Feasibility of targeting atherosclerotic plaques by high-intensity-focused ultrasound: an in vivo study.

Purpose: To investigate the feasibility and acute safety of targeting atherosclerotic plaques by high-intensity-focused ultrasound (US) in vivo through a noninvasive extracorporeal approach.

Materials And Methods: Four swine were included in this prospective study, three of which were familial hypercholesterolemic swine. The procedure was done under general anesthesia. After US identification of atherosclerotic plaques within the femoral arteries, plaques were targeted by high-intensity focused US with an integrated dual-mode US array system. Different ablation protocols were used to meet the study objectives, and animals were then euthanized at different time points. Targeted arterial segments were stained by hematoxylin and eosin for histopathologic examination. Numeric values are presented as means ± standard deviation.

Results: All swine tolerated the procedure well, with no arterial dissection, perforation, or rupture. Discrete lesions were detected in the first two swine, measuring 0.54 mm ± 0.10 and 0.25 mm ± 0.03 in cross-sectional dimensions in the first and 0.50 mm ± 0.12 and 0.24 mm ± 0.15 in the second. Confluent ablation zones were identified in the last two swine, measuring 6.92 mm and 0.93 mm in the third and 2.97 mm and 2.52 mm in the fourth. Lesions showed necrotic cores and peripheral reactive inflammatory infiltration. The endothelium overlying targeted arterial segments remained intact.

Conclusions: The results demonstrate the feasibility and acute safety of targeting atherosclerotic plaques by high-intensity-focused US in vivo. Further long-term studies are needed to assess how induction of these lesions can modify the progression of atherosclerotic plaques.