Spectral Doppler, tissue Doppler, and speckle-tracking echocardiography for the evaluation of fetal cardiac function: an update

Fetal cardiac function in pregnancy affected by congenital heart disease: protocol for a multicentre prospective cohort study

BACKGROUND

Congenital heart disease (CHD) is the most common fetal malformation, and it can result first in cardiac remodeling and dysfunction and later in cardiac failure and hydrops. A limited number of studies have evaluated cardiac function in fetuses affected by CHD. Functional parameters could potentially identify fetuses at risk of cardiac failure before its development. However, these techniques have not translated from research to clinical settings, due to a lack of standardization and poor repeatability. We seek to evaluate whether application of automated techniques to a cohort with fetal pathology could overcome these factors.

METHODS

A multicenter cohort study will be carried out in eight teaching hospitals across Europe, Australia, and Middle East. Based on a previous observed standard deviation, a total sample of 381 pregnancies is required to achieve 80% power to detect a difference of 0.03 in mean myocardial performance index (MPI) with a two-sided type I error rate of 5%. After adjustments allowing for patient exclusions or incomplete datasets, a total of 330 healthy singleton pregnancies and 165 diagnosed with CHD will be recruited. Two fetal cardiac function evaluations at 19 + 6-28 + 6 and 32 + 6-36 + 6 weeks will be offered assessing automated pulsed wave doppler (PWD) MPI, spatio-temporal image correlation (STIC) annular and septal plane excursion (TAPSE, MAPSE and SAPSE), alongside cardiac morphometric and Doppler evaluations of flow across the valves. A secondary nested case-control study will evaluate fetuses with hydrops compared to those without. Differences in functional parameters between cases and controls and over time will be assessed using generalized linear mixed models. Logistic regression will estimate the association between cardiac parameters and hydrops' incidence.

DISCUSSION

This study will provide evidence as to whether automated functional parameters could be significantly different in pregnancy affected by CHD versus healthy pregnancies. The primary objective is to compare automated PWD-MPI and STIC TAPSE, MAPSE and SAPSE in fetuses affected by CHD versus healthy. The secondary objective is to estimate whether these automated parameters could improve the predictive value of the classical cardiovascular profile score in case of hydrops.

TRIAL REGISTRATION

The study protocol has been registered in the ClinicalTrials.gov Protocol Registration System, identification number NCT05698277.

Speckle Tracking Echocardiography in Twin Pregnancies and the Role of Global Longitudinal Strain and Peak Systolic Strain: A Systematic Review and Meta-Analysis

INTRODUCTION

Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality. Pregnancy complications related to twins, such as fetal growth restriction, and twin-to-twin transfusion syndrome (TTTS), are associated with hemodynamic changes in the fetal heart. Two-dimensional speckle tracking echocardiography (2D STE) is a tool to evaluate fetal cardiac function. This paper aims to review the literature regarding global longitudinal strain (rate) and peak systolic strain (rate) assessed with 2D STE in twin pregnancies. Feasibility, frame rate, and angle of the fetal heart at the time of measurement were selected as secondary outcomes.

METHODS

The databases Medline, Embase, Scopus, and Web of Science were searched.

RESULTS

Seven articles met the inclusion criteria and selected all monochorionic diamniotic (MCDA) twins with TTTS as the study population. The global longitudinal strain in the right and left ventricle and the peak systolic strain in the right ventricle of the recipient MCDA twin are significantly decreased compared to the donor MCDA twin. 2D STE assessment was shown feasible and reproducible in MCDA pregnancies. Large heterogeneity in technical characteristics between the articles induces inconsistent results.

CONCLUSION

Although feasible, the knowledge of 2D STE is very limited in twin pregnancy. Prospective studies are needed to evaluate the 2D STE assessment in uncomplicated twin pregnancies considering its possible additive value in the diagnostics of pregnancy-related pathologies.

