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The present study investigates prospectively the validity and accuracy of the simplified Bernoulli equation in the duplex-derived determination of pressure gradients across iliac artery stenoses in patients with occlusive artery disease. In 28 patients (age range, 38 to 76 years; mean, 53 years) with short iliac artery stenoses, we obtained both duplex scan stenotic jet velocity and catheter pressure measurements. Mean and maximum pressure gradients were determined by both methods, as was the peak-to-peak catheter gradient. The correlation between the duplex-determined and nonsimultaneously measured catheter mean pressure gradients was r = 0.77 (standard error of the estimate [SEE] = 5 mm Hg), that between the duplex-derived and catheter-determined maximum pressure gradients was r = 0.80 (SEE = 10 mm Hg), and that between maximum duplex-determined and peak-to-peak catheter gradient was r = 0.76 (SEE = 12 mm Hg). The peak-to-peak catheter gradient was significantly lower than the maximum duplex-derived gradient (46 versus 53 mm Hg, P < 0.05). Duplex-determined mean pressure gradient decreased from 15 +/- 6 to 3 +/- 1 mm Hg after balloon angioplasty of the iliac stenoses. Duplex scan can be used to predict pressure gradients across short iliac artery stenoses, provided that errors caused by angle malcompensation are prevented.

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The assessment of the renal arteries is particularly important in the detection of a renovascular cause of the arterial hypertension. The purpose of the present study was twofold: to evaluate the accuracy of duplex scanning in non-invasively diagnosing renal artery stenoses in hypertensive patients, and to determine the results of transluminal angioplasty of renal artery stenoses as assessed by duplex scanning. In 76 patients with arterial hyertension, 170 renal arteries (18 kidneys supplied by two renal arteries) were examined by both duplex scanning and angiography (DSA in intraarterial and intravenous technique, and conventional arteriography). Peak systolic and end-diastolic flow velocity parameters as well as the Pourcelot-index were determined in the proximal renal artery and compared with the indendently performed angiography. In 102 angiographically proven normal renal arteries, mean +/- SD peak systolic and end-diastolic velocity values were 84.7 +/- 13.9 cm/s and 31.2 +/- 7.8 cm/s, respectively, with a Pourcelot-index of 0.66 +/- 0.07. For detecting renal artery stenoses greater than 50%, duplex scanning had a sensitivity of 86%, and a specificity of 83% for a systolic peak velocity of 140 cm/s and more in the renal artery. In 13 patients with 14 stenosed renal arteries, duplex scanning and intraarterial DSA densitometry were performed before and after transluminal angioplasty of the renal artery stenoses. There was fairly good agreement between transstenotic peak systolic velocities and densitometrically determined degrees of stenosis in the renal artery (r = 0.84). These results show that duplex scanning is an accurate noninvasive diagnostic tool in detecting proximal renal artery stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)