Clinical and 2D/3D-Echo Cardiography Determinants of Mitral Valve Reoperation in Children With Congenital Mitral Valve Disease.

Background: Congenital mitral valve disease (CMVD) presents major challenges in its medical and surgical management. Objectives: The purpose of this study was to investigate the value of 3-dimensional echocardiography (3DE) and identify associations with MV reoperation in this setting. Methods: All children <18 years of age who underwent MV reconstruction for CMVD in 2002 to 2018 were included. Preoperative and postoperative 2-dimensional echocardiography (2DE) and 3DE data were collected. Competing risks and Cox regression analysis were used to identify independent associations with MV reoperation. Receiver operating characteristic and decision-tree analysis were implemented for comparison of 3DE vs 2DE. Results: A total of 206 children underwent MV reconstruction for CMVD (mitral stenosis, n = 105, mitral regurgitation [MR], n = 75; mixed disease, n = 26); 64 (31%) required MV reoperation. Variables independently associated with MV reoperation were age <1 year (HR: 2.65; 95% CI: 1.13-6.21), tethered leaflets (HR: 2.00; 95% CI: 1.05-3.82), ≥ moderate 2DE postoperative MR (HR: 4.26; 95% CI: 2.45-7.40), changes in 3D-effective orifice area (3D-EOA) and in 3D-vena contracta regurgitant area (3D-VCRA). Changes in 3D-EOA and 3D-VCRA were more strongly associated with MV reoperation than changes in mean gradients (area under the curve [AUC]: 0.847 vs AUC: 0.676, P = 0.006) and 2D-VCRA (AUC: 0.969 vs AUC: 0.720, P = 0.012), respectively. Decision-tree analysis found that a <30% increase in 3D-EOA had 80% accuracy (HR = 8.50; 95% CI: 2.9-25.1) and a <40% decrease in 3D-VCRA had 93% accuracy (HR: 22.50; 95% CI: 2.9-175) in discriminating MV reoperation for stenotic and regurgitant MV, respectively. Conclusions: Age <1 year, tethered leaflets, 2DE postoperative MR, changes in 3D-EOA and 3D-VCRA were all independently associated with MV reoperation. 3DE parameters showed a stronger association than 2DE. 3DE-based decision-tree algorithms may help prognostication and serve as a support tool for clinical decision-making.

Experience Curve With the Cone Procedure for Ebstein's Anomaly: Effect on Cost and Resource Utilization.

Background: The volume-outcome relationship is well-known in health care. The Experience Curve, initially developed by the Boston Consulting Group for manufacturing, offers insight on this relationship and has never before been applied to health care. Objectives: The purpose of this study was to determine the effect of experience on cost and resource utilization for the Cone procedure. Methods: We performed a retrospective review of patients who underwent Cone reconstruction for Ebstein's anomaly at Boston Children's Hospital between October 2010 and October 2021. Cardiopulmonary bypass time and aortic cross clamp time over time were evaluated using exponential regression to assess the surgeon-level learning curve. At the hospital level, length of stay and cost over time were assessed using exponential regression. Results: There were 115 patients included in the study. Median hospital length of stay was 7.9 days (IQR: 6.4-10.2 days) with a decline of 3.3% per year. Median intensive care unit [ICU] length of stay was 3.2 days (IQR: 2-5.7 days) with a decline of 10.5% per year. Adjusted direct costs indexed to 2020 prices fell by 4% per year. There was no statistically significant change in cardiopulmonary bypass or aortic cross clamp time. In mediation analysis, the reduction in cost was completely accounted for in the decline in ICU length of stay. ICU length of stay was correlated with duration of intubation. Conclusions: Increasing familiarity with Ebstein's anomaly and Cone reconstruction led to a reduction in resource utilization.

Predictive modeling of endocardial fibroelastosis recurrence in patients with congenital heart disease.

