Objectives: To serially investigate the relationship between vasa vasorum (VV) proliferation and plaque progression in vivo, and the effects of atorvastatin on VV and atherosclerosis as assessed by contrast-enhanced ultrasound (CEUS) and intravascular ultrasound (IVUS) imaging.
Methods: Carotid atherosclerosis was induced in rabbits with a high-cholesterol diet for 20 weeks and balloon injury. At week 16, following the imaging of the right common carotid arteries by CEUS and IVUS, 20 rabbits were randomised into a control or atorvastatin group (2 mg/kg/day). At week 20, CEUS and IVUS were repeated. Normalised maximal video-intensity enhancement (MVE) was calculated to quantify the density of VV. Plaque volume was determined by IVUS.
Results: When compared with the control group, lipid levels were not significantly lower following 4 weeks of atorvastatin administration. The increases in the normalised MVE over time were greater in the control group than in the atorvastatin group (p=0.001). The increase in plaque volume from 16 to 20 weeks was significantly greater in the control group than in the atorvastatin group (p=0.001). There was a positive relationship between changes in normalised MVE and plaque volume (r=0.72, p=0.002).
Conclusions: There was a positive correlation between VV density and plaque progression. Atorvastatin significantly inhibits the development of adventitial VV and progression of atherosclerosis independent of lowering the cholesterol level.