Whole genome sequencing in transposition of the great arteries and associations with clinically relevant heart, brain and laterality genes.

BACKGROUND: The most common cyanotic congenital heart disease (CHD) requiring management as a neonate is transposition of great arteries (TGA). Clinically, up to 50% of TGA patients develop some form of neurodevelopmental disability (NDD), thought to have a significant genetic component. A "ciliopathy" and links with laterality disorders have been proposed. This first report of whole genome sequencing in TGA, sought to identify clinically relevant variants contributing to heart, brain and laterality defects. METHODS: Initial whole genome sequencing analyses on 100 TGA patients focussed on established disease genes related to CHD (n = 107), NDD (n = 659) and heterotaxy (n = 74). Single variant as well as copy number variant analyses were conducted. Variant pathogenicity was assessed using the American College of Medical Genetics and Genomics-Association for Molecular Pathology guidelines. RESULTS: Fifty-five putatively damaging variants were identified in established disease genes associated with CHD, NDD and heterotaxy; however, no clinically relevant variants could be attributed to disease. Notably, case-control analyses identified significantly more predicted-damaging, silent and total variants in TGA cases than healthy controls in established CHD genes (P < .001), NDD genes (P < .001) as well as across the three gene panels (P < .001). CONCLUSION: We present compelling evidence that the majority of TGA is not caused by monogenic rare variants and is most likely oligogenic and/or polygenic in nature, highlighting the complex genetic architecture and multifactorial influences on this CHD sub-type and its long-term sequelae. Assessment of variant burden in key heart, brain and/or laterality genes may be required to unravel the genetic contributions to TGA and related disabilities.

Periconceptional use of cod liver oil, a vitamin D source, could decrease the risk of CHD in offspring.

OBJECTIVE: To explore if there is association between vitamin D supplementation through cod liver oil ingestion around the periconceptional period and the risk of developing severe CHD in offspring. Furthermore, we would examine the interaction between vitamin D and folic acid supplementation in the association. METHODS: A case-control study was conducted in Shanghai Children's Medical Center, in which, a total of 262 severe CHD cases versus 262 controls were recruited through June 2016 to December 2017. All children were younger than 2 years. To reduce potential selection bias and to minimise confounding effects, propensity score matching was applied. RESULTS: After propensity score matching, vitamin D supplementation seemed to be associated with decreased odds ratio of severe CHD (odds ratio = 0.666; 95% confidence intervals: 0.449-0.990) in the multivariable conditional logistic analysis. Furthermore, we found an additive interaction between vitamin D and folic acid supplementation (relative excess risk due to interaction = 0.810, 95% confidence intervals: 0.386-1.235) in the association. CONCLUSION: The results suggested that maternal vitamin D supplementation could decrease the risk of offspring severe CHD; moreover, it could strengthen the protective effect of folic acid. The significance of this study lies in providing epidemiological evidence that vitamin D supplementation around the periconceptional period could be a potential nutritional intervention strategy to meet the challenge of increasing CHD.

Hypoxia-induced ARHGAP26 deficiency inhibits the proliferation and migration of human ductus arteriosus smooth muscle cell through activating RhoA-ROCK-PTEN pathway.

The Rho family plays crucial roles in O2 -induced vasoconstriction, cell proliferation, and migration. Rho GTPase-activating protein 26 (ARHGAP26) is a GTPase-activating protein for the small GTPases of the Rho family. Our previous studies have demonstrated that ARHGAP26 expression was significantly downregulated in patent human ductus arteriosus (DA) tissue. However, its role underlying the maintenance of DA patency is unclear. In this study, patent (fetal) and constricted (newborn) mouse DA tissues were harvested to confirm the differences in the levels of expression of ARHGAP26. Human DA smooth muscle cells (DASMCs) were isolated and cultured in vitro and used to test the function of ARHGAP26. The expression of ARHGAP26 was significantly lower in patent (fetal) than constricted (newborn) mouse DA. ARHGAP26-knocked-down human DASMCs showed reduced proliferation and migration, which are both crucial to anatomic closure of DA. Moreover, after culturing under hypoxic conditions, the expression of ARHGAP26 in human DASMCs was significantly lower and hypoxia-induced ARHGAP26 deficiency activated the phosphorylation level of phosphatase and tensin homolog (PTEN) in DASMCs by mediating the activity of RhoA and RhoA-associated kinase 1 (ROCK1). Use of Y27632, an inhibitor of ROCK which further reduces the phospholipid activity of PTEN can reverse the inhibitory effect of PTEN on the proliferation and migration of human DASMCs. This provides insight into the molecular regulation of the RhoA-ROCK-PTEN pathway in DA smooth muscle cells, which may be a suitable therapeutic target or diagnostic biomarker for perinatal DA tone management.

