Use of portable B-mode ultrasound to examine the iliofemoral and carotid arteries enabled the identification of more subclinical atherosclerotic disease compared with carotid evaluation alone.
B-mode ultrasound also was associated with improved identification of individuals who are appropriate targets for prophylactic medical intervention compared with risk factor-based guidelines, according to a new report.
Ram Bedi, PhD, MBA, affiliate assistant professor in the department of bioengineering at the University of Washington, Seattle, and colleagues compared two asymptomatic cohorts from India with unknown atherosclerotic CVD risk factors vs. two cohorts from North America with known atherosclerotic CVD risk factors.
The Indian cohorts (n=941; mean age, 44 years; 34% women) had carotid and iliofemoral artery examination with automated ultrasound (CardioHealth Station, Panasonic Healthcare Co.) by nonexperts. To serve as a reference for comparison to the data from the Indian cohorts, atherosclerotic CVD risk factors and carotid ultrasound examination data were obtained from 481 asymptomatic patients (mean age, 60 years; 39% women) at clinics in Toronto and Richmond, Texas.
The researchers developed a simplified metric of atherosclerotic disease burden (Fuster-Narula [FUN] Score) from the imaging data, and compared imaging results with the effectiveness of atherosclerotic CVD-prevention guidelines to direct therapy.
In the Indian cohorts, 24% had plaques in at least one of the four arterial sites examined, 11% had plaques only in the carotids, 7% had plaques in the carotids and the iliofemoral arteries, and 5% had plaques only in the iliofemoral arteries.
Older age and male sex, but not systolic BP, were associated with presence of plaque, according to the researchers.
“Our study shows that automation in ultrasound technology allows even nonexpert users to rapidly evaluate the presence of subclinical atherosclerosis in a large population,” Bedi and colleagues wrote. “Detection of subclinical atherosclerosis is further enhanced by inclusion of the iliofemoral artery examination.”
In the North American cohorts, 42% of individuals had carotid plaque as measured by B-mode ultrasound. The researchers determined that, according to the 2001 National Cholesterol Education Program Adult Treatment III (ATP III) guidelines, 82% of those with carotid plaque would not have qualified for lipid-lowering therapy, and according to the 2013 American College of Cardiology/American Heart Association Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults, 33% of those with carotid plaque would not have qualified for lipid-lowering therapy.
“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,” the researchers wrote. “Our results further suggest that not only in low- and middle-income countries, but even in the developed nations, ultrasound may help refine strategies for medical intervention.”
Weakness of approach
In a related editorial, Tasneem Z. Naqvi, MD, wrote that the study “puts into perspective the weakness of a risk factor-based approach to identifying patients with subclinical atherosclerosis who are more likely to develop CV events.
“We need to ponder whether treating nearly 50% of the adults on statins using a risk-scoring algorithm in the United States is more appropriate vs. treating only those who have subclinical atherosclerosis on the basis of a comprehensive, readily available, inexpensive and simple screening method,” Naqvi, professor of medicine at Mayo Clinic College of Medicine, Scottsdale, Ariz., wrote.
For more information:
Bedi R. Global Heart. 2014;9:367-378.
Naqvi TZ. Global Heart. 2014;9:379-380.
Disclosure: Panasonic Healthcare Co. loaned the ultrasound equipment and provided technical support for the study. See the full study for a list of the researchers’ relevant financial disclosures. Naqvi reports no relevant financial disclosures.