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.

She estimated that three out of every 10 people who get the test will have a vascular age that is higher than their chronological age. These people are then treated aggressively for preventive care.

For the study, Neri and colleagues assessed the carotid arteries of 26 patients within 30 days of admission for a first-time STEMI. Patients had no prior history of coronary artery disease, diabetes, peripheral, or cerebrovascular disease.

Researchers defined a vascular age for each patient based on an algorithm derived from the Atherosclerosis Risk in the Communities (ARIC) database and then re-calculated the Framingham risk score with the addition of the vascular age.

While the mean patient age was 52, the mean vascular age was nearly 80. Using the Framingham risk score, only two out of the 26 patients were considered at high risk for a heart attack. Adding the CIMT assessment boosted that number to 11. Neri said they are still analyzing the data to determine what other factors might help identify the remaining nine patients who had a STEMI.

The cohort as a whole had a mean 10% risk of a heart attack based on the Framingham score, which increased to 17% with the addition of the CIMT assessment.

“Our results suggest that a CIMT assessment may help improve risk stratifying in asymptomatic patients with a strong family history of heart disease and one or two risk factors,” Neri concluded.

She added that patients who see they have an older vascular age are often much more motivated to change their lifestyle and comply with medication adherence.

Primary source: Preventive Cardiovascular Nurses Association
Source reference: Neri L, et al “The use Of carotid media thickness in predicting ST elevation myocardial infarction” PCNA 2012; Abstract 8.