Pathology of explanted pediatric hearts: An 11-year study. Population characteristics and implications for outcomes.

BACKGROUND: As more pediatric patients become candidates for heart transplantation (HT), understanding pathological predictors of outcome and the accuracy of the pretransplantation evaluation are important to optimize utilization of scarce donor organs and improve outcomes. The authors aimed to investigate explanted heart specimens to identify pathologic predictors that may affect cardiac allograft survival after HT. METHODS: Explanted pediatric hearts obtained over an 11-year period were analyzed to understand the patient demographics, indications for transplant, and the clinical-pathological factors. RESULTS: In this study, 149 explanted hearts, 46% congenital heart defects (CHD), were studied. CHD patients were younger and mean pulmonary artery pressure and resistance were significantly lower than in cardiomyopathy patients. Twenty-one died or underwent retransplantation (14.1%). Survival was significantly higher in the cardiomyopathy group at all follow-up intervals. There were more deaths and the 1-, 5- and 7-year survival was lower in patients ≤10 years of age at HT. Early rejection was significantly higher in CHD patients exposed to homograft tissue, but not late rejection. Mortality/retransplantation rate was significantly higher and allograft survival lower in CHD hearts with excessive fibrosis of one or both ventricles. Anatomic diagnosis at pathologic examination differed from the clinical diagnosis in eight cases. CONCLUSIONS: Survival was better for the cardiomyopathy group and patients >10 years at HT. Prior homograft use was associated with a higher prevalence of early rejection. Ventricular fibrosis (of explant) was a strong predictor of outcome in the CHD group. We presented several pathologic findings in explanted pediatric hearts.

Comparative Effect of High-Frequency Nasal Cannula and Noninvasive Ventilation on the Work of Breathing and Postoperative Pulmonary Complication after Pediatric Congenital Cardiac Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: Various forms of commonly used noninvasive respiratory support strategies have considerable effect on diaphragmatic contractile function which can be evaluated using sonographic diaphragm activity parameters. OBJECTIVE: To compare the magnitude of respiratory workload decreased as assessed by thickening fraction of the diaphragm and longitudinal diaphragmatic strain while using high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) modes [nasal intermittent positive pressure ventilation (NIPPV) and bilevel positive airway pressure (BiPAP)] in pediatric patients after cardiothoracic surgery. METHODOLOGY: This prospective randomized controlled trial was performed at a tertiary care surgical intensive care unit in postcardiac surgery patients aged between 1 and 48 months, who were randomly allocated into three groups: 1) HFNC (with flows at 2 L/kg/min), 2) NIPPV via RAMS cannula in PSV mode (pressure support 8 cmH2O, PEEP 5 cmH2O), and 3) BiPAP in nCPAP mode (CPAP of 5 cmH2O). Measurements were recorded at baseline after extubation (R0) and subsequently every 12 hourly (R1, R2, R3, R4, R5) at 12, 24, 36, 48, and 60 hours respectively until therapy was discontinued. RESULTS: Sixty patients were included, with 20 patients each in the NIPPV group, HFNC group, and BiPAP group. Longitudinal strain at crura of diaphragm was lower in the BiPAP group as compared to HFNC group at R2-R4 [R2 (-4.27± -2.73 vs - 8.40± -6.40, P = 0.031), R3 (-5.32± -2.28 vs -8.44± -5.6, P = 0.015), and R4 (-3.8± -3.42 vs -12.4± -7.12, P = 0.040)]. PFR was higher in HFNC than NIPPV group at baseline and R1-R3[R0 (323 ± 114 vs 264 ± 80, P = 0.008), R1 (311 ± 114 vs 233 ± 66, P = 0.022), R2 (328 ± 116 vs 237 ± 4, P = 0.002), R3 (346 ± 112 vs 238 ± 54, P = 0.001)]. DTF and clinical parameters of increased work of breathing remain comparable between three groups. The rate of reintubation (within 48 hours of extubation or at ICU discharge) was 0.06% (1 in NIPPV, 1 in BiPAP, 2 in HFNC) and remain comparable between groups (P = 1.0). CONCLUSION: BiPAP may provide better decrease in work of breathing compared to HFNC as reflected by lower crural diaphragmatic strain pattern. HFNC may provide better oxygenation compared to NIPPV group, as reflected by higher PFR ratio. Failure rate and safety profile are similar among different methods used.

