Tetralogy of Fallot: Yesterday and Today

Integrative metabolomics dictate distinctive signature profiles in patients with Tetralogy of Fallot

BACKGROUND

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease (CCHD) with multifactorial etiology. We aimed to investigate the metabolic profiles of CCHD and their independent contributions to TOF.

METHODS

A cohort comprising 42 individuals with TOF and atrial septal defect (ASD) was enrolled. Targeted ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was employed to systematically analyze metabolite levels and identify TOF-associated metabolic profiles.

RESULTS

Of 370 identified metabolites in tissue and 284 in plasma, over one-third of metabolites showed an association with microbiome. Differential metabolic pathways including amino acids biosynthesis, ABC (ATP-binding cassette) transporters, carbon metabolism, and fatty acid biosynthesis, shed light on TOF biological phenotypes. Additionally, ROC curves identified potential biomarkers, such as erythronic acid with an AUC of 0.868 in plasma, and 3-β-hydroxy-bisnor-5-cholenic acid, isocitric acid, glutaric acid, ortho-Hydroxyphenylacetic acid, picolinic acid with AUC close to 1 in tissue, whereas the discriminative performance of those substances significantly improved when combined with clinical phenotypes.

CONCLUSIONS

Distinct metabolic profiles exhibited robust discriminatory capabilities, effectively distinguishing TOF from ASD patients. These metabolites may serve as biomarkers or key molecular players in the intricate metabolic pathways involved in CCHD development.

IMPACT

Distinct metabolic profiles exhibited robust discriminatory capabilities, effectively distinguishing Tetralogy of Fallot from atrial septal defect patients. Similar profiling but inconsistent differential pathways between plasma and tissue. More than one-third metabolites in plasma and tissue are associated with the microbiome. The discovery of biomarkers is instrumental in facilitating early detection and diagnosis of Tetralogy of Fallot. Disturbed metabolism offers insights into interpretation of pathogenesis of Tetralogy of Fallot.

Total Correction for Tetralogy of Fallot in Patients Weighing Over 10 kg: Experiences and Follow-Up Outcomes

Background Although the recommended time for total correction of tetralogy of Fallot (TOF) is during infancy, sometimes TOF cases present to healthcare setups after pre-school age, with some cases presenting even beyond adolescence in developing countries. The objective of this study was to assess patients with TOF weighing 10 kg and above who underwent definitive corrective surgical techniques such as transannular patch (TAP), valve-sparing right ventricular outflow tract (RVOT) pericardial patch augmentation, non-ventriculotomy infundibular resection for postoperative complications, hospital stay, and right ventricular (RV) dysfunction in the immediate postoperative period and subsequent outpatient department follow-ups. Methodology This comprehensive, retrospective cohort study included single-center data collected between January 16, 2018, and January 15, 2024. The study included 63 patients diagnosed with TOF weighing 10 kg and above, ensuring a robust and representative sample. Results Of the 119 patients who underwent total correction for TOF, 63 met the study's inclusion criteria of TOF weighing above 10 kg. Of the 63 patients, 55.6% were males, and 44.4% were females. The mean weight of the study participants was 33.4 kg. The mean age was 15.9 years. Of the 63 patients, 39 underwent TAP surgery, 18 underwent RVOT patch augmentation, and six underwent total correction by non-ventriculotomy infundibular resection. There was a significant difference between the type of surgery groups and RV dysfunction, with the TAP group showing a higher incidence of RV dysfunction, indicating a potential risk factor associated with this technique. Conclusions Although TAP has significant immediate postoperative complications compared to other techniques, its long-term follow-up suggests that long-term survival and quality of life, as measured by major adverse cardiac events such as heart failure, arrhythmias, and reoperation rates, are commensurable in adulthood. This indicates that despite the initial challenges, TAP can provide satisfactory outcomes in the long run.

Pulmonary and tricuspid regurgitation after Tetralogy of Fallot repair: A case report

BACKGROUND

Tetralogy of Fallot (TOF) is one of the most common congenital heart defects, and surgery is the primary treatment. There are no precise guidelines on the treatment protocol for tricuspid regurgitation (TR) as a common complication of TOF repair. The timing for treatment in patients presenting with valve regurgitation after TOF repair is often difficult to determine. Here, we report the first case of sequential treatment of pulmonary and TR using interventional therapy.

CASE SUMMARY

We present the case of a 52-year-old female patient, who had a history of TOF repair at a young age. A few years later, the patient presented with pulmonary and tricuspid regurgitation. The symptoms persisted and TR worsened following percutaneous pulmonary valve implantation. Preoperative testing revealed that the patient's disease had advanced to an intermediate to advanced stage and that her general health was precarious. Because open-heart surgery was not an option for the patient, transcatheter tricuspid valve replacement was suggested. This procedure was successful, and the patient recovered fully without any adverse effects. This case report may serve as a useful resource for planning future treatments.

CONCLUSION

Treatment of both valves should be considered in patients with tricuspid and pulmonary regurgitations following TOF repair. The interventional strategy could be an alternative for patients with poor general health.

Tetralogy of Fallot: variants of MYH6 gene promoter and cellular functional analyses

BACKGROUND

Tetralogy of Fallot (TOF) is a common form of congenital heart disease. The MYH6 gene has important effects on cardiovascular growth and development.

METHODS

In 608 subjects, including 315 TOF patients, we investigated the MYH6 gene promoter variants and verified the effect on gene expression by using cellular functional experiments with three cell lines (HEK-293, HL-1, and H9C2 cells) and bioinformatics analysis.

RESULTS

In the MYH6 gene promoter, 12 variants were identified from 608 subjects. Five variants were found only in patients with TOF and two of them (g.3384G>T and g.4518T>C) were novel. Electrophoretic mobility shift assay with three cell lines (HEK-293, HL-1, and H9C2) showed significant changes in the transcription factors bound by the promoter variants compared to the wild-type. Dual luciferase reporter showed that four of the five variants reduced the transcriptional activity of the MYH6 gene promoter (p < 0.05).

CONCLUSIONS

This study is the first to test the cellular function of variants in the promoter region of the MYH6 gene in patients with TOF, which provides new insights into the genetic basis of TOF and provides a basis for further study of the mechanism of TOF formation.

IMPACT

DNA from 608 human subjects was sequenced for MYH6 gene promoter region variants with five variants found only in TOF patients and two were novel. EMSA and dual luciferase reporter experiments in three cell lines found these variants pathological. Prediction by JASPAR database indicated that these variants alter the transcription factor binding sites. The study, for the first time, confirmed that there are variants at the MYH6 gene promoter region and these variants alter the cellular function. The variants found in this study suggest the possible pathological role in the formation of TOF.

Treating Tet Spells With Disopyramide in a 72-Year-Old Awaiting Primary Repair of Tetralogy of Fallot

An adult with unrepaired tetralogy of Fallot presented with frequent tet spells. Her course was complicated by severe cyanotic spells and tachycardia-bradycardia syndrome that limited beta blocker use to stabilize her spells. She markedly improved after disopyramide initiation and underwent successful tetralogy of Fallot repair with excellent functional outcome.

The Nakata index and McGoon ratio: correlation with the severity of pulmonary regurgitation after the repair of paediatric tetralogy of Fallot

BACKGROUND

Pulmonary regurgitation is the most common complication after the complete repair of tetralogy of Fallot, and severe pulmonary regurgitation after surgery requires pulmonary valve replacement. In this retrospective observational, cross-sectional study, we included a total of 56 children aged 6 years or younger who underwent complete repair of TOF at Shahid Rajaei Cardiovascular Medical and Research Center in Tehran, Iran. Preoperative dual-source computed tomography was used to measure the McGoon ratio and Nakata index. The patients were divided into two groups based on the severity of postoperative pulmonary regurgitation, as estimated by trans-thoracic echocardiography: the severe pulmonary regurgitation group and the non-severe pulmonary regurgitation group. The McGoon ratio and Nakata index were then compared between the two groups.

RESULTS

When comparing the two groups, we found that the corrected right pulmonary artery diameter, main pulmonary artery diameter, and McGoon ratio in the non-severe pulmonary regurgitation group were higher than in the severe pulmonary regurgitation group. However, none of these differences were statistically significant. Additionally, other variables, including the corrected left pulmonary artery diameter and Nakata index, showed higher measurements in children with severe pulmonary regurgitation, but again, the differences were not statistically significant.

