Should adults be screened to detect asymptomatic carotid artery stenosis?

The use of duplex ultrasonography to detect clinically significant carotid artery stenosis in asymptomatic patients is not helpful and is likely to cause harm (grade D recommendation). Widespread screening leads to a significant number of false positive results, which in turn lead to further testing or treatment that can cause harm. There is no research showing that this type of screening leads to better outcomes. (LOE = 5)

U.S. Preventive Services Task Force. Screening for carotid artery stenosis: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2007;147:854-9. Wolff T, Guirguis-Blake J, Miller T, Gillespie M, Harris R. Screening for carotid artery stenosis: An update of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med 2007;147:860-70.  [PMID:18087056]

Practice guideline

Government

Various (guideline)

In the United States, enterprising clinicians with ultrasound machines travel from city to city offering, for a price, to ultrasound the carotid arteries of people without symptoms of transient ischemia or a history of stroke. The sensitivity (94%) and the specificity (92%) of carotid duplex ultrasound to detect stenosis of 60% or more is fairly good. However, given a prevalence rate of carotid artery stenosis of 1% to 5% for every 100,000 patients screened, between 7600 and 7920 patients will be incorrectly told they have carotid artery stenosis and sent either for further testing with angiography, which has its own risk of inducing stroke, or unnecessary surgery. There is no direct evidence that this type of screening reduces fatal or nonfatal stroke. In this general population, carotid endarterectomy may produce a slight benefit that is nearly outweighed by the increase in stroke (up to 6%) the procedure causes.