Rhythmic structures and atherosclerosis in the aorta.

The presence of so-called rhythmic structures (RS) or 'wave-lines' was studied in aortic specimens from 380 males and 201 females of ages between 10 and 39 years, from Malmö, Sweden, Prague, CSSR, and Yalta, Ukraine. RS were found in 56% of the males and 54% of the females, but with some sex differences between cities: in Malmö they were more frequent in males, in Yalta in females, but in Prague no sex difference was found. RS were significantly more common in the abdominal than in the thoracic part (68% and 32%, respectively). All stages of transformation of rhythmic structures into fibrous plaques can be found. In aortas with RS, fibrous plaques were statistically more frequent than in aortas without RS, and the fibrous plaques were mostly found in the same location as the RS.