A deep learning approach for fully automated cardiac shape modeling in tetralogy of Fallot.

BACKGROUND: Cardiac shape modeling is a useful computational tool that has provided quantitative insights into the mechanisms underlying dysfunction in heart disease. The manual input and time required to make cardiac shape models, however, limits their clinical utility. Here we present an end-to-end pipeline that uses deep learning for automated view classification, slice selection, phase selection, anatomical landmark localization, and myocardial image segmentation for the automated generation of three-dimensional, biventricular shape models. With this approach, we aim to make cardiac shape modeling a more robust and broadly applicable tool that has processing times consistent with clinical workflows. METHODS: Cardiovascular magnetic resonance (CMR) images from a cohort of 123 patients with repaired tetralogy of Fallot (rTOF) from two internal sites were used to train and validate each step in the automated pipeline. The complete automated pipeline was tested using CMR images from a cohort of 12 rTOF patients from an internal site and 18 rTOF patients from an external site. Manually and automatically generated shape models from the test set were compared using Euclidean projection distances, global ventricular measurements, and atlas-based shape mode scores. RESULTS: The mean absolute error (MAE) between manually and automatically generated shape models in the test set was similar to the voxel resolution of the original CMR images for end-diastolic models (MAE = 1.9 ± 0.5 mm) and end-systolic models (MAE = 2.1 ± 0.7 mm). Global ventricular measurements computed from automated models were in good agreement with those computed from manual models. The average mean absolute difference in shape mode Z-score between manually and automatically generated models was 0.5 standard deviations for the first 20 modes of a reference statistical shape atlas. CONCLUSIONS: Using deep learning, accurate three-dimensional, biventricular shape models can be reliably created. This fully automated end-to-end approach dramatically reduces the manual input required to create shape models, thereby enabling the rapid analysis of large-scale datasets and the potential to deploy statistical atlas-based analyses in point-of-care clinical settings. Training data and networks are available from cardiacatlas.org.

Right-left ventricular shape variations in tetralogy of Fallot: associations with pulmonary regurgitation.

BACKGROUND: Relationships between right ventricular (RV) and left ventricular (LV) shape and function may be useful in determining optimal timing for pulmonary valve replacement in patients with repaired tetralogy of Fallot (rTOF). However, these are multivariate and difficult to quantify. We aimed to quantify variations in biventricular shape associated with pulmonary regurgitant volume (PRV) in rTOF using a biventricular atlas. METHODS: In this cross-sectional retrospective study, a biventricular shape model was customized to cardiovascular magnetic resonance (CMR) images from 88 rTOF patients (median age 16, inter-quartile range 11.8-24.3 years). Morphometric scores quantifying biventricular shape at end-diastole and end-systole were computed using principal component analysis. Multivariate linear regression was used to quantify biventricular shape associations with PRV, corrected for age, sex, height, and weight. Regional associations were confirmed by univariate correlations with distances and angles computed from the models, as well as global systolic strains computed from changes in arc length from end-diastole to end-systole. RESULTS: PRV was significantly associated with 5 biventricular morphometric scores, independent of covariates, and accounted for 12.3% of total shape variation (p < 0.05). Increasing PRV was associated with RV dilation and basal bulging, in conjunction with decreased LV septal-lateral dimension (LV flattening) and systolic septal motion towards the RV (all p < 0.05). Increased global RV radial, longitudinal, circumferential and LV radial systolic strains were significantly associated with increased PRV (all p < 0.05). CONCLUSION: A biventricular atlas of rTOF patients quantified multivariate relationships between left-right ventricular morphometry and wall motion with pulmonary regurgitation. Regional RV dilation, LV reduction, LV septal-lateral flattening and increased RV strain were all associated with increased pulmonary regurgitant volume. Morphometric scores provide simple metrics linking mechanisms for structural and functional alteration with important clinical indices.

Evaluation of Impedance Cardiography for Measurement of Stroke Volume in Congenital Heart Disease.

