title: Usefulness of fasting and postprandial duplex ultrasound examinations for predicting high-grade superior mesenteric artery stenosis.
abstract: OBJECTIVE
  A fasting duplex ultrasound examination of the superior mesenteric artery (SMA) accurately detects high-grade (> 70%) stenosis. It has been postulated that postprandial mesenteric duplex scanning may further stratify stenosis and improve the ability of a fasting examination to detect a high-grade stenosis. We performed fasting and postprandial duplex scanning of 25 healthy controls and 80 patients with vascular disease undergoing aortography to determine whether postprandial mesenteric duplex scanning provides information beyond a fasting study alone.
  
  
  METHODS
  Patients with vascular disease were divided into three groups based on lateral aortography results: group 1, 0% to < 30% SMA stenosis (n = 61); group 2, 30% to < 70% stenosis (n = 10); and group 3, 70% to 99% stenosis (n = 9). Fasting mesenteric duplex scanning was defined as positive for 70% to 99% stenosis if the peak systolic velocity (PSV) was > or = 275 cm/s. The ability of either fasting or postprandial mesenteric duplex scanning, and their combination, to predict high-grade (70% to 99%) SMA stenosis was determined using angiographic control.
  
  
  RESULTS
  Mean fasting SMA PSV did not differ among controls and groups 1 and 2. Postprandial PSV increased significantly in all groups, but was not different among controls and groups 1 and 2. Mean fasting PSV was significantly higher, and the postprandial increase in PSV significantly lower, in group 3 compared with controls and with groups 1 and 2. Fasting mesenteric duplex scanning predicted 70% to 99% SMA stenosis, with 89% sensitivity, 97% specificity, 80% positive predictive value, 99% negative predictive value, and 96% accuracy. Corresponding values for postprandial scanning were 67%, 94%, 60%, 96%, 91%, and for the combination of normal fasting and postprandial scanning 67%, 100%, 100%, 96%, 96%, respectively.
  
  
  CONCLUSIONS
  Postprandial increases in SMA PSVs are blunted in patients with high-grade stenosis, but feeding velocities do not stratify between lesser degrees of stenosis. Both fasting and postprandial PSVs identify high-grade (> 70%) stenosis. Their combination marginally improves fasting duplex scan specificity and positive predictive value. Postprandial scanning is not necessary for the diagnosis of high-grade stenosis if a fasting study identifies a PSV > or = 275 cm/s. The combination of normal fasting and postprandial mesenteric duplex ultrasound scanning may effectively rule out high-grade SMA stenosis.
authors.affiliation: Department of Surgery, Oregon Health Sciences University, Portland, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Gentile
authors.forename: G L
authors.initials: GL
authors.lastname: Moneta
authors.forename: R W
authors.initials: RW
authors.lastname: Lee
authors.forename: P A
authors.initials: PA
authors.lastname: Masser
authors.forename: L M
authors.initials: LM
authors.lastname: Taylor
authors.forename: J M
authors.initials: JM
authors.lastname: Porter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001161:Arteriosclerosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D016001:Confidence Intervals; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000503:physiopathology; D004435:Eating; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging / Q000503:physiopathology; D008641:Mesenteric Vascular Occlusion / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013599:Systole; D013997:Time Factors; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*