CONCLUSIONS

This study indicates that pulmonary arteries diameter, Nakata index, and McGoon ratio were not significantly correlated with the severity of pulmonary regurgitation after the complete repair of tetralogy of Fallot.

Pulmonary Artery Stenosis in Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the most common cyanotic congenital cardiac defect. The survival rate after primary complete repair is high (98-100%); however, pulmonary artery stenosis (PAS) is not uncommon after TOF repair, and severe PAS aggravates pulmonary regurgitation, resulting in right ventricle dilation, ventricular arrhythmia, and possibly death. PAS in TOF can be congenital due to hypoplasia or coarctation or can be acquired secondary to a surgical procedure. The latter may be caused by an exogenous conduit implant, compression from the adjacent enlarged ascending aorta, or outflow tract dilation after transannular patch repair. PAS can also be caused by the pulmonary artery plasty strategy itself. Here, the intrinsic mechanisms underlying PAS and pulmonary artery plasty techniques and strategies are reviewed to provide guidance for surgeons.

Short-term outcomes following total correction of tetralogy of fallot in adult patients

OBJECTIVES

Tetralogy of Fallot (TOF) is a common congenital heart disease which should be corrected. The recommended time for the Tetralogy of Fallot Total Correction (TFTC) surgery is during the infancy for the possible difficulties during the surgery and the related issues. However, sometimes TOF is diagnosed and managed during the adulthood.

METHODS

This study is a descriptive and retrospective one which included all patients who underwent TFTC at the age of 15-year and older in 10 years (between the years 2010 and 2020) to identify short-term (in-hospital mortality, ICU stay, postoperative bleeding, respiratory complications after the surgery such as pulmonary edema, pneumonia, etc.) and one-year (left ventricle ejection fraction (LVEF), right ventricle (RV) ejection fraction, the severity of tricuspid and aortic regurgitation after surgery) outcomes. All data were taken from medical records at Rajaie Cardiovascular Medical and Research Center. Data were analyzed using SPSS 22.

RESULTS

94 patients with the mean ± SD age of 26.7 ± 9.6 years were enrolled. Most of them were male (59.6%) (P-value: 0.009). In-hospital mortality in our study were 5.3%. Tricuspid regurgitation (TR) was significantly resolved after the surgery (P-value: 0.006). Of 17 (18.1%) patients with small or hypoplastic pulmonary artery (PA) branches, 14 patients had acceptable PA branch size after surgery.

CONCLUSION

TFTC at an older age is safe with acceptable results. Age is not a contraindication for TFTC and surgery should be recommended if the patients are diagnosed with TOF in adulthood. Also, the TOF diagnosis should be considered in adult patients with suspicious signs and symptoms.

Midterm prognosis following total correction of tetralogy of fallot in adult patients

Background

Tetralogy of Fallot is a common congenital heart disease characterized by cyanosis. The primary treatment approach involves corrective surgery typically performed within the first year of life to achieve complete resolution. However, certain patients may undergo surgery at an older age. This study seeks to assess the efficacy of surgery by examining the midterm outcomes of total correction of Tetralogy of Fallot when performed in older individuals.

Methods

This interventional-longitudinal study focused on patients who underwent complete surgery to correct tetralogy of Fallot at an advanced age of over 15 years. All of the participants were referred to the Shahid Rajaei Heart and Vascular Center, which is a referral center for congenital heart diseases in Iran, between 2010 and 2020. The surgical procedures for these patients involved primary total correction of tetralogy of Fallot or surgery following by shunt implantation. Prior to the surgery, the necessary information was gathered from the patients' medical records. The patients were then monitored over a 5-year period, during which they received regular check-ups from cardiologist with fellowship in adult congenital heart disease.

Results

A total of 94 participants were enrolled in the study, with an average age of 26.7 ± 9.6 years. Notably, the majority of the participants were male. The study reported a late mortality rate of 3.2%. Furthermore, 17 patients, constituting 18% of the cohort, underwent a secondary surgical procedure. This secondary surgery encompassed 14 cases of Pulmonary Valve Replacement (14.8%) and 3 cases of Ventricular Septal Defect repair (3.1%).

Conclusion

While the optimal age for total correction of Tetralogy of Fallot is conventionally considered to be within the first year of life, this study demonstrated that surgical intervention performed at a later stage of life can yield favorable midterm prognoses. It is imperative to emphasize that individuals unable to undergo surgery at the ideal age due to a multitude of factors should not be deprived of the potential benefits associated with surgical intervention.

Mutations in genes related to myocyte contraction and ventricular septum development in non-syndromic tetralogy of Fallot

Objective

Eighty percent of patients with a diagnosis of tetralogy of Fallot (TOF) do not have a known genetic etiology or syndrome. We sought to identify key molecular pathways and biological processes that are enriched in non-syndromic TOF, the most common form of cyanotic congenital heart disease, rather than single driver genes to elucidate the pathogenesis of this disease.

Methods

We undertook exome sequencing of 362 probands with non-syndromic TOF and their parents within the Pediatric Cardiac Genomics Consortium (PCGC). We identified rare (minor allele frequency <1 × 10-4), de novo variants to ascertain pathways and processes affected in this population to better understand TOF pathogenesis. Pathways and biological processes enriched in the PCGC TOF cohort were compared to 317 controls without heart defects (and their parents) from the Simons Foundation Autism Research Initiative (SFARI).

Results

A total of 120 variants in 117 genes were identified as most likely to be deleterious, with CHD7, CLUH, UNC13C, and WASHC5 identified in two probands each. Gene ontology analyses of these variants using multiple bioinformatic tools demonstrated significant enrichment in processes including cell cycle progression, chromatin remodeling, myocyte contraction and calcium transport, and development of the ventricular septum and ventricle. There was also a significant enrichment of target genes of SOX9, which is critical in second heart field development and whose loss results in membranous ventricular septal defects related to disruption of the proximal outlet septum. None of these processes was significantly enriched in the SFARI control cohort.

Conclusion

Innate molecular defects in cardiac progenitor cells and genes related to their viability and contractile function appear central to non-syndromic TOF pathogenesis. Future research utilizing our results is likely to have significant implications in stratification of TOF patients and delivery of personalized clinical care.

Genetic Variants of ISL1 Gene Promoter Identified from Congenital Tetralogy of Fallot Patients Alter Cellular Function Forming Disease Basis

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease in newborns. ISL1 is a master transcription factor in second heart field development, whereas the roles of ISL1 gene promoter variants in TOF patients have not been genetically investigated. Total DNA extraction from 601 human subjects, including 308 TOF patients and 293 healthy controls, and Sanger sequencing were performed. Four variants (including one novel heterozygous variant) within the ISL1 gene promoter were only found in TOF patients. Functional analysis of DNA sequence variants was performed by using the dual-luciferase reporter assay and demonstrated that three of the four variants significantly decreased the transcriptional activity of ISL1 gene promoter in HL-1 cells (p < 0.05). Further, the online JASPAR database and electrophoretic mobility shift assay showed that the three variants affected the binding of transcription factors and altered ISL1 expression levels. In conclusion, the current study for the first time demonstrated that the variants identified from the ISL1 gene promoter region are likely involved in the development of TOF by affecting the transcriptional activity and altering the ISL1 expression level. Therefore, these findings may provide new insights into the molecular etiology and potential therapeutic strategy of TOF.

End-diastolic forward flow in repaired tetralogy of Fallot: Mid-term outcomes from a single center

Background

Pulmonary arterial end-diastolic forward flow (EDFF) following repaired tetralogy of Fallot (rTOF) is recognized as right ventricular (RV) restrictive physiology, which is closely related to poor prognosis. This study sought to review mid-term experience and investigate the risk factors of EDFF in the rTOF patients.

Methods

From September 2016 to January 2019, 100 patients (age < 18 years old) who underwent complete tetralogy of Fallot (TOF) repair were enrolled and were divided into EDFF group (n = 52) and non-EDFF group (n = 48) based on the presence of postoperative EDFF. Elastic net analysis was performed for variable selection. Univariate and multivariate logistic analyses were used to analyze the correlation between risk factors and EDFF.

