Treating Asymptomatic Carotid Stenosis Invasively? Not Yet

Medscape Published: August 4, 2011

My opinions against invasive procedures for asymptomatic carotid stenosis until good trials can determine the best candidates. View video here. You
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I'm Frank Veith. I'm Professor of Surgery at New York University Medical Center and the Cleveland Clinic. The last time I spoke, we discussed symptomatic carotid disease and its treatment and some of the controversies surrounding the recent CREST[1] and ICSS[2] trial and the American Heart Association (AHA) guidelines.[3]

In this particular discussion, I would like to devote some attention to the treatment of asymptomatic carotid disease. I stressed in the past that asymptomatic and symptomatic carotid diseases are quite different disease processes with different prognoses, different pathologies, different natural histories, and that the two, even though they're related, shouldn't necessarily be considered together.

Asymptomatic carotid disease or carotid stenosis is really a very benign condition. First of all, there are many, many more patients who have asymptomatic carotid stenosis than those that have symptomatic disease. In addition, with advances in medical treatment over the last 15 years comprised of statins, better blood pressure control, better smoking control, better diabetes control, beta-blockers, antiplatelet agents, etc, the natural history of asymptomatic carotid stenosis has become even more benign than it was in the past.

Fifteen years ago, a patient with an asymptomatic carotid stenosis had a 3%- 6% chance per year of having a stroke. Now presumably because of best and improving medical treatment, but perhaps for other reasons, a patient with asymptomatic carotid stenosis has less than a 1% chance per year of having a stroke.

Because of this benign condition, the idea of operating, of doing a carotid endarterectomy (CEA) or a carotid arterial stenting (CAS) on a patient with asymptomatic disease, becomes less supportable. One would have to do many unnecessary procedures -- probably in the range of at least 20 -- to prevent 1 stroke. Most of the studies showing that endarterectomy is better than best medical treatment were done with obsolete medical treatment, no statins, and none of the other modalities or drugs that I mentioned.

The idea of operating on every asymptomatic carotid stenosis of a high degree is really in my opinion, again my bias, indefensible. What we need in order to find patients with asymptomatic carotid stenosis who should be treated invasively are better ways of selecting out the patients within this large group -- a small group of patients who really are at high risk of having a stroke.

There are glimmers of hope that such methods will become feasible in the next several years. We don't need to go into the details, but with better imaging, better transcranial Doppler imaging looking for evidence of embolization, and better evaluations of patients' risk stratification, we will be able to pick out a high-risk group of asymptomatic patients who justifiably can be treated either with CEA, or CAS.

At the present time, we don't think that's possible. The conclusion is that we need to treat, or we should be treating, most asymptomatic carotid stenosis patients with best medical management and not intervening on most of them.

Obviously, there's probably a select group within the asymptomatic carotid stenosis population that should have interventional therapy. How to identify that group is one of the challenges for the future.

In addition, we need good randomized trials that compare best medical therapy with both CEA and CAS. Some of those trials are being proposed or are in the works, but we won't have answers for at least 5 years.

In the meantime, just let me add that many of the controversial aspects of what I've mentioned this morning reflecting biases that are more conservative even than mine and those that are interventionally directed, many of these will be discussed at our upcoming November vascular symposium here in New York City.