Associations between maternal social support and stressful life event with ventricular septal defect in offspring: a case-control study.

BACKGROUND: Previous studies suggested that maternal subjective feeling of stress seemed to be involved in the incidence of congenial heart disease in offspring. To better understand the findings, our study would discuss the relationships of maternal exposure to stressful life event and social support, which are more objective and comprehensive indicators of stress, around periconceptional period with the risk of ventricular septal defect (VSD), the most popular subtype of congenital heart disease. METHODS: A hospital-based case-control study was conducted through June, 2016 to December, 2017. We collected maternal self-reports of 8 social support questions in 3 aspects and 8 stressful life events among mothers of 202 VSD cases and 262 controls. Social support was categorized into low, medium high, and high (higher is better), and stressful life event was indexed into low, medium low, and high (higher is worse). Logistic regression models were applied to estimate adjusted odds ratios and 95% confidence intervals (95% CI). RESULTS: The adjusted odds ratio of high stressful life event was 2.342 (95% CI: 1.348, 4.819) compared with low stressful life event. After crossover analysis, compared with low event & high support, the adjusted odds ratio of low event & low support, high event & high support, and high event & low support were 2.059 (95% CI: 1.104, 3.841), 2.699 (95% CI: 1.042, 6.988) and 2.781 (95% CI: 1.033, 7.489), respectively. CONCLUSIONS: In summary, we observed an increased risk of VSD when pregnant women exposed to stressful life events, however, social support could, to some extent, reduce the risk of stressful life event.

Total Anomalous Pulmonary Venous Connection: The Current Management Strategies in a Pediatric Cohort of 768 Patients.

BACKGROUND: Total anomalous pulmonary venous connection (TAPVC) is a rare form of congenital heart disease. This study describes current surgical treatment strategies and experiences in a cohort of patients from 2 congenital cardiac centers in Shanghai and Guangdong in China. METHODS: This retrospective study included 768 patients operated on between 2005 and 2014. Although most patients (n=690) underwent conventional repair, a sutureless technique was used in 10% (n=78) of cases. A multilevel mixed-effects parametric survival model and a competing-risk analysis were used to analyze associated risk factors for death and recurrent pulmonary venous obstruction (PVO), respectively. Kaplan-Meier analysis was used to analyze the overall survival. The Nelson-Aalen cumulative risk curve was used to compare distributions of time with recurrent PVO. RESULTS: The mean surgical age and weight were 214.9±39.2 days and 5.4±3.6 kg, respectively. Obstructed TAPVC (PVO) was documented in 192 (25%) of the 768 patients. There were 38 intraoperative deaths and 13 late deaths. A younger age at the time of repair (P=0.001), mixed (P=0.004) and infracardiac (P=0.035) TAPVC, preoperative PVO (P=0.027), prolonged cardiopulmonary bypass time (P<0.001), and longer duration of ventilation (P=0.028) were associated with mortality. The median follow-up was 23.2 months (range; 1-112 months). Among the 717 survivors, recurrent PVO was observed in 111 patients (15%). Associated risk factors for recurrent PVO included preoperative PVO (P<0.001), infracardiac TAPVC (P<0.001), mixed TAPVC (P=0.013), and prolonged cardiopulmonary bypass time (P<0.001). Sutureless technique was associated with a lower restenosis rate compared with conventional repair in patients with preoperative PVO (P=0.038), except in newborn patients (P=0.443). Reintervention for restenosis was performed in 24 patients. The function of most survivors (91%) was classified according to the New York Heart Association as functional class I or II. CONCLUSIONS: Surgical correction in patients with TAPVC with a biventricular anatomy can achieve an acceptable outcome. Risk factors such as a younger age at the time of repair, infracardiac and mixed TAPVC, and preoperative PVO were associated with a poorer prognosis.

