Large-diameter inferior mesenteric artery in a case involving a ruptured common iliac artery aneurysm.

We report a case of a large-diameter inferior mesenteric artery (IMA) that was associated with an occluded superior mesenteric artery (SMA) and a celiac artery (CA) that had significant stenosis in a 79-year-old man with a ruptured right common iliac artery aneurysm. Nonenhanced computed tomography (CT) was performed at another hospital to examine his sudden abdominal pain; it showed the ruptured aneurysm, which prompted us to perform endovascular aneurysm repair (EVAR). CT angiography was performed to accurately evaluate the aneurysm and artery size; it revealed a large-diameter IMA, a highly developed meandering artery to an occluded SMA, and a CA with severe stenosis (A/Cover and B). EVAR was immediately halted because of concerns about intestinal necrosis and a potential severe type II endoleak because of the IMA. The patient was ultimately treated by open surgical repair, in which the aneurysm was replaced with a synthetic graft, and the IMA was anastomosed to the left leg of the Y-graft (C and D). Although the patient developed an intestinal obstruction that persisted for a month, he was discharged 2 months after surgery without the abdominal symptom. He gave informed consent for the publication of this report.

A large-diameter IMA is a rare and easily missed cause of vascular insufficiency that can be devastating if it is not recognized before EVAR. Asymptomatic mesenteric arterial stenosis, particularly the combination of SMA and CA stenosis or occlusion, was found in 0.5% of 980 patients who underwent aortography and 1.2% of 553 patients who underwent visceral duplex ultrasound. In patients with an abdominal aortic aneurysm and renal artery stenosis, significant stenosis or occlusion of the CA or SMA was reported in approximately 30% and in <10% of patients, respectively. In addition, occlusion of the SMA in patients with ≥50% CA stenosis was reported in approximately 3% of patients, similar to the patient in the current case.

In an emergency repair for a ruptured abdominal aortic aneurysm or iliac artery aneurysm, preoperative CT angiography should be performed to evaluate the aortic branches, especially the IMAs, to prevent intestinal ischemia caused by EVAR.