The importance of venous Doppler velocimetry for evaluation of intrauterine growth restriction

The abnormal umbilical venous-arterial index in the second half of pregnancy is associated with fetal outcome: A retrospective cross-sectional study

Objective

This study aims to observe the changes of the umbilical venous-arterial index (VAI) and investigate its predictive power for fetal outcome during the second half of pregnancy.

Methods

Fetuses with gestational age (GA) at 24-39 weeks were collected. According to the outcome score, neonates with outcome scores of 0, 1, or 2 were assigned to the control group, whereas those with scores of 3-12 were assigned to the compromised group. VAI was calculated as the ratio of normalized umbilical vein blood flow volume and umbilical artery pulsatility index. Regression analysis was performed to obtain the best-fitting curves between VAI and GA in the controls. Doppler parameters and perinatal outcomes were compared in both groups. Receiver operating characteristic analysis was used to assess the diagnostic performance of the VAI.

Results

A total of 833 (95%) fetuses had Doppler parameters and pregnancy outcomes documented. Compared with the controls, the VAI was significantly lower in the compromised group (83.2 vs. 184.8 ml/min/kg, p < 0.001). The sensitivity and specificity of VAI to predict compromised neonates were 95.15% (95% Cl, 89.14 to 97.91%) and 99.04% (95% CI: 98.03 to 99.53%), respectively at a cutoff value of 120 ml/min/kg.

Conclusions

VAI presents better diagnostic performance than umbilical vein blood flow volume and umbilical artery pulsatility index. A cutoff value of 120 ml/min/kg might be used as the warning value for predicting the fetal outcome.

Association between Abnormal Antenatal Doppler Characteristics and Gastrointestinal Outcomes in Preterm Infants

Antenatal Doppler disturbances are associated with fetal hypoxia and may induce a brain-sparing vascular redistribution at the expense of splanchnic circulation, possibly predisposing to gut complications. We aimed to compare several gastrointestinal outcomes among very-low-birthweight (VLBW) preterm infants with different antenatal Doppler features. VLBW infants born between 2010-2022 were retrospectively included and stratified into the following clusters based on antenatal Doppler characteristics: normal Doppler (controls); absent or reversed end-diastolic flow in the umbilical artery (UA-AREDF) alone or also in the ductus venosus (UA+DV-AREDF); and abnormal Doppler with or without brain-sparing redistribution. The following outcomes were evaluated: time to reach full enteral feeds (FEF), feeding intolerance (FI), necrotizing enterocolitis (NEC), and spontaneous intestinal perforation (SIP). Overall, 570 infants were included. Infants born following UA+DV-AREDF had significantly higher FI, NEC, and SIP rates and achieved FEF later compared to controls. Increased FI prevalence and a longer time to FEF compared to controls were also observed among UA-AREDF infants and in the presence of brain-sparing redistribution, which also increased NEC rates. Antenatal Doppler abnormalities exacerbate the gastrointestinal risks of preterm infants. Detailed knowledge of Doppler features can aid in identifying those at highest risk of intestinal complications who may benefit from tailored enteral feeding management.

Use of intravoxel incoherent motion MRI to assess placental perfusion in normal and Fetal Growth Restricted pregnancies on their third trimester

INTRODUCTION

Intravoxel Incoherent Motion (IVIM) MRI is a non-invasive, in vivo techniques which can assess placental perfusion quantitatively, and be useful for evaluating placental microcirculation. Our primary aim was to investigate whether fetal growth restriction (FGR) pregnancies have different placental perfusion and diffusion compared with normal pregnancies using IVIM. A secondary aim was to investigate correlations between placental IVIM parameters and gestational age in normal pregnancy.

METHODS

This study population included 17 FGR pregnancies and 36 normal pregnancies between 28 + 3 to 38 + 0 weeks. All women underwent a MRI examination including an IVIM sequence with 9 b-values on a 3.0 T MRI system. The standard diffusion coefficeint (D), pseudodiffusion (D*) and perfusion fraction (f) were calculated.

RESULTS

Placental f was significantly lower in the FGR group than that in the normal group (33.96 ± 2.62(%) vs 38.48 ± 5.31(%), p = 0.002). Placental D and D* in two groups showed no statistical significance (P > 0.05). Placental f moderately increased with increasing gestational age in normal pregnancies (r = 0.411, p = 0.013), and there existed a negative correlation between D values and gestational age (r = -0.390, p = 0.019).

