A pilot study of a triple antimicrobial-bonded Dacron graft for the prevention of aortic graft infection

ObjectivePerioperative infection of an aortic graft is one of the most devastating complications of vascular surgery, with a mortality rate of 10% to 30%. The rate of amputation of the lower limbs is generally >25%, depending on the graft material, the location of the graft and infection, and the bacterial virulence. In vitro studies suggest that an antibiotic-impregnated graft may help prevent perioperative graft infection. In a pilot animal study, we tested a locally developed technique of bonding Dacron aortic grafts with three antimicrobial agents to evaluate the ensuing synergistic preventive effect on direct perioperative bacterial contamination.MethodsWe surgically implanted a 6-mm vascular knitted Dacron graft in the infrarenal abdominal aorta of six Sinclair miniature pigs. Two pigs received unbonded, uninoculated grafts; two received unbonded, inoculated grafts; and two received inoculated grafts that were bonded with chlorhexidine, rifampin, and minocycline. Before implantation, the two bonded grafts and the two unbonded grafts were immersed for 15 minutes in a 2-mL bacterial solution containing 1 to 2 × 107 colony-forming units (CFU)/mL of Staphylococcus aureus (ATCC 29213). Two weeks after graft implantation, the pigs were euthanized, and the grafts were surgically excised for clinical, microbiologic, and histopathologic study.ResultsThe two bonded grafts treated with S aureus showed no bacterial growth upon explant, whereas the two unbonded grafts treated with S aureus had high bacterial counts (6.25 × 106 and 1.38 × 107 CFU/graft). The two control grafts (unbonded and untreated) showed bacterial growth (1.8 × 103 and 7.27 × 103 CFU/graft) that presumably reflected direct, accidental perioperative bacterial contamination; S cohnii ssp urealyticus and S chromogenes, but not S aureus, were isolated. The histopathologic and clinical data confirmed the microbiologic findings. Only pigs that received unbonded grafts showed histopathologic evidence of a perigraft abscess.ConclusionsOur results suggest that bonding aortic grafts with this triple antimicrobial combination is a promising method of reducing graft infection resulting from direct postoperative bacterial contamination for at least 2 weeks. Further studies are needed to explore the ability of this novel graft to combat one of the most feared complications in vascular surgery.Clinical RelevanceThis study introduces a novel bonded Dacron aortic graft for the prevention of perioperative aortic graft infection. The quantitative results of our experimental studies showed that the bonding of three antimicrobial agents (rifampin, minocycline, and chlorhexidine) to aortic grafts nearly prevented aortic graft infection by synergistically prolonging antistaphylococcal activity. Use of an antibiotic-bonded prosthetic graft with antistaphylococcal activity should be considered in patients who have arterial infections caused by Staphylococcus aureus. After the preventive effect of this graft and its safety have been further assessed, its use may be recommended for the in situ replacement of infected grafts and possibly for routine primary cases, especially in immunocompromised patients, patients with hostile abdomen, and patients undergoing redo procedures