Left Ventricular Vortex Characteristics in Fetuses With Coarctation of the Aorta by Blood Speckle-Tracking Echocardiography

OBJECTIVES

The aims of this study were to assess the vortex characteristics of left ventricle (LV) in fetuses with coarctation of the aorta (CoA) using high-frame rate ultrasound with blood speckle-tracking (BST) and explore its relationships with cardiac function and morphology parameters.

METHODS

Thirty fetuses with CoA and 30 gestational-age matched normal fetuses were included in this cross-sectional study. The area, length, width, and position of the vortex in the LV were recorded and quantitatively analyzed by BST echocardiography. The associations of vortex properties with ventricular function and morphology were also determined.

RESULTS

Based on BST imaging, the LV vortex can be observed in 93% of the fetuses. The fetuses with CoA exhibited significantly larger and wider vortex than the controls (P < .05). Linear regression analysis indicated that vortex area was positively related to sphericity index of LV as well as isovolumic relaxation time (r = .52, P = .003 and r = .42, P = .021). There was a negative correlation between vortex area and mitral valve size (r = -.443, P = .014). No significant association was found between vortex area and myocardial performance index and aortic isthmus size.

CONCLUSIONS

It is feasible to quantitatively evaluate the left ventricular vortex in fetuses by BST. The fetuses with CoA exhibited greater vortex area and width, and the altered vortex property is associated with geometry of LV. This will facilitate our comprehension of the unique flow patterns and early cardiac remodeling in fetuses with CoA.

Impact of overweight and obesity in the fetal cardiac function parameters in the second and third trimesters of pregnancy

OBJECTIVE

To assess the impact of overweight and obesity in the second and third trimesters of pregnancy on fetal cardiac function parameters.

METHODS

We performed a prospective cohort study of 374 singleton pregnant women between 20w0d and 36w6d divided into three groups: 154 controls (body mass index - BMI < 25 kg/m2), 140 overweight (BMI 25-30 kg/m2) and 80 obese (BMI ≥ 30 kg/m2). Fetal left ventricular (LV) modified myocardial performance index (Mod-MPI) was calculated according to the following formula: (isovolumetric contraction time + isovolumetric relaxation time)/ejection time. Spectral tissue Doppler was used to determine LV and right ventricular (RV) myocardial performance index (MPI'), peak myocardial velocity during systole (S'), early diastole (E'), and late diastole (A').

RESULTS

We found significant differences between the groups in maternal age (p < 0.001), maternal weight (p < 0.001), BMI (p < 0.001), number of pregnancies (p < 0.001), parity (p < 0.001), gestational age (p = 0.013), and estimated fetal weight (p = 0.003). Overweight pregnant women had higher LV Mod-MPI (0.046 versus 0.044 seconds, p = 0.009) and LV MPI' (0.50 versus 0.47 seconds, p < 0.001) than the control group. Obese pregnant women had higher RV E' than control (6.82 versus 6.33 cm/sec, p = 0.008) and overweight (6.82 versus 6.46 cm/sec, p = 0.047) groups. There were no differences in 5-min APGAR score < 7, neonatal intensive care unit admission, hypoglycemia and hyperglobulinemia between the groups.

CONCLUSIONS

We observed fetal myocardial dysfunction in overweight and obese pregnant women with higher LV Mod-MPI, LV MPI' and RV E' compared to fetuses from normal weight pregnant women.

Characterization of the normal fetal circulatory system of the ductus venosus using sound complexity parameters

The aim of this study was to characterize the normality of the fetal circulatory system through the time between ventricular systoles of the ductus venosus in the three gestational trimesters in healthy fetuses using nonlinear methods of the complexity of the signal. A prospective cohort study was conducted at the Instituto de Medicina Integral Prof. Fernando Figueira (IMIP) from December 2019 to May 2020. Pregnant women between 11 and 14 weeks, with intrauterine pregnancy and healthy fetus were included. Patients with multiple gestation, positive screening for congenital malformation, including heart disease, and under 18 years of age were excluded. Doppler velocimetry ultrasonography of the ductus venosus was performed between the 11th and 14th weeks, 20th and 24th weeks, and 28th and 32nd weeks of gestation, and then the sound signal was extracted and segmented from the videos. To compare the means between the gestational trimesters of the approximate entropy (ApEn) and Lempel-Ziv complexity (CLZ) of the time between ventricular systoles, the Friedman test was used, with a significance level of 5%. No statistically significant difference was found between the 1st, 2nd, and 3rd trimesters regarding the mean ApEn (P=0.281) and CLZ (P=0.595) of the time between ventricular systoles of the ductus venosus. Ductus venosus systolic time was not sensitive to differentiate fetal cardiovascular dynamics between gestational trimesters. This study pioneered the characterization of cardiovascular normality by nonlinear parameters of the fetal ductus venosus in all three trimesters.

