Computational framework for the generation of one-dimensional vascular models accounting for uncertainty in networks extracted from medical images.

One-dimensional (1D) cardiovascular models offer a non-invasive method to answer medical questions, including predictions of wave-reflection, shear stress, functional flow reserve, vascular resistance and compliance. This model type can predict patient-specific outcomes by solving 1D fluid dynamics equations in geometric networks extracted from medical images. However, the inherent uncertainty in in vivo imaging introduces variability in network size and vessel dimensions, affecting haemodynamic predictions. Understanding the influence of variation in image-derived properties is essential to assess the fidelity of model predictions. Numerous programs exist to render three-dimensional surfaces and construct vessel centrelines. Still, there is no exact way to generate vascular trees from the centrelines while accounting for uncertainty in data. This study introduces an innovative framework employing statistical change point analysis to generate labelled trees that encode vessel dimensions and their associated uncertainty from medical images. To test this framework, we explore the impact of uncertainty in 1D haemodynamic predictions in a systemic and pulmonary arterial network. Simulations explore haemodynamic variations resulting from changes in vessel dimensions and segmentation; the latter is achieved by analysing multiple segmentations of the same images. Results demonstrate the importance of accurately defining vessel radii and lengths when generating high-fidelity patient-specific haemodynamics models. KEY POINTS: This study introduces novel algorithms for generating labelled directed trees from medical images, focusing on accurate junction node placement and radius extraction using change points to provide haemodynamic predictions with uncertainty within expected measurement error. Geometric features, such as vessel dimension (length and radius) and network size, significantly impact pressure and flow predictions in both pulmonary and aortic arterial networks. Standardizing networks to a consistent number of vessels is crucial for meaningful comparisons and decreases haemodynamic uncertainty. Change points are valuable to understanding structural transitions in vascular data, providing an automated and efficient way to detect shifts in vessel characteristics and ensure reliable extraction of representative vessel radii.

Characterization and Z-score Calculation of Cardiac MRI parameters in patients after the Fontan operation. A Fontan Outcome Registry using CMR Examinations (FORCE) study.

BACKGROUND: Cardiac magnetic resonance (CMR) offers valuable hemodynamic insights post-Fontan, but is limited by the absence of normative single ventricle data. The Fontan Outcomes Registry using CMR Examinations (FORCE) is a large international Fontan-specific CMR registry. This study used FORCE registry data to evaluate expected CMR ventricular size/function and create Fontan-specific z-scores adjusting for ventricular morphology (VM) in healthier Fontan patients. METHODS: "Healthier" Fontan patients were defined as patients free of adverse outcomes, who are New York Heart Association Class I, have mild or less valve disease, and <30% aortopulmonary collateral burden. General linear modeling was performed on 70% of the dataset to create z-scores for volumes and function. Models were tested using the remainder (30%) of the data. The z-scores were compared between children and adults. The z-scores were also compared between "healthier" Fontan and patients with adverse outcomes (death, listing for transplantation or multiorgan disease). RESULTS: The "healthier" Fontan population included 885 patients (15.0 ± 7.6 years) from 18 institutions with 1,156 CMR examinations. Patients with left ventricle morphology had lower volume, mass and higher ejection fraction (EF) compared to right or mixed (two-ventricles) morphology (p<0.001 for all pairwise comparisons). Gender, BSA and VM were used in z-scores. Of the "healthier" Fontan patients, 647 were children <18 years and 238 were adults. Adults had lower ascending aorta flow (2.9 ± 0.7 vs 3.3 ± 0.8L/min/m2, p<0.001) and ascending aorta flow z-scores (-0.16 ± 1.23 vs 0.05 ± 0.95, 0.02) compared to children. Additionally, there were 1595 patients with adverse outcomes who were older (16.1 ± 9.3 vs 15.0 ± 7.6, p<0.001) and less likely to have LV morphology (35 vs 47%, p<0.001). Patients with adverse outcomes had higher z-scores for ventricular volume and mass and lower z-scores for EF and ascending aorta flow compared to the "healthier" Fontan cohort. CONCLUSION: This is the first study to generate CMR z-scores post-Fontan. Importantly the z-scores were generated and tested in "healthier" Fontan patients and both pediatric and adult Fontan patients. These equations may improve CMR-based risk stratification after the Fontan operation.

