Anatomic and physiologic classification of adults with congenital heart disease to predict adverse outcomes: Use of administrative codes compared to clinical staging.

BACKGROUND: The 2018 anatomic physiologic (AP) classification American Heart Association/American College of Cardiology (AHA/ACC) Guidelines for Adults with Congenital Heart Disease (ACHD) encompasses both native and post-operative anatomy and physiology to guide care management. As some physiologic conditions and post-operative states lack specific International Classification of Diseases (ICD) 9- Clinical Modification (CM) and 10-CM codes, an ICD code-based classification approximating the ACHD AP classification is needed for population-based studies. METHODS: A total of 232 individuals, aged ≥ 18 years at the time of a health encounter between January 1, 2010 and December 31, 2019 and identified with at least one of 87 ICD codes for a congenital heart defect were validated through medical chart review. Individuals were assigned one of 4 mutually exclusive modified AP classification categories: (1) severe AB, (2) severe CD, (3) non-severe AB, or (4) non-severe CD, based on native anatomy "severe" or "non-severe" and physiology AB ("none" or "mild") or CD ("moderate" or "severe") by two methods: (1) medical record review, and (2) ICD and Current Procedural Terminology (CPT) code-based classification. The composite outcome was defined as a combination of a death, emergency department (ED) visits, or any hospitalizations that occurred at least 6 months after the index date and was assessed by each modified AP classification method. RESULTS: Of 232 cases (52.2% male, 71.1% White), 28.4% experienced a composite outcome a median of 1.6 years after the index encounter. No difference in prediction of the composite outcome was seen based on modified AP classification between chart review and ICD code-based methodology. CONCLUSION: Modified AP classification by chart review and ICD codes are comparable in predicting the composite outcome at least 6 months after classification. Modified AP classification using ICD code-based classification of CHD native anatomy and physiology is an important tool for population-based ACHD surveillance using administrative data.

Decreased erythrocyte aggregation in Glenn and Fontan: univentricular circulation as a rheologic disease model.

BACKGROUND: In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation. METHODS: We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences. RESULTS: Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation. CONCLUSIONS: Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss. IMPACT: Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.

Pacemaker-Related Factors and Outcomes of Fontan Patients　- Impact of Paced QRS Duration.

BACKGROUND: Permanent pacemaker (PPM) implantation has been identified as a risk factor for morbidity and mortality after Fontan operation. This study investigated the factors associated with outcomes in patients with Fontan physiology who underwent PPM implantation.Methods and Results: We retrospectively reviewed 508 patients who underwent Fontan surgery at Asan Medical Center between September 1992 and August 2022. Of these patients, 37 (7.3%) received PPM implantation. Five patients were excluded, leaving 32 patients, of whom 11 were categorized into the poor outcome group. Poor outcomes comprised death, heart transplantation, and "Fontan failure". Clinical, Fontan procedure-related, and PPM-related factors were compared between the poor and good outcome groups. Ventricular morphology, Fontan procedure-associated factors, pacing mode, high ventricular pacing rate, and time from first arrhythmia to PPM implantation did not differ significantly between the 2 groups. However, the poor outcome group exhibited a significantly longer mean paced QRS duration (P=0.044). Receiver operating characteristic curve analysis revealed a paced QRS duration cut-off value of 153 ms with an area under the curve of 0.73 (P=0.035). CONCLUSIONS: A longer paced QRS duration was associated with poor outcomes, indicating its potential to predict adverse outcomes among Fontan patients.

Evaluación multiparamétrica de la función ventricular derecha en la hipertensión arterial pulmonar asociada a cardiopatías congénitas / Multiparametric evaluation of right ventricular function in pulmonary arterial hypertension associated with congenital heart disease

