Chronic Mesenteric Ischemia

• Mesenteric artery occlusive disease (MAOD)

  • Obstruction of blood flow in one or more of the major mesenteric arteries

  • May be symptomatic

• Chronic mesenteric ischemia (CMI):

  • Clinically symptomatic hypoperfusion of the bowel as a result of MAOD

  • Hypoperfusion is typically episodic but may be constant in advanced disease [27]

Epidemiology

• MAOD is common, while CMI is rare.

• CMI most commonly occurs in adults > 60 years of age; ♀ > ♂

Etiology

• Atherosclerosis is the main cause of CMI.

• Less common causes: median arcuate ligament syndrome, vasculitis, mesenteric venous thrombosis

Pathophysiology

• Slowly progressing stenosis of two or more of the main mesenteric arteries: SMA, IMA, and/or celiac artery → postprandial mismatch between splanchnic blood flow and intestinal metabolic demand → postprandial pain

• If only one main artery is affected, collateral connections between the arteries can form and compensate for the reduced flow; these patients may be asymptomatic.

• Thrombus formation in addition to stenosis can lead to acute-on-chronic mesenteric ischemia, which leads to AMI.

CMI manifests as postprandial pain because oxygen demand increases significantly during digestion but the supply is limited by the fixed obstruction.

• Postprandial abdominal pain: begins 10–30 minutes after eating and lasts 1–2 hours

• Food aversion (sitophobia): fear of eating because of postprandial pain

• Unintended weight loss

• Nonspecific symptoms: e.g., nausea, diarrhea, bloating

• Abdominal bruit on auscultation

The recurrent dull postprandial pain associated with CMI is sometimes referred to as intestinal or abdominal angina.

Evidence of mesenteric artery stenosis is diagnostic for CMI in patients with suggestive clinical features and no other etiologies of postprandial abdominal pain. [27]

• Angiography: to confirm the diagnosis in symptomatic patients

  • Modalities

    • Duplex ultrasound of the mesenteric arteries: preferred screening test

    • CTA: preferred definitive diagnostic test

  • Findings: Mesenteric artery stenosis of > 70% is typically considered clinically relevant.

• Laboratory studies: nonspecific; may show findings suggestive of malnutrition [15]

• Malignancy (e.g., gastric cancer, pancreatic cancer)

• Chronic cholecystitis

• Chronic pancreatitis

• Inflammatory bowel disease

• Irritable bowel syndrome

• Infectious gastroenteritis

• Celiac disease

• Peptic ulcer disease

Approach

• Offer revascularization to all patients.

• Provide nutritional therapy while awaiting revascularization.

Revascularization

• Definitive therapy

• Endovascular procedures (e.g., angioplasty, stenting) are preferred.

• Surgical revascularization is typically reserved for lesions not suitable for an endovascular approach.

Revascularization is recommended in all patients with CMI.

Nutritional therapy

• Frequent, small meals and a low-fat diet may provide some symptom relief.

• Total parenteral nutrition should only be considered as a temporary supportive measure.