Aug. 17, 2020, 08:00 am News Staff – Asymptomatic carotid artery stenosis is one of several factors for increased stroke risk. Although relatively uncommon, the prevalence of asymptomatic CAS increases with age, and research has suggested that the annual risk of stroke for patients with severe CAS who don't receive optimal cardiovascular preventive care is between 2% and 4%.
On Aug. 4, the U.S. Preventive Services Task Force issued a draft recommendation statement and draft evidence review on screening individuals with no history or signs or symptoms of a blocked artery in the neck for CAS.
Based on the available evidence, the task force recommends against screening for asymptomatic CAS in the general population. This is a "D" recommendation, and applies to adults without a history of stroke, transient ischemic attack, or other signs or symptoms of stroke.
"The task force wants to help prevent people from having a stroke, but screening for carotid artery stenosis in those without symptoms of a blocked artery is not an effective way to do so," said USPSTF member Michael Barry, M.D., in a news release. "The evidence shows there are no benefits and there are serious harms, so we recommend against screening."
The draft recommendation reaffirms the findings of the task force's 2014 final recommendation statement on the topic. which also recommended against screening for asymptomatic CAS. The AAFP supported the 2014 recommendation.
For the latest draft recommendation, the USPSTF chose to use a reaffirmation deliberation process in which only a very high level of evidence would justify a change in the recommendation's grade. Using this process, the task force concluded with moderate certainty that the harms of screening for asymptomatic CAS outweigh the benefits.
To update its previous recommendation, the USPSTF commissioned a systematic evidence review of studies published between Jan. 1, 2014, and Feb. 14, 2020. Although the task force members identified two trials that compared carotid revascularization with best medical treatment for asymptomatic CAS and seven studies that examined the harms associated with revascularization of asymptomatic CAS, they were unable to identify any eligible studies that directly examined the benefits or harms of screening.
"Population-based screening trials addressing the benefits and harms of screening for carotid artery stenosis have never been conducted," the task force concluded, adding that since the last literature review, "little new indirect evidence has emerged that answers the critical question of whether carotid revascularization is superior to contemporary best medical management."
The USPSTF noted that although it recommends against screening for asymptomatic CAS, it has issued several other recommendations to help clinicians and patients reduce stroke risk through other methods, including
"The best way to prevent stroke is to focus on things we know work," added task force member Aaron Caughey, M.D., M.P.P., M.P.H., Ph.D., in the news release. "This includes controlling high blood pressure and cholesterol, not smoking, maintaining a healthy weight, being physically active, and eating a healthy diet."
The USPSTF is accepting comments on the draft recommendation statement and draft evidence review on screening adults for asymptomatic CAS until 11:59 p.m. EDT on Aug. 31. All comments received will be considered as the task force prepares its final recommendation.
The AAFP will review the USPSTF's draft recommendation statement and supporting evidence and will provide comments to the task force. The Academy will release its own recommendation on the topic after the task force finalizes its guidance.