BACKGROUND: Endocardial fibroelastosis (EFE) is a major effector in the maldevelopment of the heart in patients with congenital heart disease. Despite successful surgical removal, EFE can redevelop, but the underlying cause of EFE recurrence remains unknown. This study aimed to identify hemodynamic predictors and genetic links to epithelial/endothelial-to-mesenchymal transition (EMT/EndMT) alterations for preoperative risk assessment. METHODS: We assessed the impact of preoperative hemodynamic parameters on EFE recurrence in a cohort of 92 patients with congenital heart disease who underwent left ventricular (LV) EFE resection between January 2010 and March 2021. Additionally, whole-exome sequencing in 18 patients was used to identify rare variants (minor allele frequency <10-5) in high-expression heart (HHE) genes related to cardiac EMT/EndMT and congenital heart disease. RESULTS: EFE recurred in 55.4% of patients, within a median of 2.2 years postsurgery. Multivariable analysis revealed specific hemodynamic parameters (mitral valve inflow and area, LV filling pressure, and aortic valve gradient and diameter) as predictors, forming a predictive model with an area under the receiver operating characteristic curve of 0.782. Furthermore, 89% of the patients exhibited damaging variants in HHE genes, with 38% linked to cardiac EMT/EndMT Gene Ontology processes and 22% associated with known congenital heart disease genes. Notably, HHE genes associated with cardiac EMT/EndMT were significantly associated with faster EFE recurrence in a multivariate analysis (hazard ratio, 3.56; 95% confidence interval, 1.24-10.17; P = .018). CONCLUSIONS: These findings established a predictive scoring system using preoperative hemodynamic parameters for EFE recurrence risk assessment. Alterations in HHE genes, particularly those linked to cardiac EMT/EndMT, exacerbate the risk of recurrence.

Multiphysiologic State Computational Fluid Dynamics Modeling for Planning Fontan With Interrupted Inferior Vena Cava.

Background: Single 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. Objectives: The aim of the study was to utilize computational fluid dynamics (CFD) analysis to avoid maldistribution of HVF to the lungs after Fontan surgery. Methods: Four 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. Results: CFD 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%). Conclusions: A 3D modeling workflow with CFD simulation for SV patients with iIVC may avoid HVF maldistribution and development of AVMs after Fontan completion.

Evolving Role of Three-Dimensional Echocardiography for Right Ventricular Volume Analysis in Pediatric Heart Disease: Literature Review and Clinical Applications.

Accurate knowledge of right ventricular (RV) volumes and ejection fraction is fundamental to providing optimal care for pediatric patients with congenital and acquired heart disease, as well as pulmonary hypertension. Traditionally, these volumes have been measured using cardiac magnetic resonance because of its accuracy, reproducibility, and freedom from geometric assumptions. More recently, an increasing number of studies have described the measurement of RV volumes using three-dimensional (3D) echocardiography. In addition, volumes by 3D echocardiography have also been used for outcome research studies in congenital heart surgery. Importantly, 3D echocardiographic acquisitions can be obtained over a small number of cardiac cycles, do not require general anesthesia, and are less costly than CMR. The ease and safety of the 3D echocardiographic acquisitions allow serial studies in the same patient. Moreover, the studies can be performed in various locations, including the intensive care unit, catheterization laboratory, and general clinic. Because of these advantages, 3D echocardiography is ideal for serial evaluation of the same patient. Despite these potential advantages, 3D echocardiography has not become a standard practice in children with congenital and acquired heart conditions. In this report, the authors review the literature on the feasibility, reproducibility, and accuracy of 3D echocardiography in pediatric patients. In addition, the authors investigate the advantages and limitations of 3D echocardiography in RV quantification and offer a pathway for its potential to become a standard practice in the assessment, planning, and follow-up of congenital and acquired heart disease.

Right ventricular contraction patterns in healthy children using three-dimensional echocardiography.

Background: The right ventricle (RV) has complex geometry and function, with motion along three separate axes-longitudinal, radial, and anteroposterior. Quantitative assessment of RV function by two-dimension echocardiography (2DE) has been limited as a consequence of this complexity, whereas newer three dimensional (3D) analysis offers the potential for more comprehensive assessment of the contributors to RV function. The aims of this study were to quantify the longitudinal, radial and anteroposterior components of global RV function using 3D echocardiography in a cohort of healthy children and to examine maturational changes in these parameters. Methods: Three-dimensional contours of the RV were generated from a cohort of healthy pediatric patients with structurally normal hearts at two centers. Traditional 2D and 3D echo characteristics were recorded. Using offline analysis of 3D datasets, RV motion was decomposed into three components, and ejection fractions (EF) were calculated (longitudinal-LEF; radial-REF; and anteroposterior-AEF). The individual decomposed EF values were indexed against the global RVEF. Strain values were calculated as well. Results: Data from 166 subjects were included in the analysis; median age was 13.5 years (range 0 to 17.4 years). Overall, AEF was greater than REF and LEF (29.2 ± 6.2% vs. 25.1 ± 7.2% and 25.7 ± 6.0%, respectively; p < 0.001). This remained true when indexed to overall EF (49.8 ± 8.7% vs. 43.3 ± 11.6% and 44.4 ± 10%, respectively; p < 0.001). Age-related differences were present for global RVEF, REF, and all components of RV strain. Conclusions: In healthy children, anteroposterior shortening is the dominant component of RV contraction. Evaluation of 3D parameters of the RV in children is feasible and enhances the overall understanding of RV function, which may allow improvements in recognition of dysfunction and assessment of treatment effects in the future.

