Natural history of aortic arch atherosclerotic plaque.

To define the natural history of aortic arch plaque, we used B-mode ultrasonography to perform sequential study of the aortic arch. Eighty-nine patients were studied for up to 18 months. There was no change in 67% of total plaques; 77% of simple plaque (<4 mm) and 48% of complex plaque (> or =4 mm) did not progress. Atherosclerosis of the aortic arch can be sequentially studied with B-mode ultrasonography, and most of these lesions remain unchanged after up to 18 months of observation.