The area behind the heart in the four-chamber view and the quest for congenital heart defects

Fetal Pulmonary Venous Return: From Basic Research to the Clinical Value of Doppler Assessment

The fetal pulmonary circulation represents less than 25% of the fetal cardiac output. In comparison with the pulmonary arteries, studies on pulmonary veins are few and limited, and many questions remain to be answered. The literature reports that pulmonary veins play an important role in regulating vascular flow, forming an active segment of the pulmonary circulation. The development of more sophisticated ultrasonography technology has allowed the investigation of the extraparenchymal pulmonary veins and their waveform. The recognition of the pulmonary vein anatomy in echocardiography is important for the diagnosis of anomalous pulmonary venous connections, with a significant impact on prognosis. On the other hand, the identification of the normal pulmonary vein waveform seems to be a reliable way to study left heart function, with potential applicability in fetal and maternal pathology. Thus, the goal of this narrative review was to provide a clinically oriented perspective of the available literature on this topic.

Fetal left-atrial posterior-space-to-diagonal ratio at 17-37 weeks' gestation for prediction of total anomalous pulmonary venous connection

OBJECTIVES

To develop normative data for the left-atrial posterior-space-to-diagonal (LAPSD) ratio and post-left atrium space (PLAS) index in fetuses from 17 to 37 weeks' gestation, and determine the optimal cut-offs of the LAPSD ratio and PLAS index to discriminate between normal fetuses and those with total anomalous pulmonary venous connection (TAPVC).

METHODS

This was a prospective cross-sectional assessment of 428 structurally normal fetuses between 17 and 37 weeks' gestation and a retrospective study of 27 TAPVC fetuses. The fetal LAPSD ratio was calculated by dividing the left atrium-descending aorta distance (LDD) by the left atrial diagonal diameter (LA). The PLAS index was calculated as the ratio of the LDD to the descending aorta diameter (DA). Pearson's correlation analysis was used to examine the correlation of cardiac parameters with gestational age (GA) and fetal somatic growth. The PLAS index and LAPSD ratio were compared between the normal and TAPVC groups to assess their usefulness in the prenatal diagnosis of TAPVC.

RESULTS

LDD, LA and DA measures showed moderate to strong positive correlation, whereas both the LAPSD ratio and PLAS index showed a slight decrease with increasing GA and biometric variables. The fetal LAPSD ratio and PLAS index in TAPVC cases were significantly greater compared with those of fetuses with a normal heart (both P < 0.001). There were no significant differences in the PLAS index and LAPSD ratio between the isolated and complex TAPVC groups (both P = 1). No significant associations of the PLAS index and LAPSD ratio with fetal gender, four-chamber view type (apical, basal or lateral) or TAPVC type were found. Using values of ≥ 0.35 for the LAPSD ratio and of ≥ 1 for the PLAS index exhibited similar excellent diagnostic performance, with a sensitivity of 100% and specificity of 97.0% or 95.1% for detecting TAPVC.

CONCLUSIONS

Our study demonstrates that the LAPSD ratio is a practical and effective screening tool for diagnosing fetal TAPVC, similar to the PLAS index. Incorporating these parameters into routine cardiac scanning may enhance the prenatal detection of TAPVC. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Diagnosis of fetal total anomalous pulmonary venous connection based on the post-left atrium space ratio using artificial intelligence

OBJECTIVE

To explore whether the post-left atrium space (PLAS) ratio would be useful for prenatal diagnosis of total anomalous pulmonary venous connection (TAPVC) using echocardiography and artificial intelligence.

METHODS

We retrospectively included 642 frames of four-chamber view from 319 fetuses (32 with TAPVC and 287 without TAPVC) in end-systolic and end-diastolic periods with multiple apex directions. The average gestational age was 25.6±2.7 weeks. No other cardiac or extracardiac malformations were observed. The dataset was divided into a training set (n=540; 48 with TAPVC and 492 without TAPVC) and test set (n=102; 20 with TAPVC and 82 without TAPVC). The PLAS ratio was defined as the ratio of the epicardium-descending aortic distance to the center of the heart-descending aortic distance. Supervised learning was used in DeepLabv3+, FastFCN, PSPNet, and DenseASPP segmentation models. The area under the curve (AUC) was used on the test set.

