Bacteremic infectability of vascular grafts: the influence of pseudointimal integrity and duration of graft function

This report describes an experimental study in which dogs with prosthetic graft replacement of the infrarenal abdominal aorta were challenged at progressive time intervals following graft placement with a single intravenous infusion of Staphylococcus aureus in order to determine the duration of susceptibility to graft infection of bacteremic origin. The results demonstrate that the susceptibility of a prosthetic graft to infection by bacteremic seeding virtually was 100 percent up to 1 month following graft placement. The incidence of infection then began to progressively drop but never was eliminated as demonstrated by a 30 percent incidence of graft infection in dogs so challenged 1 year graft placement. Careful scrutiny of the intimal surface of the harvested grafts, 3 weeks following bacteremic challenge, revealed that all grafts in which the pseudointimal coverage was complete were insulated effectively from infection by bacteremic seeding in that their cultures were negative. All grafts that had positive cultures for Staphylococcus aureus were noted to have either an incomplete or absent pseudointimal lining.