Sensitive detection of hemodynamic changes after fetoscopic laser photocoagulation by assessing intraventricular pressure difference in fetuses with twin-to-twin transfusion syndrome

OBJECTIVES

To assess the hemodynamics of twin-to-twin transfusion syndrome (TTTS), we measured the intraventricular pressure difference (IVPD), a sensitive marker of myocardial diastolic function, using fetal echocardiography.

METHODS

We included 28 monochorionic diamniotic (MD) twins diagnosed with TTTS who underwent fetoscopic laser photocoagulation (FLP) between 2018 and 2022. Color M-mode Doppler images of both cardiac ventricles were obtained before and after FLP. According to this evaluation, the IVPDs were divided into three groups; those with total, basal, and mid-apical IVPD.

RESULTS

Of the 28 twins, 21 were available for analysis (including eight, eight, three, and two cases in stages Quintero Ⅰ, Ⅱ, Ⅲd, and Ⅲr, respectively). Comparing the pre and postFLP results, significant increases in total and mid-apical IVPD in the left ventricle (LV) of recipient twins were noted (total and mid-apical IVPD: p=0.026 and 0.013, respectively). In the LV of the donor twins, all IVPDs were significantly increased after FLP (total, basal, and mid-apical IVPD: p=0.003, 0.001, and 0.022, respectively). In addition, comparisons between the donor and recipient groups did not show significant differences in either ventricle before FLP.

CONCLUSIONS

IVPD detected subtle hemodynamics changes, such as volume overload and diastolic dysfunction in TTTS before and after FLP. Therefore, IVPD may be a useful marker for monitoring myocardial diastolic function in TTTS.

Reference Ranges and Development Patterns of Fetal Myocardial Function Using Speckle Tracking Echocardiography in Healthy Fetuses at 17 to 24 Weeks of Gestation

OBJECTIVE

The purposes of the study were to develop reference ranges and maturation patterns of fetal cardiac function parameters measured by speckle tracking echocardiography (STE) using multiple biometric variables at 17 to 24 weeks' gestation among Thai fetuses and to compare with other previous reports.

STUDY DESIGN

The four-chamber view of the fetal heart in 79 healthy fetuses was suitably analyzed by STE to establish the best-fit regression model. The 95% reference intervals and Z-score equations of fetal cardiac function parameters were computed.

RESULTS

The fractional area change of both ventricles, left ventricular (LV) end-diastolic and end-systolic volumes, LV stroke volume, LV cardiac output (CO), and LV CO per kilogram were all increased according to gestational age (GA) and five fetal biometric measurements. However, the global longitudinal strain, basal-apical length fractional shortening (BAL-FS), BAL annular free wall and septal wall FS, BAL free wall and septal wall annular plane systolic excursions, 24-segment transverse width FS, as well as LV ejection fraction were all independent of GA or other somatic characteristics. There were varying development patterns between fetal right and left ventricles of these cardiac function indices across the gestation period.

CONCLUSION

Our study created Z-score and corresponding centile calculators, 5th and 95th centile reference tables, and corresponding graphs and determined the normal evolution across gestation using multiple somatic growth and age variables between 17 and 24 gestational weeks. These nomograms serve as an essential prerequisite for quantitatively evaluating fetal cardiac contractility and allow for precisely detecting early changes in the fetal heart function.

KEY POINTS

· Most fetal cardiac function measurements were correlated with all the independent variables.. · Fetal ventricular function parameters have their own characteristic maturation changes.. · Racial variability may not occupy an important place for fetal myocardial function during these GA..

Cardiac adaptation and malformation in twin-twin transfusion syndrome and selective fetal growth restriction: A systematic review

OBJECTIVES

This systematic review explores cardiac adaptation in monochorionic (MC) twins with twin-twin transfusion syndrome (TTTS) or selective fetal growth restriction (sFGR) and assesses the risk of congenital heart defects (CHDs).

METHODS

Adhering to PRISMA guidelines, 63 studies were reviewed (49 on cardiac adaptation, 13 on CHD, one on both). A narrative synthesis of cardiac adaptation patterns was performed. Additionally, a meta-analysis compared the livebirth prevalence of CHD in TTTS and sFGR against uncomplicated MC twins.

RESULTS

In TTTS recipients, cardiac function may be impaired for diastolic, systolic, as well as global functions, while in donors, cardiac function is generally preserved. In sFGR, large twins may show hypertrophic cardiomyopathy, and small twins may show impaired systolic function. Co-occurrence of TTTS and sFGR magnifies cardiac impact but is often underreported. Meta-analysis for CHD prevalence revealed a relative risk ratio of 3.5 (95% CI: 2.5-4.9) for TTTS and 2.2 (95%CI: 1.3-3.5) for sFGR compared with uncomplicated MC twins.

CONCLUSIONS

This study highlights the well-documented cardiac adaptation in TTTS, contrasting with limited understanding in sFGR. Elevated CHD risks were observed in both conditions. Enhanced cardiovascular surveillance is warranted in complicated MC twin pregnancies. Future research should explore cardiac adaptation in sFGR and its long-term consequences.

Vasoactive Management of Pulmonary Hypertension and Ventricular Dysfunction in Neonates Following Complicated Monochorionic Twin Pregnancies: A Single-Center Experience

OBJECTIVES

Twins resulting from a complicated monochorionic (MC) twin pregnancy are at risk for postnatal evolution of pulmonary hypertension (PH) and cardiac dysfunction (CD). Both pathologies are important contributors to short- and long-term morbidity in these infants. The aim of the present retrospective single-center cohort study was to evaluate the need for vasoactive treatment for PH and CD in these neonates.

METHODOLOGY

In-born neonates following a complicated MC twin pregnancy admitted to the department of neonatology of the University Children's Hospital Bonn (UKB) between October 2019 and December 2023 were screened for study inclusion. Finally, 70 neonates were included in the final analysis, with 37 neonates subclassified as recipient twins (group A) and 33 neonates as donor twins (group B).

RESULTS

The overall PH incidence at day of life (DOL) 1 was 17% and decreased to 6% at DOL 7 (p = 0.013), with no PH findings at DOL 28. The overall incidence of CD was 56% at DOL 1 and decreased strongly until DOL 7 (10%, p = 0.015), with no diagnosis of CD at DOL 28. The use of dobutamine, norepinephrine, and vasopressin at DOL 1 until DOL 7 did not differ between the subgroups, whereas the dosing of milrinone was significantly higher in Group B at DOL 1 (p = 0.043). Inhaled nitric oxide (iNO) was used in 16% of the cohort, and a levosimendan therapy was administered in 34% of the neonates. One-third of the cohort was treated with oral beta blockers, and in 10%, an intravenous beta blockade (landiolol) was administered. The maximum levosimendan vasoactive-inotropic score (LVISmax) increased from DOL 1 (12.4 [3/27]) to DOL 2 (14.6 [1/68], p = 0.777), with a significant decrease thereafter as measured at DOL 7 (9.5 [2/30], p = 0.011).

CONCLUSION

Early PH and CD are frequent diagnoses in neonates following a complicated MC twin pregnancy, and an individualized vasoactive treatment strategy is required in the management of these infants.

Prenatal phthalate exposure and neurodevelopmental differences in twins at 2 years of age

BACKGROUND

Previous studies of singletons evaluating prenatal phthalate exposure and early neurodevelopment reported mixed results and the associations could be biased by parental, obstetrical, and genetic factors.

