Patients with interrupted inferior vena cava (I-IVC) and azygos continuation who undergo Fontan completion via hepatoazygos shunting exhibit unique hemodynamic challenges. This study evaluates age-related shifts in systemic venous return dominance, hepatic flow distribution (HFD), power loss (PL), and flow disturbances using patient-specific computational fluid dynamics (CFD). Data analysis from 95 patients with I-IVC showed a nonlinear shift in upper-to-lower body systemic flow dominance with ratios of 2, 1, and 0.5 (correlating to ages ∼3, ∼10, and ∼20, respectively). CFD simulations for 17 selected patients revealed a trend of increasing HFD toward the right pulmonary artery, with median splits of 45%-49%, 48%-52%, and 40%-60% for the respective flow ratios. Power loss increased significantly with lower-body flow dominance. Median values for absolute PL were 4.75 mW (ratio 2), 16.5 mW (ratio 1), and 33.7 mW (ratio 0.5). Indexed PL showed a similar trend, rising from 0.04 mW/m2 to 0.11 mW/m2 across the flow ratios. Vorticity and viscous dissipation rates, key metrics of flow disturbances, also increased with lower-body flow dominance, showing strong correlations with PL (R = 0.58-0.76). Kruskal-Wallis-based statistical analysis identified significant statistical differences in absolute PL (P = 0.0045) and flow disturbances (P < 0.001), emphasizing the impact of age-related flow dynamics on Fontan efficiency. Our findings emphasize the need for targeted interventions in patients with I-IVC with azygos continuation to mitigate evolving hemodynamic inefficiencies and optimize Fontan outcomes during critical growth periods.NEW & NOTEWORTHY Evaluate how age-driven changes in patients with interrupted inferior vena cava impact Fontan efficiency. Using patient-specific computational fluid dynamics, our study reveals nonlinear flow dynamics, increasing power loss, and evolving hepatic flow distribution, emphasizing the need for tailored interventions to optimize outcomes.

Background: Patients with hypoplastic left ventricles (LV) who undergo volume-loading procedures (recruitment, biventricular [BIV] repair) are at risk for adverse outcomes, including heart failure and death. We investigated pre-BIV LV shape as a predictor of outcome after BIV repair in patients with hypoplastic LVs. Methods: Baseline and post-recruitment cardiac magnetic resonance imaging and computed tomography data were analyzed in patients with hypoplastic LV (<50 mL/m(2)). Statistical shape modeling (SSM) was utilized to generate a model of the shape and variability of LVs. Traditional measures of LV sphericity and eccentricity were also measured. Major adverse cardiovascular events (MACE) included heart failure, transplant, and death. Results: Of 95 patients with baseline mean LV volume 29 +/- 13 mL/m(2), 45/95 (47%) had a right dominant atrioventricular canal defect, 31/95 (33%) had a variant of hypoplastic left heart syndrome, and 18/95 (19%) had endocardial fibroelastosis (EFE). A wide variation in LV shape was found by SSM, and shape modes were associated with right ventricle (RV) and LV size, and diagnosis. BIV repair was achieved in 74/95 (78%) patients; 13/74 (18%) of BIV patients had MACE. Predictors of MACE following BIV repair included EFE, higher RV mass index, and higher RV end-diastolic volume index. No baseline or post-recruitment LV shape parameter was associated with the outcome after BIV repair. Conclusion: The shape model of hypoplastic LVs demonstrated a wide array of LV shapes. LVs gained sphericity and size and lost eccentricity with recruitment. Though the ventricles changed shape with recruitment, no specific LV shape characteristic at the baseline or post-recruitment stage was predictive of decision to proceed with BIV repair or outcome. Higher RV mass and volume may represent new biomarkers that predict outcomes following BIV repair in patients with hypoplastic LV. Further investigation could determine the reproducibility of these findings.

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 (EC) conduit or a lateral tunnel (LT) 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. Objective:The effect of age-related changes in caval inflows on HFD was evaluated using cardiac MRI (CMR) data and patient-specific computational fluid dynamics (CFD) modeling. Methods:SVC and IVC flow from 414 Fontan patients were collected to establish a relationship between SVC:IVC flow ratio and age. CFD modeling was performed in 60 (30 EC and 30 LT) 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 EC but statistically significant for LT cohorts. For all three 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→0.5 (age 3→15+), the correlation's strength decreased from 0.87→0.64, due to potential flow perturbation as IVC flow momentum increased. Conclusion:Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of including SVC:IVC variations over time to understand Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes. Clinical Perspective:With improvement in standard of care and management of single ventricle patients with Fontan physiology, the population of adults with Fontan circulation is increasing. Consequently, there is a clinical need to comprehend the impact of patient growth on Fontan hemodynamics. Using CMR data, we were able to quantify the relationship between changing caval inflows and somatic growth. We then used patient-specific computational flow modeling to quantify how this relationship affected the distribution of long-term hepatic flow in extracardiac and lateral tunnel Fontan types. Our findings demonstrated the significance of including SVC:IVC changes over time in CFD modeling to learn more about the long-term hemodynamics of Fontan. Fontan surgical approaches are increasingly planned and optimized using computational flow modeling. For a patient undergoing a Fontan procedure, the workflow presented in this study that takes into account the variations in Caval inflows over time can aid in predicting the long-term hemodynamics in a planned Fontan pathway.

