Detection of subclinical atherosclerosis in peripheral arterial beds with B-mode ultrasound: A proposal for guiding the decision for medical intervention and an artifact-corrected volumetric scoring index

Objectives: To assess subclinical atherosclerotic cardiovascular disease (ASCVD) using B-mode ultrasound, with special emphasis on the incremental value of performing imaging in multiple peripheral arteries, and to compare imaging findings with traditional risk factors for medical intervention eligibility. Methods: Data from 2 asymptomatic cohorts from India with unknown ASCVD risk factors were compared to 2 cohorts from North America with known ASCVD risk factors. Carotid and iliofemoral arteries of the Indian cohorts were examined with automated ultrasound in a high-pace environment by non-experts. A simplified metric of atherosclerotic disease burden (FUster-Narula or FUN Score) was developed from 3D imaging data by summing intima-media volume (IMV) over 5-cm arterial segments. Effectiveness of ASCVD prevention guidelines to direct therapy was compared to results from direct imaging. Results: Of the 941 (mean age 44.27 ± 13.76 years, 34% female) enrollees from India, 224 (24%) demonstrated plaques in at least 1 of the 4 arterial sites examined; 107 (11%) had plaques in only the carotids, 70 (7%) in both the carotids and iliofemoral arteries, and 47 (5%) had plaques in only the iliofemoral arteries. Older age and male sex were associated with the presence of plaque, but association with systolic blood pressure was not observed. Data from 2 North American clinics (n = 481, mean age 59.68 ± 11.95 years, 39% female) showed that 203 subjects (42%) had carotid plaque; 82% of whom would not have qualified for lipid-lowering therapy under the Adult Treatment Panel (ATP) III Guidelines. Using the recently published ATP IV Guidelines, 33% of the individuals with carotid plaque would also have failed to qualify for treatment. Conclusions: B-mode ultrasound examination of bilateral iliofemoral arteries provided an incremental yield in identifying subclinical atherosclerotic disease compared to carotid evaluation alone. Ultrasound examination allowed improved identification of individuals who could be targeted for prophylactic medical intervention compared to ATP III and ATP IV Guidelines.