GSK-3ß Inhibitor CHIR-99021 Promotes Proliferation Through Upregulating ß-Catenin in Neonatal Atrial Human Cardiomyocytes.

BACKGROUND: The renewal capacity of neonate human cardiomyocytes provides an opportunity to manipulate endogenous cardiogenic mechanisms for supplementing the loss of cardiomyocytes caused by myocardial infarction or other cardiac diseases. GSK-3ß inhibitors have been recently shown to promote cardiomyocyte proliferation in rats and mice, thus may be ideal candidates for inducing human cardiomyocyte proliferation. METHODS: Human cardiomyocytes were isolated from right atrial specimens obtained during routine surgery for ventricle septal defect and cultured with either GSK-3ß inhibitor (CHIR-99021) or ß-catenin inhibitor (IWR-1). Immunocytochemistry was performed to visualize 5-ethynyl-2'-deoxyuridine (EdU)-positive or Ki67-positive cardiomyocytes, indicative of proliferative cardiomyocytes. RESULTS: GSK-3ß inhibitor significantly increased ß-catenin accumulation in cell nucleus, whereas ß-catenin inhibitor significantly reduced ß-catenin accumulation in cell plasma. In parallel, GSK-3ß inhibitor increased EdU-positive and Ki67-positive cardiomyocytes, whereas ß-catenin inhibitor decreased EdU-positive and Ki67-positive cardiomyocytes. CONCLUSIONS: These results indicate that GSK-3ß inhibitor can promote human atrial cardiomyocyte proliferation. Although it remains to be determined whether the observations in atrial myocytes could be directly applicable to ventricular myocytes, the current findings imply that Wnt/ß-catenin pathway may be a valuable pathway for manipulating endogenous human heart regeneration.

Positional Relationship Between the Pulmonary Venous Confluence-Vertical Vein and Atria in Infracardiac Total Anomalous Pulmonary Venous Connection.

To explore the positional relationship between the pulmonary venous confluence-venous vein (PVC-VV) and both the atria in infracardiac total anomalous pulmonary venous connection (iTAPVC), using two-dimensional (2D) computerized tomography (CT) reconstruction. Through the 2D reconstruction of enhanced cardiac CT images of patients with iTAPVC, the projection of PVC-VV on coronal axial images was acquired and its location on the bilateral atrial splice was analyzed. Sagittal axial reconstruction was used to identify which atrium had a precise anterior-posterior positional relationship with PVC-VV. The type of iTAPVC, where the projection of PVC-VV was lying on the left atrium, and the left atrium had a precise anterior-posterior positional relationship with PVC-VV, was classified as the left atrial type. If the projection of PVC-VV was lying on the right atrium and the right atrium had a precise anterior-posterior positional relationship with PVC-VV, it was classified as the right atrial type. Finally, if the projection of PVC-VV was lying in the middle of the bilateral atria, and both the atria had precise anterior-posterior positional relationship with PVC-VV, it was referred to as the bilateral atrial type. Upon analysis of the 22 enhanced cardiac CT images, 6 were the left atrial type (27.27 %), 9 were right atrial type (40.91 %), while 7 were of the bilateral atrial type (31.82 %). The positional relationship between PVC-VV and the bilateral atria are variable, and iTAPVC classification using 2D CT reconstruction is an invaluable tool in designing the surgical approaches in iTAPVC.

Isobaric Tags for Relative and Absolute Quantitation-Based Proteomic Analysis of Patent and Constricted Ductus Arteriosus Tissues Confirms the Systemic Regulation of Ductus Arteriosus Closure.