Mitral Annular Disjunction Associated with Ventricular Dilation in Pediatric Marfan Syndrome: A Cardiovascular Magnetic Resonance Study.

BACKGROUND: Mitral annular disjunction (MAD) has increasingly been recognized as a marker for adverse cardiovascular events in Marfan syndrome (MFS). As recent adult data links MFS with left ventricular (LV) dilation and reduced ejection fraction (LVEF), we hypothesized that MAD may be associated with LV dilation in pediatric MFS patients. METHODS: A retrospective analysis was performed among MFS patients < 19 years old at initial cardiac MRI (CMR). MAD and mitral valve prolapse (MVP) were assessed by CMR or most proximate echo. CMR-derived left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volumes were measured. Indexed volumes, absolute and indexed z-scores, and LVEF were calculated. The combined volume load from mitral and aortic regurgitation was indexed to LV stroke volume, allowing exclusion of patients with greater than mild volume load or prior MV intervention. MAD association with LV volumes and z-scores was then assessed. RESULTS: Forty-two patients were analyzed (median age 13.5 years old, IQR [10.9, 15.3]). MAD was present in 28 patients (66.7%), and MVP was present in 13 patients (31.0%). Absolute LVEDV z-score was > 2 in 35.7% of patients, LVESV z-score was > 2 in 42.9%, and LVEF was < 55% in 45.2%. In multivariable analysis including MVP, MAD remained independently associated with elevated absolute LVESV z-score > 2 (RR 3.88, 95% CI 1.02-14.69, p = 0.046). CONCLUSION: MAD was associated with CMR-derived volume-load-independent LV dilation among pediatric MFS patients. Prospective studies are needed to further understand this association and its relationship with LV dilation over time.

Abnormal Left Ventricular Strain Correlates with Left Ventricular Dysfunction but not Aortic Pathology in Marfan Syndrome in Children.

Cardiomyopathy is a complication in adults with Marfan syndrome (MFS). Early recognition of MFS patients at high risk of cardiomyopathy could impact monitoring and treatment. Abnormal ventricular strain has been associated with impaired ventricular function among adults with MFS but remains understudied in children. We retrospectively analyzed a cohort of patients with MFS undergoing cardiac magnetic resonance imaging (CMR) performed in 2003-2018 at age < 19 years. Correlations were evaluated between initial global circumferential strain (GCS) and global longitudinal strain (GLS) and the outcomes of left ventricular ejection fraction (LVEF), aortic root z-score, and vertebral artery tortuosity index corrected for height (VTI-h), all measured from CMR, using Spearman correlation. In those with serial CMR, the ability of ventricular strain to predict development of abnormal LVEF within a 5-year period was assessed. A total of 31 subjects were included (median age at initial CMR 13.5 years, Q1Q3 10.7-16.2 years), with 48% (n = 15) having LVEF < 55%. Worse GCS and worse GLS were associated with lower LVEF (ρ = - 0.629, p < 0.001 and ρ = - 0.411, p = 0.030, respectively). A clinical cutoff of GCS = - 34% predicted LVEF < 55% with sensitivity = 80% and specificity = 50%. Neither GCS nor GLS was associated with aortic root z-score (GCS: p = 0.524; GLS: p = 0.624) nor VTI-h (GCS: p = 0.949; GLS: p = 0.593). Of those with LVEF ≥ 55%, initial GCS and GLS did not differ between those with later normal versus abnormal LVEF (GCS: p = 0.505; GLS: p = 0.232). In this cohort, abnormal LV strain was associated with abnormal LVEF, but not with aortic dilation or low LVEF within the 5 years post-CMR.

Pre-Fontan Assessment Utilizing Combined Cardiac Catheterization and Cardiac MRI: Comparison to the Pre-Fontan Catheterization.