RESULTS

Expert annotations showed that this ratio was not related to the period or apex direction. It was higher in the TAPVC group than in the control group detected by expert and the four models. The AUC of expert annotations, DeepLabv3+, FastFCN, PSPNet, and DenseASPP were 0.977, 0.941, 0.925, 0.856, and 0.887, respectively.

CONCLUSION

Segmentation models achieve good diagnostic accuracy for TAPVC based on the PLAS ratio. This article is protected by copyright. All rights reserved.

Prenatal Diagnosis of Pulmonary Atresia With Ventricular Septal Defect and an Aberrant Ductus Arteriosus in a Dextrocardia by Two- and Three-Dimensional Echocardiography: A Case Report

Introduction

Prenatal diagnosis of pulmonary atresia is difficult in relative, especially when the pulmonary artery is slim and hypoplastic in development. It is of great importance to search for the blood supply to the pulmonary artery in those fetuses while it challenges most screening sonographers, even fetal echocardiography specialists. We herein report a rare case of pulmonary atresia with ventricular septal defect, complicated with an aberrant ductus arteriosus which provides the blood supply to the pulmonary artery. Besides, the case was also accompanied by cardiac malposition, dextrocardia with situs solitus. The echocardiographic characteristics and autopsy findings are also presented to approach the skill of fetal diagnosis.

Case presentation

A 30-year-old primigravida woman was referred to our center at gestational age of (24 ± 3) weeks for further fetal cardiac examination for suspected fetal cardiac anomalies. Fetal echocardiography revealed dextrocardia, situs solitus of the atria, an L-ventricular loop, a ventricular septal defect, an enlarged coronary sinus, and pulmonary atresia by transverse scanning. The ductus arteriosus was not present at the three-vessel trachea view with the retrograde flow showing in the pulmonary artery trunk, which suggested the possibility of an aberrant ductus arteriosus. Sagittal and coronal scanning was attempted to find that the pulmonary artery connected with the innominate artery via the aberrant ductus arteriosus. Three-dimensional echocardiography with spatio-temporal image correlation and high-definition flow imaging technique was performed to obtain the three-dimensional rendered image, which clearly showed the malformation in space. The pregnancy was terminated and the gross findings confirmed the prenatal diagnosis.

Conclusion

A detailed evaluation of fetal cardiac anatomy and hemodynamics is crucial for the detection of an aberrant ductus arteriosus, which plays an important role in the diagnosis of pulmonary atresia with ventricular septal defect. Sagittal and coronal scanning is useful to find the course of this aberrant ductus arteriosus. The three-dimensional echocardiography with spatio-temporal image correlation technique could provide additional spatial information to show great arteries in detail, which can serve as a supplement to traditional two-dimensional modality and benefit examiners to make an accurate diagnosis.

Post-Left Atrium Space Index in Fetuses With Total Anomalous Pulmonary Venous Connection and Other Congenital Heart Diseases

OBJECTIVES

We aimed to explore the value of the post-left atrium space (PLAS) index in the diagnosis of total anomalous pulmonary venous connection (TAPVC) and the effect of other congenital heart diseases on the PLAS index in the fetus.

METHODS

The PLAS index of 69 fetuses with TAPVC was analyzed retrospectively. Approximately 252 healthy fetuses were randomly selected as controls, and 110 cases of intracardiac malformations were randomly selected for comparison. The PLAS index was defined as the ratio of the left atrium-descending aorta distance divided by the descending aorta diameter from the 4-chamber view in the end-systolic phase.

RESULTS

There were no significant differences in the PLAS index among the 3 groups of isolated TAPVC subtypes (P > .05), or among the isolated TAPVC group and the simple and complex cardiac anomaly groups (P > .05). Compared with the control group, the PLAS index of the TAPVC group was significantly increased (P < .001). The PLAS index was significantly higher in the TAPVC group than in hypoplastic left heart syndrome, endocardial cushion defect, conotruncal defect, and ventricular septal defect groups (P < .05). The PLAS indices of the hypoplastic left heart syndrome, endocardial cushion defect, and conotruncal defect groups were all higher than that of the control group (P < .05). There was no significant difference in the PLAS index between the ventricular septal defect and control groups (P > .05).