METHODS

A co-twin control design was employed to test whether prenatal phthalate exposure was associated with children's neurocognitive development. We collected information from 97 mother-twin pairs enrolled in the Wuhan Twin Birth Cohort between March 2016 and October 2018. Fourteen phthalate metabolites were measured in maternal urine collected at each trimester. Neurodevelopmental differences in twins at the age of two were examined as the outcome of interest. Multiple informant model was used to examine the covariate-adjusted associations of prenatal phthalate exposure with mental development index (MDI) and psychomotor development index (PDI) scores assessed at 2 years of age based on Bayley Scales of Infant Development (Second Edition). This model also helps to identify the exposure window of susceptibility.

RESULTS

Maternal urinary levels of mono-2-ethyl-5-oxohexyl phthalate (MEOHP) (β = 1.91, 95% CI: 0.43, 3.39), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) (β = 1.56, 95% CI: 0.33, 2.79), and the sum of di-(2-ethylhexyl) phthalate metabolites (∑DEHP) (β = 1.85, 95% CI: 0.39, 3.31) during the first trimester showed the strongest and significant positive associations with intra-twin MDI difference. When stratified with twin chorionicity, the positive associations of monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), individual DEHP metabolites, and ∑DEHP exposure during pregnancy with intra-twin neurodevelopmental differences were more significant in monochorionic diamniotic (MCDA) twins than those in dichorionic diamniotic (DCDA) twins.

CONCLUSIONS

Neurodevelopmental differences in MCDA twins were strongly associated with prenatal phthalate exposure. Our findings warrant further confirmation in longitudinal studies with larger sample sizes.

Guidelines and Recommendations for Targeted Neonatal Echocardiography and Cardiac Point-of-Care Ultrasound in the Neonatal Intensive Care Unit: An Update from the American Society of Echocardiography

Targeted neonatal echocardiography (TNE) involves the use of comprehensive echocardiography to appraise cardiovascular physiology and neonatal hemodynamics to enhance diagnostic and therapeutic precision in the neonatal intensive care unit. Since the last publication of guidelines for TNE in 2011, the field has matured through the development of formalized neonatal hemodynamics fellowships, clinical programs, and the expansion of scientific knowledge to further enhance clinical care. The most common indications for TNE include adjudication of hemodynamic significance of a patent ductus arteriosus, evaluation of acute and chronic pulmonary hypertension, evaluation of right and left ventricular systolic and/or diastolic function, and screening for pericardial effusions and/or malpositioned central catheters. Neonatal cardiac point-of-care ultrasound (cPOCUS) is a limited cardiovascular evaluation which may include line tip evaluation, identification of pericardial effusion and differentiation of hypovolemia from severe impairment in myocardial contractility in the hemodynamically unstable neonate. This document is the product of an American Society of Echocardiography task force composed of representatives from neonatology-hemodynamics, pediatric cardiology, pediatric cardiac sonography, and neonatology-cPOCUS. This document provides (1) guidance on the purpose and rationale for both TNE and cPOCUS, (2) an overview of the components of a standard TNE and cPOCUS evaluation, (3) disease and/or clinical scenario-based indications for TNE, (4) training and competency-based evaluative requirements for both TNE and cPOCUS, and (5) components of quality assurance. The writing group would like to acknowledge the contributions of Dr. Regan Giesinger who sadly passed during the final revisions phase of these guidelines. Her contributions to the field of neonatal hemodynamics were immense.

Advanced imaging of fetal cardiac function

Over recent decades, a variety of advanced imaging techniques for assessing cardiovascular physiology and cardiac function in adults and children have been applied in the fetus. In many cases, technical development has been required to allow feasibility in the fetus, while an appreciation of the unique physiology of the fetal circulation is required for proper interpretation of the findings. This review will focus on recent advances in fetal echocardiography and cardiovascular magnetic resonance (CMR), providing examples of their application in research and clinical settings. We will also consider future directions for these technologies, including their ongoing technical development and potential clinical value.

Fetal Doppler in monochorionic pregnancies complicated by twin-to-twin transfusion syndrome and selective in utero growth restriction

BACKGROUND

Monochorionic (MC) twin pregnancies may be complicated by placental pathologies that impact fetal cardiac function, such as twin-twin transfusion syndrome (TTTS) and selective intrauterine growth-restriction (sIUGR). In the TTTS, the unbalanced blood flow through placental anastomoses lead a recipient volume overload, hypertension and hypertrophic cardiomyopathy and the donor twin experiences hypovolemia and hypertension due to increased placental resistance and poor renal perfusion. When MC pregnancies were complicated by sIUGR, the increase of placental resistances lead to complex fetal compensatory mechanisms with redistribution of cardiac output to vital organs. Increased placental vascular resistances, hypoxia and hemodynamic compensation mechanisms lead to higher pre and/or afterload for both ventricles, right cardiac failure and eventually left cardiac failure observed just before fetal death.

OBJECTIVES

The purpose of this study was to describe the anomalies of umbilical, ductal and aortic isthmic Doppler as well as left and right myocardial performance index (MPI) across various clinical phenotypes of MC twin pregnancies, uncomplicated or complicated by TTTS or sIUGR, in order to help differentiating these conditions and to improve the understanding of TTTS and sIUGR pathophysiology.

STUDY DESIGN

Aortic isthmic systolic index (ISI), umbilical artery pulsatility index (UAPI), ductus venosus pulsatility index (DVPI), and MPI were studied in uncomplicated MC twins (control group) and cases of sIUGR or TTTS.

RESULTS

The measurements were obtained in 113 pregnancies (24 uncomplicated, 22 sIUGR, 51 TTTS). In comparison with controls, the sIUGR smaller twin sets had lower ISI and higher UAPI, and the larger twin had higher ISI. The TTTS donor and recipient had lower ISI, higher UAPI and DVPI. Compared to the co-twin, the ISI values were lower in the sIUGR smaller twin and the TTTS donor had lower ISI and MPI. Comparing TTTS and sIUGR, the recipient had higher DVPI and MPI than the sIUGR larger twin.

CONCLUSIONS

The Doppler anomalies observed in the smaller twin reflected increased placental blood flow resistance, presumably due to abnormal feto-fetal transfusion in TTTS and to unequal placental sharing in sIUGR. Early hemodynamic changes suggestive of cardiac overload in the recipient twin may help to differentiate TTTS and sIUGR.

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.

Contribution of Ventricular Motion and Sampling Location to Discrepancies in Two-Dimensional Versus Three-Dimensional Fetal Ventricular Strain Measures

BACKGROUND

Echocardiographic quantification of fetal cardiac strain is important to evaluate function and the need for intervention, with both two-dimensional (2D) and three-dimensional (3D) strain measurements currently feasible. However, discrepancies between 2D and 3D measurements have been reported, the etiologies of which are unclear. This study sought to determine the etiologies of the differences between 2D and 3D strain measurements.

METHODS

A validated cardiac motion-tracking algorithm was used on 3D cine ultrasound images acquired in 26 healthy fetuses. Both 2D and 3D myocardial strain quantifications were performed on each image set for controlled comparisons. Finite element modeling of 2 left ventricle (LV) models with minor geometrical differences were performed with various helix angle configurations for validating image processing results.