Noninvasive measurement of cardiac output (CO) and particularly stroke volume (SV) remain difficult but potentially valuable. These variables can be particularly challenging to measure in children with congenital heart disease (CHD). Impedance cardiography (IC) is a technique shown to be accurate in measuring SV in adults and in children with structurally normal hearts. The ease of use and rapidity of SV measurement using IC makes it potentially attractive for young patients with CHD. Advances in IC technology have led to more sophisticated signal-morphology IC (SMIC) devices that may further improve accuracy. We tested the accuracy of SMIC to measure SV in 21 subjects with CHD by comparing measurements with those from cardiac magnetic resonance (CMR) imaging. There was good agreement between SMIC and CMR in measurement of SV: mean difference = 1.7 ml (p = 0.47); r = 0.89. The agreement and correlation persisted when controlling for the differences in blood pressure and heart rate during the two testing methods. We conclude that SMIC is accurate at measuring SV and thus CO when compared to CMR in a variety of forms of CHD.

Atlas-Based Ventricular Shape Analysis for Understanding Congenital Heart Disease.

Congenital heart disease is associated with abnormal ventricular shape that can affect wall mechanics and may be predictive of long-term adverse outcomes. Atlas-based parametric shape analysis was used to analyze ventricular geometries of eight adolescent or adult single-ventricle CHD patients with tricuspid atresia and Fontans. These patients were compared with an "atlas" of non-congenital asymptomatic volunteers, resulting in a set of z-scores which quantify deviations from the control population distribution on a patient-by-patient basis. We examined the potential of these scores to: (1) quantify abnormalities of ventricular geometry in single ventricle physiologies relative to the normal population; (2) comprehensively quantify wall motion in CHD patients; and (3) identify possible relationships between ventricular shape and wall motion that may reflect underlying functional defects or remodeling in CHD patients. CHD ventricular geometries at end-diastole and end-systole were individually compared with statistical shape properties of an asymptomatic population from the Cardiac Atlas Project. Shape analysis-derived model properties, and myocardial wall motions between end-diastole and end-systole, were compared with physician observations of clinical functional parameters. Relationships between altered shape and altered function were evaluated via correlations between atlas-based shape and wall motion scores. Atlas-based shape analysis identified a diverse set of specific quantifiable abnormalities in ventricular geometry or myocardial wall motion in all subjects. Moreover, this initial cohort displayed significant relationships between specific shape abnormalities such as increased ventricular sphericity and functional defects in myocardial deformation, such as decreased long-axis wall motion. These findings suggest that atlas-based ventricular shape analysis may be a useful new tool in the management of patients with CHD who are at risk of impaired ventricular wall mechanics and chamber remodeling.

Device therapy for atrial septal defects in a multicenter cohort: acute outcomes and adverse events.

BACKGROUND: Secundum atrial septal defect (ASD) closure devices were granted approval based on industry-sponsored, prospective, nonrandomized, single device studies, demonstrating acceptable efficacy and safety in selected patients. We sought to report community practice and outcomes. METHODS AND RESULTS: Procedure specific data was collected on cases considered for ASD closure in the congenital cardiac catheterization project on outcomes (C3PO) between February 1, 2007 and June 31, 2010. Eight centers contributed data during this time period. All adverse events (AE) were independently reviewed and classified by a five level severity scale. In 40 months (2/07-6/10), 653 of 688 ASDs were occluded with a single device using an AMPLATZER(®) Septal Occluder (ASO) in 566 (87%), GORE(®) HELEX(®) Septal Occluder (HSO) in 33 (5%), and a CardioSEAL(®) or STARFlex™ device (CSD) in 54 (8%). Most patients had an isolated ASD (93%). 85% were >2 years of age. The ASD median diameter was 12 mm [8,16] for ASO, with smaller diameters in HSO 8 mm [7,10] and CSD 8 mm [5,10] (P < 0.001). AE (n = 82) were recorded in 76 cases, 11.5% (95% CI 9.2%, 14.1%) and classified as high severity in 4.7% (95% CI 3.2%, 6.5%), with no mortality. A new conduction abnormality was detected during 15 cases and did not resolve in one. Transcatheter device retrieval was possible in 7 of 10 device embolizations. Device erosion occurred in 3 of 566, 0.5% (95% CI 0.1%, 1.5%), ASO implants. CONCLUSION: Although device closure of ASDs is associated with low morbidity and rare mortality, ongoing assessment of device safety profiles are warranted, and registries offer opportunities to facilitate the required surveillance.

