Prevention of platelet aggregation by dietary polyunsaturated fatty acids in the biodegradable polyurethane vascular prosthesis: an experimental model in pigs.

A 6-7 cm long degradable polyurethane vascular prosthesis was implanted in the infrarenal aorta of 25 young growing pigs, sacrificed from day 30 to 365 to study the processes of degradation and tissue growth, the characteristics of prosthetic substitutes and the incidence of thrombosis. Ten animals were used as controls and 15 were fed with cod liver oil (25 ml twice daily). Aortography performed at day 30, 60 and 90 showed 100% thrombosed implants in the controls, while in the lipid diet fed animals there was 100% patency. At graft retrieval, there were 7 patent grafts out of 9 in the cod liver oil fed animals. Laboratory tests indicated that the lipid diet rich in n-3 polyunsaturated fatty acids induces significant modifications of lipid metabolism preventing platelet aggregation. These data correlate well with findings of the morphological studies showing that all patent prostheses are lined with tissues similar to the endothelium of the native aorta with a mid layer made of circular and longitudinal smooth muscle cells well differentiated at day 180. These data show that the essential polyunsaturated fatty acid rich diet is able to prevent thrombosis of the biodegradable polyurethane vascular prosthesis. The combination of a synthetic material and the lipid diet experimental model, makes it possible to assess the long-term tissue-synthetic material interaction and the process of tissue growth.