Asymptomatic Patients With CAS: To Intervene or Not?
Medscape PUBLISHED: September 18, 2013
Should patients with asymptomatic carotid stenting be treated interventionally? You decide but hear my views. View video here. You must be a registered user of Medscape to view the video. Medscape registration is free! Or if you prefer, you can read the article below:
I am Frank Veith, Professor of Surgery at NYU Medical School and the Cleveland Clinic. This morning I am going to provide an update on a very interesting and controversial topic: the treatment of carotid disease in the neck to prevent stroke. I should start out by saying that there are several interesting points about this that will underlie all of my remarks. Number one, this is a very controversial area. Number two, statin drugs and other medical treatments -- but particularly statins -- have made an enormous difference in the underlying disease (arterial sclerosis) and made it less threatening and less dangerous in many ways. The third point is that we are talking about disease in the neck, but the purpose of treatment is not to make the disease in the neck look better but to prevent stroke. Only about 20%-30% of all strokes come from carotid disease in the neck that is amenable to treatment. The fourth point is that there is enormous literature on this, and underlying much of the literature is the bias of the people who are writing the article. Naturally, all of us who do treatments are biased toward our treatments, and that must be kept in mind when reviewing any of the literature.
So, what is new with carotid treatment in the neck? It is important to divide symptomatic carotid disease from asymptomatic carotid disease because the two are quite different in their behavior, natural history, and so forth. When I say "symptomatic carotid disease," I mean really symptomatic carotid disease that produces strokes or amaurosis fugax. It doesn't include patients with headache, dizziness, or other nonspecific symptoms.
Let's first talk about symptomatic carotid disease in the neck. The controversy lies between 2 invasive treatments. One is carotid endarterectomy and the other is carotid artery stenting. Again, there is a lot of controversy, much has been written, and a lot of it is influenced by bias. There are some randomized controlled trials, level 1 evidence. Some of them are good and some of them are not so good, and many of them have flaws. If one looks at these randomized controlled trials, carotid endarterectomy comes out better as a treatment than carotid stenting, in my opinion. Obviously, bias does influence that opinion a little bit, but in all of the studies, the incidence of adverse events, namely stroke, is lower with carotid endarterectomy than with carotid stenting. Even the most recent trial, CREST, has been purported to show equivalence between the 2 therapies but doesn't, in my opinion, because there are more strokes and deaths after carotid stenting than after carotid endarterectomy. The number of myocardial infarctions (MI) that have occurred after carotid endarterectomy is a little higher, and that balances the stroke rate. However, a minor stroke is not equivalent to a minor MI. Minor strokes are much more serious, so I believe that even the CREST trial shows that carotid endarterectomy for symptomatic carotid disease is the superior treatment. However, carotid endarterectomy is fixed. It doesn't improve much. It is an old treatment and it is mature. Carotid stenting is constantly improving; there are better stents, better protection devices, and better techniques. My belief is that in the future, carotid stenting will approach carotid endarterectomy, but the data to date don't show that, and that is important for treating patients today.
What about treatment of asymptomatic carotid disease (carotid stenosis in the neck), which doesn't cause any neurologic symptoms? It is a fairly benign disease, and the controversy is whether one should do carotid endarterectomy to prevent stroke, do carotid stenting to prevent stroke, or use best medical treatment. Best medical treatment includes statins, other drugs such as angiotensin-converting enzyme (ACE) inhibitors, better diet, better hypertension control, and better diabetic control. These comprise best medical treatment, and they have sharply decreased the incidence of stroke in patients with asymptomatic carotid stenosis. About 20 years ago, the stroke rate was 4%-6% per year. Now it is < 1% per year, probably because of all of these medical treatments, most importantly statins. Old trials have demonstrated that strokes are prevented in a small number of patients by intervening with carotid endarterectomy, but since 1990, statins and other treatments have been introduced. The old randomized trials are now obsolete, and many of us believe that most patients with asymptomatic carotid stenosis are best treated medically and not with intervention by carotid endarterectomy or carotid stenting.
When you look at the statistics over the past 5-10 years, most carotid interventions, including endarterectomy and stenting, have been in asymptomatic patients -- up to 90%. In New Jersey in 2009, 96% of all carotid stents were placed for asymptomatic disease. To me that is absurd. That is wrong. Most of those patients would have been much better off being treated medically. That is an opinion. We don't really know. We have the old randomized trials that are obsolete, which many people are still quoting as the reason for intervening on these patients. Then we have the data showing a sharply decreasing stroke rate with good medical therapy, so many of us believe that good medical therapy is best for most patients with asymptomatic carotid stenosis. If one could determine the very few patients with asymptomatic carotid stenosis who are going to have a stroke by using some nice test, then I think those patients should be intervened upon either by endarterectomy or stenting. But so far, we don't have a good way of doing that. There are some experimental methods using transcranial Doppler and other techniques that show promise, but we don't have a universally proven method for picking out the high-stroke-risk patients with asymptomatic carotid stenosis. Therefore, at the present time, I and many of my colleagues will treat most of these patients conservatively with best medical treatment. It seems to be gaining favor, although many still believe that most if not all of these patients should be treated. I think they are affected by bias.
Where is this going to go? Two studies are ongoing, one in Europe (SPACE2) and one in the United States (CREST-2), that are going to compare best medical treatment with carotid endarterectomy and carotid stenting. Probably in 3-5 years, we will have an answer to which patients should be treated by which method. Stay tuned. It is an interesting area and it is highly controversial. I admit to my bias and that most asymptomatic patients are best treated medically -- intensive medical treatment and not by endarterectomy or surgery. As time goes by, we will get more information from these 2 good randomized studies, but this will always be a controversial area because of the bias of the physicians doing the procedures and writing the papers. That is my opinion. I am Frank Veith. Thanks for reading and viewing the video.