Ultrasound may fill void when traditional tools don’t suffice

An automated ultrasound device for imaging peripheral arteries may provide a way to identify people with subclinical atherosclerotic plaque in populations not well served by risk-factor tools, according to a study published Jan. 12 in Global Heart.

Ram Bedi, PhD, a bioengineer and affiliate assistant professor at the University of Washington in Seattle, and colleagues conducted the feasibility study to determine if B-mode ultrasound might have a role in low- and middle-income countries. Some of those countries lack the infrastructure and trained staff for identifying and treating asymptomatic people with atherosclerotic cardiovascular disease. In addition, their populations may not match populations studied to design and validate existing risk-assessment tools.

The study design included four patient groups: two in India, one in Toronto and one in Texas. The North American groups served as a reference. For the Indian portion of the study, 941 asymptomatic participants from one town and one city received ultrasound imaging of four arterial beds (carotid and iliofemoral) by radiology residents who were trained on the spot.

The ultrasound devices had built-in automated functions. They used the Fuster-Narula (FUN) score to summarize results from 3D data on the ultrasound exams.

Overall, 23.8 percent of the Indian participants had atherosclerotic plaque detected by ultrasound. In 11.4 percent, only the carotid arteries were involved; in 5 percent, only the iliofemoral arteries were involved; and 7.6 percent, they detected plaque in both carotid and iliofemoral arteries.

The 481 North American volunteers were on average older than the Indian volunteers, at about 59 vs. 44 years old. Carotid plaque was present in 42 percent of the North American group. Based on risk factors in the Adult Treatment Panel (ATP) III guidelines, 35 percent of those with carotid plaque would not qualify for lipid-lowering treatment. Under the more recent guidelines, 14 percent did not qualify.

“It seems that plaque information from ultrasound images may serve as a guide for initiating medical intervention regardless of the availability or knowledge of traditional risk factors,” Bedi et al wrote. “Our results further suggest that not only in low- and middle-income countries, but even in the developed nations, ultrasound images may help refine strategies for medical intervention.”

They acknowledged that the American Heart Association/American College of Cardiology 2013 guidelines recommend against carotid intima-media thickness testing, which is a component of the data used for calculating the FUN score. They pointed out that the guideline authors didn’t consider plaque findings in their review, though. They added that in developing countries “an alternative strategy for identifying high-risk individuals may not be out of place.”