Screening for mesenteric vascular insufficiency and follow-up of mesenteric artery bypass procedures.

Duplex ultrasonography is the preferred noninvasive screening test for superior mesenteric artery (SMA) and celiac artery (CA) stenosis. Although postprandial increases in SMA peak systolic velocity (PSV) are known to occur, the principal duplex criteria for hemodynamically significant SMA and CA stenosis are based on fasting flow velocities. In the SMA, a PSV > or =275 cm/s predicts a > or =70% angiographic stenosis with a sensitivity of 92% and a specificity of 96%, whereas a CA PSV of > or =200 cm/sec predicts a > or =70% stenosis with a sensitivity of 87% and a specificity of 80%. Patients with appropriate symptoms of chronic visceral ischemia and a duplex scan showing high-grade stenosis of the SMA, especially when combined with CA stenosis, should have a confirmatory mesenteric angiogram. This approach will facilitate prompt intervention in these patients. If the duplex examination indicates widely patent mesenteric arteries, alternative diagnoses should be investigated. Other applications of mesenteric duplex scanning include evaluation of median arcuate ligament syndrome and postoperative surveillance of mesenteric artery revascularizations.