Aortoesophageal fistula

Aortoesophageal (aorto-esophageal) fistulae are pathologic communications between the aorta and esophagus and result in life-threatening upper gastrointestinal hemorrhage. They are fatal in the absence of prompt management. 

Epidemiology

Aortoesophageal fistulas are a rare entity that accounts for approximately 10% of all aortoenteric fistulae and have an estimated frequency of less than 0.5% in patients admitted with upper gastrointestinal hemorrhage ^1-3. An incidence of 1.7% to 1.9% has been reported in the setting of thoracic endovascular aortic repair (TEVAR) ¹.

Associations

It has been commonly associated with rupture of the descending thoracic aorta and the following conditions ^1-6:

• aortic aneurysm

• aortic dissection

• foreign body

• malignancy: especially esophageal cancer

• infection: e.g. tuberculosis ¹

• radiotherapy

• postinterventional or postoperative complications

  • endovascular stent erosion

  • aortic graft infection

Diagnosis

The diagnosis of aortooesophageal fistulae is primarily based on imaging or CT angiography. Although upper gastrointestinal endoscopy may be performed to rule out other possible causes of upper gastrointestinal hemorrhage ^6,7.

Clinical presentation 

The patient usually presents as a case of emergency with massive hemorrhage and hematemesis. Clinical presentation is classically described by the Chiari triad ^2-6:

• mid-thoracic pain 

• sentinel arterial hemorrhage 

• exsanguination following a symptom-free period (seen in 80% of the patients)

Pathology

By definition, aortoesophageal fistulae are abnormal connections between the esophagus and the aorta, usually resulting in the passage of contents from the aorta to the esophagus or vice versa, i.e. blood into the esophagus, or air and esophageal contents into the aorta ¹. Mechanisms include direct erosion in the case of foreign bodies or implants and/or pressure necrosis of the aortic wall and soft tissues between the esophagus and aorta ^1,2.

Location

The most common location is the descending thoracic aorta, but aortooesophageal fistulae have been also reported for the aortic arch and ascending aorta ².

Radiographic features

CT

CT angiography in an aortoesophageal fistula may show ^3,5: 

• extravasation of contrast material

• air bubbles in the aortic wall or around the graft

• direct connection between the aorta and esophagus

• esophageal narrowing

• false aneurysm 

• mediastinal hematoma 

• stent migration

Radiology report

The radiology report should contain the following:

• diagnosis and location of the fistula with supporting features as

  • extravasation of contrast material 

  • air bubbles in the aortic wall or around the graft after TEVAR

• possible causes

  • implants (stent migration)

  • foreign bodies

  • true or false aortic aneurysms

  • aortic dissection

• additional features and complications

  • mediastinal hemorrhage

  • hematothorax

Treatment and prognosis 

Management usually includes a combination of bleeding control in the urgent phase and surgical intervention with radical debridement of the fistula and the contaminated zone as well as reconstruction of the aorta and the esophagus later as a semi-urgent intervention ¹. Initial treatment and bleeding control may be achieved with a Sengstaken-Blakemore tube (historical) or TEVAR ¹ followed by a radical surgery once the patient has satabilised appropriately ¹.

Prognosis is often poor with an estimated mortality rate of up to 60% within 6 months after symptom onset ^1,2.

History and etymology 

The first aortoesophageal fistula was described in 1818 by the French naval surgeon Joseph-Marie Dubreiul (1790-1852) ^8,10. 

Differential diagnosis

Aortoesophageal fistula needs to be differentiated from other causes of upper gastrointestinal hemorrhage.