Duplex Ultrasound in Evaluating Transplanted Renal Artery In-Stent Restenosis

To evaluate the diagnosis performance of duplex ultrasound (DUS) in predicting transplanted renal artery (TRA) in-stent restenosis (ISR).

In this retrospective study, 112 consecutive patients underwent stenting due to TRA stenosis. DUS were performed within 1 week after stenting for baseline value, and after ≥3 months follow-up for surveillance of ISR. The DUS measurements included peak systolic velocity (PSV) and PSV ratio of renal artery stent to iliac artery (RIR). Receiver operating characteristic (ROC) curves were applied to evaluate the diagnosis performance of DUS parameters in predicting ISR.

There were 69 patients (28 men; age, 38.3 ± 15.1 years) who obtained 92 adequate paired DUS and CTA after stenting, which were classified as ISR group (26 TRAs) and non-ISR group (66 TRAs). There was no difference between the two groups for baseline DUS features, including PSV_B and RIR_B. The late DUS features including stent PSV_L (475.5 vs 261.9 cm/s), RIR_L (4.10 vs 2.18), and stent PSV_L/PSV_B (2.72 vs 1.14) were significantly higher in the ISR group than the non-ISR group (all P < .0001). Stent PSV_L, RIR_L, and PSV_L/PSV_B demonstrated comparable AUCs in predicting ISR. However, the sensitivity and specificity of PSV_L/PSV_B in predicting ISR were 92.3 and 93.5%, respectively, demonstrating higher specificity with equivalent sensitivity than PSV_L and higher sensitivity with equivalent specificity than RIR_L.

DUS is an accurate technique to identify TRA-ISR. We suggest all patients should undergo DUS immediately after stenting to establish baseline value and aid in evaluating ISR at late follow-up.