Visceral artery aneurysms are abnormal focal dilatations of splanchnic arteries supplying abdominal organs. Visceral artery aneurysms include both true aneurysms and pseudoaneurysms.
Owing to different clinical manifestations and a unique, specific, pathology, renal artery aneurysms are discussed separately.
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Epidemiology
The reported incidence of visceral artery aneurysms is approximately 0.01% to 2% on autopsy and angiographic studies 2, with over half the cases involving splenic artery aneurysms.
Clinical presentation
Most patients are asymptomatic and these aneurysms are usually discovered incidentally. Less frequently they are associated with abdominal pain or are palpable as a pulsatile mass in the abdomen.
Up to 25% may be complicated by rupture 3. In these cases, patients present with acute abdominal pain and bleeding that is associated with a high rate of morbidity and mortality 4.
Pathology
Etiology
Visceral artery aneurysms are usually degenerative and related to a deficiency of the arterial media with loss of elastic fibers and reduced smooth muscle. Other possible causes are atherosclerosis, fibromuscular dysplasia, collagen disorders, trauma, inflammation, infection, or vasculitis 1. Pancreatitis may promote the destruction of the arterial wall resulting in pseudoaneurysms of related visceral arteries. Segmental arterial mediolysis is also an increasingly recognized cause.
Distribution
Multiple aneurysms are present in approximately one-third of the cases 3. The distribution among visceral arteries is 1:
- splenic artery aneurysm: ~70% (range 60-80%)
- hepatic artery aneurysm: ~20%
- superior mesenteric artery aneurysm: ~5%
- gastroduodenal artery and pancreatic branches: ~6%
- celiac artery aneurysm: ~4%
- gastric and gastroepiploic artery aneurysm: ~4%
- jejunal and ileocolic arteries: ~3%
- inferior mesenteric artery aneurysm: <1%
Treatment and prognosis
Follow-up and treatment recommendations vary somewhat for different types of visceral artery aneurysms, and are discussed in more detail in their respective articles.
In general, treatment for visceral artery aneurysms is generally recommended when they are >2 cm in diameter.
Follow-up recommendations some types of visceral artery aneurysms is not established. Patients with pancreaticoduodenal aneurysms (e.g. post-Whipple procedure patients) are thought to be at higher risk of rupture than other visceral artery aneurysms. If the aneurysm is thought to be a pseudoaneurysm, it would probably be prudent to have a shorter follow-up interval.
History and etymology
Visceral is the adjectival form of 'viscera' which is the Latin term for 'internal organs' 6,8.
The term 'splanchnic' is derived from the ancient Greek word σπλαγχνον (splanchnon) meaning 'the innards' 6,7.
The word aneurysm also traces its roots back to ancient Greek, specifically the word ἀνεύρυσμα (aneurysma), literally translating as an 'aperture'. It is itself a compound construction, derived from two roots, 'ἄνω-' (ano) meaning 'up' and 'εὐρύς-' (eurys), meaning 'wide' 7,9.
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