The Guidelines on Stenting vs Endarterectomy
A Review and Perspective
Henry R. Black, MD; Jonathan L. Halperin, MD
Henry R. Black, MD: Hi. I'm Dr. Henry Black, Clinical Professor of Internal Medicine at New York University School of Medicine, a member of the Center for the Prevention of Cardiovascular Disease, and immediate past president of the American Society of Hypertension. I am here with my colleague, Dr. Jonathan Halperin. Jon?
Jonathan L. Halperin, MD: I'm Jon Halperin, a cardiologist and Professor of Medicine at Mount Sinai School of Medicine in New York City.
Dr. Black: You have participated in writing some guidelines, especially about what to do with carotid stenting vs surgery. How do you work that out, and what were the findings of the trials that we had until now?
Dr. Halperin: The management of patients with carotid artery disease has been a controversy going back a number of decades. We learned more than 20 years ago that carotid endarterectomy can be a highly effective treatment that prevents stroke in properly selected patients.
Dr. Black: It was only in properly selected patients. Who were they?
Dr. Halperin: For the most part, the best evidence is for symptomatic patients, patients who had experienced a transient ischemic attack or a nondisabling stroke related to severe stenosis of the carotid artery that supplies the affected side of the brain. What we should do for patients with asymptomatic carotid stenosis is a bit more controversial, in part because medical therapy has improved substantially over the decades. The trials that demonstrated the superiority of carotid endarterectomy over medical therapy were conducted in an era when medical therapy was less effective and less robust than it is today.
A more recent treatment is carotid artery stenting, which is popular because of the appeal to a patient who doesn't require an incision in the neck, but of course patients are also potentially prone to complications related to the associated vascular disease and the need to navigate what is often a very diseased circulation.
Dr. Black: Aren't you concerned about embolization from the stenting?
Dr. Halperin: We are. As a result, there has been the development of embolism protection devices -- little baskets that trap some of the debris. Embolism is a concern with any cardiovascular manipulation, and it certainly plays importantly into the decision-making when choosing a treatment].
A number of attempts were made to compare these 2 technologies. Of course, whenever you try to compare interventional procedures, lots of things come to bear. For example, how experienced were the operators who performed the treatments? How well-balanced were the treatment groups with respect to randomization? Were there biases that kept the typical patient out of the trial when someone thought they knew what was best?
Dr. Black: How do you do a randomized trial in which surgery is one of the arms?
Dr. Halperin: First, you have to identify a patient who is a potential candidate for either technique. Then, you have to inform the patient that neither of these 2 treatments has been shown to be superior to one another, but perhaps they have only been shown to be superior to medical therapy without intervention. You have to very carefully lay out for the patient the pros and cons of what we know about each of these technologies, and then ultimately trust in the patient's confidence in the physicians who tell them that the best thing to do is to be randomized, because when we don't know what to do, outcomes are best for people who participate in well-designed, properly conducted trials.
Dr. Black: I'm sure you recall the Vineberg operation, where people just had their chest opened and closed. It turned out not to help coronary disease, as was anticipated, but you still had to do that so that the patients would wake up not knowing what happened to them.
Dr. Halperin: Right. There was the famous Glover procedure, in which patients actually had sham operations -- something that no one would consider ethical today -- with doctors making an incision and doing nothing. The people who were in the so-called placebo or control group felt terrific oftentimes the day before they died. It is a real concern, and I think the ethics of these trials has to be handled very carefully. That has been done very nicely in the more common trials.
Dr. Black: When we do guidelines, how do you make them? What do you decide is going to be a recommendation, and who participates in those committees?
Dr. Halperin: We are very careful to select the writing committee members with a good deal of balance. We try to bring people who represent expertise in all of the various options, including not only the surgeons and stenters but also neurologists, neurosurgeons, nurses, and others who are experts in the overall management of patients with carotid disease.
We have done this with a very nice multisociety guideline that was handled under the aegis of the American College of Cardiology and the American Heart Association Task Force on Practice Guidelines, and it was published in early 2011.[1] I think it represents one of the most impressive consensus-based statements yet developed. We have recommendations that refer to one of these technologies as a reasonable alternative to the other, but of course, that requires a good deal of clinical judgment. The writing committees struggle with these issues in trying to voice recommendations that cover this problem.
Dr. Black: When people line up levels of evidence and how important each one is, one thing that is always at the bottom is clinical judgment. The trials are a problem. If you enroll people in a trial, but the patient you are dealing with wouldn't have been in that trial, can you use that evidence? I don't think so.
