Fetal tissue Doppler imaging in pregnancies complicated with preeclampsia with or without intrauterine growth restriction

Evaluation of Fetal Cardiac Functions in Preeclampsia: Does the Severity or Proteinuria Affect Fetal Cardiac Functions?

OBJECTIVE

To compare the fetal cardiac functions in preeclampsia and control group, and determine whether the severity or amount of proteinuria affects fetal cardiac functions.

METHODS

This prospective case-control study involves 48 pregnant women with preeclampsia and 48 healthy women. Pulsed wave Doppler, M-mode, and tissue Doppler imaging were used to measure the cardiac function between the 32 and 34 gestational weeks in each group. All Doppler indices and cardiac function parameters were also compared in subgroups with mild and severe preeclampsia and between subgroups with proteinuria >3 g/24 hours and <3 g/24 hours.

RESULTS

Decreased diastolic function (decreased E, A, E', and A' values in mitral/tricuspid valves and increased isovolumetric relaxation time) and decreased systolic functions (decreased mitral and tricuspid annular plane systolic excursion and S' value in mitral/tricuspid valves) were detected in the preeclampsia group. Decreased tricuspid E value in severe preeclampsia compared with mild preeclampsia was shown in the present study.

CONCLUSION

Preeclampsia may cause changes in systolic and diastolic functions in the fetal heart. Subclinical functional changes of these fetuses can be detected earlier and more sensitively with the help of tissue Doppler imaging. Biventricular diastolic functional changes are more prominent in preeclamptic cases with proteinuria >3 g/24 hours.

Short- and Long-Term Outcomes of Preeclampsia in Offspring: Review of the Literature

Preeclampsia is a multisystemic clinical syndrome characterized by the appearance of new-onset hypertension and proteinuria or hypertension and end organ dysfunction even without proteinuria after 20 weeks of pregnancy or postpartum. Residing at the severe end of the spectrum of the hypertensive disorders of pregnancy, preeclampsia occurs in 3 to 8% of pregnancies worldwide and is a major cause of maternal and perinatal morbidity and mortality, accounting for 8-10% of all preterm births. The mechanism whereby preeclampsia increases the risk of the neurodevelopmental, cardiovascular, and metabolic morbidity of the mother's offspring is not well known, but it is possible that the preeclamptic environment induces epigenetic changes that adversely affect developmental plasticity. These developmental changes are crucial for optimal fetal growth and survival but may lead to an increased risk of chronic morbidity in childhood and even later in life. The aim of this review is to summarize both the short- and long-term effects of preeclampsia on offspring based on the current literature.

Preeclampsia and Cardiovascular Risk for Offspring

There is growing evidence of long-term cardiovascular sequelae in children after in utero exposure to preeclampsia. Maternal hypertension and/or placental ischaemia during pregnancy increase the risk of hypertension, stroke, diabetes, and cardiovascular disease (CVD) in the offspring later in life. The mechanisms associated with CVD seem to be a combination of genetic, molecular, and environmental factors which can be defined as fetal and postnatal programming. The aim of this paper is to discuss the relationship between pregnancy complicated by preeclampsia and possibility of CVD in the offspring. Unfortunately, due to its multifactorial nature, a clear dependency mechanism between preeclampsia and CVD is difficult to establish.

Fetal cardiac function at 35-37 weeks' gestation in pregnancies that subsequently develop pre-eclampsia

OBJECTIVE

To compare fetal cardiac morphology and function between pregnancies that subsequently developed pre-eclampsia (PE) and those that remained normotensive.

METHODS

This was a prospective observational study in 1574 pregnancies at 35-37 weeks' gestation, including 76 that subsequently developed PE. We carried out comprehensive assessment of fetal cardiac morphology and function including novel imaging modalities, such as speckle-tracking echocardiography, and measured uterine artery pulsatility index, mean arterial pressure (MAP), serum placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and cerebroplacental ratio (CPR). The findings in the group that subsequently developed PE were compared to those in pregnancies that remained normotensive.

RESULTS

In fetuses of mothers who subsequently developed PE, compared to those from normotensive pregnancies, there was a more globular right ventricle, as shown by reduced right ventricular sphericity index, reduced right ventricular systolic contractility, as shown by reduced global longitudinal strain, and reduced left ventricular diastolic function, as shown by increased E/A ratio. On multivariable regression analysis, these indices demonstrated an association with PE, independent of maternal characteristics and fetal size. In pregnancies that subsequently developed PE, compared to those that remained normotensive, MAP, sFlt-1 and the incidence of low birth weight were higher, whereas serum PlGF, CPR and the interval between assessment and delivery were lower. These findings demonstrate that, in pregnancies that develop PE, there is evidence of impaired placentation, reflected in low PlGF and reduced birth weight, placental ischemia, evidenced by increased sFlt-1 which becomes apparent in the interval of 2-4 weeks preceding the clinical onset of PE, and consequent fetal hypoxia-induced redistribution in the fetal circulation, reflected in the low CPR.

