3D/4D spatiotemporal image correlation (STIC) fetal echocardiography provides incremental benefit over 2D fetal echocardiography in predicting postnatal surgical approach in double-outlet right ventricle.

OBJECTIVE: To analyze the incremental benefit of 3D/4D spatiotemporal image correlation (STIC) fetal echocardiography over 2D fetal echocardiography with respect to the accuracy of identification of anatomic details crucial for surgical decision-making and in predicting surgical approach in fetuses with double-outlet right ventricle (DORV). METHODS: This was a retrospective study of fetuses with DORV which had undergone both 2D echocardiography and 3D/4D STIC echocardiography and which underwent surgery postnatally in a tertiary pediatric cardiac center in Kerala between October 2015 and March 2019. All such cases with normal atrial arrangement, concordant atrioventricular connections and balanced ventricles were included. 2D and 3D/4D STIC fetal echocardiographic data were analyzed by two experienced observers blinded to the other dataset. Anatomic variables crucial for surgical decision-making, i.e. location and routability of the ventricular septal defect, relationship of the great arteries and presence of outflow obstruction, were compared between the two modalities with respect to agreement with postnatal echocardiography. The accuracy of prenatal prediction of the surgical pathway was compared between 2D and 3D/4D modalities with respect to the procedure undertaken. RESULTS: Included in the study were 22 fetuses with DORV which had undergone both 2D and 3D/4D imaging as well as postnatal surgery. Accuracy of prenatal interpretation of all four anatomic variables was significantly higher using 3D/4D STIC than using 2D fetal echocardiography (19/22 (86.4%) vs 8/22 (36.4%), P < 0.001). Surgical procedures included single-stage repair in 14 (63.5%) patients and a multistage approach in eight (36.4%). Prenatal prediction of the surgical pathway was significantly more accurate on 3D/4D STIC than on 2D echocardiography (20/22 (90.9%) vs 12/22 (54.5%), P = 0.021). Prenatal predictive accuracy of single-stage biventricular repair was significantly better for 3D/4D STIC than for 2D echocardiography (14/14 (100%) vs 8/14 (57.1%), P = 0.04). CONCLUSION: Addition of 3D/4D STIC to conventional 2D fetal echocardiography confers incremental benefit on the accuracy of identification of anatomic details crucial for surgical decision-making and the prediction of postnatal surgical approach in fetuses with DORV, thereby potentially aiding prenatal counseling. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Congenital aneurysm of the left atrium associated with double-outlet right ventricle in a trisomy-18 fetus: Case report and literature review.

Congenital aneurysm of the left atrium is a rare cardiac anomaly, most commonly detected between the 2nd and 4th decades of life in a symptomatic patient. We report a congenital aneurysm of the left atrium diagnosed at 24 weeks of gestational age, associated with other congenital heart diseases and 47XY, +18 karyotype. The literature of the left atrial aneurysm diagnosed by fetal echocardiography is also reviewed in this report.

Anatomy of the ventricular septal defect in outflow tract defects: similarities and differences.

OBJECTIVE: The study objective was to analyze the anatomy of the ventricular septal defect found in various phenotypes of outflow tract defects. METHODS: We reviewed 277 heart specimens with isolated outlet ventricular septal defect without subpulmonary stenosis (isolated outlet ventricular septal defect, 19); tetralogy of Fallot (71); tetralogy of Fallot with pulmonary atresia (51); common arterial trunk (54); double outlet right ventricle (65) with subaortic, doubly committed, or subpulmonary ventricular septal defect; and interrupted aortic arch type B (17). Special attention was paid to the rims of the ventricular septal defect viewed from the right ventricular side and the relationships between the tricuspid and aortic valves. RESULTS: The ventricular septal defect was always located in the outlet of the right ventricle, between the 2 limbs of the septal band. There was a fibrous continuity between the tricuspid and aortic valves in 74% of specimens with isolated outlet ventricular septal defect, 66% of specimens with tetralogy of Fallot, 39% of specimens with tetralogy of Fallot with pulmonary atresia, 4.6% of specimens with double outlet right ventricle, 1.8% of specimens with common arterial trunk, and zero of specimens with interrupted aortic arch type B (P < .005). When present, this continuity always involved the anterior tricuspid leaflet. CONCLUSIONS: The ventricular septal defect in outflow tract defects is always an outlet ventricular septal defect, cradled between the 2 limbs of the septal band. However, there are some differences regarding the posteroinferior and superior rims of the ventricular septal defect. These differences suggest an anatomic continuum from the isolated outlet ventricular septal defect to the interrupted aortic arch type B rather than distinct physiologic phenotypes, related to various degrees of abnormal rotation of the outflow tract during heart development: minimal in isolated outlet ventricular septal defect; incomplete in tetralogy of Fallot, tetralogy of Fallot with pulmonary atresia, and double outlet right ventricle; absent in common arterial trunk; and excessive in interrupted aortic arch type B.