Incidence and management of life-threatening adverse events during cardiac catheterization for congenital heart disease.

Continued advancements in congenital cardiac catheterization and interventions have resulted in increased patient and procedural complexity. Anticipation of life-threatening events and required rescue measures is a critical component to preprocedural preparation. We sought to determine the incidence and nature of life-threatening adverse events in congenital and pediatric cardiac catheterization, risk factors, and resources necessary to anticipate and manage events. Data from 8905 cases performed at the 8 participating institutions of the Congenital Cardiac Catheterization Project on Outcomes were captured between 2007 and 2010 [median 1,095/site (range 133-3,802)]. The incidence of all life-threatening events was 2.1 % [95 % confidence interval (CI) 1.8-2.4 %], whereas mortality was 0.28 % (95 % CI 0.18-0.41 %). Fifty-seven life-threatening events required cardiopulmonary resuscitation, whereas 9 % required extracorporeal membrane oxygenation. Use of a risk adjustment model showed that age <1 year [odd ratio (OR) 1.9, 95 % CI 1.4-2.7, p < 0.001], hemodynamic vulnerability (OR 1.6, 95 % CI 1.1-2.3, p < 0.01), and procedure risk (category 3: OR 2.3, 95 % CI 1.3-4.1; category 4: OR 4.2, 95 % CI 2.4-7.4) were predictors of life-threatening events. Using this model, standardized life-threatening event ratios were calculated, thus showing that one institution had a life-threatening event rate greater than expected. Congenital cardiac catheterization and intervention can be performed safely with a low rate of life-threatening events and mortality; preprocedural evaluation of risk may optimize preparation of emergency rescue and bailout procedures. Risk predictors (age < 1, hemodynamic vulnerability, and procedure risk category) can enhance preprocedural patient risk stratification and planning.

A universal biventricular coordinate system incorporating valve annuli: Validation in congenital heart disease.

Universal coordinate systems have been proposed to facilitate anatomic registration between three-dimensional images, data and models of the ventricles of the heart. However, current universal ventricular coordinate systems do not account for the outflow tracts and valve annuli where the anatomy is complex. Here we propose an extension to the 'Cobiveco' biventricular coordinate system that also accounts for the intervalvular bridges of the base and provides a tool for anatomically consistent registration between widely varying biventricular shapes. CobivecoX uses a novel algorithm to separate intervalvular bridges and assign new coordinates, including an inflow-outflow coordinate, to describe local positions in these regions uniquely and consistently. Anatomic consistency of registration was validated using curated three-dimensional biventricular shape models derived from cardiac MRI measurements in normal hearts and hearts from patients with congenital heart diseases. This new method allows the advantages of universal cardiac coordinates to be used for three-dimensional ventricular imaging data and models that include the left and right ventricular outflow tracts and valve annuli.

Biventricular shape modes discriminate pulmonary valve replacement in tetralogy of Fallot better than imaging indices.