Results

End-diastolic forward flow group had lower systolic blood pressure (P = 0.037), diastolic blood pressure (P = 0.027), and higher vasoactive-inotrope score within 24 h after surgery (P = 0.022) than non-EDFF group. Transannular patch (TAP) was an independent predictor of postoperative EDFF [P = 0.029, OR: 2.585 (1.102∼6.061)]. Patients were followed up for a median of 2.6 years [interquartile range (IQR) 1.6] after the first TOF repair. During follow-up, the prevalence of the EDFF was lower in those with pulmonary valve (PV) reconstructions than that in those undergoing patch enlargement without PV reconstructions in the primary TOF repair (P < 0.001).

Conclusion

End-diastolic forward flow was associated with TAP. Patients with EDFF might have a transient hemodynamic instability in the early postoperative period. PV reconstructions in the TOF repair might reduce the incidence of EDFF in the mid-term follow-up.

The management of newborns with critical congenital heart diseases prior to transport to a cardiac center

Critical congenital heart diseases (CCHD) are important causes of mortality and morbidity in the newborn period. Even after diagnosis, their management could be seriously compromised by the unplanned delivery in hospitals with limited expertise and resources. The newborn may spend days or week before transport putting a significant burden on the neonatal team to manage such challenging diseases. In this review, the management principles of each individual pathology are discussed in the setting before transport to cardiac centers. Understanding these principles will help the treating teams evaluate and manage those complex conditions. The review avoids the advanced discussion on the management of CCHDs not applicable to the pre-transport setup. It highlights the critical elements in the maintenance of normal hemodynamics specific to each pathology and their variation.

Long-Term Results after Fallot Repair

BACKGROUND

 The aim of this study was to evaluate the long-term outcome and freedom from pulmonary valve replacement (PVR) after initial repair of tetralogy of Fallot (TOF).

PATIENTS AND METHODS

 The cohort of 306 patients treated between 1980 and 2017 was divided into anatomical subgroups according to the diagnosis of TOF-pulmonary stenosis, TOF-pulmonary atresia and TOF-double outlet right ventricle. Patients were treated with transannular patch (TAP), valve sparing repair (VSR), or conduits from the right ventricle to the pulmonary arteries (RVPA conduits).

RESULTS

 There were 21 deaths (6.9%), 14 being hospital deaths (4.6%) after primary correction and four deaths (1.3%) occurred after PVR. One patient died after a non-cardiac operation (0.3%). There were two late deaths (0.7%). During the past 12 years no early mortality has been observed. Ninety-one patients (30.4%) received PVR after a median of 12.1 ± 7.0 years with an early mortality of 4.4% (n = 4) and no late mortality. A significant difference in freedom from reoperation after TAP, VSR, and RVPA-conduits could be identified. Multivariate analysis displayed transannular repair (p = 0.016), primary palliation (p <0.001), the presence of major aortopulmonary collateral arteries (MAPCA; p = 0.023), and pulmonary valve Z-scores < - 4.0 (p = 0.040) as significant risk factors for PVR.

CONCLUSION

 TOF repair has a beneficial long-term prognosis with low morbidity and mortality. Pulmonary valve Z-scores < - 4.0, transannular repair, and presence of MAPCAs are associated with earlier PVR. Non-VSRs and TOF-pulmonary atresia lead to earlier reoperation but have no negative impact on survival.

Tissue engineering: Relevance to neonatal congenital heart disease

Congenital heart disease (CHD) represents a large clinical burden, representing the most common cause of birth defect-related death in the newborn. The mainstay of treatment for CHD remains palliative surgery using prosthetic vascular grafts and valves. These devices have limited effectiveness in pediatric patients due to thrombosis, infection, limited endothelialization, and a lack of growth potential. Tissue engineering has shown promise in providing new solutions for pediatric CHD patients through the development of tissue engineered vascular grafts, heart patches, and heart valves. In this review, we examine the current surgical treatments for congenital heart disease and the research being conducted to create tissue engineered products for these patients. While much research remains to be done before tissue engineering becomes a mainstay of clinical treatment for CHD patients, developments have been progressing rapidly towards translation of tissue engineering devices to the clinic.

Chronic hypoxia prolongs postoperative mechanical ventilation and reduces the left atrial pressure threshold in children with tetralogy of Fallot

BACKGROUND

Chronic hypoxia induces pulmonary microvascular endothelial dysfunction. The left atrial pressure (LAP) represents the hydrostatic pressure of pulmonary microcirculation. The conjunction of the LAP and any abnormal pulmonary microvascular endothelial barrier function will have an impact on pulmonary exudation, resulting in prolonged mechanical ventilation. This study aimed to investigate the tolerance threshold of the pulmonary microcirculation to LAP in children with tetralogy of Fallot (TOF) to avoid prolonged mechanical ventilation after surgery.

METHODS

This retrospective study included 297 Chinese patients who underwent TOF correction at Fuwai Hospital. Patients were categorized according to their preoperative oxygen saturation (SpO₂) level. One-to-one propensity score matching (PSM) revealed a total of 126 participants in the SpO₂< 90% and SpO₂≥ 90% groups. Between-group comparisons were conducted to verify the correlation between hypoxia and prolonged mechanical ventilation. A subgroup analysis was performed to reveal the significant role of postoperative LAP stewardship on prolonged mechanical ventilation.

RESULTS

Failure to extubate within the first 48 h (23.81% vs. 9.52%, P = 0.031) and prolonged mechanical ventilation (26.98% vs. 11.11%, P = 0.023) were more commonly observed in children with preoperative SpO₂ < 90%. The incidence of prolonged mechanical ventilation consistently increased with LAP in both the SpO₂ < 90% and SpO₂ ≥ 90% groups, although LAP was still within the normal range (6-12 mmHg). Children in chronic hypoxic conditions tolerated lower LAP well. The tolerance threshold for postoperative LAP in children diagnosed with TOF under chronic hypoxic conditions was identified as 7 mmHg.

CONCLUSIONS

Children in a chronic hypoxic state may suffer from a high incidence of prolonged mechanical ventilation after surgical correction of TOF and may not tolerate higher postoperative LAP. To improve pulmonary prognosis, it is better to control and maintain the postoperative LAP at a lower state (≤7 mmHg) in children with chronic hypoxia.

Differences in Cardiopulmonary Fitness Between Boy and Girls With Repaired Tetralogy of Fallot

OBJECTIVE

Many studies have demonstrated that patients with repaired tetralogy of Fallot (rTOF) have generally poorer cardiopulmonary fitness (CPF). However, little is known about how the disease results in different CPF in each sex. Therefore, this study aimed to investigate whether sex (and gender) differences affect CPF in children and adolescents with rTOF.

METHODS

This retrospective study recruited adolescents and children (aged 10-18) with rTOF following an acute stage of tetralogy of Fallot (TOF) who received cardiopulmonary exercise testing (CPET) in the past 10 years. CPF was determined by symptom-limited CPET with a treadmill under ramped Bruce protocol. Boys and girls were categorized into groups based on body mass index (BMI) and fat mass index (FMI). The BMI was grouped by Taiwanese obesity cutoff points. The FMI was categorized by the body fat percentage. Excess adiposity was defined as (1) "overweight" and "obese" by BMI and (2) greater than the sex- and age-specific 75th percentile of whole subjects by FMI.

RESULTS

A total of 185 participants (104 boys and 81 girls) with rTOF were recruited for the final analysis. Within the BMI category, 76 boys and 63 girls were in the normal group, whereas 28 boys and 18 girls were in the excessive adiposity group. Within the FMI category, 77 boys and 60 girls were in the normal group, whereas 27 boys and 21 girls were in the excessive adiposity group. The analysis of the body composition of rTOF subjects showed that there was no statistically significant difference between the subgroups of the two sexes, but both showed a smaller body size than normal Taiwanese children. When comparing the CPF within different BMI and FMI groups, the children in the excessive adiposity group had significantly lower values in metabolic equivalents (MET) at anaerobic threshold, peak MET, and measured peak oxygen consumption (VO₂) to predicted peak VO₂, regardless of sex. Moreover, boys (60.90%) presented poorer CPF than girls (74.22%, p < 0.001).