BackgroundSingle ventricle (SV) patients with interrupted inferior vena cava (iIVC) and azygos continuation are at high risk for unbalanced hepatic venous flow (HVF) distribution to the lungs after Fontan completion and subsequent pulmonary arteriovenous malformations (AVMs) formation.ObjectivesThe aim of the study was to utilize computational fluid dynamics (CFD) analysis to avoid maldistribution of HVF to the lungs after Fontan surgery.MethodsFour SV subjects with iIVC were prospectively studied with a 3-dimensional (3D) modeling workflow with digital 3D models created from segmented magnetic resonance images or computer tomography scans, virtual surgery, and CFD analysis over multiple physiologic states for the evaluation of operative plans to achieve balanced HVF to both lungs. Three of the patients were Fontan revision candidates with existing AVMs. All patients underwent Fontan completion or revision surgery.ResultsCFD predicted that existing or proposed Fontan completion in all patients would result in 100% of HVF to one lung. Improved HVF balance was achieved with CFD analysis of alternative surgical approaches resulting in the average distribution of HVF to the right/left pulmonary arteries of 37%/63% ± 10.4%. A hepatoazygos shunt was required in all patients and additional creation of an innominate vein in one. CFD analysis was validated by the comparison of pre-operative predicted and postoperative MRI-measured total right/left pulmonary flow (51%/49% ± 5.4% vs 49%/51% ± 8.5%).ConclusionsA 3D modeling workflow with CFD simulation for SV patients with iIVC may avoid HVF maldistribution and development of AVMs after Fontan completion.

The hemodynamics in Fontan patients with single ventricles rely on favorable flow and energetics, especially in the absence of a subpulmonary ventricle. Age-related changes in energetics for extracardiac and lateral tunnel Fontan procedures are not well understood. Vorticity (VOR) and viscous dissipation rate (VDR) are two descriptors that can provide insights into flow dynamics and dissipative areas in Fontan pathways, potentially contributing to power loss. This study examined power loss and its correlation with spatio-temporal flow descriptors (vorticity and VDR). Data from 414 Fontan patients were used to establish a relationship between the superior vena cava (SVC) to inferior vena cava (IVC) flow ratio and age. Computational flow modeling was conducted for both extracardiac conduits (ECC, n = 16) and lateral tunnels (LT, n = 25) at different caval inflow ratios of 2, 1, and 0.5 that corresponded with ages 3, 8, and 15+. In both cohorts, vorticity and VDR correlated well with PL, but ECC cohort exhibited a slightly stronger correlation for PL-VOR (>0.83) and PL-VDR (>0.89) than that for LT cohort (>0.76 and > 0.77, respectively) at all ages. Our data also suggested that absolute and indexed PL increase (p < 0.02) non-linearly as caval inflow changes with age and are highly patient-specific. Comparison of indexed power loss between our ECC and LT cohort showed that while ECC had a slightly higher median PL for all 3 caval inflow ratio examined (3.3, 8.3, 15.3) as opposed to (2.7, 7.6, 14.8), these differences were statistically non-significant. Lastly, there was a consistent rise in pressure gradient across the TCPC with age-related increase in IVC flows for both ECC and LT Fontan patient cohort. Our study provided hemodynamic insights into Fontan energetics and how they are impacted by age-dependent change in caval inflow. This workflow may help assess the long-term sustainability of the Fontan circulation and inform the design of more efficient Fontan conduits.

Pulmonary valve (PV) monocusp reconstruction in transannular patch (TAP) right ventricular outflow tract (RVOT) repair for Tetralogy of Fallot has variable clinical outcomes across different surgical approaches. The study purpose was to systematically evaluate how monocusp leaflet design parameters affect valve function in-vitro. A 3D-printed, disease-specific RVOT model was tested under three infant physiological conditions. Monocusps were sewn into models with the native main pulmonary artery (MPA) forming backwalls that constituted 40

