Ultrasound evaluation of aortic valve anatomy in the fetus

Fetal echocardiographic features associated with bicuspid aortic valve

BACKGROUND

Prenatal diagnosis of bicuspid aortic valve is challenging. Bicuspid aortic valve is often associated with aortic dilation.

METHODS

Fetuses with postnatally confirmed bicuspid aortic valve were gestational age-matched with normal controls. Complex lesions were excluded. Aortic valve and arch measurements by two blinded investigators were compared.

RESULTS

We identified 27 cases and 27 controls. Estimated fetal weight percentile was lower in cases than controls. Seven cases had one or more significant lesions including perimembranous ventricular septal defects (n = 2), isolated annular hypoplasia (n = 2), and/or arch hypoplasia/coarctation (n = 4). Fetuses with bicuspid aortic valves had significantly smaller median z-scores of the aortic annulus (-1.60 versus -0.53, p < 0.001) and root (-1.10 versus -0.53, p = 0.040), and larger ratios of root to annulus (1.32 versus 1.21, p < 0.001), sinotubular junction to annulus (1.07 versus 0.99, p < 0.001), ascending aorta to annulus (1.29 versus 1.18, p < 0.001), and transverse aorta to annulus (1.04 versus 0.96, p = 0.023). Leaflets were "doming" in 11 cases (41%) and 0 controls (p = 0.010), "thickened" in 10 cases (37%) and 0 controls (p = 0.002). We noted similar findings in the subgroup without significant additional cardiac defects.

CONCLUSIONS

The appearance of doming or thickened aortic valve leaflets on fetal echocardiogram is associated with bicuspid aortic valve. Compared to controls, fetuses with bicuspid aortic valve had smaller aortic annulus sizes (possibly related to smaller fetal size) without proportionally smaller aortic measurements, resulting in larger aortic dimension to annulus ratios. Despite inherent challenges of diagnosing bicuspid aortic valve prenatally, these findings may increase suspicion and prompt appropriate postnatal follow-up.

Prenatal cardiac biometry and flow assessment in fetuses with bicuspid aortic valve at 20 weeks' gestation: multicenter cohort study

OBJECTIVE

To investigate prenatal changes in cardiac biometric and flow parameters in fetuses with bicuspid aortic valve (BAV) diagnosed neonatally compared with controls with normal cardiac anatomy.

METHODS

This analysis was conducted as part of the Copenhagen Baby Heart Study, a multicenter cohort study of 25 556 neonates that underwent second-trimester anomaly scan at 18 + 0 to 22 + 6 weeks' gestation and neonatal echocardiography within 4 weeks after birth, in Copenhagen University Hospital Herlev, Hvidovre Hospital and Rigshospitalet in greater Copenhagen, between April 2016 and October 2018. From February 2017 (Rigshospitalet) and September 2017 (Herlev and Hvidovre hospitals), the protocol for second-trimester screening of the heart was extended to include evaluation of the four-chamber view, with assessment of flow across the atrioventricular valves, sagittal view of the aortic arch and midumbilical artery and ductus venosus pulsatility indices. All images were evaluated by two investigators, and cardiac biometric and flow parameters were measured and compared between cases with BAV and controls. All cases with neonatal BAV were assessed by a specialist. Maternal characteristics and first- and second-trimester biomarkers were also compared between the two groups.

RESULTS

Fifty-five infants with BAV and 8316 controls with normal cardiac anatomy were identified during the study period and assessed using the extended prenatal cardiac imaging protocol. There were three times as many mothers who smoked before pregnancy in the group with BAV as in the control group (9.1% vs 2.7%; P = 0.003). All other baseline characteristics were similar between the two groups. Fetuses with BAV, compared with controls, had a significantly larger diameter of the aorta at the level of the aortic valve (3.1 mm vs 3.0 mm (mean difference, 0.12 mm (95% CI, 0.03-0.21 mm))) and the pulmonary artery at the level of the pulmonary valve (4.1 mm vs 3.9 mm (mean difference, 0.15 mm (95% CI, 0.03-0.28 mm))). Following conversion of the diameter measurements of the aorta and pulmonary artery to Z-scores and Bonferroni correction, the differences between the two groups were no longer statistically significant. Pregnancy-associated plasma protein-A (PAPP-A) multiples of the median (MoM) was significantly lower in the BAV group than in the control group (0.85 vs 1.03; P = 0.04).

