Hemodynamic analysis of Hyrtl anastomosis in human placenta.
Am J Physiol Regul Integr Comp Physiol
; 292(2): R977-82, 2007 Feb.
Article
em En
| MEDLINE
| ID: mdl-17038439
ABSTRACT
The Hyrtl anastomosis is a common connection between the umbilical arteries near the cord insertion in most human placentas. It has been speculated that it equalizes the blood pressure between the territories supplied by the umbilical arteries. However, its functional role in the regulation and distribution of fetal blood flow to the placenta has not yet been explored. A computational model has been developed for quantitative analysis of hemodynamic characteristic of the Hyrtl anastomosis in cases of discordant blood flow in the umbilical arteries. Simulations were performed for cases of either increased placental resistance at the downstream end or reduced arterial blood flow due to some pathologies upstream of one of the arteries. The results indicate that when placental territories of one artery impose increased resistance to fetal blood flow, the Hyrtl anastomosis redistributes the blood flow into the second artery to reduce the large pressure gradients that are developed in the affected artery. When one of the arteries conducts a smaller blood flow into the placenta and a relatively smaller pressure gradient is developed, the Hyrtl anastomosis rebuilds the pressure gradients in the affected artery and redistributes blood flow from the unaffected artery to the affected one to improve placental perfusion. In conclusion, the Hyrtl anastomosis plays the role of either a safety valve or a pressure stabilizer between the umbilical arteries at the placental insertion.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Placenta
/
Artérias Umbilicais
/
Circulação Placentária
/
Feto
Tipo de estudo:
Prognostic_studies
Limite:
Adult
/
Female
/
Humans
/
Pregnancy
Idioma:
En
Revista:
Am J Physiol Regul Integr Comp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Israel