Michael Azzopardi¹, Tom Wallace², Yazan S. Khaled^1,3

¹Leeds Institute of Medical Research, Department of Academic Surgery, St James’s University Hospital, Leeds, United Kingdom

²Leeds Vascular Institute, Department of Vascular Surgery, Leeds General Infirmary, Leeds, United Kingdom

³School of Medicine, University of Leeds, United Kingdom

“Written informed consent was obtained from the patient to publish this report in accordance with the journal’s patient consent policy”.

Corresponding author:

Mr. Yazan S. Khaled

Leeds Institute of Medical Research & School of Medicine

University of Leeds

Clinical Sciences Building

St James’s University Hospital

Leeds, LS9 7TF

United Kingdom

Phone: +44 113 2065281

Fax: +44 113 2065281

Email: Y.Khaled@leeds.ac.uk

Keywords:

Artery-enteric fistula, gastrointestinal haemorrhage, sigmoid cancer, graft explant.

Conflict of interest: The authors declare no conflict of interest.

This case study discusses the staged management of a 78-year old patient presenting with life-threatening lower gastrointestinal (GI) bleeding secondary to an aortoiliac graft-enteric fistula (GEF) into the sigmoid colon on the background of an adenocarcinoma and diverticular disease. The patient had an aorto bi-iliac synthetic dacron graft repair of an abdominal aortic aneurysmal (AAA) some 20 years prior. Here, we present a case of successful endovascular treatment of massive haemorrhage, as a bridge to definitive second-stage dacron graft explant and autologous vein reconstruction with a simultaneous anterior resection.

Arterio-enteric fistula (ArEF) is an umbrella term that encompasses various fistulations between the great arteries and the gastrointestinal (GI) tract, including aortoesophageal, aortogastric, aorto-enteric fistulas (AEF) and iliac artery-enteric fistula (IEF).

ArEF is a rare cause of potentially lethal GI bleeding and the vast majority appear to occur in the aorta, with few examples of IEF encountered in modern literature. These fistulas can occur via two separate pathological mechanisms. Primary ArEF are rare, occurring as a spontaneous communication between an artery and bowel from a combination of direct frictional forces and inflammatory processes [1]. The most encountered mechanism contributing to primary ArEF is aneurysmal formation, which is theorised to develop into a fistula from the repetitive mechanical forces exacerbated by cardiac pulsations and peristaltic movements [2]. This gradual degradation and erosion of the outermost layers of bowel and artery can also result spontaneously in other pathological circumstances; including tumours, diverticular disease, sepsis, syphilis and tuberculosis [3-6].

Secondary ArEFs are much more common given that they are an iatrogenic complication of open or endovascular AAA repair using synthetic graft. In this case, seeding of bacteria onto the synthetic graft is known to exacerbate the erosive mechanisms involved in fistula formation [2]. Hallet et al . have suggested a 1.6% chance of fistula formation after AAA graft repair [7]. The vast majority of ArEFs encountered in literature are between the abdominal aorta and duodenum due to their intimate anatomical association. IEFs are rarely encountered, but it appears that the majority occur secondary to pelvic surgery, malignancy, radiotherapy and infection [8].

In this case report we encountered a 78-year old patient, 20 years after an elective AAA Y-graft repair, presenting to emergency with haematochezia as a result of a fistula between the right common iliac artery (CIA) and sigmoid colon. The patient was known to have a sigmoid adenocarcinoma and diverticular disease from a colonoscopy three weeks prior to his emergency presentation. The rarity and complexity of this case necessitated a multidisciplinary staged approach to the management, both in the acute and elective setting, leading to a favourable outcome.