Objective: (1) to develop the in-vitro simulation of fetal blood flow in the whole ex-vivo placenta, (2) to analyze the relationships between the flow rate and the medical Doppler indexes in the placental vasculature.
Methods: Ex-vivo perfusion of the placental vasculature was performed on 17 full‑term singleton placentas, which were obtained immediately after delivery. S/D ratio was measured for each placenta at the insertion site and at different dichotomous generations of chorionic arteries as well. Chorionic arteries were oblitarated from IVth to Ist generations and Doppler ultrasound (DUS) measurements have been performed after each occlusion.
Results: The results showed that the S/D ratio of the placenta has higher indices at the cord insertion (2.66 ± 0.47) and lower ones at further generations of the chorionic arteries (measured till IVth generation). Only when all four generations were occluded the umbilical artery S/D ratio was changed.
Conclusions: (1) We developed the first in-vitro model of the human placental perfusion to explore the interrelationship between umbilical artery blood flow (measured by S/D ratio) and the placental vascular pathology. (2) Our results showed that only 50% occlusion of the placental arterial system with its downstream vascular bed can be detectable by DUS and causes a sharp increase of S/D ratio.
Authors:
Zoya Gordon1, Liliya Glaubach2, David Elad3, Uri Zaretzky3, Ariel J. Jaffa1, 4
1Ultrasound Unit in Obstetrics and Gynecology, Lis Maternity Hospital, Tel-Aviv Medical Center, Tel-Aviv 64239, Israel.
2Department of Obstetrics and Gynecology, Hillel -Yaffo Medical Center, Hadera, Israel.
3Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Tel-Aviv 69978, Israel.
4Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel.