Extracardiac anomalies in prenatally diagnosed heterotaxy syndrome

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.

Difficulty in the Diagnosis of Biliary Atresia Splenic Malformation Syndrome In Utero

The fetus of a 30-year-old pregnant Japanese woman was diagnosed with absence of inferior vena cava (IVC) and azygos continuation of interrupted IVC without cardiac anomalies at 34 weeks of gestation, and a healthy male neonate weighing 2,910 g was delivered at 37 weeks of gestation. On day 42 after birth, direct bilirubin predominant hyperbilirubinemia and high serum gamma-GTP levels were detected. Computed tomography revealed the presence of a lobulated and accessory spleen, and laparotomy demonstrated type III biliary atresia (BA), confirming the final diagnosis of BA splenic malformation (BASM) syndrome. In retrospect, non-visualization of the gallbladder was missed in utero. The combination of the absence of IVC and BA without cardiac anomalies is far less likely to occur in left isomerism. Although BA remains difficult to detect in utero, special attention should be paid to cases of BA associated with findings of left isomerism, including the absence of IVC, to enable early diagnosis and treatment of BASM.

Dysmorphic Gallbladder Found on Prenatal Ultrasound as a Hint for Biliary Atresia

Biliary atresia (BA) is a rare but devastating cholangiopathy. We report a case series of dysmorphic gallbladders detected during prenatal ultrasound, which were confirmed as BA after birth. We present the prenatal ultrasound findings as well as integral follow-up, with an aim to raise awareness regarding the association between BA and dysmorphic gallbladder. Although this dysmorphic gallbladder is a strong hint for BA, it is also important to search for other related sonographic features, such as the presence of microcysts at the hepatic hilum, dilated right hepatic artery, and seroperitoneum, which may provide more evidence for the diagnosis of BA.

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.

Clinical implications of airway anomalies and stenosis in patients with heterotaxy syndrome

In heterotaxy syndrome, bronchopulmonary situs usually reflects atrial situs, resulting in either right (RAI) or left atrial isomerism (LAI). This study determines airway anomalies and its implications in patients with heterotaxy. This retrospective study included 223 patients with heterotaxy syndrome who received an integrated cardiac computed tomography evaluation. Patient database from 1995 to 2020 was reviewed. The patients were examined by a congenital heart disease team comprising pediatric cardiologists, radiologists, pulmonologists, and cardiovascular surgeons. Among the 223 patients, 189 (84.8%, M/F  =  1.66) had RAI and 29 had LAI (13.0%, M/F  =  0.71). Five patients had indeterminate isomerism (2.2%, M/F  = 1.5). Discordant bronchopulmonary and atrial situs occurred in 4% patients, while discordant bronchopulmonary, atrial, and splenic situs occurred in 23.2% patients. Lower airway stenosis was observed in 61 patients (27.4%), including 27.5%, 20.7%, and 60% RAI, LAI, and indeterminate isomerism patients, respectively (p = 0.189). One patient had an intrinsic long segment lower tracheal stenosis and received slide tracheoplasty. Initial cardiac operation was performed in 213 patients. Higher surgical mortality occurred in patients with RAI (19.5% vs. none for LAI and indeterminate isomerism, p = 0.038). In patients with RAI, lower airway anomaly/stenosis increased the duration of ventilator usage (p = 0.030) but did not affect surgical mortality. Total anomalous pulmonary venous return to systemic veins and pulmonary venous stenosis were major surgical risk factors. Bronchopulmonary isomerism shares a similar isomeric pattern to cardiac atrial appendage. Lower airway anomalies/stenosis was common in patients with heterotaxy, resulting in prolonged ventilator therapy in patients with RAI.

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.

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.

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.

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.

Fetal Ultrasonic Evaluation of Bronchial Morphology in Fetuses with Isomerism

OBJECTIVE

The aim of the study was to evaluate whether fetal ultrasound could determine bronchial isomerism and distinguish left isomerism from right isomerism.

