Visceral artery aneurysm

VAA rupture is rare but can be lethal. Splenic artery lesions, the most common form, have a particularly high rupture incidence. Because VAAs are infrequent and under-recognized, diagnosis is often delayed until hemorrhagic shock occurs.

A hallmark presentation is the sudden onset of abdominal pain followed by collapse, mimicking ruptured abdominal aortic aneurysm (AAA). Hemorrhage may initially be contained, stabilizing the patient before secondary catastrophic rupture occurs.

Commonly Involved Arteries

• Splenic artery
• Hepatic artery

Splenic artery aneurysm is strongly associated with increased blood flow states, notably pregnancy and portal hypertension.

Splenic artery aneurysm rupture in pregnancy is  rare, difficult to diagnose and has very high  mortality.

A diagnosis of ruptured splenic artery aneurysm should be considered in any pregnant patient who complains of the sudden onset of severe left upper abdominal pain, regardless of whether pain or shock is prominent at the time of evaluation.

Pathology

Definitions:

• True VAA: Involves all vessel wall layers (thinned but intact).
• Pseudoaneurysm (VAPA): Wall tear with hematoma due to trauma or iatrogenic injury.

As with any blood vessel, a given artery is usually defined as aneurysmal if there is a focal dilation of the artery that has a diameter more than 1.5 times the normal diameter of the artery.

VAAs/VAPAs are not usually clinically detected until their diameters are well beyond the diameter that is considered aneurysmal.

Normal artery diameters:

• Celiac trunk: 0.79 ± 0.06 cm
• Common hepatic artery: 0.50 ± 0.04 cm
• Proper hepatic artery: 0.45 ± 0.03 cm
• Splenic artery: 0.46 ± 0.03 cm

Aneurysm defined as: Focal dilation >1.5x normal diameter.

Relative Incidences:

• Splenic artery: 70%
• Hepatic artery: 20%
• Mesenteric arteries: 10%

Risk Factors

• Pregnancy (especially splenic artery aneurysm)
• Known VAA
• Connective tissue diseases (e.g. Marfan’s, SLE, PAN)
• Portal hypertension
• Atherosclerosis
• Liver transplantation

Clinical Features

Ruptured VAA symptoms:

• Acute, severe abdominal pain (esp. LUQ for splenic artery)
• Shoulder tip pain (diaphragmatic irritation)
• Sudden exertion as a trigger
• Collapse or syncope
• Possible initial stability with delayed catastrophic secondary rupture

A common diagnostic error is misattribution to benign conditions like musculoskeletal pain, renal colic, or biliary colic.

Note: Secondary rupture with Splenic AA

• The initial rupture – or “leak” – may be contained, (but also may not be),    within the retoperitoneal space or lesser sac.
• Pain and symptoms may settle – leading to a false sense of security – before definitive secondary rupture occurs into the peritoneal cavity that can have rapidly lethal consequences.
• The time to secondary rupture is variable – but can be up to 24 hours or longer.
• Secondary rupture – like that of cerebral aneurysm rupture can be catastrophic – i.e lethal – and so it is imperative that an early diagnosis of a splenic artery aneurysm rupture is made, before catastrophic haemorrhage occurs.

Examination Findings

• Vital signs: May be initially normal; shock may ensue later
• Abdomen: Tenderness, localized pain (LUQ or RUQ)
• Pregnancy: CTG for fetal assessment if stable

Investigations

Bloods:

• FBE (look for Hb drop)
• U&E / glucose
• Coags
• LFTs
• Crossmatch

Imaging:

• ECG (to rule out cardiac causes)
• FAST scan (helpful but not definitive)
• CT angiogram: Diagnostic test of choice
• Emergency laparotomy: Required if hemodynamic instability prevents imaging

Management

Incidental VAA:

• Elective repair if:
  • Symptomatic
  • Diameter >2 cm
  • Rapid growth (>0.5 cm/year)
  • Pregnancy or childbearing age
  • In transplant patients
  • All VAPAs

Ruptured VAA:

1. ABC and resuscitation
2. Analgesia (severe pain warrants suspicion)
3. Blood transfusion
4. Surgical intervention:
   • Open repair or ligation
   • Endovascular preferred in anatomically challenging or stable cases

Disposition

Urgent referral to:

• Radiology
• Obstetrics
• Surgery (preferably vascular)
• ICU
• Paediatrics (for advanced pregnancy)

Summary

Ruptured VAA should be suspected in any patient, particularly pregnant women, presenting with acute abdominal pain and collapse. Early recognition, imaging, and surgical consultation are essential to improve maternal and fetal outcomes.

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References

Publications

• Obara H, Kentaro M, Inoue M, Kitagawa Y. Current management strategies for visceral artery aneurysms: an overview. Surg Today. 2020 Jan;50(1):38-49. Epub 2019 Oct 16. Erratum in: Surg Today. 2020 Mar;50(3):320.
• Pitton MB, Dappa E, Jungmann F, Kloeckner R, Schotten S, Wirth GM, Mittler J, Lang H, Mildenberger P, Kreitner KF, Oberholzer K, Dueber C. Visceral artery aneurysms: Incidence, management, and outcome analysis in a tertiary care center over one decade. Eur Radiol. 2015 Jul;25(7):2004-14.

FOAMed

• Quo M. Abnormal vaginal bleeding. CCC