A comparison between the apical and subcostal view for three-dimensional echocardiographic assessment of right ventricular volumes in pediatric patients.

Background: Accurate measurement of ventricular volumes is an important clinical imaging goal. Three-dimensional echocardiography (3DEcho) is used increasingly as it is more available and less costly than cardiac magnetic resonance (CMR). For the right ventricle (RV), the current practice is to acquire 3DEcho volumes from the apical view. However, in some patients the RV may be better seen from the subcostal view. Therefore, this study compared RV volume measurements from the apical vs. the subcostal view, using CMR as a reference standard. Methods: Patients <18 years old undergoing a clinical CMR examination were prospectively enrolled. 3DEcho was performed on the day of the CMR. 3DEcho images were acquired with Philips Epic 7 ultrasound system from apical and subcostal views. Offline analysis was performed with TomTec 4DRV Function for 3DEcho images and cvi42 for CMR ones. RV end-diastolic volume and end-systolic volume were collected. Agreement between 3DEcho and CMR was assessed with Bland-Altman analysis and the intraclass correlation coefficient (ICC). Percentage (%) error was calculated using CMR as the reference standard. Results: Forty-seven patients were included in the analysis (age range 10 months to 16 years). The ICC was moderate to excellent for all volume comparisons to CMR (subcostal vs. CMR: end-diastolic volume 0.93, end-systolic volume 0.81; apical vs. CMR: end-diastolic volume 0.94, end-systolic volume 0.74).The 3DEcho mean % error vs. CMR for end-systolic volume was 25% for subcostal and 31% for apical; for end-diastolic volume it was 15% for subcostal and 16% for apical. The % error was not significantly different between apical vs. subcostal views for end-systolic and end-diastolic volume measurements. Conclusions: For apical and subcostal views, 3DEcho-derived ventricular volumes agree well with CMR. Neither echo view has a consistently smaller error when compared to CMR volumes. Accordingly, the subcostal view can be used as an alternative to the apical view when acquiring 3DEcho volumes in pediatric patients, particularly when the image quality from this window is superior.

Staged ventricular recruitment and biventricular conversion following single-ventricle palliation in unbalanced atrioventricular canal defects.

Objective: Restoration of biventricular circulation is an alternative management strategy in unbalanced atrioventricular canal defects (uAVCDs), especially in patients with risk factors for single-ventricle palliation (SVP) failure. When ventricular volume is inadequate for biventricular circulation, recruitment procedures may accommodate its growth. In this study, we review our uAVCD experience with biventricular conversion (BIVC) after prior SVP. Methods: This is a single-institution, retrospective cohort study of uAVCD patients who underwent BIVC after SVP, with staged recruitment (staged) or primary BIVC (direct) between 2003 to 2018. Mortality, unplanned reinterventions, imaging, and catheterization data were analyzed. Results: Sixty-five patients underwent BIVC from SVP (17 stage 1, 42 bidirectional Glenn, and 6 Fontan). Decision for conversion was based on poor SVP candidacy (n = 43) or 2 adequately sized ventricles (n = 22). Of the 65 patients, 20 patients underwent recruitment before conversion. The staged group had more severe ventricular hypoplasia than the direct group, reflected in prestaging end-diastolic volume z scores (-4.0 vs -2.6; P < .01), which significantly improved after recruitment (-4.0 to -1.8; P < .01). Median follow-up time was 1.0 years. Survival and recatheterizations were similar between both groups (hazard ratio, 0.9; 95% CI, 0.2-3.7; P = .95 and hazard ratio, 1.9; 95% CI, 0.9-4.1; P = .09), but more reoperations occurred with staged approach (hazard ratio, 3.1; 95% CI, 1.3-7.1; P = .01). Conclusions: Biventricular conversion from SVP is an alternative strategy to manage uAVCD, particularly when risk factors for SVP failure are present. Severe forms of uAVCDs can be converted with staged BIVC with acceptable mortality, albeit increased reinterventions, when primary BIVC is not possible.