METHODS

We identified 110 healthy fetuses and 28 fetuses with isomerism. The outer angle between the tracheal midline and the inner margin of the bronchus is measured. The bronchial angles and the ratio of left/right bronchial angle were used to differentiate bronchial morphology and confirm the presence of bronchial isomerism in pathological cases.

RESULTS

The normal angles of the left and right bronchi were 146.98° (95% CI, 145.15-147.81°) and 167.37° (95% CI, 166.30-168.44°), separately. The cutoff bronchial angle of 156.5° was used to distinguish left bronchus from right bronchus. The bronchial isomerism could be identified in all pathological cases by autopsy and bronchial-atrial concordance occurred in 27 pathological cases (96.4%). In 21 pathological cases, the bilateral bronchial angle was <156.5 versus >156.5 differentiated left from right isomerism, respectively. The ratio of the left/right bronchial angle of >0.935 identified 92.9% (26/28) of all pathological cases, with a sensitivity of 89.7%.

CONCLUSIONS

Fetal ultrasound can detect the bronchial morphology and the presence of bronchial isomerism in fetuses with isomerism according to bronchial angles and the ratio of left/right bronchial angle.

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..

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.

A novel DNAH11 variant segregating in a sibship with heterotaxy and implications for genetic counseling

Background

Isomerism or heterotaxy syndrome is the loss of normal asymmetry of the internal thoraco‐abdominal organs in the left‐right axis and is associated with cardiovascular malformations. Mutations within DNAH11 can be associated with primary ciliary dyskinesia and heterotaxy syndromes.

Methods

We report a family of healthy, nonconsanguinous parents with subsequent pregnancies demonstrating a novel likely pathogenic variant in DNAH11 segregating in a sibship with varied presentations.

Result

The first affected pregnancy presented with right atrial isomerism. Further DNA testing identified three variants in DNAH11 related to primary ciliary dyskinesia: a maternally inherited heterozygous variant of unknown significance (VUS) c.2772G>A (p.Met924Ile), a maternally inherited novel likely pathogenic variant c.11662C>T (p.Arg3888Cys) as well as a paternally inherited pathogenic c.1648delA variant (p.Arg550GlyfsX16). The second pregnancy inherited the same variants including the pathogenic and likely pathogenic DNAH11 variants and presented with left isomerism and extracardiac abnormalities.

Conclusion

We present a novel likely pathogenic variant (c.11662C>T) in DNAH11 that has manifested in heterotaxy with variability in phenotypes for subsequent pregnancies of common parents. This report demonstrates that sibship illustrates potential variability in phenotypes associated with the same pathogenic variants within a family and highlights the difficulty in genetic counseling due to the variation in clinical presentation.

Large intestine embryogenesis: Molecular pathways and related disorders (Review)

The large intestine, part of the gastrointestinal tract (GI), is composed of all three germ layers, namely the endoderm, the mesoderm and the ectoderm, forming the epithelium, the smooth muscle layers and the enteric nervous system, respectively. Since gastrulation, these layers develop simultaneously during embryogenesis, signaling to each other continuously until adult age. Two invaginations, the anterior intestinal portal (AIP) and the caudal/posterior intestinal portal (CIP), elongate and fuse, creating the primitive gut tube, which is then patterned along the antero‑posterior (AP) axis and the radial (RAD) axis in the context of left‑right (LR) asymmetry. These events lead to the formation of three distinct regions, the foregut, midgut and hindgut. All the above‑mentioned phenomena are under strict control from various molecular pathways, which are critical for the normal intestinal development and function. Specifically, the intestinal epithelium constitutes a constantly developing tissue, deriving from the progenitor stem cells at the bottom of the intestinal crypt. Epithelial differentiation strongly depends on the crosstalk with the adjacent mesoderm. Major molecular pathways that are implicated in the embryogenesis of the large intestine include the canonical and non‑canonical wingless‑related integration site (Wnt), bone morphogenetic protein (BMP), Notch and hedgehog systems. The aberrant regulation of these pathways inevitably leads to several intestinal malformation syndromes, such as atresia, stenosis, or agangliosis. Novel theories, involving the regulation and homeostasis of intestinal stem cells, suggest an embryological basis for the pathogenesis of colorectal cancer (CRC). Thus, the present review article summarizes the diverse roles of these molecular factors in intestinal embryogenesis and related disorders.

