Are gram-negative bacteria a contraindication to selective preservation of infected prosthetic arterial grafts?

Abstract

Management of infected prosthetic arterial grafts has traditionally included total graft excision especially when gram-negative bacteria were cultured. Between 1973 and 1991 we treated 42 patients with infected prosthetic grafts (33 polytetrafluoroethylene (PTFE), 9 Dacron) by complete graft preservation when the graft was patent, the anastomoses were intact, and the patient did not have sepsis. The infection involved the anastomosis (36 cases) or the body (6 cases) of 33 peripheral grafts and the distal segment of five aortofemoral and four iliac-distal grafts. Cultures of the 42 infected grafts grew gram-positive bacteria in 33 cases and gram-negative bacteria in 22 cases. Treatment adjuncts included repeated, radical operative wound debridement and rarely (7 of 42) rotational muscle flaps. This management resulted in a 10% (4 of 42) hospital mortality rate and an amputation rate in survivors of 3% (1 of 38 threatened limbs). All four deaths were due to sepsis: gram-positive bacteria were cultured in all cases and gram-negative bacteria in two cases. Of the 38 survivors, 29 (76%) wounds healed and remained healed after average follow-up of 3 years (range, 1 to 18 years). Nine other patients required total graft excision for nonhealing wounds (7 cases) or delayed anastomotic hemorrhage (2 cases). Gram-negative bacteria were cultured in four, and gram-positive bacteria were cultured in six of these nine wounds. Four of nine (44%) graft infections that cultured Pseudomonas organisms healed without complications versus 23 of 33 (70%) wounds that cultured gram-positive bacteria, and 12 of 13 (92%) wounds that cultured gram-negative bacteria other than Pseudomonas organisms. Selected use of complete graft preservation is proposed as a safer, easier method for managing prosthetic graft infections caused by gram-positive bacteria or gram-negative bacteria with the notable exception of Pseudomonas infections. The latter infections should be treated by graft excision except when there is inadequate inflow or outflow for secondary revascularization or when graft excision is particularly hazardous and likely to result in major amputation or death.