DISCUSSION

The f values are able to distinguish FGR from normal pregnancies. It can be uses as a feasible index to evaluate placenta perfusion. Gestational age-associated changes in placental IVIM parameters likely reveal trajectories of microvascular perfusion fraction and diffusion characteristics in the normal developing placenta.

Cerebroplacental ratio and aortic isthmus Doppler in early fetal growth restriction

PURPOSE

To assess the utility of cerebroplacental ratio (CPR) and fetal aortic isthmus (AoI) Doppler in the prediction of perinatal outcome in early fetal growth restriction (FGR).

METHODS

A prospective observational cohort study of 70 early FGR cases was conducted through serial Doppler examinations and findings of the last examination were correlated with perinatal outcome. Doppler blood flow measurements of AoI included end diastolic velocity (EDV), peak systolic velocity (PSV), pulsatility index (PI), resistance index (RI), and isthmic flow index (IFI).

RESULTS

Significant association of CPR and all Doppler indices of AoI with the overall adverse perinatal outcome was seen. The sensitivity of CPR was moderate (63.64%) but higher than most AoI indices. Most AoI Doppler indices (PI, RI, IFI) had higher specificities (100%). AoI PSV and EDV had higher sensitivities than CPR for the prediction of overall adverse perinatal outcome, with AoI PSV having the highest sensitivity (100%).

CONCLUSION

CPR shows significant association and moderate sensitivity for prediction of overall adverse perinatal outcome in early FGR; hence recommended in all cases of early FGR. AoI Doppler also appears to have a role in assessment and decision making in FGR in view of high sensitivity and high specificity of AoI indices in the prediction of perinatal outcome. However, larger studies are required to confirm its utility in the management of early FGR.

Placenta microstructure and microcirculation imaging with diffusion MRI

PURPOSE

To assess which microstructural models best explain the diffusion-weighted MRI signal in the human placenta.

METHODS

The placentas of nine healthy pregnant subjects were scanned with a multishell, multidirectional diffusion protocol at 3T. A range of multicompartment biophysical models were fit to the data, and ranked using the Bayesian information criterion.

RESULTS

Anisotropic extensions to the intravoxel incoherent motion model, which consider the effect of coherent orientation in both microvascular structure and tissue microstructure, consistently had the lowest Bayesian information criterion values. Model parameter maps and model selection results were consistent with the physiology of the placenta and surrounding tissue.

CONCLUSION

Anisotropic intravoxel incoherent motion models explain the placental diffusion signal better than apparent diffusion coefficient, intravoxel incoherent motion, and diffusion tensor models, in information theoretic terms, when using this protocol. Future work will aim to determine if model-derived parameters are sensitive to placental pathologies associated with disorders, such as fetal growth restriction and early-onset pre-eclampsia. Magn Reson Med 80:756-766, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Use of Doppler velocimetry in diagnosis and prognosis of intrauterine growth restriction (IUGR): A Review

Intrauterine growth restriction (IUGR) is a condition which has been difficult to assess at an early stage, resulting in the delivery of children who have poor genetic growth potential. Currently, IUGR classification is based upon the system of ultrasound biometry. Doppler velocimetry allows the measurement of hemodynamic flow of major fetal vessels, comparing the flow indices and patterns of normal and IUGR cases. In this review, the effectiveness of Doppler velocimetry in assessing blood flow in major vessels including the umbilical artery, ductus venosus, and middle cerebral artery was studied for both diagnostic and prognostic screening of IUGR. The umbilical artery is the most frequently studied vessel in Doppler velocimetry due to its accessibility and the strength of its associations with fetal outcomes. Abnormalities in the ductus venosus waveform can be indicative of increased resistance in the right atrium due to placental abnormalities. The middle cerebral artery is the most studied fetal cerebral artery and can detect cerebral blood flow and direction, which is why these three vessels were selected to be examined in this context. A potential mathematical model could be developed to incorporate these Doppler measurements which are indicative of IUGR, in order to reduce perinatal mortality. The purpose of the proposed algorithm is to integrate Doppler velocimetry with biophysical profiling in order to determine the optimal timing of delivery, thus reducing the risks of adverse perinatal outcomes.

Growth restriction: identifying fetuses at risk

PURPOSE

Examine risks of intrauterine growth restriction (IUGR) and composite perinatal outcomes with estimated fetal weights (EFW) 10-20th%, and compare outcomes using umbilical artery Doppler (UAD).

MATERIALS AND METHODS

Retrospective, cohort evaluating ultrasound (US) EFW 10-20th%, between 2002 and 2012. Cases were identified with EFW % 10-20. Controls, EFW >20th% were obtained for each case, matched by gestational age, and US date. Unadjusted and adjusted logistic regression was used for outcomes.