RESULTS

Three-dimensional longitudinal strain (LS) was significantly lower than 2D LS for the LV free wall and septum but not for the right ventricular (RV) free wall, while 3D circumferential strain (CS) was significantly higher than 2D CS for the LV, RV, and septum. The LS discrepancy was due to 2D long-axis imaging not capturing the out-of-plane motions associated with LV twist, while the CS discrepancy was due to the systolic motion of the heart toward the apex that caused out-of-plane motions in 2D short-axis imaging. A timing mismatch between the occurrences of peak longitudinal and circumferential dimensions caused a deviation in zero-strain referencing between 2D and 3D strain measurements, contributing to further discrepancies between the 2.

CONCLUSIONS

Mechanisms for discrepancies between 2D and 3D strain measurements in fetal echocardiography were identified, and inaccuracies associated with 2D strains were highlighted. Understanding of this mechanism is useful and important for future standardization of fetal cardiac strain measurements, which we propose to be important in view of large discrepancies in measured values in the literature.

The heart after surviving twin-to-twin transfusion syndrome

BACKGROUND

The persistent changes in cardiac structure and function in children who survived twin-to-twin transfusion syndrome remain a matter of concern and controversy. Current fetal echocardiographic parameters and their postnatal evolution can help improve our understanding of the subject.

OBJECTIVE

To describe the echocardiographic changes of monochorionic fetuses affected by twin-to-twin transfusion syndrome, the recipient and the donor, before and after laser photocoagulation and to determine their evolution in the third trimester and during their first year of life.

STUDY DESIGN

An observational study was conducted including 55 uncomplicated monochorionic diamniotic twins and 78 pairs with twin-to-twin transfusion syndrome, 44 stage I-II and 34 stage III-IV, prospectively enrolled from 2015 until 2018. Comprehensive echocardiography was performed at 4 time periods: before laser photocoagulation, at 24 to 72 hours after surgery, at 28 to 30 weeks of gestation, and at 6 to 12 months after birth. Echocardiographic parameters were transformed to z-scores or indexed for heart area, estimated fetal weight, or body mass surface.

RESULTS

At diagnosis, recipients in all stages presented larger hearts (cardiothoracic ratio z-score: 2.77 [0.8] vs controls: -0.03 [0.5]; P<.001) and signs of ventricular hypertrophy (left end-diastolic ventricle wall thickness: 2.68 [0.7] vs controls -0.03 [0.7]; P<.001), along with systolic (cardiac index recipients: 317 [114] mL/min/kg vs controls: 400 [120] mL/min/kg, P<.001) and diastolic impairment (isovolumetric relaxation time z-score: 2.76 [0.6] vs controls: 0.05 [0.6]; P<.001). Donors presented smaller ventricular areas and diameters when compared with controls (left end-diastolic ventricle area z-score: -1.48 [1] vs 0.03 [0.9]; P<.001), along with decreased longitudinal motion (tricuspid annular plane systolic excursion z-score: -0.9 [1] vs controls -0.04 [1]; P<.001) and shorter ejection time z-score (-1.5 [0.7] vs controls: 0.0 [0.7]; P<.001). After surgery, an improvement in functional parameters was observed in both fetuses, whereas most morphometric changes prevailed in donors and recipients in the prenatal period. Postnatally, cardiac remodeling persisted in recipients (left relative wall thickness: 0.34 [0.02] vs controls: 0.30 [0.02]; P<.001), whereas donors mainly presented a decreased longitudinal motion in infancy (tricuspid annular plane systolic excursion z-score: -0.72 [0.7] vs controls: 0.23 [0.9]; P<.05).

CONCLUSION

Cardiac remodeling is present in both fetuses at the twin-to-twin transfusion syndrome diagnosis, whereas diastolic dysfunction is only significant in the recipient. Fetal therapy improves most echocardiographic parameters, although postnatally, the echocardiographic changes persist in both fetuses.

Importance of frame rate for the measurement of strain and synchrony in fetuses using speckle tracking echocardiography

OBJECTIVES

To assess the influence of frame rate settings on longitudinal strain (LS) and mechanical synchrony (SYN) values in Speckle Tracking Echocardiography (STE) of healthy fetuses.

METHODS

In this prospective study, we collected transversal or apical four-chamber-views of 121 healthy fetuses between 20 and 38 weeks of gestation using three different frame rate (FR) settings (≥ 110, 100 ± 10, 60 ± 10 frames per second). We assessed the segmental and the global LS of both ventricles (2C) and of the left ventricle (LV) offline with QLab 10.8 (Philips Medical Systems, Andover, MA, USA). Inter- and intraventricular SYN were calculated as time difference in peak myocardial strain between the mid-segments of left and right ventricle (interventricular, 2C_Syn) and lateral wall and septum of the left ventricle (intraventricular, LV_Syn), respectively.

RESULTS

In 84.3% STE was feasible at all three FR settings. The LS increased in both views at higher FRs to a statistically noticeable extent. SYN measurements and the absolute differences at patient level between the FR settings showed no statistically noticeable alterations.

CONCLUSIONS

STE is feasible at low and high FR settings. SYN emerges to be a robust parameter for fetal STE as it is less affected by the FR. High FRs enable high temporal resolutions and thus an accurate examination of fetal hearts. Future research for the technical implementation of tailored fetal STE software is necessary for reliable clinical application.

Assessment of the Size and Shape of the 4-Chamber View and the Right and Left Ventricles using Fetal Speckle Tracking in Normal Fetuses at 17-24 Gestational Weeks

INTRODUCTION

The aim of the study was to establish normal reference values obtained by fetal speckle tracking analysis of the fetal heart between 17-24 weeks of gestation among Thai fetuses and compare the nomograms with previous studies.

METHODS

The 4-chamber view of the fetal heart in 79 normal fetuses was analyzed by speckle tracking analysis to determine the best-fit regression model. The 95% reference intervals and Z-score equations of fetal cardiac parameters were computed.

RESULTS

The end-diastolic length, width, area, and circumference of the 4-chamber view (4CV) as well as the ventricular end-diastolic length, 24-segment widths, and area were all increased as a function of gestational age (GA) and 5 fetal biometric parameters. In contrast, the global sphericity index (SI), 24-segment SI, and right ventricle/left ventricle width and area ratios did not change with GA or fetal biometric measurements. There were few differences in Z-score reference ranges of fetal cardiac measurements between the current study and previous studies conducted in different patient populations.

CONCLUSION

Our study provided z-score and corresponding centile calculators, 5th and 95th centile reference tables, and corresponding graphs for evaluating the size and shape of the 4CV and the right and left ventricles using 6 independent variables between 17 and 24 weeks of gestation. These results provide normal reference ranges for future studies of fetuses with pathologies that may alter the size and shape of the 4-chamber view and ventricles.

Novel Speckle Tracking Analysis Showed Excellent Reproducibility for Size and Shape of the Fetal Heart and Good Reproducibility for Strain and Fractional Shortening

INTRODUCTION

This study aimed to evaluate reproducibility and agreement of fetal cardiac shape and deformation using FetalHQ.

METHODS

Fifty normal fetuses at 20-38 weeks of gestation were evaluated. Two operators independently selected an optimal cardiac cycle using FetalHQ®™software for speckle tracking analysis. Intra- and interobserver correlation coefficient and limits of agreement for cardiac shape and deformation were estimated.

