Human Genetics of Truncus Arteriosus.

Integrated human genetics and molecular/developmental biology studies have revealed that truncus arteriosus is highly associated with 22q11.2 deletion syndrome. Other congenital malformation syndromes and variants in genes encoding TBX, GATA, and NKX transcription factors and some signaling proteins have also been reported as its etiology.

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.

Clinical Presentation and Therapy of Truncus Arteriosus.

Truncus arteriosus (TA, also known as common arterial trunk) consists of only one great artery ("the truncus") with a semilunar valve (truncus valve) arising from the heart and an additional ventricular septal defect and (Fig. 50.1). This great artery is positioned above the ventricular septal defect and gives rise to the coronary arteries, the pulmonary arteries, and the aortic arch. Historically, TA has been classified by Collet and Edwards in three types, where in type I there was a common pulmonary artery truncus, in type II the left and right PA arise separately but close to each other, in type III both PA arise independently; in addition, there was a type IV that was later characterized as pulmonary atresia with VSD and major aortopulmonary collateral arteries arising from the descending aorta.

Adult Female Patient with Untreated Truncus Arteriosus Type I and Torsion of Small Bowel Gastrointestinal Stromal Tumor: A Rare Case Report.

BACKGROUND Persistent truncus arteriosus is a rare congenital cyanotic heart defect characterized by a single ventricular outflow tract. Without surgical intervention, it has a poor prognosis in infancy. Here, we report an adult female patient with uncorrected truncus arteriosus type I, who presented with acute-onset abdominal pain due to torsion of a small bowel gastrointestinal stromal tumor (GIST). CASE REPORT A 41-year-old woman came to our Emergency Department with acute-onset lower abdominal pain for 2 days. Congenital heart disease, truncus arteriosus, had been diagnosed at birth, and there had been no surgical intervention. Abdominal computed tomography revealed a 10×9×12-cm mixed-density mass in the pelvic capacity. Transthoracic echocardiography revealed a 33-mm ventricular septal defect. The ascending aorta originated mainly from the right ventricle, and the pulmonary artery originated from the beginning of the aorta (type I truncus arteriosus, according to Collett and Edwards classification). After a quick and detailed preoperative workup, the patient underwent tumor resection by open surgery with general anesthesia. CONCLUSIONS This is the first case to report emergency surgery for a patient with uncorrected persistent truncus arteriosus due to torsion of a small bowel GIST. A multidisciplinary team with deep understanding of the disease entity was crucial. By considering the fixed hemodynamic and respiratory physiology, overtreatment and unrealistic goals were avoided. Eventually, the patient was discharged after being hospitalized for 2 weeks.

Successful Late Repair of Truncus Arteriosus: A Single Center Experience.

Background: Truncus arteriosus is a rare congenital heart defect resulting from the failure of the truncus arteriosus to divide during fetal development. It leads to a single outflow tract from the heart and, if left untreated, can be fatal. Late presentation and repair can also increase the risk of pulmonary hypertensive crises, which can lead to morbidity and mortality after repair. Methods: We performed a retrospective study examining outcomes of late-presenting patients who were repaired for this anomaly at our institution. Results: We identified seven patients who underwent late repair of truncus arteriosus who were 3 to 11 years of age. There were six females and one male. Postoperatively, all patients showed improvement in symptoms and hemodynamic parameters, with no reported mortality. The median duration of stay in the intensive care unit was nine days and with a range from 3 to 18 days, while the median hospital stay was 29 days with a range from 21 to 60 days. Conclusion: These findings highlight the potential for successful outcomes even in cases of delayed diagnosis.

Partial Heart Transplant in a Neonate With Irreparable Truncal Valve Dysfunction.

