Molecular Pathways and Animal Models of Truncus Arteriosus.

In normal cardiovascular development in birds and mammals, the outflow tract of the heart is divided into two distinct channels to separate the oxygenated systemic blood flow from the deoxygenated pulmonary circulation. When the process of outflow tract septation fails, a single common outflow vessel persists resulting in a serious clinical condition known as persistent truncus arteriosus or common arterial trunk. In this chapter, we will review molecular pathways and the cells that are known to play a role in the formation and development of the outflow tract and how genetic manipulation of these pathways in animal models can result in common arterial trunk.

Right Ventricular Outflow Tract Reconstruction in Truncus Arteriosus: A 30-Year Two-Center Comparison between Homografts and Bovine Jugular Vein.

INTRODUCTION: Homografts and bovine jugular vein are the most commonly used conduits for right ventricular outflow tract reconstruction at the time of primary repair of truncus arteriosus. METHODS: We reviewed all truncus patients from 1990 to 2020 in two mid-volume centers. Inclusion criteria were primary repair, age under one year, and implantation of either homograft or bovine jugular vein. Kaplan-Meier analysis was used to estimate survival, freedom from reoperation on right ventricular outflow tract, and freedom from right ventricular outflow tract reoperation or catheter intervention. RESULTS: Seventy-three patients met the inclusion criteria, homografts were implanted in 31, and bovine jugular vein in 42. There was no difference in preoperative characteristics between the two groups. There were 25/73 (34%) early postoperative deaths and no late deaths. Follow-up for survivals was 17.5 (interquartile range 13.5) years for homograft group, and 11.5 (interquartile range 8.5) years for bovine jugular vein group (P=0.002). Freedom from reoperation on right ventricular outflow tract at one, five, and 10 years in the homograft group were 100%, 83%, and 53%; and in bovine jugular vein group, it was 100%, 85%, and 50% (P=0.79). There was no difference in freedom from reoperation or catheter intervention (P=0.32). CONCLUSION: Bovine jugular vein was equivalent to homografts up to 10 years in terms of survival and freedom from right ventricular outflow tract reoperation or catheter intervention. The choice of either valved conduit did not influence the durability of the right ventricle-pulmonary artery conduit in truncus arteriosus.

Truncus Arteriosus and Absent Ascending Aorta With Unusual Head and Neck Vessel Origins.

We describe a neonate with a unique variant of truncus arteriosus with interrupted aortic arch, an absent ascending aorta, persistent right dorsal aorta, and an unusual brachiocephalic artery pattern in which all head and neck vessels were supplied from the ductal arch-descending aorta continuum. (Level of Difficulty: Beginner.).

Laparoscopic radical resection for rectal cancer in a patient with uncorrected truncus arteriosus type IV: A case report.

Persistent truncus arteriosus is a rare congenital heart malformation which if not corrected, results in the death of about 50% of the patients, while fewer than 20% of the patients survive the first year of life. Here, we report the successful anesthetic management of an adult patient with uncorrected truncus arteriosus who presented for the laparoscopic radical resection of rectal cancer.

Resección radical laparoscópica para el cáncer de recto en un paciente con tronco arterioso no corregido tipoIV: informe de un caso / Laparoscopic radical resection for rectal cancer in a patient with uncorrected truncus arteriosus typeIV: A case report

El tronco arterioso persistente es una malformación cardíaca congénita poco frecuente. Si no se corrige, aproximadamente el 50% de los que lo padecen mueren; menos del 20% de estos pacientes sobreviven al primer año de vida. Presentamos el manejo anestésico exitoso de un paciente adulto con tronco arterioso no corregido que se sometió a resección radical laparoscópica de cáncer de recto.(AU)

Persistent truncus arteriosus is a rare congenital heart malformation which if not corrected, results in the death of about 50% of the patients, while fewer than 20% of the patients survive the first year of life. Here, we report the successful anesthetic management of an adult patient with uncorrected truncus arteriosus who presented for the laparoscopic radical resection of rectal cancer.(AU)

Right Ventricular Outflow Tract Reconstruction in Truncus Arteriosus: A 30-Year Two-Center Comparison between Homografts and Bovine Jugular Vein

