II. Pathophysiology
- Fistula formation from aorta to adjacent bowel
- Complication of aortic repair (stenting, grafting)
- Infection of aortic graft material is cause in most cases
- Onset typically in first year after repair
III. Findings
- Gastrointestinal Bleeding (80%)
- Sepsis (44%)
- Abdominal Pain (30%)
- Back Pain (15%)
IV. Imaging: CT Aorta Angiogram
-
Intravenous Contrast only
- No Oral Contrast (obscures bleeding within bowel lumen)
- CT Aorta Angiogram with 3 phase protocol of Chest, Abdomen, Pelvis
- Noncontrast CT
- Arterial Phase CT with contrast injection
- Delayed Imaging CT at 80 sec
- Findings
- Active bleeding (e.g. into bowel lumen)
- Aortic wall discontinuity
- Focal bowel wall thickening
- Loss of fat between aorta and bowel wall
- Signs of infection
- Fat stranding
- Fluid collection (may be normal in first 3 months after surgery)
- Periaortic gas (may be normal up to 4 weeks after surgery)
- Differential diagnosis findings
- Efficacy
- Test Sensitivity: 40 to 90%
- Test Specificity: 33 to 100%
V. Management
- Broad spectrum Antibiotics
- Surgical repair including removal of infected graft material
VI. References
- Broder (2021) Crit Dec Emerg Med 35(12): 14-5
- Vu (2009) Radiographics 29: 197-209 [PubMed]