Current indications for pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (rTOF) rely on cardiovascular magnetic resonance (CMR) image-based indices but are inconsistently applied, lead to mixed outcomes, and remain debated. This study aimed to test the hypothesis that specific markers of biventricular shape may discriminate differences between rTOF patients who did and did not require subsequent PVR better than standard imaging indices. In this cross-sectional retrospective study, biventricular shape models were customized to CMR images from 84 rTOF patients. A statistical atlas of end-diastolic shape was constructed using principal component analysis. Multivariate regression was used to quantify shape mode and imaging index associations with subsequent intervention status (PVR, n = 48 vs. No-PVR, n = 36), while accounting for confounders. Clustering analysis was used to test the ability of the most significant shape modes and imaging indices to discriminate PVR status as evaluated by a Matthews correlation coefficient (MCC). Geometric strain analysis was also conducted to assess shape mode associations with systolic function. PVR status correlated significantly with shape modes associated with right ventricular (RV) apical dilation and left ventricular (LV) dilation (p < 0.01), RV basal bulging and LV conicity (p < 0.05), and pulmonary valve dilation (p < 0.01). PVR status also correlated significantly with RV ejection fraction (p < 0.05) and correlated marginally with LV end-systolic volume index (p < 0.07). Shape modes discriminated subsequent PVR better than standard imaging indices (MCC = 0.49 and MCC = 0.28, respectively) and were significantly associated with RV and LV radial systolic strain. Biventricular shape modes discriminated differences between patients who did and did not require subsequent PVR better than standard imaging indices in current use. These regional features of cardiac morphology may provide insight into adaptive vs. maladaptive types of structural remodeling and point toward an improved quantitative, patient-specific assessment tool for clinical use.

An Atlas-Based Analysis of Biventricular Mechanics in Tetralogy of Fallot.

The current study proposes an efficient strategy for exploiting the statistical power of cardiac atlases to investigate whether clinically significant variations in ventricular shape are sufficient to explain corresponding differences in ventricular wall motion directly, or if they are indirect markers of altered myocardial mechanical properties. This study was conducted in a cohort of patients with repaired tetralogy of Fallot (rTOF) that face long-term right ventricular (RV) and/or left ventricular (LV) dysfunction as a consequence of adverse remodeling. Features of biventricular end-diastolic (ED) shape associated with RV apical dilation, LV dilation, RV basal bulging, and LV conicity correlated with components of systolic wall motion (SWM) that contribute most to differences in global systolic function. A finite element analysis of systolic biventricular mechanics was employed to assess the effect of perturbations in these ED shape modes on corresponding components of SWM. Perturbations to ED shape modes and myocardial contractility explained observed variation in SWM to varying degrees. In some cases, shape markers were partial determinants of systolic function and, in other cases, they were indirect markers for altered myocardial mechanical properties. Patients with rTOF may benefit from an atlas-based analysis of biventricular mechanics to improve prognosis and gain mechanistic insight into underlying myocardial pathophysiology.

Purpose-Built Transcatheter Cavopulmonary Anastomosis Device Requirements: Multi-Modality Imaging Evaluation.

BACKGROUND/PURPOSE: Patients with a functional single ventricle undergo multiple, palliative open-heart surgeries. This includes a superior cavopulmonary anastomosis or bidirectional Glenn shunt. A less-invasive transcatheter approach may reduce morbidity. METHODS/MATERIALS: We analyzed pre-Glenn X-ray contrast angiography (XA), cardiac computed tomography (CT), and cardiac magnetic resonance (CMR) studies. RESULTS: Over an eleven-year period (1/2007 - 6/2017), 139 Glenn surgeries were performed at our institution. The typical age range at surgery was 59 - 371 days (median = 163; IQR = 138 - 203). Eight-nine XA, ten CT, and ten CMR studies obtained from these patients were analyzed. Cephalad SVC measurements (millimeters) were 7.3 ± 1.7 (XA), 7.7 ± 1.6 (CT) and 6.9 ± 1.8 (CMR). RPA measurements were 7.3 ± 1.9 (XA), 7.4 ± 1.6 (CT) and 6.6 ± 1.9 (CMR). Potential device lengths were 10.9 ± 6 - 17.4 ± 6.4 (XA), 10.1 ± 2.1 - 17.7 ± 2.4 (CT) and 17.3 ± 4. - 23.7 ± 5.5 (CMR). SVC-RPA angle (degrees) was 132.9 ± 13.2 (CT) and 140 ± 10.2 (MRI). Image quality of all CT (100%), almost all XA (SVC 100%, RPA 99%), and most MRI (SVC 80%, RPA 90%) were deemed sufficient. Parametric modeling virtual fit device with 10 mm diameter and 20 - 25 mm length was ideal. CONCLUSIONS: Ideal transcatheter cavopulmonary shunt device for the typical patient would be 10 mm in diameter and 20-25 mm in length.