Deletion of yes-associated protein (YAP) specifically in cardiac and vascular smooth muscle cells reveals a crucial role for YAP in mouse cardiovascular development.

RATIONALE: Our previous study has shown that yes-associated protein (YAP) plays a crucial role in the phenotypic modulation of vascular smooth muscle cells (SMCs) in response to arterial injury. However, the role of YAP in vascular SMC development is unknown. OBJECTIVE: The goal of this study was to investigate the functional role of YAP in cardiovascular development in mice and determine the mechanisms underlying YAP's actions. METHODS AND RESULTS: YAP was deleted in cardiomyocytes and vascular SMCs by crossing YAP flox mice with SM22α-Cre transgenic mice. Cardiac/SMC-specific deletion of YAP directed by SM22α-Cre resulted in perinatal lethality in mice because of profound cardiac defects including hypoplastic myocardium, membranous ventricular septal defect, and double outlet right ventricle. The cardiac/SMC-specific YAP knockout mice also displayed severe vascular abnormalities including hypoplastic arterial wall, short/absent brachiocephalic artery, and retroesophageal right subclavian artery. Deletion of YAP in mouse vascular SMCs induced expression of a subset of cell cycle arrest genes including G-protein-coupled receptor 132 (Gpr132). Silencing Gpr132 promoted SMC proliferation, whereas overexpression of Gpr132 attenuated SMC growth by arresting cell cycle in G0/G1 phase, suggesting that ablation of YAP-induced impairment of SMC proliferation was mediated, at least in part, by induction of Gpr132 expression. Mechanistically, YAP recruited the epigenetic repressor histone deacetylase-4 to suppress Gpr132 gene expression via a muscle CAT element in the Gpr132 gene. CONCLUSIONS: YAP plays a critical role in cardiac/SMC proliferation during cardiovascular development by epigenetically regulating expression of a set of cell cycle suppressors.

Three-dimensional fetal echocardiography for prediction of postnatal surgical approach in double outlet right ventricle: a pilot study.

OBJECTIVES: To examine the feasibility of reconstructing three-dimensional (3D) echocardiographic views in fetuses with double outlet right ventricle, which might enhance prognostication with respect to the postnatal surgical approach. METHODS: This was a retrospective blinded observational study. Our database was reviewed from January 2007 to June 2011 to identify fetuses with usual atrial arrangement, concordant atrioventricular connections, double outlet right ventricle and relatively balanced left and right ventricular size. Six fetuses, in which there was an intention to treat, were included. RESULTS: In all six cases, we identified important features, including location of the ventricular septal defect and its relation to the atrioventricular valves and great arteries. The postnatal surgical approach was predicted accurately in each case. CONCLUSION: In this group of fetuses with double outlet right ventricle, detailed evaluation by 3D fetal echocardiography enhanced visualization of the anatomy, leading to accurate prediction of the type of surgical repair. Prospective validation in a large cohort of fetuses is warranted.

Double outlet right ventricle versus aortic dextroposition: morphologically distinct defects.

This study concerns the morphological differentiation between double outlet right ventricle (DORV) and aortic dextroposition (AD) defects, namely tetralogy of Fallot and Eisenmenger anomaly. Indeed, despite the similar condition in terms of sequential ventriculo-arterial connections, DORV and AD are two distinct morphological entities. It is proposed that the borderline between these two groups of malformations is represented by the specific insertion of the infundibular septum into the left anterior cranial division of the septomarginal trabeculation (or septal band) occurring in ADs and lacking in DORV. Furthermore, the spiraliform versus straight parallel arrangement of the great arteries in the two groups of anomalies is emphasized as an additional and distinctive morphological feature. Emphasis is also given to the association of straight parallel great arteries conotruncal malformations, DORV and transposition of the great arteries, with the asplenia type of heterotaxy laterality defects. Within this context, the absence of subaortic ventricular septal defect and concomitantly of spiraliform great arteries in the asplenia group of heterotaxy anomalies, as detected by this study, further substantiates our belief of not mixing collectively the ADs with the DORV in clinico-pathological diagnosis.

