Perinatal and infant outcomes of prenatal diagnosis of heterotaxy syndrome (asplenia and polysplenia)

The Clinical Outcomes in Patients With Atrial Isomerism Undergoing Single Ventricular Palliation: Insights From A Single-Center Study in Thailand

Background: The management of atrial isomerism across various countries may impact survival outcomes. Methods: This retrospective study involved patients diagnosed with atrial isomerism undergoing single ventricular palliation between 2000 and 2021. The objective was to evaluate survival outcomes within the right atrial isomerism (RAI) and left atrial isomerism (LAI) groups, as well as overall survival. Results: Of the 125 patients diagnosed with atrial isomerism, 105 (84%) had RAI, and 20 (16%) had LAI. The median age at presentation was 3 days (range: birth to 7.1 years), with median follow-up of 6.6 years (range: 0.59 months to 30.8 years). In the overall cohort, survival rates at one, five, and ten years were 85.6%, 72.3%, and 66.8%, respectively, with no statistically significant difference between RAI and LAI groups (log rank P value = .293). Specifically, survival rates in the RAI group at one, five, and ten years were 83.8%, 69.0%, and 62.6%, respectively, while in the LAI group, there were 95.0%, 89.7%, and 81.6%, respectively. Following the third-stage operation, overall survival rates at one and five years were 76.4% and 76.4%, respectively. Among patients in the RAI group, survival rates at one and five years post-third stage operation were 80.2% and 80.2%, respectively. Conclusions: Despite resource limitations, the survival outcomes of patients with atrial isomerism were found to be similar with those observed in high-income countries. Although an increased mortality rate was noted within the first year of life, focusing efforts on neonatal and infant care holds potential for improving overall outcomes.

Early and long-term outcomes following cardiac surgery for patients with heterotaxy syndrome

Objective

Heterotaxy syndrome is a complex multisystem abnormality historically associated with high morbidity and mortality. We sought to evaluate the early and long-term outcomes after cardiac surgery in heterotaxy syndrome.

Methods

This is a single-center retrospective review of patients with heterotaxy syndrome undergoing single-ventricle palliation or primary or staged biventricular repair from 1998 to 2018. Patients were stratified by single ventricle versus biventricular physiology, and the severity of atrioventricular valve regurgitation. Demographics, anatomic characteristics, and early and late outcomes, including the length of stay, mortality, and surgical or catheter reinterventions, were analyzed.

Results

Among 250 patients, 150 (60%) underwent biventricular repair. In-hospital mortality was 7.6% (n = 19). Median follow-up was 5.2 (range, 0-16) years. Among survivors to discharge, mortality was 19% (n = 44) and reintervention was 52% (n = 120). Patients with moderate/severe atrioventricular valve regurgitation were older (32 vs 16 months, P = .02), were more likely to experience adverse events during their index surgical admission (72% vs 46%, P < .001), and had longer in-hospital length of stay (20 vs 12 days, P = .009). Among patients with moderate to severe atrioventricular valve regurgitation, single-ventricle palliation is associated with a greater risk of unplanned reintervention compared with patients undergoing biventricular repair (hazard ratio, 2.13; CI, 1.10-4.12; P = .025).

Conclusions

There was no significant difference in early or late outcomes in single-ventricle versus biventricular repair strategies in heterotaxy. In the subgroup of patients with moderate/severe atrioventricular valve regurgitation, patients who underwent single-ventricle palliation were 2.5 times more likely to need a late reintervention compared with those undergoing biventricular repair.

Anatomy, embryology, and imaging of situs ambiguous with polysplenia and left IVC

The situs ambiguous or heterotaxy syndrome is a type of syndrome that involves multiple visceral abnormalities, vascular ones and associated with left isomerism. Malformation of gastroenterologic system includes polysplenia (segmented spleen or multiple splenules), agenesis (partial or complete) of the dorsal pancreas and anomalous of the inferior vena cava implantation. Here, we describe and show the anatomy of a patient with left side inferior vena cava, situs ambiguous (complete common mesentery), polysplenia, and short pancreas. We also discuss about the embryologic process and the implications of these anomalies during gynecologic, digestive, and liver surgeries.

LOF variants identifying candidate genes of laterality defects patients with congenital heart disease

Defects in laterality pattern can result in abnormal positioning of the internal organs during the early stages of embryogenesis, as manifested in heterotaxy syndrome and situs inversus, while laterality defects account for 3~7% of all congenital heart defects (CHDs). However, the pathogenic mechanism underlying most laterality defects remains unknown. In this study, we recruited 70 laterality defect patients with CHDs to identify candidate disease genes by exome sequencing. We then evaluated rare, loss-of-function (LOF) variants, identifying candidates by referring to previous literature. We chose TRIP11, DNHD1, CFAP74, and EGR4 as candidates from 776 LOF variants that met the initial screening criteria. After the variants-to-gene mapping, we performed function research on these candidate genes. The expression patterns and functions of these four candidate genes were studied by whole-mount in situ hybridization, gene knockdown, and gene rescue methods in zebrafish models. Among the four genes, trip11, dnhd1, and cfap74 morphant zebrafish displayed abnormalities in both cardiac looping and expression patterns of early signaling molecules, suggesting that these genes play important roles in the establishment of laterality patterns. Furthermore, we performed immunostaining and high-speed cilia video microscopy to investigate Kupffer's vesicle organogenesis and ciliogenesis of morphant zebrafish. Impairments of Kupffer's vesicle organogenesis or ciliogenesis were found in trip11, dnhd1, and cfap74 morphant zebrafish, which revealed the possible pathogenic mechanism of their LOF variants in laterality defects. These results highlight the importance of rare, LOF variants in identifying disease-related genes and identifying new roles for TRIP11, DNHD1, and CFAP74 in left-right patterning. Additionally, these findings are consistent with the complex genetics of laterality defects.

A multi-disciplinary, comprehensive approach to management of children with heterotaxy

Heterotaxy (HTX) is a rare condition of abnormal thoraco-abdominal organ arrangement across the left-right axis of the body. The pathogenesis of HTX includes a derangement of the complex signaling at the left-right organizer early in embryogenesis involving motile and non-motile cilia. It can be inherited as a single-gene disorder, a phenotypic feature of a known genetic syndrome or without any clear genetic etiology. Most patients with HTX have complex cardiovascular malformations requiring surgical intervention. Surgical risks are relatively high due to several serious comorbidities often seen in patients with HTX. Asplenia or functional hyposplenism significantly increase the risk for sepsis and therefore require antimicrobial prophylaxis and immediate medical attention with fever. Intestinal rotation abnormalities are common among patients with HTX, although volvulus is rare and surgical correction carries substantial risk. While routine screening for intestinal malrotation is not recommended, providers and families should promptly address symptoms concerning for volvulus and biliary atresia, another serious morbidity more common among patients with HTX. Many patients with HTX have chronic lung disease and should be screened for primary ciliary dyskinesia, a condition of respiratory cilia impairment leading to bronchiectasis. Mental health and neurodevelopmental conditions need to be carefully considered among this population of patients living with a substantial medical burden. Optimal care of children with HTX requires a cohesive team of primary care providers and experienced subspecialists collaborating to provide compassionate, standardized and evidence-based care. In this statement, subspecialty experts experienced in HTX care and research collaborated to provide expert- and evidence-based suggestions addressing the numerous medical issues affecting children living with HTX.

Prenatal diagnosis of hepatic interruption of the inferior vena cava with azygos/hemiazygos continuation without structural heart defects: A case series

OBJECTIVES

To describe fetal spectrum and echocardiographic characteristics of interrupted inferior vena cava (IIVC) with azygos/hemiazygous continuation without other structural heart defects and to evaluate its association with visceral heterotaxy and isomerism, extracardiac and genetic anomalies, and to review neonatal outcome.

METHODS

This was a retrospective study of 14 fetuses with a confirmed diagnosis of IIVC with normal intracardiac anatomy. The following variables were collected; indication for referral, gestational age at diagnosis; associated isomerism and visceral heterotaxy, heart rhythm, genetic and extracardiac abnormalities, and fetal/neonatal outcome.

RESULTS

Among 36 fetuses with IIVC, 14 cases (38.8%) had normal intracardiac anatomy. These IIVC cases correspond to 0.19% (14/7250) of all fetal cardiac examinations, and to 1.5% (14/922) of all cardiac abnormalities. Six patients had visceral abnormalities. Atrial appendage morphology was clearly depicted in three fetuses, both appendages were left. One fetus had bradyarrhythmia revealing atrial ectopic rhythm. Six fetuses did not have any concomitant cardiac or visceral abnormalities, therefore regarded as isolated. All babies were delivered at term with a good prognosis.

CONCLUSION

Our study has shown that almost half of the IIVC cases without intracardiac structural anomalies displayed other findings of isomerism while the other half was isolated benign vascular variant. Therefore, prenatal diagnosis of IIVC should prompt a comprehensive evaluation for cardiac, situs, and visceral anomalies. The outcome is favorable.

Impact of gastrointestinal comorbidities in patients with right and left atrial isomerism

BACKGROUND AND AIM

Heterotaxy syndrome, being right atrial isomerism (RAI) or left atrial isomerism (LAI), often presents with Congenital Heart Disease (CHD). Intestinal abnormalities, including malrotation are common. We assessed the spectrum of gut abnormalities and their impact on medium-term outcome in a cohort of patients with fetal and postnatal diagnoses of heterotaxy syndrome.

METHODS

We reviewed the cardiology records of heterotaxy syndrome patients from two centres, regarding the presence of CHD, time for cardiac intervention, presence of gastrointestinal abnormalities, and type/time of surgery. A questionnaire about gastrointestinal status was sent to patients <18 years old. Kaplan-Meier curves were derived for survival data and freedom from intervention.

RESULTS

Data were included for 182 patients (49 RAI and 133 LAI) of 247 identified. Questionnaires were sent to 77 families and 47 replied. CHD was present in all RAI and 61.7% of LAI cases. Thirty-eight patients had abdominal surgery (20.9%), similar for RAI and LAI (20.4% versus 21%, p> 0.99): Ladd procedure in 17 (44.7%), non-Ladd in 12 (31.5%), and both procedures in 9 (23.7%). Ten-year freedom from Ladd procedure for all was 86% for the whole cohort (RAI = 87%; LAI = 85%, p = 0.98). Freedom from any gastrointestinal surgery at 10 years was 79% for the whole cohort (RAI = 77%; LAI = 80%, p = 0.54). Ten-year freedom from cardiac surgery was 31% for the whole cohort (RAI = 6%; LAI = 43%, p < 0.0001).

CONCLUSIONS

In our cohort, one in five patients required abdominal surgery, mostly in their first year of life, similar for RAI and LAI. Between 1 and 10 years of follow-up, the impact of gastrointestinal abnormalities on outcome was minimal. Medium term survival was related to CHD.

A novel nonsense PKD1L1 variant cause heterotaxy syndrome with congenital asplenia in a Han Chinese patient

Heterotaxy syndrome is a very rare congenital disease, which is caused by the disorder of left-right asymmetry during visceral development. However, pathogenic genetic lesions are found in less than 20% of HS patients. In this cohort study, whole-exome sequencing was performed for 110 patients with situs inversus or situs ambiguous. We identified a novel nonsense variant in PKD1L1(c.1387 C > T; p.463Gln*) in a Chinese patient with heterotaxy syndrome and congenital asplenia. This homozygous variant caused the domain of PKD1L1 complete absence. To our knowledge, this novel variant is the first phenotype of congenital asplenia found in patients with PKD1L1 variants, and the first PKD1L1 variant found in China. Our findings expand the spectrum of PKD1L1 variants and provide support for PKD1L1 variant and congenital asplenia, and the critical role of PKD1L1 during left-right patterning in the Han Chinese population.

Heterotaxy syndrome: Prenatal diagnosis, concomitant malformations and outcomes

OBJECTIVE

The aim of this study is to define cardiac and extracardiac malformations in fetuses with heterotaxy syndrome and to determine perinatal and childhood prognosis.

METHODS

In this retrospective study, fetuses diagnosed with heterotaxy syndrome on antenatal ultrasonography in a tertiary center between January 2014 and January 2021 were analyzed. Fetuses with heterotaxy syndrome were grouped as right atrial isomerism (RAI) and left atrial isomerism (LAI).

