THE UTILITY OF DUPLEX ULTRASOUND SCANNING OF THE RENAL-ARTERIES FOR DIAGNOSING SIGNIFICANT RENAL-ARTERY STENOSIS

Objective: To determine the utility of duplex ultrasound scanning of t he renal arteries in identifying patients with renal artery stenosis o f 60% or more and in excluding patients with either normal renal arter ies or renal artery stenosis of less than 60%. Design: A prospective, blinded study. Setting: Large tertiary referral center. Patients: 102 consecutive patients (44 men and 58 women with a mean age [+/-SD] of 6 3.3 +/- 13.4 years) who had both duplex ultrasound scanning of the ren al arteries and renal arteriography. All patients who were studied had hypertension that was difficult to control, unexplained azotemia, or associated peripheral vascular disease (alone or in combination), givi ng them a high pretest likelihood of renovascular disease. Main Outcom e Measurements: Peak systolic and end diastolic velocities, renal-aort ic ratios, resistive index, and kidney sizes. Results: Sixty-two of 63 arteries with stenosis of less than 60% using arteriography were corr ectly identified by duplex ultrasound scanning. Thirty-one of 32 arter ies with 60% to 79% stenosis using arteriography were correctly identi fied as having 60% to 99% stenosis on duplex ultrasound, whereas 67 of 69 arteries with 80% to 99% stenosis on arteriography were correctly identified as having 60% to 99% stenosis on ultrasound. Twenty-two of 23 arteries with total occlusion on arteriography were correctly ident ified by duplex ultrasound. The overall sensitivity of duplex ultrasou nd compared with arteriography was 0.98, the specificity was 0.98, the positive predictive value was 0.99, and the negative predictive value was 0.97. Conclusion: Duplex ultrasound scanning of the renal arterie s is an ideal screening test because it is noninvasive and can predict the presence or absence of renal artery stenosis with a high degree o f accuracy.