A clinical expert consensus document has been issued by the American College of Cardiology Foundation to inform and guide clinical practice regarding the use of carotid stenting.
“This is the first multidisciplinary document of its type on carotid artery stenting,” Dr. Eric R. Bates, chair of the writing committee, said in an interview. Dr. Bates explained that while there is not enough rigorous evidence available to allow the formulation of evidence-based guidelines, the suggestions made in the consensus document represent a state-of-the-art summary derived from the experience of well-credentialed investigators and the results of registries and clinical trials.
The document is cosponsored by the Society for Cardiovascular Angiography and Interventions, the Society for Vascular Medicine and Biology, the Society for Interventional Radiology, and the American Society of Interventional and Therapeutic Neuroradiology (J. Am. Coll. Cardiol. 2007;49:126–70).
Representatives of six professional societies, including cardiologists, interventional radiologists, neurointerventionalists, and a neurologist, composed the 15-member writing committee. One surgeon was included, but the document was not endorsed by a surgical organization.
Of the almost 1 million stroke-related events occurring in the United States each year, about 5%–12% are caused by carotid occlusive disease that is amenable to revascularization. The consensus document endorses current American Heart Association guidelines that recommend carotid endarterectomy (CEA) in symptomatic patients with stenosis 50%–99%, if the risk of perioperative stroke or death is less than 6%. For asymptomatic patients, CEA is recommended for stenosis 60%–99%, if the risk of perioperative stroke or death is less than 3%, although stenosis greater than 80% is the commonly accepted clinical standard. American Academy of Neurology guidelines indicate that patients eligible for carotid artery stenting (CAS) should be 40–75 years old and have a life expectancy of at least 5 years.
“Although CAS is a new treatment and is still undergoing development and testing, right now it is a reasonable alternative to CEA, especially in patients who are at high risk for CEA,” said Dr. Bates, professor of internal medicine and director of cardiac catheterization at the University of Michigan, Ann Arbor.
When stenting the carotid artery, embolic protection devices (EPDs) should be used to reduce the risk of procedure-related stroke, despite the current lack of randomized studies comparing CAS with and without EPDs, the committee recommends. Physicians who perform CAS must also be skilled in placing EPDs.
Current Centers for Medicare and Medicaid Services reimbursement criteria for carotid stenting is limited to individuals at high risk for CEA with symptomatic stenosis greater than 70%, performed by qualified physicians at qualified institutions using Food and Drug Administration-approved stents. Stenting is reimbursed for high-risk patients (symptomatic stenosis greater than 50% or asymptomatic stenosis greater than 80%) in a Category B Investigational Device Exemption trial or postapproval study.
Due to insufficient evidence, CAS is not recommended for high-risk patients with asymptomatic stenosis of less than 80% or in any patient without high-risk features, and the consensus document suggests that further investigation is needed to evaluate the relative merits of CAS compared with optimal medical therapy. “The benefits of revascularization are negated if the risk of revascularization is high, and the fact that CEA is associated with more risk does not mandate that patients undergo CAS.” The role of CAS in low-risk patients also awaits further clarification.
The document also examined the issues of training and credentialing operators who perform CAS. Operators come from various subspecialties—mostly cardiologists, surgeons, and radiologists—with different backgrounds, experience, and expertise. Regardless of specialty, all “operators should previously have achieved a high level of proficiency in catheter-based intervention, complete dedicated training in CAS, and be credentialed at their hospital.” Operators and institutions are required to track and report outcomes to a national database.
“We tried to go for a fair and balanced document that represents all viewpoints,” said Dr. Gary R. Duckwiler, an interventional neuroradiologist at the University of California, Los Angeles, and a member of the writing committee. “There were areas of significant disagreement about the preparatory training and knowledge necessary to perform CAS, and those are identified in the document. For the most part, we all agree that carotid stenting, at least based on the data we have now, can be an excellent procedure in the appropriate patients.”
CAS, although new, 'is a reasonable alternative to CEA, especially in patients who are at high risk for CEA.' DR. BATES