ABSTRACT Introduction: Homografts and bovine jugular vein are the most commonly used conduits for right ventricular outflow tract reconstruction at the time of primary repair of truncus arteriosus. Methods: We reviewed all truncus patients from 1990 to 2020 in two mid-volume centers. Inclusion criteria were primary repair, age under one year, and implantation of either homograft or bovine jugular vein. Kaplan-Meier analysis was used to estimate survival, freedom from reoperation on right ventricular outflow tract, and freedom from right ventricular outflow tract reoperation or catheter intervention. Results: Seventy-three patients met the inclusion criteria, homografts were implanted in 31, and bovine jugular vein in 42. There was no difference in preoperative characteristics between the two groups. There were 25/73 (34%) early postoperative deaths and no late deaths. Follow-up for survivals was 17.5 (interquartile range 13.5) years for homograft group, and 11.5 (interquartile range 8.5) years for bovine jugular vein group (P=0.002). Freedom from reoperation on right ventricular outflow tract at one, five, and 10 years in the homograft group were 100%, 83%, and 53%; and in bovine jugular vein group, it was 100%, 85%, and 50% (P=0.79). There was no difference in freedom from reoperation or catheter intervention (P=0.32). Conclusion: Bovine jugular vein was equivalent to homografts up to 10 years in terms of survival and freedom from right ventricular outflow tract reoperation or catheter intervention. The choice of either valved conduit did not influence the durability of the right ventricle-pulmonary artery conduit in truncus arteriosus.

Single Cell Sequencing Reveals Mechanisms of Persistent Truncus Arteriosus Formation after PDGFRα and PDGFRß Double Knockout in Cardiac Neural Crest Cells.

Persistent truncus arteriosus (PTA) is an uncommon and complex congenital cardiac malformation accounting for about 1.2% of all congenital heart diseases (CHDs), which is caused by a deficiency in the embryonic heart outflow tract's (OFT) septation and remodeling. PDGFRα and PDGFRß double knockout (DKO) in cardiac neural crest cells (CNCCs) has been reported to cause PTA, but the underlying mechanisms remain unclear. Here, we constructed a PTA mouse model with PDGFRα and PDGFRß double knockout in Pax3+ CNCCs and described the condensation failure into OFT septum of CNCC-derived cells due to disturbance of cell polarity in the DKO group. In addition, we further explored the mechanism with single-cell RNA sequencing. We found that two main cell differentiation trajectories into vascular smooth muscle cells (VSMCs) from cardiomyocytes (CMs) and mesenchymal cells (MSs), respectively, were interrupted in the DKO group. The process of CM differentiation into VSMC stagnated in a transitional CM I-like state, which contributed to the failure of OFT remodeling and muscular septum formation. On the other hand, a Penk+ transitional MS II cluster closely related to cell condensation into the OFT septum disappeared, which led to the OFT's septation absence directly. In conclusion, the disturbance of CNCC-derived cells caused by PDGFRα and PDGFRß knockout can lead to the OFT septation disorder and the occurrence of PTA.

Over-expression of Fgf8 in cardiac neural crest cells leads to persistent truncus arteriosus.

During cardiogenesis, the outflow tract undergoes a complicated morphogenesis, including the re-alignment of the great blood vessels, and the separation of aorta and pulmonary trunk. The deficiency of FGF8 in the morphogenesis of outflow tract has been well studied, however, the effect of over-dosed FGF8 on the development of outflow tract remains unknown. In this study, Rosa26R-Fgf8 knock-in allele was constitutively activated by Wnt1-cre transgene in the mouse neural crest cells presumptive for the endocardial cushion of outflow tract. Surprisingly, Wnt1-cre; Rosa26R-Fgf8 mouse embryos exhibited persistent truncus arteriosus and died prior to E15.5. The cardiac neural crest cells in Wnt1-cre; Rosa26R-Fgf8 truncus arteriosus did not degenerate as in WT controls, but proliferated into a thickened endocardial cushion and then, blocked the blood outflow from cardiac chambers into the lungs, which resulted in the embryonic lethality. Although the spiral aorticopulmonary septum failed to form, the differentiaion of the endothelium and smooth muscle in the Wnt1-cre; Rosa26R-Fgf8 truncus arteriosus were impacted little. However, lineage tracing assay showed that the neural crest derived cells aggregated in the cushion layer, but failed to differentiate into the endothelium of Wnt1-cre; Rosa26R-Fgf8 truncus arteriosus. Further investigation displayed the reduced p-Akt and p-Erk immunostaining, and the decreased Bmp2 and Bmp4 transcription in the endothelium of Wnt1-cre; Rosa26R-Fgf8 truncus arteriosus. Our findings suggested that Fgf8 over-expression in cardiac neural crest impaired the formation of aorticopulmonary septum by suppressing the endothelial differentiation and stimulating the proliferation of endocardial cushion cells, which implicated a novel etiology of persistent truncus arteriosus.

