Doppler velocimetry of maternal renal interlobar arteries in pregnancy-induced hypertension

To evaluate whether Doppler velocimetry of maternal renal interlobar arteries is altered in patients with hypertensive disorders of pregnancy (PIH).

Flow velocity waveforms (FVWs) were obtained, by means of color and pulsed Doppler ultrasound, from the renal artery and two interlobar arteries in the right kidney of 46 normal pregnant women and 10 patients with PIH between 20 and 39 weeks' gestation. Statistical analyses of resistance indices (RI) were performed by regression analysis, paired and unpaired t-tests.

RI values of renal and interlobar arteries in normal patients did not change significantly with gestational age. Interlobar arteries had significantly lower RI values than corresponding main renal arteries (T = 3.88, P < 0.001). No significant differences in FVWs of renal (T = 1.86, P = 0.068) and interlobar arteries (T = 0.85, P = 0.399) were found between normal and hypertensive patients. A statistical power analysis confirmed that our sample size was sufficient to detect a difference in RI of 0.10, with alpha = 0.05 and beta = 0.80.

FVWs of the renal and interlobar arteries are not altered in patients with mild PIH.