CONCLUSIONS

The PLAS index is a sensitive parameter for the diagnosis of fetal TAPVC. There were no significant differences in the PLAS index among different TAPVC types. Complex intracardiac anomalies have an influence on the PLAS index.

Evaluation of the post-LA space index in the normal fetus

OBJECTIVE

We previously reported the post-LA space index (PLAS index), which is calculated as left atrial-descending aorta distance (LD) divided by the diameter of descending aorta (DA), could be useful for prenatal diagnosis of total anomalous pulmonary venous connection (TAPVC). In this study, we evaluated PLAS index in normal fetuses to assess its usefulness.

METHODS

In 304 normal fetuses, LD and DA were retrospectively measured, and the PLAS index was calculated. In 206 fetuses with data on the biparietal diameter (BPD) and femoral length (FL), the relationship between the PLAS index and them was investigated. We also calculated the PLAS index in 13 TAPVC fetuses.

RESULTS

Mean LD was 3.0+/-0.94 mm, mean DA was 4.8+/-0.87 mm, and the mean PLAS index was 0.62+/-0.19. DA and LD were correlated with gestational age (R = 0.52, 0.25), while the PLAS index showed little variation with gestational age (R < 0.2). BPD and FL were correlated with DA (R = 0.4, 0.42) but not with LD or the PLAS index (both R < 0.2). In the TAPVC fetuses, both LD and the PLAS index were significantly higher than in normal fetuses.

CONCLUSION

In normal fetuses, the PLAS index was independent of gestational age and fetal physique and may be useful for raising the suspicion of congenital heart disease, including TAPVC.

A Pathogenic Homozygous Mutation in The Pleckstrin Homology Domain of RASA1 Is Responsible for Familial Tricuspid Atresia in An Iranian Consanguineous Family

Objective

Tricuspid atresia (TA) is a rare life-threatening form of congenital heart defect (CHD). The genetic mechanisms underlying TA are not clearly understood. According to previous studies, the endocardial cushioning event, as the primary sign of cardiac valvulogenesis, is governed by several overlapping signaling pathways including Ras/ ERK pathway. RASA1, a regulator of cardiovascular development, is involved in this pathway and its haploinsufficiency (due to heterozygous mutations) has been identified as the underlying etiology of the autosomal dominant capillary malformation/arteriovenous malformation (CM/AVM).

Materials and Methods

In this prospective study, we used whole exome sequencing (WES) followed by serial bioinformatics filtering steps for two siblings with TA and early onset CM. Their parents were consanguineous which had a history of recurrent abortions. Patients were carefully assessed to exclude extra-cardiac anomalies.

Results

We identified a homozygous RASA1 germline mutation, c.1583A>G (p.Tyr528Cys) in the family. This mutation lies in the pleckstrin homology (PH) domain of the gene. The parents who were heterozygous for this variant displayed CM.

Conclusion

This is the first study reporting an adverse phenotypic outcome of a RASA1 homozygous mutation. Here, we propose that the phenotypic consequence of the homozygous RASA1 p.Tyr528Cys mutation is more serious than the heterozygous type. This could be responsible for the TA pathogenesis in our patients. We strongly suggest that parents with CM/AVM should be investigated for RASA1 heterozygous mutations. Prenatal diagnosis and fetal echocardiography should also be carried out in the event of pregnancy in heterozygous parents.

The ultrasound appearance of an unusual fetal pericardial cyst

We describe the prenatal and postnatal sonographic findings and postnatal course in the first reported patient with a posterior mediastinal pericardial cyst. We then review and discuss current knowledge about the management of prenatally diagnosed cystic structures of the pericardium. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:149-151, 2018.

Reliability of posterior-left atrium space index measurements during 20-24 weeks of gestation in structurally normal fetuses

OBJECTIVE

We aimed to evaluate the correlation between clinical parameters and the post-left atrium (LA) space index, which is a candidate screening marker for total anomalous pulmonary venous connection (TAPVC). We also calculated the inter- and intra-observer variabilities of measurements for this parameter.