Single ventricle patients eligible for Fontan completion undergo pre-Fontan catheterization for hemodynamic and anatomic assessment prior to surgery. Cardiac magnetic resonance imaging may be used to evaluate pre-Fontan anatomy, physiology, and collateral burden. We describe our center's outcomes in patients undergoing pre-Fontan catheterization combined with cardiac magnetic resonance imaging. A retrospective review of patients undergoing pre-Fontan catheterization from 10/2018 to 04/2022 at Texas Children's Hospital was performed. Patients were divided into 2 groups: combined cardiac magnetic resonance imaging and catheterization (combined group) and those who underwent catheterization only (catheterization only group). There were 37 patients in the combined group and 40 in the catheterization only group. Both groups were similar in age and weight. Patients undergoing combined procedures received less contrast, and experienced less in-lab time, fluoroscopy time and catheterization procedure time. Median radiation exposure was lower in the combined procedure group but was not statistically significant. Intubation and total anesthesia times were higher in the combined procedure group. Patients undergoing a combined procedure were less likely to have collateral occlusion performed than in the catheterization only group. Bypass time, intensive care unit length of stay, and chest tube duration were similar in both groups at the time of Fontan completion. Combined pre-Fontan assessment decreases catheterization procedure and fluoroscopy time associated with cardiac catheterization at the expense of longer anesthetic times, and results in similar Fontan outcomes compared to when cardiac catheterization alone is utilized.

Evaluating perinatal and neonatal outcomes among children with vascular Ehlers-Danlos syndrome.

PURPOSE: Birth outcomes data for patients with vascular Ehlers-Danlos syndrome (VEDS) are limited. METHODS: Patients with a pathogenic or likely pathogenic COL3A1 variant were included. Outcomes included gestational age (GA), birthweight (BW), and maternal complications. Birth outcomes were first compared with that of US population data, then compared by sex, maternal affected status, and COL3A1 genotype. RESULTS: A total of 41 children were included (70.7% male), including 32 with high-risk (missense and splice site) variants. Preterm birth (<37 weeks) was more common in patients with VEDS than in the US population (48.8% vs 12.2%, P < .0001). Low BW (<2.5 kg) was also more common in patients with VEDS than in the US population (P < .0001), although, it was appropriate after GA adjustment (median GA-adjusted z-score 0.01 vs z-score 0.0, P = .26). No differences in GA or BW were observed by sex or maternal affected status. Those with high-risk variants were more likely to be born preterm than those with haploinsufficient variants, although this did not meet significance criteria (53% vs 33%, P = .35). Of the 6 affected mothers, 5 had perinatal complications. CONCLUSION: Preterm birth is more common in children with VEDS than in the general population. Maternal affected status is not associated with preterm birth, suggesting that risk is conferred by the fetal VEDS diagnosis alone.

The frequency and efficacy of genetic testing in individuals with scimitar syndrome.

BACKGROUND: Scimitar syndrome is a rare CHD composed of partial anomalous pulmonary venous connection from the right lung, via a scimitar vein, to the inferior vena cava rather than the left atrium. Genetic conditions associated with scimitar syndrome have not been well investigated at present. METHODS: Our study included patients with scimitar syndrome diagnosed at Texas Children's Hospital from January 1987 to July 2020. Medical records were evaluated to determine if genetic testing was performed, including chromosomal microarray analysis or whole-exome sequencing. Copy number variants identified as pathogenic/likely pathogenic and variants of unknown significance were collected. Analyses of cardiac and extracardiac findings were performed via chart review. RESULTS: Ninety-eight patients were identified with scimitar syndrome, 89 of which met inclusion criteria. A chromosome analysis or chromosomal microarray analysis was performed in 18 patients (20%). Whole-exome sequencing was performed in six patients following negative chromosomal microarray analysis testing. A molecular genetic diagnosis was made in 7 of 18 cases (39% of those tested). Ninety-six per cent of the cohort had some type of extracardiac finding, with 43% having asthma and 20% having a gastrointestinal pathology. Of the seven patients with positive genetic testing, all had extracardiac anomalies with all but one having gastrointestinal findings and 30% having congenital diaphragmatic hernia. CONCLUSIONS: Genetic testing revealed an underlying diagnosis in roughly 40% of those tested. Given the relatively high prevalence of pathogenic variants, we recommend chromosomal microarray analysis and whole-exome sequencing for patients with scimitar syndrome and extracardiac defects.

Validation of Right Atrial Area as a Measure of Right Atrial Size and Normal Values of in Healthy Pediatric Population by Two-Dimensional Echocardiography.

