Presentation and Management of a Rare and Fatal Disease: Saccular Superior Mesenteric Artery Aneurysms

Superior mesenteric artery (SMA) aneurysm (SMAA) is a fatal degeneration of the visceral arteries. Although a rarely encountered entity, it requires timely management because of the high mortality rate associated with rupture, particularly when the aneurysm is saccular in nature. As such, urgent treatment is generally indicated. We present five cases of SMAA that were managed operatively. Medical records and imaging studies from a single academic medical center from January 2016 to January 2019 were retrospectively reviewed. We describe the presentation, operative management, postoperative outcomes, and follow-up from a series of five patients with SMAA. Five patients (80% female) with true SMAA were identified and diagnosed by computed tomography angiography. All cases involved saccular aneurysms. Three presented emergently with severe abdominal pain, one of whom was to have ruptured SMAA. Two elective cases were incidentally identified on imaging. Two cases were mycotic in etiology, secondary to intravenous drug abuse and infective endocarditis. The remainder were cryptogenic. There were no patients with history of atherosclerosis or elastin/collagen disorders. All of the SMAAs involved branches or branch points of the SMA. The largest SMAA was 3.2 cm in a proximal SMA branch point. All cases were treated with open surgical resection of the SMAA (Fig, A and B). Interposition reversed saphenous vein graft was used for reconstruction in a single case involving the main SMA trunk. None of the cases required bowel resection for ischemia. The operative mortality was 20% and related to ruptured SMAA. SMAAs are particularly prone to rupture, at which point intraoperative mortality can reach up to 30%. Accordingly, many authors suggest repair of SMAAs even in asymptomatic patients. Earlier studies supported revascularization, but this has more recently shifted to ligation alone because of the dense collateralization network. In addition, bowel should be closely examined for ischemic changes whenever the integrity is in question. The presenting and management features in our case series are supportive of this literature, with the exception that our population of patients was predominantly female. Future studies will continue to determine factors associated with rupture and poor outcomes along with the optimizing surgical approach.