The Placenta in Congenital Heart Disease: Form, Function and Outcomes

Four novel types of placental villous trees: Insights from SlowflowHD ultrasound imaging into placental microvascular architecture in congenital heart disease

OBJECTIVE

Placental vascular development is critical for maternal-fetal exchange, and altered fetal cardiovascular physiology in congenital heart disease (CHD) may impact placental circulation. This study aimed to assess whether SlowflowHD imaging technology could qualitatively evaluate alterations in placental vascular structure in CHD.

METHODS

A cross-sectional study was conducted using SlowflowHD to image placental vasculature in 215 fetuses, normal (n = 106) and CHD (n = 109) including critical CHD (CCHD) (n = 66) and other fetal heart disease (FHD) (n = 43). SlowflowHD provided two-dimensional (2D) and three-dimensional (3D) imaging of placental villous tree structures. Differences in display rates and distribution characteristics of placental villous trees were analyzed between the normal, CCHD, and FHD groups.

RESULTS

SlowflowHD imaging technology demonstrated high sensitivity in visualizing placental vascular structures, with overall display rates of 95.5%-100%. Primary, secondary, and tertiary villi were visualized with rates of 95.5%-100%, 69.7%-97.7%, and 34.8%-88.7%, respectively. Four distinct placental villous tree types (types 0-3) were identified, exhibiting different distribution characteristics. The composition ratios of these types differed significantly between normal and CCHD fetuses, as well as between CCHD and FHD groups (P < 0.05).

CONCLUSION

SlowflowHD imaging technology effectively identifies and characterizes placental villous tree structures. Placental villous trees in CCHD fetuses display sparser distribution patterns compared with normal fetuses, highlighting potential implications for maternal-fetal exchange in CHD.

Placental and Fetal In Utero Growth Among Fetuses With Congenital Heart Disease

Importance

At birth, neonates with congenital heart disease (CHD) have smaller placentas, lower birth weight, and smaller head circumferences compared with healthy neonates. The onset of feto-placental growth disturbances, however, is not well known.

Objective

To compare fetal body volumes, assess differences in the fetal to placental volume ratios (placental growth relative to the fetus), and investigate the association between in utero fetal body and total brain volume in fetuses with and without CHD.

Design, Setting, and Participants

This case-control study enrolled pregnant women with a fetal diagnosis of CHD and those with healthy pregnancies at Children's National Hospital in Washington, DC, from April 2018 to July 2023. Fetal magnetic resonance imaging was obtained up to 2 time points during pregnancy. The fetal to placental ratio was calculated using 3-dimensional magnetic resonance image fetal body volumes and placental volumes.

Exposure

In utero environment CHD.

Main Outcomes and Measures

The main outcomes were the trajectories of body, brain, and placental volumetric growth in fetuses with CHD and in control fetuses. Generalized linear regression and mixed-effects models were applied to identify associations for fetal body volume and fetal to placental volume ratios between CHD and control groups adjusting for fetal sex and gestational age at the time of the magnetic resonance imaging scan.

Results

The study included 108 fetuses (59 male [54.6%]), of which 55 were in the healthy control group (with 55 scans), and 53 had CHD (with 77 scans). Fetal body volumes in fetuses with CHD were smaller compared with control fetuses (β = -193.60 [SE, 44.42]; P < .001) with larger fetal to placental volume ratios (β = 0.23 [SE, 0.10]; P = .02). The total brain volume was smaller in fetuses with CHD compared with control fetuses (β = -10.87 [SE, 5.09]; P = .04).

Conclusions and Relevance

In this case-control study of fetuses with and without CHD, those with CHD demonstrated impaired fetal body growth with higher fetal to placental volume ratios and smaller total brain volume, suggesting that placental failure was associated with growth disturbances in CHD, as demonstrated by the large fetal to placental volume ratios. Additional studies should assess the onset and progression of placental dysfunction and how the timing of placental failure may contribute to neurodevelopmental disability in survivors of CHD.

Visualization of placental villi: Three-dimensional ultrasound imaging shows coral-like placental villous trees

We introduce a new microflow imaging technique, which can show the blood perfusion and morphological structure of placental villi.

Bedside monitoring tools and advanced signal processing approaches to monitor critically-ill infants

There is a substantial body of literature that supports neonatal monitoring and signal analysis of the collected data to provide valuable insights for improving patient clinical care and to inform new research studies. This comprehensive monitoring approach extends beyond the collection of conventional vital signs to include the acquisition of continuous waveform data from patient monitors and other bedside medical devices. This paper discusses the necessary infrastructure for waveform retrieval from bedside monitors, and explores options provided by leading healthcare companies, third-party vendors or academic research teams to implement scalable monitoring systems across entire critical care units. Additionally, we discuss the application of advanced signal processing that transcend traditional statistics, including heart rate variability in both the time- and frequency-domains, spectral analysis of EEG, and cerebral pressure autoregulation. The infrastructures and signal processing techniques outlined here are indispensable tools for intensivists, empowering them to enhance care for critically ill infants. In addition, we briefly address the emergence of advanced tools for fetal monitoring.

Placental-Heart Axis: An Evolutionary Perspective

To maintain its development, the growing fetus is directly dependent on the placenta, an organ that acts as both a modulator and mediator. As an essential component of pregnancy that is derived from both maternal and fetal tissues, the placenta facilitates the passage of all oxygen and nutrients from the expecting parent to their fetuses. Further, the placenta conveys multiple impacts of the maternal environment to the growing fetus. The timing of placental development parallels that of the fetal cardiovascular system, and placental anomalies are implicated as a potential cause of congenital heart disease. For example, congenital heart disease is more common in pregnancies complicated by maternal preeclampsia, a condition characterized by placental dysfunction. Given the placenta's intermediary links to the maternal environment and fetal health outcomes, it is an emerging focus of evolutionary medicine, which seeks to understand how interactions between humans and the environment affect our biology and give rise to disease. The present review provides an overview of the evolutionary and developmental courses of the placenta as well as their implications on infant health.

Perinatal outcomes according to umbilical artery Doppler assessment among fetuses with congenital heart disease

PURPOSE

To evaluate a cohort of fetuses with congenital heart disease (CHD) who underwent serial umbilical artery (UA) Doppler surveillance and assess perinatal outcome according to UA Doppler assessment.

METHODS

A retrospective cohort study of singleton fetuses with CHD at a single academic center was performed between 2018 and 2020. Fetuses with a chromosomal abnormality or growth restriction were excluded. We compared fetuses with normal versus abnormal UA Doppler assessment at any time in pregnancy. Abnormal UA Doppler assessment was defined as decreased end diastolic flow, determined by an elevated systolic/diastolic ratio >95th percentile for gestational age, or absent/reversed end diastolic flow. Logistic regression assessed the odds of fetuses with CHD and abnormal UA Doppler assessment having a composite adverse perinatal (defined as fetal, neonatal, or infant death), adjusting for relevant covariates.

RESULTS

We identified a cohort of 171 fetuses with CHD that met inclusion criteria. Of these, 154 (90%) had normal UA Doppler assessment and 17 (10%) had abnormal UA Doppler assessment throughout pregnancy. Maternal characteristics did not differ between groups except for maternal race and history of preeclampsia. There was no statistically significant difference in primary outcome between groups [14% (21/154) of fetuses with normal UA Doppler assessment had an adverse perinatal outcome compared to 24% (4/17) of those with abnormal UA Doppler assessment, p = 0.28].

CONCLUSION

UA Doppler assessment is unlikely to predict adverse perinatal outcome in normally grown, euploid singleton fetuses with CHD.