Renal artery duplex ultrasonography: a reliable new screening test for functionally significant renal artery stenosis

1. Renal artery duplex ultrasonography (RADU) has recently become available as a rapid, relatively inexpensive, non-invasive screening test for renal artery stenosis causing renovascular hypertension. 2. We compared the sensitivity of RADU with that of computerized nuclear renography (CNR) in 16 patients with renovascular hypertension. All had lateralizing renal venous renin ratio (RVRR) studies, 15 had renal artery stenosis (RAS) on angiography and one had unilateral chronic parenchymal renal disease (CPRD). 3. We found RADU to be at least as reliable as CNR with sensitivities of 100% and 93.7%, respectively. Neither RADU nor CNR was successful (sensitivity 25% and 0%, respectively) in detecting minor, functionally insignificant contralateral renal artery stenosis in four patients, two of whom had multiple small renal arteries--a recognized difficulty in the use of RADU. 4. After successful (RVRR became negative) therapeutic intervention in two patients with RAS (dilatation one, surgery one), RADU changed from positive to negative and may therefore be a useful alternative to repeat angiography in this setting. 5. Performed in conjunction with renal parenchymal B mode ultrasound, RADU correctly identified the presence of CPRD in one patient.