Hepatic arterial buffer response: activation in donor fetuses and the effect of laser ablation of intertwin anastomosis

OBJECTIVES

Hepatic arterial buffer response (HABR) is an important defence mechanism for maintaining liver blood flow. It is suspected that HABR is active in monochorionic diamniotic twins (MCDA) with twin-to-twin transfusion syndrome (TTTS) where donor compensates a setting of volume depletion and the recipient an overload. The present study investigates whether in TTTS, HABR is active in donor and/or recipient individually and try to determine if the activation of HABR is a direct response to TTTS.

METHODS

Hepatic artery (HA) peak systolic velocity (PSV) was measured in normal MCDA fetuses and TTTS. Correlation with relevant fetal Dopplers and characteristics were determined. Z-scores for HA-PSV (HAV-Z) were calculated and its association with TTTS in donors and recipients were determined as well as changes in HAV-Z after laser treatment.

RESULTS

In this study 118 MCDA were included, 61.9 % normal and 38.1 % TTTS. Of the TTTS 22 required laser treatment. A total of 382 scans were performed in normal group and 155 in TTTS. Our data demonstrates that in donors HAV-Z was 2.4 Z-scores higher compared to normal fetuses (β=2.429 95 % CI 1.887, 2.971; p<0.001) and after laser treatment HAV-Z reduced (β=-1.829 95 % CI -2.593, -1.064; p<0.001). There was no significant difference between recipients and normal (β=-0.092 95 % CI -0.633, 0.449; p=0.738).

CONCLUSIONS

HABR is active in TTTS, promoting an increased hepatic blood flow in donors. The activation is direct response to TTTS as shown by the reduction in HAV-Z after laser. This finding provides important insights into the pathophysiology of TTTS.

Nasal bone in fetal aneuploidy risk assessment: are they independent markers in the first and second trimesters?

OBJECTIVES

In the mid-trimester ultrasound, nasal bone (NB) length can be used to correct the a priori risk for trisomy 21. Our study aims to evaluate if there is a correlation between an absent NB in the first trimester and a hypoplastic NB in the second trimester.

METHODS

Our two year retrospective analysis of data derived from routine clinical practice. Single euploid fetuses were included. The NB was assessed in both trimesters according to international guidelines and transformed into categorical variables. Logistic regression was performed in order to accomplish our main objective.

RESULTS

From the 759 normal pregnancies included, 45 (5.93%) had abnormal NB in the first trimester and 23 (3%) in the second trimester. Eleven cases (47.8%) of the abnormal NB in the second trimester were abnormal in the 11-14 weeks scan. After the diagnosis of an absent NB in the first trimester the odds ratio (OR) for a hypoplastic NB in the second trimester is 18.926 (7.791-45.977; p-value <0.01).

CONCLUSIONS

Our data suggest a strong association between the NB in the first and in the second trimester in normal euploid fetuses. This is important information to consider when counseling patients on the basis of this ultrasound marker.

Association between first-trimester maternal serum pregnancy-associated plasma protein-A and obstetric complications

OBJECTIVE

This study aimed to investigate the relationship between maternal serum pregnancy-associated plasma protein-A (PAPP-A) in the first trimester of pregnancy and the development of preeclampsia (PE), early PE, small-for-gestational age (SGA) fetus and preterm delivery (PD).

METHOD

This is a retrospective study of 12,355 pregnant women that delivered between 2008 and 2011. We define the first, third and fifth percentiles of maternal serum PAPP-A multiples of the median (MoM). The primary outcome measures were the occurrence of PE, early PE (PE requiring delivery before 34 weeks), SGA fetus (birth weight < 5th centile) and PD. The Mann-Whitney U-test and chi-squared test were used to analyze continuous and dichotomous variables, respectively.

RESULTS

Maternal serum PAPP-A was significantly lower in women with PE, early PE, SGA fetus and PD (0.91, 0.74, 0.80 and 0.84 MoM, respectively) than in the study population (0.99 MoM) (p < 0.05). The lower the MoM percentile of PAPP-A, the higher are the odds ratio (OR) to develop PE, early PE, SGA fetus and PD.

CONCLUSIONS

Maternal serum PAPP-A levels are lower in women who develop preeclampsia, those with SGA fetus and those who deliver preterm. However, on its own, maternal serum PAPP-A performs poorly (OR for PE between 1.76 and 2.41 with the lower percentile of PAPP-A) as a screening test for these conditions.