Infections of the aorta

Abstract

Infection of the aorta continues to be a clinical challenge with high morbidity and mortality. The incidence varies between 0.6 and 2.6%. There has been a steady increase in graft infections, especially endograft infections, due to increased procedures (0.2 to 5%). Staphylococcus species remains the most common organism; however, gram-negative and rare causative agents are also reported. The clinical presentation can be very diverse and a high degree of suspicion is necessary to diagnose them. Sometimes, they may present as an emergency with rupture or fistulation. Diagnosis is based on a triad of clinical features, microbial cultures and imaging. Culture-specific antibiotics are mandatory during the entire course, but seldom cure alone. Surgical management remains the standard of care and involves an integrated approach involving debridement, reconstruction and use of adjuncts. Various aortic substitutes have been described with advantages and limitations. Pericardial tube grafts have emerged as a good option. Endo-vascular options are practiced mostly as a bridge to definitive surgery. A small role for conservative management is described. Aortic fistulation to the gut and airway carries a very high mortality. There are no large series in the literature to define guideline-directed treatment and most often it is a customized solution. The 30-day mortality remains close to 30%. Outcomes depend on multiple factors including patient's age, the timing of presentation, diagnosis, causative organism, host status and the treatment strategy adopted.

Keywords: Aortic graft infections; Aortic infections; Graft conservation; Omentopexy; Pericardial tube; Stent graft infections.

Fig. 1

Aetiology, causative agents and common location of different infections of the aorta (adapted from [4, 5])

Fig. 2

Donut chart depicting the relative frequency of the pathogens causing the aortic graft infections (adapted from [22])

Fig. 3

Venn diagram showing the triad of clinical features, laboratory investigations and imaging (ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; CT, computed tomography; MRI, magnetic resonance imaging; WBC, white blood cell; FDG-PET, fluoro-deoxy-glucose-positron emission tomography)

Fig. 4

a 3D reconstruction of a CT angiography which depicts a mycotic pseudoaneurysm (green arrow) in a patient 1 year after TEVAR for an infrarenal aortic aneurysm. b, c Contrast CT angiography images showing peri-graft air (red arrow) which is suggestive of an aortic infection ± aorto-enteric fistula (3D, 3-dimensional; CT, computed tomography; TEVAR, thoracic endo-vascular aortic repair)

Fig. 5

Management of Aortic Graft Infection Collaboration (MAGIC) criteria for the diagnosis of Aortic Graft Infections (adapted from [41]) (AEF, aorto-enteric fistula; ABF, aorto-bronchial fistula; CTA, CT angiography; AGI, aortic graft infections; C, centigrade; FDG-PET, fluorodeoxyglucose-positron emission tomography; WBC, white blood cell; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein)

Fig. 6

The principles of management of aortic infections

Fig. 7

Intra-operative picture showing the reconstructed infra-renal aorta with a xeno-pericardial tube graft (courtesy of Dr.V.V. Bashi and Dr. A. Mohammed Idhrees)

Fig. 8

Options for aortic graft infections with respective pros and cons (adapted from [22])

Fig. 9

a, b Intra-operative image of an extensive infection involving the ascending aorta prosthetic graft which was managed with graft conservation and omentopexy (courtesy of Dr. V.V. Bashi and Dr. A. Mohammed Idhrees)

Fig. 10

Management algorithm—aortic infections