Introducción y objetivos El pronóstico de los pacientes con cardiopatía congénita e hipertensión arterial pulmonar (HTP) está estrechamente relacionado con la función del ventrículo derecho (VD). Los parámetros de ecocardiografía bidimensional como la deformación miocárdica o el índice de remodelado VD telesistólico (IRVDTS) han surgido para cuantificar la función del VD. Métodos Se estudió de forma prospectiva a 30 paciente de edad 48± 12 años con shunt pretricuspídeo e HTP para investigar la precisión de diversos parámetros ecocardiográficos de estudio de la función del VD (extrusión sistólica del anillo tricúspide, velocidad sistólica pico del anillo tricúspide, ratio de duración sistodiastólica del VD, área de la aurícula derecha, cambio de área fraccional del ventrículo derecho, deformación miocárdica global del ventrículo derecho e IRVDTS) respecto a la fracción de eyección del ventrículo derecho medida por resonancia cardiaca. Resultados En 13 pacientes (43,3%) se observó una fracción de eyección del VD <45%. La deformación longitudinal global del VD (ρ [coeficiente de correlación de Spearman] = −0,75, p=0,001; R2=0,58, p=0,001), área de la aurícula derecha (ρ=−0,74, p <0,0001; R2=0,56, p <0,0001); IRVDTS (ρ=−0,64, p < 0,0001; R2=0,47, p <0,0001), ratio de duración sistodiastólica (ρ=−0,62, p=0,0004; R2=0,47, p <0,0001) y cambio de área fraccional del VD (ρ=0,48, p=0,01; R2=0,37, p <0,0001) se correlacionaron con la fracción de eyección del VD. La deformación longitudinal global del VD, IRVDTS y área de la aurícula derecha fueron predictores de fracción de eyección <45% con la mayor área bajo la curva (0,88; IC95%, 0,71-1,00; 0,88; IC95%, 0,76-1,00 y 0,89; IC95%, 0,77-1,00, respectivamente). Una deformación longitudinal global del VD> −16%, IRVDTS ≥ 1,7 y un área de la aurícula derecha ≥ 22 cm2 predijeron una fracción de eyección del VD <45% con una sensibilidad y especificidad del 87,5 y 85,7%; 76,9 y 88,3%; 92,3 y 82,4%, respectivamente (AU)

Introduction and objectives Outcome in patients with congenital heart diseases and pulmonary arterial hypertension (PAH) is closely related to right ventricular (RV) function. Two-dimensional echocardiographic parameters, such as strain imaging or RV end-systolic remodeling index (RVESRI) have emerged to quantify RV function. Methods We prospectively studied 30 patients aged 48±12 years with pretricuspid shunt and PAH and investigated the accuracy of multiple echocardiographic parameters of RV function (tricuspid annular plane systolic excursion, tricuspid annular peak systolic velocity, RV systolic-to-diastolic duration ratio, right atrial area, RV fractional area change, RV global longitudinal strain and RVESRI) to RV ejection fraction measured by cardiac magnetic resonance. Results RV ejection fraction <45% was observed in 13 patients (43.3%). RV global longitudinal strain (ρ [Spearman's correlation coefficient]=−0.75; P=.001; R2=0.58; P=.001), right atrium area (ρ=−0.74; P <.0001; R2=0.56; P <.0001), RVESRI (ρ=−0.64; P <.0001; R2=0.47; P <.0001), systolic-to-diastolic duration ratio (ρ=−0.62; P=.0004; R2=0.47; P <.0001) and RV fractional area change (ρ=0.48; P=.01; R2=0.37; P <.0001) were correlated with RV ejection fraction. RV global longitudinal strain, RVESRI and right atrium area predicted RV ejection fraction <45% with the greatest area under curve (0.88; 95%CI, 0.71-1.00; 0.88; 95%CI, 0.76-1.00, and 0.89; 95%CI, 0.77-1.00, respectively). RV global longitudinal strain >−16%, RVESRI ≥ 1.7 and right atrial area ≥ 22 cm2 predicted RV ejection fraction <45% with a sensitivity and specificity of 87.5% and 85.7%; 76.9% and 88.3%; 92.3% and 82.4%, respectively. Conclusions RVESRI, right atrial area and RV global longitudinal strain are strong markers of RV dysfunction in patients with pretricuspid shunt and PAH (AU)

Alterations in cardiac output in fetuses with congenital heart disease.

