Value of contrast-enhanced ultrasound for diagnosis and follow-up of renal artery stenosis in patients with chronic kidney disease.

OBJECTIVE

To evaluate whether contrast-enhanced ultrasound (CEUS) is an accurate, non-nephrotoxic diagnostic method and follow-up tool for use in patients with chronic kidney disease (CKD) and renal artery stenosis (RAS).

METHODS

In this prospective and monocentric study, we compared the sensitivity and specificity of CEUS for the diagnosis of RAS in CKD patients, using digital subtraction angiography (DSA) or computed tomographic angiography (CTA) as the gold standard methods. Further, the value of CEUS for distinguishing restenosis from other diseases was assessed. The ultrasound physicians conducted the examinations and served as the CEUS report readers who were blinded to the DSA or CTA results.

RESULTS

Patients with RAS (n = 60) were enrolled. Average patient age was 64.4 ± 18.0 years and median estimated glomerular filtration rate was 66.1 mL/min/1.73 m2. CEUS was used to image 94 stenotic renal arteries and DSA- or CTA-verified stenosis was present in 96 renal arteries. The kappa value for CEUS was 0.776 (P < 0.001), with an accuracy of 92.5%, a sensitivity of 94.7%, and a specificity of 84.0%. The accuracy of CEUS was the same for the diagnosis of the CKD3b-5 group as for the CKD1-3a group (100% vs. 87.5%, P = 0.148). There was no difference in CEUS accuracy for the diagnosis of Takayasu RAS compared with atherosclerotic RAS (95.8% vs. 91.7%, P = 0.795). Twenty-nine CEUS examinations were performed to follow in-stent restenosis or progression of RAS, with a median follow-up time of 5.0 months (range 1.0-20.0). Two cases of in-stent restenosis in patients suffering from deteriorating kidney function and recurrent hypertension were examined by CEUS.

CONCLUSION

CEUS examination is a credible alternative for diagnosing moderate and severe RAS in patients with CKD, and is a reliable tool for follow-up surveillance after renal artery revascularization treatment. It shouldn't be thought as a color-coded duplex ultrasonography rescue in these patients.