Prenatal diagnosis of asplenia syndrome with sliding hiatus hernia in a fetus

We report a case of right isomerism with a complex congenital heart disease associated with hiatus hernia in a 19-week-old fetus with relevant review of literature. This report highlights the importance of having a proper checklist for prenatal identification of extracardiac manifestations of isomerism syndromes. This will enable us to provide an effective family-centered counseling for perinatal management of these complex lesions. To our knowledge, prenatal sonographic detection of a sliding hiatal hernia in a fetus with right isomerism has not been reported previously.

Comorbidities in situs inversus totalis: A hospital-based study

BACKGROUND AND OBJECTIVE

Few studies have assessed the comorbid diseases in situs inversus totalis (SIT) comprehensively. The aim of this study was to provide insight into the spectrum and prevalence of comorbidities in SIT.

METHODS

Children ≤18 years of age with SIT were enrolled in this retrospective observational study. Situs status and comorbidities were independently confirmed by two physicians, based on review of radiologic, ultrasonic examination, operative records, and case notes.

RESULTS

A total of 155 children (median age: 1.24 years; range: 1 day-17.8 years) confirmed to have SIT were recruited between January 2008 and December 2018. Associated conditions were diagnosed in 114 children (73.5%). Among them, 25 children (16.1%) had multiple anomalies affecting two or more organ systems. The most commonly associated conditions were congenital heart defects (n = 72, 46.5%) followed by primary ciliary dyskinesia (n = 19, 12.3%), renal disorders (n = 12, 7.7%), biliary atresia (n = 7, 4.5%), skeletal dysplasia (n = 8, 5.2%), and mental retardation (n = 4, 2.6%).

CONCLUSION

A substantial proportion of children with SIT have comorbidities affecting multiple systems, especially cardiovascular and respiratory abnormalities. Children with SIT warrant careful examination for the presence of congenital and acquired abnormalities.

Left atrial isomerism associated with aneurysmal enlargement of right atrial appendage: A case report with literature review

We present a prenatally diagnosed case of heterotaxy syndrome (HS) in which left atrial isomerism (LAI) was associated with an aneurysmal enlargement of the right atrial appendage (RAA). Although LAI is usually associated with complex cardiac and extracardiac anomalies, the association of LAI and right atrial appendage aneurysm (RAAA) is exceptional. Congenital RAAA itself is an idiopathic, very rare cardiac anomaly characterized by the enlargement of the appendage in the absence of any other cardiac or extra-cardiac defect. The prognosis of the heterotaxy is poor with associated major cardiac malformations and even cases with minor cardiac anomalies are at risk postnatally for complications like biliary atresia, intestinal rotational abnormalities, and immune disorders. In this case, the prenatal diagnosis of the isomerism was mainly based on the abnormalities of caval veins. Although no typical complex cardiac anomaly was present, the HS was associated with biliary atresia, polysplenia, and malrotation of the gut. Associated RAAA further imposed an additional risk of complications such as tachyarrhythmias, thromboembolic events, and aneurysmal rupture.

Increased mortality, morbidities, and costs after heart transplantation in heterotaxy syndrome and other complex situs arrangements

OBJECTIVES

Identify pediatric heart transplant (HT) recipients with heterotaxy and other complex arrangements of cardiac situs (heterotaxy/situs anomaly) and compare mortality, morbidities, length of stay (LOS), and costs to recipients with congenital heart disease without heterotaxy/situs anomaly.

METHODS

Using linked registry data (2001-2016), we identified 186 HT recipients with heterotaxy/situs anomaly and 1254 with congenital heart disease without heterotaxy/situs anomaly. We compared post-HT outcomes in univariable and multivariable time-to-event analyses. LOS and cost from HT to discharge were compared using Wilcoxon rank-sum tests. Sensitivity analyses were performed using stricter heterotaxy/situs anomaly group inclusion criteria and through propensity matching.