OBJECTIVE: Fetuses with severe congenital heart disease (CHD) have altered blood flow patterns. Prior work to assess fetal combined cardiac output (CCO) is limited by sample size and lack of longitudinal gestational data. Our aim was to evaluate CCO in CHD fetuses to determine whether the presence of single ventricle (SV) physiology or aortic obstruction impacts fetal blood flow and cardiovascular hemodynamics. METHOD: Prospective study including singleton fetuses with CHD (n = 141) and controls (n = 118) who underwent a mid- and late-gestation fetal echocardiogram. Ventricular cardiac output was calculated using the standard computation. Combined cardiac output was derived as the sum of the right and left cardiac outputs and indexed to estimated fetal weight. RESULTS: Fetuses with two ventricle (2V) CHD had significantly higher CCO compared to controls and SV CHD fetuses. Fetuses with SV-CHD had similar CCO compared to controls. Fetuses with 2V-CHD and aortic obstruction had significantly higher CCO than fetuses with SV-CHD and aortic obstruction. CONCLUSION: Our findings suggest that the SV can compensate and increase CCO despite the lack of a second functioning ventricle, however, the degree of compensation may be insufficient to support the increased blood flow needed to overcome the hemodynamic and physiologic alternations seen with severe CHD.

Automatic pediatric congenital heart disease classification based on heart sound signal.

Congenital heart diseases (CHD) are the most common birth defects, and the early diagnosis of CHD is crucial for CHD therapy. However, there are relatively few studies on intelligent auscultation for pediatric CHD, due to the fact that effective cooperation of the patient is required for the acquisition of useable heart sounds by electronic stethoscopes, yet the quality of heart sounds in pediatric is poor compared to adults due to the factors such as crying and breath sounds. This paper presents a novel pediatric CHD intelligent auscultation method based on electronic stethoscope. Firstly, a pediatric CHD heart sound database with a total of 941 PCG signal is established. Then a segment-based heart sound segmentation algorithm is proposed, which is based on PCG segment to achieve the segmentation of cardiac cycles, and therefore can reduce the influence of local noise to the global. Finally, the accurate classification of CHD is achieved using a majority voting classifier with Random Forest and Adaboost classifier based on 84 features containing time domain and frequency domain. Experimental results show that the performance of the proposed method is competitive, and the accuracy, sensitivity, specificity and f1-score of classification for CHD are 0.953, 0.946, 0.961 and 0.953 respectively.

Parametric investigation of an injection-jet self-powered Fontan circulation.

Approximately [Formula: see text] babies are born with only one functioning ventricle and the Fontan is the third and, ideally final staged palliative operation for these patients. This altered circulation is prone to failure with survival rates below [Formula: see text] into adulthood. Chronically elevated inferior vena cava (IVC) pressure is implicated as one cause of the mortality and morbidity in this population. An injection jet shunt (IJS) drawing blood-flow directly from the aortic arch to significantly lower IVC pressure is proposed. A computer-generated 3D model of a 2-4 year old patient with a fenestrated Fontan and a cardiac output of 2.3 L/min was generated. The detailed 3D pulsatile hemodynamics are resolved in a zero-dimensional lumped parameter network tightly-coupled to a 3D computational fluid dynamics model accounting for non-Newtonian blood rheology and resolving turbulence using large eddy simulation. IVC pressure and systemic oxygen saturation were tracked for various IJS-assisted Fontan configurations, altering design parameters such as shunt and fenestration diameters and locations. A baseline "failing" Fontan with a 4 mm fenestration was tuned to have an elevated IVC pressure (+ 17.8 mmHg). Enlargement of the fenestration to 8 mm resulted in a 3 mmHg IVC pressure drop but an unacceptable reduction in systemic oxygen saturation below 80%. Addition of an IJS with a 2 mm nozzle and minor volume load to the ventricle improved the IVC pressure drop to 3.2 mmHg while increasing systemic oxygen saturation above 80%. The salutary effects of the IJS to effectively lower IVC pressure while retaining acceptable levels of oxygen saturation are successfully demonstrated.

Neonatal brain injury influences structural connectivity and childhood functional outcomes.