We aimed to evaluate global changes in protein expression associated with patency by undertaking proteomic analysis of human constricted and patent ductus arteriosus (DA). Ten constricted and 10 patent human DAs were excised from infants with ductal-dependent heart disease during surgery. Using isobaric tags for relative and absolute quantitation-based quantitative proteomics, 132 differentially expressed proteins were identified. Of 132 proteins, voltage-gated sodium channel 1.3 (SCN3A), myosin 1d (Myo1d), Rho GTPase activating protein 26 (ARHGAP26), and retinitis pigmentosa 1 (RP1) were selected for validation by Western blot and quantitative real-time polymerase chain reaction analyses. Significant upregulation of SCN3A, Myo1d, and RP1 messenger RNA, and protein levels was observed in the patent DA group (all P ≤ 0.048). ARHGAP26 messenger RNA and protein levels were decreased in patent DA tissue (both P ≤ 0.018). Immunohistochemistry analysis revealed that Myo1d, ARHGAP26, and RP1 were specifically expressed in the subendothelial region of constricted DAs; however, diffuse expression of these proteins was noted in the patent group. Proteomic analysis revealed global changes in the expression of proteins that regulate oxygen sensing, ion channels, smooth muscle cell migration, nervous system, immune system, and metabolism, suggesting a basis for the systemic regulation of DA patency by diverse signaling pathways, which will be confirmed in further studies.

Elevated NCX1 and NCKX4 expression in the patent postnatal ductus arteriosus of ductal-dependent congenital heart disease patients.

Patency of the ductus arteriosus (DA) after birth is essential in ductal-dependent congenital heart disease. The Na(+)/Ca(2+) exchanger (NCX) has been demonstrated to play a key role in regulating vascular tone. The potassium-dependent Na(+)/Ca(2+) exchanger (NCKX) is a related family of NCX depending on the K(+) gradients which triggers DA constriction. The present study investigated the comparative expression of NCX and NCKX between a constricted DA and patent DA in human ductal-dependant congenital heart disease. Human DAs, which were patent (n = 10, age = 20.2 ± 4.3 days) or constricted (n = 10, age = 18.3 ± 3.9 days), were excised during surgery from neonates with ductal-dependent congenital heart disease. Western blotting analysis, real-time quantitative polymerase chain reaction analysis and immunofluorescence studies were performed to detect the protein and mRNA levels of NCX1, NCKX3, and NCKX4. The expressions of NCX1 and NCKX4 were significantly higher in the patent DA group at both the protein and mRNA levels, and expression was localized to the smooth muscle layer. These findings indicate that NCX1 and NCKX4 are up-regulated in human postnatal patent DAs and may represent potential therapeutic targets for maintaining DA patency in ductal-dependent congenital heart disease.

Hypoxia-induced cytosolic calcium influx is mediated primarily by the reverse mode of Na+/Ca2+ exchanger in smooth muscle cells of fetal small pulmonary arteries.

AIM: Constriction of small pulmonary arteries and high resistance of pulmonary circulation are important for maintaining fetal circulation before birth. In this study, we investigated how cytosolic free calcium concentration ([Ca(2+)]i) in fetal lamb small pulmonary artery smooth muscle cells (SPASMC) was affected by hypoxia and regulated by calcium pumps during this process. METHODS: (Ca(2+))i in response to acute hypoxia was determined spectrofluorometrically with fluo-3AM in cultured fetal SPASMC. Chemicals or solutions, including ryanodine, 2-aminoethoxydiphenyl borate, Ca(2+)-free solution with 20 mmol ethyleneglycoltetraacetic (EGTA), nimodipine, Na(+)-free medium and KB-R7943, were administrated at the same time point when samples were exposed to acute hypoxia. RESULTS: (Ca(2+))i in fetal lamb SPASMC increased under acute hypoxia. 2-Aminoethoxydiphenyl borate, an inhibitor of inositol triphosphate calcium store, partially attenuated the (Ca(2+))i increase after 6-min treatment. Ryanodine, an inhibitor of ryanodine-sensitive calcium stores, had no effect on the (Ca(2+))i increase. Ca(2+)-free solution with EGTA completely abolished this increase. Both nimodipine, that blocks the voltage-gated calcium channel, and KB-R7943, that inhibits the reverse mode of Na(+)/Ca(2+) exchanger, greatly diminished the hypoxia-induced (Ca(2+))i increase. The inhibitory effect of KB-R7943 was stronger than nimodipine, evidenced by the fact that (Ca(2+))i dropped near to the baseline level in the presence of KB-R7943 at a later time point. Low extracellular Na(+) concentration enhanced the hypoxia-induced increase of (Ca(2+))i. CONCLUSION: These results suggest that hypoxia-induced Ca(2+) increase in fetal SPASMC results from cytosolic Ca(2+) influx mediated primarily by the reverse mode of Na(+)/Ca(2+) exchanger.

