Maternal renal artery Doppler flow-velocity waveform in preeclampsia. A preliminary report.

By use of duplex Doppler ultrasonography, we preliminarily studied 30 normal pregnancies (control group) and 30 patients with preeclampsia (study group) before treatment. The peak systolic flow height to end diastolic flow height (S/D) ratio of the maternal right and left renal arteries of both groups were compared and analyzed. The results showed that there were no significant differences between the right and left renal arteries in either group, but unexpectedly the S/D ratio of the renal artery on both sides in preeclamptic patients was significantly lower than in normal pregnant women (mean +/- SD, 2.07 +/- .12 vs. 2.41 +/- .12, respectively, P < .001). The lower S/D ratio of the renal artery may reflect a decrease in renovascular resistance and an increase in renal perfusion. These findings were the reverse of what might be expected from an elevated vascular resistance and hypoperfusion model.