Reprogramming Axial Level Identity to Rescue Neural-Crest-Related Congenital Heart Defects.

The cardiac neural crest arises in the hindbrain, then migrates to the heart and contributes to critical structures, including the outflow tract septum. Chick cardiac crest ablation results in failure of this septation, phenocopying the human heart defect persistent truncus arteriosus (PTA), which trunk neural crest fails to rescue. Here, we probe the molecular mechanisms underlying the cardiac crest's unique potential. Transcriptional profiling identified cardiac-crest-specific transcription factors, with single-cell RNA sequencing revealing surprising heterogeneity, including an ectomesenchymal subpopulation within the early migrating population. Loss-of-function analyses uncovered a transcriptional subcircuit, comprised of Tgif1, Ets1, and Sox8, critical for cardiac neural crest and heart development. Importantly, ectopic expression of this subcircuit was sufficient to imbue trunk crest with the ability to rescue PTA after cardiac crest ablation. Together, our results reveal a transcriptional program sufficient to confer cardiac potential onto trunk neural crest cells, thus implicating new genes in cardiovascular birth defects.

Surgical repair for persistent truncus arteriosus in neonates and older children.

OBJECTIVES: Persistent truncus arteriosus represents less than 3% of all congenital heart defects. We aim to analyze mid-term outcomes after primary Truncus arteriosus repair at different ages and to identify the risk factors contributing to mortality and the need for intervention after surgical repair. METHODS: This retrospective cohort study included 36 children, underwent repair of Truncus arteriosus in the period from January 2011 to December 2018 in two institutions. We recorded the clinical and echocardiographic data for the patients preoperatively, early postoperative, 6 months postoperative, then every year until their last documented follow-up appointment. RESULTS: Thirty-six patients had truncus arteriosus repair during the study period. Thirty-one patients had open sternum post-repair, and two patients required extracorporeal membrane oxygenation. Bleeding occurred in 15 patients (41.67%), and operative mortality occurred in 5 patients (14.7%). Patients with truncus arteriosus type 2 (p = 0.008) and 3 (p = 0.001) and who were ventilated preoperatively (p < 0.001) had a longer hospital stay. Surgical re-intervention was required in 8 patients (22.86%), and 11 patients (30.56%) had catheter-based reintervention. Freedom from reintervention was 86% at 1 year, 75% at 2 years and 65% at 3 years. Survival at 1 year was 81% and at 3 years was 76%. High postoperative inotropic score predicted mortality (p = 0.013). CONCLUSION: Repair of the truncus arteriosus can be performed safely with low morbidity and mortality, both in neonates, infants, and older children. Re-intervention is common, preferably through a transcatheter approach.

Is two-staged repair for truncus arteriosus type A3 unpractical?

BACKGROUND: A complex and rare form of persistent truncus arteriosus needs careful attention when choosing the optimal strategy for repair. AIM OF THE STUDY: We herein describe our surgical strategy of a small infant having this malformation concomitantly with right aortic arch, unusual pulmonary artery branching and a left superior vena cava. METHODS: The patient underwent initially bilateral pulmonary arterial banding followed by the Rastelli type definitive repair. The pulmonary arteries were unified in front of the left superior vena cava, and the right ventricular outflow tract was readily reconstructed. RESULTS: The patient is doing well with an excellent hemodynamic status. CONCLUSIONS: We considered the two-stage approach was sensible in this particular patient.

Inositol 1,4,5-trisphosphate receptor 2 as a novel marker of vasculature to delineate processes of cardiopulmonary development.

Congenital heart diseases (CHDs) involving the outflow tract (OFT), such as persistent truncus arteriosus (PTA), lead to mortality and morbidity with implications not only in the heart, but also in the pulmonary vasculature. The mechanisms of pulmonary artery (PA) development and the etiologies underlying PA disorders associated with CHD remain poorly understood partly because of a specific marker for PA development is nonexistent. The three subtypes of inositol 1,4,5-trisphosphate receptors (IP3R1, 2, and 3) are intracellular Ca2+ channels that are essential for many tissues and organs. We discovered that IP3R2 was expressed in the vasculature and heart during development using transgenic mice, in which a LacZ marker gene was knocked into the IP3R2 locus. Whole-mount and section LacZ staining showed that IP3R2-LacZ-positive cells were detectable exclusively in the smooth muscle cells, or tunica media, of PA, merging into αSMA-positive cells during development. Furthermore, our analyses suggested that IP3R2-LacZ positive PA smooth muscle layers gradually elongate from the central PA to the peripheral PAs from E13.5 to E18.5, supporting the distal angiogenesis theory for the development of PA, whereas IP3R2-LacZ was rarely expressed in smooth muscle cells in the pulmonary trunk. Crossing IP3R-LacZ mice with mice hypomorphic for Tbx1 alleles revealed that PTA of Tbx1 mutants may result from agenesis or hypoplasia of the pulmonary trunk; thus, the left and right central to peripheral PAs connect directly to the dorsal side of the truncus arteriosus in these mutants. Additionally, we found hypercellular interstitial mesenchyme and delayed maturation of the lung endoderm in the Tbx1 mutant lungs. Our study identifies IP3R2 as a novel marker for clear visualization of PA during development and can be utilized for studying cardiopulmonary development and disease.