CONCLUSION

In Taiwan, patients with rTOF had poorer CPF than healthy peers. This study found that girls with rTOF had better CPF than boys with rTOF. The effect of gender stereotypes on sports participation and self-efficacy might be one of the contributing factors; however, further investigations are warranted to determine the causal effect.

Ventricular Myocardial Deformation in Fetuses With Tetralogy of Fallot: A Necessary Field of Investigation

Background: Tetralogy of Fallot (TOF) is one of the most common cyanotic congenital heart defects (CHDs). The patterns of fetal myocardial deformations in TOF have not been well-studied. This study aimed to assess biventricular myocardial deformations in fetuses with TOF compared with normal fetuses.

Methods: A retrospective cohort study of fetuses with TOF and gestational age (GA)-matched controls was conducted at a single tertiary referral center from 2014 to 2020. All enrolled fetuses underwent detailed echocardiography, and four-chamber video-clips were recorded and analyzed offline for deformation assessment by using two-dimensional speckle tracking echocardiography (2D-STE). Comparisons for baseline characteristics, cardiac morphological measurements (ventricular, atrial, and great arterial diameters or ratios, global sphericity index), systolic function parameters [ejection fraction (EF), fractional area change (FAC)], and strain parameters [global longitudinal strain (GLS), global longitudinal strain rate in systole and diastole (GLSRs, GLSRd)] were performed between fetuses with TOF and GA-matched controls.

Results: Fifty-two fetuses with TOF and 52 GA-matched controls were enrolled in this study. Fetuses with TOF exhibited similar left ventricular (LV) EF (58.51 ± 5.11% vs. 57.59 ± 5.38%, P = 0.16) and right ventricular (RV) FAC (43.64 ± 2.89% vs. 44.27 ± 3.04%, P = 0.25), compared to normal fetuses. While, in deformational analysis, TOF fetuses demonstrated significantly lower LV and RV GLS values (−22.57 ± 2.91% vs. −27.39 ± 4.38%, P < 0.001 for LV GLS; −24.27 ± 3.18% vs. −28.71 ± 4.48%, P < 0.001 for RV GLS). Both LV GLS (r = −0.518, P < 0.001) and RV GLS (r = −0.534, P < 0.001) were found negatively correlated with the aortic valve-to-pulmonary valve diameter ratio (AV:PV ratio). Z-scores of PV annulus and main pulmonary artery (MPA) also had positive correlation with LV and RV GLS, respectively.

Conclusions: Decreased biventricular myocardial deformations can appear even in fetuses with TOF with normal systolic ventricular function. Both LV and RV GLS values are correlated with the severity of right ventricular outflow tract obstruction. It indicates 2D-STE may be a more sensitive tool to assess fetal cardiac function than the conventional echocardiographic methods.

Tricuspid Valve Intervention at the Time of Pulmonary Valve Replacement in Adults With Congenital Heart Disease: A Systematic Review and Meta-Analysis

Background

Tricuspid regurgitation (TR) is a common finding in adults with congenital heart disease referred for pulmonary valve replacement (PVR). However, indications for combined valve surgery remain controversial. This study aimed to evaluate early results of concomitant tricuspid valve intervention (TVI) at the time of PVR.

Methods and Results

Observational studies comparing TVI+PVR and isolated PVR were identified by a systematic search of published research. Random‐effects meta‐analysis was performed, comparing outcomes between the 2 groups. Six studies involving 749 patients (TVI+PVR, 278 patients; PVR, 471 patients) met the eligibility criteria. In the pooled analysis, both TVI+PVR and PVR reduced TR grade, pulmonary regurgitation grade, right ventricular end‐diastolic volume, and right ventricular end‐systolic volumes. TVI+PVR, but not PVR, was associated with a decrease in tricuspid valve annulus size (mean difference, −6.43 mm, 95% CI, −10.59 to −2.27; P=0.010). Furthermore, TVI+PVR was associated with a larger reduction in TR grade compared with PVR (mean difference, −0.40; 95% CI, −0.75 to −0.05; P=0.031). No evidence could be established for an effect of either treatment on right ventricular ejection fraction or echocardiographic assessment of right ventricular dilatation and dysfunction. There was no evidence for a difference in hospital mortality or reoperation for TR.

Conclusions

While both strategies are effective in reducing TR and right ventricular volumes, routine TVI+PVR can reduce TR grade to a larger extent than isolated PVR. Further studies are needed to identify the subgroups of patients who might benefit most from combined valve surgery.

Whole-Exome Sequencing Reveals a Novel Mutation of FLNA Gene in an Iranian Family with Nonsyndromic Tetralogy of Fallot

OBJECTIVE

Tetralogy of Fallot (TOF) is one of the most common congenital abnormalities that need early intervention. Here, for the first time, we report a nonsyndromic form of TOF caused by a novel variant in the FLNA gene in 2 siblings of an Iranian family.

METHODS

The family underwent a complete workup, including karyotyping, sequencing of 6 common genes in congenital heart diseases (GATA4, NKX2-5, ZIC3, FOXH1, NODAL, and GJA1), array comparative genomic hybridization, multiplex ligation-dependent probe amplification, and whole-exome sequencing. Segregation and in silico analysis were also conducted for the identified variant.

RESULTS

A variant, c.3415C>T, in the FLNA gene was found in both affected brothers in this family; this variant was heterozygous in their mother. Bioinformatics tools predicted the variant as a pathogenic one.

CONCLUSION

Many allelic disorders have been reported for FLNA mutations. Mutations in this gene may cause a nonsyndromic congenital form of TOF.

Heart failure in adult congenital heart disease: tetralogy of Fallot

The number of rTOF patients who survive into adulthood is steadily rising, with currently more than 90% reaching the third decade of life. However, rTOF patients are not cured, but rather have a lifelong increased risk for cardiac and non-cardiac complications. Heart failure is recognized as a significant complication. Its occurrence is strongly associated with adverse outcome. Unfortunately, conventional concepts of heart failure may not be directly applicable in this patient group. This article presents a review of the current knowledge on HF in rTOF patients, including incidence and prevalence, the most common mechanisms of heart failure, i.e., valvular pathologies, shunt lesions, left atrial hypertension, primary left heart and right heart failure, arrhythmias, and coronary artery disease. In addition, we will review information regarding extracardiac complications, risk factors for the development of heart failure, clinical impact and prognosis, and assessment possibilities, particularly of the right ventricle, as well as management strategies. We explore potential future concepts that may stimulate further research into this field.

Pulmonary Vein Index Is Associated With Early Prognosis of Surgical Treatment for Tetralogy of Fallot

Objectives: To evaluate the predictive value of the pulmonary vein index (PVI) in the early prognosis of patients who received total tetralogy of Fallot (TOF) repair. Methods: We retrospectively reviewed 286 patients who underwent TOF repair in our institution between July 2013 and May 2020. The PVI, McGoon ratio, and Nakata index were measured and calculated. Logistic regression, linear stepwise regression, receiver operating characteristic (ROC) curve analysis, and Cox proportional hazards modeling were performed to evaluate the predictive value of PVI in the early prognosis after TOF repair surgery. Results: The median age and body weight were 1.23 (0.22-15.02) years and 9.00 (3.00-44.00) kg, respectively. There were five early deaths. The areas under the ROC curve for death were 0.89, 0.79, and 0.88 for the McGoon ratio, Nakata index, and PVI, respectively. A lower PVI better predicted prolonged postoperative hospital stay, cardiac intensive care unit stay, and ventilator time (Hazard Ratio, HR [95% Confidence intervals, CI]: 1.003 [1.002-1.004], p < 0.001; 1.002 [1.001-1.004], p < 0.001; 1.002 [1.001-1.003], p < 0.001, respectively) and was a significant risk factor for high 24 h max Vasoactive inotropic score (Crude Odds Ratio [OR] [95% CI]: -0.015 [-0.022, -0.007], p < 0.001), serous effusion (Crude OR [95% CI]: 0.996 [0.992-0.999], p = 0.020), delayed sternal closure (Crude OR [95% CI]: 0.983 [0.971-0.996], p = 0.010), and the need for peritoneal dialysis (Crude OR [95% CI]: 0.988 [0.980-0.996], p = 0.005). The area under the ROC curve of PVI for delayed postoperative recovery was 0.722 (p < 0.001), and the estimated cutoff point was 300.3 mm²/m². Conclusion: PVI is a good predictor of early prognosis for surgical treatment of TOF patients.