RESULTS

Global cardiac markers: high correlation (r = 0.98) and agreement (mean difference, standard deviation [MD, SD] 5.07, 75.8) for ventricular area; moderate correlation (r = 0.78) and agreement (MD, SD: 0.016, 0.08) for global sphericity index (SI) and for left ventricle (LV) global strain (r = 0.65; MD, SD: -4.48, 11.9); and low but still significant correlation (r = 0.58) and agreement (MD, SD: -3.77, 12.27) for right ventricle (RV) global strain. For individual ventricular parameters: high correlation for LV ([median r; range] 0.98; 0.93-0.99) and RV (r = 0.98; 0.97-1.0) SI, and for LV (r = 0.92: 0.56-0.99) and RV (r = 0.96; 0.67-0.99) end diastolic diameters; moderate correlation for LV fractional shortening (r = 0.53; 0.87-0.98); and no significant correlation for RV fractional shortening (r = 0.36; 0.32-0.97). Inter- and intraobserver correlation and agreement were similar for all evaluated parameters.

CONCLUSION

Speckle tracking analysis of the fetal heart provides reliable estimations of global and LV shape and deformation. Low correlation in the RV can be related to anatomical structures such as the moderator band.

Evaluation of cardiac function in the recipient twin in successfully treated twin-to-twin transfusion syndrome using a novel fetal speckle-tracking analysis

INTRODUCTION

This study was designed to evaluate ventricular size, shape, and function in recipient twins following laser therapy for twin-twin transfusion syndrome (TTTS), using novel speckle-tracking techniques.

METHODS

This retrospective study enrolled patients that underwent fetal laser surgery for TTTS and had fetal echocardiograms (FE) performed pre- and post-operatively (op), with adequate resolution in the 4-chamber view for analysis, using a speckle-tracking software, to compute the size, shape, and function of both the right (RV) and left (LV) ventricles. Values were indexed to published normal values. Pre- and post-laser Z-score values for each of the measurements were compared using the Student's t-test, with significance defined as P < 0.05.

RESULTS

Fifteen TTTS candidate pregnancies that underwent laser therapy between 2010 and 2017, with adequate pre- and post-op FE, were selected for the analysis. Post-op FE at 28.5 ± 8.3 days showed a significant decrease in RV base dimension, increased LV base dimension, and improvements in many functional measurements: LV global and free wall strain, LV fractional area change, LV basal-apical fractional change, and LV and RV 24-segment fractional shortening (FS) of the basal segments.

CONCLUSIONS

Cardiac remodeling, following laser surgery in TTTS recipient twins, was demonstrated in the basal portion of both the RV and LV with improved biventricular function.

Fetal ventricular strain in uncomplicated and selective growth-restricted monochorionic diamniotic twin pregnancies and cardiovascular response in pre-twin-twin transfusion syndrome

OBJECTIVES

Our primary aim was to confirm whether intertwin discordance in ventricular strain and ductus venosus (DV) time intervals predicts twin-twin transfusion syndrome (TTTS). Secondary aims were to create gestational-age ranges for ventricular strain in uncomplicated monochorionic diamniotic (MCDA) twin pregnancies without selective intrauterine growth restriction (sIUGR) and to characterize the relationship of ventricular strain with gestational age in MCDA twin pregnancies with sIUGR that did not develop TTTS.

METHODS

In the period 2015-2018, we enrolled 150 MCDA twin pregnancies consecutively into this prospective, blinded study of global longitudinal left and right ventricular strain. With the observer blinded to twin pairing and pregnancy outcome, videoclips of the four-chamber view, which had been recorded during ultrasound surveillance in the usual window for development of TTTS (16-26 completed gestational weeks), underwent offline measurement of strain. Uncomplicated MCDA twin pregnancies, without sIUGR, were used to test the association between strain, gestational age and estimated fetal weight using mixed-effects multilevel regression. Inter-rater reliability was tested in 208 strain measurements in 31 fetuses from pregnancies which did not develop TTTS and within-fetus variation was assessed in 16 such fetuses, in which multiple four-chamber views were taken on the same day. The effect of sIUGR on strain in otherwise uncomplicated MCDA twin pregnancy was analyzed. MCDA twin pregnancies were defined as 'pre-TTTS' when, having been referred for TTTS evaluation, they did not satisfy Quintero staging criteria, but subsequently developed TTTS requiring laser treatment. MCDA pregnancies which did not develop TTTS comprised the 'non-TTTS' group. Cardiovascular parameters measured in these cases included tissue Doppler parameters and DV early filling time as a percentage of the cardiac cycle (DVeT%). Intertwin strain and DVeT% discordance was compared between non-TTTS and pre-TTTS cases, matched for gestational age.

RESULTS

Paired strain data were available for intertwin comparison in 127/150 MCDA twin pregnancies, comprising 14 pre-TTTS and 113 non-TTTS pregnancies, after exclusions. Scans were collected at a median frame rate of 97 (range, 28-220) Hz. Laser therapy was performed at a median gestational age of 20.6 (range, 17.2-26.6) weeks. There were no group differences in right (RV) or left (LV) ventricular strain discordance between 68/113 non-TTTS and 13/14 pre-TTTS MCDA twin pregnancies < 20 completed gestational weeks (RV, P = 0.338; LV, P = 0.932). DVeT% discordance > 3.6% was found in eight of 13 pre-TTTS pregnancies. In non-TTTS pregnancies, the estimated variability in ventricular strain within each twin during the day was high (RV, 19.7; LV, 12.9). However, within each pair (intertwin variation), variability was low (RV, 5.5; LV, 2.9). Interclass correlation reflecting the proportion of total variability represented by the variability between twin pairs was low (RV, 0.22; LV, 0.18). Both RV (P < 0.001) and LV (P = 0.025) strain showed a negative association with gestational age. Among non-TTTS MCDA twin pregnancies, LV strain was, on average, higher by 1.83 in sIUGR compared with normally grown fetuses (P = 0.023), with no statistically significant difference in RV strain (P = 0.271).

CONCLUSIONS

Although ventricular strain has been reported previously as a possible predictor of developing TTTS, in this blinded, prospective study, we found no significant intergroup differences in ventricular strain in pre-TTTS compared with age-matched non-TTTS MCDA twin pregnancies. We recommend using DVeT% discordance as a more practical screening tool in MCDA twin pregnancies. This study also provides new information on the changes with gestational age, and the biological and technical variation, of global longitudinal ventricular strain in uncomplicated MCDA twin pregnancies and those with isolated sIUGR. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal echocardiographic assessment of cardiovascular impact of prolonged support on EXTrauterine Environment for Neonatal Development (EXTEND) system

OBJECTIVE

EXTrauterine Environment for Neonatal Development (EXTEND) is a system to support ongoing fetal growth and organ development in an extrauterine environment, utilizing a pumpless low-resistance oxygenator circuit. The aim of this study was to evaluate hemodynamics and cardiac function in fetal sheep sustained on the EXTEND system.

METHODS

This was a prospective study of fetal sheep supported for a minimum of 3 weeks on EXTEND. Hemodynamic parameters were assessed weekly and included heart rate, mean arterial pressure (MAP), Doppler-echocardiography-derived cardiac output (CO), pulsatility indices (PIs) of the fetal middle cerebral artery (MCA), umbilical artery (UA) and ductus venosus and cardiac function, as assessed by speckle-tracking-derived global longitudinal strain and strain rate in the right (RV) and left (LV) ventricles. Parameters were compared at 0 days and 1, 2 and 3 weeks following placement on EXTEND.

RESULTS

Of 10 fetal sheep enrolled, seven survived for 3 weeks and were included in the analysis. Median gestational age at cannulation was 107 (range, 95-109) days. Heart rate decreased and MAP increased significantly, but within acceptable ranges, during the study period. The quantities and relative ratios of right and left CO remained stable within the anticipated physiological range throughout the study period. Vascular tracings and PIs appeared to be similar to those seen normally in the natural in-utero state, with MCA-PI being higher than UA-PI. UA tracings demonstrated maintained abundant diastolic flow despite the absence of placental circulation. In both the RV and LV, strain decreased significantly at 1 and 2 weeks relative to baseline but returned to baseline values by week 3.

