OS047. Quantification of placental vascularization in a rabbit model ofIUGR with three-dimensional power doppler angiography.

INTRODUCTION: Placental dysfunction is known to be a major cause of pregnancy complications, such as perinatal loss, preeclampsia, and intrauterine growth restriction (IUGR). Inadequate remodeling of the spiral arteries resulting in decreased blood flowto the placenta has been implicated in the pathophysiology of preeclampsia and IUGR. 3D power Doppler angiography (PDA) is a noninvasive and safe way to study blood flow within an organ or region of interest. The aim of this study was to evaluate PDA as a method to quantify placental perfusion in a pharmacological rabbit model of vascular IUGR induced by inhibition of NO synthesis.

OBJECTIVES: Our objective was to evaluate the 3D power Doppler angiography (PDA) in terms of feasibility and ability to detect placental hypo-perfusion in an experimental rabbit model of intrauterine growth restriction (IUGR).

METHODS: Fourteen pregnant females were treated with NG-nitro-L-arginine methylester (L-NAME), a nitric oxide synthase inhibitor, from day 24 to day 28 of gestation, to induce an IUGR. Concomitantly, 8 pregnant rabbits were used as controls. On day 28, 3D power Doppler indices were quantified in each uteroplacental unit.

RESULTS: A total number of 180 live fetuses were obtained, 180 from the L-NAME group and 72 from the control group. G28 fetal weight was significantly lower in the L-NAME group than in the control group (27.40±0.55g vs 33.14±0.62g,p<0.0001). In the L-Name group the vascularization index (VI) was significantly lower than in the control group (2.6 [1.4;6.0] vs 7.6 [3.5;12.6],p<0.05). Similar results were obtained for the Flow Index (FI) and the Vascularization Flow Index (VFI). The number of fetuses considered as small for gestational age (SGA;weight<10th centile) was significantly higher in the L-NAME group than in the control group (47/108 vs 7/72,p<0.0001). The VI was significantly lower in the SGA group than in the eutrophic group (3.46 [0.46;5.9] vs 7.50 [4.22;10.9] p<0.05). Similar results were obtained for FI and VFI.

CONCLUSIONS: This experiment study demonstrates that quantitative 3D PDA indices are sensitive enough to detect placental vascular insufficiency in an experimental model of IUGR.