RESULTS

A total of 62 fetuses, 32 (51.6%) with RAI and 30 (48.4%) with LAI, were included in the study. Extracardiac anomaly was detected in 25% of fetuses with RAI and 44% of fetuses with LAI (p = 0.13). Patients with univentricular repair had a higher childhood mortality than patients with biventricular repair (p = 0.031). The presence of conotruncal anomaly was an independent factor affecting mortality (HR = 5.09, CI 95% 1.09-23.71, p = 0.039).

CONCLUSION

Hydrops fetalis, univentricular physiology and conotruncal anomalies are associated with poor outcomes in heterotaxy syndrome. The severity of the cardiac malformation is the main determinant of the outcomes. The presence of extracardiac malformations is associated with increased morbidity and mortality.

Multimodality imaging of developmental splenic anomalies: tips and pitfalls

Anomalies in number and location may occur during splenic development. This review aims to offer a brief overview of splenic function and embryology and a detailed account of the imaging appearances using different imaging techniques of the normal spleen and various congenital splenic anomalies including (1) abnormal viscero-atrial situs, (2) splenogonadal fusion, (3) intrapancreatic accessory spleen, (4) wandering spleen, and (5) splenosis. Emphasis is placed on the salient features that help radiologists recognise important associations (e.g., asplenia/polysplenia in situs abnormalities), avoid diagnostic pitfalls (e.g., mistaking intrapancreatic accessory spleen as pancreatic neoplasms), and potential complications (e.g., acute torsion in wandering spleen). The correct identification of the said anomalies from more sinister causes, such as malignancies, are essential, where early intervention is necessary.

Discordant Post-natal Patterns in Fetuses With Heterotaxy Syndrome: A Retrospective Single-Centre Series on Outcome After Fetal Diagnosis

OBJECTIVE

Cardiac and extra-cardiac anomalies in 46 pre-natally diagnosed cases of heterotaxy were compared to post-natal anatomical patterns in order to reveal discordant findings. Second, the outcome of these fetuses was evaluated.

METHODS

Fetuses with heterotaxy, diagnosed in a tertiary referral centre, were analysed retrospectively. Based on the foetal abdominal situs view, right atrial isomerism (RAI) and left atrial isomerism (LAI) were defined as foetal sub-types. Post-natally, discordant anatomical patterns for broncho-pulmonary branching, atrial appendage morphology, and splenic status were further clarified with CT scans. In summary, the spectrum of pre-natally and post-natally detected cardiac and extra-cardiac anomalies is systematically reviewed. Necessary surgical interventions and mid-long-term outcomes were compared between the two sub-types in surviving infants.

RESULTS

A total of 46 fetuses with heterotaxy were included; LAI was diagnosed in 29 (63%) fetuses and RAI was diagnosed in 17 (37%) fetuses. Extra-cardiac anomalies were noted in 35% of fetuses. Seven out of the 29 fetuses (24%) with LAI had atrio-ventricular block (AVB) and four of these cases presented with hydrops. Twenty nine out of the 46 participating fetuses (63%) were live births, with 62% in the LAI group and 65% in the RAI group. Five fetuses were lost to follow-up. At the age of 1 year, the overall survival of live births [estimate (95% CI)] was 67% (48; 92%) in patients with LAI and 55% (32; 94%) in patients with RAI. At the age of 5 years, the estimates were 67% (48; 92%) in the LAI group and 46% (24-87%) in the RAI group. The median survival (first quartile; third quartile) was 11.1 (0.1; 14) years for patients with LAI and 1.3 (0.09; NA) years for patients with RAI. Of 17 children who had undergone cardiac surgery, five (29%) children achieved a bi-ventricular repair and 12 (70%) children achieved a uni-ventricular palliation. Three were primarily palliated, but converted to bi-ventricular thereafter. Foetal subtype definition of heterotaxy based on the abdominal situs and post-natal thoracic imaging studies showed a discordant pattern of broncho-pulmonary branching and atrial appendage anatomy in 40% of our live-born children.

CONCLUSION

Heterotaxy is a rare and complex condition with significant morbidity and mortality related to severe cardiac and extra-cardiac associations. Accurate pre-natal diagnosis can help identify the fetuses at risk and allow for timely intervention in a multi-disciplinary setting. Further studies are warranted to shed light on the exact sub-type definition in fetuses with heterotaxy and the presence of discordant post-natal patterns.

A Rare Case of Recurrent Pneumonia in Heterotaxy Syndrome, Polysplenia/Left Isomerism

Heterotaxy syndrome (HS) or situs ambiguous refers to the abnormal arrangement of viscera across the body axis, and abnormalities arise depending on the isomerism of the right or left atrial appendage. The cause remains unexplained and is attributed to a combination of genetic mutations and environmental factors. It is a rare condition and may remain undiagnosed for a long time. In this report, we aim to highlight an unusual presentation and aggravation of an infection due to the underlying isomerism of the left atrial appendage. We discuss the case of a female patient who presented with symptoms of fever and cough. The patient underwent prolonged antibiotic treatment, and her recovery was slow. The presence of bilobed lungs, vertical left-bronchus, and polysplenia on CT scan explained the left-sided aspiration pneumonia. The hypofunctioning spleen (polysplenia) caused her to have a weak immunological response, necessitating prolonged antibiotic use. She was followed up over time and had a recurrence of pneumonia within a few months. The condition is associated with high morbidity and mortality, and the role of early diagnosis and reporting to prevent complications is paramount. The recurrent pneumonia observed in the patient also raises questions related to long-term antibiotic use and immunization in the case of polysplenia in this patient population.

Characterization of phenotypic spectrum of fetal heterotaxy syndrome by combining ultrasound and magnetic resonance imaging

OBJECTIVE

Heterotaxy or isomerism of the atrial appendages is a congenital disorder with variable presentation, associated with both cardiac and non-cardiac anomalies, which may have a serious impact on fetal outcome. The aim of this exploratory study was to assess the value of fetal magnetic resonance imaging (MRI), as a complementary tool to ultrasound, for describing the morphological spectrum encountered in heterotaxy.

METHODS

This retrospective study included 27 fetuses that underwent fetal MRI following prenatal suspicion of heterotaxy on ultrasound from 1998 to 2019 in a tertiary referral center. Heterotaxy was classified as left atrial isomerism (LAI) or right atrial isomerism (RAI) based on fetal echocardiography (FE) examination. In addition to routine prenatal ultrasound, fetal MRI was offered routinely to enhance the diagnosis of non-cardiac anomalies, which might have been missed on ultrasound. Prenatal findings on ultrasound, FE and MRI were reviewed systematically and compared with those of postnatal imaging and autopsy reports.