Quadricuspid Aortic Valve: Interesting Images.

ABSTRACT: The quadricuspid aortic valve is a rare congenital anomaly, usually associated with aortic regurgitation requiring surgical intervention. It may be associated with other congenital anomalies such as coronary anomalies, patent ductus arteriosus, ventricular septal defect, pulmonary stenosis, and subaortic stenosis. The diagnosis is generally established by either transthoracic or transesophageal echocardiography. Herein, we report a case of a 52-year-old woman who was diagnosed to have quadricuspid aortic valve by intraoperative transesophageal echocardiography.

Intracranial Pressure and Cerebral Hemodynamics in Infants Before and After Glenn Procedure.

OBJECTIVES: This prospective cohort study aimed to investigate changes in intracranial pressure (ICP) and cerebral hemodynamics in infants with congenital heart disease undergoing the Glenn procedure, focusing on the relationship between superior vena cava pressure and estimated ICP. DESIGN: A single-center prospective cohort study. SETTING: The study was conducted in a cardiac center over 4 years (2019-2022). PATIENTS: Twenty-seven infants with congenital heart disease scheduled for the Glenn procedure were included in the study, and detailed patient demographics and primary diagnoses were recorded. INTERVENTIONS: Transcranial Doppler (TCD) ultrasound examinations were performed at three time points: baseline (preoperatively), postoperative while ventilated (within 24-48 hr), and at discharge. TCD parameters, blood pressure, and pulmonary artery pressure were measured. MEASUREMENTS AND MAIN RESULTS: TCD parameters included systolic flow velocity, diastolic flow velocity (dFV), mean flow velocity (mFV), pulsatility index (PI), and resistance index. Estimated ICP and cerebral perfusion pressure (CPP) were calculated using established formulas. There was a significant postoperative increase in estimated ICP from 11 mm Hg (interquartile range [IQR], 10-16 mm Hg) to 15 mm Hg (IQR, 12-21 mm Hg) postoperatively (p = 0.002) with a trend toward higher CPP from 22 mm Hg (IQR, 14-30 mm Hg) to 28 mm Hg (IQR, 22-38 mm Hg) postoperatively (p = 0.1). TCD indices reflected alterations in cerebral hemodynamics, including decreased dFV and mFV and increased PI. Intracranial hemodynamics while on positive airway pressure and after extubation were similar. CONCLUSIONS: Glenn procedure substantially increases estimated ICP while showing a trend toward higher CPP. These findings underscore the intricate interaction between venous pressure and cerebral hemodynamics in infants undergoing the Glenn procedure. They also highlight the remarkable complexity of cerebrovascular autoregulation in maintaining stable brain perfusion under these circumstances.

A Case of Incidentally Discovered Congenital Complete Pericardial Defect during Lobectomy for Lung Cancer: A Case Report and Literature Review.

An 82-year-old male patient underwent a left upper lobectomy with anterolateral thoracotomy for lung cancer. Although a complete left-pericardial defect was observed during surgery, the pericardial repair was not performed because the left lower lobe remained and the heart was considered stable. Postoperative pathological examination revealed primary synchronous double-lung squamous-cell carcinoma (pathological stage pT2a(2)N0M0 stage IB). He was discharged without complications on postoperative day 8. Leftward displacement of the heart and left diaphragmatic elevation, suspected of phrenic-nerve paralysis, were found in the chest X-ray after discharge. However, the patient's overall condition remained unaffected at the 5-month postoperative follow-up. To assess the need for pericardial repair, we compared cases of complete pericardial defects observed during lobectomy or pneumonectomy reported in the literature. Only one of 12 cases occurred postoperative death despite pericardial repair, and that case combined pectus excavatum and pericardial defects. Our assessment indicated that pericardial repair might not be necessary, excluding complex cases.

