In recent recommendations, the U.S. Preventive Services Task Force (USPSTF) has ruled against adding new risk factors—such as ankle-barchial index (ABI)—to supplement traditional risk factors used in screening for heart disease.

USPSTF looked at the current evidence to determine if screening people without signs or symptoms of peripheral artery disease (PAD) with the ABI can help prevent heart attack, stroke, or PAD complications. PAD is a condition where blood flow to the limbs, especially the legs, is reduced due to a narrowing and hardening of the arteries. PAD can cause leg and foot pain when resting or walking, poor wound healing, tissue damage, and loss of limbs. People with PAD are also more likely to have a CVD event, such as heart attack and stroke. People with PAD can also have no symptoms. Based on its review, the task force found that there is insufficient evidence to recommend for or against screening for PAD and cardiovascular disease risk assessment with the ABI in people without signs or symptoms.

“The ABI is a way of taking blood pressure using readings from both the ankle and the arm to determine risk of blocked vessels in the leg,” says task force member Alex Krist, MD, MPH. “For people with symptoms of PAD, the ABI can be used for diagnosis. However, more evidence is needed to determine if the ABI can accurately identify PAD in people without signs or symptoms.”

Meanwhile, USPSTF also reviewed whether adding three nontraditional risk factors to traditional risk models can effectively improve risk assessment for CVD. Traditional risk factors are based on age, race/ethnicity, sex, diabetes, smoking status, cholesterol levels, and blood pressure. The task force looked at the evidence for three nontraditional risk factors: the ABI, high-sensitivity C-reactive protein (hsCRP), and coronary artery calcification (CAC) score. The body found that there is not enough evidence to recommend for or against assessing CVD risk in adults with these nontraditional risk factors, along with traditional risk factors, to help prevent heart attack or stroke.

“While there is some evidence that ABI, CAC, and hsCRP can slightly improve clinicians’ ability to define risk, the amount of improvement is not large or precise enough to help clinicians make better treatment or care decisions to prevent heart attack or stroke,” says task force member Seth Landefeld, MD. “More research is needed to understand the benefits and harms of using these three nontraditional risk factors in addition to the traditional risk factors for assessing CVD risk.”

In its rationale for rejecting the nontraditional risk factors, USPSTF states that the main potential harm in adding them is low-dose radiation exposure from CAC score measurement. Other harms include false-positive test results and subsequent invasive diagnostic procedures.

The public has the opportunity to comment until Feb. 12.