Study reveals high rate of questionable imaging in asymptomatic revascularization patients

A majority of Veterans Health Administration (VHA) patients who underwent carotid revascularization for asymptomatic carotid disease were diagnosed based on “uncertain” or “inappropriate” imaging, according to a study published in JAMA Internal Medicine.

Salomeh Keyhani, MD, department of medicine at the University of California San Francisco, and colleagues studied more than 4,000 VHA patients 65 years and older who underwent carotid revascularization between 2005 and 2009. All patients had no history of stroke or transient ischemic attack.

For each patient, the researchers determined the appropriateness of each patient’s carotid ultrasound by examining the indications. They found that more than 83 percent of the imaging was uncertain, more than 11 percent was inappropriate, and more than 5 percent were truly appropriate.

“Whereas most of the appropriate indications assigned to images were related to ocular disease,” the authors wrote. "The most common appropriate indication listed was follow-up within 2 years of carotid intervention. Carotid bruit and follow-up for established carotid disease were the most prevalent uncertain indications. Among the inappropriate indications, dizziness/vertigo, syncope, and blurred/change in vision were the most common.”

Keyhani et al. noted that national guidelines on carotid screening lack consistency.

“The US Preventive Services Task Force  has recommended against carotid screening in adult patients without a history of stroke or TIA in both its 2007 and updated 2014 guidance,” the authors wrote. “Other national guidelines favor imaging for some limited indications in patients with asymptomatic carotid disease (eg, those with established stenosis, carotid bruit, or multiple vascular risk factors) although these recommendations are based on expert opinion rather than robust evidence.”

The authors also noted that there is a “tension between appropriate screening and appropriate revascularization.”

“This clinical dilemma is the result of the chosen point of reference,” they wrote. “From an individual perspective, it may be beneficial to have screening that is not guideline based if that screening demonstrates a true positive abnormality that is amenable to an effective evidence-based intervention. From a societal perspective, screening all patients (including a patient who benefited) may not be beneficial (and thus not recommended) if the false-positive rate of the screening test is high or the evidence for intervention is weak. This tension between the individual perspective (which often does not include consideration of the harms of false-positive test results) and the societal perspective is at the root of many of the current national debates on screening.”

Keyhani and colleagues concluded that reducing inappropriate imaging could have multiple benefits, including a reduction in the number of patients undergoing intervention when they may not live long enough to actually benefit from the procedure. Updated guidelines and an increased use of decision support software were suggested as ways to achieve that goal.

“Given that carotid imaging is a fairly commonly ordered test, targeting carotid imaging using decision support tools to reduce inappropriate use may be a good approach to improve the value of health care without compromising quality,” the authors wrote.

The team added that its study did have limitations, including the fact that more than 98 percent of the patients evaluated were male. In addition, appropriateness was assessed by a panel, and disagreement among panelists would result in imaging being described as uncertain.