RESULTS

Seven hundred and sixty-seven cases met criteria with matched controls. Fetuses having EFW 10-20th% (GA 33.6 ± 3.7 weeks) had increased IUGR on follow up ultrasound (OR 26.5[10.2-68.7], p < .01), small for gestational age (SGA) (OR 9.2 [6.9-12.3], p < .01), neonatal intensive care unit (NICU) admissions (OR 2.4 [1.6-3.6], p < .01), and composite perinatal morbidity (OR 7.8 [6.0-10.1], p < .01) on adjusted analyses. Abnormal UAD in cases had greater rates of 5 min Apgar <7, NICU admission and composite morbidity (p < .05).

CONCLUSIONS

Pregnancies with EFW 10-20th% at the time of initial US are at increased risk for developing IUGR and being SGA at birth, with more NICU admissions and composite perinatal outcomes; abnormal UAD evaluation in cases conveyed further increase in outcomes.

Clinical application of fetal left modified myocardial performance index in the evaluation of fetal growth restriction

OBJECTIVE

This study aims to evaluate cardiac function in fetuses with intrauterine growth restriction (IUGR) compared with healthy fetuses, using the left modified myocardial performance index (MPI) and the association between MPI and perinatal outcome.

METHODS

Pregnant women between 34 and 39 weeks of gestation, who met the criteria for IUGR and were scheduled for delivery at an Egyptian tertiary medical center, were prospectively enrolled in the study. Women in the same gestational-age group with uncomplicated pregnancies were included as a control group. MPI was measured in all fetuses. The IUGR group was analyzed based on normal and abnormal umbilical artery (UA) Doppler. Perinatal outcomes were recorded.

RESULTS

The mean left MPI was significantly higher in IUGR fetuses with abnormal UA Doppler (mean 0.58±SD 0.093) compared with healthy fetuses (mean 0.45±SD 0.070) (P<0.001). IUGR fetuses with abnormal left MPI showed significantly worse perinatal outcome and increased morbidity compared with the control group. IUGR fetuses with abnormal left MPI also showed significantly worse perinatal outcome compared with IUGR fetuses with normal MPI (whether the UA Doppler was normal or abnormal). The fetal MPI was associated with the severity of fetal compromise in IUGR fetuses based on the perinatal outcome.

CONCLUSION

MPI is a potentially useful tool in evaluating fetuses with suspected IUGR, which is crucial in classifying IUGR pregnancies into critical and non-critical cases and in predicting neonatal outcome.

Placental contribution to nutritional programming of health and diseases: epigenetics and sexual dimorphism

The recent and rapid worldwide increase in non-communicable diseases challenges the assumption that genetic factors are the primary contributors to such diseases. A new concept of the ‘developmental origins of health and disease’ (DOHaD) is at stake and therefore requires a paradigm shift. Maternal obesity and malnutrition predispose offspring to develop metabolic syndrome, a vicious cycle leading to transmission to subsequent generation(s), with differences in response and susceptibility according to the sex of the individual. The placenta is a programming agent of adult health and disease. Adaptations of placental phenotype in response to maternal diet and metabolic status alter fetal nutrient supply. This implies important epigenetic changes that are, however, still poorly documented in DOHaD studies, particularly concerning overnutrition. The aim of this review is to discuss the emerging knowledge on the relationships between the effect of maternal nutrition or metabolic status on placental function and the risk of diseases later in life, with a specific focus on epigenetic mechanisms and sexual dimorphism. Explaining the sex-specific causal variables and how males versus females respond and adapt to environmental perturbations should help physicians and patients to anticipate disease susceptibility.

IUGR management: new perspectives

AIM OF THE STUDY

Analyzing velocimetric (umbilical artery, UA; ductus venosus, DV; middle cerebral artery, MCA) and computerized cardiotocographic (cCTG) (fetal heart rate, FHR; short term variability, STV; approximate entropy, ApEn) parameters in intrauterine growth restriction, IUGR, in order to detect early signs of fetal compromise. POPULATION STUDY: 375 pregnant women assisted from the 28th week of amenorrhea to delivery and monitored through cCTG and Doppler ultrasound investigation. The patients were divided into three groups according to the age of gestation at the time of delivery, before the 34th week, from 34th to 37th week, and after the 37th week. Data were analyzed in relation to the days before delivery and according to the physiology or pathology of velocimetry. Statistical analysis was performed through the t-test, chi-square test, and Pearson correlation test (P < 0.05). Our results evidenced an earlier alteration of UA, DV, and MCA. The analysis between cCTG and velocimetric parameters (the last distinguished into physiological and pathological values) suggests a possible relation between cCTG alterations and Doppler ones. The present study emphasizes the need for an antenatal testing in IUGR fetuses using multiple surveillance modalities to enhance prediction of neonatal outcome.