RESULTS

HT recipients with heterotaxy/situs anomaly were older (median age, 5.1 vs 1.6 years; P < .001) and more often black, Asian, Hispanic, or "other" nonwhite (54% vs 32%; P < .001). Heterotaxy/situs anomaly was independently associated with increased mortality (hazard ratio, 1.58; 95% confidence interval, 1.19-2.09; P = .002), even among 6-month survivors (hazard ratio, 1.86; 95% confidence interval, 1.09-3.16; P = .021). Heterotaxy/situs anomaly recipients more commonly required dialysis (odds ratio, 2.58; 95% confidence interval, 1.51-4.42; P = .001) and cardiac reoperation (odds ratio, 1.91; 95% confidence interval, 1.17-3.11; P = .010) before discharge. They had longer ischemic times (19.2 additional minutes [range, 10.9-27.5 minutes]; P < .001), post-HT intensive care unit LOS (16 vs 13 days; P = .012), and hospital LOS (26 vs 23 days; P = .005). Post-HT hospitalization costs were also greater ($447,604 vs $379,357; P = .001).

CONCLUSIONS

Heterotaxy and other complex arrangements of cardiac situs are associated with increased mortality, postoperative complications, LOS, and costs after HT. Although increased surgical complexity can account for many of these differences, inferior late survival is not well explained and deserves further study.

The left-right asymmetry of liver lobation is generated by Pitx2c-mediated asymmetries in the hepatic diverticulum

Internal organs exhibit left-right asymmetric sizes, shapes and anatomical positions, but how these different lateralities develop is poorly understood. Here we use the experimentally tractable Xenopus model to uncover the morphogenetic events that drive the left-right asymmetrical lobation of the liver. On the right side of the early hepatic diverticulum, endoderm cells become columnar and apically constricted, forming an expanded epithelial surface and, ultimately, an enlarged right liver lobe. In contrast, the cells on the left side become rounder, and rearrange into a compact, stratified architecture that produces a smaller left lobe. Side-specific gain- and loss-of-function studies reveal that asymmetric expression of the left-right determinant Pitx2c elicits distinct epithelial morphogenesis events in the left side of the diverticulum. Surprisingly, the cellular events induced by Pitx2c during liver development are opposite those induced in other digestive organs, suggesting divergent cellular mechanisms underlie the formation of different lateralities.

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.

Comparing levocardia and dextrocardia in fetuses with heterotaxy syndrome: prenatal features, clinical significance and outcomes

Background

To investigate the differences in cardiovascular disease, extracardiac anomalies and outcomes between fetuses with levocardia and dextrocardia.

Methods

Clinical demographics, prenatal features, postnatal characteristics and the outcomes of fetuses with levocardia or dextrocardia were recorded and analyzed.

Results

Sixty-five fetuses with dextrocardia and thirty-eight fetuses with levocardia were enrolled. Right ventricle outlet obstruction, atrioventricular septal defect and intestinal malrotation were common in both groups. Univentricular physiology, transposition of the great arteries and esophageal atresia were more frequent in fetuses with levocardia, whereas abnormal pulmonary venous connection, double outlet of right ventricle, left ventricle outlet obstruction and brain abnormalities were more frequent in the dextrocardia group. The accuracy of evaluating cardiac malformations was high, but the sensitivity in assessing extracardiac abnormalities was low.

Conclusions

Although the disorders have certain overlapping features, there are several differences between fetuses with levocardia and dextrocardia. These findings might improve patient counseling and perinatal management.

A case of prenatally detected left isomerism and hemiazygos continuation of inferior vena cava

Heterotaxy syndromes are defined as the disorders that involve abnormal arrangement of viscera. We present a case of prenatally diagnosed left isomerism in a 30-year-old primigravida woman referred to our hospital for complex cardiac abnormality. Sonographic findings included heart block, unbalanced atrioventricular septal defect, interruption of the inferior vena cava with hemiazygos continuation, double superior vena cava, a right-sided stomach, and biliary atresia. The hemiazygos vein drained into the right atrium by the persistent left superior vena cava. This type of inferior vena cava interruption and continuation is rarely reported in prenatally detected cases of left isomerism. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:430-433, 2017.

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.