Mechanism of late prosthetic vascular graft infection.

This study was a retrospective analysis of 41 patients with late prosthetic graft infections (> 30 days after operation) from six hospitals in the south-west of England. The 41 patients had a median age of 66 years and generally accepted risk factors for infection were documented in 19 patients preoperatively. Thirteen patients had postoperative wound complications and three had early reoperation at the site of subsequent infection. The median time between index operation and symptoms of infection was 10 (range 1-224) months. Abscess (46%) was the most common presentation followed by false aneurysm (20%) and graft thrombosis (20%). All patients had reoperations (median two per patient, range one to seven). Seven (17%) patients died and 10 (24%) required a major amputation. Bacteria were isolated from retrieved grafts in 23/41 patients (high virulence 14, low virulence nine) and the most frequent organism was coagulase-negative Staphylococcus epidermidis (nine patients). In the majority of cases the aetiology of the late infections in this series was consistent with bacterial implantation at the index operation, but in four cases bacteraemia or intraperitoneal spread was more likely. Dental-type antibiotic prophylaxis would not have prevented any of the infections in this study. Aggressive treatment of recognized sources of infection in patients with vascular grafts is imperative.