Neonatal Myocardial Infarction: A Proposed Algorithm for Coronary Arterial Thrombus Management.

BACKGROUND: Neonatal myocardial infarction is rare and is associated with a high mortality of 40% to 50%. We report our experience with neonatal myocardial infarction, including presentation, management, outcomes, and our current patient management algorithm. METHODS: We reviewed all infants admitted with a diagnosis of coronary artery thrombosis, coronary ischemia, or myocardial infarction between January 2015 and May 2021. RESULTS: We identified 21 patients (median age, 1 [interquartile range (IQR), 0.25-9.00] day; weight, 3.2 [IQR, 2.9-3.7] kg). Presentation included respiratory distress (16), shock (3), and murmur (2). Regional wall motion abnormalities by echocardiogram were a key criterion for diagnosis and were present in all 21 with varying degrees of depressed left ventricular function (severe [8], moderate [6], mild [2], and low normal [5]). Ejection fraction ranged from 20% to 54% (median, 43% [IQR, 34%-51%]). Mitral regurgitation was present in 19 (90%), left atrial dilation in 15 (71%), and pulmonary hypertension in 18 (86%). ECG was abnormal in 19 (90%). Median troponin I was 0.18 (IQR, 0.12-0.56) ng/mL. Median BNP (B-type natriuretic peptide) was 2100 (IQR, 924-2325) pg/mL. Seventeen had documented coronary thrombosis by cardiac catheterization. Seventeen (81%) were treated with intracoronary tPA (tissue-type plasminogen activator) followed by systemic heparin, AT (antithrombin), and intravenous nitroglycerin, and 4 (19%) were treated with systemic heparin, AT, and intravenous nitroglycerin alone. Nineteen of 21 recovered. One died (also had infradiaphragmatic total anomalous pulmonary venous return). One patient required a ventricular assist device and later underwent heart transplant; this patient was diagnosed late at 5 weeks of age and did not respond to tPA. Nineteen of 21 (90%) regained normal left ventricular function (ejection fraction, 60%-74%; mean, 65% [IQR, 61%-67%]) at latest follow-up (median, 6.8 [IQR, 3.58-14.72] months). Two of 21 (10%) had residual trivial mitral regurgitation. After analysis of these results, we present our current algorithm, which developed and matured over time, to manage neonatal myocardial infarction. CONCLUSIONS: We experienced a lower mortality rate for infants with neonatal infarction than that reported in the literature. We propose a post hoc algorithm that may lead to improvement in patient outcomes following coronary artery thrombus.

Accuracy of Cardiac Magnetic Resonance Imaging in Diagnosing Pediatric Cardiac Masses: A Multicenter Study.

BACKGROUND: After diagnosis of a cardiac mass, clinicians must weigh the benefits and risks of ascertaining a tissue diagnosis. Limited data are available on the accuracy of previously developed noninvasive pediatric cardiac magnetic resonance (CMR)-based diagnostic criteria. OBJECTIVES: The goals of this study were to: 1) evaluate the CMR characteristics of pediatric cardiac masses from a large international cohort; 2) test the accuracy of previously developed CMR-based diagnostic criteria; and 3) expand diagnostic criteria using new information. METHODS: CMR studies (children 0-18 years of age) with confirmatory histological and/or genetic diagnosis were analyzed by 2 reviewers, without knowledge of prior diagnosis. Diagnostic accuracy was graded as: 1) single correct diagnosis; 2) correct diagnosis among a differential; or 3) incorrect diagnosis. RESULTS: Of 213 cases, 174 (82%) had diagnoses that were represented in the previously published diagnostic criteria. In 70% of 174 cases, both reviewers achieved a single correct diagnosis (94% of fibromas, 71% of rhabdomyomas, and 50% of myxomas). When ≤2 differential diagnoses were included, both reviewers reached a correct diagnosis in 86% of cases. Of 29 malignant tumors, both reviewers indicated malignancy as a single diagnosis in 52% of cases. Including ≤2 differential diagnoses, both reviewers indicated malignancy in 83% of cases. Of 6 CMR sequences examined, acquisition of first-pass perfusion and late gadolinium enhancement were independently associated with a higher likelihood of a single correct diagnosis. CONCLUSIONS: CMR of cardiac masses in children leads to an accurate diagnosis in most cases. A comprehensive imaging protocol is associated with higher diagnostic accuracy.