CONCLUSIONS

Our findings suggest that fetuses with BAV may have a larger aortic diameter at the level of the aortic valve, measured in the left-ventricular-outflow-tract view, and a larger pulmonary artery diameter at the level of the pulmonary valve, measured in the three-vessel view, at 20 weeks' gestation. Moreover, we found an association of maternal smoking and low PAPP-A MoM with BAV. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of neonatal coarctation of the aorta at fetal echocardiography: a scoring system

INTRODUCTION

Coarctation of the aorta (CoA) is common and can lead to neonatal emergency. Despite its burden, antenatal detection of this condition remains inaccurate.

OBJECTIVE

To evaluate the diagnostic performance of fetal echocardiography and to design a scoring system for risk stratification of CoA in suspected cases.

DESIGN

A retrospective cohort study.

SETTING

S. Orsola Hospital, Bologna, Italy.

POPULATION

About 140 fetuses referred for suspected CoA to our tertiary center in a 9-year period.

METHODS

The following parameters were systematically obtained at fetal echocardiography: ventricular disproportion, great vessels asymmetry, transverse aortic arch hypoplasia, flow turbulence, and Z-scores of the ascending aorta and of the aortic isthmus. Associated anomalies were recorded, if present. When CoA was not confirmed at birth, neonates were followed up for 12 months to identify also a tardive onset of this condition.

MAIN OUTCOME MEASURES

The primary outcome was the presence of COA after birth.

RESULTS

108 fetuses were eligible for the purpose of the study. CoA was confirmed postnatally in 55 neonates (50.9%). Arch hypoplasia yielded the highest correlation with CoA. The affected neonates presented also significantly lower Z scores of the ascending aorta and of the aortic isthmus. Earlier gestational age at referral was positively correlated with neonatal CoA. An odds ratio-based multiparametric model was designed to build a scoring system (AUC 0.89).

CONCLUSION

In our cohort, no single ultrasound parameter was sufficiently accurate to predict postnatal CoA. The scoring system permitted a better identification of the affected fetuses.

Original paper. Do Umbilical Cord Wrapped Around the Fetal Body Can Mimic Signs of Aortal Coarctation?

Objectives: Coarctation of the aorta (CoA) is an irreversible congenital heart defect. Its prenatal diagnosis is not rare a subject to false-positive conclusion. We present a novel hypothesis explaining the basis of this error.

Methods: Ten cases of prenatal suspicion of the coarctation of the aorta (based on disproportion at the level of 4 chamber view and mediastinum) coincidenced with the umbilical cord wrapped around the fetal body were found in the Filemaker datebase of the Fetal Cardiology Department. Only single pregnancies were taken into account. In all cases another cardiac and extracardiac malformations were excluded.

Results: The mean maternal age was 29,6 years. The mean gestational age was 33 7/8 weeks. All fetuses were in a good cardiovascular condition. The usual position of the umbilical cord was neck, but they were also location such as nucha, abdomen or lower limb. At birth, all newborns had normal anatomy of the heart. We conclude that the explanation of the false diagnosis was haemodynamic, resulting from the compression of the fetal neck by the umbilical cord that resulted in a disproportion of cardiac blood flow, “mimicking” CoA.

Conclusions:

1. Functional disturbances can mimic prenatal CoA.

2. Umbilical cord position (specially enlacing the fetus neck) should be taken into consideration in suspected cases of fetal CoA.

Prenatal Sonographic Predictors of Neonatal Coarctation of the Aorta

OBJECTIVES

To identify practical prenatal sonographic markers for the postnatal diagnosis of coarctation of the aorta.

METHODS

We reviewed the fetal echocardiograms and postnatal outcomes of fetal cases of suspected coarctation of the aorta seen at a single institution between 2010 and 2014. True- and false-positive cases were compared. Logistic regression analysis was used to determine echocardiographic predictors of coarctation of the aorta. Optimal cutoffs for these markers and a multivariable threshold scoring system were derived to discriminate fetuses with coarctation of the aorta from those without coarctation of the aorta.

