July 8th, 2014
USPSTF Finalizes Recommendations on Carotid Artery Stenosis Screening
Nicholas Downing, MD
The U.S. Preventive Services Task Force has recommended against screening for asymptomatic carotid artery stenosis in the general adult population (grade D recommendation). Published in the Annals of Internal Medicine, the statement reiterates the group’s 2007 guidance.
The harms of screening outweigh the benefits, the task force says. The groups notes that all screening strategies (e.g., ultrasonography, magnetic resonance angiography) “have imperfect sensitivity and could lead to unnecessary surgery and result in serious harms, including death, stroke, and myocardial infarction.”
The recommendation applies to adults without histories of transient ischemic attack, stroke, or other neurologic symptoms.
Ann Intern Med. Published online 8 July 2014 doi:10.7326/M14-1333
DETECTION
“Adequate evidence indicates that the accuracy of screening by auscultation of the neck is poor.”
SCREENING TESTS
“There is no evidence that screening by auscultation of the neck to detect carotid bruits is accurate or provides benefit.”
Ergo- what does one do upon auscultation of unilateral or bilateral bruits?
Excellent point. Why even bother listening for carotid bruits?
I completely agree that screening for carotid stenosis is of little or no value. This is based on the infrequent incidence of finding stenosis and the minimal value in surgery to treat stenosis.
That said, I believe that screening for the presence of plaque to help stratify risk and direct medical therapies is an important concept. MESA found that the carotid IMT was twice as predictive as all risk factors combined. The presence of plaque is more powerful than IMT. While carotid screening is not as powerful as coronary calcium, however when coronary calcium screening is not available, carotid plaque screening is a valuable tool in MI and stroke prevention.
So…under PATIENT POPULATION UNDER CONSIDERATION-
“A previous USPSTF review on the assessment of carotid intima–media thickness in 2009 found insufficient evidence to support its use as a screen for coronary heart disease risk. For this recommendation, the USPSTF did not review new evidence on ultrasonography to characterize carotid plaque structure or intima–media thickness and their association with cardiovascular disease events. However, clinicians considering using ultrasonography to characterize carotid plaque to stratify patient risk for cardiovascular disease should consider the same harms that the USPSTF evaluated for this recommendation (stroke, myocardial infarction, and death from CEA) because surgery may result from this screen.”
Cross reference with ACC/AHA Guidelines for Risk Assessment and Treatment of Blood Cholesterol(both 2013) advise use of ABI but against routine use CIMT with no mention of plaque detection/quantitation as basis for assessment or intervention.
I would agree with correlation of carotid plaque detected by ultrasonography and stroke and MI events- but a “review gap” does exist so as to include or exclude plaque detection as an Optional Screening Test(see Table 6 J Am Coll Cardiol. 2014;63(25_PA):. doi:10.1016/j.jacc.2013.11.005).