Local treatment of prosthetic vascular graft infection with multivesicular liposome-encapsulated amikacin.

BACKGROUND: Contaminated surgical fields limit the use of prosthetic vascular grafts. We studied the efficacy of sustained-release amikacin applied locally to contaminated grafts in the prevention of infectious complications. MATERIALS AND METHODS: Thirty-one New Zealand white rabbits underwent placement of a polytetrafluoroethylene (PTFE) interposition graft in a 1-cm segment of the descending aorta. The surgical field was infected with application of 10(5) to 10(8) Staphylococcus aureus organisms suspended in normal saline solution. Nineteen rabbits underwent contaminated aortic graft placement without treatment. Twelve rabbits were treated with local application of 2.5 ml of amikacin encapsulated in lipid particle-based sustained-release dosage form. Rabbits were observed for 2 weeks and then evaluated for the presence of graft infection. RESULTS: Seventy-five percent of the treated rabbits survived without evidence of graft infection or systemic sepsis versus 37% in the untreated group (P < 0.04). Cultures verified the absence of organisms in all surviving rabbits without clinical infection. CONCLUSIONS: Sustained-release lipid particle-encapsulated amikacin applied to contaminated PTFE grafts increased survival and decreased postoperative graft infections. Adjunctive use of local, delayed-release antibiotics in contaminated vascular beds may allow wider clinical use of prosthetic grafts.