Reference values for fetal tissue velocity imaging and a new approach to evaluate fetal myocardial function

OBJECTIVES

Myocardial function can be evaluated using color-coded tissue velocity imaging (TVI) to analyze the longitudinal myocardial velocity profile, and by expressing the motion of the atrioventricular plane during a cardiac cycle as coordinated events in the cardiac state diagram (CSD). The objective of this study was to establish gestational age specific reference values for fetal TVI measurements and to introduce the CSD as a potential aid in fetal myocardial evaluation.

METHODS

TVI recordings from 125 healthy fetuses, at 18 to 42 weeks of gestation, were performed with the transducer perpendicular to the apex to provide a four-chamber view. The myocardial velocity data was extracted from the basal segment of septum as well as the left and right ventricular free wall for subsequent offline analysis.

RESULTS

During a cardiac cycle the longitudinal peak velocities of septum increased with gestational age, as did the peak velocities of the left and right ventricular free wall, except for the peak velocity of post ejection. The duration of rapid filling and atrial contraction increased during pregnancy while the duration of post ejection decreased. The duration of pre ejection and ventricular ejection did not change significantly with gestational age.

CONCLUSION

Evaluating fetal systolic and diastolic performance using TVI together with CSD could contribute to increase the knowledge and understanding of fetal myocardial function and dysfunction. The pre and post ejection phases are the variables most likely to indicate fetuses with abnormal myocardial function.

Fetal blood flow velocimetry by phase-contrast MRI using a new triggering method and comparison with Doppler ultrasound in a sheep model: a pilot study

OBJECT

We present the first study demonstrating the feasibility of antenatal blood flow velocimetry performing ECG triggered phase-contrast (PC)-MRI in the fetal aorta by using a newly developed Doppler ultrasound trigger.

MATERIALS AND METHODS

Five pregnant sheep carrying singleton fetuses (gestational age 121 days) were anesthetized to undergo fetal 2D PC-MRI in the fetal descending aorta (1.5 T) using a newly developed MR-compatible Doppler ultrasound trigger for fetal cardiac triggering. Inter-operator variability was assessed for PC-MR measurements and reproducibility was tested by repeated scans in one fetus. Inter-modality comparison was performed by Doppler ultrasound velocimetry.

RESULTS

Fetal cardiac triggering was possible in all examinations. PC-MR velocimetry revealed a mean inter-operator variability of 3 ± 5%. Average peak systolic flow velocities of 62.5 ± 4.4 cm/s were in good agreement with Doppler ultrasound measurements of 62.0 ± 9.2 cm/s (p (Lord's U test) ≫ 0.05).

CONCLUSION

Fetal PC-MR velocimetry was successfully performed using the newly developed MR-compatible Doppler ultrasound trigger for intrauterine fetal cardiac triggering, demonstrating high inter-operator and inter-modality agreement. This new method has the high potential for alternative assessment of hemodynamic decompensation of the fetal circulation.

Umbilical venous blood flow and its measurement in the human fetus

In this review, we evaluate the published methodologies to describe a noninvasive technique for the quantitative assessment of umbilical venous blood flow in the human fetus. We identify a number of variations in the reported methodologies and address some of the common errors associated with Doppler assessment of umbilical venous flow volume. The potential role of umbilical venous flow volumetry in the management of intrauterine growth restriction is briefly evaluated including its utility and reliability in everyday clinical practice.

Abnormal Fetal Umbilical Cord Doppler? What Should I Do Next? A Case Study Demonstrating Corroboration of Umbilical Cord Doppler and Middle Cerebral Doppler

For the fetus at risk for intrauterine growth restriction (IUGR), umbilical cord Doppler provides the clinician valuable information about fetal circulation. When the cord Doppler is abnormal, spectral analysis of the middle cerebral artery (MCA) gives additional information about perfusion to the fetal brain. This case report describes a 31-week gestational age fetus referred for a biophysical profile and umbilical cord Doppler because of an abnormal nonstress test.

Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study

Background

Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI).

Methods

TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201–273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis.

Results

Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E’/A’ ratio also increased with gestational age, while a longitudinal shortening was demonstrated.

Conclusions

Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal- and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.