CONCLUSIONS

The EXTEND mechanical support system replicates natural physiology and creates a stable and sustainable cardiovascular construct that supports growth over a 3-week period. However, there is a period of depressed contractility within the first week with subsequent improvement by week 3. This may reflect a period of physiological accommodation that warrants further investigation. This study lays the foundation for further exploration as the EXTEND system moves towards human application. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Comparison of strain and dyssynchrony measurements in fetal two-dimensional speckle tracking echocardiography using Philips and TomTec

Background The aim of this study was to compare Philips and TomTec two-dimensional speckle tracking echocardiography (2D-STE) software measurements of strain and dyssynchrony values in healthy fetuses. Methods This was an explorative observational study in which the echocardiographic data of 93 healthy fetuses between the 20th and 38th week of gestation were determined from a four-chamber view using 2D speckle tracking. The global and segmental longitudinal strain values of both ventricles, inter-ventricular and left intra-ventricular dyssynchrony were analyzed using QLab version 10.8 (Philips Medical Systems, Andover, MA, USA) and TomTec-Arena version 2.30 (TomTec, Unterschleißheim, Germany). Results TomTec showed persistently lower values for all of the assessed strain and dyssynchrony variables. For all variables, the bias between vendors tended to increase with gestational age, though not to a significant extent. Left ventricular dyssynchrony and longitudinal strain within the mid segment of the septum correlated best between vendors; however, the limits of agreement were wide in both cases. None of the variables assessed in the two-chamber view compared well between QLAB and TomTec. Conclusion Speckle tracking software cannot be used interchangeably between vendors. Further investigations are necessary to standardize fetal 2D-STE.

Advances in fetal echocardiography: myocardial deformation analysis, cardiac MRI and three-dimensional printing

PURPOSE OF REVIEW

Advances in ultrasound technology have led to new ways of evaluating cardiac function and structure, including myocardial deformation imaging (strain and strain rate), cardiac MRI and three-dimensional (3D) printing. As ultrasound technology has improved, it has become possible to use these modalities to evaluate the fetal heart. This article will review some of the more recent developments in applying these techniques to the evaluation of fetal cardiac structure and function.

RECENT FINDINGS

Myocardial deformation analyses have led to the establishment of normative values for strain and strain rate in the fetal heart and have also been used to evaluate fetal heart function in both fetal disease states and maternal disease states. Technological advances in MRI technology, 3D imaging and 3D printing have opened up new methods of evaluating fetal structural heart disease.

SUMMARY

A deeper understanding of the subtleties of myocardial dysfunction in various fetal and maternal disease states may elucidate the pathophysiology involved and lead to new treatment and/or counseling paradigms that may ultimately affect outcome. Similarly, the ability to image the fetal heart in new ways, including fetal MRI and 3D printing, could potentially change fetal counseling techniques and prenatal planning.

The value of echocardiography and Doppler in the prediction of fetal demise after laser coagulation for TTTS: A systematic review and meta-analysis

This study aimed to investigate the value of echocardiography and Doppler before fetoscopic laser coagulation for twin‐twin transfusion syndrome (TTTS) in the prediction of intrauterine fetal demise (IUFD). We performed a systematic review and meta‐analysis to compare preoperative parameters between fetuses with and without demise after laser surgery. Eighteen studies were included. Recipient twins have an increased risk of demise in case of preoperative absent/reversed flow (A/REDF) in the umbilical artery (odds ratio [OR] 2.76, 95% confidence interval [CI], 1.78‐4.28), absent or reversed a‐wave in the ductus venosus (OR 2.32, 95% CI, 1.70‐3.16), or a middle cerebral artery peak systolic velocity > 1.5 multiples of the median (MoM) (OR 7.59, 95% CI, 2.56‐22.46). In donors, only A/REDF in the umbilical artery (OR 3.40, 95% CI, 2.68‐4.32) and absent or reversed a‐wave in the ductus venosus (OR 1.66, 95% CI, 1.12‐2.47) were associated with IUFD. No association was found between donor‐IUFD and preoperative myocardial performance index (MPI). Two studies found an association between abnormal MPI and recipient demise. With this study, we have identified a set of preoperative Doppler parameters predictive of fetal demise after laser surgery. More research is needed to assess the utility of preoperative echocardiographic parameters such as the MPI in predicting IUFD.

What's already known about this topic?

Doppler parameters are associated with fetal demise after laser surgery.

Echocardiographic parameters are currently not used in risk stratification.

What does this study add?

A more extensive set of preoperative Doppler parameters is defined to predict post‐laser fetal demise.

The utility of preoperative echocardiographic parameters such as the MPI in predicting fetal demise remains unclear.

Postnatal Myocardial Function in Monochorionic Diamniotic Twins with Twin-to-Twin Transfusion Syndrome following Selective Laser Photocoagulation of the Communicating Placental Vessels

BACKGROUND

Monochorionic diamniotic (MCDA) twins are at risk for developing twin-to-twin transfusion syndrome (TTTS) throughout pregnancy. This may lead to myocardial dysfunction in the recipient and/or donor twin that persists beyond delivery. Selective laser photocoagulation of the communicating placental vessels (SLPCV) attempts to mitigate the cardiovascular outcomes. The objective of this study was to characterize early postnatal myocardial performance in MCDA twins with TTTS with and without SLPCV.

METHODS

A prospective study was performed of four MCDA twin groups: (1) uncomplicated MCDA twins, (2) MCDA twins with selective fetal growth restriction, (3) MCDA twins with TTTS following SLPCV (TTTS with SLPCV), and (4) MCDA twins with TTTS who did not undergo SLPCV (TTTS without SLPCV). Fifty-four twin pairs were enrolled: 23 uncomplicated MCDA twin pairs, 15 pairs with selective fetal growth restriction, seven TTTS pairs with SLPCV, and seven TTTS pairs without SLPCV. In each group, twin pairs were divided by birth weight into donor (smaller) and recipient (larger) and compared. Echocardiography was performed on day 1, day 2, and between days 5 and 7 of age, and myocardial performance was characterized by speckle-tracking echocardiography-derived left ventricular and right ventricular longitudinal strain (LS) and systolic strain rate (LSR). Longitudinal strain and longitudinal systolic strain rate are expressed as absolute values.

RESULTS

Compared with all recipient groups, recipient TTTS without SLPCV infants had lower left ventricular LS (16 ± 3% vs 22%-24%, P < .01) and right ventricular LS (15 ± 5% vs 21%-24%, P < .01) on day 1 that persisted throughout the first week of age. Left ventricular LSR (1.7 ± 0.3 vs 2.3 ± 0.3 sec^-1, P < .05) and right ventricular LSR (1.5 ± 0.4 vs 1.7 ± 0.5 sec^-1, P < .05) were both lower in the recipient compared with the donor twin in the TTTS without SLPCV group. LS and LSR measurements were similar among all four donor twin groups.

CONCLUSIONS

Biventricular performance is diminished in recipient MCDA twins with TTTS who are not treated with SLPCV, highlighting the need for close monitoring of their hemodynamic status during the early neonatal period.