Symmetric bicuspidizing repair for patients with congenital aortic or truncal valve disease.

OBJECTIVE: Symmetric bicuspidizing repair has been shown to be safe and effective in the short term in adults and children with unicuspid aortic valve. Outcomes of extending this technique to patients with other forms of aortic and truncal valve disease have not been reported. METHODS: We performed a retrospective review of patients who underwent the symmetric bicuspidizing repair at Boston Children's Hospital between December 2019 and June 2022 with a contemporary comparator group of patients who underwent other forms of bicuspidization. Survival, valve-related reoperation, and the development of moderate or greater aortic or truncal valve regurgitation were assessed. RESULTS: There were 23 patients who underwent symmetric bicuspidizing repair and 18 who underwent another form of bicuspidization. Preoperative aortic regurgitation was present in 87.0%. Patients who underwent symmetric bicuspidizing repair more commonly underwent suture annuloplasty (100% vs 55.6%; P = .002) and ascending aortoplasty (78.3% vs 27.8%; P = .004). There was 1 operative mortality (2.4%) in the entire cohort and 1 late mortality. Freedom from moderate aortic regurgitation was 87.5% at 21 months after symmetric bicuspidizing repair compared with 43.5% for patients who underwent other types of bicuspidization; P = .03. Freedom from valve-related reoperation was 100% in the symmetric bicuspidizing repair group compared with 64.4%; P = .02. CONCLUSIONS: The symmetric bicuspidizing repair may be safely extended to patients with various forms of congenital aortic and truncal valve disease. Longer term follow-up will be necessary to determine the comparative effectiveness of this technique compared with neocuspidization and the Ross procedure.

Residual Lesion Severity Predicts Midterm Outcomes After Congenital Aortic Valve Repair.

BACKGROUND: We sought to validate the technical performance score (TPS) as a predictor of midterm outcomes after congenital aortic valve repair. METHODS: This was a single-center, retrospective review of consecutive patients who underwent aortic valve repair between January 1, 2011, and December 31, 2019. Predischarge echocardiograms were used to assign a TPS for each index operation as class 1, no aortic valve residua; class 2, minor aortic valve residua; or class 3, major aortic valve residua or predischarge reintervention for major residua. The primary outcome was postdischarge (late) unplanned aortic valve reintervention. Secondary outcomes included late mortality and at least moderate aortic regurgitation or stenosis at the latest follow-up or before the earliest reintervention. Associations between TPS and outcomes were assessed using competing risk, Cox proportional hazards, or logistic regression models, adjusting for preoperative patient- and procedure-related covariates. RESULTS: Of 507 patients, there were 110 (21.7%) reinterventions, 22 (4.3%) deaths, and 67 (13.2%) cases of at least moderate aortic regurgitation or stenosis at the latest follow-up or earliest reintervention. On multivariable analysis, class 3 patients had a greater risk of reintervention (subdistribution hazard ratio, 2.6; 95% CI, 1.3-5.1; P = .005) and mortality (hazard ratio, 5.3; 95% CI. 1.1-25.2; P = .038) compared with class 1 patients. Adjusting for duration of follow-up, class 3 patients also had a greater risk of at least moderate aortic regurgitation or stenosis at the latest follow-up or earliest reintervention (odds ratio, 7.7; 95% CI, 2.5-24.2; P < .001) vs class 1 patients. CONCLUSIONS: Patients with major residua after congenital aortic valve repair have significantly worse midterm outcomes compared with those with no residua, warranting closer follow-up.

Recommendations for the Use of Echocardiography in the Evaluation of Rheumatic Heart Disease: A Report from the American Society of Echocardiography.

