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378: Hepatic artery Doppler in IUGR fetuses

      Objective

      Animal studies have reported that in IUGR fetuses there is a redistribution of blood flow from the liver to the brain, heart and adrenal gland, which occurs because a large amount of umbilical blood flow, proportional to the degree of fetal hypoxia, bypasses the liver through the ductus venosus. Only a few studies have focused on the arterial hepatic blood flow. The aim of this study was to assess flow velocity waveforms of the main hepatic artery (HA) in IUGR fetuses.

      Study Design

      The main HA pulsatility index (PI) was determined in 33 IUGR fetuses (EFW<10th percentile and abnormal umbilical artery PI). The main HA PI was defined as abnormal if the values were above or below the reference range established in normal fetuses for gestational age (GA). The HA PI was obtained within 24 hours from delivery or fetal demise and was correlated with perinatal outcome [fetal or neonatal (≤4 weeks after birth) demise]. Fisher's exact test was used for statistical analysis.

      Results

      The median GA at the time of the delivery was 27.2 weeks (range: 23-33 weeks). Twenty-one fetuses had a PI value below the lower limit of normal, 12 fetuses had a value within the normal reference range, and none of the fetuses had a value above the upper limit of normal. Among fetuses with an abnormal HA PI, there were 6 fetal and 7 neonatal demises (p<0.05). Two fetuses with a normal HA PI died either in-utero or after birth. An abnormal HA PI had a sensitivity, specificity, positive and negative predictive value of 87% (95% CI: 62-96%), 56% (95% CI: 34-75%), 66% (95% CI: 33-80%), and 83% (95% CI: 63-96%), respectively, for predicting perinatal death. The positive likelihood ratio was 2.00.

      Conclusion

      This study indicates that there is an abnormal HA PI in IUGR fetuses and it is associated with an increased risk of perinatal death. The changes seen at the HA PI are similar to those reported for other fetal organs, such as the brain, and they suggest that there is a lower arterial hepatic vascular resistance and, consequently, an increased hepatic artery blood flow in IUGR fetuses.