[A survey on the implementation of cardiovascular surgery for congenital heart disease in China between 2017 and 2021].

Objective: To investigate the inplementation of cardiovascular surgery for congenital heart disease (CHD) in China. Methods: A cross-sectional study was carried out. The CHD cardiovascular surgery data collected by the Chinese Society of Extracorporeal Circulation from 2017 to 2021 in 31 provinces (autonomous regions/municipalities) of China were retrospectively reviewed, the implementation of CHD cardiovascular surgery in different provinces, regions, general/specialized hospitals, and different age groups (whether≤18 years old) were summarized, and the correlation analysis between the number of surgeries carried out in each province/region and the gross regional product and the number of the regional population was performed. Results: Between 2017 and 2021, the annual volume of CHD cardiovascular surgery was 77 120, 77 634, 81 161, 62 663 and 71 492, respectively, showing a decreasing trend. Meanwhile, the proportion of CHD patients aged≤18 years who underwent cardiovascular surgery also showed a downward trend, from 79.8% (61 557/77 120) in 2017 to 58.6% (41 871/71 492) in 2021 (P=0.027). The number of surgical cases varied greatly among different provinces, including 4 provinces with≥5 000 cases and 9 provinces with 2 000-5 000 cases. In the five years, the number of CHD cardiovascular surgeries in Central and East China was the largest, accounting for 41.1%-45.5% of the total surgical cases. The proportion of CHD surgery cases≤18 years old was the highest in Southwest China (69.7%-87.4%) and the lowest in Northeast China (28.2%-68.9%). Except for 2021, the number of cases carried out by each region between 2017 and 2020 was correlated with the gross regional product (r=0.929, 0.929, 0.893 and 0.964, respectively, all P<0.05) and the population (r=0.821, 0.893, 0.821 and 0.857, respectively, all P<0.05). Hospitals that performed more than 100 operations (20.5%±1.2% of the total number of hospitals) completed 86.2%±1.2% of the total number of operations in China during the 5-year period. In 2017 and 2021, the number of CHD cardiovascular surgeries preformed in children's/women's and children's specialized hospitals accounted for 24.3% (18 772/77 120) and 23.8% (17 012/71 492) of the total number of cases in China, respectively. Conclusions: From 2017 to 2021, the number of cardiovascular surgery for CHD decreases slightly, but the proportion of surgery for adult CHD patients increases significantly.There is a strong correlation between the number of CHD operations in each region and their economic development status. The scale of CHD cardiovascular surgery performed in children's hospitals/women's and children's hospitals accounts for about a quarter of the total volume in China.

Challenges of Congenital Heart Surgery in Brazil: It is Time to Designate Pediatric Congenital Heart Surgery Subspecialty.

Congenital heart disease (CHD) affects eight to ten out of every 1,000 births, resulting in approximately 23,057 new cases in Brazil in 2022. About one in four children with CHD requires surgery or other procedures in the first year of life, and it is expected that approximately 81% of these children with CHD will survive until at least 35 years of age. Professionals choosing to specialize in CHD surgery face numerous challenges, not only related to mastering surgical techniques and the complexity of the diseases but also to the lack of recognition by medical societies as a separate subspecialty. Furthermore, families face difficulties when access to services capable of providing treatment for these children. To address these challenges, it is essential to have specialized hospitals, qualified professionals, updated technologies, sustainable industry, appropriate financing, quality assessment systems, and knowledge generation. The path to excellence involves specialization across all involved parties. As we reflect on the importance of Pediatric Cardiovascular Surgery and Congenital Heart Diseases establishing themselves as a subspecialty of Cardiovascular Surgery, it is essential to look beyond our borders to countries like the United States of America and United Kingdom, where this evolution is already a reality. This autonomy has led to significant advancements in research, education, and patient care outcomes, establishing a care model. By following this path in Brazil, we not only align our practice with the highest international standards but also demonstrate our maturity and the ability to meet the specific needs of patients with CHD and those with acquired childhood heart disease.