Detection of coronary artery anomalies in infants and young children with congenital heart disease by using MR imaging.

PURPOSE: To evaluate the feasibility and accuracy of magnetic resonance (MR) coronary angiography for the detection of coronary artery anomalies in infants and children by using surgical findings as a reference. MATERIALS AND METHODS: The data analysis was approved by the institutional review board. One hundred children with congenital heart disease underwent MR coronary angiography while under general anesthesia (mean age ± standard deviation, 3.9 years ± 3; age range, 0.2-11 years). A navigator-gated, T2-prepared, three-dimensional steady-state free precession whole-heart protocol (isotropic voxel size, 1.0-1.3 mm(3); mean imaging time, 4.6 minutes ± 1.2; mean navigator efficiency, 70%; 3-mm gating window) was used after injection of gadopentetate dimeglumine. The cardiac rest period (end systole or middiastole) and acquisition window were prospectively assessed for each patient. Coronary artery image quality (score of 0 [nondiagnostic] to 4 [excellent]), vessel sharpness, and coronary artery anomalies were assessed by two observers. Surgery was performed in 58 patients, and those findings were used to define accuracy. Variables were assessed between age groups by using either analysis of variance or Kruskal-Wallis tests. RESULTS: Diagnostic image quality (score, ≥1 for all coronary artery segments) was obtained in 46 of the 58 patients (79%) who underwent surgery. The origin and course of the coronary artery anatomy depicted with MR imaging was confirmed at surgery in all 46 patients-including the four (9%) with substantial coronary artery anomalies. Diagnostic-quality images were obtained in 84 of the 100 patients. The rate of success improved significantly when patients were older than 4 months (88% for patients >4 months vs 17% for patients ≤4 months, P < .001). CONCLUSION: Improved whole-heart MR coronary angiography enables accurate detection of abnormal origin and course of the coronary artery system even in very young patients with congenital heart disease.

Computational analysis of cardiac structure and function in congenital heart disease: Translating discoveries to clinical strategies.

Increased availability and access to medical image data has enabled more quantitative approaches to clinical diagnosis, prognosis, and treatment planning for congenital heart disease. Here we present an overview of long-term clinical management of tetralogy of Fallot (TOF) and its intersection with novel computational and data science approaches to discovering biomarkers of functional and prognostic importance. Efforts in translational medicine that seek to address the clinical challenges associated with cardiovascular diseases using personalized and precision-based approaches are then discussed. The considerations and challenges of translational cardiovascular medicine are reviewed, and examples of digital platforms with collaborative, cloud-based, and scalable design are provided.

Atlas-based measures of left ventricular shape may improve characterization of adverse remodeling in anthracycline-exposed childhood cancer survivors: a cross-sectional imaging study.