Right atrial (RA) size is a prognostic indicator for heart failure and cardiovascular death in adults. Data regarding use of RA area (RAA) by two-dimensional echocardiography as a surrogate for RA size and allometric modeling to define appropriate indexing of the RAA are lacking. Our objective was to validate RAA as a reliable measure of RA size and to define normal reference values by transthoracic echocardiography (TTE) in a large population of healthy children and develop Z-scores using a validated allometric model for indexing RAA independent of age, sex, and body size. Agreement between RAA and volume by 2D, 3D TTE, and MRI was assessed. RAA not volume by 2D TTE is an excellent surrogate for RA size. RAA/BSA1 has an inverse correlation with BSA with a residual relationship to BSA (r = - 0.54, p < 0.0001). The allometric exponent (AE) derived for the entire cohort (0.85) also fails to eliminate the residual relationship. The entire cohort divided into two groups with a BSA cut-off of 1 m2 to provide the best-fit allometric model (r = 0). The AE by least square regression analysis for each group is 0.95 and 0.88 for BSA < 1 m2 and > 1 m2, respectively, and was validated against an independent sample. The mean indexed RAA ± SD for BSA ≤ 1 m2 and > 1 m2 is 9.7 ± 1.3 cm2 and 8.7 ± 1.3 cm2, respectively, and was used to derive Z-scores. RAA by 2D TTE is superior to 2D or 3D echocardiography-derived RA volume as a measure of RA size using CMR as the reference standard. RAA when indexed to BSA1, decreases as body size increases. The best-fit allometric modeling is used to create Z scores. RAA/BSA0.95 for BSA < 1 m2 and RAA/BSA0.88 for those with BSA > 1 m2 can be used to derive Z scores.

Transseptal puncture using surgical electrocautery in children and adults with and without complex congenital heart disease.

BACKGROUND: Atrial transseptal puncture (TSP) for cardiac catheterization procedures remain challenging in children and adults with complex congenital heart disease (CHD). OBJECTIVES: We sought to evaluate our experience using radiofrequency (RF) current via surgical electrocautery needle for TSP to facilitate diagnostic and interventional procedures. METHODS: Retrospective chart review of all patients (pts) who underwent TSP using RF energy (10-25 W) via surgical electrocautery from three centers from January 2011 to January 2017 were evaluated. Echocardiograms were reviewed to define the atrial septum as normal and complex (thin aneurysmal, thick/fibrotic, synthetic patch material, and extra cardiac conduit). RESULTS: A total of 54 pts underwent 55 successful TSP. Median age was 12.5 years (1 day-54 years) and weight was 52.7 kg (2-162). Indications for TSP included; EP study and ablation procedures in structurally normal hearts (n = 24) and in complex atrial septum/CHD and structural heart disease pts (n = 30): Electrophysiology study and ablation in 4, diagnostic catheterization in 9, and interventional procedures in 17 pts were performed. Atrial TSP was successful in 54/55 (98%). Atrial perforation with tiny-small pericardial effusion not requiring intervention was noted in 2 pts. TSP was unsuccessful in one critically ill neonate with unobstructed TAPVR and restricted atrial septum who experienced cardiac arrest requiring CPR, ECMO, and emergent surgery. CONCLUSIONS: RF current delivery using surgical electrocautery for TSP is a feasible and an effective option in patients with complex CHD for diagnostic, interventional, and electrophysiology procedures.

Feature Tracking-Derived Peak Systolic Strain Compared to Late Gadolinium Enhancement in Troponin-Positive Myocarditis: A Case-Control Study.

