Epidemiology

Risk Factors

• xxxx

---

Etiology

Primary Aortoenteric Fistula

• Definition: arises de novo between the aorta and bowel
• Epidemiology: less common than secondary aortoenteric fistula
• Physiology
  • May Involve Septic Aortitis with Formation of Aneurysm or False Aneurysm Which Erodes into Adjacent Structures
  • Commonly Isolated Organism Include Salmonella and Staphylococcus (J Vasc Surg, 1989) [MEDLINE]
• Locations
  • Duodenum (Aortoduodenal Fistula): duodenum accounts >75% of primary aortoenteric fistulas
    • Most are Located in the 3rd-4th Portion of Duodenum, Where the Duodenum is Most Closely Located to the Aorta (Surgery, 1977) [MEDLINE]
  • Stomach (Aortogastric Fistula)
  • Jejunum (Aortojejunal Fistula)
  • Ileum (Aortoilial Fistula
  • Sigmoid Colon (Aortosigmoid Fistula)

Secondary Aortoenteric Fistula

• Definition: arises between aorta and bowel following an aortic reconstruction procedure
• Epidemiology: more common than primary aortoenteric fistula
• Physiology: unclear, but may involve pulsating motion of the graft against the bowel wall, adhesion of an infected inflamed graft to the bowel, etc
• Prior Procedures
  • Surgically-Placed Aortic Graft: most common
  • Aortic Stent Graft
  • Bare Metal Aortic Stent
  • Infrarenal Aortic Ligation: importantly without any prosthetic material
• Locations
  • Duodenum (Aortoduodenal Fistula): accounts for most secondary aortoenteric fistulas
  • Colon: less common site of involvement

---

Diagnosis

Abdominal/Pelvic CT (see Abdominal-Pelvic Computed Tomography)

• Technique
  • *Abdominal/Pelvic CT with Intravenous Contrast:
  • Abdominal/Pelvic CT Angiogram:
• Findings: either the fistula itself or gas/liquid surrounding the aortic graft

Esophagogastroduodenoscopy (EGD) (see Esophagogastroduodenoscopy, [[Esophagogastroduodenoscopy]])

• Sensitivity: only 50%

---

Clinical Manifestations

Aortoenteric Fistula with Gastrointestinal Hemorrhage

• General Comments
  • Classic Triad: palpable abdominal mass + abdominal pain + gastrointestinal hemorrhage
    • Classic Triad Occurs in Only 6-12% of Cases
• Abdominal Mass (see Abdominal Mass)
• Abdominal Pain (see Abdominal Pain)
• Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage)
  • Degree of Hemorrhage Ranges from “Herald Bleed” to Exsanguinating Hemorrhage
  • Gastrointestinal Hemorrhage is the Most Common Presentation of Aortoenteric Fistula
    • Rapid Exsanguination is More Common in Secondary Aortoenteric Fistula
    • Anastomotic Fistulas More Commonly Present with Acute Gastrointestinal Hemorrhage, While Prosthetic Fistulas Often Did Not Present with Gastrointestinal Hemorrhage or Presented with Chronic Gastrointestinal Hemorrhage (Ann Surg, 1985) [MEDLINE]

Aortoenteric Fistula with Other Manifestations

• Aortic Graft Thrombosis (see Abdominal Aortic Aneurysm)
  • Epidemiology: xxxx
• Fever (see Fever)
• Malaise (see Malaise)
• Sepsis (see Sepsis)
• Weight Loss (see Weight Loss)

---

Treatment

• xxx

---

References

• Paraprosthetic-enteric fistula. Surgery. 1977 May;81(5):556-66 [MEDLINE]
• Mycotic aortic pseudoaneurysm with aortoenteric fistula caused by Arizona hinshawii. Surgery. 1982 Feb;91(2):173-7
• Gastrointestinal tract involvement by prosthetic graft infection. The significance of gastrointestinal hemorrhage. Ann Surg. 1985 Sep;202(3):342-8 [MEDLINE]
• Tuberculous aortitis presenting with an aortoduodenal fistula: a case report. Angiology. 1986 Jul;37(7):519-23
• Primary aortoduodenal fistula caused by Salmonella aortitis. J Vasc Surg. 1987 Oct;6(4):415-8 [MEDLINE]
• A ten-year experience with bacterial aortitis. J Vasc Surg. 1989 Oct;10(4):439-49 [MEDLINE]
• Aortoenteric fistula: present-day management.  Int Surg.  2011;96:266–273 [MEDLINE]
• Diverse presentation of secondary aortoenteric fistulae.  Case Rep Med.  2011;2011:406730.  Epub Dec 29 [MEDLINE]
• Clinical problem-solving. The search is on. N Engl J Med. 2013;368:562–567 [MEDLINE]