The performance of renal duplex ultrasonography for the detection of hemodynamically significant renal artery stenosis

Abstract

The value of renal duplex ultrasonography for the detection of angiographical renal artery stenosis (RAS) has been demonstrated in many clinical studies. None of the published studies, however, have adequately scrutinized the performance of this modality for the detection of hemodynamically significant RAS. The purpose of this study is to investigate the correlation and accuracy between renal duplex parameters and translesional pressure gradient (TLPG). A total of 60 patients, with 75 stenotic lesions in the renal arteries determined by angiography, underwent duplex ultrasonography before angiography and the measurement of TLPG using a 0.014'' pressure wire in the single setting of angiography were prospectively included. Peak systolic velocity (PSV) in the renal artery and a ratio of PSV in the renal artery to the aorta (RAR) were examined as duplex ultrasonography parameters. Angiographical stenosis was evaluated by percent diameter stenosis (%DS) derived from quantitative angiographic analysis. The correlation with TLPG proved to be stronger in the following order, PSV (r = 0.743, P < 0.001), %DS (r = 0.701, P < 0.001), and RAR (r = 0.572, P < 0.001). The best performing parameter for TLPG of 20 mm Hg was revealed to be PSV, as the areas under the receiver operator characteristics curves using %DS, PSV, and RAR were 0.888, 0.939, and 0.834, respectively. A PSV cutoff value of 219 cm/sec provided the best predictive value with a sensitivity of 89%, a specificity of 89%, and an accuracy of 89%. The positive predictive value was 83% and the negative predictive value was 93%. The measurement of PSV is not only noninvasive but also highly accurate in detecting patients who have hemodynamically significant RAS. The authors emphasize that an enthusiastic application of renal duplex ultrasonography, particularly the measurement of PSV, is warranted.