Cardiac magnetic resonance (CMR) assesses myocardial involvement in myocarditis (MYO). Current techniques are qualitative, subjective, and prone to interpretation error. Feature tracking (FT) analyzes myocardial strain using CMR and has not been examined in MYO. We hypothesize that regional left ventricular (LV) strain is abnormal in MYO. Regional strain by FT was compared to late gadolinium enhancement (LGE) and troponin leak as measures of myocardial involvement. This single-center, retrospective CMR study reviewed patients with clinical MYO and structurally normal hearts who underwent CMR at our institution. Young adults with normal cardiac anatomy, function, and absent LGE served as controls. MYO patients with documented troponin leak and normal global ejection fraction (EF > 50 %) were included in comparison. FT determined regional myocardial peak systolic strain (pkS) in longitudinal and circumferential distributions. T tests compared strain values between cases and controls. Receiver operating characteristic curves determined pkS values with highest sensitivity and specificity for concurrent troponin leak and LGE. FT was performed on 57 patients: 37 MYO and 20 controls. Twenty-eight cases with normal EF, and 20 control patients were included in final analysis. Nearly all cases with normal function demonstrated abnormal regional pkS (27/28, 96 %). Cases had significantly diminished pkS when compared to controls in all regions except the longitudinal 2C distribution. FT-derived longitudinal and circumferential pkS is sensitive and specific in identifying myocardial involvement, namely the presence of troponin leak and LGE. FT may be a useful adjunctive, objective measure of myocardial involvement in patients with MYO and normal LV function.

Repair of anomalous left coronary artery from the pulmonary artery in the modern era: preoperative predictors of immediate postoperative outcomes and long term cardiac follow-up.

Little is known about preoperative factors affecting postoperative morbidity following anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) repair. This study aimed at identifying predictors of postoperative outcomes, including mortality and left ventricle (LV) normalization. A retrospective, single institution review was conducted on forty-four ALCAPA repairs from April 1991 to November 2012. Preoperative clinical data and echocardiograms were analyzed. Postoperative outcomes included duration of intensive care supports and mortality. Time to normalization of LV end diastolic dimension (LVEDD) and function were assessed. Logistic regression and Cox proportional hazard analyses were used to correlate preoperative variables to postoperative outcomes. Forty-four patients underwent ALCAPA repair. No in-hospital or late mortality was observed. LVEDD, weight, and LV shortening fraction (SF) independently predicted duration of postoperative inotropic support. LVEDD and body surface area independently predicted the duration of postoperative intubation. For the infant majority, younger age predicted longer duration of postoperative intubation (p = 0.048) and LVEDD Z-score independently predicted duration of postoperative IV inotropic support (p = 0.042). LV function normalized in all patients for whom follow-up data was available. LVEDD Z-score independently predicted time to normalization of LV function (p = 0.013). ALCAPA repair in the current era has excellent outcomes, with no mortality in our cohort. Immediate postoperative morbidities are influenced by patient size, LVEDD, and preoperative SF. Outcomes of infantile ALCAPA are influenced by the degree of LV dilation. Time to normalization of LV function is related to LVEDD. Limitations included retrospective evaluation of LV function.

Two-dimensional speckle-tracking-derived segmental peak systolic longitudinal strain identifies regional myocardial involvement in patients with myocarditis and normal global left ventricular systolic function.

The presence of myocardial late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) imaging in concert with electrocardiography and elevated biomarkers helps support the diagnosis of acute myocarditis. Two-dimensional echocardiography is limited to global and qualitative regional function assessment and may not contribute to the diagnosis, especially in the presence of normal LV systolic function. Two-dimensional speckle-tracking (2D-STE)-derived segmental peak systolic (pkS) longitudinal strain (LS) may identify segmental myocardial involvement in myocarditis. We sought to identify an association between segmental pkS, LGE, and troponin levels in patients with myocarditis. Retrospective analysis of myocardial segmental function by 2D-STE segmental strain was compared to the presence of LGE and admission peak troponin levels in patients with acute myocarditis and preserved global LV systolic function. American Heart Association 17-segment model was used for comparison between imaging modalities. Global function was assessed by m-mode-derived shortening fraction (SF). Descriptive statistics and regression analysis were utilized. Forty-four CMRs performed to evaluate for myocarditis were identified. Of the 44, 10 patients, median age 17.5 years (14-18.5 years) and median SF 35 % (28-44 %), had paired CMR and 2D-STE data for analysis, and 161/170 segments could be analyzed by both methods for comparison. PkS LS was decreased in 51 % of segments that were positive for LGE with average pkS of -14.7 %. Segmental pkS LS abnormalities were present in all but one patient who had abnormal pkS circumferential strain. Global pkS LS was decreased in patients with myocarditis. There is a moderate correlation between decreased pkS LS and the presence of LGE by CMR, 2D-STE for myocardial involvement in acute myocarditis can serve as an useful noninvasive adjunct to the existing tests used for the diagnosis of acute myocarditis and might have a role in prognostication.