Outcome and Associated Findings in Individuals with Pre- and Postnatal Diagnosis of Tetralogy of Fallot (TOF) and Prediction of Early Postnatal Intervention

PURPOSE

 The aim of our retrospective evaluation was to compare the outcome of patients with prenatal and postnatal diagnosis of Tetralogy of Fallot (TOF) and to analyze prenatal echocardiographic parameters predicting intervention within 30 days postnatal.

MATERIALS AND METHODS

 We evaluated 142 patients in our pediatric heart center and prenatal diagnosis center and prenatal practice Praenatal plus in Cologne between 01/08-06/16.

RESULTS

 Within the prenatal diagnosis group, 6/74 fetuses (8.1 %) had TOF with pulmonary atresia (TOF-PA), and 6 (8.1 %) had absent pulmonary valve syndrome (TOF-APVS). 14 (18.9 %) had an abnormal karyotype including 9/14 (64.3 %) with microdeletion 22q11.2. 25 (33.8 %) had extracardiac malformation. 4 (5.4 %) had agenesis of ductus arteriosus (DA), 22 (29.7 %) had right aortic arch (RAA) and 9 (12.2 %) had major aortopulmonary collateral arteries (MAPCAs). Within the postnatal diagnosis group, no patient had TOF-PA, 4/68 (5.9 %) had TOF-APVS. 12 (17.6 %) had extracardiac malformations, 9 (13.2 %) had an abnormal karyotype including 2/9 with microdeletion 22q11.2. 10 (14.7 %) had RAA, 9 (13.2 %) had MAPCAs. There were no cases with agenesis of DA. Increasing z-score values of the left/right pulmonary artery (LPA/RPA) prenatally were associated with a lower probability for early postnatal intervention (RPA: p = 0.017; LPA: p = 0.013). Within the prenatal diagnosis group, 12 of 41 (29.3 %) live-born patients with follow-up and intention to treat needed early intervention versus 7 (10.3 %) in the postnatal diagnosis group (p = 0.02). Within the postnatal diagnosis group, there were no deaths, while 2 (4.9 %) post-intervention deaths occurred in the prenatal diagnosis group.

CONCLUSION

 There are no significant differences concerning post-intervention survival in the prenatal diagnosis group versus the postnatal diagnosis group. Complex cases may be underrepresented in the postnatal diagnosis group. Smaller RPA/LPA values prenatally seem to be associated with early postnatal intervention.

Outflow tract geometries are associated with adverse outcome indicators in repaired tetralogy of Fallot

OBJECTIVES

A wide variety of right ventricular outflow tract (RVOT) and pulmonary artery (PA) geometries has been reported in patients with repaired tetralogy of Fallot (rTOF). We aimed to investigate the associations between RVOT/PA geometries and outcome indicators in a large rTOF cohort receiving non-conduit repair.

METHODS

Three-dimensional magnetic resonance angiographic images of 206 patients with rTOF who had a pulmonary regurgitation (PR) fraction ≥20% were reviewed. Patients' RVOT geometry was quantitatively classified into 4 distinct shapes (tubular, hourglass, pyramid, and inverted trapezoid). Bilateral PA size discrepancy was defined as the diameter of the smaller side being less than 70% of that of the bigger side.

RESULTS

Based on lateral projection of the 3-dimensional images, patients with an inverted trapezoid-shaped RVOT had the smallest RV end-diastolic volume index (EDVi) (108.7 ± 24.3 mL/m²) and pulmonary valve annulus diameter, and shortest QRS duration, whereas those with a pyramid-shaped RVOT had the largest RV EDVi (161.0 ± 44.6 mL/m²) and pulmonary valve annulus diameter. Similar trends of differences were also observed if such classifications were based on the frontal projections. Multivariable analysis revealed that RVOT shapes, subvalvular diameter, PR fraction, QRS duration, and the presence of bilateral PA size discrepancy were independent determinants of RV EDVi. Furthermore, having bilateral PA size discrepancy (25.2%) was independently associated with lower peak oxygen consumption (P = .041).

CONCLUSIONS

Distinct RVOT morphologies and branch PA size discrepancy are associated with variations in RV remodeling and exercise capacity in patients with rTOF. These findings may aid decision-making regarding reintervention for PR and branch PA size discrepancy.

How pulmonary valve regurgitation after tetralogy of fallot repair changes the flow dynamics in the right ventricle: An in vitro study

Tetralogy of Fallot is the most common cyanotic congenital disease, affecting 10% of children with congenital heart disease. The surgical management of patients with Tetralogy of Fallot leads, however, to significant detrimental effects on the right ventricle including pulmonary valve regurgitation. This experiment aimed to simulate different cases of pulmonary valve regurgitation with varying degrees of severity in order to observe the changes in flow structures present in the right ventricle. Planar time-resolved particle image velocimetry measurements have been performed on a custom-made double activation simulator reproducing flow conditions in a model of a right ventricle. Changes in flow characteristics in the right ventricle have been evaluated in terms of velocity fields and profiles, tricuspid inflow jet orientation and viscous energy dissipation. Our results show that pulmonary valve regurgitation significantly alters the flow in the right ventricle mostly by impairing the diastolic inflow through the tricuspid valve and by increasing viscous energy loss. This fundamental work should allow for a better understanding of such changes in the RV flow dynamics. It may also help in developing new strategies allowing for a better follow-up of patients with repaired TOF and for decision-making in terms of pulmonary valve replacement.

Importance of pulmonary valve morphology for pulmonary valve preservation in tetralogy of Fallot surgery: comparison of the echocardiographic parameters

BACKGROUND

The decision to use transannular patching (TAP) during tetralogy of Fallot (TOF) repair depends on the pulmonary valve annulus size; the z score of the pulmonary annulus is the most commonly used predictor. However, definitive results are not obtained with z scores as different z score data sets are used for different parameters.

PURPOSE

This study aimed to identify the echocardiographic and other key factors that warranted a change in the surgical method during TOF surgery.

METHODS

Sixty-two patients were enrolled and divided into a pulmonary valve (PV) preservation group and a TAP group. Their medical records were reviewed.

RESULTS

The z score for PV annulus (PVA), ratio of the PVA to aortic annulus size, and ratio of PVA to descending aorta (DAO) size were significantly different between the PV preservation and TAP groups (-1.72±1.52 vs. -3.07±1.94, P=0.004; 0.62±0.12 vs. 0.50±0.14, P=0.002; and 1.32±0.32 vs. 1.07±0.36, P= 0.008, respectively). For TAP repair, the PVA z score had a sensitivity of 65.4% and specificity of 73.1%, ratio of PVA to aortic annulus size had a sensitivity of 73.1% and specificity of 65.4%, and ratio of PVA to DAO size had a sensitivity of 69.2% and specificity of 57.7%. The TAP group showed more monocuspid PVs (P=0.011), while the PV preservation group showed more tricuspid PVs (P=0.027). Commissurotomy was more frequently performed in the PV preservation group than in the TAP group (P=0.001). Of patients with commissurotomy, 58% showed a PV z score<-2.

CONCLUSION

Although various echocardiographic parameters may serve as predictors for determining surgical methods for TOF patients, the PV morphology and tissue characteristics should also be considered.

Generation of human iPSC line from a patient with Tetralogy of Fallot, YAHKMUi001-A, carrying a mutation in TBX1 gene

The human induced pluripotent stem cell (iPSC) line YAHKMUi001-A was derived from the dermal fibroblasts of a patient with Tetralogy of Fallot (TOF), with a mutation in the TBX1 gene (c.928G > A). The skin fibroblasts were obtained from a 4-year-old boy, and were infected with Sendai virus expressing the Yamanaka factors. The YAHKMUi001-A iPSC line expresses pluripotent stem cell markers, displays a normal karyotype, and has the capacity to differentiate into 3 germ layers. This cell line model can be a good tool to study the pathological mechanism of the TBX1 gene mutations associated with TOF.

Whole Exome Sequencing Reveals the Major Genetic Contributors to Nonsyndromic Tetralogy of Fallot

RATIONALE

Familial recurrence studies provide strong evidence for a genetic component to the predisposition to sporadic, nonsyndromic Tetralogy of Fallot (TOF), the most common cyanotic congenital heart disease phenotype. Rare genetic variants have been identified as important contributors to the risk of congenital heart disease, but relatively small numbers of TOF cases have been studied to date.

