the study, there are about twice as many as there are in the carotid endarterectomy arm. And only when myocardial infarctions, many -- or all -- of which were quite minor, were added as an adverse event did the composite endpoint show equivalence.

So one could interpret CREST results as carotid artery stenting causing more strokes and deaths and, therefore it is not yet the equivalent of carotid endarterectomy. In addition, CREST had the flaw of mixing symptomatic and asymptomatic patients. Then they had this flawed, or possibly flawed, endpoint, although this still remains controversial.

The AHA guidelines, which were based largely on CREST, had as one of their major conclusions that carotid stenting is an alternative to carotid endarterectomy. And in view of the higher stroke rate with carotid stenting, that interpretation of the AHA guidelines conclusion is open to some question.

In addition, there are many other trials, some of them recent and notably the ICSS European trial,[3] which clearly show that carotid endarterectomy has a lower stroke rate, lower death rate, and lower complication rate than carotid stenting. Some of the individuals who perhaps are a little biased toward carotid stenting will say that the carotid stenters in the ICSS trial weren't necessarily up to speed with their technical performance and experience and so forth. And, therefore, the ICSS trial is perhaps imperfect.

Two other things I neglected to mention. The ICSS trial, the European trial, was done entirely on symptomatic patients. And the other point I'd like to mention is that at our New York symposium this November on vascular diseases in general, we're going to highlight some of the controversies, many of them related to carotid artery disease. And many of these points will be discussed in greater detail.

And finally, even though the trials and the data to date seem to suggest, at least to my bias, that carotid endarterectomy is still superior to carotid stenting for the treatment of symptomatic carotid artery disease, I still remain a carotid stenting enthusiast. There have been many improvements in the technique of performing carotid stenting, better stents, better embolic protection devices, better patient selection. And it's my belief that with these improvements, the results of carotid stenting will be sufficiently better than they were in both CREST and ICSS and that carotid stenting will play a major role in the treatment of many patients with symptomatic carotid stenosis. The bottom line at present, however, is that we're not there yet.


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