Carotid Test Boosts Cardiac Risk Prediction

Determining one's vascular age via an ultrasound of the carotid intima-media thickness (CIMT) can help triage the so-called "worried well," a small study found.

In an effort to test the robustness of CIMT-adjusted risk, Lori Neri, CRNP, CLS, and colleagues from The Heart Care Group in Allentown, Pa., assessed the carotids of 26 patients with a first-time ST elevation myocardial infarction (STEMI) and no known prior cardiovascular disease.

They found that the CIMT-adjusted vascular age was significantly higher than the chronological age (79.5 versus 52.8 years, P<0.001).

In addition, although the Framingham risk score put 7.7% of these patients into a high-risk category, when the CIMT-adjusted age was added, 42.3% were classified as high-risk, Neri reported at the Preventive Cardiovascular Nurses Association meeting in National Harbor, Md.

STEMI patients are typically in their early 50s, generally younger than those with acute coronary syndromes, and they may not appear as obvious candidates to be at risk for heart disease.

"That's why it's important to find a way to identify those whose Framingham score does not categorize them as high risk but who in fact may have an elevated risk," Neri told MedPage Today.

The American Heart Association/American College of Cardiology guidelines say it's reasonable to use CIMT assessment in asymptomatic adults at intermediate risk (class IIa, level of evidence B).

The guidelines state that CIMT has been independently associated with future risk for ischemic events in middle-age individuals and that the risk is linearly associated with the artery thickness.

Neri, who is the director for the Center of Cardiac Risk Prevention at The Heart Care Group, said she gets a "fair amount of the worried well" in the clinic. These are people in their 50s with a strong family history of heart disease who are concerned about their own risk.

These people always undergo the usual risk assessment tests. If there is something that stands out, such as an abnormally high cholesterol, Neri will recommend the CIMT scan.

Co-author Martin E. Matsumura, MD, had previously shown that the Framingham risk score misses about 60% of patients presenting with a first STEMI. In this group, Matsumura said, the Framingham score "overemphasizes age as a risk factor."

The CIMT test uses an ultrasound probe to image the inner lining of the carotid arteries for subclinical plaque. Software calculates the vascular age based on the thickness of the lining.

"It's a sensitive and reproducible test," Neri said, adding that operator experience is crucial to obtaining high-quality results.

Insurance does not cover the test, but patients can have it done at Neri's clinic for under $50. "We started out charging $199, but continually dropped the price because we feel strongly about it's use and importance," Neri said.