Duplex ultrasonography in assessing restenosis of renal artery stents.
OBJECTIVE
To determine the accuracy and optimal threshold values of duplex ultrasonography (US) in assessing restenosis of renal artery stents.


METHODS
Twenty-four consecutive patients with 33 renal arteries that had previously been treated with placement of a Palmaz stent underwent duplex US prior to intraarterial digital subtraction angiography (DSA), which was the reference standard. Diagnostic accuracy of in-stent peak systolic velocity (PSV) and reno-aortic ratio (RAR = PSV renal stent/PSV aorta) in detecting > 50% in-stent restenosis were evaluated by the receiver operating characteristic curve. Sensitivity and specificity were determined using the optimal threshold values, and using published threshold values: RAR > 3.5 and in-stent PSV > 180 cm/sec.


RESULTS
Six examinations were technically inadequate. Nine stents had residual or restenosis > 50% at DSA. The two duplex parameters were equally accurate since areas under the curves were similar (0.943). With optimal threshold values of 226 cm/sec for PSV and 2.7 for RAR, sensitivities and specificities were 100% and 90%, and 100% and 84%, respectively. Using the published duplex criteria resulted in sensitivities and specificities of 100% and 74% for PSV, and 50% and 89% for RAR.


CONCLUSIONS
Duplex US is a sensitive modality for detecting in-stent restenosis if laboratory-specific threshold values are used.
Bakker
J
J
Department of Radiology, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Beutler
J J
JJ
Elgersma
O E
OE
de Lange
E E
EE
de Kort
G A
GA
Beek
F J
FJ
D000368:Aged; D015901:Angiography, Digital Subtraction; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012372:ROC Curve; D012008:Recurrence; D012077:Renal Artery / Q000000981:diagnostic imaging; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000628:therapy*; D012680:Sensitivity and Specificity; D015607:Stents; D018616:Ultrasonography, Doppler, Duplex