Page 323 - Libro 2

19 — The Mesenteric Arteries
303
Critical Thinking Questions
1. A patient arrives for a mesenteric duplex exam and was not instructed to remain NPO, having just eaten a large breakfast. The patient lives 2 hours away, is unhappy she was not told to be NPO, and wants to get the test done. Do you proceed with the duplex exam?
2. During your mesenteric duplex scan, you can identify only one artery coming off the aorta that appears to be the SMA, as it parallels the more distal
aorta. Scanning more proximally, you identify the splenic and hepatic artery “seagull” sign, but are unable to demonstrate flow in the celiac artery by color or Doppler. Flow in the hepatic artery is toward the splenic artery.
How do you interpret these findings?
3. You are scanning a patient and find a celiac artery stenosis with PSV 􏰀
435 cm/s, EDV 􏰀 70 cm/s, and poststenotic turbulence beyond this high velocity. The SMA PSV 􏰀 325 cm/s and EDV 􏰀 50 cm/s. The SMA waveform demonstrates a “window,” and no poststenotic turbulence is identified. Do you conclude that the patient has significant celiac and SMA stenoses? Why or why not?
4. A patient in whom you found a significant stenosis of the celiac artery re- turns to the lab for follow-up scan s/p stenting of the celiac artery stenosis. On your exam, you find the celiac PSV 􏰀 220 cm/s and EDV 􏰀 55 cm/s, which are above your lab’s standard criteria for stenosis. The prestent veloci- ties were PSV 􏰀 450 cm/s and EDV 􏰀 75 cm/s. Do you conclude that there is a residual stenosis? How might you write an interpretation of this?
5. A young woman is referred to your lab for a mesenteric duplex study with a question of median arcuate ligament syndrome. Do you alter your stan- dard protocol for identifying significant mesenteric artery stenosis? Why or why not?
REFERENCES
1. Valentine RJ, Martin JD, Myers SI, et al. Asymptomatic celiac and superior mesenteric artery stenoses are more prevalent among patients with unsuspected renal artery stenoses. J Vasc Surg. 1991;14:195–199.
2. Jager KA, Fortner GS, Thiele BL, et al. Noninvasive diagnosis of intestinal angina. J Clin Ultrasound. 1984;12:588–591.
3. Jager K, Bollinger A, Valli C, et al. Measurement of mesenteric blood flow by duplex scan- ning. J Vasc Surg. 1986;3:462–469.
4. Moneta GL, Taylor DC, Helton WS, et al. Duplex ultrasound measurement of postprandial intestinal blood flow: effect of meal composition. Gastroenterology. 1988;95:1294–1301.
5. Flinn WR, Rizzo RJ, Park JS, et al. Duplex scanning for assessment of mesenteric ischemia. Surg Clin North Am. 1990;70:99–107.
6. Moneta GL, Yeager RA, Dalman R, et al. Duplex ultrasound criteria for diagnosis of splanch- nic artery stenosis or occlusion. J Vasc Surg. 1991;14:511–518; discussion 8–20.
7. Bowersox JC, Zwolak RM, Walsh DB, et al. Duplex ultrasonography in the diagnosis of ce- liac and mesenteric artery occlusive disease. J Vasc Surg. 1991;14:780–786; discussion 6–8.
8. Moneta GL, Lee RW, Yeager RA, et al. Mesenteric duplex scanning: a blinded prospective
study. J Vasc Surg. 1993;17:79–84; discussion 5–6.
9. Zwolak RM, Fillinger MF, Walsh DB, et al. Mesenteric and celiac duplex scanning: a valida-
tion study. J Vasc Surg .1998;27:1078–1087; discussion 88.
10. Kadir S. Atlas of Normal and Variant Angiographic Anatomy. Philadelphia, PA: W.B. Saunders;
1991.