Acute rheumatic fever and its chronic sequela, rheumatic heart disease (RHD), pose major health problems globally, and remain the most common cardiovascular disease in children and young people worldwide. Echocardiography is the most important diagnostic tool in recognizing this preventable and treatable disease and plays an invaluable role in detecting the presence of subclinical disease needing prompt therapy or follow-up assessment. This document provides recommendations for the comprehensive use of echocardiography in the diagnosis and therapeutic intervention of RHD. Echocardiographic diagnosis of RHD is made when typical findings of valvular and subvalvular abnormalities are seen, including commissural fusion, leaflet thickening, and restricted leaflet mobility, with varying degrees of calcification. The mitral valve is predominantly affected, most often leading to mitral stenosis. Mixed valve disease and associated cardiopulmonary pathology are common. The severity of valvular lesions and hemodynamic effects on the cardiac chambers and pulmonary artery pressures should be rigorously examined. It is essential to take advantage of all available modalities of echocardiography to obtain accurate anatomic and hemodynamic details of the affected valve lesion(s) for diagnostic and strategic pre-treatment planning. Intraprocedural echocardiographic guidance is critical during catheter-based or surgical treatment of RHD, as is echocardiographic surveillance for post-intervention complications or disease progression. The role of echocardiography is indispensable in the entire spectrum of RHD management.

Prospective randomized controlled trial of the safety and feasibility of a novel mesenchymal precursor cell therapy in hypoplastic left heart syndrome.

Objective: To assess the safety and feasibility of low-dose, novel, allogenic mesenchymal precursor cell (MPC) therapy as an adjunct to left ventricular (LV) recruitment for patients with hypoplastic left heart syndrome (HLHS) and borderline left ventricles. MPC injections into the hypoplastic left ventricle may stimulate neovascularization and beneficial LV remodeling and may improve the likelihood of achieving biventricular (BiV) or 1.5 ventricle (1.5V) circulation. Methods: Children <5 years with prior single ventricle palliation undergoing LV recruitment surgery at a single center were randomized to MPC injections into the LV endocardium/papillary muscles (MPCs) or standard-of-care (controls) and followed for 24 months. The primary endpoint was safety, including (serious) adverse events (S/AEs), and panel reactive antibodies (PRAs). Secondary endpoints included BiV/1.5V conversion and LV size and function. Results: Nineteen subjects were enrolled, including 9 MPC recipients and 10 controls. Fourteen patients (74%) had >1 AE, and 2 patients had SAEs, both deemed unrelated to the trial product. AE severity and frequency were similar in the 2 groups. Baseline PRA levels were high, with no difference between the groups at 12 months. The overall probability of BiV/1.5V conversion was 0.16 (95% confidence interval [CI], 0.05 to 0.41) at 12 months and 0.52 (95% CI, 0.31 to 0.77) at 24 months. For patients with imaging data at both time points, increases in LV volumes from baseline to 12 months were larger in the MPC group by 3-dimensional echocardiography and cardiac magnetic resonance imaging. For children who successfully underwent BiV conversion (n = 12), full BiV conversion was achieved at 24 months in 5 of 5 (100%) MPC-treated children compared with 4 of 7 (57%) controls. Conclusions: MPC injections were considered safe and feasible in HLHS patients. More than 50% of subjects underwent BiV/1.5V conversion within 2 years. Larger trials are needed to investigate the therapeutic potential of MPCs in this population.

Case report: Active clinical manifestation of endocardial fibroelastosis in adolescence in a patient with mitral and aortic obstruction-histologic presence of endothelial-to-mesenchymal transformation.

This is the first description of active clinical manifestation of endocardial fibroelastosis (EFE) and remodeling of the endocardium via endothelial-to-mesenchymal transformation (EndMT) in an adolescent with Shone's variant hypoplastic left heart complex (HLHC) and a genetic heterozygous ABL1 variant. While EFE has not been typically associated HLHC or Shone's syndrome, in this patient flow alterations in the left ventricle (LV), combined with genetic alterations of intrinsic EndMT pathways led to active clinical manifestation of EFE in adolescence. This case emphasizes that new therapies for EFE might need to focus on molecular factors influenced by intrinsic and extrinsic stimuli of EndMT.

Contemporary outcomes of the double switch operation for congenitally corrected transposition of the great arteries.

