ABSTRACT
Splanchnic artery aneurysms involve the celiac, superior mesenteric, and inferior mesenteric arteries and their branches. They occur relatively infrequently when compared to aneurysms of the aorta and iliac vessels, partly because there is a lower overall incidence of atherosclerosis in the splanchnic circulation. Atherosclerosis, responsible for the great majority of aortic and iliac aneurysms, is thought to be responsible for less than half of splanchnic artery aneurysms. While atherosclerosis can be found in the majority of splanchnic artery aneurysms, it is thought to be a secondary process.[1] Splanchnic artery aneurysms have a diverse etiology and a correspondingly diverse natural history. Inflammation is an important primary cause of splanchnic artery aneurysms. It may occur from a primary vasculitis such as polyarteritis nodosum, a metastatic infection such as emboli from endocarditis, or an extravascular process such as pancreatitis or a penetrating peptic ulcer. Peripancreatic pseudoaneurysms are estimated to occur in 10% of patients with chronic pancreatitis.[2] Polyarteritis nodosa is an autoimmune vasculitis which causes multiple aneurysms, typically less than 1 cm in diameter, of the small and mediumsized muscular arteries of the abdominal viscera and kidneys. Due to their small size, intraparenchymal location, and natural history, these aneurysms rupture only occasionally and do not often require surgery. In contrast, embolomycotic aneurysms have a very unpredictable natural history, which often ends in fatal rupture and, unless completely resolved on follow-up angiography, are best treated with surgery. Other important causes of splanchnic artery aneurysms include hemodynamic and connective tissue alterations as well as trauma.