Challenges with Managing Delayed Presentation of Persistent Truncus Arteriosus with Torrential Pulmonary Blood Flow in a Resource-Limited Setting.

Embryologically, incomplete conotruncal septation with resultant single aortopulmonary trunk and defective ventricular septation defines the congenital cardiac lesion known as persistent truncus arteriosus (PTA). Torrential pulmonary blood flow is inevitable when this rare lesion is further compounded by patency of the arterial ductus. Such was the case of a patient who presented with fast breathing, reduced suck, darkening of the tongue, and extremities. Urgent echocardiographic diagnosis was PTA (Type A1) with patent ductus arteriosus and pulmonary hypertension and left ventricular systolic dysfunction.

Successful Truncal Valve Replacement After Truncal Valve Repairs.

The surgical management of severe truncal valvular dysfunction is still challenging in neonates with persistent truncus arteriosus. This report describes a 14-day-old neonate with severe truncal valve insufficiency successfully undergoing truncal valve repairs, and followed by valve replacement at the age of 4 years. The truncal valve was quadricuspid with two large and two small leaflets, and all leaflets had severe dysplastic and myxomatous changes. We performed leaflet extension and bicuspidization valvuloplasty for this valve. This patient obtained somatic growth for 4 years without heart failure symptoms, and safely underwent prosthetic valve replacement. This technique would be effective for truncal valve dysfunction in neonates as the life-saving and the bridging procedure to valve replacement.

Anomalous origin of left vertebral artery from ascending aorta associated with interrupted aortic arch and persistent truncus arteriosus.

We present a case of a 3-week-old boy with persistent truncus arteriosus associated with interrupted right aortic arch having an anomalous origin of the left vertebral artery from the ascending aorta.

Persistent truncus arteriosus with absent semilunar valve in first trimester.

Persistent truncus arteriosus (PTA) is a relatively uncommon congenital heart disease, accounting for approximately 0.7-1.4% of all congenital cardiac abnormalities worldwide. PTA is usually accompanied by a single semilunar valve, with leaflets ranging from one to six in number. However, absent semilunar valve (ASV) is rarely seen in PTA. Here, we report a case of prenatally diagnosed PTA accompanied by ASV (PTA-ASV) confirmed by postmortem autopsy.

Early- and mid-term outcomes of surgical repair of persistent truncus arteriosus in children / 中国胸心血管外科临床杂志

@#Objective To evaluate the early- and mid-term outcomes of surgical repair of persistent truncus arteriosus in children in a single institution of China. Methods The clinical data of 27 consecutive patients with persistent truncus arteriosus undergoing surgical repair in Guangzhou Women and Children’s Medical Center from November 2009 to May 2018 were retrospectively reviewed. There were 14 males and 13 females. Median age was 3.0 months (range: 13 days -11 years), of whom 10 (37.0%) were older than 6 months. Results There were three early deaths with a mortality of 11.1%. The main complications included VSD partial repair in 2 patients, complete atrioventricular block in one patient. The mean follow-up time was 24.5±19.3 months (range: 1–76 months). There were three late deaths, and two patients lost follow. Echocardiology showed seven patients of right heart outflow tract obstruction, including three in pulmonary artery trunk, and four of pulmonary artery branches. One patient showed moderate aortic valve regurgitation. None required re-intervention during the follow-up. Survival estimates for the entire cohort following surgery were both 76.1% (95%CI 59.2% to 92.9%) at 1 year and 5 years. Conclusion The surgical repair of persistent truncus arteriosus (PTA) remains challenges. The early- and mid-term outcomes of surgical repair of persistent truncus arteriosus are acceptable. For older children with severe pulmonary artery hypertension and/or trunk valve regurgitation, the risk of death is still higher. Some children have the higher risk of late right heart obstructive lesions.

Foxc2 is required for proper cardiac neural crest cell migration, outflow tract septation, and ventricle expansion.