OBJECTIVE: To determine the contemporary outcomes of the double switch operation (DSO) (ie, Mustard or Senning + arterial switch). METHODS: A single-institution, retrospective review of all patients with congenitally corrected transposition of the great arteries undergoing a DSO. RESULTS: Between 1999 and 2019, 103 patients underwent DSO with a Mustard (n = 93) or Senning (n = 10) procedure. Segmental anatomy was (S, L, L) in 93 patients and (I, D, D) in 6 patients. Eight patients had heterotaxy and 71 patients had a ventricular septal defect. Median age was 2.1 years (range, 1.8 months-40 years), including 34 patients younger than age 1 year (33%). Median weight was 10.9 kg (range, 3.4-64 kg). Sixty-one patients had prior pulmonary artery bands for a median of 1.1 years (range, 14 days-12.9 years; interquartile range, 0.7-3.1 years). Median intensive care unit and hospital lengths of stay were 5 and 10 days, respectively. Median follow-up was 3.4 years (interquartile range, 1-9.8 years) and 5.2 years (interquartile range, 2.3-10.7 years) in 79 patients with >1 year follow-up. At latest follow-up, aortic, mitral, tricuspid valve regurgitation, and left ventricle dysfunction was less than moderate in 96%, 98%, 96%, and 93%, respectively. Seventeen patients underwent reoperation: neoaortic valve intervention (n = 10), baffle revision (n = 5), and ventricular septal defect closure (n = 4). At latest follow-up, 17 patients (17%) had a pacemaker and 27 (26%) had cardiac resynchronization therapy devices. There were 2 deaths and 2 transplants. Transplant-free survival was 94.6% at 5 years. Risk factors for death or transplant included longer cardiopulmonary bypass time and older age at DSO. CONCLUSIONS: The outcomes of the DSO are promising. Earlier age at operation might favor better outcomes. Progressive neoaortic regurgitation and reinterventions on the neo-aortic valve are anticipated problems.

Visualization and Quantification of the Unrepaired Complete Atrioventricular Canal Valve Using Open-Source Software.

BACKGROUND: Repair of complete atrioventricular canal (CAVC) is often complicated by residual left atrioventricular valve regurgitation. The structure of the mitral and tricuspid valves in biventricular hearts has previously been shown to be associated with valve dysfunction. However, the three-dimensional (3D) structure of the entire unrepaired CAVC valve has not been quantified. Understanding the 3D structure of the CAVC may inform optimized repair. METHODS: Novel open-source work flows were created in SlicerHeart for the modeling and quantification of CAVC valves on the basis of 3D echocardiographic images. These methods were applied to model the annulus, leaflets, and papillary muscle (PM) structure of 35 patients (29 with trisomy 21) with CAVC using transthoracic 3D echocardiography. The mean leaflet and annular shapes were calculated and visualized using shape analysis. Metrics of the complete native CAVC valve structure were compared with those of normal mitral valves using the Mann-Whitney U test. Associations between CAVC structure and atrioventricular valve regurgitation were analyzed. RESULTS: CAVC leaflet metrics varied throughout systole. Compared with normal mitral valves, the left CAVC PMs were more acutely angled in relation to the annular plane (P < .001). In addition, the anterolateral PM was laterally and inferiorly rotated in CAVC, while the posteromedial PM was more superiorly and laterally rotated, relative to normal mitral valves (P < .001). Lower native CAVC atrioventricular valve annular height and annular height-to-valve width ratio before repair were both associated with moderate or greater left atrioventricular valve regurgitation after repair (P < .01). CONCLUSIONS: It is feasible to model and quantify 3D CAVC structure using 3D echocardiographic images. The results demonstrate significant variation in CAVC structure across the cohort and differences in annular, leaflet, and PM structure compared with the mitral valve. These tools may be used in future studies to catalyze future research intended to identify structural associations of valve dysfunction and to optimize repair in this vulnerable and complex population.

Three-Dimensional Echocardiography Right Ventricular Volumes and Ejection Fraction Reference Values in Children: A North American Multicentre Study.

BACKGROUND: Three-dimensional echocardiography (3DE) evaluation of right ventricular (RV) volumes and ejection fraction (EF) is increasingly used for clinical serial assessments and management in children. This study aims to generate sex-specific reference values and z-score equations for RV volumetric parameters, independent of age and body size indices, derived from multiple populations across North America. METHODS: We prospectively recruited 455 healthy children (ages 0 to 18 years) from 5 centres. 3DE of the RV were acquired using various vendors with analyses performed offline using vendor-independent software. 3DE datasets with all walls of the RV endocardium visible were included. We reported data on RV EF, and generated z scores for end-systolic volumes (ESV), end-diastolic volumes (EDV) and stroke volume (SV). Differences between the sexes were explored. RESULTS: Of 455 3DE datasets, 312 (68%) met imaging criteria for analysis. Median age was 10.1 years (interquartile ratio [IQR]: 5.6, 14.0) with 17% being younger than 3 years of age. The mean and standard deviation for RV EDV, ESV, and SV for male and female patients were reported. We provided a downloadable z-score calculator with height and weight as independent variables to facilitate clinical utility. Although statistically significant differences between male and female RVEF was present (female 52.9 ± 3.9% vs male 51.6 ± 3.5%, P = 0.006), after adjusting for age, height, and weight, the magnitude of difference was clinically insignificant. CONCLUSIONS: Sex-specific reference values for pediatric RV volumes and EF, and z-score equations were derived from children 3DE datasets across 5 centres in North America.

