Question 8

Regarding blood supply to the abdominal viscera:

a)    List the abdominal structures supplied by the coeliac axis, superior mesenteric artery (SMA) and inferior mesenteric artery (IMA).    (30% marks)

b)    Explain which areas of intestine are more susceptible to mesenteric arterial ischaemia.
(10% marks)

c)    Compare and contrast the risk factors, clinical characteristics, treatment, and prognosis of mesenteric arterial ischaemia (occlusive and non-occlusive) and mesenteric venous thrombosis.
(60% marks)

[Click here to toggle visibility of the answers]

College answer

Not available.


a) The structures supplied by each major branch are:

  • Coeliac trunk:
    • Abdominal part of the oesophagus
    • Stomach
    • Superior half of the duodenum
    • Liver
    • Superior half of the pancreas
    • Spleen
  • Superior mesenteric artery:
    • Intestine, from the lower half of the duodenum down to the splenic flexure of the large intestine
  • Inferior mesenteric artery:
    • Colon, from the splenic flexure down to the sigmoid and superior portion of the rectum

b) Areas of intestine which are more susceptible to mesenteric arterial ischaemia:

  • SMA is particularly susceptible to embolic ischaemia due to the acute angle of its take-off from the aorta and its higher blood flow rate.
  • These are watershed regions which are more susceptible to non-occlusive mesenteric ischaemia (NOMI), eg. where the cardiac output is low, or where the patient is completely full of catecholamines. These are:
    • The pancreas, a watershed between the coeliac trunk and SMA
    • The splenic flexure, a watershed between the branches of the SMA and IMA


The clinical scenario is said to differentiate the causes of mesenteric ischaemia, as the clinical findings are typically similar for all of them:

  • Abdominal pain
  • Nausea
  • Vomiting
  • Diarrhoea
  • PR bleeding
  • Peritonism

And if you wait long enough, everything starts looking like severe septic shock and multiorgan system failure. In short, the abdomen is usually the same on examination, and the way you come to the conclusion that this must be embolic or venous, is by discovering that the patient is in AF, or has recently had a bowel resection for a colonic carcinoma, or something along those lines. Because of this, the risk factors and clinical characteristics were rolled together in this tabulated response. 

Type   Risk factors and
clinical characteristics
Treatment   Prognosis
Occlusive mesenteric ischaemia

History of:

  • Angiography
  • Intra-aortic balloon pump counterpulsation
  • Cardiac surgery
  • Infective endocarditis
  • Atrial fibrillation
  • Large areas of infarcted LV or LV aneurysms (mural thrombi)
  • Infective endocarditis


  • Abrupt onset
  • Endovascular repair
  • Open repair with or without vascular bypass
  • Catheter-directed clot aspiration or  thrombolysis
  • Stenting of dissected segments
  • Good prognosis with early detection and aggressive management
  • Poor prognosis in late presentation with septic shock and MOSF
Non-occlusive mesenteric ischaemia
  • Shock states, especially those with increased SVR (eg. cardiogenic or obstructive shock)
  • High dose vasopressors, eg. noradrenaline and vasopressin
  • Insidious subacute onset
  • Management of the shock state which focuses on maximising splanchnic blood flow (eg. decreased doses of vasopressors, increased inodilators
  • Catheter-directed vasodilators may be an option (eg. papeverine)
  • Stening of stenosis
  • As poor as the underlying cause
  • Better if there is stentable stenosis of the mesenteric vessels
Venous mesenteric ischaemia
  • Generic clot risk factors
    • Factor V Leiden, prothrombin mutation, protein C or S deficiency
    • Antiphospholipid syndrome 
    • Malignancy
    • Oral contraceptives
  • Specific mesenteric venous risk factors
    • Inflammatory bowel disease
    • Abdominal surgery, especially splenectomy
    • Portal hypertension
    • Pancreatitis
    • Abdominal trauma
  • Subacute onset
  • Anticoagulation
  • Endovascular clot retrieval
  • Relatively good prognosis, even with conservative management, especially if the bowel has not infarcted


Acosta, Stefan, and Martin Björck. "Modern treatment of acute mesenteric ischaemia." British Journal of Surgery 101.1 (2014).

Schofield, Nick, et al. "Acute mesenteric ischaemia." Journal of the Intensive Care Society 15.3 (2014): 226-230.

Clair, Daniel G., and Jocelyn M. Beach. "Mesenteric ischemia." New England Journal of Medicine 374.10 (2016): 959-968. (pdf)

Pecoraro, Felice, et al. "Chronic mesenteric ischemia: critical review and guidelines for management." Annals of vascular surgery 27.1 (2013): 113-122.

Mastoraki, Aikaterini, et al. "Mesenteric ischemia: pathogenesis and challenging diagnostic and therapeutic modalities." World journal of gastrointestinal pathophysiology 7.1 (2016): 125.

Amini, Afshin, and Shivaraj Nagalli. "Bowel ischemia." StatPearls [Internet] (2020).

Bala, Miklosh, et al. "Acute mesenteric ischemia: guidelines of the World Society of Emergency Surgery." World Journal of Emergency Surgery 12.1 (2017): 1-11.

Hmoud, Bashar, Ashwani K. Singal, and Patrick S. Kamath. "Mesenteric venous thrombosis." Journal of clinical and experimental hepatology 4.3 (2014): 257-263.

Park, Woosup M., et al. "Contemporary management of acute mesenteric ischemia: factors associated with survival." Journal of vascular surgery 35.3 (2002): 445-452.

Leone, Marc, et al. "Outcome of acute mesenteric ischemia in the intensive care unit: a retrospective, multicenter study of 780 cases." Intensive care medicine 41.4 (2015): 667-676.