Identifying influence factors and thresholds of the next day's pollen concentration in different seasons using interpretable machine learning.

The prevalence of pollen allergies is a pressing global issue, with projections suggesting that half of the world's population will be affected by 2050 according to the estimation of the World Health Organization (WHO). Accurately forecasting pollen allergy risks requires identifying key factors and their thresholds for aerosol pollen. To address this, we developed a technical framework combining advanced machine learning and SHapley Additive exPlanations (SHAP) technology, focusing on Beijing. By analyzing meteorological data and vegetation phenology, we identified the factors influencing next-day's pollen concentration (NDP) in Beijing and their thresholds. Our results highlight vegetation phenology data from Synthetic Aperture Radar (SAR), temperature, wind speed, and atmospheric pressure as crucial factors in spring. In contrast, the Normalized Difference Vegetation Index (NDVI), air temperature, and wind speed are significant in autumn. Leveraging SHAP technology, we established season-specific thresholds for these factors. Our study not only confirms previous research but also unveils seasonal variations in the relationship between radar-derived vegetation phenology data and NDP. Additionally, we observe seasonal fluctuations in the influence patterns and threshold values of daily air temperatures on NDP. These insights are pivotal for improving pollen concentration prediction accuracy and managing allergic risks effectively.

EGFR of platelet regulates macrophage activation and bacterial phagocytosis function.

BACKGROUND: Beyond their crucial role in hemostasis, platelets possess the ability to regulate inflammation and combat infections through various mechanisms. Stringent control of macrophage activation is essential during innate immune responses in sepsis. Macrophages are considered crucial phagocytic cells that aid in the elimination of pathogens. Platelet interactions with monocytes-macrophages are known to be significant in the response against bacterial infections, but the primary mediator driving these interactions remains unclear. EGFR plays critical role in the regulation of inflammation and infection through various mechanisms. RESULTS: The overexpression of platelets by thrombopoietin (TPO) leads to the sequestration of both pro-inflammatory (IL-6/IL-1) and anti-inflammatory (IL-10) cytokines in the organ tissue of septic mice. Epidermal growth factor receptor (EGFR) is critical for platelet activation in sepsis. EGFR-licensed platelets enhance macrophage immune function, including the production of reactive oxygen species (ROS) and the clearance of bacteria. Platelet EGFR also induces M1 macrophage polarization by increasing the expression of inducible nitric oxide synthase (iNOS) and CD64. CONCLUSION: EGFR can activate platelet immune function. Moreover, activated platelets efficiently regulate bacterial phagocytosis and pro-inflammatory function of macrophages through an EGFR-dependent pathway.

Siglec-F+ neutrophils in the spleen induce immunosuppression following acute infection.

Background: The mechanisms underlying the increased mortality of secondary infections during the immunosuppressive phase of sepsis remain elusive. Objectives: We sought to investigate the role of Siglec-F+ neutrophils on splenic T lymphocytes in the immunosuppressed phase of sepsis and on secondary infection in PICS mice, and to elucidate the underlying mechanisms. Methods: We established a mouse model of sepsis-induced immunosuppression followed by secondary infection with LPS or E. coli. The main manifestation of immunosuppression is the functional exhaustion of splenic T lymphocytes. Treg depletion reagent Anti-IL-2, IL-10 blocker Anti-IL-10R, macrophage depletion reagent Liposomes, neutrophil depletion reagent Anti-Ly6G, neutrophil migration inhibitor SB225002, Siglec-F depletion reagent Anti-Siglec-F are all used on PICS mice. The function of neutrophil subsets was investigated by adoptive transplantation and the experiments in vitro. Results: Compared to other organs, we observed a significant reduction in pro-inflammatory cytokines in the spleen, accompanied by a marked increase in IL-10 production, primarily by infiltrating neutrophils. These infiltrating neutrophils in the spleen during the immunosuppressive phase of sepsis undergo phenotypic change in the local microenvironment, exhibiting high expression of neutrophil biomarkers such as Siglec-F, Ly6G, and Siglec-E. Depletion of neutrophils or specifically targeting Siglec-F leads to enhance the function of T lymphocytes and a notable improvement in the survival of mice with secondary infections. Conclusions: We identified Siglec-F+ neutrophils as the primary producers of IL-10, which significantly contributed to T lymphocyte suppression represents a novel finding with potential therapeutic implications.