Phthalate exposure and blood pressure in U.S. children aged 8-17 years (NHANES 2013-2018).

BACKGROUND: Current evidence from epidemiologic studies suggested that phthalate metabolites might be associated with blood pressure (BP) changes. However, the special relationship between phthalate metabolites and BP changes in children has not been clearly elucidated in existing researches. OBJECTIVES: We investigated the links between phthalate metabolites and various BP parameters, including systolic/diastolic BP, mean arterial pressure (MAP), and the presence of hypertension. METHODS: The population sample consisted of 1036 children aged 8 to 17 years from the 2013-2018 NHANES in the United States. High performance liquid chromatography-electrospray ionization-tandem mass spectrometry was used to measure urinary concentrations of 19 phthalate metabolites. Systolic/diastolic BP were derived from the average of three valid measurements, and MAP was calculated as (systolic BP + 2 × diastolic BP)/3. Hypertension was defined as mean systolic BP and/or diastolic BP that was ≥ 95th percentile for gender, age, and height reference. Linear regression, logistic regression, and weighted quantile sum (WQS) regression models were employed to assess the associations between phthalate exposure and systolic/diastolic BP, MAP, and hypertension. RESULTS: Ten of 19 phthalate metabolites including MCNP, MCOP, MECPP, MBP, MCPP, MEP, MEHHP, MiBP, MEOHP, and MBzP had detection frequencies > 85% with samples more than 1000. MCNP, MCOP, MECPP, MBP, MCPP, MEHHP, MiBP, MEOHP, and MBzP were generally negatively associated with systolic/diastolic BP and MAP, but not protective factors for hypertension. These associations were not modified by age (8-12 and 13-17 years) or sex (boys and girls). The above-mentioned associations were further confirmed by the application of the WQS analysis, and MCOP was identified as the chemical with the highest weight. CONCLUSION: Phthalate metabolites were associated with modest reductions in systolic/diastolic BP, and MAP in children, while appeared not protective factors for hypertension. Given the inconsistent results among existing studies, our findings should be confirmed by other cohort studies.

Understanding the Molecular Mechanisms of H2's Regulatory Effect on miR-29s for Brain Protection during Deep Hypothermic Circulatory Arrest.

INTRODUCTION: Research regarding post-operative brain protection after deep hypothermic circulatory arrest (DHCA) has gained attracted significant attention. We previously demonstrated that hydrogen can significantly reverse DHCA-induced brain damage. METHOD: In the current research, we have established the DHCA model successfully using a modified four-vessel occlusion method and injected miR-29s compounds into the hippocampal tissue of rats. RESULT: We were surprised to find hydrogen increased miR-29s expression in the hippocampal tissue of a DHCA rat model. The administration of agomiR-29s counteracted DHCA-induced hippocampal tissue injury, while the antamiR-29s had the opposite effects. CONCLUSION: Based on the above facts, the brain protection mechanism of hydrogen in DHCAtreated rats may be related to the upregulation of miR-29s, which can exert its beneficial effects by alleviating apoptosis, inflammation, and oxidation.

A surgical mouse model of neonatal right ventricular outflow tract obstruction by pulmonary artery banding.

BACKGROUD: Diseased animal models play an extremely important role in preclinical research. Lacking the corresponding animal models, many basic research studies cannot be carried out, and the conclusions obtained are incomplete or even incorrect. Right ventricular (RV) outflow tract (RVOT) obstruction leads to RV pressure overload (PO) and reduced pulmonary blood flow (RPF), which are 2 of the most important pathophysiological characteristics in pediatric cardiovascular diseases and seriously affect the survival rate and long-term quality of life of many children. Due to the lack of a neonatal mouse model for RVOT obstruction, it is largely unknown how RV PO and RPF regulate postnatal RV and pulmonary development. The aim of this study was to construct a neonatal RVOT obstruction mouse model. METHODS AND RESULTS: Here, we first introduced a neonatal mouse model of RVOT obstruction by pulmonary artery banding (PAB) on postnatal day 1. PAB induced neonatal RVOT obstruction, RV PO, and RPF. Neonatal RV PO induced cardiomyocyte proliferation, and neonatal RPF induced pulmonary dysplasia, the 2 features that are not observed in adult RVOT obstruction. As a result, PAB neonates exhibited overall developmental dysplasia, a sign similar to that of children with RVOT obstruction. CONCLUSIONS: Because many pediatric cardiovascular diseases are associated with RV PO and RPF, the introduction of a neonatal mouse model of RVOT obstruction may greatly enhance our understanding of these diseases and eventually improve or save the lives of many children.

