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Routine screening for carotid artery stenosis is not recommended for asymptomatic patients with no signs of or risk factors for atherosclerosis -- according to new practice guidelines from the American Stroke Association/American Heart Association, the American College of Cardiology, and several other professional groups.

Duplex ultrasonography might be considered for asymptomatic patients with peripheral arterial disease, coronary artery disease, or an atherosclerotic aortic aneurysm, or for those with at least two risk factors for stroke, the guidelines stated.

"However, it is unclear whether establishing a diagnosis of extracranial and vertebral artery disease would justify actions that affect clinical outcomes" in these patients, according to the guidelines, published simultaneously in the Journal of the American College of Cardiology, Circulation and Stroke, both journals of the AHA, and five other surgical and cardiovascular journals.

The writing committee for the guidelines -- addressing the management of patients with extracranial carotid and vertebral artery disease -- was co-chaired by neurologist Thomas Brott, MD, of the Mayo Clinic in Jacksonville, Fla., and cardiologist Jonathan Halperin, MD, of Mount Sinai Medical Center in New York City.

In terms of treating symptomatic carotid stenosis, the guidelines cited both carotid endarterectomy and carotid stenting as viable options.

The authors recommended carotid endarterectomy for patients at low to average surgical risk who have had a nondisabling ischemic stroke or transient cerebral ischemic symptoms -- if the diameter of the lumen of the ipsilateral internal carotid artery is reduced more than 70% as seen on noninvasive imaging or 50% according to catheter angiography -- and the expected rate of perioperative stroke or mortality is less than 6%.

Asymptomatic patients can undergo revascularization, a decision that "should be guided by an assessment of comorbid conditions, life expectancy, and other individual factors and should include a thorough discussion of the risks and benefits of the procedure with an understanding of patient preferences," the authors wrote.

They stated that it is reasonable to choose surgery over stenting for older patients, especially when arterial pathoanatomy is not suited for endovascular intervention.

On the other hand, stenting is a reasonable choice over surgery when revascularization is indicated in patients with neck anatomy unfavorable for arterial surgery, they wrote.

In patients who have a high risk of complications from either method of revascularization, the effectiveness of either option over medical therapy alone has not been well established, the authors cautioned.

The joint guidelines made dozens of additional recommendations for managing patients with extracranial carotid or vertebral atherosclerosis:

• Duplex ultrasonography performed by a qualified technologist in a certified laboratory is recommended as the initial diagnostic test to detect hemodynamically significant carotid stenosis.
• It is reasonable to repeat duplex ultrasonography annually to assess the progression of disease and response to treatment in patients with atherosclerosis who have had stenosis greater than 50% detected previously. Longer intervals or termination of surveillance may be appropriate once stability has been established.
• When the results of initial noninvasive imaging are inconclusive, other methods can be useful, including magnetic resonance angiography or CT angiography.
• Antihypertensive treatment is recommended for patients with hypertension and asymptomatic extracranial carotid or vertebral atherosclerosis to a target below 140/90 mm Hg.
• Treatment with statins is recommended for all patients with extracranial carotid or vertebral atherosclerosis to reduce LDL cholesterol to below 100 mg/dL. Treatment to a target near or below 70 mg/dL is reasonable for patients with extracranial carotid or vertebral atherosclerosis who have an ischemic stroke.
• Aspirin therapy (75 to 325 mg daily) is recommended for patients with obstructive or nonobstructive atherosclerosis that involves the extracranial carotid and/or vertebral arteries for prevention of MI and other cardiovascular events, although benefit has not been established for stroke prevention in asymptomatic patients.
• In patients with extracranial carotid or vertebral atherosclerosis who have sustained an ischemic stroke or transient ischemic attack, antiplatelet therapy with aspirin alone, clopidogrel (Plavix) alone, or the combination of aspirin and extended-release dipyridamole is recommended over the combination of aspirin and clopidogrel.

The guideline authors pointed out that many of the recommendations were made on the basis of consensus because of the lack of definitive evidence.

"There are vast opportunities for future research," they commented.

"The most pressing question is how either technique of revascularization compares with intensive contemporary medical therapy, particularly among asymptomatic patients, and a direct comparative trial should include a sufficiently broad range of patients to permit meaningful analysis of subgroups based on age, sex, ethnicity, and risk status," the authors wrote.

They noted that large gaps in the knowledge of vertebral artery disease will be more difficult to address because of its relative infrequency compared with carotid stenosis.