ObjectivePostoperative heart block is a significant problem in congenital heart surgery because of the unpredictability and variability of conduction tissue location in complex congenital heart defects. A novel technique for intraoperative conduction system mapping during complex congenital heart surgery is described.MethodsIntraoperative conduction system mapping was performed utilizing a high-density multielectrode grid catheter to collect intracardiac electrograms on open, beating hearts during repair of complex congenital heart defects. Electrograms were interpreted by electrophysiologists, and conduction tissue location was communicated in real time to the surgeon. After localizing conduction tissue, the heart was arrested and the repair was completed taking care to avoid injury to the mapped conduction system.ResultsTwo patients with complex heterotaxy syndrome underwent intraoperative conduction mapping during biventricular repair. Mapping accurately identified the location of conduction tissue thereby enabling avoidance of conduction system injury during surgery. Notably, conduction was unexpectedly found to be located inferiorly in a patient with L-looped ventricles. Successful biventricular repair was accomplished in both patients without injury to the conduction system.ConclusionsIntraoperative conduction mapping can effectively localize the conduction system during surgery and enable the surgeon to avoid its injury. This can lower the risk of heart block requiring pacemaker in children undergoing complex congenital heart surgery.

Introduction: The Fontan procedure is performed between 2-4 years of age and is a palliative technique for patients born with single ventricle defects. The Fontan physiology is the result of a total cavopulmonary connection between superior and inferior vena cava (SVC and IVC) and the hepatic veins to the pulmonary arteries (PA). Maldistribution of hepatic blood flow to the lungs can result in the formation of pulmonary arteriovenous malformations (PAVM) and resulting cyanosis. Hepatic blood flow distribution (HFD) to right and left lungs is highly dependent on the local flow dynamics. We sought to investigate the impact of SVC-to-IVC flow ratio and age on HFD. Methods: SVC and IVC flow data measured by cardiac MRI (CMR) from 81 Fontan patients were collected to establish the relationship between SVC: IVC flow ratio vs. age. 3D Patient-specific computational fluid dynamics (CFD) modeling was performed for 5 patients who underwent Fontan procedure with an extracardiac conduit to quantify the HFD to the right and left PAs. We evaluated the dependency of HFD on SVC: IVC flow ratio by quantifying HFD to different SVC: IVC flow ratios (2, 1.0, and 0.5) for a given Fontan anatomy. Results: SVC: IVC flow ratio inverted at ~10 years of age (n=81, Figure A) indicating a clear shift to lower body predominance in overall caval flow. CFD analysis (n=5) showed that the shift in SVC-IVC flow had a significant effect on the HFD (Fig. B-F). Change in HFD was more substantial as SVC: IVC flow ratio shifted from 2 to 1 [~5-10 years] with an average % change of 21±6 compared to the HFD change that occurred for a shift of 1 to 0.5 [9±11 for ~10-20 years] (Fig. B-F). Conclusion: Well-balanced distribution of HFD is essential to prevent PAVMs and to ensure long-term efficacy of a Fontan. This study highlights how SVC: IVC flow ratios change over time and can impact HFD to PAs. Interventions to address HFD maldistribution should not be considered in isolation and should incorporate predictions of SVC: IVC changes over time.

Purpose Tetralogy of Fallot and other conditions affecting the right ventricular outflow tract (RVOT) are common in pediatric patients, but there is a lack of quantitative comparison among techniques for repairing or replacing the pulmonary valve. The aim of this study was to develop a robust in vitro system for quantifying flow conditions after various RVOT interventions.Methods An infant-sized mock circulatory loop that includes a 3D-printed RVOT anatomical model was developed to evaluate flow conditions after different simulated surgical repairs. Physiologically correct flow and pressure were achieved with custom compliant tubing and a tunable flow restrictor. Pressure gradient, flow regurgitation, and coaptation height were measured for two monocusp leaflet designs after tuning the system with a 12 mm Hancock valved conduit.Results Measurements were repeatable across multiple samples of two different monocusp designs, with the wider leaflet in the 50% backwall model consistently exhibiting lower pressure gradient but higher regurgitation compared to the leaflet in the 40% backwall model. Coaptation height was measured via direct visualization with endoscopic cameras, revealing a shorter area of contact for the wider leaflet (3.3-4.0 mm) compared to the narrower one (4.3 mm).Conclusion The 3D-printed RVOT anatomical model and in vitro pulmonary circulatory loop developed in this work provide a platform for planning and evaluating surgical interventions in the pediatric population. Measurements of regurgitation, pressure gradient, and coaptation provide a quantitative basis for comparison among different valve designs and positions.

Heterotaxy (HTX) syndrome is associated with complex congenital heart disease (CCHD) and AV node (AVN) anomalies. Superior or inferior AVN displacement has been believed to be dictated by ventricular looping. Biventricular (BiV) repair of CCHD in HTX requires extensive AV valve and outflow tract surgery, jeopardizing the AVN, and has been associated with rates of AV block (AVB) of 15-25%.