Evidence of cardiomyopathy associated with Marfan syndrome in children.

OBJECTIVE: Marfan syndrome (MFS)-associated cardiomyopathy, defined as ventricular dilation and dysfunction unexplained by volume loading, is not well defined in children. This study evaluated ventricular size and function in paediatric MFS using cardiac MRI (cMRI). METHODS: This retrospective cohort study examined patients with MFS <19 years old at first cMRI. Left ventricular (LV) ejection fraction (EF) <55% was considered abnormal, as were z-scores >2. Combined mitral and aortic regurgitation indexed to LV stroke volume <20% defined absent/mild volume load. Biventricular volumes and EF on serial cMRI studies were compared with normative paediatric cMRI values, with measures converted to z-scores as appropriate. Longitudinal changes in volumes and EF were evaluated by mixed linear regression. Associations between ventricular, aortic and mitral characteristics were evaluated. RESULTS: 58 patients (60% male) were evaluated. Median age at initial cMRI was 13.6 years (IQR 10.0-15.8 years). Among patients with absent/mild LV volume load at initial cMRI (n=44, 76%), indexed LV end-diastolic volume (EDV) was significantly increased above normative values (median z-score 1.8, IQR 0.6-3.5, p<0.0001) and LVEF was abnormal in 48% (21/44). In the absence of volume loading, mitral valve prolapse (MVP) was associated with larger ventricular volumes and lower LVEF. Among those with serial cMRIs, LVEF and EDV z-scores did not significantly change over a mean follow-up time between cMRI studies of 1.5 years. CONCLUSION: Ventricular dilation and reduced EF are common in children with MFS and occur with no/mild LV volume load, suggesting intrinsic cardiomyopathy. MVP may be associated with cardiomyopathy.

Genetic Testing for Supravalvar Aortic Stenosis: What to Do When It Is Not Williams Syndrome.

BACKGROUND: We aimed to describe the frequency and yield of genetic testing in supravalvar aortic stenosis (SVAS) following negative evaluation for Williams-Beuren syndrome (WS). METHODS AND RESULTS: This retrospective cohort study included patients with SVAS at our institution who had a negative evaluation for WS from May 1991 to September 2021. SVAS was defined as (1) peak supravalvar velocity of ≥2 meters/second, (2) sinotubular junction or ascending aortic Z score <-2.0, or (3) sinotubular junction Z score <-1.5 with family history of SVAS. Patients with complex congenital heart disease, aortic valve disease as the primary condition, or only postoperative SVAS were excluded. Genetic testing and diagnoses were reported. Of 162 patients who were WS negative meeting inclusion criteria, 61 had genetic testing results available (38%). Chromosomal microarray had been performed in 44 of 61 and was nondiagnostic for non-WS causes of SVAS. Sequencing of 1 or more genes was performed in 47 of 61. Of these, 39 of 47 underwent ELN sequencing, 20 of 39 (51%) of whom had a diagnostic variant. Other diagnoses made by gene sequencing were Noonan syndrome (3 PTPN11, 1 RIT1), Alagille syndrome (3 JAG1), neurofibromatosis (1 NF1), and homozygous familial hypercholesterolemia (1 LDLR1). Overall, sequencing was diagnostic in 29 of 47 (62%). CONCLUSIONS: When WS is excluded, gene sequencing for SVAS is high yield, with the highest yield for the ELN gene. Therefore, we recommend gene sequencing using a multigene panel or exome analysis. Hypercholesterolemia can also be considered in individuals bearing the stigmata of this disease.

Cardiac MRI Predictors of Arrhythmic Sudden Cardiac Events in Patients With Fontan Circulation.