OBJECTIVE

We used whole exome sequencing to assess the prevalence of unique, deleterious variants in the largest cohort of nonsyndromic TOF patients reported to date.

METHODS AND RESULTS

Eight hundred twenty-nine TOF patients underwent whole exome sequencing. The presence of unique, deleterious variants was determined; defined by their absence in the Genome Aggregation Database and a scaled combined annotation-dependent depletion score of ≥20. The clustering of variants in 2 genes, NOTCH1 and FLT4, surpassed thresholds for genome-wide significance (assigned as P<5×10^-8) after correction for multiple comparisons. NOTCH1 was most frequently found to harbor unique, deleterious variants. Thirty-one changes were observed in 37 probands (4.5%; 95% CI, 3.2%-6.1%) and included 7 loss-of-function variants 22 missense variants and 2 in-frame indels. Sanger sequencing of the unaffected parents of 7 cases identified 5 de novo variants. Three NOTCH1 variants (p.G200R, p.C607Y, and p.N1875S) were subjected to functional evaluation, and 2 showed a reduction in Jagged1-induced NOTCH signaling. FLT4 variants were found in 2.4% (95% CI, 1.6%-3.8%) of TOF patients, with 21 patients harboring 22 unique, deleterious variants. The variants identified were distinct to those that cause the congenital lymphoedema syndrome Milroy disease. In addition to NOTCH1, FLT4 and the well-established TOF gene, TBX1, we identified potential association with variants in several other candidates, including RYR1, ZFPM1, CAMTA2, DLX6, and PCM1.

CONCLUSIONS

The NOTCH1 locus is the most frequent site of genetic variants predisposing to nonsyndromic TOF, followed by FLT4. Together, variants in these genes are found in almost 7% of TOF patients.

Functional Capacity Is Affected by Younger Age of Repair in Tetralogy of Fallot Patients But Not by Era of Repair

Background:

Cardiopulmonary exercise testing is widely used to assess functional capacity in patients with tetralogy of Fallot after surgical repair. Little is known regarding the impact of age at the time of primary complete repair and surgical era effect on exercise capacity.

Methods:

A retrospective, single-center chart review was done from 1976 to 2016 on pediatric patients with tetralogy of Fallot who underwent cardiopulmonary exercise testing with cycle ergometry utilizing the James protocol and were then sorted by repair before/after 1990 and by age of complete repair before/after one year. Exclusion criteria included submaximal tests, incomplete data, previous pulmonary valve replacement, and surgery prior to complete repair (ie, Blalock-Taussig shunt placement).

Results:

When comparing the groups who underwent primary complete repair before (N = 39) and after (N = 26) one year of age, the younger group demonstrated a higher percentage of predicted peak oxygen consumption ([Formula: see text] o2peak; 83.1% ± 11.8% vs 73.1% ± 16.1%; P = .005) despite having worse pulmonary insufficiency at the time of exercise testing. There were no differences in heart rate and blood pressure response. Age of repair was independently associated with [Formula: see text] o2peak. Data were statistically similar to the study eras (repair before 1990, N = 23; repair after 1990, N = 65): percentage of predicted [Formula: see text] o2peak (81.4% ± 13.6% vs 79.1% ± 14.4%, P = .5), maximal systolic blood pressure (155.1 ± 22.4 mm Hg vs 153.9 ± 17 mm Hg, P = .8), and percentage of predicted maximal heart rate (89.8% ± 9% vs 92% ± 7.1%, P = .3).

Conclusions:

Older age at primary repair appears to negatively impact [Formula: see text] o2peak; however, era effect does not appear to influence cardiopulmonary exercise testing outcomes.

Comparison of Image Acquisition Techniques in Four-Dimensional Flow Cardiovascular MR on 3 Tesla in Volunteers and Tetralogy of Fallot Patients

Four-dimensional phase-contrast (PC) velocity-encoded flow magnetic resonance imaging (4D flow MRI) is a potentially valuable tool for studying cardiovascular hemodynamics for disease monitoring and/or treatment planning. In this study we compared the performance of two 4D flow MRI pulse sequences - echo-planar imaging (EPI) and segmented gradient-echo (turbo-field-echo or TFE on vendor's platform) - on a clinical 3T system in 6 human subjects including 3 patients with Tetralogy of Fallot (TOF). For aortic flow rate, the coefficients of variation (COV) between 2D and 4D EPI were 7.0% and 7.7% for controls and patients respectively. The corresponding COV between 2D and 4D TFE were 19.0% and 18.3% for controls and patients respectively. The COV between 4D TFE and 4D EPI were larger than 18.7% in kinetic energy analysis. 4D EPI demonstrated acceptable accuracy of intra-cardiac flow quantification, which was also shown in the ex-vivo phantom measurements.

A Methodology to Assess Subregional Geometric Complexity for Tetralogy of Fallot Patients

During surgical repair of tetralogy of fallot (TOF), pulmonary valve preservation (preservative repair) has demonstrated improved long-term outcomes compared to repairs that incise into the valve annulus (nonpreservative repair). Given the influence of geometry on hemodynamics, the success of preservative repair may be linked to the suitability of the preoperative patient geometry. However, the specific patient anatomies that may be predisposed to successful preservative repair are unknown due to significant interpatient variability in right ventricular outflow tract (RVOT) and pulmonary artery geometries, as well as the limitations in current methods of subregional geometric analysis. As a first step toward understanding the link between geometry and hemodynamics in TOF patients at a subregion level, we characterize the TOF geometry from the right ventricular infundibulum (INF) to the left and right pulmonary arteries. Our process consists of segmentation of magnetic resonance (MR) images and analysis of cross-sectional slices of the geometries along the centerlines. For the INF, main, left, and right pulmonary arteries individually, we quantify geometric parameters important in determining hemodynamic characteristics such as flow separation and recirculation, which can influence the degree of regurgitation. Specifically, we calculate the diameter along the subregion length, the average diameter, length, and tortuosity for each segment, as well as the bifurcation, left pulmonary artery (LPA) and right pulmonary artery (RPA) branch angles. This approach enables direct geometric comparisons within and among patients and allows for observation of the range in anatomic presentation. We have applied this approach to a dataset of 11 postoperative TOF patients, repaired with both preservative and nonpreservative surgical techniques.

Clinical and postmortem findings of pentalogy of Fallot in an 18-month-old Holstein heifer

An 18-month-old female Holstein Friesian heifer presented with a history of stunted growth and a recent onset of anorexia; she presented with cyanosis and eventually died. A postmortem examination revealed obstruction of the right ventricular outflow tract, ventricular septal defect, overriding aortic root, right ventricular hypertrophy, and an atrial septal defect, indicating a pentalogy of Fallot (POF). In addition to POF, the heifer also had pulmonary artery dilatation, although she did not present with patent ductus arteriosus. This heifer had the longest lifespan among the Holstein cattle reported to have POF, which may be secondary to delayed pulmonary obstruction due to deformation of one of the pulmonary valves.

The Functional Polymorphism R129W in the BVES Gene Is Associated with Sporadic Tetralogy of Fallot in the Han Chinese Population

Background: Tetralogy of Fallot (TOF) accounts for ∼10% of congenital heart disease cases. The blood vessel epicardial substance (BVES) gene has been reported to play a role in the function of adult hearts. However, whether allelic variants in BVES contribute to the risk of TOF and its possible mechanism remains unknown. Methods: The open reading frame of the BVES gene was sequenced using samples from 146 TOF patients and 100 unrelated healthy controls. qRT-PCR and western blot assays were used to confirm the expression of mutated BVES variants in the TOF samples. The online software Polyphen2 and SIFT were used to predict the deleterious effects of the observed allelic variants. The effects of these allelic variants on the transcriptional activities of genes were examined using dual-fluorescence reporter assays. Results: We genotyped four single nucleotide polymorphisms (SNPs) in the BVES gene from each of the 146 TOF patients. Among them, the minor allelic frequencies of c.385C>T (p.R129W) were 0.035% in TOF, but ∼0.025% in 100 controls and the Chinese Millionome Database. This allelic variant was predicted to be a potentially harmful alteration by the Polyphen2 and SIFT softwares. qRT-PCR and western blot analyses indicated that the expression of BVES in the six right ventricular outflow tract samples with the c.385C>T allelic variant was significantly downregulated. A dual-fluorescence reporter system showed that the c.385C>T allelic variant significantly decreased the transcriptional activity of the BVES gene and also decreased transcription from the GATA4 and NKX2.5 promoters. Conclusions: c.385C>T (p.R129W) is a functional SNP of the BVES gene that reduces the transcriptional activity of BVES in vitro and in vivo in TOF tissues. This subsequently affects the transcriptional activities of GATA4 and NKX2.5 related to TOF. These findings suggest that c.385C>T may be associated with the risk of TOF in the Han Chinese population.

