LETTER
The Role of Carotid Bruit in Screening for Carotid Stenosis
Thomas Rea, MD
15 October 1997 | Volume 127 Issue 8 (Part 1) | Page 657
TO THE EDITOR:
I concur with Lee and colleagues' [1] careful evaluation and discussion of the cost-effectiveness of screening for carotid stenosis in asymptomatic persons. However, I wonder whether the authors considered the clinical question of importance: Would screening only persons with carotid bruits be cost-effective? Auscultation of the carotid arteries is a simple, safe, and inexpensive maneuver. In addition, the presence of a neck bruit is a fairly reproducible finding on physical examination [2]. Thus, could the presence of a carotid bruit initially and appropriately narrow the asymptomatic target population?
In a population similar in age to that of Lee and colleagues' theoretical study group, Zhu and Norris [3] found that the presence of a neck bruit positively predicted severe stenosis (defined as >75% stenosis) in 17% of asymptomatic persons. In the same study, bruit predicted moderate (defined as >35% stenosis) or severe stenosis in 55% of asymptomatic persons. Unfortunately, Zhu and Norris did not study a group with stenosis of 60% or greater, a group studied by Lee and colleagues. However, the prevalence of bruit in such a group may approach the 40% that Lee and associates cited as necessary for cost-effectiveness.
Another issue of concern in using auscultation as an initial screening tool would be the exclusion of persons with significant stenosis but no bruit. In the Asymptomatic Carotid Atherosclerosis Study [4], 75% of patients with significant disease (
60% stenosis) had an ipsalateral bruit and 43% had a contralateral bruit. A conservative conclusion would be that 80% of patients with significant disease had a bruit, leaving 20% wrongly excluded from further screening as dictated by auscultation.
Other studies [5] have questioned the accuracy of the presence of carotid bruit. Thus, I would appreciate the authors' thoughts and guidance on this topic. If initial screening incorporated auscultation, could cost-effectiveness improve to an acceptable level while still allowing inclusion of most eligible candidates?
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Author and Article Information
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Seattle, WA 98104
1. Lee TT, Solomon NA, Heidenreich PA, Oehlert J, Garber AM. Cost-effectiveness of screening for carotid stenosis in asymptomatic persons. Ann Intern Med. 1997; 126:337-46.
2. Chambers BR, Norris JW. Clinical significance of asymptomatic neck bruits. Neurology. 1985; 35:742-5.
3. Zhu C, Norris JW. Role of carotid stenosis in ischemic stroke. Stroke. 1990; 21:1131-4.
4. Endarterectomy for asymptomatic carotid artery stenosis. JAMA. 1995; 273:1421-8.
5. Ziegler DR, Zileli T, Dick A, Selbaugh JL. Correlation of bruits over the carotid artery with angiographically demonstrated lesions. Neurology. 1971; 21:860-5.
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