Doble salida de ventrículo derecho: Enfoque embriológico / Double outlet right ventricle: Embryological approach

Objetivo: Se presenta una explicación patogenética sobre la morfogénesis de la doble salida de ventrículo derecho que explica su origen. Método: Se describieron 35 corazones con doble salida de ventrículo derecho, 15 con grandes arterias ligeramente cruzadas, 10 con arterias lado a lado y 10 con aorta anterior y pulmonar posterior. Se comparó el plano de separación de las vías de salida y de las grandes arterias en los 3 tipos de esta cardiopatía, con el plano de la tabicación troncoconal normal del corazón embrionario. Se determinó el plano cefálico del tabique troncoconal y se comparó con la posición de su borde inferior, con lo cual se calculó el grado de torsión troncoconal en cada grupo de esta cardiopatía; esto permitió inferir el tipo de giro de ese tabique en las 3 formas anatómicas mencionadas. Resultados: En las grandes arterias ligeramente cruzadas el giro troncoconal fue de 135°,en las arterias lado a lado fue de 90°, en la aorta anterior derecha fue de 0° y en la aorta anterior izquierda fue de -90°. Conclusión: Embriológicamente esta cardiopatía se origina por persistencia de la continuidad entre el ventrículo derecho y el troncocono, que origina las vías de salida y las grandes arterias. Sus variantes anatómicas se originan por una detorsión progresiva del tabique troncoconal continuada con una torsión de -90°.

Objective: It is proposed a pathogenetic explanation that explains the morphogenesis of the anatomic variants of double outlet right ventricle. Method: An anatomic embryological correlation was made in which the plane separating the outlets and great arteries in the types of this cardiopathy was compared with the normal truncoconal septum in the embryonic heart. Thirty five hearts with double outlet right ventricle were described, fifteen with great arteries slightly crossed, ten with side by side great arteries and ten with anterior aorta and posterior pulmonary artery. The cephalic border of the truncoconal septum was compared with its inferior border in each group. With this procedure we calculated the type of torsion of the truncoconal septum. Results: In the slightly crossed great arteries the truncoconal twist was of 135° in side by side great arteries the twist was of 90° and in anterior right aorta the truncoconal septum was straight with 0° of rotation, and with left anterior aorta the rotation was of -90°. Conclusion: Embryologically double outlet right ventricle is originated by the persisting continuity between the right ventricle with the truncus and conus which form the great arteries and their outlets. The anatomic variations are the consequence of progressive detortion of the truncoconal septum followed by a torsion of -90°.

[Double outlet right ventricle. Embryological approach]. / Doble salida de ventrículo derecho. Enfoque embriológico.

OBJECTIVE: It is proposed a pathogenetic explanation that explains the morphogenesis of the anatomic variants of double outlet right ventricle. METHOD: An anatomic embryological correlation was made in which the plane separating the outlets and great arteries in the types of this cardiopathy was compared with the normal truncoconal septum in the embryonic heart. Thirty five hearts with double outlet right ventricle were described, fifteen with great arteries slightly crossed, ten with side by side great arteries and ten with anterior aorta and posterior pulmonary artery. The cephalic border of the truncoconal septum was compared with its inferior border in each group. With this procedure we calculated the type of torsion of the truncoconal septum. RESULTS: In the slightly crossed great arteries the truncoconal twist was of 135° in side by side great arteries the twist was of 90° and in anterior right aorta the truncoconal septum was straight with 0° of rotation, and with left anterior aorta the rotation was of -90°. CONCLUSION: Embryologically double outlet right ventricle is originated by the persisting continuity between the right ventricle with the truncus and conus which form the great arteries and their outlets. The anatomic variations are the consequence of progressive detortion of the truncoconal septum followed by a torsion of -90°.

Histone deacetylase 3 regulates smooth muscle differentiation in neural crest cells and development of the cardiac outflow tract.

