Reproducibility and repeatability of maternal venous Doppler flow measurements in renal interlobar and hepatic veins

Abstract

Renal vascular studies can be performed using ultrasound and duplex color flow. No signficant changes in renal arterial Doppler flow have been observed, but Doppler flow of the interlobar renal veins was reported to change markedly during pregnancy. Compared to non-pregnant women, the renal interlobar vein venous impedance index (RIVI) was lower in pregnant individuals, and this effect was more pronounced in the third than in the second trimester. The RIVI was also higher in preëclampsia than in uncomplicated pregnancies. Hepatic vein (HV) Doppler waveforms also change significantly during pregnancy. A spectrum of venous HV Doppler waveforms has been observed in the course of both uneventful pregnancies and those complicated with preeclampsia. Characteristics of normal HV Doppler waveforms (A,X,V and Y) resemble those observed at the inferior Vena Cava level and relate to the cardiac-cycle dependent changes of the right atrium. Despite this potential clinical application, there is a lack of data in the literature on the reproducibility and repeatability of Doppler resistance and velocimetry measurements of renal interlobar veins and hepatic veins. The aim of this study was to assess intra- and interobserver variability of Doppler flow velocity measurements of renal and hepatic veins in pregnancy.