Efficacy of muscle flaps in the treatment of prosthetic vascular graft infections

Prosthetic vascular graft infection requires graft removal and often leads to limb loss. To determine whether vascularized muscle flaps could alter the course of graft infection, 18 mongrel dogs (18-29 kg) were randomized to one of three groups and underwent unilateral carotid artery bypass with 6-mm X 4-cm PTFE grafts. At implantation, the grafts were inoculated with Staphylococcus aureus, 2 x 10(7) organisms/wound. On Day 3, dogs with patent grafts underwent wound debridement, irrigation, and closure, and the treatment to which they had been randomized was carried out. Group A (n = 4, controls) received only dicloxacillin, 500 mg po bid, beginning on Day 4. Group B (n = 5) underwent transfer of a vascularized sternocephalicus muscle flap around the infected graft, but received no antibiotics. Group C (n = 5) underwent muscle transfer as in Group B and were given dicloxacillin as in Group A. Dogs were followed until anastomotic disruption occurred or for 60 days. Quantitative bacterial cultures were taken from sternocephalicus muscle and wound fluid at the time of debridement and at sacrifice. All dogs that received antibiotics without flaps or flaps without antibiotics (Groups A and B) experienced anastomotic disruption. Dogs that received both antibiotics and flaps (Group C) had a significantly lower incidence of hemorrhage (20%, P less than 0.05). At sacrifice, fewer bacterial colonies were cultured from muscle flaps of Group C as opposed to Group A dogs (0.05 +/- 0.02 x 10(5) vs 0.79 +/- 0.31 x 10(5), P less than 0.05). Muscle flaps with antibiotic therapy may prove to be effective treatment for infected prosthetic vascular grafts.