RATIONALE: The development of the cardiac outflow tract (OFT) and great vessels is a complex process that involves coordinated regulation of multiple progenitor cell populations. Among these populations, neural crest cells make important contributions to OFT formation and aortic arch remodeling. Although numerous signaling pathways, including Notch, have been implicated in this process, the role of epigenetics in OFT development remains largely unexplored. OBJECTIVE: Because histone deacetylases (Hdacs) play important roles in the epigenetic regulation of mammalian development, we have investigated the function of Hdac3, a class I Hdac, during cardiac neural crest development in mouse. METHODS AND RESULTS: Using 2 neural crest drivers, Wnt1-Cre and Pax3(Cre), we show that loss of Hdac3 in neural crest results in perinatal lethality and cardiovascular abnormalities, including interrupted aortic arch type B, aortic arch hypoplasia, double-outlet right ventricle, and ventricular septal defect. Affected embryos are deficient in aortic arch artery smooth muscle during midgestation, despite intact neural crest cell migration and preserved development of other cardiac and truncal neural crest derivatives. The Hdac3-dependent block in smooth muscle differentiation is cell autonomous and is associated with downregulation of the Notch ligand Jagged1, a key driver of smooth muscle differentiation in the aortic arch arteries. CONCLUSIONS: These results indicate that Hdac3 plays a critical and specific regulatory role in the neural crest-derived smooth muscle lineage and in formation of the OFT.

Double outlet right ventricle: aetiologies and associations.

BACKGROUND: Double outlet right ventricle (DORV), a clinically significant congenital heart defect, occurs in 1-3% of individuals with congenital heart defects. In contrast to other major congenital heart defects, there are no systematic or comprehensive data regarding associations, aetiologies, and pathogenesis of DORV. We analysed reported cases in the medical literature to address these issues. METHODS: We queried the PubMed database using key words "double outlet right ventricle" and "DORV" for case reports, epidemiologic analyses and animal studies with this cardiac anomaly. The anatomic subtype of DORV was classified according to criteria of Van Praagh. RESULTS: Chromosomal abnormalities were present in 61 of the 149 cases of DORV. Trisomies 13 and 18, and del 22q11 were the most commonly associated cytogenetic lesions; different anatomic subtypes of DORV were noted in trisomies 13 and 18 versus del 22q11. DORV was reported in many uncommon or rare non-chromosomal syndromes. Mutations and non-synonymous sequence variants in the CFC1 and CSX genes were the most commonly reported monogenic loci associated with DORV in humans; numerous genes are reported in murine models of DORV. Animal studies implicate maternal diabetes and prenatal exposure to ethanol, retinoids, theophylline, and valproate in DORV teratogenesis. CONCLUSIONS: The large number of genes associated with DORV in both humans and animal models and the different anatomic subtypes seen in specific aetiologies indicate the likelihood of several distinct pathogenetic mechanisms for DORV, including impairment of neural crest derivative migration and impairment of normal cardiac situs and looping.

Transforming growth factor beta-SMAD2 signaling regulates aortic arch innervation and development.

Aortic arch interruptions in humans and animal models are mainly caused by aberrant development of the fourth pharyngeal arch artery. Little is known about the maturation of this vessel during normal and abnormal development, which is the subject of this study. Tgfbeta2 knockout mice that present with fourth artery defects have been associated with defective neural crest cell migration. In this study, we concentrated on pharyngeal arch artery development during developmental days 12.5 to 18.5, focusing on neural crest cell migration using a Wnt1-Cre by R26R neural crest cell reporter mouse. Fourth arch artery maturation was studied with antibodies directed against smooth muscle alpha-actin and neural NCAM-1 and RMO-270. For diminished transforming growth factor beta (TGF-beta) signaling, SMAD2 and fibronectin have been analyzed. Neural crest migration and differentiation into smooth muscle cells is unaltered in mutants, regardless of the cardiovascular defect found; however, innervation of the fourth arch artery is affected. Absent staining for nuclear SMAD2, NCAM-1, and RMO-270 in the fourth artery in mutant coincides with severe defects of this segment. Likewise, fibronectin expression is diminished in these cases. From these data we conclude the following: (1) neural crest cell migration is not a common denominator in cardiovascular defects of Tgfbeta2-/- mice; (2) fourth arch artery maturation is a complex process involving innervation; and (3) TGF-beta2 depletion diminishes SMAD2-signaling in the fourth arch artery and coincides with reduced vascular NCAM-1 expression and neural innervation of this artery. We hypothesize that disturbed maturation of the fourth pharyngeal arch artery, and especially abrogated vascular innervation, will result in fourth arch interruptions.