RESULTS

Twenty-seven fetuses with heterotaxy and cardiovascular pathology, of which 19 (70%) had LAI and eight (30%) had RAI, were included. Seven (7/19 (37%)) fetuses with LAI had normal intracardiac anatomy, whereas all fetuses with RAI had a cardiac malformation. All 27 fetuses had non-cardiac anomalies on fetal MRI, including situs and splenic anomalies. In 12/19 (63%) fetuses with LAI, a specific abnormal configuration of the liver was observed on MRI. In three fetuses, fetal MRI revealed signs of total anomalous pulmonary venous connection obstruction. An abnormal bronchial tree pattern was suspected on prenatal MRI in 6/19 (32%) fetuses with LAI and 3/8 (38%) fetuses with RAI.

CONCLUSIONS

Visualization on MRI of non-cardiac anomalies in fetuses with suspected heterotaxy is feasible and can assist the complex diagnosis of this condition, despite its limitations. This modality potentially enables differentiation of less severe cases from more complex ones, which may have a poorer prognosis. Fetal MRI can assist in prenatal counseling and planning postnatal management. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Novel MYO1D Missense Variant Identified Through Whole Exome Sequencing and Computational Biology Analysis Expands the Spectrum of Causal Genes of Laterality Defects

Laterality defects (LDs) or asymmetrically positioned organs are a group of rare developmental disorders caused by environmental and/or genetic factors. However, the exact molecular pathophysiology of LD is not yet fully characterised. In this context, studying Arab population presents an ideal opportunity to discover the novel molecular basis of diseases owing to the high rate of consanguinity and genetic disorders. Therefore, in the present study, we studied the molecular basis of LD in Arab patients, using next-generation sequencing method. We discovered an extremely rare novel missense variant in MYO1D gene (Pro765Ser) presenting with visceral heterotaxy and left isomerism with polysplenia syndrome. The proband in this index family has inherited this homozygous variant from her heterozygous parents following the autosomal recessive pattern. This is the first report to show MYO1D genetic variant causing left-right axis defects in humans, besides previous known evidence from zebrafish, frog and Drosophila models. Moreover, our multilevel bioinformatics-based structural (protein variant structural modelling, divergence, and stability) analysis has suggested that Ser765 causes minor structural drifts and stability changes, potentially affecting the biophysical and functional properties of MYO1D protein like calmodulin binding and microfilament motor activities. Functional bioinformatics analysis has shown that MYO1D is ubiquitously expressed across several human tissues and is reported to induce severe phenotypes in knockout mouse models. In conclusion, our findings show the expanded genetic spectrum of LD, which could potentially pave way for the novel drug target identification and development of personalised medicine for high-risk families.

Predicting Cardiac Anatomy, Physiology, and Surgical Management Based on Fetal Echocardiography in Heterotaxy Syndrome

OBJECTIVE

 Heterotaxy syndrome (HS) is often associated with complex congenital heart disease (CHD). While fetal echocardiography (FE) permits accurate prenatal identification of most CHD, the high level of disease complexity in HS may pose challenges in predicting postnatal findings and outcomes. This study aimed to define the accuracy of FE in predicting postnatal anatomy, physiology, and surgical management of CHD in the setting of HS.

STUDY DESIGN

 Retrospective single-center cohort study including all patients with a prenatal diagnosis of HS from 2003 to 2018. Anatomic diagnoses from FE reports were compared with postnatal echocardiogram, catheterization, and operative reports. Prenatal predictions were compared with postnatal outcomes with a focus on ductal dependence, time to first intervention (immediate, neonatal period, 1-6 months, or older than 6 months), and surgical approach (single or biventricular).

RESULTS

 There were 102 pregnancies with fetal HS resulting in 21 terminations, 5 fetal losses, and 76 live births. Of the live births, 55 had significant CHD and available postnatal data for review. Among this group, survival to 1 year was 62% and was no different comparing single versus biventricular surgical approach. FE diagnostic accuracy varied by anatomic feature and was the lowest for diagnosis of venous anatomy. Determination of postnatal care was most accurate for predicting single versus biventricular surgical approach (91%), followed by ductal dependence (75%). Accuracy for predicting time to first intervention was the lowest at 69%. The most common reason for an incorrect prediction was difficulty in assessing the severity of pulmonary stenosis.

CONCLUSION

 FE permits accurate predictions regarding surgical approach. Characterizing systemic and pulmonary veins is challenging, as is predicting ductal dependence and time to first intervention. These data suggest that despite the high diagnostic accuracy of CHD in HS, a circumspect approach may be reasonable with regard to predicting some anatomic details and postnatal management decisions.

KEY POINTS

· In HS, FE was most accurate for intracardiac anatomy.. · Diagnostic accuracy of venous anatomy was less reliable.. · Predicting surgical approach (single ventricle vs. biventricular) was highly accurate.. · Predicting ductal dependence and time-to-intervention were more challenging in some instances..

The multisystem nature of isomerism: left isomerism complicated by Abernethy malformation and portopulmonary hypertension

Isomerism, also referred to as "heterotaxy" is a complex set of anatomic and functional perturbations. One of the most obvious manifestations of isomerism is the disturbance of organ arrangement, such that the thoracic organs are no longer asymmetric on the left and right. We report the case of a 14-year-old female in whom exercise-induced dyspnea led to a late diagnosis of left isomerism complicated by Abernethy malformation and portopulmonary hypertension. A comprehensive evaluation revealed two anatomic left lungs and hyparterial bronchi, bilateral left atria, an interrupted inferior caval vein with azygos continuation, multiple spleens, sinus node dysfunction, hepatic hypertrophy with focal nodular hyperplasia, and absence of the portal vein. Pulmonary vasodilator therapy was initiated resulting in clinical improvement. This case exhibits unique features including a late diagnosis of isomerism with Abernethy malformation and portopulmonary hypertension. The patient's presentation, medical workup, and future treatment emphasise the importance of multidisciplinary care in children with complex multisystem disease. We review the multiple cardiac and extracardiac manifestations of isomerism.

