Intravascular ultrasound assessment of atherosclerotic plaque in the aorta.

Background: Intravascular ultrasound (IVUS) has been used for assessment of the coronary arteries. However, few IVUS studies have been reported on the aorta.

Materials And Methods: To assess the presence of atherosclerotic disease in the aorta by the use of IVUS, 29 patients with heart disease (24 men and 5 women; mean age, 61+/-11 years) including ischemic heart disease (n=21) and valvular disease or dilated cardiomyopathy (n=8) were enrolled in the study. An IVUS catheter was inserted through the femoral artery, and IVUS images were obtained in the descending aorta (DA) at the level of the pulmonary artery bifurcation, and in the proximal and distal regions of the abdominal aorta (AA) at the level of the renal artery bifurcation. Percent plaque area (%PA) was calculated as vessel cross-sectional area surrounded by media minus lumen cross-sectional area divided by vessel cross-sectional area.

Results: %PAs differed significantly between the three aortic levels: DA, 14.9+/-5.5%; proximal AA, 19.0+/-6.9%; and distal AA, 28.3+/-9.7% (p<0.05). However, PA did not differ significantly between the three levels (DA, 94.7+/-38.0 mm2; proximal AA, 90.9+/-35.0 mm2; distal AA, 79.7+/-32.3 mm2). %PA and PA in the DA and proximal AA correlated with age (r=0.39-0.46, p<0.05), but not with coronary angiography findings or multiple risk factors.

Conclusions: The aortic plaque is clearly observed by IVUS. The plaque is diffuse at the 3 levels, had little relationship with risk factor of arteriosclerosis or coronary artery disease, and aging affected the increase of plaque.