Coronary artery lesions are associated with adverse cardiac events in children undergoing supravalvular aortic stenosis repair.

OBJECTIVES: The aim of this study was to identify the prevalence and anatomic characteristics of coronary artery lesions and their associated postoperative risk in patients undergoing supravalvular aortic stenosis repair. METHODS: The association between structural risk factors, postoperative ST-segment changes, and major adverse cardiac events was explored using logistic regression and the Fisher's exact test. RESULTS: In 51 consecutive patients with supravalvular aortic stenosis treated between 2000 and 2017, a total of 48 coronary lesions were identified in 27 patients (53%). Prominent ostial ridge (type I) was the most common coronary lesion, followed by small ostium with (IIIb) or without (IIIa) diffuse long-segment coronary narrowing, and adhesion of the coronary cusp (type II). There were 54 concomitant coronary procedures, including 43 primary corrections and 11 revisions. Thirty-three patients underwent supravalvular aortic stenosis repair with a bifurcated patch, of which 13 (39.4%) had right coronary artery distortion/kinking requiring patch plication (n = 8) and reimplantation (n = 5). Postoperative major adverse cardiac events (MACE) occurred in 9 patients (17.6%), including 3 deaths, 4 needing mechanical circulatory support, and 6 experiencing ventricular arrhythmias. Twenty-two patients (43.1%) had postoperative ST-segment changes, including 13 early changes that resolved within 24 h and 9 persistent changes lasting >24 h. Patients with type III lesions were associated with postoperative persistent ST-segment change (P = 0.04) and these lesions independently predicted postoperative MACE (P = 0.02). Patients with pre-existing coronary lesions were at elevated risk of right coronary artery distortion/kinking (P = 0.045). CONCLUSIONS: The prevalence of ST-segment changes and MACE is high in patients undergoing supravalvular aortic stenosis repair. The preoperative presence of complex coronary lesions is the most important predictor for postoperative major adverse cardiac events.

Postoperative intra-abdominal hypertension predicts worse hospital outcomes in children after cardiac surgery: a pilot study†.

OBJECTIVES: Our goal was to determine the incidence and characteristics of postoperative intra-abdominal hypertension (IAH) in paediatric patients undergoing open-heart surgery. METHODS: This single-centre study included consecutive children (aged <16 years) who underwent open-heart surgery between July 2020 and February 2021. Patients who entered the study were followed until in-hospital death or hospital discharge. The study consisted of 2 parts. Part I was a prospective observational cohort study that was designed to discover the association between exposures and IAH. Postoperative intra-abdominal pressure was measured immediately after admission to the intensive care unit and every 6 h thereafter. Part II was a cross-sectional study to compare the hospital-related adverse outcomes between the IAH and the no-IAH cohorts. RESULTS: Postoperatively, 24.7% (38/154) of the patients exhibited IAH, whereas 3.9% (6/154) developed abdominal compartment syndrome. The majority (29/38, 76.3%) of IAH cases occurred within the first 24 h in the intensive care unit. Multivariable analysis showed that the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score [odds ratio (OR) = 1.86, 95% confidence interval (CI) 1.23-2.83, P = 0.004], right-sided heart lesion (OR = 5.60, 95% CI 2.34-13.43, P < 0.001), redo sternotomy (OR = 4.35, 95% CI 1.64-11.57, P = 0.003), high baseline intra-abdominal pressure (OR = 1.43, 95% CI 1.11-1.83, P = 0.005), prolonged cardiopulmonary bypass duration (OR = 1.01, 95% CI 1.00-1.01, P = 0.005) and deep hypothermic circulatory arrest (OR = 5.14, 95% CI 1.15-22.98, P = 0.032) were independent predictors of IAH occurrence. IAH was associated with greater inotropic support (P < 0.001), more gastrointestinal complications (P = 0.001), sepsis (P = 0.003), multiple organ dysfunction syndrome (P < 0.001) and prolonged intensive care unit stay (z = -4.916, P < 0.001) and hospitalization (z = -4.710, P < 0.001). The occurrence of a composite outcome (P = 0.009) was significantly increased in patients with IAH. CONCLUSIONS: IAH is common in children undergoing cardiac surgery and is associated with worse hospital outcomes. Several factors may be associated with the development of IAH, including basic cardiac physiology and perioperative factors. TRIAL INFORMATION: This study was registered in the Chinese Clinical Trial Registry (Trial number: ChiCTR2000034322)URL site: https://www.chictr.org.cn/hvshowproject.html?id=41363&v=1.4.