Continuous cerebral and myocardial perfusion during one-stage repair for aortic coarctation with ventricular septal defect.

Controversy still exists concerning the use of deep hypothermic circulatory arrest (DHCA) and selective antegrade cerebral perfusion (SACP) for repair of aortic coarctation (CoA) with ventricular septal defect (VSD). This report therefore describes outcomes of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia compared with DHCA and SACP. Retrospective analysis was performed for 110 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Patients repaired under CCMP with mild hypothermia (32 °C) (group A, n = 60) were compared with those repaired under DHCA (18 °C) and SACP (group B, n = 50). In group A, the single arterial cannula perfusion technique was used for 15 patients (25 %), and the dual arterial cannula perfusion technique was used for 45 patients (75 %). The preoperative data were similar in the two groups. Group A had no hospital mortalities, compared with two mortalities (4 %) in group B. Group A had shorter myocardial ischemic and cardiopulmonary times, fewer delayed sternal closures, a shorter time to extubation, lower postoperative lactate levels, and fewer patients with low cardiac output requiring extracorporeal membrane oxygenation or with multiorgan failure than group B. During the postoperative course, no clinical or electrical neurologic events occurred in either group. The mean follow-up period was 5.2 ± 3.2 years for group A and 7.5 ± 3.1 years for group B (P = 0.048). One late death occurred in group B and no late deaths in group A. The actuarial survival for the two groups was similar (100 % for group A vs 96 % for group B; P = 0.264). The freedom from all types of cardiac reintervention was 96.7 % in group A and 89.6 % in group B (P = 0.688). All the patients were free of neurologic symptoms. The authors' perfusion strategy using CCMP with mild hypothermia for repair of CoA with VSD is feasible, safe, and associated with improved postoperative recovery and should be the method of choice.

Fontan conversion templates: patient-specific hemodynamic performance of the lateral tunnel versus the intraatrial conduit with fenestration.

Intraatrial-conduit Fontan is considered a modification of both extracardiac and lateral-tunnel Fontan. In this study, the patient-specific hemodynamic performance of intraatrial-conduit and lateral-tunnel Fontan with fenestration, considered as conversion templates, was investigated based on the authors' patient cohort. Pulsatile computational fluid dynamics simulations were performed using patient-specific models of intraatrial-conduit and lateral-tunnel Fontan patients. Real-time "simultaneous" inferior and superior vena cava, pulmonary artery, and fenestration flow waveforms were acquired from ultrasound. Multiple hemodynamic performance indices were investigated, with particular focus on evaluation of the pulsatile flow performance. Power loss inside the lateral-tunnel Fontan appeared to be significantly higher than with the intraatrial-conduit Fontan for patient-specific cardiac output and normalized connection size. Inclusion of the 4-mm fenestration at a 0.24 L/min mean flow resulted in a lower cavopulmonary pressure gradient and less time-averaged power loss for both Fontan connections. Flow structures within the intraatrial conduit were notability more uniform than within the lateral tunnel. Hepatic flow majorly favored the left lung in both surgical connections: conversion from lateral-tunnel to intraatrial-conduit Fontan resulted in better hemodynamics with less power loss, a lower pressure gradient, and fewer stagnant flow zones along the conduit. This patient-specific computational case study demonstrated superior hemodynamics of intraatrial-conduit Fontan over those of lateral-tunnel Fontan with or without fenestration and improved performance after conversion of the lateral tunnel to the intraatrial conduit. The geometry-specific effect of the nonuniform hepatic flow distribution may motivate new rationales for the surgical design.

