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.