Comparative Analysis of Modified BT Shunt and Central Shunt in Pediatric Patients.

INTRODUCTION: Cyanotic congenital heart diseases constitute 40-45% of all congenital heart diseases. In patients who are not suitable for primary repair, modified BT (MBT) shunt and central shunt (CS) procedures are still frequently used. METHODS: This study included 62 pediatric patients who underwent MBT shunt or CS via median sternotomy. Patients' demographic, echocardiographic, operative, and postoperative data were collected retrospectively. The patients were classified as single ventricle and bi-ventricle according to their cardiac anatomy, and the presence of prematurity and heterotaxy was noted. Procedure details of the patients who underwent endovascular intervention prior to the surgery were investigated, and operation data were accessed from the surgery notes. Data regarding postoperative follow-ups were obtained and comparatively analyzed. RESULTS: Of the total 62 patients, 32 (51.6%) were newborns and 16 (25.8%) had a body weight < 3 kg. MBT shunt was applied to 48 patients (77.4%), while CS was applied to 14 patients (22.6%). There was no significant difference between the two surgical procedures in terms of requirement for urgent shunt or cardiopulmonary bypass, additional simultaneous surgical intervention, need for high postoperative inotropes, and in-hospital mortality (P>0.05). The rate of congestive heart failure in patients with in-hospital mortality was determined as 66.7% and it was significantly higher than in patients without heart failure (P<0.001). CONCLUSION: MBT shunt and CS are still frequently used in cyanotic patients. The use of small-diameter shunts, particularly when centrally located, can prevent the onset of congestive heart failure and lower mortality.

Prediction of Vasoactive-Inotropic Score on Prolonged Mechanical Ventilation in Adult Congenital Heart Disease Patients After Surgical Treatment Combined with Coronary Artery Bypass Grafting.

INTRODUCTION: This study aimed to investigate the predictive value of the vasoactive-inotropic score (VIS) at different time points for postoperative prolonged mechanical ventilation (PMV) in adult congenital heart disease patients undergoing surgical treatment combined with coronary artery bypass grafting. METHODS: Patients were divided into two groups that developed PMV or not. The propensity score matching method was applied to reduce the effects of confounding factors between the two groups. VIS at different time points (VIS at the end of surgery, VIS6h, VIS12h, and VIS12h max) after surgery were recorded and calculated. The value of VIS in predicting PMV was analyzed by the receiver operating characteristic (ROC) curve, and multivariate logistic regression was used to analyze independent risk factors. RESULTS: Among 250 patients, 52 were in the PMV group, and 198 were in the non-PMV group. PMV rate was 20.8%. After propensity score matching, 94 patients were matched in pairs. At each time point, the area under the ROC curve predicted by VIS for PMV was > 0.500, among which VIS at the end of surgery was the largest (0.805). The optimal cutoff point for VIS of 6.5 could predict PMV with 78.7% sensitivity and 72.3% specificity. VIS at the end of surgery was an independent risk factor for PMV (odds ratio=1.301, 95% confidence interval 1.091~1.551, P<0.01). CONCLUSION: VIS at the end of surgery is an independent predictor for PMV in patients with adult congenital heart disease surgical treatment combined with coronary artery bypass grafting.

Prevalence and Risk Factors for Cerebral Palsy in Children With Congenital Heart Disease Based on Risk of Surgical Mortality.

BACKGROUND: Children with congenital heart disease (CHD) have a higher prevalence of motor impairment secondary to brain injury, resulting in cerebral palsy (CP). The purpose of this study is to determine the prevalence of CP in CHD in a single-center cohort, stratify risk based on surgical mortality using Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) categories and identify risk factors. METHODS: Retrospective cohort study of pediatric patients registered in the University of Florida (UF) Society of Thoracic Surgeons Congenital Heart Surgery database from 2006 to 2017 with a diagnosis of CHD who continued follow-up for more than two years at UF. RESULTS: A total of 701 children with CHD met inclusion criteria. Children identified to have CP were 54 (7.7%). Most common presentation was spastic hemiplegic CP with a Gross Motor Function Classification System of level 2. Analysis of surgical and intensive care factors between the two groups showed that children with CHD and CP had longer time from admission to surgery (P = 0.003), higher STAT categories 4 and 5 (P = 0.038), and higher frequency of brain injury and seizures (P < 0.001). Developmental disabilities and rehabilitation needs were significantly greater for children with CHD and CP when compared with those with CHD alone (P < 0.001). CONCLUSIONS: In our cohort, 7.7% children with CHD develop CP; this is significantly higher than the 2010 US population estimate of 0.3%. Our study suggests higher STAT categories, brain injury, and seizures are associated with developing CP in children with CHD.

