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Vascular/Cardiac » Visceral vascular
Superior mesenteric artery stenosis
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Presentation An elderly man presented for abdominal ultrasound for the evaluation of mesenteric ischemia. He had symptoms of chronic abdominal pain, especially after food intake.
 
 
 
Caption: Sagittal image of a vessel at its origin
Description: This is the sagittal image of the origin of the superior mesenteric artery from the aorta. The SMA appears to completely fill with color. There is no abnormal angulation of the vessel origin.
 
 
 
Caption: Spectral analysis of the SMA at its take-off
Description: The SMA at its origin demonstrates an elevated peak systolic velocity of greater than 200 cm/sec.
 
 
 
Caption: Spectral waveform of SMA, 1-2 cm from origin
Description: The SMA at a distance of 1-2 cm from the aorta still demonstrates elevated systolic velocities.
 
 
 
Caption: Spectral waveform of the mid SMA region
Description: Persistently elevated velocities in the mid SMA region reaching up to almost 250 cm/sec are noted.
 
 
 
Caption: Spectral waveform analysis of the distal SMA
Description: The distal SMA demonstrates a normal arterial waveform with the peak systolic velocity seen returning to baseline.
 
Differential Diagnosis Superior mesenteric artery stenosis
 
Final Diagnosis Superior mesenteric artery stenosis
 
Discussion Duplex Doppler ultrasound is the preferred non-invasive modality to reliably diagnose superior mesenteric artery stenosis. This disease occurs more common in elderly patients, in whom atherosclerosis causes stenosis of the proximal SMA. Higher grade stenosis is much more reliably diagnosed by the Doppler parameters.

The patients may be asymptomatic or may have chronic intestinal ischemia and present with non-specific symptoms of post-prandial abdominal pain and weight loss.

Amongst the different Doppler criteria that have been proposed by various studies in literature, measurement of the fasting peak systolic velocity appears to be the most reliable indicator. Moneta, et al proposed a SMA peak systolic velocity of 275 cm/sec or greater and/or no color flow in the SMA as an indicator of > 70 percent vessel stenosis. The end-diastolic velocities are also elevated in high grade stenosis and a recording of 45 cm/sec or greater is suggestive of high degree stenosis [Bowersox, et al].

In cases of borderline increases in the fasting rate peak systolic velocity of SMA, a postprandial Doppler study may help in arriving at a diagnosis. Failure to demonstrate an increase in post-prandial peak systolic velocity likely suggests a hemo-dynamically significant stenosis.

An acutely angled SMA may result in a false positive diagnosis of SMA stenosis and should be kept in mind.
 
Case References 1. Moneta GL. Screening for mesenteric vascular insufficiency and follow-up of mesenteric artery bypass procedures. Semin Vasc Surg. 2001 Sep; 14(3):186-92.
2. Perko MJ. Dduplex ultrasound for assessment of superior mesenteric artery blood flow. Eur J Vasc Endovasc Surg. 2001 Feb; 21(2):106-17.
3. Lim HK, Lee WJ, Kim SH, et al. Splanchnic arterial stenosis or occlusion: diagnosis at Doppler US. Radiology. 1999 May; 211(2):405-10.
4. Gentile AT, Moneta GK, et al. Usefulness of fasting and postprandial duplex ultrasound examinations for predicting high-grade superior mesenteric artery stenosis. Am J Surg. 1995 May; 169(5):476-9.
5. Bowersox JC, Zwolak RM, Walsh DB, et al. Duplex ultrasonography in the diagnosis of celiac and mesenteric artery occlusive disease. J Vasc Surg. 1991 Dec; 14(6):780-6; Discussion 786-8.
 
Follow Up Based on the Doppler findings, this patient underwent an angiogram and the diagnosis was confirmed. An angioplasty with stent placement in the SMA was performed to relieve him of his symptoms.
 
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