Congenital dual anterior interventricular artery.

Dual anterior interventricular artery is a rare type of CHD. We reported a fifteen-year-old girl who underwent CT angiography that demonstrated one anterior interventricular artery from aorta and another from pulmonary artery.

Epithelial SIRT6 governs IL-17A pathogenicity and drives allergic airway inflammation and remodeling.

Dysregulation of IL-17A is closely associated with airway inflammation and remodeling in severe asthma. However, the molecular mechanisms by which IL-17A is regulated remain unclear. Here we identify epithelial sirtuin 6 (SIRT6) as an epigenetic regulator that governs IL-17A pathogenicity in severe asthma. Mice with airway epithelial cell-specific deletion of Sirt6 are protected against allergen-induced airway inflammation and remodeling via inhibiting IL-17A-mediated inflammatory chemokines and mesenchymal reprogramming. Mechanistically, SIRT6 directly interacts with RORγt and mediates RORγt deacetylation at lysine 192 via its PPXY motifs. SIRT6 promotes RORγt recruitment to the IL-17A gene promoter and enhances its transcription. In severe asthma patients, high expression of SIRT6 positively correlates with airway remodeling and disease severity. SIRT6 inhibitor (OSS_128167) treatment significantly attenuates airway inflammation and remodeling in mice. Collectively, these results uncover a function for SIRT6 in regulating IL-17A pathogenicity in severe asthma, implicating SIRT6 as a potential therapeutic target for severe asthma.

A cohort study to investigate the potential indicators for prenatal echocardiographic detection of suspected coarctation of the aorta.

Objectives: Suspected coarctation of the aorta (CoA) is a common fetal echocardiographic presentation. However, the prenatal findings did not indicate a satisfied accuracy in determining the truly CoA after birth, which made the prenatal diagnosis of CoA still as a critical challenge with high false positive rate. Thus, this research is aimed to distinguish the potential prenatal parameters influencing the fetal echocardiographic images and enhance the true positive diagnostic rate of CoA fetuses which require early clinical intervention in postnatal life. Methods: A retrospective study had been designed and fetuses with suspected with CoA had been included from Jan 2016 to Dec 2021 in our center. The fetal echocardiography and related clinical information had been collected. And the postnatal diagnosis had been reached by echocardiography or CTA. Then, all the parameters had been analyzed by univariate analysis, and a multivariate logistic regression analysis was further involved to determine the independent parameters influencing the accuracy of diagnosis CoA fetuses. Moreover, such results had been validated by nomogram analysis and ROC curve. Results: Among the included 44 liveborn infants who presented suspected CoA in fetal cardiac screening, 18 cases had been proved to be CoA postnatally (Group P). The true positive rate for this study was 40.9% (18/44). The abnormal atrial hemodynamic status (AAHs) and the gestational week of delivery (GWoD) were associated with the postnatal CoA confirmation among prenatal suspected fetuses. The ROC curve of predicting probability of the mode combined with two independent factors of absence of AAH and GWoD (AUC = 0.880, 95% CI 0.763-0.997) presented a satisfied efficacy in distinguishing postnatal positive CoA diagnosis. The nomogram plot had been be utilized in CoA prediction (model likelihood ratio test, p < 0.0001). Conclusions: AAH and GWoD had been identified as independent factors of predictive accuracy in detecting postnatal CoA among prenatal suspected fetuses. The prediction mode based on nomogram scores could be used to predict the risk of occurring CoA fetuses.

A novel compound heterozygous variant in ALPK3 induced hypertrophic cardiomyopathy: a case report.