METHODS

The LA-descending aorta distance/descending aorta diameter ratios (post-LA space index) were obtained from 165 fetuses between 20 and 24 weeks of gestation. Regression analyses were utilized to evaluate the correlations across clinical parameters and the post-LA space index. Intraclass correlations coefficients were calculated for the intra- and inter-observer agreements of three examiners with different sonographic experience.

RESULTS

The mean (±SD) maternal and gestational age (GA) was 28.6±4.9 years and 21.7±0.9 weeks of gestation, respectively. In multivariate analyses, there was no correlation between post-LA space index and maternal age, fetal gender, or GA at cardiac scan. There were moderate to strong correlations across the measurements by different examiners, indicating good inter- and intra-observer agreements.

CONCLUSION

The post-LA space index during 20-24 weeks of gestation is a simple and reliable marker that is not affected by GA. However, its potential as a screening tool for TAPVC warrants further clinical investigation.

Prenatal and Postnatal Survival of Fetal Tetralogy of Fallot: A Meta-analysis of Perinatal Outcomes and Associated Genetic Disorders

OBJECTIVES

The aim of this systematic review was to compare the postnatal outcomes, genetic testing results, and sonographic findings in 3 subtypes of tetralogy of Fallot.

METHODS

Thirty-six articles from the MEDLINE and EMBASE databases were selected for this review. The postnatal outcomes, karyotyping results, and sonographic findings of fetal tetralogy of Fallot with pulmonary stenosis, tetralogy of Fallot with pulmonary atresia, and tetralogy of Fallot with an absent pulmonary valve were collected and compared.

RESULTS

The survival rates (termination of pregnancy was considered fetal death) for prenatally diagnosed tetralogy of Fallot with pulmonary atresia and tetralogy of Fallot with an absent pulmonary valve at the end of neonatal period were significantly lower than the rate for tetralogy of Fallot with pulmonary stenosis (P < .05). The survival rate for tetralogy of Fallot with pulmonary atresia was also lower at birth (P < .001). Major chromosomal anomalies were more frequently detected in tetralogy of Fallot with pulmonary stenosis (P< .05); conversely, 22q11 deletion was present more often in fetuses with tetralogy of Fallot with pulmonary atresia and tetralogy of Fallot with an absent pulmonary valve (P < .001). Compared to tetralogy of Fallot with pulmonary stenosis, a right aortic arch was more associated with tetralogy of Fallot with pulmonary atresia (32.6%; P < .05), and the ductus arteriosus was almost always absent in tetralogy of Fallot with an absent pulmonary valve (87.5%; P < .001).

CONCLUSIONS

The postnatal outcomes, genetic testing results, and sonographic findings are different among subtypes of tetralogy of Fallot. Documenting those details at diagnosis can help specialists better counsel their patients.

'Post-LA space index' as a potential novel marker for the prenatal diagnosis of isolated total anomalous pulmonary venous connection

OBJECTIVES

To review the fetal echocardiograms of patients with total anomalous pulmonary venous connection (TAPVC) in order to determine whether the distance between the left atrium and the descending aorta would be useful in the prenatal diagnosis of fetal TAPVC.

METHODS

We reviewed the fetal echocardiograms of eight cases of TAPVC (five supracardiac type and three infracardiac type) with no other cardiac malformations. We evaluated the ratio of the left atrium-descending aorta distance to the diameter of the descending aorta ('post-LA space index') in 101 normal and eight TAPVC fetuses, and compared the values between groups. In addition, we examined the tricuspid valve/mitral valve diameter ratio (TVD/MVD) and the right ventricular end-diastolic diameter/left ventricular end-diastolic diameter ratio (RVDd/LVDd).

RESULTS

The echocardiograms for fetuses with TAPVC and normal fetuses were performed at mean gestational ages of 27.5 weeks and 29.6 weeks, respectively. There were no significant differences in the TVD/MVD and RVDd/LVDd ratios between the groups. However, the post-LA space index was significantly higher in the TAPVC cases (mean, 1.51) than it was in the normal fetuses (mean, 0.71 ± 0.23) (P < 0.0001). On an analysis of the receiver-operating characteristics curve, a post-LA space index cut-off of 1.27 was found to be optimal for distinguishing between TAPVC and normal hearts, with a sensitivity of 100% and specificity of 99%.