Outcome of continuous cerebral and myocardial perfusion under mild hypothermia for aortic coarctation with ventricular septal defect repair.

BACKGROUND: Controversy still exists on the use of the optimal cardiopulmonary bypass (CPB) management in aortic coarctation (CoA) with ventricular septal defect (VSD) repair. We report the outcome of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia. METHOD: This is a retrospective analysis of 60 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Single arterial cannula perfusion technique was used in 15 (25%) patients, and a dual arterial cannula perfusion technique was used in 45 (75%) patients. RESULTS: There were no hospital or late mortalities. Average CPB time was 105 ± 28 minutes, aortic clamp 27 ± 7 minutes, and descending aortic cross-clamp time 24 ± 5 minutes. Average continuous cerebral perfusion flow was 64 ± 8 mL/kg per minute. No patient needed delayed sternal closure. Average duration of ventilation was 38 ± 20 hours, ICU stay 7 ± 3 days, and hospital stay 14 ± 6 days. No patient required revision for bleeding and/or extracorporeal membrane oxygenation support. No neurologic complications were noted. CONCLUSION: A perfusion strategy using CCMP with mild hypothermia for CoA and VSD repair is feasible and safe.

A neonatal rat model of pulmonary vein stenosis.

OBJECTIVES: Pulmonary vein stenosis (PVS), one of the most challenging clinical problems in congenital heart disease, leads to secondary pulmonary arterial hypertension (PAH) and right ventricular (RV) hypertrophy. Due to the lack of a rodent model, the mechanisms underlying PVS and its associated secondary effects are largely unknown, and treatments are minimally successful. This study developed a neonatal rat PVS model with the aim of increasing our understanding of the mechanisms and developing possible treatments for PVS. METHODS: PVS was created at postnatal day 1 (P1) by banding pulmonary veins that receive blood from the right anterior and mid lobes. The condition was confirmed using echocardiography, computed tomography (CT), gross anatomic examination, hematoxylin and eosin (H&E) staining, fibrosis staining, and immunofluorescence. Lung and RV remodeling under the condition of PVS were evaluated using H&E staining, fibrosis staining, and immunofluorescence. RESULTS: At P21, echocardiography revealed a change in wave form and a decrease in pulmonary artery acceleration time-indicators of PAH-at the transpulmonary valve site in the PVS group. CT at P21 showed a decrease in pulmonary vein diameter in the PVS group. At P30 in the PVS group, gross anatomic examination showed pulmonary congestion, H&E staining showed wall thickening and lumen narrowing in the upstream pulmonary veins, and immunofluorescence showed an increase in the smooth muscle layers in the upstream pulmonary veins. In addition, at P30 in the PVS group, lung remodeling was evidenced by hyperemia, thickening of pulmonary small vessel walls and smooth muscle layers, and reduction of the number of alveoli. RV remodeling was evidenced by an increase in RV free wall thickness. CONCLUSIONS: A neonatal rat model of PVS was successfully established, showing secondary lung and RV remodeling. This model may serve as a useful platform for understanding the mechanisms and treatments for PVS.

Volume overload impedes the maturation of sarcomeres and T-tubules in the right atria: a potential cause of atrial arrhythmia following delayed atrial septal defect closure.

Introduction: Adult patients with atrial septal defects (ASD), the most common form of adult congenital heart disease, often die of arrhythmias, and the immaturity of cardiomyocytes contributes significantly to arrhythmias. ASD typically induces a left-to-right shunt, which then leads to the right atrium (RA) volume overload (VO). Whether or not VO contributes to RA cardiomyocyte immaturity and thereby causes arrhythmias in adult patients with ASD remains unclear. Methods: Here, we developed the first neonatal RA VO mouse model by creating a fistula between the inferior vena cava and abdominal aorta on postnatal day 7. RA VO was confirmed by increases in the mean flow velocity, mean pressure gradient, and velocity time integral across the tricuspid valve, and an increase in the RA diameter and RA area middle section. Results: We found that VO decreased the regularity and length of sarcomeres, and decreased the T-element density, regularity, and index of integrity of T-tubules in RA cardiomyocytes, suggesting that the two most important maturation hallmarks (sarcomere and T-tubules) of RA cardiomyocytes were impaired by VO. Accordingly, the calcium handling capacity of cardiomyocytes from postnatal day 21 (P21) RA was decreased by VO. VO caused a significant elongation of the PR interval. The expression of connexin 43 (Cx43) was decreased in RA VO. Moreover, gene ontology (GO) analysis of the downregulated genes in RA demonstrated that there was an abundance of enriched terms associated with sarcomeres and T-tubules exposed to VO. The results were further verified by qRT-PCR. Conclusions: In conclusion, the first neonatal RA VO mouse model was developed; furthermore, using this neonatal RA VO mouse model, we revealed that VO impeded RA sarcomere and T-tubule maturation, which may be the underlying causes of atrial arrhythmias in adult patients with ASD.