Background: Malignant hypertrophic cardiomyopathy (HCM) phenotypes have potential risks of severe heart failure, fatal arrhythmia, and sudden cardiac death. Therefore, it is critical to predict the clinical outcomes of these patients. It was reported recently that the alpha kinase 3 (ALPK3) gene was involved in the occurrence of HCM. Herein we reported a girl with HCM, while whole-exome sequencing found novel compound heterozygous variants in ALPK3 gene, which identified a potential association. Case presentation: We reported a 14-year-girl who suffered from clinical manifestations of cardiac failure, with sudden cardiac arrest before admission. The heartbeat recovered after cardiopulmonary resuscitation, though she remained unconscious without spontaneous breath. The patient stayed comatose when she was admitted. Physical examination indicated enlargement of the heart boundary. Laboratory results revealed a significant increment of myocardial markers, while imaging demonstrated hypertrophy of the left heart and interventricular septum. Whole-exome sequencing (WES) identified a compound heterozygous variant in ALPK3 gene consisting of c.3907_3922del and c.2200A>T, which was inherited from her parents. Both variants (p.G1303Lfs*28 and p.R734*) were disease-causing evaluated by MutationTaster (probability 1.000). The crystal structure of the complete amino acid sequence is predicted and evaluated by AlphaFold and SWISS-MODEL software (July, 2022), which revealed three domains. Moreover, both variants resulted in a wide protein-truncating variant and damaged protein function. Thus, a novel compound heterozygous variant in ALPK3 associated with HCM was diagnosed. Conclusion: We described a young patient with ALPK3-associated HCM who experienced sudden cardiac arrest. Through WES, we identified a compound heterozygous variant in the ALPK3 gene, c.3907_3922del and c.2200A>T, which were inherited from the patient's parents and resulted in a truncated protein, indirectly causing the symptoms of HCM. In addition, WES provided clues in evaluating potential risks of gene variants on fatal clinical outcomes, and the nonsense and frameshift variants of ALPK3 were related to adverse clinical outcomes in HCM patients, which required implantable cardioverter defibrillator (ICD) timely.

The Molecular Role of Immune Cells in Dilated Cardiomyopathy.

Dilated cardiomyopathy (DCM) is a rare and severe condition characterized by chamber dilation and impaired contraction of the left ventricle. It constitutes a fundamental etiology for profound heart failure and abrupt cardiac demise, rendering it a prominent clinical indication for heart transplantation (HTx) among both adult and pediatric populations. DCM arises from various etiologies, including genetic variants, epigenetic disorders, infectious insults, autoimmune diseases, and cardiac conduction abnormalities. The maintenance of cardiac function involves two distinct types of immune cells: resident immune cells and recruited immune cells. Resident immune cells play a crucial role in establishing a harmonious microenvironment within the cardiac tissue. Nevertheless, in response to injury, cardiomyocytes initiate a cytokine cascade that attracts peripheral immune cells, thus perturbing this intricate equilibrium and actively participating in the initiation and pathological remodeling of dilated cardiomyopathy (DCM), particularly during the progression of myocardial fibrosis. Additionally, immune cells assume a pivotal role in orchestrating the inflammatory processes, which are intimately linked to the prognosis of DCM. Consequently, understanding the molecular role of various immune cells and their regulation mechanisms would provide an emerging era for managing DCM. In this review, we provide a summary of the most recent advancements in our understanding of the molecular mechanisms of immune cells in DCM. Additionally, we evaluate the effectiveness and limitations of immunotherapy approaches for the treatment of DCM, with the aim of optimizing future immunotherapeutic strategies for this condition.

Modified central shunt in pulmonary atresia with diminutive pulmonary arteries.

The commonly used central shunt (i.e. direct connection of the divided main pulmonary artery to the ascending aorta) to facilitate the growth of the diminutive branch pulmonary artery in patients with pulmonary atresia with major aortopulmonary collateral arteries can cause main pulmonary artery distortion, and subsequent disproportional branch pulmonary artery flow and growth. This report describes a novel technique of shunt construction to minimize pulmonary artery torque and tension by using a modified central shunt constructed from autologous pericardium that is anastomosed in an end-to-side fashion to the lateral aspect of the ascending aorta. This shunt will serve as an intermediary conduit to facilitate the main pulmonary artery anastomosis while minimizing torque and tension on the main pulmonary artery. The tension-free connection between the main pulmonary artery and the aorta enabled by the modified central shunt supports proportional pulmonary artery flow and growth in patients with pulmonary atresia, ventricular septal defect, or multiple aortopulmonary collateral arteries and concomitant diminutive native pulmonary arteries.

METTL3-mediated m6A mRNA methylation regulates neutrophil activation through targeting TLR4 signaling.

