Modification of placental blood flow by hemodilution in high-risk pregnancies:: Discrimination between responder and non-responder using power Doppler sonography

Aim: Can hemodilution therapy change the intraplacental blood flow in high-risk pregnancies and is it possible to demonstrate this non-invasively and in vivo? Methods: 32 pregnant women (hematocrit > 38%, abdominal circumference < 5th centile and/ or Doppler flow > 60th centile for the umbilical and > 90th centile for the uterine artery by sonographic measurement) underwent hemodilution therapy (1-4 cycles of 500 ml hydroxyethyl starch 10%/500ml Ringer lactate daily for two weeks) at 29 weeks (median). Power Doppler ultrasound was performed before and 90 minutes after the therapy. The setting of the machine was always the same. The Doppler gate was placed over the parenchymatous part of the placenta excluding the umbilical cord vessels as well as the vessels of the chorionic and basal plates. The dispersion coefficient (standard deviation of local mean values/global mean of intensity-weighted distribution of colour pixels in the 8 x 4 block), the "Inverse Difference Moment" and the "Second Angular Moment" of the co-occurrence matrix were calculated using special software. Results: In 15/32 cases the outcome of pregnancy was sufficient (median gestational age 39 weeks, median birthweight 2890 g). All parameters changed significantly. In 17/32 cases premature delivery occurred because of foetal distress (median gestational age 33 weeks, median birthweight 1690 g). None of the parameters showed significant changes. Conclusion: In cases of sufficient outcome blood flow we were able the demonstrate an improved blood flow in the sense of our analysis.