Complex Hybrid Repair of a Secondary Aortoenteric Fistula

BACKGROUND: Secondary aortoenteric fistula is a rare, highly morbid and often difficult to diagnose, cause of gastrointestinal bleeding. It is associated with prior aortic surgery or placement of a synthetic aortic graft. Our case features staged hybrid endovascular stent-grafting, graft excision, aortoplasty using a bovine pericardial patch, extra-anatomical bypass and complex bowel repair. CASE REPORT: An 82-year-old man presented with gastrointestinal bleeding and Streptococcus Anginosus bacteraemia, with previous aorto-bi-iliac bypass surgery for left common iliac occlusive disease 15 years ago. Computed tomography angiography (CTA), gastroscopy, colonoscopy, capsule endoscopy and enteroscopy identified no bleeding source. Repeat CTA showed gas locules and stranding around the graft and the third part of the duodenum, concerning for fistulous communication. On the next day, a Zenith TX2 thoracic 28x80mm stent-graft was deployed into the infrarenal aorta. On laparotomy, a fistula was present between the Dacron graft and fourth part of the duodenum. The Dacron graft was excised, followed by aortic patching with bovine pericardium. A right-to-left femoral-femoral crossover graft was constructed. CT at one-month post-laparotomy showed no signs of perigraft endoleak and interval resolution of gas locules. He was transferred to a rehabilitation facility on the 34th post-operative day with a multidisciplinary follow-up arranged. DISCUSSION: Aortoduodenal fistula is a challenging entity to diagnose and should be suspected in patients with GI bleeding and prior aortic surgery. Endovascular repair alone is a less invasive option but with higher re-infection and late failure rates. Liberal use of appropriate imaging modalities, a judicious repair strategy, long-term follow-up and multidisciplinary approach are critical for its management.