Renal artery flow velocity analysis: a sensitive measure of experimental and clinical renovascular resistance.

Renal artery flow velocity analysis has recently been shown to be an indicator of renal parenchymal resistance. Noninvasive measurement of graded renovascular resistance is investigated with experimental models of canine gel microsphere embolization (n = 15), canine renal allografts (n = 4), and clinical renal allografts (n = 6). Intraoperative pulsed Doppler recordings were made on the canine renal artery simultaneous to pressure and flow measurements with sequentially increasing resistance. Transcutaneous echo-Doppler (Duplex) measurements were made on acute patient renal allografts following chemical estimation of renal function. Noninvasive prediction of renovascular resistance in the experimental canine gel microsphere and allograft models correlates with invasive recordings of volume flow (pressure nearly constant), r = 0.93 and r = 0.90, respectively. Duplex estimation of clinical renal allograft resistance and chemical prediction of renal function are similarly interdependent, r = 0.81. Directional arterial flow analysis may be a useful indicator of native and acute allograft renovascular resistance.