Importance: The treatment of neonates with irreparable heart valve dysfunction remains an unsolved problem because there are no heart valve implants that grow. Therefore, neonates with heart valve implants are committed to recurrent implant exchanges until an adult-sized valve can fit. Objective: To deliver the first heart valve implant that grows. Design, Setting, and Participants: Case report from a pediatric referral center, with follow-up for more than 1 year. Participants were a recipient neonate with persistent truncus arteriosus and irreparable truncal valve dysfunction and a donor neonate with hypoxic-ischemic brain injury. Intervention: First-in-human transplant of the part of the heart containing the aortic and pulmonary valves. Main Outcomes and Measures: Transplanted valve growth and hemodynamic function. Results: Echocardiography demonstrated adaptive growth and excellent hemodynamic function of the partial heart transplant valves. Conclusions and Relevance: In this child, partial heart transplant delivered growing heart valve implants with a good outcome at age 1 year. Partial heart transplants may improve the treatment of neonates with irreparable heart valve dysfunction.

Novel pathogenic GATA6 variant associated with congenital heart disease, diabetes mellitus and necrotizing enterocolitis.

BACKGROUND: Pathogenic GATA6 variants have been associated with congenital heart disease (CHD) and a spectrum of extracardiac abnormalities, including pancreatic agenesis, congenital diaphragmatic hernia, and developmental delay. However, the comprehensive genotype-phenotype correlation of pathogenic GATA6 variation in humans remains to be fully understood. METHODS: Exome sequencing was performed in a family where four members had CHD. In vitro functional analysis of the GATA6 variant was performed using immunofluorescence, western blot, and dual-luciferase reporter assay. RESULTS: A novel, heterozygous missense variant in GATA6 (c.1403 G > A; p.Cys468Tyr) segregated with affected members in a family with CHD, including three with persistent truncus arteriosus. In addition, one member had childhood onset diabetes mellitus (DM), and another had necrotizing enterocolitis (NEC) with intestinal perforation. The p.Cys468Tyr variant was located in the c-terminal zinc finger domain encoded by exon 4. The mutant protein demonstrated an abnormal nuclear localization pattern with protein aggregation and decreased transcriptional activity. CONCLUSIONS: We report a novel, familial GATA6 likely pathogenic variant associated with CHD, DM, and NEC with intestinal perforation. These findings expand the phenotypic spectrum of pathologic GATA6 variation to include intestinal abnormalities. IMPACT: Exome sequencing identified a novel heterozygous GATA6 variant (p.Cys468Tyr) that segregated in a family with CHD including persistent truncus arteriosus, atrial septal defects and bicuspid aortic valve. Additionally, affected members displayed extracardiac findings including childhood-onset diabetes mellitus, and uniquely, necrotizing enterocolitis with intestinal perforation in the first four days of life. In vitro functional assays demonstrated that GATA6 p.Cys468Tyr variant leads to cellular localization defects and decreased transactivation activity. This work supports the importance of GATA6 as a causative gene for CHD and expands the phenotypic spectrum of pathogenic GATA6 variation, highlighting neonatal intestinal perforation as a novel extracardiac phenotype.

Patent ductus arteriosus stenting as therapeutic bridge in a patient with type A3 truncus arteriosus variant with multiple comorbidities.

Type A3 truncus arteriosus describes pulmonary atresia with non-confluent mediastinal pulmonary arteries in which one pulmonary artery arises from a patent ductus arteriosus and the contralateral pulmonary artery from the aorta resulting in ductal dependent pulmonary blood flow. We describe a premature neonate with caudal regression syndrome and type A3 truncus arteriosus who was palliated with a ductal stent allowing completion of a prolonged neonatal ICU hospitalisation for multiple comorbidities.

Survival After Single-Stage Repair of Truncus Arteriosus and Associated Defects.