Neonatal brain injury may impact brain development and lead to lifelong functional impairments. Hypoxic-ischemic encephalopathy (HIE) and congenital heart disease (CHD) are two common causes of neonatal brain injury differing in timing and mechanism. Maturation of whole-brain neural networks can be quantified during development using diffusion magnetic resonance imaging (dMRI) in combination with graph theory metrics. DMRI of 35 subjects with CHD and 62 subjects with HIE were compared to understand differences in the effects of HIE and CHD on the development of network topological parameters and functional outcomes. CHD newborns had worse 12-18 month language (P<0.01) and 30 month cognitive (P<0.01), language (P = 0.05), motor outcomes (P = 0.01). Global efficiency, a metric of brain integration, was lower in CHD (P = 0.03) than in HIE, but transitivity, modularity and small-worldness were similar. After controlling for clinical factors known to affect neurodevelopmental outcomes, we observed that global efficiency was highly associated with 30 month motor outcomes (P = 0.02) in both groups. To explore neural correlates of adverse language outcomes in CHD, we used hypothesis-based and data-driven approaches to identify pathways with altered structural connectivity. We found that connectivity strength in the superior longitudinal fasciculus (SLF) tract 2 was inversely associated with expressive language. After false discovery rate correction, a whole connectome edge analysis identified 18 pathways that were hypoconnected in the CHD cohort as compared to HIE. In sum, our study shows that neonatal structural connectivity predicts early motor development after HIE or in subjects with CHD, and regional SLF connectivity is associated with language outcomes. Further research is needed to determine if and how brain networks change over time and whether those changes represent recovery or ongoing dysfunction. This knowledge will directly inform strategies to optimize neurologic functional outcomes after neonatal brain injury.

Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Patients With Congenital Heart Disease.

Atrioventricular (AV) nodal reentrant tachycardia represents the most common regular supraventricular arrhythmia in humans, and catheter ablation of the so called slow AV nodal pathway has been effectively performed for decades. In patients with congenital heart disease, a combination of different factors makes catheter ablation of AV nodal reentrant tachycardia substrate particularly challenging, including abnormal venous access to intracardiac structures, abnormal intracardiac anatomy, potentially deviant and often unpredictable sites of the specific conduction system, loss of traditional anatomic landmarks, and congenital cardiac surgery that may complicate the access to the AV nodal area. Published experiences have confirmed the efficacy and the relative safety of such procedures when performed by experts, but the risk of complications, in particular AV block, remains non-negligible. A thorough knowledge and understanding of anatomic and electrical specificities according to underlying phenotype are essential in addressing these complex cases. Considering the major consequences associated with AV block in patients with complex congenital heart disease, particularly those without low risk access for transvenous ventricular pacing (eg, single ventricle physiology or Eisenmenger syndrome), the individual risk-benefit ratio should be carefully evaluated. The decision to defer ablation may be the wisest approach in selected patients with either infrequent or hemodynamically tolerated arrhythmias, or when the location of the AV conduction pathways remains uncertain. This narrative review aims to synthetize existing literature on catheter ablation of AV nodal reentrant tachycardia in congenital heart disease, to present main features of common associated pathologies, and to discuss approaches to mapping and safely ablating the slow AV nodal pathway in challenging cases.

Explainable machine learning model for predicting the occurrence of postoperative malnutrition in children with congenital heart disease.

BACKGROUND & AIMS: Malnutrition is persistent in 50%-75% of children with congenital heart disease (CHD) after surgery, and early prediction is crucial for nutritional intervention. The aim of this study was to develop and validate machine learning (ML) models to predict the malnutrition status of children with CHD. We used explainable ML methods to provide insight into the model's predictions and outcomes. METHODS: This prospective cohort study included consecutive children with CHD admitted to the hospital from December 2017 to May 2020. The cohort data were divided into the training and test data sets based on the follow-up time. The outcome of the study was CHD child malnutrition 1 year after surgery, the primary outcome was an underweight status, and the secondary outcomes were stunted and wasting status. We used five ML algorithms with multiple features to construct prediction models, and the performance of these ML models was measured by an area under the receiver operating characteristic curve (AUC) analysis. We also used the permutation importance and SHapley Additive exPlanations (SHAP) to determine the importance of the selected features and interpret the ML models. RESULTS: We enrolled 536 children with CHD who underwent complete repair. The proportions of children with an underweight, stunted, or wasting status 1 year after surgery were 18.1% (97/536), 12.1% (65/536), and 17.5% (94/536), respectively. All patients contributed to the generation of 115 useable features, which allowed us to build models to predict malnutrition. Five prediction algorithms were used, and the XGBoost model achieved the greatest AUC in all outcomes. The results obtained from the permutation importance and SHAP analyses showed that the 1-month postoperative WAZ-score, discharge WAZ score and preoperative WAZ score were the top 3 important features in predicting an underweight status in the XGBoost algorithm. Regarding the stunted status, the top 3 important features were the 1-month postoperative HAZ score, discharge HAZ score, and aortic clamping time. Regarding the wasting status, the top 3 important features were the hospital length of stay, formula intake, and discharge WHZ-score. We also used a narrative case report as an example to describe the clinical manifestations and predicted the primary outcomes of two children. CONCLUSIONS: We developed an ML model (XGBoost) that provides accurate early predictions of malnutrition 1-year postoperatively in children with CHD. Because the ML model is explainable, it may better enable clinicians to better understand the reasoning underlying the outcome. Our study could aid in determining individual treatment and nutritional follow-up strategies for children with CHD.