Mortality and morbidity after combined heart and liver transplantation in the failing Fontan: An updated dual center retrospective study.

INTRODUCTION: As the adult Fontan population with Fontan associated liver disease continues to increase, more patients are being referred for transplantation, including combined heart and liver transplantation. METHODS: We report updated mortality and morbidity outcomes after combined heart and liver transplant in a retrospective cohort series of 40 patients (age 14 to 49 years) with Fontan circulation across two centers from 2006-2022. RESULTS: The 30-day, 1-year, 5-year and 10-year survival rate was 90%, 80%, 73% and 73% respectively. Sixty percent of patients met a composite comorbidity of needing either post-transplant mechanical circulatory support, renal replacement therapy or tracheostomy. Cardiopulmonary bypass time > 283 min (4.7 h) and meeting the composite comorbidity were associated with mortality by Kaplan Meier analysis. CONCLUSION: Further study to mitigate early mortality and the above comorbidities as well as the high risk of bleeding and vasoplegia in this patient population is warranted.

Epidemiology of congenital heart defects in France from 2013 to 2022 using the PMSI-MCO (French Medical Information System Program in Medicine, Surgery, and Obstetrics) database.

BACKGROUND: Congenital heart defects are common and occur in approximately 0.9% of births. In France, the registries cover approximately 20% of the population but not the entirety of France; therefore, we aimed to update the incidence data for congenital heart defects in France from 2013 to 2022 using the medico-administrative database PMSI-MCO (French Medical Information System Program in Medicine, Surgery, and Obstetrics). We aimed to compare the frequency of risk factors in a population with congenital heart defects and a reference population. METHODS: From 2013 to 2022, we included children aged < 3 years diagnosed with congenital heart defects according to the International Classification of Diseases, 10th Revision, in the PMSI-MCO database. We compared them with a population without congenital defects on several medical data items (e.g., parity, gemellarity, and mortality rate). Bivariate and multivariate analyses compared children with congenital heart defects and children without congenital malformation. RESULTS: We identified 83,879 children with congenital heart defects in France from 2013 to 2022 in the PMSI-MCO database and 7,739,840 children without such defects, including 7,218,952 without any congenital defects. We observed more deaths (7.49% vs. 0.68%, d = 0.59) and more twinning (8.67% vs. 1.23%, d = 0.35) among children with congenital heart defects. Multivariate analysis revealed an increased risk of congenital heart defects in male individuals (OR [odds ratio] 1.056, 95% CI [confidence interval] [1.039-1.076]) and cases of medically assisted reproduction (OR 1.115, 95% CI [1.045-1.189]) and a reduced risk in the case of multiparity (OR 0.921, 95% CI [0.905-0.938]). CONCLUSIONS: According to the PMSI-MCO database, the incidence of congenital heart defects in France from 2013 to 2022 is 1% of births. Congenital heart defects are more frequent in cases of prematurity, twinning, primiparity, male sex, and maternal age > 40 years.

Clinical features of plastic bronchitis in children after congenital heart surgery.

