Aorto-enteric fistulas: A physiopathological approach and computed tomography diagnosis

Abstract

Infection of an abdominal aortic prosthesis with an enteroprosthetic fistula is a very serious, life-threatening complication, leading sometimes to severe functional consequences, the most serious being amputation. Since the symptoms, if there are any, are often rather non-specific, diagnosis is frequently difficult and has always to be based on a whole series of justifications. Early diagnosis is essential and this fistula should be the first possibility considered in a patient with an abdominal aortic prosthesis who is presenting rectorrhagia or melaena (even if only to a slight degree), sepsis and/or abdominal pain. Although rare, the clinical existence of hypertrophic osteoarthropathy may assist diagnosis. A CT scan is the examination of choice, the criteria providing evidence of a fistula being the presence of gaseous images in a periprosthetic fluid collection, thickening and/or retraction of the intestinal walls in contact, the existence of a false aneurysm, and finally, very rarely, extravasation of contrast agent into the intestinal lumen. The differential diagnoses that may mimic a fistula need to be well known, and can include retroperitoneal fibrosis, an infectious aneurysm, inflammatory or infectious aortitis, and above all, a 'simple' prosthesis infection without fistulisation.

Aortoduodenal fistula after transperitoneal repair of an inflammatory abdominal aortic aneurysm: A case report

“…Aortoduodenal fistulas are difficult to diagnose because patients often have non-specific complaints such as general discomfort, weakness and weight loss and imaging is seldom clear [2,4]. Classical signs are gastrointestinal bleeding, a pulsatile abdominal mass and abdominal pain.…”

“…Typically, this bleeding is extensive but may be preceded by intermittent bleeding or herald bleeding. The sensitivity and specificity of computed tomography ranges from 40-90% and from 33-100%, respectively [4]. Signs include perigraft gas or fluid, soft tissue inflammation with edema, loss of continuous wrap of tissue around the graft and bowel wall thickening.…”

“…Despite the advancements in treatment of aortoduodenal fistulas and state-of-the-art intensive care, the prognosis remains poor, with an overall 30-days survival of 30-44% [4,5].…”

“…Signs include perigraft gas or fluid, soft tissue inflammation with edema, loss of continuous wrap of tissue around the graft and bowel wall thickening. Characteristics of other modalities, such as magnetic resonance imaging/ angiography (MRI/MRA), have not yet been sufficiently evaluated [4].…”

“…Treatment should consist of resection of the aortoduodenal fistula and preferably also the aortic graft. Revascularization can be undertaken in a variety of ways, including primary aortic repair, aortic replacement with a new prosthetic or venous graft or an extra-anatomical bypass (for example, axillobifemoral bypass) [4]. Each procedure is associated with significant complications including lower extremity amputations, aortic stump blow out and mortality [3,5].…”