A 66-year-old woman with long-standing tobacco use presented with recurrent postprandial abdominal pain and food aversion for the last 18 months. An associated weight loss of 22 lb in addition to intermittent nausea, vomiting, and diarrhea was described as well. Physical examination was remarkable for a malnourished-appearing female with right carotid, epigastric, and bilateral femoral bruits. The femoral through pedal pulses were weak but palpable. Mesenteric duplex arterial ultrasonography identified 70% to 99% stenosis within the celiac and superior mesenteric arteries with abundant diffuse aortomesenteric plaque. A computed tomographic angiogram (CTA) of the abdomen confirmed the above findings and documented a meandering mesenteric artery of Moskowitz. A diagnosis of chronic mesenteric ischemia (CMI) was made.

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  Overall incidence is quite low, patients between 40 and 70 years of age, common in women.¹

  
  
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  Etiology is atherosclerosis, usually affecting mesenteric arteries at the ostia or “spill-over” disease from the abdominal aorta.

  
  
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  Most patients are smokers and hypertensive.

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  Celiac artery (CA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) usually have good pre-existent collaterals; therefore, usually two of three arteries must be critically stenosed or occluded before symptoms arise.

  
  
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  Single arterial disease may become symptomatic if there is no good collateral circulation.

  
  
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  CMI can lead to intestinal malabsorption, inanition, bowel infarction, and ultimately death.

Symptoms

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  Classic triad of abdominal pain, food fear, and weight loss.

  
  
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  Almost all patients develop central abdominal pain, the onset of which is usually 30 minutes postprandial, lasting minutes to hours. Patients learn to associate pain with food and hence develop food fear. Poor dietary intake leads to malnutrition and weight loss.

  
  
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  Ischemic ulcerations in the stomach, duodenum, or colon may cause epigastric pain, nausea, emesis, gastrointestinal bleeding, or change in bowel habits resultant of colonic strictures.

Signs

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  Patients are generally thin, underweight, with a scaphoid abdomen. Muscle wasting is seen in advanced cases.

  
  
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  However, not all patients appear emaciated as CMI can affect morbidly obese patients where a 20- to 30-lb weight loss is not readily noticeable.

  
  
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  Abdominal bruit and tenderness may be present, but peritoneal signs are typically absent.

  
  
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  Two-thirds of patients have evidence of atherosclerosis in other vascular beds (cerebrovascular, coronary, renal, and lower extremities) such as carotid bruits, coronary artery bypass or stents, and absent pedal pulses.²

Laboratory Testing

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  Nonspecific

Imaging Studies

Duplex Ultrasound Scan

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  Elevated peak systolic velocities (PSVs) of greater than 200 cm/s in the CA and greater than 275 cm/s in the SMA are indicative of greater than 70% stenosis (Figures 47-1 and 47-2).³ Elevated end diastolic velocities (EDVs) of 55 cm/s and 45 cm/s in the CA and the SMA, respectively, may also indicate greater than 50% stenosis.⁴ PSV greater than 275 cm/s in the IMA suggests greater than 70% stenosis (Figure 47-3).

  
  
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  Duplex ultrasound scan is limited by the presence of intestinal gas; therefore, patients need to fast overnight for this study.

Upper and Lower Endoscopy and CT Scan of Abdomen and Pelvis

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  Due to similar clinical presentations, comprehensive radiographic and endoscopic imaging are required to rule out intra-abdominal malignancies such as pancreatic or gastrointestinal neoplasms, or other causes of gastric outlet obstruction such as peptic ulcer disease.

Angiography

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  Advances in imaging technology rendered by CTA and magnetic resonance angiography (MRA) provide attractive diagnostic alternatives to formal mesenteric angiography.

  
  
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  CTA enables visualization and quantification of the extent of disease in the aorta and its visceral branches. Axial images can also be reconstructed to three-dimensional images (Figures 47-4A,B,C, and D and 47-5A,B).

  
  
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  Formal mesenteric angiography remains the gold standard for diagnosis of CMI, along with the possibility of therapeutic endovascular intervention. Angiographic information is crucial when considering open revascularization options.

  
  
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  Oblique or lateral projections are required for viewing the mesenteric arteries due to their ventral origin from the abdominal aorta (Figure 47-6).

  
  
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  Other clues to significant CMI are presence of prominent compensatory collateral circulation between the CA and the SMA (arc of Bühler, arc of Barkow), and the SMA and the IMA (arc of Riolan or meandering mesenteric of Moskowitz) (Figure 47-7A,B).