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Superior Mesenteric Artery Syndrome


Superior Mesenteric Artery Syndrome (SMAS) is a rare digestive condition that causes obstruction of the 3rd portion of the duodenum due to compression by the Superior Mesenteric Artery and the Abdominal Aorta.

This leads to symptoms such as feeling full quickly, nausea and vomiting, abdominal pain, and weight loss.




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SMAS has a variety of causes, most of which relate to the SMA-aortic angle. The intestine is located in between these two arteries, and if the space between them is too small, the intestine is compressed or squished. This makes it is more difficult for food to pass through, like trying to drink out of a straw that is being crushed.

The angle can be reduced by loss of the mesenteric fat pad. The fat pad is fatty tissue that surrounds the mesenteric artery and helps to hold open the angle. Weight loss causes the fat pad to reduce and the angle to narrow. Spinal conditions, surgery, bedrest, and comorbid diseases can also cause the angle to narrow.

Check out these scans!

Two measurements are especially important for the diagnosis of SMAS:

  • The distance between the SMA and Aorta

    • Normal = 28-65 degrees

    • SMAS = 6-22 degrees

  • The angle between the SMA and Aorta

    • Normal = 10-34 mm

    • SMAS = 2-8 mm



  • Loss of fat pad

  • Weight loss

  • Congenital predisposition

  • Elongated mesentery

  • Rapid growth spurt

  • Spinal conditions


  • Feeling full quickly when eating

  • Bloating after meals

  • Burping (belching)

  • Nausea

  • Vomiting of partially digested food

  • Vomiting of bile-like liquid

  • Small bowel obstruction

  • Weight loss

  • Mid-abdominal pain


  • Diagnostics

  • CT angiogram (CTA)

  • Doppler ultrasound

  • Contrast study (UGIS)

  • Barium swallow

  • Exclusion testing




The first line of treatment is often management via high-calorie diets, positioning, and feeding tubes.

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Surgical Options

There are several surgical options for SMAS that have great success rates.


Diet & Nutrition

High-calorie diets and meal replacement shakes are ideal to regain the mesenteric fat pad.

Common Comorbidities

SMAS patients may have these conditions as well:

Find a Doctor


There are a variety of surgeries to treat SMAS. See a list of SMAS surgeons.


Find a doctor near you with our comprehensive list submitted by patients.

*Provider submissions are provided by patients and have no affiliation with the SMAS Nonprofit.


GI doctors provide diagnostic services, help with treatment, and feeding tube placement.

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You're not alone

Although SMAS is rare, the support among our community is not. Connect with other SMAS patients through support groups, mailing lists, and comfort boxes.

We also offer grants to help with medical care.

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