BACKGROUND: The goal of this study was to describe in-hospital and long-term mortality after single-stage repair of truncus arteriosus communis (TAC) and explore factors associated with these outcomes. METHODS: This was a cohort study of consecutive patients undergoing single-stage TAC repair between 1982 and 2011 reported to the Pediatric Cardiac Care Consortium registry. In-hospital mortality was obtained for the entire cohort from registry records. Long-term mortality was obtained for patients with available identifiers by matching with the National Death Index through 2020. Kaplan-Meier survival estimates were created for up to 30 years after discharge. Cox regression models estimated hazard ratios for the associations with potential risk factors. RESULTS: A total of 647 patients (51% male) underwent single-stage TAC repair at a median age of 18 days; 53% had type I TAC, 13% had interrupted aortic arch, and 10% underwent concomitant truncal valve surgery. Of these, 486 (75%) patients survived to hospital discharge. After discharge, 215 patients had identifiers for tracking long-term outcomes; 30-year survival was 78%. Concomitant truncal valve surgery at the index procedure was associated with increased in-hospital and 30-year mortality. Concomitant interrupted aortic arch repair was not associated with increased in-hospital or 30-year mortality. CONCLUSIONS: Concomitant truncal valve surgery but not interrupted aortic arch was associated with higher in-hospital and long-term mortality. Careful consideration of the need and timing for truncal valve intervention may improve TAC outcomes.

Truncal valve repair in an adolescent with severe annular dilatation.

Approximately 20% of patients with truncus arteriosus might need a truncal valve procedure within 20 years after anatomical repair due to regurgitation. These patients commonly develop valve regurgitation due to root dilatation with a sufficient amount of good quality valvular tissue. Thus, the reduction of the truncal annulus is the single most important factor to achieve durable repair, especially in patients in whom the Ross procedure is not an option.

Echocardiography: conotruncal anomaly: a case of common arterial trunk with intact ventricular septum and hypoplastic left heart complex with unbalanced pulmonary stenoses.

We describe the echocardiographic findings of a common arterial trunk with intact ventricular septum, mitral and left ventricular hypoplasia, atretic left ventricular outlet and bilateral, and unbalanced pulmonary artery stenoses.

Outcomes in Primary Repair of Truncus Arteriosus with Significant Truncal Valve Insufficiency: A Systematic Review and Meta-analysis.

Data regarding the effect of significant TVI on outcomes after truncus arteriosus (TA) repair are limited. The aim of this meta-analysis was to summarize outcomes among patients aged ≤ 24 months undergoing TA repair with at least moderate TVI. A systematic literature search was conducted in PubMed, Scopus, and CINAHL Complete from database inception through June 1, 2022. Studies reporting outcomes of TA repair in patients with moderate or greater TVI were included. Studies reporting outcomes only for patients aged > 24 months were excluded. The primary outcome was overall mortality, and secondary outcomes included early mortality and truncal valve reoperation. Random-effects models were used to estimate pooled effects. Assessment for bias was performed using funnel plots and Egger's tests. Twenty-two single-center observational studies were included for analysis, representing 1,172 patients. Of these, 232 (19.8%) had moderate or greater TVI. Meta-analysis demonstrated a pooled overall mortality of 28.0% after TA repair among patients with significant TVI with a relative risk of 1.70 (95% CI [1.27-2.28], p < 0.001) compared to patients without TVI. Significant TVI was also significantly associated with an increased risk for early mortality (RR 2.04; 95% CI [1.36-3.06], p < 0.001) and truncal valve reoperation (RR 3.90; 95% CI [1.40-10.90], p = 0.010). Moderate or greater TVI before TA repair is associated with an increased risk for mortality and truncal valve reoperation. Management of TVI in patients remains a challenging clinical problem. Further investigation is needed to assess the risk of concomitant truncal valve surgery with TA repair in this population.

Transapical Delivery of a Sapien Valve for Transcatheter Aortic Valve Replacement in an 11-Year-Old Patient with Truncus Arteriosus.

