USPSTF Recommends Against Routine Screening for Carotid Artery Stenosis

Primary care physicians should not screen for asymptomatic carotid artery stenosis, or CAS, in the general adult population, according to the U.S. Preventive Services Task Force, or USPSTF. The recommendation and supporting documents are available online.

The new guidance is a grade "D" recommendation, which means that the USPSTF recommends against the service because there is a "moderate or high certainty that the service has no benefit or that harms outweigh the benefits." In this case, the USPSTF found that although stroke is a leading cause of death and disability in the United States, only a small number of disabling, unheralded strokes are due to CAS. Moreover, said the task force, in the general population, the potential harms of detection and early intervention outweigh any possible benefits they might bring.

The reliability of the most feasible screening test for severe CAS -- carotid duplex ultrasonography -- has not been established; such testing often yields false-positive results. Positive results are most often confirmed by digital subtraction angiography, which itself can cause strokes in certain patients. Other confirmatory tests, such as magnetic resonance angiography, may be inaccurate. Thus, some individuals with false-positive results will receive unnecessary invasive carotid endarterectomy surgery.

In addition, despite good evidence showing that carotid endarterectomy among selected high-risk clinical trial participants with asymptomatic severe CAS can reduce the five-year absolute incidence of all strokes or perioperative deaths by about 5 percent, the projected benefits among the general primary care population were judged to be "no greater than small," said the task force.

According to the recommendation, in excellent surgical care settings with low rates of complications, screening for CAS may benefit patients who are at high risk for stroke. However, identifying patients who are at high risk for stroke but who are not at risk for surgical complications is difficult. Even in such settings, the procedure is associated with a 30-day stroke or mortality rate of about 3 percent.

Risk factors for CAS include older age, male gender, hypertension, smoking, hypercholesterolemia and heart disease. Instead of screening for CAS in the general adult population, the USPSTF recommends that physicians screen their patients for hypertension, hyperlipidemia and smoking. For patients who are at increased risk of heart disease, physicians should discuss aspirin chemoprevention.

It's worth noting that this USPSTF recommendation applies only to adult patients who have no neurological signs or symptoms, including a history of transient ischemic attacks, or TIAs, or stroke. Eligible patients who have a carotid TIA should be evaluated immediately for consideration of carotid endarterectomy.