Fetal Hemodynamic Profile in Splanchnic Vessels Centralization Mechanism Analysis
Authors: Mercé LT , Troyano JM , Rosa M Alvarez de la , Padilla A , Ces L 
Published: June 2010

Abstract
We compared the hemodynamic profiles of abdominal visceral vessels in physiological and pathological conditions as well as peripheral vessels away from the visceral area.
The resistance index (RI) was monitored in the renal, celiac trunk, gastric, pancreatic and spleen artery linearly in a bi-monthly bases, in 159 physiological pregnancies.
On the other hand an additional group of 47 pregnancies between the 26th and the 40th weeks of gestation were monitored for differences in RI from the renal artery in both right and left kidney. The RI from the right kidney was always lower than in the left kidney, a difference that was nonetheless not statistically significant.
Concerning hemodynamic responses to fetal pathology, kidney hemodynamics were surveyed in two samples of fetuses displaying IUGR. The first sample was made up of a total of 72 fetuses showing IUGR associated with euamnion, while the second sample consisted on 39 IUGR fetuses showing oligohydramnion.
The renal artery in IUGR-euamnion fetuses yielded RI values similar to those recorded from healthy kidneys.
In contrast, in IUGR-oligohydramnion cases, the RI was markedly restrictive when compared to that of healthy and IUGR-euamnion situations.
Besides we investigated in 49 cases the hemodynamic behavior in macrosomic fetuses in diabetes pregnancy, between 32nd to 38th week.
Vascular resistance affecting blood flows in fetal kidneys is lower in macrosomic fetuses with gestational diabetes than in normal gestations with statistical significance.
In cases of kidney parenchyma pathology 49 pregnancies presented severe hydronephrosis, 37 pregnancies had light hydronephrosis and 22 pregnancies were diagnosed as cases of corticomedullar dysplasia associated with oligohydramnion.
RI values from the renal artery were higher in cases of severe hydronephrosis than in cases of light hydronephrosis. This difference was statistically significant.
The RI obtained from cases with mild hydronephrosis was fairly similar to that of healthy kidneys
In contrast, the RI values recorded from fetuses having an association of corticomedullar dysplasia and oligohydramnion were the highest among the three pathological groups.
Regarding splanchnic and other abdominal viscera, celiac trunk's spectral profile were characterized by a low resistance, and showed a gradual increase in diastolic velocity throughout gestation.
The gastric artery displayed a gradually declining vascular resistance through pregnancy.
Hemodynamic records from the pancreatic artery are restrictive over the whole period of gestation and only the maximum systolic peak can be subjected to measurement.
The spleen artery showed a low diastolic resistance which declined markedly through gestation, even in situations of chronic fetal compromise, this artery experienced increased vascularization in response to stress, a vascular trait that was found to be unique for this anatomical area.
The flowmetric resistance in the spleen artery was lower than in the renal artery and than the rest of the abdominal vessels studied.
The femoral artery had a very restrictive hemodynamic profile, which was characterized by the lack of a telediastolic flow.
These data suggests that the fetal blood stores are located in the extremities rather than in visceral areas.
The monitoring of the hemodynamic patterns emerging from the vessel complex studied here, has allowed an insight into the mechanism of vascular centralization in response to perturbing conditions, this mechanism should be regarded as a kind of functional and nutritional autoregulative reaction of the visceral set involved.