Current technology for the treatment of infection following abdominal aortic aneurysm (AAA) fixation by endovascular repair (EVAR)

In recent years, in parallel with the increase of endovascular aortic repair (EVAR) procedures performances, a rise of late open surgical removal of EVAR implants has been observed, due to non-endovascularly correctable graft complications. Among them endograft infection is a rare but devastating occurrence, accounting for an incidence ranging from 0.2% to 0.7% in major series, and almost 1% of all causes of endograft explantations. However, a real estimation of the incidence of the problem respect to the number of EVAR implantations is difficult to obtain. Time to infection is usually defined as the period between EVAR and presentation of symptoms that leads to the infection diagnosis. It can be extremely variable, depending on bacterial virulence and host conditions. The diagnosis of an endograft infection is usually based on a combination of clinical symptoms, imaging studies and microbial cultures whenever possible. If computed tomography (CT) scan is employed in almost 100% of infection diagnosis, a combination of fluorodeoxyglucose-positron emission tomography (FDG-PET) and CT scan is nowadays used with increasing frequency in order to rise the likelihood of detecting a graft infection, since even cultures of blood or samples collected from the infected field can sometimes be negative. Complete graft excision seems the best approach whenever a surgical reconstruction could be attempted. In situ reconstruction can be performed by the interposition of an autologous vein, a cryopreserved allograft or a rifampin-soaked Dacron graft. The so-called conventional treatment contemplates the re-establishment of vascularization through extranatomical routes, thus preserving the new graft material from possible contamination by the surgical field just cleaned. When severe comorbid conditions did not allow graft excision, a conservative treatment should be taken into account. It is mainly based on broad-spectrum or culture-specific antibiotic therapy combined, whenever possible, with percutaneous drainage of the infectious cavity or aneurismal sac followed by irrigation with saline and antibiotic solutions. New techniques of percutaneous drainage under CT scan guidance can allow expedite collection of fluid material for microbial culture or fluid drainage, catheter positioning to collect infectious material from the cavity and perform irrigation of the infected field or injection of iodine contrast when the suspicion of aortoenteric fistula exists.