N6-methyladenosine (m6A) modification accounts for the most prevalent mRNA internal modification and has emerged as a widespread regulatory mechanism in multiple physiological processes. We address a role of methyltransferase-like protein 3 (METTL3) in neutrophil activation. METTL3 controls neutrophil release from bone marrow to circulation through surface expression of CXC chemokine receptor 2 (CXCR2) in a Toll-like receptor 4 (TLR4) signaling-dependent manner in lipopolysaccharide (LPS)-induced endotoxemia. We show that the mRNA of TLR4 is modified by m6A, exhibiting increased translation and slowed degradation simultaneously, leading to elevated protein levels of TLR4, which eventually promotes the TLR4 signaling activation of neutrophil. The reduced expression of TLR4 lowers cytokine secretion in METTL3-deleted neutrophils upon LPS stimulation through TLR4/Myd88/nuclear factor κB (NF-κB) signaling. Collectively, these data demonstrate that METTL3 modulation of TLR4 expression is a critical determinant of neutrophil activation in endotoxemia.

Establishment of induced pluripotent stem cell lines from an ARVC patient carrying a heterozygous variant in LAMA2 gene.

Using peripheral blood mononuclear cell (PBMC) reprogramming technology, a human-induced pluripotent stem cell (iPSC) line was produced from a patient who presents classic clinical features of arrhythmogenic right ventricular cardiomyopathy (ARVA) and carries a de novo laminin subunit alpha 2 (LAMA2) heterozygous mutation (NM_000426.3: c.8842G > A, p.G2948S). This mutation was not inherited from his parents, who also present normal cardiac phenotype. This iPSC line demonstrates a normal karyotype. Pluripotency and differentiation capacity has been confirmed in vitro. This cell line can help in efforts to understand the pathogenic mechanism between LAMA2 mutation and ARVC.

EGFR promotes the apoptosis of CD4+ T lymphocytes through TBK1/Glut1 induced Warburg effect in sepsis.

INTRODUCTION: Sepsis-induced apoptosis leads to lymphopenia including the decrease of CD4+ T cells thus favoring immunosuppression. OBJECTIVES: Although epidermal growth factor receptor (EGFR) inhibitors significantly improve the survival rate of septic mice, the effect of EGFR on the function and metabolism of CD4+ T cells in sepsis remained unknown. METHODS: CD4+ T cells from septic mice and patients were assessed for apoptosis, activation, Warburg metabolism and glucose transporter 1 (Glut1) expression with or without the interference of EGFR activation. RESULTS: EGFR facilitates CD4+ T cell activation and apoptosis through Glut1, which is a key enzyme that controls glycolysis in T cells. EGFR, TANK binding kinase 1 (TBK1) and Glut1 form a complex to facilitate Glut1 transportation from cytoplasm to cell surface. Both the levels of membrane expression of EGFR and Glut1 and the activation levels of CD4+ T cells were significantly higher in patients with sepsis as compared with healthy subjects. CONCLUSION: Our data demonstrated that through its downstream TBK1/Exo84/RalA protein system, EGFR regulates Glut1 transporting to the cell surface, which is a key step for inducing the Warburg effect and the subsequent cellular activation and apoptosis of CD4+ T lymphocytes and may eventually affect the immune functional status, causing immune cell exhaustion in sepsis.

EGFR tyrosine kinase activity and Rab GTPases coordinate EGFR trafficking to regulate macrophage activation in sepsis.

EGFR phosphorylation is required for TLR4-mediated macrophage activation during sepsis. However, whether and how intracellular EGFR is transported during endotoxemia have largely been unknown. Here, we show that LPS promotes high levels cell surface expression of EGFR in macrophages through two different transport mechanisms. On one hand, Rab10 is required for EEA1-mediated the membrane translocation of EGFR from the Golgi. On the other hand, EGFR phosphorylation prevents its endocytosis in a kinase activity-dependent manner. Erlotinib, an EGFR tyrosine kinase inhibitor, significantly reduced membrane EGFR expression in LPS-activated macrophage. Mechanistically, upon LPS induced TLR4/EGFR phosphorylation, MAPK14 phosphorylated Rab7a at S72 impaired membrane receptor late endocytosis, which maintains EGFR membrane localization though blocking its lysosomal degradation. Meanwhile, Rab5a is also involved in the early endocytosis of EGFR. Subsequently, inhibition of EGFR phosphorylation switches M1 phenotype to M2 phenotype and alleviates sepsis-induced acute lung injury. Mechanistic study demonstrated that Erlotinib suppressed glycolysis-dependent M1 polarization via PKM2/HIF-1ɑ pathway and promoted M2 polarization through up-regulating PPARγ induced glutamine metabolism. Collectively, our data elucidated a more in-depth mechanism of macrophages activation, and provided stronger evidence supporting EGFR as a potential therapeutic target for the treatment of sepsis.

