Teaching Case

A 78-year-old female patient with a 3-week history of worsening haematemesis, recurrent chest pain, melaena and a previous history of thoracic aortic aneurysm repair.

We present the case of a patient with a thoracic endovascular aneurysm repair (TEVAR) of an atherosclerotic aneurysm of thoracic aorta 1.5 years before.
The patient presented with massive upper gastrointestinal haemorrhage which resulted in a difficult diagnosis by gastrointestinal endoscopy. Subsequent computed tomography angiography showed the aneurysm (8 cm) that formerly underwent stent-grafting (TEVAR), spanning the distal ascending arch and proximal descending aorta, with a mural thrombus and air bubbles inside. A huge gastric blood clot was present, which strongly suggested an aortoesophageal fistula. The CT also revealed a considerable previously undiagnosed type I-A endoleak (patient lost to follow-up). The patient underwent TEVAR revision solving the endoleak, but died of sepsis.

Aortoenteric fistulas may be primary or secondary. Primary aortoenteric fistulas are rare and almost always associated with a preexisting aortic aneurysm. Secondary aortoenteric fistulas are far more common than primary ones but nevertheless are relatively rare [1] and occur as complications of aortic reconstructive surgery with or without the placement of an aortic stent-graft.
Aortoesophageal fistula, where an abnormal communication between the oesophagus and the aorta is found, constitutes less than 10% of all aortoenteric fistulas and is a life-threatening cause of gastrointestinal bleeding [1, 2]. In this setting, secondary aortoesophageal fistula is a rare but well-recognized complication of aorta prostheses (TEVAR), that occurs relatively early after the procedure and is almost invariably fatal [3]. Other pathogenic conditions such as foreign body ingestion, oesophageal malignancy or other postoperative complications are also rare reported causes [1].
The diagnosis is often difficult. Classic patients present with the triad of midthoracic pain, sentinel arterial haemorrhage, and exsanguination after a symptom-free interval (Chiari's triad). The identification of massive upper gastrointestinal haemorrhage that is bright red and arterial in nature is characteristic. [1]
Computed tomography has become the first-line modality for imaging evaluation of suspected aortoenteric fistula, owing to its widespread availability. [1, 3].
The goal of EVAR is to achieve complete sealing of the aneurysmal sac from blood flow, to achieve general pressure relief, to avoid aneurysm expansion or rupture, and to shrink the aneurysmal sac. In the setting of an endoleak, perigraft flow in the aneurysmal sac persists, causing enlargement and rupture of the aneurysm [4]. Multiphasic contrast-enhanced CT can promptly demonstrate endoleaks, which have been classified in five types. Type I endoleak is leakage of blood between stent graft and proximal (type I-A) or distal (type I-B) EVAR landing zones, often a consequence of lack of good apposition to the aortic wall. Type II endoleak is reflux of blood through collateral vessels leading to retrograde filling of the aneurysm. Type III endoleak is leakage of blood through defect in stent-graft mesh. Type IV endoleak is associated with graft porosity, often causing self-limited leakage of blood through the substance of stent-graft. With type V endoleak, also called endotension, no definable origin can be determined. The development of an endoleak is an uncommon potential complication of EVAR and is the cause of progressive enlargement of the aneurysm and potential complications, such as aortoenteric fistulas.