Comparison of Longitudinal and Apical Foetal Speckle Tracking Echocardiography Using Tissue Motion Annular Displacement and Segmental Longitudinal Strain

The aim of our prospective pilot study with exploratory analysis was to compare longitudinal and apical foetal speckle tracking echocardiography (STE) using tissue motion annular displacement (TMAD) and segmental longitudinal strain (SLS). We compared two different STE quantification tools in a longitudinal and apical four-chamber view in 57 normal foetuses between 20 and 40 wk of gestation. Myocardial mechanical dyssynchrony and strain were assessed using offline quantification software (QLab Version 10.3, Philips Medical Systems, Andover, MA, USA). We compared the dyssynchrony measurements with TMAD and SLS in longitudinal and apical four-chamber views. Furthermore, we examined the segmental strain values of both ventricles with SLS and compared the differences between longitudinal and apical measurements. Dyssynchrony measurements with TMAD and SLS and strain measurements with SLS were feasible in all cases. In the apical view, the dyssynchrony measurements with TMAD were systematically greater than those achieved with SLS (p < 0.001). For the longitudinal view, no differences were observed between tools (p = 0.153). The application of SLS provided similar results for dyssynchrony in both views (intra-class correlation coefficient [ICC] = 0.281, p = 0.623), but the strain measurements in the left and right ventricles differed significantly between views (ICC = -0.082, p = 0.011, and ICC = -0.061, p = 0.024, respectively). For TMAD, we found large differences in the dyssynchrony values between longitudinal and apical assessment (ICC = -0.060, p = 0.03). Furthermore, TMAD exhibited reduced accuracy in the system's automatic tracking algorithm, limiting the data quality. The dyssynchrony assessment is affected less by the foetal position in SLS than in TMAD. The strain readings in SLS varied depending on the view in which they were assessed. The application of TMAD cannot be recommended for foetal STE.

Measurement of cardiac function by cardiac time intervals, applicability in normal pregnancy and twin-to-twin transfusion syndrome

BACKGROUND

To detect early cardiac deterioration, a simple and stable tool is needed. Measurement of time intervals in a simple 4-chamber view using color-coded tissue Doppler imaging is a relatively new approach to assess fetal cardiac function. The aim of this study was to evaluate the applicability of this modality and to construct reference ranges for cardiac time intervals.

METHODS

We performed a prospective longitudinal cohort study in healthy fetuses. We used linear mixed models to construct age-adjusted reference ranges for shortening time (St) and lengthening time (Lt) in three cardiac regions: global heart and right and left ventricular wall. St and Lt were expressed as percentage of the cardiac cycle. Feasibility and intra- and interobserver variabilities were evaluated. We applied the technique to twin-twin transfusion syndrome (TTTS) recipients before laser therapy to test the diagnostic performance.

RESULTS

A total of 251 recordings were obtained from 54 healthy singletons. St decreased and Lt increased with gestational age in all regions. We found a high feasibility (99.6%) and excellent intra-/interobserver variability for St (0.96/0.94) and Lt (0.99/0.96) of the global heart. Left and right ventricle performance parameters were good. In TTTS recipients, St was prolonged (p < 0.01) and Lt was shortened (p < 0.01) in all regions and the feasibility was excellent (96.6%).

CONCLUSIONS

The assessment of fetal cardiac function by measurement of cardiac time intervals is technically feasible with good reproducibility, even in difficult scanning circumstances such as TTTS. It is possible to discriminate between healthy and compromised fetuses with this technique.

Cardiac function and dysfunction in the fetus

Evaluation of fetal cardiac function is one of the most important components of fetal echocardiography. Fetal cardiac dysfunction is closely linked to risk of intrauterine fetal demise, in many, but not all cases is indicative of worse postnatal prognosis and may prompt the use of medications or interventions to optimize outcomes. There may be implications for termination versus continuation of pregnancy, an indication for early delivery, a change in location and even mode of delivery. In extreme cases, fetal cardiac dysfunction may prompt prenatal or early neonatal listing for cardiac transplantation. There are several important differences between the fetal and postnatal circulatory physiology which affect echocardiographic assessment of cardiac dysfunction. In this review, we examine the echocardiographic findings according to their underlying pathophysiology with reference to common causes.

Early Assessment of Right Ventricular Function in Systemic Lupus Erythematosus Patients using Strain and Strain Rate Imaging

Background

Right ventricular function is a crucial factor of the prognosis of systemic lupus erythematosus (SLE).

Objectives

To evaluate the right ventricular function in SLE patients with different degrees of pulmonary hypertension (PH) by strain and strain rate imaging.

Methods

A total of 102 SLE patients and 30 healthy volunteers were studied between October 2015 and May 2016. Patients were divided into three groups according to pulmonary artery systolic pressure (PASP) estimated by echocardiography: group control (A); PASP ≤ 30 mmHg (group B, n = 37); PASP 30-50 mmHg (mild PH; group C, n = 34); and PASP ≥ 50 mmHg (moderate-to-severe PH; group D, n = 31). Longitudinal peak systolic strain (ε) and strain rate (SR), including systolic strain rate (SRs), early diastolic strain rate (SRe) and late diastolic strain rate (SRa) were measured in the basal, middle and apical segments of the right ventricular free wall in participants by two-dimensional speckle tracking echocardiography (2D-STE) from the apical four-chamber view. A p < 0.05 was set for statistical significance.

Results

The parameters of ε, SRs, SRe, and SRa were significantly decreased in groups C and D compared with groups A and B. The ε of each segments was significantly lower in group D than in group C, while there were no differences in SRs, SRe and SRa between groups C and D.

Conclusions

Strain and strain rate imaging could early detect the right ventricular dysfunction in SLE patients with PH, and provide important value for clinical therapy and prognosis of these patients.

Factors associated to early intrauterine fetal demise after laser for TTTS by preoperative fetal heart and Doppler ultrasound

OBJECTIVE

To determine the prognostic value of fetal Doppler and echocardiographic parameters for intrauterine fetal demise (IUFD) within 24 hours and within 1 week after laser coagulation in monochorionic pregnancies complicated by twin-twin transfusion syndrome.

METHOD

This retrospective study correlated the preoperative hemodynamic and echocardiography parameters to the outcome in fetuses with twin-twin transfusion syndrome undergoing laser therapy.

RESULTS

One hundred and twelve laser coagulations were performed between February 2006 and June 2015. The total (single and double) IUFD rate was 27.7%. Further, 59% of IUFD occurred within 24 hours and 74.4% occurred within 1 week after laser. The following were associated to IUFD within 24 hours: the middle cerebral arterial pulsatility index in the donor, abnormal umbilical artery (UA) end diastolic flow, increased middle cerebral artery peak systolic velocity, and right ventricular myocardial performance index (RV-MPI) z-score in the recipient. For IUFD within 1 week were the pulsatility index in the donor UA and the recipient abnormalities in UA, ductus venosus, middle cerebral artery-peak systolic velocity, and RV-MPI z-score.

CONCLUSION

Following laser was early IUFD that was associated with Doppler findings suggesting donor cerebroplacental redistribution, and recipient overload cardiomyopathy, such as abnormal ductus venosus and UA Dopplers as well as an increase of RV-MPI.

Differential Changes in Myocardial Performance Index and Its Time Intervals in Donors and Recipients of Twin-to-Twin Transfusion Syndrome before and after Laser Therapy

OBJECTIVE

To evaluate left myocardial performance index (MPI) and time intervals in fetuses with twin-to-twin transfusion syndrome (TTTS) before and after laser surgery.