Aortopulmonary communication between the arterial trunks in tetralogy of Fallot with pulmonary atresia.

We reported a case of a 14-year-old tetralogy of Fallot/pulmonary atresia patient, where a rare tubular aortopulmonary communication between the arterial trunks allowed for well-growth of the pulmonary vasculature. The patient underwent successful one-stage unifocalization, right ventricle-pulmonary artery conduit and ventricular septal defect closure. The tubular communication was considered an aortopulmonary window as opposed to the major aortopulmonary collateral, based on its exclusively intrapericardial course. We highlighted the importance of cross-section imaging in diagnosis and surgical decision-making in such situations.

A rare case of arrhythmogenic right ventricular cardiomyopathy associated with LAMA2 mutation: A case report and literature review.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable heart muscle disorder that predominantly affects the right ventricle. Mutations in genes that encode components of desmosomes, the adhesive junctions that connect cardiomyocytes, are the predominant cause of ARVC. A case with novel heterozygous mutation in the LAMA2 gene is reported here. The protein encoded by LAMA2 gene is the α2 chain of laminin-211 protein, which establishes a stable relationship between the muscle fiber membrane and the extracellular matrix. We explored the potential mechanism and the relationship between the mutation and ARVC. Case Presentation: At the age of 8, the patient developed syncope and palpitation after exercise. Dynamic electrocardiogram recorded continuous premature ventricular beats, and MRI showed the right ventricle was significantly enlarged and there were many localized distensions at the edge of the right ventricular wall. The patient was diagnosed with ARVC and received heart transplantation at the age of 14 due to severe heart dysfunction. The myocardial histological pathological staining revealed a large amount of fibrosis and adipose migration. Whole exome sequencing (WES) identified the heterozygous mutation in the LAMA2 gene [NM_000426.3: c.8842G > A (p.G2948S)]. This is the first report of these variants. Analysis was performed on genetic disorders to reveal splice site changes and damage to protein structure. LAMA2 p.G2948S predicted unstable protein structure and impaired function. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were established. RNA-seq and the western blot were performed on IPSC-CMs to explore the ARVC-related signaling pathway. Conclusion: This is the first case report to describe an ARVC phenotype in patients possessing a novel LAMA2 c.8842G > A (p.G2948S) mutation. Our results aid in understanding of the pathogenesis of ARVC. The molecular mechanism of LAMA2 leading to ARVC disease still needs further study.

Clinical translation of surgical simulated closure of a ventricular septum defect.

OBJECTIVES: To demonstrate that improvement in technical performance of congenital heart surgical trainees during ventricular septum defect (VSD) closure simulation translates to better patient outcomes. METHODS: Seven trainees were divided into 2 groups. Experienced-fellows group included 4 senior trainees who had performed >5 VSD closures. Residents group consisted of 3 residents who had never performed a VSD closure. Experienced-fellows completed 3 VSD closures on real patients as a pretest. Both groups participated in a 4-week simulation requiring each participant to complete 2 VSD closures on three-dimensional printed models per week. One month later, all trainees returned for a post-test operation in real patients. All performances were recorded, blinded and scored independently by 2 cardiac surgeons using the validated Hands-On Surgical Training-Congenital Heart Surgery (HOST-CHS). Predefined surgical outcomes were analysed. RESULTS: The median HOST-CHS score increased significantly from week 1 to 4 [50 (39, 58) vs 73 (65, 74), P < 0.001] during simulation. The improvement in the simulation of experienced-fellows successfully transferred to skill acquisition [HOST-CHS score 72.5 (71, 74) vs 54 (51, 60), P < 0.001], with better patients outcomes including shorter total cross-clamp time [pretest: 86 (70, 99) vs post-test: 60 (53, 64) min, P = 0.006] and reduced incidence of major patch leak requiring multiple pump runs [pretest: 4/11 vs post-test: 0/9, P = 0.043]. After simulation, the technical performance and surgical outcomes of Residents were comparable to Experienced-fellows in real patients, except for significantly longer cross-clamp time [Residents: 76.5 (71.7, 86.8) vs Experienced-fellows: 60 (53, 64) min, P = 0.002]. CONCLUSIONS: Deliberate practice using simulation translates to better performance and surgical outcomes in real patients. Residents who had never completed a VSD closure could perform the procedures just as safely and effectively as their senior colleagues following simulation.