Late Prosthetic Vascular Graft Infections after Reconstructions on Aortoiliac Segment: An Eleven Years Experience

The purpose of the study was to evaluate the frequency and etiology of late prosthetic vascular graft infections after reconstructions on aortoiliac segment. From 2001 to 2011,545 primary reconstructions were performed on 545 consecutive patients. We had 18 cases of late intracavitary graft infections in 14 of them. A total of 58 clinical specimens collected from patients before, during and after reoperation were analyzed. Pathogens were isolated using conventional methods for aerobic and anaerobic bacteria. The isolates were identified down to species level by conventional biochemical methods, VITEK 2 and mini API Systems (bioMereux, France). During an 11-year period after prosthetic grafting of the abdominal aorta and aortoiliac segment the incidence of late (more than 4 months after implantation) infection was 3.11%. The mean interval between the initial operation and development of infection was 39.2 months (range 4 to 84). Positive microbial cultures were found in 46 clinical specimens. A total of 66 microbial isolates were cultured, comprising 27 clinical strains. Gram-positive bacteria were predominant - 15 (55.55%) strains, followed by Gram-negative bacteria - 9 (3 3.33%), Candida albicans - 2 (7.4%) and Bacteroides fragilis - 1 (3.7%). In 7 cases, the infection was monobacterial, caused predominantly by Staphylococcus species. In the rest of the cases, the infections were polymicrobial, caused by association between two microbial species. Mortality rate was 35.71% (5 cases) - in 4 of them the infection was caused by association between two species of Gram-negative bacteria or between Gram-negative bacteria and Candida albicans. The incidence of late intracavitary vascular graft infection was low. The average period for development of this complication was about 3 years after reconstruction. Among the causative agents, Gram-positive microorganisms had a predominant role but infections caused by Gram-negative bacteria, especially when they were in association, had a worse outcome.