Doppler Measurement of Renal Interlobar Vein Impedance Index in Uncomplicated and Preeclamptic Pregnancies

Abstract

Objective: To define normal values of Renal interlobar vein impedance index (RIVI) throughout gestation, as a reference to RIVI in preeclampsia (PE). Methods: Longitudinal evaluation of 20 uncomplicated pregnancies (UP) by standard renal duplex scan, every 4 weeks during pregnancy and postpartum. Comparison of RIVI between 40 PE and UP, and plotting of PE values against the normal reference range at corresponding gestation. Results: In PE, RIVI is significantly higher than in UP, the difference being larger at the left side and in cases of preeclampsia remote from term. Conclusion: Increase of RIVI in women with PE is gestation-dependant.

Keywords:

• Renal interlobar veins
• Venous impedance index
• Preeclampsia
• Doppler
• Venous tone