Intravascular Doppler technique for monitoring renal venous blood flow in man

Background: To measure renal blood flow (RBF) from the renal veins in men using the intravascular Doppler technique (IVD). Methods: In nine hypertensive male patients (age 46-64 years) undergoing diagnostic renal artery angiography and renal vein catheterization to determine plasma renin activity (PRA), a 3F Doppler catheter was positioned in the renal veins using a 7F guide catheter with a "basket" shaped tip. The radiopaque sectors of the catheter, leaning against the vessel wall, serve to measure the internal diameter of renal veins, and therefore to calculate RBF, by multiplying renal vein cross-sectional area by mean blood flow velocity. The resulting RBF from the left and right renal veins were compared with those obtained by the local thermodilution method (TD). Results. We found good agreement (Bland and Altman's method) between the RBF measurements made with IVD (ranging from 46 mL/min to 1220 mL/min) and with the TD technique (45-1030 mL/min) (mean bias, 1320 mL/min, 95% CI -54.77 to 28.77 mL/min). In stenotic kidneys a significant correlation was found between the renal vein PRA and RBF calculated with both methods (IVD: r = 0.96, p = 0.002; TD: r = 0.90, p = 0.01). Conclusions. The IVD technique applied to the venous side of the renal circulation provides a simple and reliable method for separate measurement of RBF in kidneys with and without renal artery stenosis.