Exercise capacity after total cavopulmonary anastomosis: a longitudinal paediatric and adult study.

AIMS: Fontan palliation is a surgical strategy for patients with complex congenital heart disease, in whom biventricular circulation cannot be achieved. Long-term survival is negatively affected by the absence of sub-pulmonary ventricle and increased systemic venous pressure. Exercise capacity is a known predictor of overall survival and quality of life in congenital heart defects. We aim to track individual trends of peak oxygen uptake (V̇O2 peak) after total cavopulmonary connection (TCPC), identify predictors of deterioration, and derive a disease-specific reference V̇O2 peak dataset. METHODS AND RESULTS: A retrospective study of serial cardiopulmonary exercise testing (CPET) data, gathered from all patients who underwent TCPC in the Czech Republic between 1992 and 2016. Of 354 consecutive patients with TCPC, 288 (81.4%) patients underwent one or more CPETs yielding 786 unique V̇O2 peak values used as a reference dataset. Longitudinal data were available in 206 (58.2%) patients, who underwent a median (inter-quartile range) of 3.0 (2.0-5.0) CPETs over a mean (standard deviation) of 8.9 (5.5) years. The decline of exercise capacity with age was linear and not faster than in healthy peers (P = 0.47), but relative values of V̇O2 peak in TCPC patients were 12.6 mL/min/kg lower. Single ventricular morphology and pulmonary artery size had no significant influence on the exercise capacity dynamics. V̇O2 peak decline correlated negatively with the trend of body mass index z-score (P = 0.006) and was faster in women than men (P = 0.008). CONCLUSIONS: Total cavopulmonary connection patients have significantly reduced exercise capacity. The age-related decline paralleled the healthy population and correlated negatively with the body mass index trend. The presented V̇O2 peak reference dataset may help the clinicians to grade the severity of exercise capacity impairment in individual TCPC patients.

Corpus callosum size by neurosonography in fetuses with congenital heart defect and relationship with expected pattern of brain oxygen supply.

OBJECTIVE: To evaluate corpus callosum (CC) size by neurosonography (NSG) in fetuses with an isolated major congenital heart defect (CHD) and explore the association of CC size with the expected pattern of in-utero oxygen supply to the brain. METHODS: A total of 56 fetuses with postnatally confirmed isolated major CHD and 56 gestational-age-matched controls were included. Fetuses with CHD were stratified into two categories according to the main expected pattern of cerebral arterial oxygen supply: Class A, moderately to severely reduced oxygen supply (left outflow tract obstruction and transposition of the great arteries) and Class B, near normal or mildly impaired oxygenated blood supply to the brain (other CHD). Transvaginal NSG was performed at 32-36 weeks in all fetuses to evaluate CC length, CC total area and areas of CC subdivisions in the midsagittal plane. RESULTS: CHD fetuses had a significantly smaller CC area as compared to controls (7.91 ± 1.30 vs 9.01 ± 1.44 mm2 ; P < 0.001), which was more pronounced in the most posterior part of the CC. There was a significant linear trend for reduced CC total area across the three clinical groups, with CHD Class-A cases showing more prominent changes (controls, 9.01 ± 1.44 vs CHD Class B, 8.18 ± 1.21 vs CHD Class A, 7.53 ± 1.33 mm2 ; P < 0.05). CONCLUSIONS: Fetuses with major CHD had a smaller CC compared with controls, and the difference was more marked in the CHD subgroup with expected poorer brain oxygenation. Sonographic CC size could be a clinically feasible marker of abnormal white matter development in CHD. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Biventricular conversion after Fontan completion: A preliminary experience.