Complex congenital heart defects may necessitate repeated surgical interventions throughout a patient's lifetime. Each subsequent procedure exposes patients to a greater cumulative risk, thus adding to the potential morbidity and mortality of the surgery. Transcatheter interventions can help mitigate the surgical risk for many defects and can delay or mitigate the need for surgery. This case report describes the rare use of a transapically delivered transcatheter aortic valve replacement (TAVR) therapy in a high-risk pediatric patient to postpone the need for surgery and potentially reduce the number of lifelong surgical interventions. The case highlights how transcatheter aortic valve therapies can be considered for non-standard, higher risk pediatric patients to postpone the need for surgical valve replacement and may serve as a paradigm shift in the care of complex patients with aortic valve pathology.

Atrioventricular dissociation in a cat with persistent truncus arteriosus.

A 10-month-old female domestic shorthaired (DSH) cat was presented with peracute respiratory problems. Physical examination revealed dyspnoea, tachypnoea, cyanosis, weak pulse and bradycardia. Auscultation showed pulmonary crepitation and attenuated heart sounds and a pansystolic grade V/VI murmur. The electrocardiogram showed atrioventricular dissociation identified as third-degree sinoatrial block. X-rays showed increased density in the ventral and middle zones of the thorax and loss of definition of the cardiac silhouette and increased diffuse radiographic density of the entire abdomen. Echocardiography revealed dilatation of the right atrium and concentric biventricular hypertrophy. A type 1 persistent truncus arteriosus was diagnosed at necropsy. This is the first case report of this type of arrhythmia in a cat with persistent truncus arteriosus, and its relationship with the described congenital cardiac anomaly is discussed.

Natural History of Truncal Root Dilatation and Truncal Valve Regurgitation in Truncus Arteriosus.

BACKGROUND: The natural history of the dilated truncal root in repaired truncus arteriosus (TA) is incompletely understood. METHODS: A single-center review of patients who underwent TA repair between January 1984 and December 2018 was performed. Echocardiographically determined root diameters and derived z scores were measured at the annulus, sinus of Valsalva (SoV), and sinutubular junction (STJ) immediately before TA repair and throughout follow-up. Linear mixed-effects models assessed trends in root dimensions over time. RESULTS: Of 193 patients who underwent TA repair at a median age of 12 days (interquartile range, 6-48 days) and survived to discharge, 34 (17.6%), 110 (57.0%), and 49 (25.4%) patients had bicuspid, tricuspid, and quadricuspid truncal valves, respectively. Median postoperative follow-up was 11.6 years (interquartile range, 4.4-22.0 years; range, 0.1-34.8 years). Truncal valve or root intervention was required in 38 patients (19.7%). The mean rates of annular, SoV, and STJ growth were 0.7 ± 0.3 mm/y, 0.8 ± 0.5 mm/y, and 0.9 ± 0.4 mm/y, respectively. Root z scores remained stable with time. At baseline, compared with patients with tricuspid leaflet anatomy, bicuspid patients had larger diameters at the SoV (P = .003) and STJ (P = .029), whereas quadricuspid patients had larger STJ diameters (P = .004). Over time, the bicuspid and quadricuspid cohorts demonstrated comparatively greater annular dilatation (both P < .05). Patients with ≥75th percentile root growth rates had a higher incidence of moderate-severe truncal regurgitation (P = .019) and truncal valve intervention (P = .002). CONCLUSIONS: Root dilatation in TA persisted for up to 30 years after primary repair. Patients with bicuspid and quadricuspid truncal valves demonstrated greater root dilatation over time and required more valve interventions. Continued longitudinal follow-up is warranted in this higher-risk cohort.

Surgical Repair of a Rare Variant of Common Arterial Trunk, With Considerations of its Significance for Morphogenesis.

We present a successful surgical repair of a rare variant of the common arterial trunk with unusual arrangement of the pulmonary arteries. The variant was not readily classified using either of the popular classifications for the common arterial trunk. It is appropriately described as a common arterial trunk showing aortic dominance, but with extrapericardial origin of the pulmonary arteries from the underside of the truncal arch. We also provide an account of cardiac development, which we suggest offers an accurate explanation for its morphogenesis.