BACKGROUND: Among patients with congenital heart disease, those with single ventricles have the highest risk of early mortality. Sudden cardiac death is an important cause of death in this population. Understanding the risk factors for sudden cardiac events (SCE) in Fontan patients could improve prediction and prevention. OBJECTIVES: The goal of this study was to determine the prevalence of SCE and risk factors for SCE in the Fontan population. METHODS: The Fontan Outcomes Registry Using CMR Examinations (FORCE) is an international registry collecting clinical and imaging data on Fontan patients. SCE was defined as: 1) cardiac arrest from a shockable rhythm; 2) need for emergent cardioversion/defibrillation; or 3) documented sustained ventricular tachycardia. Univariate and multivariate Cox proportional hazards regression models estimated hazard ratios for predictors of SCE. RESULTS: Our sample included 3,132 patients (41% female). The median age at first cardiac magnetic resonance was 14.6 years. SCE was experienced by 3.5% (n = 109) over a median follow-up time of 4.00 years. Of the 109 patients with SCE, 39 (36%) died. On multivariable analysis, NYHA functional class >II (HR: 4.91; P < 0.0001), history of protein-losing enteropathy/plastic bronchitis (HR: 2.37; P = 0.0082), single-ventricle end-diastolic volume index >104 mL/m2 (HR: 3.15; P < 0.0001), and ejection fraction <50% (HR: 1.73; P = 0.0437) were associated with SCE. Kaplan-Meier analysis demonstrated that in patients with none of the above risk factors, the 4-year freedom from SCE was 99.5%. CONCLUSIONS: SCE occurred in 3.5% of the study population, and one-third of patients who experienced SCE died. Mild ventricular dysfunction and dilatation by cardiac magnetic resonance, NYHA functional class, and history of protein-losing enteropathy/plastic bronchitis were associated with SCE.

High-Performing Fontan Patients: A Fontan Outcome Registry by Cardiac Magnetic Resonance Imaging Study.

Background: Fontan patients exhibit decreased exercise capacity. However, there is a subset of high-performing Fontan (HPF) patients with excellent exercise capacity. Objectives: This study aims to: 1) create a Fontan-specific percent predicted peak VO2 tool using exercise data; 2) examine clinical factors associated with HPF patients; and 3) examine late outcomes in HPF patients. Methods: Patients in the multi-institutional Fontan Outcomes Registry Using CMR Examination above the age of 8 years who had a maximal exercise test were included. An HPF patient was defined as a patient in the upper Fontan-specific percent predicted peak VO2 quartile. Multivariable logistic regression was employed to investigate factors associated with the HPF and Cox regression was used to examine the association between HPF patients and late outcomes (composite of death or listing for cardiac transplant). Results: The study included 813 patients (mean age: 20.2 ± 8.7 years). An HPF patient was associated with left ventricular morphology (OR: 1.50, P = 0.04), mixed morphology (OR: 2.23, P < 0.001), and a higher ejection fraction (OR: 1.31 for 10% increase, P = 0.01). Patients with at least moderate atrioventricular valve regurgitation, protein-losing enteropathy, or who were using psychiatric medications, were less likely to be an HPF patient. After a mean follow-up of 3.7 years, 46 (5.7%) patients developed a composite endpoint. HPF had a lower risk of death or listing for cardiac transplant (HR: 0.06 [95% CI: 0.01-0.25]). Conclusions: Patients with HPF have more favorable outcomes when compared to patients with lower exercise capacity. This large registry data highlights the role of exercise testing in providing personalized care and surveillance post-Fontan.

Mitral annular disjunction and its progression during childhood in Marfan syndrome.