CONCLUSION

Although the etiology of the observed fetal cardiac changes in pregnancies that subsequently develop PE remains unclear, it is possible that the reduction in right-heart systolic function is the consequence of high afterload due to increased placental resistance, whilst the early left ventricular diastolic changes could be due to fetal hypoxia-induced redistribution in the fetal circulation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Global longitudinal reference ranges for fetal myocardial deformation in the second half of pregnancy

PURPOSE

To construct longitudinal fetal reference ranges for global longitudinal myocardial deformation (strain and strain rate) of the left and right ventricles in the second half of pregnancy.

METHODS

A prospective, observational, longitudinal study of 120 women with uncomplicated singleton pregnancies. The participants underwent ultrasonographic scans every 4 weeks from enrolment (18-28 weeks) until delivery. Strain and strain rate were measured at each examination using velocity vector imaging. Changes in strain and strain rate as functions of gestational age (GA) were modeled using Bayesian mixed effects models.

RESULTS

A total of 406 assessments of global longitudinal strain and strain rate were performed for 120 women. Global longitudinal strain and strain rate decreased with increasing GA in the left ventricle. There was, however, no change in strain measurements of the right ventricle over the same gestational time frame. Posterior predictive distributions were used to derive reference centiles for each week of GA.

CONCLUSION

Assessment of myocardial deformation of the fetal heart is easily performed and may be useful for quantitative assessment of heart function, particularly in fetuses at risk of cardiac dysfunction.

The effects of pre-pregnancy obesity on fetal cardiac functions

Obesity is a substantial public health problem with a rapidly increasing prevalence in numerous industrialized nations. The objective of this study was to evaluate the effects of maternal pre-pregnancy obesity on fetal cardiac functions. We studied 55 fetuses of obese mothers and 44 fetuses of healthy mothers at 26-38 weeks of gestation. Cardiac functions were evaluated by M-mode, pulsed-wave, and tissue Doppler echocardiography. The two groups were similar in terms of maternal age, gravidity, parity, gestational age, estimated birth weight, serum lipids, and systolic-diastolic blood pressure. Fetal heart rate, diameters of the aortic and pulmonary valve annulus, aortic and pulmonary peak systolic velocities, ventricular systolic function, and cardiothoracic ratio were similar in the two groups. Pulsed-wave Doppler-derived E/A ratios in the mitral and tricuspid valves were similar in the two groups. The deceleration time of early mitral inflow was prolonged in the fetuses of the obese mothers. In the interventricular septum, left ventricle posterior wall, and right ventricle free wall, the E a and A a were higher, and E a/A a ratios were significantly lower in the study group than in the control group. The E/E a ratio was higher in the obese group than in the control group. The isovolumic relaxation time and the right and left ventricle myocardial performance indices were higher in the fetuses of the obese mothers than in the fetuses of the healthy mothers. We believe that maternal obesity has an important influence on fetal cardiac diastolic functions.

Assessment of fetal cardiac function in mild preeclampsia

This study investigated cardiac function in 65 fetuses of mildly preeclamptic mothers and 55 fetuses of healthy mothers at 26-40 weeks of gestation. Fetuses with intrauterine growth restriction were excluded. Cardiac functions were evaluated by M-mode, pulsed-wave, and tissue Doppler echocardiography. The two groups were similar in terms of maternal age, gravidity, parity, and gestational age. Peak systolic aortic and pulmonary artery velocities were significantly lower in the fetuses of the preeclamptic mothers than in the fetuses of the healthy mothers. The two groups did not differ significantly in terms of shortening fraction or with regard to mitral or tricuspid annular plane systolic excursion. Pulsed-wave Doppler-derived E/A ratios in the mitral and tricuspid valves were similar in the two groups. The deceleration time of early mitral inflow was prolonged in the fetuses of the preeclamptic mothers. The Ea, Aa, and Ea/Aa ratios in the interventricular septum, left ventricle posterior wall, and right ventricle free wall were lower in the preeclampsia group than in the control group. The E/Ea ratio was higher in the preeclampsia group than in the control group. The isovolumic relaxation time and the right and left myocardial performance indices were higher in the fetuses of the preeclamptic mothers than in the fetuses of the healthy mothers. An increased ductus venosus pulsatility index (PI) and a decreased middle cerebral artery (MCA) PI were found in the fetuses of the preeclamptic mothers. All the fetuses were asymptomatic. The results suggest that the increase in fetal cardiac afterload in mild preeclampsia may have caused early subclinical changes in fetal systolic and diastolic cardiac function. In addition, the decrease in MCA-PI may have been caused by redistribution of fetal cardiac output in favor of the left ventricle, secondary to increased placental vascular resistance.