CONCLUSIONS

The novel post-LA space index could potentially be used for the prenatal diagnosis of TAPVC. A diagnosis of TAPVC is very likely in cases with a post-LA space index of > 1.27.

A novel systematic approach to the evaluation of the fetal venous system

Sonographic evaluation of the fetal venous system in normal and abnormal conditions has drawn increasing interest in recent years. Whereas the assessment of the fetal heart and the related arteries is standardized using well-defined planes, the fetal venous system is still lacking a systematic approach. In this article we present a novel sonographic algorithm for a systematic examination of the fetal venous system using six planes of transverse and oblique views of the fetal abdomen and chest. These planes, using two-dimensional and color Doppler, enable a targeted demonstration of the typical veins to include the umbilical vein, ductus venosus, portal veins, hepatic veins, inferior vena cava, azygos vein, pulmonary veins, coronary sinus, superior vena cava and brachiocephalic vein. We postulate that integrating such a sequential stepwise algorithm for the evaluation of the venous system into targeted fetal cardiac imaging may improve the detection of isolated and combined anomalies of the fetal systemic and pulmonary veins.

Defining laterality of the descending thoracic aorta in a 4-chamber view of the heart

OBJECTIVE

Right descending aortas have been correlated with an increased risk of congenital heart disease. Nevertheless, the aortic position remains a largely overlooked diagnostic tool in second-trimester sonography because no formal system for assessing the position exists. By developing a method of assigning the position of the aorta relative to the thoracic midline, diagnostic use of the descending aorta's position might be implemented more easily.

METHODS

The method of assessing the position relative to the midline was tested by comparing the analysis of 2 independent observers, who showed a 94.4% concordance rate.

RESULTS

Comparison of the percentages of aortic positions between the gestational ages (GAs) of 18 and 21 weeks showed no significant correlation between the aortic position and GA.

CONCLUSIONS

We suggest simply paying attention to the aortic position in an already standard view. The extra effort is minimal, and it has the potential to improve the diagnostic accuracy of the 4-chamber view.

Prenatal diagnosis of tricuspid atresia: intrauterine course and outcome

OBJECTIVE

To evaluate the intrauterine course and outcome of tricuspid atresia detected in the fetus.

METHODS

This was a retrospective review of all confirmed cases of tricuspid atresia detected prenatally between 1998 and 2006 in three tertiary referral centers in Germany.

RESULTS

Fifty-four cases of tricuspid atresia were detected prenatally during the study period and confirmed postnatally: 28 (51.9%) cases had a concordant ventriculoarterial connection of which 14 also had pulmonary outflow obstruction; 25 (46.3%) cases had a discordant ventriculoarterial connection of which 14 also had aortic outflow obstruction, six had pulmonary outflow tract obstruction and two had other associated intracardiac anomalies; and one (1.9%) had a common arterial trunk. The peak velocity index for veins in the ductus venosus was significantly elevated in 19 of the 37 (51.4%) cases assessed; however, this finding did not correlate with adverse intrauterine outcome. There were associated extracardiac anomalies in 12 cases: five with chromosomal anomalies, two with VACTERL association, one with unilateral renal agenesis, one with hypospadia, one with hydrothorax, one with megacystis and one with agenesis of the ductus venosus. Seventeen of the 54 (31.5%) cases underwent termination of pregnancy, two (3.7%) died in utero, two (3.7%) died in infancy and 33 (61.1%) children survived with a median follow-up of 26 (range, 12-120) months. Prenatal echocardiography correctly anticipated the postnatal course and the need for neonatal intervention in 29/35 (82.9%) continued pregnancies; in the remaining six (17.1%) cases the right outflow tract obstruction had been underestimated.

CONCLUSIONS

Tricuspid atresia and the frequently associated intracardiac anomalies can be diagnosed in the fetus with considerable accuracy. A thorough search for extracardiac malformations should be performed in order to rule out chromosomal anomalies and multiple malformation syndromes. Elevated pulsatility in the ductus venosus does not indicate cardiac failure. The short-term overall survival in continued pregnancies in our study exceeded 89%, with the greatest rate of loss being in the first year of postnatal life.