Twin atrioventricular nodes, arrhythmias, and survival in pediatric and adult patients with heterotaxy syndrome

BACKGROUND

Heterotaxy syndrome is likely to involve arrhythmias from associated conduction system abnormalities, which are distinct in different subtypes of isomerism and may change further after interventions and remodeling.

OBJECTIVE

The purpose of this study was to understand the risk of arrhythmias and its relation to isomerism subtypes.

METHODS

Patients diagnosed between 1980 and 2019 as having heterotaxy syndrome were enrolled and grouped as right atrial isomerism (RAI), left atrial isomerism (LAI), or indeterminate isomerism.

RESULTS

Of the 366 patients enrolled, 326 (89.1%) had RAI, 35 (9.6%) LAI, and 5 (1.4%) indeterminate isomerism; 71 (19.4%) patients were adults. Arrhythmias occurred in 37.2% of patients (109 supraventricular tachycardia [SVT], 8 atrial fibrillation/flutter, 12 ventricular tachycardia, and 14 paced bradycardia). Freedom from arrhythmias by the age of 1, 5, 10, 20, and 40 years was 0.849, 0.680, 0.550, 0.413, and 0.053, respectively. Twin atrioventricular nodes were identified in 51.5% of patients with RAI, 8.7% of patients with LAI, and 40.0% of patients with indeterminate isomerism and were the key predictors of SVT. Indeterminate isomerism was also a risk factor for SVT. Other forms of tachycardia appeared relatively late. Sinus bradycardia with junctional rhythm was common in LAI (48.7%) and less in indeterminate isomerism (20.0%), with none occurring in RAI. Only in patients with RAI who showed the poorest survival, ventricular tachycardia worsened the long-term survival.

CONCLUSION

RAI was the predominant subtype of heterotaxy in this cohort. Collectively, the median RAI/LAI ratio was 0.731 and 5.450 in Western and East Asian studies, respectively. Arrhythmias, tachycardia, or paced bradycardia were common, but the spectrum was distinct among subtypes.

Changes in Prognosis of Heterotaxy Syndrome Over Time

BACKGROUND

Long-term outcomes in heterotaxy syndrome (HS) are poorly described. Some reports suggest improved survival in the recent era, whereas others do not. We sought to describe long-term outcomes and assess whether outcomes have changed over time.

METHODS

Patients with HS born between 1985 and 2014 who had cardiac care (except initial palliation) at our institution were divided into 4 birth eras and survival over time was compared. Independent risk factors for mortality were identified by using Cox proportional hazards regression. In patients who underwent surgery, association between surgical pathway (univentricular versus biventricular repair) and mortality after adjusting for baseline confounders was evaluated. A risk stratification model was created by using classification and regression analysis.

RESULTS

Among 264 patients, 118 (44.7%) had asplenia and 146 (55.3%) had polysplenia syndrome. Overall mortality was 40.2% (n = 106), with median follow-up of 10.2 years (longest 31.5 years). In multivariable analysis, pulmonary vein stenosis, coarctation, univentricular circulation, asplenia phenotype, and at least mild atrioventricular valve regurgitation at presentation were associated with mortality, whereas birth era was not. Among patients who underwent surgery, univentricular repair remained associated with mortality after adjustment. In classification and regression analysis, patients with biventricular circulation (especially those with polysplenia) had lower mortality than those with univentricular circulation.

CONCLUSIONS

In this large retrospective study of HS, outcomes remain poor and have not improved since the early 1990s. We identified risks factors associated with earlier mortality and found that those with univentricular circulation and totally anomalous pulmonary venous connection had the worst prognosis. Survival was higher in those with biventricular circulation.

Polysplenia syndrome with complex heart disease and jejunal atresia with malrotation in neonate: A case report

Polysplenia is heterotaxy syndrome or bilateral left-sidedness. We report a case of polysplenia syndrome in order to draw attention to this rare syndrome that must be excluded in an infant presenting with congenital heart disease and intestinal malformations.

Fetal cardiac abnormalities: Genetic etiologies to be considered

Congenital heart diseases are a common prenatal finding. The prenatal identification of an associated genetic syndrome or a major extracardiac anomaly helps to understand the etiopathogenic diagnosis. Besides, it also assesses the prognosis, management, and familial recurrence risk while strongly influences parental decision to choose termination of pregnancy or postnatal care. This review article describes the most common genetic diagnoses associated with a prenatal finding of a congenital heart disease and a suggested diagnostic process.

Characteristics and outcomes of fetuses with laterality defects are the current outcomes better? A single center study

Objective: To analyze the more recent outcomes of fetuses with different laterality defects.Material and methods: Out of 1508 fetuses with congenital heart disease (CHD) diagnosed by echocardiography between January 1995 and December 2015, 94 (6.3%) presented abnormal visceroatrial situs: 42 till December 2002 (group 1, analyzed retrospectively) and 52 since then until December 2015 (group 2, analyzed prospectively). Twenty-one had left isomerism (Lisom), 22 right isomerism (Risom), 16 situs inversus- dextrocardia (SVI-dx), 5 situs inversus- levocardia (SVI-levo), and 30 situs solitus-dextrocardia (SSol-dx).Results: Seventy-six cases (81%) had CHD, more frequently complex atrioventricular defect. Eighteen cases showed normal heart: half of subgroups SVI-dx and SVI-levo, a third of SSol-dx. Postoperative mortality in continuing pregnancy in group 2 was 43.7 versus 40% in group 1, lower in SVs-dx (0 versus 50%) and Lisom (33.3 versus 66.7%), worse in Risom (71.4 versus 25%). Total mortality in group 2 was 48.3 versus 55% in group 1, better in Ssol-dx (37.5 versus 50%) and in Lisom (27.4 versus 71.4%). In isolated forms all but one case are alive.Conclusions: Our fetal cases presented a relevant mortality in both periods. The outcomes were slightly better in a more recent era in SSol and Lisom.What is known about this topic?Out of laterality defects, the heterotaxies (i.e. left and right isomerism) are known to be associated to a relevant mortality in fetal and neonatal cases.Heterotaxies have a variable position of the heart, but some authors evaluated only those with dextrocardia in their studies on different laterality defects.Controversial data are presented in the literature for the outcomes of fetuses with laterality defects. Many large studies analyzed the data of a very long time period in which it is opinable to compare the results of the treatment, because of a recent improved management and surgical techniques.What does this study add?Our study presents an experience of a single center with cases of different types of laterality defects observed during a routine fetal echocardiography, not only heterotaxies.The knowledge of different laterality defects and of their characteristics (association with cardiac and extracardiac anomalies or with normal heart) is useful for the prenatal counseling.We compare the postoperative and total mortality in more recent period (since 2003) with respect to the previous era (1995-2002).