OBJECTIVE: To assess the feasibility and outcomes of biventricular conversion following takedown of Fontan circulation. METHODS: Retrospective analysis of patients who had takedown of Fontan circulation and conversion to biventricular circulation at a single center from September 2007 to April 2020. Failing Fontan physiology was defined as Fontan circulation pressure >15 mm Hg and/or the presence of associated complications. RESULTS: Biventricular conversion was performed in 23 patients at a median age of 10.0 (7.5-13.0) years. Indications included failing Fontan physiology in 15 (65%) and elective takedown in 8 (35%) patients. A subset of patients (n = 6) underwent procedures for staged recruitment of the nondominant ventricle before conversion. Median z score of end-diastolic volume of borderline ventricle before takedown was -2.3 (-3.3, -1.3). Hypoplastic left heart syndrome (P < .01) and sub-/aortic stenosis (P < .01) were more common in these patients. Biventricular conversion with or without staged ventricular recruitment led to a significant increase in indexed end-diastolic volume (P < .01), indexed end-systolic volume (P < .01), and ventricular mass (P < .01) of the nondominant ventricle (14 right, 9 left ventricle). There were 5 (22%) deaths (1 [4%] early death). All who underwent elective biventricular conversion survived, whereas 2-year survival rate for patients with a failing Fontan circulation was 72.7% (95% confidence interval, 37%-90%). The overall, 3-year reoperation-free survival was 86.7% (95% confidence interval, 56%-96%). Left dominant atrioventricular canal defect (P < .01) and early era of biventricular conversion (P = .02) were significant predictors for mortality. CONCLUSIONS: A primary as well as a staged biventricular conversion is feasible in patients who have had previous Fontan procedure. Although this provides an alternative to transplantation in patients with failing Fontan, outcomes are worse in those with failing Fontan compared with elective takedown of Fontan circulation. Optimal timing needs further evaluation.

Surgery for severe congenital heart diseases in children from developing nations.

BACKGROUND: Children with severe congenital heart disease (CHD) are rarely treated in developing countries and have very little to no chance to survive in their local environment. Mécénat Chirurgie Cardiaque (MCC) flies to France children with CHD from developing countries. This report focuses on the early, mid, and late outcomes of 531 children with severe CHD sent to MCC for surgery from 1996 to 2019. METHODS: The inclusion criteria were based on diagnosis and not on procedure. MCC is present in 66 countries and has developed a robust staff, including 12 permanent employees and 700 volunteers, with 350 host families based in France, 120 local correspondents, and 100 local physicians. Since 1996, MCC has organized a basic training of local pediatric cardiologists yearly, offering a free 1-month training course. Over time, MCC could count on a pool of doctors trained in basic pediatric cardiology. Flights were secured by the Aviation Sans Frontieres Foundation. Nine French centers performed the surgeries. A robust follow-up was conducted in all the nations where MCC operates. RESULTS: The most frequent pathologies were single ventricle (n = 126), double-outlet right ventricle (n = 116), pulmonary atresia with ventricular septal defect (n = 68), transposition of the great arteries with ventricular septal defect and transposition of the great arteries with intact ventricular septum (n = 61), arterial trunk (n = 39), transposition of the great arteries with ventricular septal defect and left ventricle outflow tract obstruction (n = 35), complete atrioventricular septal defect (n = 18), congenitally corrected transposition of the great arteries (n = 16), and so on. The median age was 5.4 years (range, 1 month-26 years). The mean perioperative mortality was 5.5% (29 out of 531) (95% confidence limit, 3.5%-7.4%). The follow-up was 91.3%, with a mean follow-up of 5.1 years. The global actuarial survival at 5, 10, and 15 years was, respectively, 85%, 83%, and 74%. There was a significant higher late mortality for patients surviving only with a Blalock-Taussig shunt (P = .001). CONCLUSIONS: Operating on 531 children with severe CHD from developing nations was achieved with satisfactory early and long-term results. Children with severe CHD are rarely operated on in developing nations. Programs like MCC's offer a viable option to save these children born with severe CHD.