Blalock-Taussig (BT) Shunt is a palliative surgical procedure used during a Norwood surgery on a newborn baby suffering from cyanotic heart defects. The BT Shunt can increase blood flow in patients’ pulmonary artery which can ease the “Blue Baby Syndrome.” Currently used BT Shunts do not produce a balanced flow distribution to the pulmonary arteries (PAs) which can cause high wall shear stress (WSS) and blood flow separation resulting in blood clots. A modified BT Shunt was designed to partially solve this problem. In our previous work [1], the modified BT Shunt was shown by numerical simulations to have the ability to better control the flow distribution between Innominate Artery (IA) and PA with lower and gradually varying WSS and with improved flow balance to the pulmonary artery at the T-junction of the shunt. The goal of this paper is to computationally evaluate the flow in the modified BT shunt model between innominate and pulmonary artery using a patient specific aorta model. The simulations are performed using the commercial CFD software ANSYS Fluent. The improved modified BT shunt is connected between IA and PA. A change in the length of the shunt can be made to fit it under different conditions of actual patients. In numerical simulations, a full geometry of patient’s aorta is considered. Results for different lengths of the shunt are compared to determine the length that generates the lowest WSS and improved flow distribution to the PAs. It was found that the length of nearly 26mm creates lower WSS and flow rate difference between the two sides of PA at the T-junction attachment of the shunt. A sophisticated computational model was created using SolidWorks and Blender software to create the realistic geometry which included the IA, PA and modified BT shunt. The numerical simulations provide details of the flow field including velocity and pressure field, WSS, and blood damage. Several parameters in shunt design weigh heavily in reducing the thrombosis. This study demonstrates how CFD can be effectively utilized in the design of a medical device such as BT shunt to improve the clinical outcomes in patients.

Summary:. B.Y. was born full term after a large vertex encephalocele was diagnosed prenatally. The unique challenge to repairing B.Y.’s encephalocele was a microcephalic skull and large proportion of likely functional extracranial brain tissue, which would need to be preserved. At Boston Children’s Hospital, a simulation-based collaborative presurgical planning and rehearsal process, using both digital and 3D printed models, enabled successful technical completion and outcome of an otherwise inoperable case.

In the original article, an author name was incorrectly spelled as "Sanjay P. Prahbu." However, the correct spelling is "Sanjay P. Prabhu." The publisher regrets any inconvenience caused by this error. Creation and Validation of a Simulator for Neonatal Brain Ultrasonography: A Pilot StudyAcademic RadiologyVol. 24Issue 1PreviewHistorically, skills training in performing brain ultrasonography has been limited to hours of scanning infants for lack of adequate synthetic models or alternatives. The aim of this study was to create a simulator and determine its utility as an educational tool in teaching the skills that can be used in performing brain ultrasonography on infants. Full-Text PDF

Rationale and Objectives: Historically, skills training in performing brain ultrasonography has been limited to hours of scanning infants for lack of adequate synthetic models or alternatives. The aim of this study was to create a simulator and determine its utility as an educational tool in teaching the skills that can be used in performing brain ultrasonography on infants. Materials and Methods: A brain ultrasonography simulator was created using a combination of multi-modality imaging, threedimensional printing, material and acoustic engineering, and sculpting and molding. Radiology residents participated prior to their pediatric rotation. The study included (1) an initial questionnaire and resident creation of three coronal images using the simulator; (2) brain ultrasonography lecture; (3) hands-on simulator practice; and (4) a follow-up questionnaire and re-creation of the same three corona! images on the simulator. A blinded radiologist scored the quality of the pre-and post-training images using metrics including symmetry of the images and inclusion of predetermined landmarks. Wilcoxon rank-sum test was used to compare pre-and post-training questionnaire rankings and image quality scores. Results: Ten residents participated in the study. Analysis of pre-and post-training rankings showed improvements in technical knowledge and confidence, and reduction in anxiety in performing brain ultrasonography. Objective measures of image quality likewise improved. Mean reported value score for simulator training was high across participants who reported perceived improvements in scanning skills and enjoyment from simulator use, with interest in additional practice on the simulator and recommendations for its use. Conclusions: This pilot study supports the use of a simulator in teaching radiology residents the skills that can be used to perform brain ultrasonography.

This report documents the acoustic measurements that supplemented the September 2013 National Aeronautics and Space Administration (NASA) Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) flight tests in Houston, Texas and the corresponding data set developed from those measurements. These data include aircraft performance and position, meteorological and acoustic data of various aircraft events flown by two test aircraft at a range of altitudes. These data are supplemented by aircraft source data, measurement site location data, observations, and onboard acoustic data. The intended use of this data set is to validate the accuracy of aircraft acoustic modeling methods.