Fistula from an internal iliac artery aneurysm to the sigmoid colon after endovascular arterial repair

An 82-year-old patient presented with a history of fever for 2 weeks and occasional rectal bleeding. He had undergone endovascular repair of a left internal iliac artery aneurysm (IIAA) 3 years previously ([Fig. 1]); distal occlusion of the IIAA with coil embolization and proximal occlusion using an aorto–external iliac artery stent graft achieved successful exclusion of the IIAA ([Fig. 2]). Contrast-enhanced computed tomography showed an IIAA (diameter, 6 cm) without obvious enhancement but with massive air in the aneurysm ([Fig. 3]). Colonoscopy revealed an ulcer (diameter, 3 cm) with a base covered with feces, approximately 20 cm from the anal verge ([Fig. 4]). Gastrografin enema indicated a fistula from the sigmoid colon to the IIAA ([Fig. 5]). The patient underwent colostomy, resulting in relief of symptoms including fever and rectal bleeding, and rapid decrease in the size of the IIAA, which finally disappeared.

Fig. 1 Contrast-enhanced computed tomography showed a 5 cm in diameter internal iliac artery aneurysm prior to endovascular arterial repair.

Fig. 2 Three-dimensional computed tomography angiography after endovascular arterial repair indicated exclusion of the internal iliac artery aneurysm by coil embolization (arrow) and stent grafting (arrowhead).

Fig. 3 Contrast-enhanced computed tomography indicated the presence of abundant air in the aneurysm, which was close to the sigmoid colon. a Axial view, b coronal view.

Fig. 4 Colonoscopy revealed an ulcer with a diameter of 3 cm, the base of which was covered with feces.

Fig. 5 Gastrografin enema showed a fistula between the aneurysm (arrows) and the sigmoid colon (arrowhead).

Aneurysms of the internal iliac artery are rare, representing only 1 % of all cases of aortoiliac aneurysmal disease [1]. Rupture of an IIAA to adjacent organs, including the extremely rare complication of rupture into the rectosigmoid colon, is associated with high mortality [2] [3]; for this reason, prophylactic repair is recommended for IIAAs more than 3 cm in diameter. Traditionally, open surgery was used for IIAA repair; however, open surgery is associated with high morbidity and mortality rates. Recently, endovascular repair of IIAA, including by stent grafting, various embolization techniques, or a combination of both, is being increasingly performed in clinical practice as a novel, less invasive treatment for these aneurysms. However, the long-term complications of endovascular repair of IIAA remain unclear [4] [5]. The case reported here represents a rare, unusual complication of an IIAA–colon fistula after endovascular repair. Even if an IIAA is excluded by endovascular repair, if the patient subsequently presents with fever and/or rectal bleedings and – particularly if the aneurysm has not decreased in size since the repair – physicians should be aware that an IIAA–colon fistula may be present.

Endoscopy_UCTN_Code_CCL_1AF_2AH

Competing interests: None

• References

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