Dr. Halperin: That's right, and we should also remember that guidelines are about diseases, but we take care of patients
Dr. Black: Yes, guidelines are guidance; they are not laws. Do you think they should they be used for payment decisions?
Dr. Halperin: I think they represent our assessment of the best available evidence. As a result, payment decisions could logically draw their conclusions from the summary of information that appears in the guidelines. But guidelines are not written with the idea of reimbursement. They are trying to guide caregivers in how to weigh the evidence and make what they think might be the best decision.
Dr. Black: If I were dealing with a patient who had a problem that I didn't know much about, that is the first place I would turn. If it is something that I do know about, I know that I can do better than a guideline, because I have the expertise and the judgment that does not count necessarily as evidence in order to decide what to do. That makes us more and more specialized.
One of the things that has always occurred to me is that legal evidence, which is always challenged in court, has to be relevant. That is a reason to allow something to be discussed.
How relevant is a trial done in the United States to a patient in Norway, and how relevant is a trial done in Norway to a patient in the Philippines? I don't necessarily think that it's very relevant, so medical evidence and legal evidence are not the same.
Dr. Halperin: You are absolutely right. As physicians, I think we need to look at a guideline recommendation, look at the evidence from which it was derived, and ask, "How well does my patient fit that description? Can I actually apply that piece of information, or are there special case-based considerations?" They might be related to nationality, healthcare systems, or patient individuality even at the genetic level, where we have to decide that we cannot apply that. There may be a modifying factor, a difference in risk, a difference in patient preferences, all of which have to play into our clinical decisions.
Dr. Black: In CREST,[2] how did that turn out? What did the investigators find?
Dr. Halperin: The overall finding in the trial was for patients with either symptomatic or asymptomatic carotid stenosis. Outcomes in terms of stroke and overall mortality were very comparable between patients who were randomly assigned to carotid endarterectomy and patients who were randomly assigned to catheter-based carotid intervention with stenting. However, if you look closely at the data, you'll see that older patients seemed to do better with the surgical approach. Younger patients seemed to do better with the catheter-based approach.
These secondary analyses are exploratory and hypothesis-generating. They require additional study to confirm what appears to be a potentially valid observation, but we have to always be cautious when we look beyond the primary outcome into the subsidiary analysis before we draw conclusions.
Dr. Black: When I was doing animal research, which was a long time ago, I used to read the methods first. That is how I was trained. I thought that if the methods were inadequate, I didn't need to read past that, because I couldn't use the answer.
The same thing should happen when we are dealing with a patient. If you look at a trial with a condition that your patient has, you ought to see what the methods were. If your patient does not fit into the methods, either ignore it or be sure to explain to the patient that even though the study said it didn't matter, your group was not studied and, in my opinion, this is what you should do.
Dr. Halperin: I think that applies here as well. We have to be very careful. First of all, is the patient symptomatic or not? Second, what is the severity of the carotid stenosis? This requires study, generally by carotid ultrasound and sometimes by additional forms of imaging.
Third, how does it apply to the community in which I practice? How well-trained were the surgeons, and how well-trained were the catheter-based interventionists? If they were adequately trained, as I think they were in such trials as CREST, then we can begin to draw valid conclusions. However, if you are in a community where the operators have much less experience with one technology compared with the other, that should play heavily in choosing the technology with which your patient does best.
Dr. Black: I completely agree. Using trials these days has become a very interesting procedure indeed, as writing guidelines is.
Dr. Halperin: Indeed, it is a challenge, but a very enjoyable one, because we are looking at the best available evidence and trying to develop an appropriate assessment for patients and caregivers of all stripes that we can apply as broadly as we can across the field.
Dr. Black: One thing that occurs to me is that if you are on one of these committees, you need to sign the final document, or you should get yourself out of that committee from the beginning.
Dr. Halperin: That's right. I think it's very important to try to avoid the biases that so often enter into these types of interactions, and we have been very careful about that in the guidelines.
Dr. Black: Thank you very much, Dr. Halperin.
Dr. Halperin: Thank you.
References
1.Writing Committee Members, Brott TG, Halperin JL, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American Stroke Association, American Association of Neuroscience Nurses, American Association of Neurological Surgeons, American College of Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, Society of Atherosclerosis Imaging and Prevention, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, Society for Vascular Medicine, and Society for Vascular Surgery. Stroke. 2011;42:e464-e540. Abstract
2.Brott TG, Hobson RW 2nd, Howard G, et al; CREST Investigators. Stenting versus endarterectomy for treatment of carotid-artery stenosis. N Engl J Med. 2010;363:11-23. Abstract
鏈接：The Guidelines on Stenting vs Endarterectomy
A Review and Perspective