Genetic architecture of laterality defects revealed by whole exome sequencing

Aberrant left-right patterning in the developing human embryo can lead to a broad spectrum of congenital malformations. The causes of most laterality defects are not known, with variants in established genes accounting for <20% of cases. We sought to characterize the genetic spectrum of these conditions by performing whole-exome sequencing of 323 unrelated laterality cases. We investigated the role of rare, predicted-damaging variation in 1726 putative laterality candidate genes derived from model organisms, pathway analyses, and human phenotypes. We also evaluated the contribution of homo/hemizygous exon deletions and gene-based burden of rare variation. A total of 28 candidate variants (26 rare predicted-damaging variants and 2 hemizygous deletions) were identified, including variants in genes known to cause heterotaxy and primary ciliary dyskinesia (ACVR2B, NODAL, ZIC3, DNAI1, DNAH5, HYDIN, MMP21), and genes without a human phenotype association, but with prior evidence for a role in embryonic laterality or cardiac development. Sanger validation of the latter variants in probands and their parents revealed no de novo variants, but apparent transmitted heterozygous (ROCK2, ISL1, SMAD2), and hemizygous (RAI2, RIPPLY1) variant patterns. Collectively, these variants account for 7.1% of our study subjects. We also observe evidence for an excess burden of rare, predicted loss-of-function variation in PXDNL and BMS1- two genes relevant to the broader laterality phenotype. These findings highlight potential new genes in the development of laterality defects, and suggest extensive locus heterogeneity and complex genetic models in this class of birth defects.

Effect of Prenatal Laterality Disturbance and Its Accompanying Anomalies on Survival

In this retrospective, observational study of fetuses diagnosed with a laterality disturbance we describe the findings and outcome of fetuses diagnosed between 1980 and 2017 at a tertiary fetal-pediatric cardiology unit. In addition we sought to identify features which impact on outcome. Left atrial isomerism (LAI) was diagnosed in 177 babies and right atrial isomerism (RAI) in 100. Major structural heart disease was present in all cases of RAI and 91% with LAI. Complete heart block (CHB) was present in 40% of LAI. For surviving live-born infants a biventricular circulation was feasible in 3% with RAI and 43% with LAI. The median survival for live-borns with LAI was 13 months (range 0 to 272 months) and for RAI 19 months (range 0.3 to 292 months). The median postnatal survival with CHB was 0.2 months (range 0 to 228 months) compared to 44 months with sinus rhythm (interquartile range 0 to 272 months; p <0.0001). The 5-year survival was 1980 to 1989, RAI 0%, LAI 0%; 1990 to 1999, RAI 62%, LAI 54%; 2000 to 2009, RAI 59%, LAI 53%; 2010 to 2017, RAI 67%, LAI 75% by era. The rate of intrauterine death remained. Risk factors for death/transplantation for RAI were total anomalous pulmonary venous drainage, left heart obstruction (hazard ratios 2.7, p = 0.048; 5.8, p = 0.03) and for LAI: CHB, anomalous pulmonary venous drainage and right heart obstruction (hazard ratios 11.5, 6.2, 3.8, respectively (p = 0.008, p = 0.003, p <0.001)). In conclusion, laterality disturbances represent a complex form of congenital heart disease and although survival is improved, it remains poor especially in the presence of anomalous pulmonary venous drainage, stenotic and/or atretic valves, and CHB.

Outcome of prenatally diagnosed fetal heterotaxy: systematic review and meta-analysis

OBJECTIVES

The main aim of this systematic review was to evaluate the prevalence and type of associated anomalies in fetuses with heterotaxy diagnosed prenatally on ultrasound; the perinatal outcome of these fetuses was also studied.

METHODS

An electronic search of MEDLINE, EMBASE and CINAHL databases was performed. Only studies reporting the prenatal diagnosis of isomerism were included. Outcomes observed included associated cardiac and extracardiac anomalies, fetal arrhythmia, abnormal karyotype, type of surgical repair and perinatal mortality. The analysis was stratified according to the type of heterotaxy syndrome (left (LAI) or right (RAI) atrial isomerism). Meta-analyses of proportions were used to combine data. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies.

RESULTS

Sixteen studies (647 fetuses) were included in the analysis. Atrioventricular septal defect was the most common associated major cardiac anomaly found both in fetuses with LAI (pooled proportion (PP), 59.3% (95% CI, 44.0-73.7%)), with obstructive lesions of the right outflow tract occurring in 35.5% of these cases, and in fetuses with RAI (PP, 72.9% (95% CI, 60.4-83.7%)). Fetal arrhythmias occurred in 36.7% (95% CI, 26.9-47.2%) of cases with LAI and were mainly represented by complete atrioventricular block, while this finding was uncommon in cases with RAI (PP, 1.3% (95% CI, 0.2-3.2%)). Abnormal stomach and liver position were found, respectively, in 59.4% (95% CI, 38.1-79.0%) and 32.5% (95% CI, 11.9-57.6%) of cases with LAI, and in 54.5% (95% CI, 38.5-70.1%) and 45.9% (95% CI, 11.3-83.0%) of cases with RAI, while intestinal malrotation was detected in 14.2% (95% CI, 2.5-33.1%) of LAI and 27.1% (95% CI, 7.9-52.0%) of RAI cases. Hydrops developed in 11.8% (95% CI, 2.9-25.6%) of fetuses diagnosed prenatally with LAI. Biventricular repair was accomplished in 78.2% (95% CI, 64.3-89.4%) of cases with LAI, while univentricular repair or palliation was needed in 17.0% (95% CI, 9.7-25.9%); death during or after surgery occurred in 26.8% (95% CI, 4.6-58.7%) of LAI cases. Most children with RAI had univentricular repair and 27.8% (95% CI, 15.5-42.1%) died during or after surgery.