BACKGROUND: Adverse cardiac remodeling is an important precursor to anthracycline-related cardiac dysfunction, however conventional remodeling indices are limited. We sought to examine the utility of statistical atlas-derived measures of ventricular shape to improve the identification of adverse anthracycline-related remodeling in childhood cancer survivors. METHODS: We analyzed cardiac magnetic resonance imaging from a cross-sectional cohort of 20 childhood cancer survivors who were treated with low (< 250 mg/m2 [N = 10]) or high (≥250 mg/m2 [N = 10]) dose anthracyclines, matched 1:1 by sex and age between dose groups. We reconstructed 3D computational models of left ventricular end-diastolic shape for each subject and assessed the ability of conventional remodeling indices (volume, mass, and mass to volume ratio) vs. shape modes derived from a statistical shape atlas of an asymptomatic reference population to stratify anthracycline-related remodeling. We compared conventional parameters and five atlas-based shape modes: 1) between survivors and the reference population (N = 1991) using multivariable linear regression, and 2) within survivors by anthracycline dose (low versus high) using two-sided T-tests, multivariable logistic regression, and receiver operating characteristic curves. RESULTS: Compared with the reference population, survivors had differences in conventional measures (lower volume and mass) and shape modes (corresponding to lower overall size and lower sphericity; all p < 0.001). Among survivors, differences in a shape mode corresponding to increased basal cavity size and altered mitral annular orientation in the high-dose group were observed (p = 0.039). Collectively, atlas-based shape modes in conjunction with conventional measures discriminated survivors who received low vs. high anthracycline dosage (area under the curve [AUC] 0.930, 95% confidence interval 0.816, 1.00) significantly better than conventional measures alone (AUC 0.710, 95% confidence interval 0.473, 0.947; AUC comparison p = 0.0498). CONCLUSIONS: Compared with a reference population, heart size is smaller in anthracycline-exposed childhood cancer survivors. Atlas-based measures of left ventricular shape may improve the detection of anthracycline dose-related remodeling differences.

Exercise MRI highlights heterogeneity in cardiovascular mechanics among patients with Fontan circulation: proposed protocol for routine evaluation.

Single ventricle physiology and palliation via the Fontan operation lead to a series of cardiovascular changes. In addition, organs such as the kidneys and liver have been shown to experience insults and subsequent injury. This has led to routine surveillance of patients. We present findings from a small cohort of patients that was deeply phenotyped to illustrate the need for comprehensive evaluation. A cohort of four Fontan patients with fairly high cardiovascular function was recruited 5-10 years post-Fontan. Patients underwent a rigorous clinical work-up after which a research MRI scan was performed during which (I) data were obtained during exercise to evaluate changes in stroke volume during supine exercise and (II) magnetic resonance angiograms with phase-contrast images were obtained for computational modeling of flows through the Fontan circulation at rest. Clinical measures were consistent with a fairly homogeneous high function cohort (peak oxygen consumption >20 mL/kg/min, robust response to exercise, peak ventilatory efficiency below levels associated with heart failure, MR-derived ejection fraction >50%). Liver evaluation did not reveal clear signs of cirrhosis or extensive fibrosis. However, we observed considerable variability (27-162%) in the increase in stroke index with exercise [100%±64% increase, 53.9±17.4 mL/beat m2 (rest), 101.1±20.7 mL/beat m2, (exercise)]. Computational flow modeling at rest in two patients also showed marked differences in flow distribution and shear stress. We report marked differences in both changes in stroke index during an exercise MRI protocol as well as computational flow patterns at rest suggesting different compensation strategies may be associated with high functioning Fontan patients. The observed heterogeneity illustrates the need for deep phenotyping to capture patient-specific adaptive mechanisms.

Fontan Revision: Presurgical Planning Using Four-Dimensional (4D) Flow and Three-Dimensional (3D) Printing.

Pulmonary arteriovenous malformations (AVMs) can be a complication of certain postoperative Fontan patients whose hepatic venous blood return is not distributed evenly to both lungs. A ten-year-old female, who had previously undergone staged single ventricle palliation for complex congenital heart disease, underwent a Fontan revision due to significant left-sided pulmonary AVMs and increasing arterial oxygen desaturation. The combination of four-dimensional flow cardiac magnetic resonance imaging and three-dimensional printing enabled presurgical planning for a Fontan takedown and diversion of hepatic venous flow to the azygous vein that resulted in significant clinical improvement.

Atlas-Based Computational Analysis of Heart Shape and Function in Congenital Heart Disease.

