Susceptibility to atherosclerosis in aortas and coronary arteries of swine with von Willebrand's disease.

The development of coronary and aortic atherosclerosis was determined after balloon catheter injury of coronary arteries and administration of an atherogenic diet in normal pigs and pigs that were homozygous and heterozygous for von Willebrand's disease. Coronary atherosclerosis developed to a similar degree in all three phenotypic groups. The mean intimal thickness at the site of maximal thickness in ballooned vessels was .51 mm in the normal pigs, .67 mm in carrier pigs, and .55 mm in bleeder pigs. The intimal thickness of non-ballooned vessels was .28 mm in normal pigs, .28 mm in carrier pigs, and .35 mm in bleeder pigs. Fibrous lesions of atherosclerosis covered an average of 3.88% of the aorta in normal pigs, 2.83% in carrier pigs, and 2.37% in bleeder pigs. The difference between the aortic lesions of normal animals and bleeders was significant (P less than .05). Absence of von Willebrand factor was associated with limited resistance to atherosclerosis in the aortas of experimental pigs but did not affect the development of atherosclerosis in either ballooned or nonballooned coronary arteries. These findings suggest, first, that von Willebrand factor function is not essential to the development of the atherosclerotic lesion in this model and, second, that the role of the von Willebrand factor in the development of atherosclerosis is complicated and appears to involve interaction with variables not yet defined.