Cardiovascular defects associated with abnormalities in midline development in the Loop-tail mouse mutant.

Loop-tail (Lp) is a naturally occurring mouse mutant that develops severe neural tube defects. In this study, we describe complex cardiovascular defects in Lp homozygotes, which include double-outlet right ventricle, with obligatory perimembranous ventricular septal defects, and double-sided aortic arch, with associated abnormalities in the aortic arch arteries. Outflow tract and aortic arch defects are often related to abnormalities in the cardiac neural crest, but using molecular and anatomic markers, we show that neural crest migration is normal in Lp/Lp embryos. On the other hand, the heart fails to loop normally in Lp/Lp embryos, in association with incomplete axial rotation and reduced cervical flexion. As a consequence, the ventricular loop is shifted posteromedially relative to its position in wild-type embryos. This suggests that the observed cardiac alignment defects in the Lp mutant may be secondary to failure of neural tube closure and incomplete axial rotation. Double-sided aortic arch is a rare finding among mouse models. In humans, it is usually an isolated malformation, only rarely occurring in combination with other cardiac defects. We suggest that the double-sided arch arises as a primary defect in the Lp mutant, unrelated to the alignment defects, perhaps reflecting a role for the (as-yet-unknown) Lp gene in maintenance/regression of the aortic arch system.

Embryological observations on the morphogenesis of double-outlet right ventricle with subaortic ventricular septal defect and normal arrangement of the great arteries.

Double-outlet ventricle (DORV) is generally regarded as a congenital heart defect resulting from impaired morphogenesis of either the outflow portion (conotruncus) or the conoventricular flange (crista prima) of the embryonic heart. However, we demonstrate in this study chicken fetal hearts with DORV in which the conotruncal derivatives (great arteries and subpulmonary part of the ventricular septum = conus septum) and the region of the crista prima are normally developed. The anomalies leading to DORV under these conditions are found at the atrioventricular region. The posterior-anterior axis of the tricuspid orifice is not directed to the right anterior but to the left anterior side of the heart. Thereby the posterior connection line between the muscular ventricular septum and conus septum, which usually follows the left margin of the tricuspid orifice, is not connected to the right portion of the conus septum but instead is directed towards the left portion of the conus septum. In consequence of the abnormal connection between the muscular ventricular septum and the conus septum, the interventricular foramen is formed at the left side of the subaortic flow path. The subaortic flow path arises from the right ventricle. These findings show that DORV can result not only from impaired development of the conotruncus or conoventricular flange, but also from abnormal development of the atrioventricular region. We suggest distinguishing between conotruncal, conoventricular (crista prima), and atrioventricular types of DORV.

Pathogenesis of various forms of double outlet right ventricle in mouse fetal trisomy 13.

The pathogenesis of double outlet right ventricle with or without pulmonary infundibular atresia in mouse fetal trisomy 13 was studied at the organ level using microdissection and scanning electron microscopy. Altogether, 394 karyotyped trisomic embryos were collected between 11 days and 16 hours of gestation (presence of a vaginal plug = day 1) and 15 days of gestation at intervals of 8 hours, and at 16 days of gestation. The hearts were perfusion-fixed, microdissected, and prepared to be observed in scanning electron microscope in the following standardized orientations: frontal, right or left profile, septal and parietal halves of the right ventricle and outflow tract (conotruncus). Comparison of 276 trisomic hearts with their normal counterparts described previously has shown that: the first pathognomonic feature is the abnormal anterior position of the proximal part of the parietal outflow tract ridge or of both ridges (at 12 days and 16 hours of gestation); the abnormal anterior fusion of these ridges ("coalescence") results in a mesenchymal mass behind which is deviated the pulmonary part of the outflow tract lumen; from 14 days and 16 hours of gestation on, this lumen is either obstructed, resulting in a supravalvar stenosis of the pulmonary trunk and subsequently evolving into double outlet right ventricle with pulmonary infundibular atresia; or, in a minority of cases, this lumen is not obstructed and the heart develops into double outlet right ventricle without pulmonary infundibular atresia. The pathogenesis of these malformations differs from most of the known hypotheses based on deductions from human malformed hearts, as well as from observations of the pathogenesis of similar outflow tract malformations, such as those found in the Keeshond dog or rats treated with trimethadione.