Prenatal Diagnosis of Fetal Heart Failure

Fetal heart failure (FHF) is a condition of inability of the fetal heart to deliver adequate blood flow for tissue perfusion in various organs, especially the brain, heart, liver and kidneys. FHF is associated with inadequate cardiac output, which is commonly encountered as the final outcome of several disorders and may lead to intrauterine fetal death or severe morbidity. Fetal echocardiography plays an important role in diagnosis of FHF as well as of the underlying causes. The main findings supporting the diagnosis of FHF include various signs of cardiac dysfunction, such as cardiomegaly, poor contractility, low cardiac output, increased central venous pressures, hydropic signs, and the findings of specific underlying disorders. This review will present a summary of the pathophysiology of fetal cardiac failure and practical points in fetal echocardiography for diagnosis of FHF, focusing on essential diagnostic techniques used in daily practice for evaluation of fetal cardiac function, such as myocardial performance index, arterial and systemic venous Doppler waveforms, shortening fraction, and cardiovascular profile score (CVPs), a combination of five echocardiographic markers indicative of fetal cardiovascular health. The common causes of FHF are reviewed and updated in detail, including fetal dysrhythmia, fetal anemia (e.g., alpha-thalassemia, parvovirus B19 infection, and twin anemia-polycythemia sequence), non-anemic volume load (e.g., twin-to-twin transfusion, arteriovenous malformations, and sacrococcygeal teratoma, etc.), increased afterload (intrauterine growth restriction and outflow tract obstruction, such as critical aortic stenosis), intrinsic myocardial disease (cardiomyopathies), congenital heart defects (Ebstein anomaly, hypoplastic heart, pulmonary stenosis with intact interventricular septum, etc.) and external cardiac compression. Understanding the pathophysiology and clinical courses of various etiologies of FHF can help physicians make prenatal diagnoses and serve as a guide for counseling, surveillance and management.

Alterations in Fetal Doppler Parameters Before and Twenty-Four Hours After Radiofrequency Ablation for Twin Reversed Arterial Perfusion Sequence

Objective

To evaluate alterations in the fetal Doppler parameters of pump fetuses before and 24 h after radiofrequency ablation surgery for twin reversed arterial perfusion sequence (TRAPs).

Methods

This is a retrospective study of 28 pump fetuses in TRAPs and 28 normal control twins between 2016 and 2021. The fetal Doppler parameters, including the umbilical artery pulsatility index (UA-PI), middle cerebral artery peak systolic velocity (MCA-PSV), middle cerebral artery pulsatility index (MCA-PI), and cerebroplacental ratio (CPR), of the controls, and pump fetuses before and 24 h after surgery were compared.

Results

An increasing trend and a further increase in the MCA-PSV, MCA-PI, MCA-PSV Z score, and MCA-PI Z score after surgery were observed in pump fetuses with gestational age (GA) ≥20 weeks; however, such changes were not observed in those with a GA of <20 weeks. The UA-PI and CPR before and after surgery were not different between control and pump fetuses, whether the GA was ≥20 or <20 weeks.

Conclusion

In the middle second trimester, the pump fetus might suffer from high cardiac output rather than hypoxemia before surgery and congestive heart failure, or hemodilutional anemia after surgery. This may provide some theoretical evidence in favor of early intervention, rather than waiting for a more advanced GA, to avoid unnecessary hemodynamic alterations.