SEMIQUANTITATIVE EVALUATION OF INTRARENAL ARTERIAL DOPPLER SPECTRA INHEALTHY-ADULTS

In a prospective study on 60 healthy adults, 38 men and 22 women (age range, 20-70 years), semiquantitative analyses of intrarenal arterial Doppler waveforms were performed by means of colour duplex sonography under standardised conditions. Furthermore, the effect of heart rate o n calculation of renoparenchyml atterial Doppler spectra was evaluated . A total of 115 normal kidneys were studied, giving the following nor mal values (mean +/- standard deviation): resistance index (RI): 57+/- 4.5%, pulsatility index (PI): 89+/-13%, pulsatile flow index (PFI): 65 +/-6 %. There were no different values for men and women. The normal r enal resistance indices, however, were found to be age dependent, with increasing trend of RI and PI and decreasing trend of PFI with increa sing age, most probably due to a corresponding increase of vascular re sistance and mean arterial blood pressure. In an experimental study, w e found a significant decrease of RI and PI and an increase of PFI par alleling the increase of heart rate. To eliminate the effect of heart rate on renal resistance indices, i.e. for interindividual comparison of data or intraindividual follow-up, measurements of indices can be c orrected for a standardised heart rate by using regression equations. The results of our studies emphasise that interpretations of semiquant itative calculations of renal Doppler waveforms should be performed in consideration of extrarenal factors, for example the patient's age an d heart rate.