CONCLUSIONS

Fetal heterotaxy is associated with a high prevalence of cardiac and extracardiac anomalies. Approximately one quarter of fetuses with heterotaxy died during or after surgery. Abnormal heart rhythm, especially heart block, is common in fetuses with LAI, while this finding is uncommon in RAI. Biventricular repair was common in LAI while univentricular repair was required in the majority of children affected by RAI. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal Findings in Left Atrial Isomerism and an Overview of Heterotaxy Syndrome

Heterotaxy syndrome is a rare, complex disorder involving structural cardiac defects in combination with symmetrical development of abdominal viscera that are normally asymmetrical organs. The vast assortment of cardiac manifestations with accompanying abdominal visceral variations determines the prognosis of heterotaxy syndrome. This case study provides an example of the management of this disease, which is unique to the patient. This is a case report of heterotaxy syndrome diagnosed in utero at 29 weeks and 4 days.

Stillbirth and neonatal mortality in pregnancies complicated by major congenital anomalies: Findings from a large European cohort

OBJECTIVE

To provide prognostic information to help parents to reach an informed decision about termination or continuation of the pregnancy and to shape peripartum policy based on a large European cohort.

METHOD

Thirteen registries from the European Surveillance of Congenital Anomalies (EUROCAT) network contributed data from January 1, 1998, to December 31, 2011. Terminations for fetal anomalies were excluded. Chromosomal anomalies, syndromes and isolated anomaly groups were distinguished according to EUROCAT guidelines. Perinatal mortality, stillbirths, and early and late neonatal mortality rates (NMRs) were analyzed by anomaly group and gestational age.

RESULTS

Among 73 337 cases, perinatal mortality associated with congenital anomaly was 1.27 per 1000 births (95% confidence interval, 1.23-1.31). Average stillbirth rate was 2.68% (range 0%-51.2%). Early and late NMR were 2.75% (range 0%-46.7%) and 0.97% (range 0%-17.9%), respectively. Chromosomal anomalies and syndromes, and most isolated anomalies, had significant differences regarding timing of fetal demise compared to the general population. Chromosomal and central nervous system anomalies had higher term stillbirth rates.

CONCLUSIONS

We found relevant differences between anomalies regarding rates of stillbirth, NMR, and timing by gestational age. Our data can help parents to decide about their unborn child with a congenital anomaly and help inform maternal-fetal medicine specialists regarding peripartum management.

Prenatal diagnosis of biliary atresia: A case series

BACKGROUND

Biliary atresia is a progressive disease presenting with jaundice, and is the most common indication for liver transplantation in the pediatric population. Prenatal series have yielded conflicting results concerning a possible association between BA and prenatal nonvisualization of the gallbladder.

AIMS

This retrospective case series was performed to assess the association between biliary atresia, prenatal nonvisualization of the gallbladder and other sonographic signs.

STUDY DESIGN/SUBJECTS

We identified biliary atresia patients who underwent a Kasai procedure by a single pediatric surgeon and/or follow up by a single pediatric gastroenterologist. Axial plane images and/or video recordings were scrutinized for sonographic signs of biliary atresia on the second trimester anomaly scan.

OUTCOME MEASURES

Proportion of biliary atresia cases with prenatal sonographic signs.

RESULTS

Twenty five charts of children with biliary and high quality prenatal images were retrieved. 6/25 (24%) of cases analyzed had prenatal nonvisualization of the gallbladder or a small gallbladder on the prenatal scan. Two cases had biliary atresia splenic malformation syndrome. None of the cases had additional sonographic markers of biliary atresia.

CONCLUSIONS

Our study suggests that in addition to the well-established embryonic and cystic forms, an additional type can be suspected prenatally, which is characterized by prenatal nonvisualization of the gallbladder in the second trimester. This provides additional evidence that some cases of BA are of fetal rather than perinatal onset and may have important implications for prenatal diagnosis, for counseling and for research of the disease's etiology and pathophysiology.

Fetal Situs, Isomerism, Heterotaxy Syndrome: Diagnostic Evaluation and Implication for Postnatal Management

OPINION STATEMENT

A hallmark of vertebrate anatomy is asymmetry of structures, especially internal organs, on the left and right side of the body. Heterotaxy syndrome is the combination of correct-sided, and incorrect-sided organs. The establishment of the left-right axis is an early event in vertebrate embryogenesis. Failure to establish this axis has numerous consequences for later development and can result in a wide range of potential defects. Congenital heart disease is among the more frequent and serious problems. Heterotaxy syndrome is diagnosed prenatally with increasing frequency due to improved screening practices. The key to proper management of fetal heterotaxy syndrome is reliable determination of left and right in the fetus, a thorough understanding of associated defects and comprehensive imaging.

Predictors of poor outcome among children with heterotaxy syndrome: a retrospective review

Objective

To determine predictors of poor outcome in patients with heterotaxy syndrome.

Methods

A retrospective review of children with heterotaxy syndrome, in a single tertiary paediatric cardiology centre, was conducted between 1 January 1997 and 1 January 2014 to determine predictors of poor outcome. Poor outcome was defined as death, cardiac transplantation or New York Heart Association (NYHA) functional class III or IV.

Results

There were 35 patients diagnosed with heterotaxy syndrome, 17 of whom were diagnosed antenatally. 22 patients had right atrial isomerism and 13 had left atrial isomerism. The median age of postnatal diagnosis was 2.5 days old (1 day to 19 months). 12 patients had a poor outcome; 6 patients died, 1 underwent cardiac transplantation and 5 had an NYHA functional class of >III. 5 patients had a biventricular repair and the remaining 30 had a univentricular repair. Type of atrial isomerism, univentricular or biventricular anatomy, severity of atrioventricular valve regurgitation or ventricular dysfunction, obstructed pulmonary venous return, occurrence of arrhythmia and presence of pulmonary atresia did not predict poor outcome. Fetal diagnosis also did not confer a survival advantage. The median duration of follow-up in this cohort was 65 months (2 days to 16.8 years).

Conclusions

Survival for patients with heterotaxy syndrome was 83% over a median follow-up of 65 months. 34% of patients had a poor outcome. None of the variables studied were predictive of death, transplantation or NYHA classification III or IV.