METHODS

Fifty-one fetal pairs with TTTS and 47 uncomplicated monochorionic twin pairs were included. Left ventricular isovolumetric contraction time (ICT), ejection time (ET), and isovolumetric relaxation time (IRT) were measured using conventional Doppler.

RESULTS

Recipients showed prolonged ICT (46 ± 12 vs. 31 ± 8 vs. 30 ± 5 ms; p < 0.001) and IRT (51 ± 9 vs. 43 ± 8 vs. 43 ± 5 ms; p < 0.001) and higher MPI (0.57 ± 0.12 vs. 0.47 ± 0.09 vs. 0.44 ± 0.05; p < 0.001) than donors and controls. Donors showed shorter ET than recipients and controls (157 ± 12 vs. 169 ± 10 vs. 168 ± 10 ms; p < 0.001) and higher MPI than controls (0.47 ± 0.09 vs. 0.44 ± 0.05; p = 0.006). Preoperative MPI changes were observed in all TTTS stages. Time intervals partially improved after surgery.

CONCLUSION

Donor and recipient twins had higher MPI due to different changes in the time intervals, possibly reflecting the state of hypovolemia in the donor and hypervolemia and pressure overload in the recipient.

Feasibility and Reproducibility of Two-Dimensional Wall Motion Tracking (WMT) in Fetal Echocardiography

Objective The primary objective of this study was to determine the feasibility and reproducibility of 2-dimensional speckle tracking imaging based on the wall motion tracking (WMT) technique in fetal echocardiography. The secondary objective was to compare left and right ventricular global and segmental longitudinal peak strain values. Methods A prospective cross-sectional study was performed. Global and segmental longitudinal peak strain values of the left ventricle (LV) and right ventricle (RV) were assessed prospectively. Based on apical 4-chamber views, cine loops were acquired and digitally stored. Strain analysis was performed offline. Intra- and interobserver variabilities were analyzed. Results A total of 29 healthy fetuses with an echocardiogram performed between 19 and 37 weeks of gestation were included. Analysis was performed with a temporal resolution of 60 frames per second (fps). For both examiners, in all cases Cronbach's alpha was>0.7. The interobserver variability showed a strong agreement in 50% of the segments (ICC 0.71-0.90). The global strain values for LV and RV were -16.34 and -14.65%, respectively. Segmental strain analysis revealed a basis to apex gradient with the lowest strain values in basal segments and the highest strain values in apical segments. Conclusion The assessment of fetal myocardial deformation parameters by 2D WMT is technically feasible with good reproducibility.

Two-Dimensional Speckle Tracking of the Fetal Heart: A Practical Step-by-Step Approach for the Fetal Sonologist

Various approaches to 2-dimensional speckle tracking have been used to evaluate left ventricular function and deformation in the fetus, child, and adult. In 2015, because of differences in imaging devices and analytical programs, the cardiology community published a consensus document proposing standards for pediatric/adult deformation imaging using 2-dimensional speckle tracking. The understanding and application of deformation imaging in the fetus have been limited by a lack of uniform software, terminology, techniques, and display. This article provides a practical, step-by-step approach for deformation analysis of the fetal heart using offline software that is independent of specific ultrasound vendors.

Longitudinal annular displacement by M-mode (MAPSE and TAPSE) in twin-to-twin transfusion syndrome before and after laser surgery

OBJECTIVE

To evaluate mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE) in fetuses with twin-to-twin transfusion syndrome (TTTS) before and after laser therapy.

METHODS

A prospective study in 24 fetal pairs with TTTS evaluated 24 h before and within 48 h after fetoscopy and 13 gestational age-matched normal monochorionic fetal pairs. MAPSE and TAPSE were measured in an apical or basal four-chamber view by placing the M-mode cursor at the lateral valve ring.

RESULTS

Mean preoperative MAPSE (controls 3.6 ± 1.3 mm vs. donors 2.7 ± 0.8 mm vs. recipients 2.8 mm ± 0.9; P < 0.001) and TAPSE (controls 4.4 ± 1.5 mm vs. donors 3.3 ± 1 mm vs. recipients 3.6  ± 1.1 mm; P < 0.001) values were significantly reduced in both TTTS fetuses. When subdividing according to TTTS stages, changes were significant in both stage I-II and III-IV subgroups, although differences were more pronounced in the latter. All observations remained unchanged 48 h post-fetoscopy.

CONCLUSION

Both recipient and donor fetuses had decreased global longitudinal motion, even in early TTTS stages.

Blood pressure evaluation in children treated with laser surgery for twin-twin transfusion syndrome at 2-year follow-up

OBJECTIVE

Twin survivors of twin-twin transfusion syndrome (TTTS) may be at risk for early onset of cardiovascular disease. The aim of this study was to determine prevalence and risk factors for elevated blood pressure (BP) among children treated with selective laser photocoagulation of communicating vessels.

STUDY DESIGN

Data were prospectively collected from surviving children treated for TTTS with laser surgery from 2008 through 2010. Systolic BP (SBP) and diastolic BP (DBP) were obtained from 91 child survivors at age 24 months (±6 weeks) and evaluated based on age, sex, and height percentile. BP percentiles were calculated for each patient and categorized as normal (<95%) or abnormal (>95%). Clinical variables were evaluated using multilevel regression models to evaluate risk factors for elevated BP.

RESULTS

BP was categorized as normal in 38% and abnormal in 62% of twin survivors based on percentile for sex, age, and height; a comparable distribution was found for DBP elevation. There were no differences between donor and recipient twins for absolute SBP and DBP or BP classification. In a multivariate analysis, significant risk factors for higher SBP included prematurity (β -0.54; 95% confidence interval [CI], -0.99 to -0.09; P = .02), higher weight percentile (β 0.24; 95% CI, 0.05-0.42; P = .01), and presence of cardiac disease (β 0.50; 95% CI, 0.10-0.89; P = .01). Prematurity was also a significant risk for abnormal DBP (odds ratio, 0.89; 95% CI, 0.80-1.00; P = .05).

CONCLUSION

Child survivors of TTTS had elevated SBP and DBP measurements at 2 years of age, with no differences seen between former donor and recipient twins. Prematurity may be a risk factor for elevated BP measurements in this population. Future studies are warranted to ascertain whether these cardiovascular findings persist over time.

Treatment of premature infants with pulmonary hypertension and right ventricular dysfunction with milrinone: a case series

OBJECTIVE

Milrinone has been proposed as an effective treatment for pulmonary hypertension (PH) and right ventricular (RV) dysfunction. We aimed to determine the effect of milrinone therapy on clinical and echocardiography parameters of PH in preterm infants with elevated pulmonary pressures.

STUDY DESIGN

A retrospective case review was conducted on infants <32 weeks gestation who received milrinone for the treatment of PH and reduced RV function. Echocardiographic data were collected before and after treatment with milrinone, and serial clinical parameters were recorded over a 72h  period.

RESULT

Seven infants met the inclusion criteria with a median gestation and birth weight of 27.3 weeks and 1140 g, respectively. Four infants had a diagnosis of pulmonary hypoplasia with PH, and three infants were recipients in twin-to-twin transfusion syndrome who also developed PH. Nitric oxide was used in six infants before commencement of milrinone. Milrinone was commenced at a dose of 0.33 μg kg(-1) min(-1) to 0.5 μg kg(-1) min(-1) and continued for a median duration of 70 h. Use of milrinone was associated with a fall in oxygenation index and inhaled nitric oxide dose. Following an initial fall in blood pressure over the first 6 h, there was an increase in blood pressure over the subsequent 72 h. Echocardiographic data demonstrated an increase in indicators of myocardial performance and PH. One infant died before discharge.

