Hemodynamics of the renal artery and descending aorta in fetuses with renal disease using color Doppler ultrasound--longitudinal comparison to normal fetuses.

Objective: To examine the hemodynamic values of the renal artery (RA) and descending aorta (DA) in normal fetuses, and to compare these values to those of fetuses with renal disease, thus evaluating the usefulness of hemodynamic analysis for the diagnosis of fetal renal disease. Materials and methods: We examined 46 normal fetuses and 15 fetuses with renal disease (six cases of polycystic kidney (PCK) and nine cases of hydronephrosis). We measured the maximum systolic velocity (V max ) of the RA and DA using color Doppler. Measurements were made five times, from the 20th to the 40th week, in both the control and the renal disease group. Results: In the fetuses with PCK (Potter's syndrome) that died postpartum from non-functional kidneys, the V max of the RA and DA in the 35th week were 13 cm/s and 25.4 cm/s, respectively. In the fetus with PCK (Trisomy 9) that died due to non-functional kidneys in the 34th week, the values were 13.3 cm/s and 29.6 cm/s, respectively. These values were well below those of the normal group: more than 1.5 SD below the mean. In two fetuses from the nine with hydronephrosis that had a unilateral non-functional kidney, the RA did not clearly show identifiable blood flow. Conclusions: The V max of the RA and DA in fetuses with renal disease correlates with fetal kidney function, particularly the RA V max . V max of 1.5 SD below the mean should be the lower normal limit.