USPSTF finalizes recommendation against ultrasound screening to prevent stroke

The United States Preventive Services Task Force has finalized its draft recommendation against ultrasound carotid artery stenosis screening as a way of preventing stroke.

The recommendation was published July 8 in the Annals of Internal Medicine. According to USPSTF, while the use of ultrasound to test for carotid artery stenosis (CAS) has high sensitivity and specificity, there are no validated, reliable tools that can determine who is at increased risk for CAS, or for stroke when CAS is present.

USPSTF also pointed out that ultrasound screening yields many false-positive results in the general population, which has a low incidence of the condition.

Stroke risk could potentially be reduced through the use of screening ultrasound by enabling clinicians to detect it earlier and perform interventional procedures like carotid endarterectomy (CEA). But, according to USPSTF, "[a]dequate evidence indicates that both the testing strategy for carotid artery stenosis and treatment with CEA can cause harms."

For example, CEA is associated with a 30-day stroke or mortality rate of approximately 2.4 percent, with reported rates as high as 5 percent in low-volume centers, and 6 percent in some states. And myocardial infarctions are reported in 0.8 percent to 2.2 percent of patients after CEA.

"The overall magnitude of harms of screening and subsequent treatment of asymptomatic carotid artery stenosis is small to moderate depending on patient population, surgeon, center volume, and geographic location," according to USPSTF, which concluded that the harms of CAS outweigh the benefits.

In an editorial also published in Annals, Larry Goldstein, M.D., of Duke University Medical Center, wrote that while the data clearly supports the USPSTF recommendation against population screening for asymptomatic CAS, these kinds of screening exams take place throughout the U.S. at health fairs and in other settings.

He noted that the American Academy of Neurology, through the Choosing Wisely initiative, recommends against the use of endarterectomy for asymptomatic carotid stenosis, unless the complication rate is low. Goldstein suggested that an additional recommendation, which could be forthcoming in the future, should include a warning against population screening for asymptomatic carotid artery stenosis.

"In the interim, potential consumers of these services should be aware that the test is unlikely to prevent them from having a stroke or to lead to improvements in their health," he said.

Using advanced imaging after the onset of acute stroke does not help physicians identify patients who benefit from a clot-removal procedure, according to results from the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) Trial published in February 2013.

Still, magnetic resonance imaging can, by identifying vulnerable carotid plaque characteristics, help predict the likelihood of cardiovascular events in persons without a history of cardiovascular disease, according to research published this past March.

To learn more:
- see the USPSTF recommendation
- read the accompanying editorial