The implication of chromosomal abnormalities in the surgical outcomes of Chinese pediatric patients with congenital heart disease.

Background: Copy number variations (CNVs) have been shown to be overrepresented in children with congenital heart disease (CHD). Genetic evaluation of CHD is currently underperformed in China. We sought to determine the occurrence of CNVs in CNV regions with disease-causing potential among a large cohort of Chinese pediatric CHD patients and investigate whether these CNVs could be the important critical modifiers of surgical intervention. Methods: CNVs screenings were performed in 1,762 Chinese children who underwent at least one cardiac surgery. CNV status at over 200 CNV locus with disease-causing potential was analyzed with a high-throughput ligation-dependent probe amplification (HLPA) assay. Results: We found 378 out of 1,762 samples (21.45%) to have at least one CNV and 2.38% of them were carrying multiple CNVs. The detection rates of ppCNVs (pathogenic and likely pathogenic CNVs) were 9.19% (162/1,762), significantly higher than that of the healthy Han Chinese individuals from The Database of Genomic Variants archive (9.19% vs. 3.63%; P = 0.0012). CHD cases with ppCNVs had a significantly higher proportion of complex surgeries compared to CHD patients with no ppCNVs (62.35% vs. 37.63%, P < 0.001). Duration of cardiopulmonary bypass and aortic cross clamp procedures were significantly longer in CHD cases with ppCNVs (all P < 0.05), while no group differences were identified for complications of surgery and one-month mortality after surgery. The detection rate of ppCNVs in the atrioventricular septal defect (AVSD) subgroup was significantly higher than that in other subgroups (23.10% vs. 9.70%, P = 0.002). Conclusions: CNV burden is an important contributor to Chinese children with CHD. Our study demonstrated the robustness and diagnostic efficiency of HLPA method in the genetic screening of CNVs in CHD patients.

Molecular Changes in Prepubertal Left Ventricular Development Under Experimental Volume Overload.

Background: Left ventricular (LV) volume overload (VO), commonly found in patients with chronic aortic regurgitation (AR), leads to a series of left ventricular (LV) pathological responses and eventually irreversible LV dysfunction. Recently, questions about the applicability of the guideline for the optimal timing of valvular surgery to correct chronic AR have been raised in regard to both adult and pediatric patients. Understanding how VO regulates postnatal LV development may shed light on the best timing of surgical or drug intervention. Methods and Results: Prepubertal LV VO was induced by aortocaval fistula (ACF) on postnatal day 7 (P7) in mice. LV free walls were analyzed on P14 and P21. RNA-sequencing analysis demonstrated that normal (P21_Sham vs.P14_Sham) and VO-influenced (P21_VO vs. P14_VO) LV development shared common terms of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) in the downregulation of cell cycle activities and the upregulation of metabolic and sarcomere maturation. The enriched GO terms associated with cardiac condition were only observed in normal LV development, while the enriched GO terms associated with immune responses were only observed in VO-influenced LV development. These results were further validated by the examination of the markers of cell cycle, maturation, and immune responses. When normal and VO-influenced LVs of P21 were compared, they were different in terms of immune responses, angiogenesis, percentage of Ki67-positive cardiomyocytes, mitochondria number, T-tubule regularity, and sarcomere regularity and length. Conclusions: A prepubertal LV VO mouse model was first established. VO has an important influence on LV maturation and development, especially in cardiac conduction, suggesting the requirement of an early correction of AR in pediatric patients. The underlying mechanism may be associated with the activation of immune responses.