BACKGROUND: Plastic bronchitis (PB) can occur in patients who have undergone congenital heart surgery (CHS). This study aimed to investigate the clinical features of PB in children after CHS. METHODS: We conducted a retrospective cohort study using the electronic medical record system. The study population consisted of children diagnosed with PB after bronchoscopy in the cardiac intensive care unit after CHS from May 2016 to October 2021. RESULTS: A total of 68 children after CHS were finally included in the study (32 in the airway abnormalities group and 36 in the right ventricular dysfunction group). All children were examined and treated with fiberoptic bronchoscopy. Pathogens were detected in the bronchoalveolar lavage fluid of 41 children, including 32 cases in the airway abnormalities group and 9 cases in the right ventricular dysfunction group. All patients were treated with antibiotics, corticosteroids (intravenous or oral), and budesonide inhalation suspension. Children with right ventricular dysfunction underwent pharmacological treatment such as reducing pulmonary arterial pressure. Clinical symptoms improved in 64 children, two of whom were treated with veno-arterial extracorporeal membrane oxygenation (ECMO) due to recurrent PB and disease progression. CONCLUSIONS: Children with airway abnormalities or right ventricular dysfunction after CHS should be alerted to the development of PB. Pharmacological treatment such as anti-infection, corticosteroids, or improvement of right ventricular function is the basis of PB treatment, while fiberoptic bronchoscopy is an essential tool for the diagnosis and treatment of PB. ECMO assistance is a vital salvage treatment for recurrent critically ill PB patients.

Double trouble - dual outflow tract obstruction in congenital heart disease: a case report.

BACKGROUND: Double chambered right ventricle is a rare congenital heart disease that is characterised by the presence of an anomalous muscle bundle that divides the right ventricle into a low pressure superior (distal) chamber and a high pressure inferior (proximal) chamber. It is found in association with a ventricular septal defect in 90% cases with other associations being tetralogy of Fallot, transposition of great vessels, atrial septal defect and Ebstein's anomaly. On the other hand, subaortic membrane is a form of discrete subaortic stenosis that is characterised by a membranous diaphragm in the subvalvular location of the left ventricular outflow tract. Both of these entities are responsible for causing subvalvular outflow tract obstruction. The occurrence of double chambered right ventricle in association with subaortic membrane is an extremely rare entity with only a few case reports available in the literature. CASE REPORT: A 13-year-old male child with history of chest pain and palpitations presented to the outpatient department of a tertiary care center. Transthoracic echocardiography revealed a subaortic membrane producing a pressure gradient across the left ventricular outflow tract with dilatation of the right atrium and right ventricle which could not be fully evaluated on echocardiography. Cardiac computed tomography was then performed which additionally revealed an anomalous muscle bundle coursing across the right ventricle from the septum to the subinfundibular region creating a double chambered right ventricle. The patient was then taken up for reconstruction of right ventricular outflow tract and resection of subaortic membrane. CONCLUSION: Right and left outflow tract obstructions are rare congenital lesions which when seen in combination, become even more infrequent. Echocardiography is a robust tool that detects turbulent flow to identify such lesions. However, poor acoustic window may sometimes result in missing these lesions and computed tomography in such situations can play an important role in detection as well as complete preoperative imaging evaluation.

The Year in Review: Anesthesia for Congenital Heart Disease 2023.

This review highlights published literature in 2023 that is related to the anesthetic management of patients with congenital heart disease (CHD). Though not inclusive of all topics, 31 articles are discussed and four primary themes emerged: transfusion and hemostasis, outcomes and risk assessment, monitoring, and pharmacology.

Quadricuspid Aortic Valve: Imaging, Diagnosis, and Prognosis.

Quadricuspid aortic valve is a rare congenital cardiac anomaly with an incidence of 0.008% to 0.043%. Its clinical course varies depending on cusp anatomy, function, and associated cardiac malformations. It frequently progresses to aortic valve regurgitation that may require surgical valve replacement. Detection has shifted from incidental discovery during autopsies or cardiac surgeries in the early 20th century to various cardiac imaging methods in recent decades. In addition to contributing to the literature, this report supports the use of transesophageal echocardiography more liberally to detect aortic valve abnormalities. The case presents a 48-year-old female patient with an incidentally discovered quadricuspid aortic valve.

Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation.

BACKGROUND: The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling. METHODS: SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. RESULTS: SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased. CONCLUSIONS: Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.