29 - Pathophysiology of vascular graft infections

Summary

INTRODUCTION

The introduction of prosthetic grafts has revolutionised the management of vascular disease but graft infection although uncommon, remains a dreaded complication With associated significant morbidity and mortality. Mortality occurs in approximately one third of all vascular graft infections, with mortality highest when an aortic prosthesis is involved. As many as 75% of survivors of an infected aortic prosthesis require amputation of a limb, with the incidence of amputation highest when the infection involves more distal prosthetic grafts. The incidence of graft infections is difficult to quantify as infection may manifest many years after implantation with many reports being isolated or as part of case series. Nevertheless, the reported incidence is in the order of 5%, varying according to the site of operation, being higher when a groin incision is used, or if the procedure is an emergency or a redo procedure. Infection following endovascular stent deployment has been reported although its incidence is considered to be very low.

NATURAL HISTORY OF PROSTHETIC VASCULAR GRAFT INFECTIONS

Early prosthetic vascular graft infections typically occurring in the first four months following placement are relatively uncommon (approximately 1%) and are usually caused by the more virulent micro-organisms, such as S. aureus, E. Coli, Pseudomonas, Klebsiella, Proteus and enterobacter. Late prosthetic vascular graft infections are the result of two possible mechanisms. Firstly, by haematogenous seeding from a septic focus elsewhere or by the prosthetic graft becoming infected with enteric contents following a graft-enteric erosion.