CAE vs. CAS heatedly debated at ISC session

By Larry Haimovitch

Medical Device Daily Contributing Writer

February 14, 2011

LOS ANGELES — The purpose of a clinical trial, particularly a huge, multi-center, prospective and randomized one, is to provide sufficient data to guide physicians to deliver the best care for their patients. The vast majority of trials, whether device or drug-based, generally achieve this goal.

However, based on the heated debate about how to treat carotid artery stenosis that occurred at this year's International Stroke Conference, which is sponsored by the American Heart Association (AHA; Dallas), that clearly does not appear to be the case.

Recall that the 2010 conference featured the release of data from the landmark and keenly anticipated Carotid Revascularization Endarterectomy versus Stenting Trial (CREST). Sponsored by the National Institutes of Health (Bethesda, Maryland), CREST enrolled more than 2,500 patients at 117 centers in the U.S. and Canada and took a remarkable nine years to complete.

Patients were randomized 1:1 to either carotid stenting (CAS) or carotid endarterectomy (CEA), with just over half the patients with symptomatic disease. The primary endpoint was a composite of any stroke, myocardial infarction (MI) or death within 30 days. The secondary endpoints contrast CEA and CAS by symptomatic events, sex, restenosis and health-related quality of life (QOL) and cost.

The conclusion from last year's conference was essentially that either procedure is a good way to treat carotid artery occlusions and thus to limit the risks of having a stroke. The choice between the two procedures could be more a matter of patient preference than scientific certainty.

Stated differently, Wayne Clark, MD, a vascular neurologist from Oregon Health Sciences University Medical Group (Portland) said, "I am excited to say that we now have two very good options to prevent stroke."

Further, the lead CREST investigator Thomas Brott, MD of the Mayo Clinic (Jacksonville, Florida) indicated last year that while the stroke and heart attack rates were different "unfortunately, there is not a lot of scientifically valid information that tells us which is more important to the patient."

A recent guideline document, titled "Guideline on the Management of Patients With Extracranial Carotid and Vertebral Artery Disease" was published in the January 2011 issue of Circulation. Developed with experts from the AHA and the American College of Cardiology (Washington) and several other medical societies, it essentially echoes these viewpoints.

The October 2010 issue of Endovascular Today was heavily devoted to this topic, with an editorial from the chief medical editor's page titled "The CAS Data Puzzle." The issue contained numerous articles on the topic from some of the world's most renown experts from vascular and cardiovascular surgery to interventional neurologists, cardiologists and neuroradiologists.

Clearly, CREST is a highly important study and the massive interest in this subject was exemplified here at a session on Thursday morning, with a standing room only crowd to attend talks on "Carotid Angioplasty and Stenting versus Endarterectomy." From the size of the audience to the passionate views from speakers and the audience in a lively Q&A, it was clear that the controversy is still very much alive and indeed, far from being resolved.

The session's moderator Seemani Chaturvedi, MD, professor of neurology at the Wayne State School of Medicine (Detroit), kicked off the proceedings, saying that it is especially timely, a year after CREST was unveiled, to re-visit the data and update the medical community. He further noted that recent regulatory developments made it even more important to review treatment options.

Chaturvedi's reference to new regulatory events concerned an FDA Circulatory Systems Devices Panel advisory committee meeting that took place on January 26. The committee considered the application from Abbott Vascular (Abbott Park, Illinois) to broaden the indication for its RX Acculink carotid artery stent and companion embolic protection device, the RX Accunet, from patients who are at high risk for a carotid artery endarterectomy procedure to those who are at standard risk (Medical Device Daily, Jan. 28, 2011).

With a 7-3 affirmative, the panel basically supported the CREST data and voted to expand the label for this patient population. Final FDA approval is presumably going to follow in the next few months, although the FDA is certainly not obligated to follow the committee's recommendations.

The session here began with Jorg, Ederle, MD, from the Stroke Research Group, Institute of Neurology (London), who provided a detailed review of the various trials that have been conducted around the world in the past several years. His two main conclusions were that CAS is riskier than CEA (due to a higher stroke rate) especially in asymptomatic patients and that the efficacy of the two approaches is quite similar, particularly a few years after the procedure has been performed.

Robert Harbaugh, MD, chairman of the department of neurology at Penn State Hershey Medical Center (Hershey, Pennsylvania), provided an extensive analysis of the CREST data, noting that the results were quite similar. He was adamant in his opinion that "symptomatic patients are the most important to treat" and later in his remarks, slammed CAS, saying "it is criminal to treat these asymptomatic patients with stenting and angioplasty."

Adnan Siddiqui, MD, assistant professor of neurosurgery and radiology at State University of New York (Buffalo, New York), was the final speaker of the session. He took a more balanced approach in his prepared remarks, commenting that "equipoise has been reached" and that "both approaches are very complementary." He noted that the rate of adverse events in carotid stenting has significantly declined with the addition of distal protection devices. This benefit was first demonstrated in the SAPPHIRE trial in 2005 and has continued to be a boon to CAS procedures, according to Siddiqui.

A lively question and answer period brought emotions to a head with Harbaugh and Siddiqui strongly disagreeing on the role of CAS vs. CEA. Harbaugh again reiterated the "criminal" word in regard to Medicare patients being "over-stented," adding that "if we perform stenting procedures on asymptomatic patients, we will cause more strokes than we will prevent."

All physicians in the session agreed that another study, measuring CEA and CAS against medical management was sorely needed. Chaturvedi noted that medical management has improved significantly in recent years and that many neurologists contend that most patients can be successfully managed medically.

"We desperately need the stroke neurologists to help us decide which therapy is best for each patient," he said.

A final indication of the smoldering nature of this disease, which accounts for an estimated 125,000 to 150,000 procedures per year in the U.S. is that a few days before this meeting, the cerebrovascular section of the American Association of Neurological Surgeons (AANS; Rolling Meadows, Illinois) met in Los Angeles. According to a research report written by analyst Josh Jennings of the investment banking firm Jefferies & Co. (New York) a lively CREST debate at AANS occurred because "neurosurgeons are at risk of losing carotid endarterectomy procedure volumes."

Jennings went on to opine that "we now believe that carotid artery stenting procedures can increase five-fold on the heels of a positive panel (meeting) for Abbott's Acculink and pending a positive reimbursement decision by CMS and commercial payers over the next four to five years . . ."

2011 International Stroke Conference

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