Approximately 1% of all babies are born with some form of congenital heart defect. Many serious forms of CHD can now be surgically corrected after birth, which has led to improved survival into adulthood. However, many patients require serial monitoring to evaluate progression of heart failure and determine timing of interventions. Accurate multidimensional quantification of regional heart shape and function is required for characterizing these patients. A computational atlas of single ventricle and biventricular heart shape and function enables quantification of remodeling in terms of z scores in relation to specific reference populations. Progression of disease can then be monitored effectively by longitudinal evaluation of z scores. A biomechanical analysis of cardiac function in relation to population variation enables investigation of the underlying mechanisms for developing pathology. Here, we summarize recent progress in this field, with examples in single ventricle and biventricular congenital pathologies.

First-in-Human Closed-Chest Transcatheter Superior Cavopulmonary Anastomosis.

BACKGROUND: In the care of patients with congenital heart disease, percutaneous interventional treatments have supplanted many surgical approaches for simple lesions, such as atrial septal defect. By contrast, complex congenital heart defects continue to require open-heart surgery. In single-ventricle patients, a staged approach is employed, which requires multiple open-heart surgeries and significant attendant morbidity and mortality. A nonsurgical transcatheter alternative would be attractive. OBJECTIVES: The authors sought to show the feasibility of catheter-only, closed-chest, large-vessel anastomosis (superior vena cava and pulmonary artery [PA] or bidirectional Glenn operation equivalent) in a patient. METHODS: In preclinical testing over a decade, the authors developed the techniques and technology needed for nonsurgical crossing from a donor (superior vena cava) to a recipient (PA) vessel and endovascular stent-based anastomosis of those blood vessels. The authors undertook this transcatheter approach for an adult with untreated congenital heart disease with severe cyanosis and significant surgical risk. They rehearsed the procedure step by step using contrast-enhanced cardiac computed tomography and a patient-specific 3-dimensional printed heart model. RESULTS: The authors describe a first-in-human, fully percutaneous superior cavopulmonary anastomosis (bidirectional Glenn operation equivalent). The patient, a 35-year-old woman, was homebound due to dyspnea and worsening cyanosis. She was diagnosed with functional single ventricle and very limited pulmonary blood flow. The heart team believed surgical palliation conferred high operative risk due to the patient's complete condition. With the percutaneous procedure, the patient recovered uneventfully and remained improved clinically after 6 months. CONCLUSIONS: This procedure may provide a viable alternative to one of the foundational open-heart surgeries currently performed to treat single-ventricle congenital heart disease.

Cardiac magnetic resonance imaging after stage I Norwood operation for hypoplastic left heart syndrome.

BACKGROUND: After the Norwood operation, a patient's suitability for proceeding to a bidirectional cavopulmonary connection (BCPC) is assessed by a combination of echocardiography and diagnostic cardiac catheterization. In this study, we describe the results of 37 patients who underwent cardiovascular magnetic resonance (MR) assessment before BCPC. METHODS AND RESULTS: Cardiovascular MR and echocardiography were performed in 37 infants with hypoplastic left heart syndrome before BCPC, and the findings were compared with surgical findings. MR assessment of ventricular function and valvar regurgitation were compared with echocardiography. MR exhibited high sensitivity and specificity for identification of neoaortic (sensitivity 86%, specificity 97%) and left pulmonary artery (sensitivity 100%, specificity 94%) obstruction. Echocardiography exhibited poor sensitivity for identification of vascular stenosis. The mean right ventricular ejection fraction calculated from the MR data was 50+/-10%. There was general agreement between MR and echocardiographic measures of ventricular function, although patients with good function on echocardiography demonstrated a wide range of ejection fractions. There was good agreement between MR and echocardiography for identification of valvar regurgitation. CONCLUSIONS: Cardiovascular MR can be used to define ventricular and valvar function and vascular anatomy in infants with hypoplastic left heart syndrome after the Norwood operation. We have shown how this information can be used to plan the BCPC and identify any revisions or additional valvar surgery.