Jul 12, 2018
There is still not enough evidence to recommend for or against using the ankle-brachial index (ABI) test to screen for peripheral arterial disease (PAD) in adults without symptoms, such as claudication in the lower leg, a US Preventive Services Task Force (USPSTF) report concludes.
“In asymptomatic folks we did not find evidence that the benefits of screening [with ABI] outweighed any potential harms,” task force member C. Seth Landefeld, MD, from the University of Alabama at Birmingham, summarized to theheart.org | Medscape Cardiology.
“It doesn’t mean that [such screening isn’t warranted]; it’s just that we didn’t find compelling evidence” for it.
Instead, clinicians should “focus on evaluating cardiovascular risk with well-established tools such as the Pooled Cohort Equations,” he said, “and then implement previously recommended interventions, such as blood pressure control, smoking cessation, or preventive statins or aspirin. These things do have very definite benefits.”
“I want to emphasize that this is not a recommendation against screening for PAD; it’s a recommendation that there’s insufficient evidence for across-the-board screening,” echoed Mary M. McDermott, MD, from Northwestern University Feinberg School of Medicine, Chicago, Illinois, who cowrote an editorial about the statement.
“Screening specifically applies to people who don’t have leg symptoms,” she stressed in an interview with theheart.org | Medscape Cardiology. But “most people with PAD have leg symptoms if you look carefully.”
“PAD is common and it’s often unrecognized, undiagnosed, and undertreated,” she said. “But a lot of that has to do with the fact that we don’t ask patients carefully enough about leg symptoms that may indicate PAD.”Patients who have leg symptoms “should all be tested with ABI,” she noted.
Five New Studies, No Strong Evidence
PAD, which is a manifestation of systemic atherosclerotic disease, not only can impair walking ability but also lead to infection and amputation in severe cases, USPSTF chair Susan J. Curry, PhD, from the University of Iowa in Iowa City, and colleagues note.
Because a low ABI is associated with an increased risk for cardiovascular disease (CVD) events, screening asymptomatic adults for PAD with the ABI might reduce morbidity or mortality from PAD or CVD.
To update its 2013 report, the task force identified five studies published between 2012 and 2017 that screened for PAD in a total of 5864 asymptomatic participants with no known cardiovascular disease.
One study, which compared the diagnostic accuracy of ABI vs the gold standard, MRI, found that ABI had low sensitivity (7% to 34%) and high specificity (96% to 100%).