Controversy exists in the management of renal artery stenosis (RAS) after recent trials have shown conflicting results with regard to angioplasty. A recent article by Boateng et al in the American Journal of Kidney Diseases discusses the prevalence, risk factors, and treatment of in-stent stenosis in the setting of RAS. The following questions will test your knowledge on RAS.

1. The definition of renal artery in-stent stenosis varies in published reports. Which of the following definitions is used by the American Heart Association?

A. Renal artery narrowing >50% of the maximal luminal diameter

B. Renal artery narrowing of 50% plus a systolic pressure gradient across the stenosis of at least 20 mmHg

C. Renal artery narrowing of 70% of the maximal luminal diameter

D. Progressive renal artery narrowing >50% of the maximal luminal diameter

2. Which ONE of the following is true regarding the role of screening for in-stent stenosis after renal artery stenting?

A. Baseline duplex ultrasonography should be performed as soon as possible

B. Duplex ultrasonography should only be done for clinical symptoms

C. CT angiography is the test of choice, and should be done as soon as possible

D. CT angiography should only be done for clinical symptoms

3. Which of the following tests would NOT be useful in screening for in-stent stenosis after renal artery stenting?

A. Duplex ultrasonography

B. CT angiography

C. Magnetic resonance angiography

D. Renal artery angiography

4. A 68-year old man was referred for evaluation of resistant hypertension. A Doppler ultrasound demonstrates hemodynamically significant right RAS, and a percutaneous right renal artery stent was placed. Duplex ultrasonography performed 6 months later revealed doubling in peak systolic velocity from baseline at the site of the stent. There is no change in his kidney function or blood pressure on the same medical regimen. What is the most appropriate next step?

A. Closer clinical and duplex US surveillance

B. Renal angiography with in-stent stenosis treatment

C. Start oral anticoagulation

D. CT angiography to confirm the finding

5. All of the following factors would carry an increased risk of in-stent stenosis following renal artery stent placement EXCEPT:

A. Smaller vessel diameter

B. Male sex

C. Stent type

D. No statin therapy

E. Elevated BMI

Post prepared Dr. Abdo Asmar, University of Central Florida College of Medicine, and Dr. Kenar Jhaveri, eAJKD Blog Editor.

To see answers, please click here.

To view the article abstract or full-text (subscription required), please visit AJKD.org.