CONCLUSION

This case series suggests that milrinone may be a useful therapy for premature infants with echocardiography findings of PH and/or RH dysfunction. This data support the need for a randomised control trial to confirm its efficacy.

Intertwin cardiac status at 10-year follow-up after intrauterine laser coagulation therapy of severe twin-twin transfusion syndrome: comparison of donor, recipient and normal values

BACKGROUND

In twin-to-twin transfusion syndrome (TTTS), genetically identical twins are exposed to different haemodynamic conditions during fetal life, which are considered to be the cause of prenatal and postnatal cardiovascular differences between the donor and the recipient.

OBJECTIVE

To assess intertwin differences on childhood cardiac outcome after intrauterine laser coagulation therapy (LC) of severe TTTS.

DESIGN AND PATIENTS

Prospective, detailed, echocardiographic follow-up of 31 twin pairs aged 9.95±0.8 years (mean±SD) with severe TTTS treated by LC, and the comparison with reference values.

RESULTS

Cardiac function was normal and did not show intertwin differences in twins without structural heart disease. Discordant birth weight or birth weight <3rd centile for gestational age had no influence on blood pressure and cardiac indices. Pulmonary stenosis was more common (5/62; 8.1%) than in the general population (prevalence 0.066%, relative risk 134.4, 95% CI 42.1 to 428.8, p<0.0001) and affected both donor and recipient. Intertwin differences in late diastolic right ventricular filling (peak velocities: recipient 0.51±0.11 m/s vs donor 0.45±0.10 m/s, mean difference 0.74 m/s, 95% CI 0.23 to 1.24, p=0.009) and early septal relaxation (mean myocardial velocities: recipient -8.2±1.5 cm/s vs donor -8.9±1.2 cm/s, mean difference 0.7 cm/s, 95% CI 0.02 to 1.38, p=0.044) were found only when twins with right heart disease were included.

CONCLUSIONS

Despite severe prenatal cardiac involvement, childhood cardiac function is normal in the majority of surviving donors and recipients after successful LC of severe TTTS. This underlines the favourable impact of intrauterine LC on postnatal cardiovascular performance.

Impaired fetal myocardial deformation in intrahepatic cholestasis of pregnancy

OBJECTIVES

To investigate changes in fetal myocardial deformation in intrahepatic cholestasis of pregnancy.

METHODS

Patients with intrahepatic cholestasis of pregnancy were divided into 2 groups according to the total maternal serum bile acid concentration: mild cholestasis (10-40 μmol/L) and severe cholestasis (>40 μmol/L). Fetal echocardiography and velocity vector imaging were performed on women with cholestasis and control patients. The left ventricular global longitudinal strain and strain rate were measured. Clinical characteristics, maternal serum bile acid levels, and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in umbilical vein blood were compared between groups. The relationships among fetal myocardial deformation, maternal total bile acids, and cord NT-proBNP were analyzed.

RESULTS

Twenty women with mild cholestasis, 20 with severe cholestasis, and 40 control patients were enrolled. There were no significant differences in maternal and gestational ages between the case and control groups. Maternal bile acids and NT-proBNP were significantly higher in fetuses of mothers with cholestasis than control fetuses. The left ventricular longitudinal strain (-10.56% ± 1.83% versus -18.36% ± 1.11%; P < .01), systolic strain rate (-1.63 ± 0.18 versus -2.04 ± 0.18 secondsz(-1); P < .01), and diastolic strain rate (1.37 ± 0.18 versus 1.83 ± 0.14 seconds(-1); P < .01) were significantly decreased in fetuses with severe cholestasis compared with control fetuses. There were positive correlations between fetal myocardial deformation and maternal total bile acids (r = 0.705, 0.643, and 0.690, respectively; P < .01) and between myocardial deformation and NT-proBNP (r = 0.672, 0.643, and 0.647; P < .01).

CONCLUSIONS

Fetal myocardial deformation is impaired in severe intrahepatic cholestasis of pregnancy. Further investigation is needed to determine whether fetal echocardiography and velocity vector imaging can help predict which fetuses of mothers with cholestasis are likely to have poor outcomes.

Fetal right ventricular contraction and relaxation times at 11-13 weeks' gestation on speckle tracking imaging

OBJECTIVE

To examine the contraction time and relaxation time of the right ventricle at 11-13 weeks' gestation in trisomy 21 and euploid fetuses by speckle tracking ultrasound imaging.

METHODS

Measurement of fetal nuchal translucency (NT) thickness, Doppler assessment for tricuspid regurgitation and reversed A-wave in the ductus venosus (DV) and fetal echocardiography were performed immediately before chorionic villus sampling for fetal karyotyping at 11-13 weeks' gestation. Digital videoclips of the four-chamber view of the fetal heart were recorded and analyzed offline using speckle tracking imaging software. The contraction time, which is the time between the highest and lowest peaks in the right ventricular area, and relaxation time, which is the time between the lowest and the subsequent highest area peak, were measured and expressed as a percentage of the duration of the cardiac cycle. Values in trisomy 21 and euploid fetuses were compared.

RESULTS

Mean contraction time and relaxation time in 119 euploid fetuses were 52.1% (95% CI, 51.6-52.8%) and 47.8% (95% CI, 47.2-48.4%), respectively. In 21 trisomy 21 fetuses, mean contraction time was significantly higher (57.0% (95% CI, 55.2-58.9%); P<0.01) and relaxation time lower (42.9% (95% CI, 41.1-44.8%); P<0.01) than in euploid fetuses. Multiple regression analysis showed that significant contributions to contraction time and relaxation time were provided by fetal karyotype, NT and tricuspid regurgitation, but not by reversed A-wave in the DV or the presence of a cardiac defect.

CONCLUSION

In first-trimester fetuses with trisomy 21 and in euploid fetuses with increased NT and tricuspid regurgitation there is evidence of increased right ventricular contraction time and shortening of the relaxation time.

Ventricular strain changes in monochorionic twins with and without twin-to-twin transfusion syndrome

OBJECTIVE

The objective of the study was to investigate whether vector velocity imaging (VVI), a non-Doppler speckle tracking ultrasound technology, is feasible in twin pregnancies and can aid management of twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

Twenty-seven women pregnant with monochorionic diamniotic twins affected by TTTS and 28 monochorionic pregnancies that did not develop TTTS were included in a prospective case-control study at a fetal medicine center. Fetal echocardiograms were recorded with dummy electrocardiography to retain original frame rates when exported for offline speckle tracking analysis using Syngo-VVI software (Siemens Corp, Munich, Germany). Right and left ventricular (LV) free wall Lagrangian strain was measured from the original coordinates. Within-twin pair ventricular strain differences including relationship to Quintero staging and response to laser therapy for TTTS were analyzed by Wilcoxon signed-rank test.

RESULTS

The VVI strain measurements could be analyzed in 182 of 200 TTTS and 96 of 112 non-TTTS control ventricles. Within-pair strain was concordant in non-TTTS controls. Recipient LV strain was reduced at all Quintero stages compared with donors (P < .01). Recipient right ventricular strain was reduced only in stages 3 and 4 (P < .01). Strain improved at a median of 2 weeks following successful laser therapy. Intertwin differences in strain were independent of weight discordance.

CONCLUSION

Recipient LV strain is reduced in stages 1 and 2 TTTS. Within-pair strain discordance may distinguish early TTTS from growth discordance and guide timing of and management following treatment.