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Poor outcomes hinder high-risk carotid stenting.

HOLLYWOOD, FLA. -- Carotid artery stenting has become a procedure in search of patients.

Several thousand patients have now undergone carotid artery stenting (CAS) in controlled trials or as part of data-collecting registries, and the periprocedural rates of death and stroke have often surpassed the rates in patients who undergo carotid endarterectomy (CEA). As a result, even physicians who were boosters of CAS in the past now concede that the procedure's current role is limited.

When CAS was first tested clinically, "we took on the highest risk patients, but it turns out that the patients who will benefit most from CAS are low-risk patients, younger patients, and the asymptomatic," Dr. William Gray said at the 19th International Symposium on Endovascular Therapy. The newest data also suggest that patients aged 70 years or older face an increased risk, up from the 80-years-of-age threshold that's been used until now.

"Is carotid stenting ready for prime time? Not yet," said Dr. Mark H. Wholey, chairman of the Pittsburgh Vascular Institute. "We made the mistake in trials of thinking that we could stent everyone, but we can't."

"The balance seems to have shifted back to surgery [CEA]," said Dr. Frank J. Criado, chief of vascular surgery at Union Memorial Hospital in Baltimore. "There is a sort of consensus among experts that certain patients are at high risk from CAS." The high-risk category includes patients who are aged 80 or older; have symptoms caused by carotid stenosis such as minor stroke or transient ischemic attacks; have very tight, preocclusive lesions; have heavily calcified, extensive lesions; and have soft, heterogeneous lesions with unstable plaque, as well as patients with an unfavorable anatomy of the aortic arch, common carotid artery, bifurcation, or internal carotid artery.

CAS is facing a double challenge: high rates of bad outcomes, and the lack of Medicare reimbursement for most patients. The most recent results from trials and registries highlight the high 30-day stroke rates and mortality in many patient subgroups. The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) is funded by the National Institutes of Health and should be completed next year. Outcome data were collected during the lead-in phase in 2000 to July 2005 on more than 1,300 patients treated with CAS at 79 sites by physicians who passed demanding criteria to qualify for the trial. In this select group of operators, the overall, 30-day rate of death or stroke was 4.6%, reported Dr. Gray, director of endovascular services at Columbia University in New York.

The outcomes were substantially worse in higher-risk patients. Among the 27% of patients with symptoms, the 30-day death or stroke rate was 6.5%. Diabetes was another marker of increased risk; patients with diabetes had a 30-day, major adverse-event rate of 5.2%, nearly twice the 2.7% rate in patients without diabetes.

Perhaps the most striking finding from the CREST lead-in data is the impact of age on outcomes. Updated data, from 1,479 patients, showed that the 30-day rate of death or stroke in patients aged 80 or older was 11.3%, and in those aged 70-79 the rate was also high, at 5.4%, reported Dr. Gary S. Roubin, chairman of the department of interventional cardiology at Lenox Hill Hospital in New York. The rate in the 70- to 79-year-old group is especially notable because this was the largest age subgroup, with 45% of all patients. In contrast, the rate of bad outcomes was a modest 2.2% in patients aged 60-69, and it fell to 1.5% in patients younger than 60.

In patients aged 70-79, the rate of death or stroke was higher in the asymptomatic patients, 5.6%, than in those with symptoms, who had about a 4.6% rate. The 5.6% rate of bad outcomes in asymptomatic patients in this age group contrasts with the consensus that death and stroke rates in asymptomatic patients undergoing CAS should not exceed 3%.

"I find these results very disquieting," Dr. Roubin said.

The stigma of these statistics is exacerbated by the unwillingness of the Centers for Medicare and Medicaid Services to reimburse the cost of CAS for most patients. CMS currently covers CAS outside of a research setting for about 7% of patients who are diagnosed with high-grade carotid stenosis today in the United States, Dr. Wholey said. These are patients who are at high risk for CEA and who have symptomatic carotid stenosis of 70% or more. Patients at low risk for CEA constitute about 75% of patients with substantial carotid stenosis.

Lack of CMS reimbursement is limiting wider use of CAS, and the CMS will probably continue to restrict reimbursement as long as patients continue to get "suboptimal outcomes," Dr. Roubin said. "Some of the outcomes that we see in the community at large are terrible," he added, caused by poor patient selection and poor technique.

Patients aged 70 and older have a higher rate of contraindicated anatomy for CAS, including problems in their aortic arch, lesion tortuosity, and calcification, Dr. Roubin said. The adverse anatomy that comes with older age poses challenges for patient selection, operator experience, technical skill, and catheter technology. "Carotid stenting will only get CMS approval and wide use when we show in prospective, randomized trials that we know how to select appropriate candidates and optimize our technique to produce credible results."

Refined methods for patient selection for CAS will be a major focus of research and debate in the next few years. Dr. Wholey dismissed the idea of excluding all octogenarian patients from CAS, contending that if this were done routinely the procedure would never be widely accepted.

Instead, he proposed a cautious, multi-step approach. The first stage should focus on evaluating a patient's vascular anatomy with intravascular ultrasound and virtual histology. Patients would then be identified as good candidates for CAS based on a detailed analysis of their anatomic presentation. (See table.)

The intervention itself wouldn't occur until a second procedure a day or two later. And if carotid access can't be achieved within 20 minutes, the operator should just walk away and go with CEA instead, Dr. Wholey said.


Philadelphia Bureau
Should This Octogenarian Get a Carotid Stent?

Stenting should be avoided in patients with a total score of 6 or more.

Clinical Feature Points

Intravascular ultrasound and virtual histology showing plaque is 2
 unstable or thrombotically active
Type III or IV aortic arch lesions 2
Failure to access carotid within 20 minutes 2
Lesion length greater than 2 cm 1
Prior ipsilateral stroke 1
Renal failure or New York Heart Association class III heart 1
Type C carotid stenosis 1

Source: Dr. Wholey
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Title Annotation:Neurology
Author:Zoler, Mitchel L.
Publication:Internal Medicine News
Geographic Code:1USA
Date:Mar 1, 2007
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