When is the Best Time for Corrective Surgery in Patients with Tetralogy of Fallot between 0 and 12 Months of Age?

Objective

To identify the best time for corrective surgery of tetralogy of Fallot (TF) in children aged 0-12 months and to report the most frequent complications during the first 3 years postoperatively.

Methods

Systematic review of studies published between 2000 and 2017 on corrective surgery for TF. Articles were selected through search of electronic databases (PubMed, SciELO, Scopus, Lilacs, Google Scholar, and Cochrane). Length of stay in intensive care unit, duration of mechanical ventilation, and peri/postoperative complications were analyzed for data discussion and research interpretation.

Conclusion

Definitive corrective surgery is the best alternative, and the earlier it is performed, the lower the occurrence of harmful effects and the greater the chances of cardiorespiratory recovery. This systematic review suggests that the best time to perform definitive corrective surgery for TF in the first year of life is during 3-6 months of age in children with no or mild symptoms. Children with severe symptoms should undergo surgery immediately.

Pulmonary effects on exercise testing in tetralogy of Fallot patients repaired with a transannular patch

BACKGROUND

A transannular patch is often used in the contemporary surgical repair of tetralogy of Fallot. This can lead to significant pulmonary insufficiency and increased right ventricular volumes and ultimately pulmonary valve replacement. Cardiopulmonary exercise testing is used to assess exercise capacity in tetralogy of Fallot patients before pulmonary valve replacement. There is only few published literatures on how lung function affects functional capacity in tetralogy of Fallot patients repaired with a transannular patch.

METHODS

A retrospective chart review was done from 2015 to 2017 on patients with tetralogy of Fallot who underwent maximal effort cardiopulmonary exercise testing with cycle ergometry and with concurrent pulmonary function testing. Tetralogy of Fallot patients repaired with a transannular patch without pulmonary valve replacement were compared with age, gender, and size-matched normal controls.

RESULTS

In the tetralogy of Fallot group, 24 out of 57 patients underwent primary repair with a transannular patch. When compared to the normal controls, they demonstrated abnormal predicted forced expiratory volume in one second (79 ± 23.1% versus 90.7 ± 14.1%, p&lt;0.05), predicted maximal voluntary ventilation (74 ± 18% versus 90.5 ± 16.2%, p&lt;0.05) while having low-normal predicted forced vital capacity (80.5 ± 17.2% versus 90.2 ± 12.4%, p&lt;0.05) and normal breathing reserve percentage (50.3 ± 11.3% versus 47.5 ± 17.3%, p = 0.52). Cardiopulmonary exercise testing abnormalities included significantly lower percent predicted oxygen consumption (63.2 ± 12.2% versus 87 ± 12.1%, p&lt;0.05), maximal heart rate (171.8 ± 18.9 versus 184.6 ± 13.6, p&lt;0.05), and percent predicted maximum workload (61.7 ± 15.9% versus 88.3 ± 21.5%, p&lt;0.05).

CONCLUSIONS

Tetralogy of Fallot patients repaired with a transannular patch can have abnormal pulmonary function testing with poor exercise capacity in addition to chronotropic incompetence and impaired muscular power.

Rare mutations of ADAM17 from TOFs induce hypertrophy in human embryonic stem cell-derived cardiomyocytes via HB-EGF signaling

Tetralogy of Fallot (TOF) is the most common cyanotic form of congenital heart defects (CHDs). The right ventricular hypertrophy is associated with the survival rate of patients with repaired TOF. However, very little is known concerning its genetic etiology. Based on mouse model studies, a disintergrin and metalloprotease 10/17 (ADAM10 and ADAM17) are the key enzymes for the NOTCH and ErbB pathways, which are critical pathways for heart development. Mutations in these two genes have not been previously reported in human TOF patients. In this study, we sequenced ADAM10 and ADAM17 in a Han Chinese CHD cohort comprised of 80 TOF patients, 286 other CHD patients, and 480 matched healthy controls. Three missense variants of ADAM17 were only identified in 80 TOF patients, two of which (Y42D and L659P) are novel and not found in the Exome Aggregation Consortium (ExAC) database. Point mutation knock-in (KI) and ADAM17 knock-out (KO) human embryonic stem cells (hESCs) were generated by CRISPR/Cas9 and programmed to differentiate into cardiomyocytes (CMs). Y42D or L659P KI cells or complete KO cells all developed hypertrophy with disorganized sarcomeres. RNA-seq results showed that phosphatidylinositide 3-kinases/protein kinase B (PI3K/Akt), which is downstream of epidermal growth factor receptor (EGFR) signaling, was affected in both ADAM17 KO and KI hESC-CMs. In vitro experiments showed that these two mutations are loss-of-function mutations in shedding heparin-binding EGF-like growth factor (HB-EGF) but not NOTCH signaling. Our results revealed that CM hypertrophy in TOF could be the result of mutations in ADAM17 which affects HB-EGF/ErbB signaling.

Survey of multinational surgical management practices in tetralogy of Fallot

BACKGROUND

A wide variety of surgical strategies are used in tetralogy of Fallot repair. We sought to describe the international contemporary practice patterns for surgical management of tetralogy of Fallot.

METHODS

Surgeons from 18 international paediatric cardiac surgery centres (representing over 1800 tetralogy of Fallot cases/year) completed a Research Electronic Data Capture-based survey. Participating countries include: China (4), India (2), Nepal (1), Korea (1), Indonesia (1), Saudi Arabia (3), Japan (1), Turkey (1), Australia (1), United States of America (2), and Canada (1). Summary measures were reported as means and counts (percentages). Responses were weighted based on case volume/centre.

RESULTS

Primary repair is the prevalent strategy (83%) with variation in age at elective repair (range). Approximately 47% of sites use patient age as a factor in determining the strategy, with age 90% of all trans-annular repairs.

CONCLUSIONS

In this cohort representing 11 countries, there is variation in tetralogy of Fallot surgical management with no consensus on standard of practice. A large international prospective cohort study would allow analysis of impact of underlying anatomy and repair strategy on early and late outcomes.

The change of QRS duration after pulmonary valve replacement in patients with repaired tetralogy of Fallot and pulmonary regurgitation

Purpose

This study aimed to analyze changes in QRS duration and cardiothoracic ratio (CTR) following pulmonary valve replacement (PVR) in patients with tetralogy of Fallot (TOF).

Methods

Children and adolescents who had previously undergone total repair for TOF (n=67; median age, 16 years) who required elective PVR for pulmonary regurgitation and/or right ventricular out tract obstruction were included in this study. The QRS duration and CTR were measured pre- and postoperatively and postoperative changes were evaluated.

Results

Following PVR, the CTR significantly decreased (pre-PVR 57.2%±6.2%, post-PVR 53.8%±5.5%, P=0.002). The postoperative QRS duration showed a tendency to decrease (pre-PVR 162.7±26.4 msec, post-PVR 156.4±24.4 msec, P=0.124). QRS duration was greater than 180 msec in 6 patients prior to PVR. Of these, 5 patients showed a decrease in QRS duration following PVR; QRS duration was less than 180 msec in 2 patients, and QRS duration remained greater than 180 msec in 3 patients, including 2 patients with diffuse postoperative right ventricular outflow tract hypokinesis. Six patients had coexisting arrhythmias before PVR; 2 patients, atrial tachycardia; 3 patients, premature ventricular contraction; and 1 patient, premature atrial contraction. None of the patients presented with arrhythmia following PVR.