Impact of Era, Type of Isomerism, and Ventricular Morphology on Survival in Heterotaxy: Implications for Therapeutic Management

BACKGROUND

Heterotaxy has been demonstrated to reduce survival. There are several different subgroups of patients, however, and no single study has had a large number of patients and analyzed survival across the different subgroups such as patients born in different eras, patients with right and left isomerism, and patients with biventricular or functionally univentricular hearts. This study pools previously reported data from Kaplan-Meier curves and performs such subgroup analysis.

METHODS

A systematic review of the literature was performed to identify studies reporting survival of patients with the so-called "heterotaxy" by means of Kaplan-Meier survival curves. Data were extracted from these survival curves and then pooled together. A polynomial regression was then used to generate a pooled survival curve. This was done for all patients, those born in a more recent era, those with right and left isomerism, and those with biventricular or functionally univentricular hearts.

RESULTS

Those born in the more recent era (after 2000) had increased survival compared to the overall cohort. Those with left isomerism tended to have a survival benefit compared to those with right isomerism until about 16 years of age, beyond which those with right isomerism developed a survival benefit. Those with biventricular hearts had a survival benefit compared to those with left isomerism.

CONCLUSION

Survival in the so-called heterotaxy syndrome is based on several factors, which include era of birth, sidedness of isomerism, and whether the heart is biventricular or functionally univentricular.

Utility of fetal magnetic resonance imaging in assessing the fetus with cardiac malposition

OBJECTIVE

Abnormal cardiac axis and/or malposition prompts evaluation of congenital heart disease; however, etiology may be difficult to clarify using obstetrical ultrasound or fetal echocardiography (echo) alone. We aimed to use fetal magnetic resonance imaging (MRI) as a complementary tool to identify causes of cardiac malposition.

METHODS

Review of fetuses diagnosed with cardiac malposition by fetal ultrasound and echo was performed. Etiology was classified as either because of heterotaxy syndrome or extracardiac masses. Reclassification was then performed with fetal MRI findings. Results were compared with postnatal diagnoses.

RESULTS

Forty-two fetuses were identified as having abnormal cardiac axis and/or malposition. Twenty three of 42 cases (55%) had extracardiac anomalies, while 19 (45%) were because of heterotaxy. Twelve of 42 (29%) cases were reassigned by fetal MRI (five in heterotaxy group and seven in the lung anomaly group). Four cases (33%) had both cardiac disease and extracardiac masses, not previously recognized. Fetal MRI clarified heterotaxy subtype or removed heterotaxy diagnosis in five (26%) patients. Fetal MRI findings were confirmed in 8 of these 12 cases postnatally.

CONCLUSION

Fetal MRI is a useful complementary tool to define etiology of cardiac malposition in complex cases for informative prenatal counseling and planning. © 2016 John Wiley & Sons, Ltd.

Screening and Treatment of Intestinal Rotational Abnormalities in Heterotaxy: A Systematic Review and Meta-Analysis

OBJECTIVE

To assess the role of screening and prophylactic surgery for intestinal rotational abnormalities (IRAs) in asymptomatic patients with heterotaxy.

STUDY DESIGN

PubMed, Embase, and Cinahl were searched electronically to determine the overall incidence of IRAs in heterotaxy; the detection rate of IRAs associated with screening; the incidence of midgut volvulus in patients without screening; and the incidence of morbidity and mortality after prophylactic and emergency Ladd procedures. Relevant data were computed with a meta-analysis of proportions. Between-study heterogeneity was assessed with the I(2) statistic.

RESULTS

From 276 papers identified, 24 studies with a total of 1433 patients with heterotaxy were included for systematic review. No randomized study was identified. True incidence of IRA in heterotaxy could not be ascertained through meta-analysis. In patients who underwent screening, the incidence of IRA was 58%. Acute midgut volvulus occurred in 5.8% of those who did not undergo screening. Postoperative mortality after Ladd procedure mainly was associated with cardiac insufficiency, and overall it was significantly greater in the emergency group compared with the prophylactic group (18% vs 5.6%). The complication rate also was greater in case of emergency vs prophylactic abdominal surgery (27% vs 16%); adhesional small bowel obstruction was the most common complication overall (6%).

CONCLUSION

The screen-detected incidences of IRA and acute midgut volvulus were significantly greater in heterotaxy than the normal population. Prophylactic Ladd procedure was associated with less morbidity and mortality compared with emergency surgery. A long-term prospective randomized trial is needed to define the indication for screening and prophylactic treatment of IRA in heterotaxy.

Extracardiac anomalies in prenatally diagnosed heterotaxy syndrome

OBJECTIVE

To assess the incidence and impact of extracardiac anomalies on the prognosis of fetuses with heterotaxy syndrome.

METHODS

All fetuses diagnosed with heterotaxy syndrome by three experienced examiners over a period of 14 years (1999-2013) were reviewed retrospectively.

RESULTS

In total, 165 fetuses with heterotaxy syndrome were diagnosed in the study period. One hundred and fifty (90.9%) had cardiac defects; extracardiac anomalies that did not involve the spleen were present in 26/165 (15.8%) cases. Of the total study cohort, termination of pregnancy was performed in 49 (29.7%) cases, intrauterine death occurred in 11 (6.7%), postnatal death occurred in 38 (23.0%) and 67 (40.6%) were alive at the latest follow-up, resulting in a total perinatal and pediatric mortality of 59.4%. Among the 105 liveborn neonates, 15 (14.3%) had extracardiac anomalies with significant impact on the postnatal course: one neonate died following repair of an encephalocele, six had successful treatment for various types of intestinal malrotation and/or atresia and one underwent hiatal hernia repair; the remaining seven had biliary atresia, of which five died and the two survivors are awaiting liver transplantation. The status of the spleen was assessed in 93/105 liveborn children and was found to be abnormal in 84/93 (90.3%). There were three cases of lethal sepsis, all associated with asplenia. Of the 38 postnatal deaths, 29 (76.3%) had a cardiac cause, seven (18.4%) had an extracardiac cause and in two (5.2%) the reason was uncertain.

CONCLUSIONS

Although the leading causes of death in fetuses and children with heterotaxy syndrome are cardiac, a small subset of fetuses have extracardiac anomalies with significant impact on outcome. These anomalies often escape prenatal detection, and therefore neonates at risk should be monitored for bowel obstruction, biliary atresia and immune dysfunction in order to allow timely intervention through a multidisciplinary approach. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.