BACKGROUND: Proper development of the great vessels of the heart and septation of the cardiac outflow tract requires cardiac neural crest cells. These cells give rise to the parasympathetic cardiac ganglia, the smooth muscle layer of the great vessels, some cardiomyocytes, and the conotruncal cushions and aorticopulmonary septum of the outflow tract. Ablation of cardiac neural crest cells results in defective patterning of each of these structures. Previous studies have shown that targeted deletion of the forkhead transcription factor C2 (Foxc2), results in cardiac phenotypes similar to that derived from cardiac neural crest cell ablation. RESULTS: We report that Foxc2-/- embryos on the 129s6/SvEv inbred genetic background display persistent truncus arteriosus and hypoplastic ventricles before embryonic lethality. Foxc2 loss-of-function resulted in perturbed cardiac neural crest cell migration and their reduced contribution to the outflow tract as evidenced by lineage tracing analyses together with perturbed expression of the neural crest cell markers Sox10 and Crabp1. Foxc2 loss-of-function also resulted in alterations in PlexinD1, Twist1, PECAM1, and Hand1/2 expression in association with vascular and ventricular defects. CONCLUSIONS: Our data indicate Foxc2 is required for proper migration of cardiac neural crest cells, septation of the outflow tract, and development of the ventricles. Developmental Dynamics 247:1286-1296, 2018. © 2018 Wiley Periodicals, Inc.

Outcomes of Right Ventricular Outflow Tract Reconstruction for Children with Persistent Truncus Arteriosus: A 10-Year Single-Center Experience.

The purpose of this report is to assess the mid- and long-term outcomes of right ventricular outflow tract (RVOT) reconstruction for children with persistent truncus arteriosus. Between September 2006 and 2016, 105 patients with persistent truncus arteriosus (PTA) received surgical treatment at Shanghai Children's Medical Center. Direct right ventricle-pulmonary artery anastomosis (pulmonary artery pull-down) was performed in 51 patients; a left auricle or pericardial conduit was inserted between the RVOT and pulmonary artery as a connection in 17 patients; heterograft (bovine jugular vein or Gore-tex) conduits and homograft conduits were used in 30 and 7 cases, respectively, to connect the distal pulmonary and right ventricle outflow tract; and pulmonary valve reconstruction was performed in 38 patients using a Gore-tex monocusp. There were six in-hospital deaths and one delayed death 5 months after operation. After a mean follow-up of 55.8 ± 16.5 months (6-113 months), 19 patients underwent reoperation (3 with pulmonary patch enlargement, 14 with conduit replacement and 2 with aortic valve replacement) 10-89 months after the first operation, with 1 hospital death. The actuarial survival rates were 94.2, 93.3 and 93.3% at 1, 5 and 10 years, respectively. Freedom from reoperation was 98.0, 87.8 and 82.7% at 1, 5 and 10 years, respectively. The follow-up variables included echocardiography, chest radiography, cardiac CT and cardiac function. At the last examination, most of the patients exhibited an improvement of New York Heart Association functional class from III or IV preoperatively to I or II at follow-up. Surgical treatment for PTA has an acceptable survival rate and satisfactory outcomes. Most patients exhibited an improvement in cardiac function during follow-up. Aortic arch deformity, truncal valvular regurgitation and long cardiopulmonary bypass time were regarded as risk factors for hospital mortality. Autologous tissue has a lower reoperation rate and better growth potential than extracardiac conduits. A monocusp valve effectively reduces pulmonary regurgitation in the early postoperative stage.

Temporally Distinct Six2-Positive Second Heart Field Progenitors Regulate Mammalian Heart Development and Disease.

The embryonic process of forming a complex structure such as the heart remains poorly understood. Here, we show that Six2 marks a dynamic subset of second heart field progenitors. Six2-positive (Six2+) progenitors are rapidly recruited and assigned, and their descendants are allocated successively to regions of the heart from the right ventricle (RV) to the pulmonary trunk. Global ablation of Six2+ progenitors resulted in RV hypoplasia and pulmonary atresia. An early stage-specific ablation of a small subset of Six2+ progenitors did not cause any apparent structural defect at birth but rather resulted in adult-onset cardiac hypertrophy and dysfunction. Furthermore, Six2 expression depends in part on Shh signaling, and Shh deletion resulted in severe deficiency of Six2+ progenitors. Collectively, these findings unveil the chronological features of cardiogenesis, in which the mammalian heart is built sequentially by temporally distinct populations of cardiac progenitors, and provide insights into late-onset congenital heart disease.