Conclusion

The CTR and QRS duration reduced following PVR. However, QRS duration may not decrease below 180 msec after PVR, particularly in patients with right ventricular outflow tract hypokinesis. The CTR and ECG may provide additional clinical information on changes in right ventricular volume and/or pressure in these patients.

Perioperative Factors Influence the Long-Term Outcomes of Children and Adolescents with Repaired Tetralogy of Fallot

Tetralogy of Fallot (TOF) often carries long-term seqüelae following surgical intervention. We hypothesized that early perioperative factors are associated with long-term adverse right ventricular (RV) remodeling, diminished exercise capacity, and increased morbidity. We conducted a retrospective cohort study of patients operated for TOF that underwent cardiac magnetic resonance imaging study (CMR), exercise stress test (EST), and detailed review of past medical history. Outcome variables included measures of RV size, and function, maximal work rate, and oxygen consumption, and interim hospitalizations, surgeries, and catheterizations. Thirty-nine subjects were included. Age at surgical repair was 0.3 ± 0.3 years and age at testing was 9.7 ± 1.4 years. On CMR, there was borderline RV dilation with moderate pulmonary insufficiency (PI) [RF 32% (8; 43)] and normal RV ejection fraction [60% (55; 67)]. On EST, there was low percent-predicted maximal oxygen consumption (77 ± 20%), and percent-predicted maximal work rate (84 ± 23%). On multivariable analysis, mechanical ventilation and Blalock-Taussig (BT) shunt prior to complete surgical repair were associated with the number of future hospitalizations. Duration of cardiopulmonary bypass and prior BT shunt were associated with future catheterizations. Prior BT shunt was a predictor of worse RVEF, while duration of mechanical ventilation and use of transannular patch were predictors of worse PI. Longer duration of mechanical ventilation (or LOS) was associated with worse maximal work rate. Surgical and perioperative factors may portend long-term RV remodeling and outcome in TOF. Further studies are warranted to explore these associations and potential underlying mechanisms.

Investigation of associated factors with post-operative outcomes in patients undergoing Tetralogy of Fallot correction

Background

Tetralogy of Fallot (TOF) is one of the congenital cardiac abnormality which occurs during embryonic time. Although surgical correction, especially early operation, is the best way to treat patients, still contributing factors in morbidity and mortality is controversial. The objective of this study is to investigate potential factors which might be correlated with post-operative outcomes of TOF.

Methods

In this retrospective study, 349 monitored patients with TOF correction were selected. Median of age was 4 (0.66–8) year, 58% of patients were male and 42% were female. Time of inotropic drug, extubation time, and ICU stay were considered as post-operative outcomes which extension of each of them increased the risk of death.

Results

Ventricular septal defect enlargement was associated with longer extubation time and ICU stay. Higher ratio of pre-operative haematocrit was correlated with mortality (0.047).

Conclusions

Results of this study demonstrated that haematocrit ratio before operation should be considered as a predictive factor, and patients with higher ratio of haematocrit require more care after operation. VSD enlargement is associated with longer extubation time and ICU stay.

[A prenatal ultrasound study of cerebral sulci and gyrus development in fetuses with tetralogy of Fallot]

OBJECTIVE

To evaluate the development of the cerebral sulci and gyrus and cerebral blood flow in fetuses with tetralogy of Fallot (ToF) in the second and third trimesters using ultrasound imaging.

METHODS

Forty fetuses (23-33⁺⁶ weeks) with ToF diagnosed using ultrasound imaging between December, 2015 and September, 2016 were analyzed in this study. The development of the cerebral sulci and gyrus was evaluated by measuring the parietal-occipital fissure (POF) depth, POF angle, sylvian fissure (SF) depth, SF width, uncovered insular width, calcarine fissure (CF) depth, hemisphere depth on the views of POF, SF and CF, uncovered insular ratio, biparietal diameter (BPD), and head circumference (HC). Cerebral hemodynamics were assessed by measuring the umbilical artery resistance index, umbilical artery pulsation index, middle cerebral artery pulsation index (MCA-PI), middle cerebral artery resistance index, the cerebral-to-placental resistance ratio, and the cerebroplacental ratio.

RESULTS

In ToF fetuses, the POF depth, SF depth, CF depth, BPD, HC and hemisphere depth on the views of parietal-occipital sulcus and calcarine sulcus were significantly smaller than those in the control group (P<0.05). The middle cerebral artery resistance index, middle cerebral artery pulsation index, the cerebral-to-placental resistance ratio and the cerebroplacental ratio were also significantly lower in ToF fetuses than in the control group (P<0.05).

CONCLUSION

The cerebral sulci and gyrus in ToF fetuses in second and third trimesters show underdevelopment compared with those in normal fetuses, and the changes in hemodynamics caused by abnormal cardiac structure might be one of the reasons for cerebral sulci and gyrus underdevelopment in fetuses with ToF.

The utility of preoperative level of erythrocytosis in the prediction of postoperative blood loss and 30-day mortality in patients with tetralogy of fallot

BACKGROUND

Postoperative major bleeding is a relatively common complication of patients undergoing corrective surgery of tetralogy of Fallot (TOF). Life-threatening blood losses can lead to aggressive transfusions or reoperation. Little is known about the risk factors associated with a bleeding tendency in TOF patients. This study aimed to establish predictive models for postoperative blood loss and mortality in TOF patients.

METHODS

We conducted a retrospective observational study involving patients with TOF who were posted for corrective cardiac surgery in a single hospital between 2010 and 2015. Hospital records including sociodemographic, pre- and intra-operative characteristics were extracted. Postoperative blood loss (within 24 and 48 h) and 30-day mortality were the primary and secondary outcomes, respectively. Multivariate linear and logistic regression models were used to identify determinants of outcomes.

RESULTS

A total of 60 patients were included in this study. The median age was 1 year (interquartile range = 0.62-5) and the male to female ratio of 1.7:1. Mean postoperative blood loss within 24 h was 283 ± 212 mL. In multivariate linear regression, preoperative hematocrit (β = 6.63, P = 0.042) and duration of intraoperative oxygenator with CPB (β = 5.16, P = 0.025) were significantly correlated with postoperative blood loss within 24 h. After adjusting for sociodemographic, intra- and post-operative characteristics, preoperative hematocrit (odds ratio [OR] = 1.10, 95% confidence interval [CI] = 1.01-1.21), and postoperative red blood cell transfusions (OR = 3.88, 95% CI = 1.16-12.9) showed statistically significant association with 30-day mortality. The area under the receiver operating characteristic curve of the multivariable model was 0.863.

CONCLUSIONS

Preoperative levels of erythrocytosis appear to predict postoperative blood loss and short-term mortality in TOF patients undergoing corrective surgery.

HAND1 Loss-of-Function Mutation Causes Tetralogy of Fallot

As the most prevalent form of birth defect in humans worldwide, congenital heart disease (CHD) is responsible for substantial morbidity and is still the leading cause of birth defect-related demises. Increasing evidence demonstrates that genetic defects play an important role in the pathogenesis of CHD, and mutations in multiple genes, especially in those coding for cardiac core transcription factors, have been causally linked to various CHDs. Nevertheless, CHD is a genetically heterogeneous disease and the genetic determinants underpinning CHD in an overwhelming majority of patients remain elusive. In the current study, genomic DNA was extracted from venous blood samples of 165 unrelated patients with CHD, and the coding exons and splicing junction sites of the HAND1 gene, which encodes a basic helix-loop-helix transcription factor essential for cardiovascular development, were sequenced. As a result, a novel heterozygous mutation, p.R118C, was identified in a patient with tetralogy of Fallot (TOF). The missense mutation, which was absent in 600 referential chromosomes, altered the amino acid that was completely conserved evolutionarily. Biological assays with a dual-luciferase reporter assay system revealed that the R118C-mutant HAND1 protein had significantly reduced transcriptional activity when compared with its wild-type counterpart. Furthermore, the mutation significantly decreased the synergistic activation of a downstream target gene between HAND1 and GATA4, another cardiac core transcription factor associated with TOF. To our knowledge, this is the first report on the association of a HAND1 loss-of-function mutation with enhanced susceptibility to TOF in humans. The findings provide novel insight into the molecular etiology underlying TOF, suggesting potential implications for the improved prophylactic and therapeutic strategies for TOF.