RESULTS

Among 35 patients with prenatal suspicion of coarctation of the aorta, the diagnosis was confirmed postnatally in 9 neonates (25.7% true-positive rate). Significant predictors identified from multivariate analysis were as follows: Z score for the ascending aorta diameter of -2 or less (P = < .001), Z score for the mitral valve annulus of -2 or less (P= .033), Zscore for the transverse aortic arch diameter of -2 or less (P= .028), and abnormal aortic valve morphologic features (P= .026). Among all variables studied, the ascending aortic Z score had the highest sensitivity (78%) and specificity (92%) for detection of coarctation of the aorta. A multivariable threshold scoring system identified fetuses with coarctation of the aorta with still greater sensitivity (89%) and only mildly decreased specificity (88%).

CONCLUSIONS

The finding of a diminutive ascending aorta represents a powerful and practical prenatal predictor of neonatal coarctation of the aorta. A multivariable scoring system, including dimensions of the ascending and transverse aortas, mitral valve annulus, and morphologic features of the aortic valve, provides excellent sensitivity and specificity. The use of these practical sonographic markers may improve prenatal detection of coarctation of the aorta.

Left ventricular remodelling in outflow tract obstructive lesions during fetal life

OBJECTIVE

Left ventricular (LV) remodelling in prenatally diagnosed LV outflow tract obstructive lesions such as aortic stenosis and aortic coarctation is important for prenatal counselling and postnatal management. The purpose of this study was to document the spectrum and the progression of different LV remodelling patterns and to identify prenatal markers of hypoplastic left heart syndrome (HLHS).

METHODS

We studied 29 fetuses with LV outflow tract obstruction: 13 with isolated aortic stenosis, 14 with isolated aortic coarctation and two with combined aortic stenosis and aortic coarctation. Echocardiographic evaluation was performed 4 and 8 weeks after the first observation and at birth.

RESULTS

None of the fetuses had HLHS (LV end-diastolic diameter z score higher than -2) at first prenatal echocardiography (24.5 + or - 3.6 weeks). Fetuses were divided into two groups: group A (n = 25) with a LV end-diastolic volume at birth > 20 ml/m(2); group B (n = 4) with a LV end-diastolic volume at birth < 20 ml/m(2) (LV hypoplasia). At first echocardiographic evaluation, the two groups showed a significantly different aorta to pulmonary ratio (0.44 + or - 0.08 vs. 0.86 + or - 0.14; P < 0.001); other LV echocardiographic features were not significantly different. The growth of the mitral (0.10 + or - 0.02 vs. 0.43 + or - 0.28 mm/week; P < 0.02) and aortic annulus (0.08 + or - 0.01 vs. 0.26 + or - 0.14 mm/week; P < 0.05) was significantly slower in group B.

CONCLUSIONS

Our data suggest that LV outflow tract obstruction can progressively evolve in HLHS during pregnancy. A smaller aorta to pulmonary ratio was the only significant difference at initial echocardiographic evaluation in the two groups. Moreover, serial echocardiographic examinations are necessary to recognize fetuses at risk for HLHS caused by a subnormal growth rate of the mitral and aortic annulus.

Latest advances and topics in fetal echocardiography

PURPOSE OF REVIEW

Fetal diagnosis and the supporting specialties of perinatology, neonatology, and surgery have made rapid strides in the last decade. Numerous centers are focusing on this multifaceted niche area as the medical field realizes its vast promise and potential. The authors review some of the major advancements in thought and practice in the field of fetal echocardiography while attempting to give a less detailed overview for the less involved perinatologist.

RECENT FINDINGS

First trimester fetal echocardiography has been an area of recent interest as transducer technology improves. As a result, optimum timing of first and subsequent scans and the population profile they are to be applied to have become an issue that begs consensus. Three-dimensional and four-dimensional fetal echocardiography have also received a boost for the same reasons, and both are being studied for feasibility and accuracy. Fetal tissue Doppler and spectral Doppler imaging are potential areas for exploration; the early steps have been taken. Awareness of associated ultrasound markers, such as exaggerated nuchal translucency, as clues to the presence of congenital heart disease is important, even if controversial.

SUMMARY

The issue of missed prenatal diagnosis is disturbing, especially when it arises against a background of tremendous skill and technologic support. Strategies to minimize mistakes in this critical aspect need to be agreed on by the involved teams and put in place in a multidisciplinary manner if they are to have an important impact.