Dynamic Annular Modeling of the Unrepaired Complete Atrioventricular Canal Annulus.

BACKGROUND: Repair of complete atrioventricular canal (CAVC) is often complicated by atrioventricular valve regurgitation, particularly of the left-sided valve. Understanding the 3-dimensional (3D) structure of the atrioventricular canal annulus before repair may help to inform optimized repair. However, the 3D shape and movement of the CAVC annulus has been neither quantified nor rigorously compared with a normal mitral valve annulus. METHODS: The complete annuli of 43 patients with CAVC were modeled in 4 cardiac phases using transthoracic 3D echocardiograms and custom code. The annular structure was compared with the annuli of 20 normal pediatric mitral valves using 3D metrics and statistical shape analysis (Procrustes analysis). RESULTS: The unrepaired CAVC annulus varied in shape significantly throughout the cardiac cycle. Procrustes analysis visually demonstrated that the average normalized CAVC annular shape is more planar than the normal mitral annulus. Quantitatively, the annular height-to-valve width ratio of the native left CAVC atrioventricular valve was significantly lower than that of a normal mitral valve in all systolic phases (P < .001). CONCLUSIONS: The left half of the CAVC annulus is more planar than that of a normal mitral valve with an annular height-to-valve width ratio similar to dysfunctional mitral valves. Given the known importance of annular shape to mitral valve function, further exploration of the association of 3D structure to valve function in CAVC is warranted.

Restriction of Atrial Septal Defect Leads to Growth of Hypoplastic Ventricle in Patients with Borderline Right or Left Heart.

Patients with borderline hypoplastic right or left ventricle and VSD may be candidates for either single ventricle palliation or staged ventricular recruitment (SVR) followed by eventual biventricular conversion. Components of SVR include restriction of atrial septal defects (ASD) without ventricular septal defects (VSD) closure and addition of accessory pulmonary blood flow. This study evaluated the impact of ASD restriction on ventricular growth and function. We retrospectively reviewed patients with borderline ventricular hypoplasia and VSD who underwent a staged ventricular recruitment (SVR) procedure from 2012 to June 2019. Pre- and post-recruitment MRI and echocardiogram data were compared and analyzed. We excluded cases in which we intentionally restricted VSD with simultaneous ASD restriction. Forty-six patients (41 with right-dominant ventricle, 25 with risk factors for Fontan procedure) underwent SVR at a median age of 15.1 months' (interquartile range (IQR), 7.2-37.2 months'). The median indexed ventricular end-diastolic volume, end-systolic volume, and stroke volume according to cardiac MRI significantly increased at median 11.0 months' (IQR:7.8~14.1 months') after recruitment. Among them, except 2 operative mortalities after SVR, 26 patients underwent bi-ventricular repair (56.5% including one and a half ventricle repair) at a median of 8.0 months' (IQR: 6.2-12.2 months') after recruitment. Fifteen patients await biventricular completion, and 3 patients underwent single ventricle palliation. Pulmonary blood flow (Qp) tended to increase after recruitment regardless of type of pulmonary blood flow modification without statistical significance. Six patients died at a median duration of 6.5 months' (IQR: 2.9-11.7) after SVR; 3 patients died after biventricular completion, 2 after recruitment, and 1 after returning to single ventricle palliation. All of them were considered poor Fontan candidates due to severe atrioventricular valve regurgitation, pulmonary hypertension, pulmonary vein stenosis, or airway stenosis. Restriction of the atrial septum leads to the growth of hypoplastic ventricle in patients with ventricular septal defects who undergo SVR regardless of the preoperative characteristics, and eventual biventricular repair can be performed in a subgroup of these patients. Future work is necessary to optimize timing of SVR and method of accessory pulmonary blood flow.

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.