AIMS: Data on mitral annular disjunction (MAD) in children with Marfan syndrome (MFS) are sparse. To investigate the diagnostic yield of MAD by echocardiography and cardiac magnetic resonance imaging (CMR), its prevalence and progression during childhood. METHODS AND RESULTS: We included patients <21 years old with MFS, defined by 2010 Ghent criteria and a pathogenic FBN1 variant or ectopia lentis. Two readers measured systolic separation between the mitral valve (MV) posterior hinge point and left ventricular (LV) myocardium on initial and subsequent imaging. MAD was defined as MV-LV separation ≥2 mm, MV prolapse (MVP) as atrial displacement ≥2 mm. Kappa coefficients evaluated echocardiogram-CMR agreement. Bland-Altman and intraclass correlation coefficients (ICCs) assessed inter-rater and inter-modality reliability. Univariable mixed-effects linear regression was used to evaluate longitudinal changes of MAD. MAD was detected in 60% (110/185) eligible patients. MVP was present in 48% (53/110) of MAD and MAD in 90% (53/59) of MVP. MAD detection by CMR and echocardiography had 96% overall agreement (Kappa = 0.89, P < 0.001) and a 0.32 mm estimate bias (95% CI 0.00, 0.65). ICC by echocardiography, CMR, and between modalities were 0.97 (95% CI 0.93, 0.98), 0.92 (95% CI 0.79, 0.97), and 0.91 (95% CI 0.85, 0.94), respectively. MAD was associated with aortic root dilation (P < 0.001). MAD was found in children of all ages, increased +0.18 mm/year (95% CI +0.14, +0.22) during a median duration of 5.5 years (IQR 3.1, 7.5 years). MAD indexed by height yielded a constant value +0.0002 mm/m/year (95% CI -0.0002, +0.0005 mm/m/year). CONCLUSION: MAD was common in pediatric MFS and was associated with aortic root dilation. MAD detection by echocardiography and CMR was highly reliable, suggesting that routine assessment in MFS is feasible. MAD was present in neonates and progressed over time but remained constant when indexing by height. Further studies are needed to evaluate MAD as a biomarker for clinical outcomes in pediatric MFS.

Computational framework for the generation of one-dimensional vascular models accounting for uncertainty in networks extracted from medical images.

One-dimensional (1D) cardiovascular models offer a non-invasive method to answer medical questions, including predictions of wave-reflection, shear stress, functional flow reserve, vascular resistance, and compliance. This model type can predict patient-specific outcomes by solving 1D fluid dynamics equations in geometric networks extracted from medical images. However, the inherent uncertainty in in-vivo imaging introduces variability in network size and vessel dimensions, affecting hemodynamic predictions. Understanding the influence of variation in image-derived properties is essential to assess the fidelity of model predictions. Numerous programs exist to render three-dimensional surfaces and construct vessel centerlines. Still, there is no exact way to generate vascular trees from the centerlines while accounting for uncertainty in data. This study introduces an innovative framework employing statistical change point analysis to generate labeled trees that encode vessel dimensions and their associated uncertainty from medical images. To test this framework, we explore the impact of uncertainty in 1D hemodynamic predictions in a systemic and pulmonary arterial network. Simulations explore hemodynamic variations resulting from changes in vessel dimensions and segmentation; the latter is achieved by analyzing multiple segmentations of the same images. Results demonstrate the importance of accurately defining vessel radii and lengths when generating high-fidelity patient-specific hemodynamics models.

A Deep Learning Pipeline for Assessing Ventricular Volumes from a Cardiac MRI Registry of Patients with Single Ventricle Physiology.

Purpose To develop an end-to-end deep learning (DL) pipeline for automated ventricular segmentation of cardiac MRI data from a multicenter registry of patients with Fontan circulation (Fontan Outcomes Registry Using CMR Examinations [FORCE]). Materials and Methods This retrospective study used 250 cardiac MRI examinations (November 2007-December 2022) from 13 institutions for training, validation, and testing. The pipeline contained three DL models: a classifier to identify short-axis cine stacks and two U-Net 3+ models for image cropping and segmentation. The automated segmentations were evaluated on the test set (n = 50) by using the Dice score. Volumetric and functional metrics derived from DL and ground truth manual segmentations were compared using Bland-Altman and intraclass correlation analysis. The pipeline was further qualitatively evaluated on 475 unseen examinations. Results There were acceptable limits of agreement (LOA) and minimal biases between the ground truth and DL end-diastolic volume (EDV) (bias: -0.6 mL/m2, LOA: -20.6 to 19.5 mL/m2) and end-systolic volume (ESV) (bias: -1.1 mL/m2, LOA: -18.1 to 15.9 mL/m2), with high intraclass correlation coefficients (ICCs > 0.97) and Dice scores (EDV, 0.91 and ESV, 0.86). There was moderate agreement for ventricular mass (bias: -1.9 g/m2, LOA: -17.3 to 13.5 g/m2) and an ICC of 0.94. There was also acceptable agreement for stroke volume (bias: 0.6 mL/m2, LOA: -17.2 to 18.3 mL/m2) and ejection fraction (bias: 0.6%, LOA: -12.2% to 13.4%), with high ICCs (>0.81). The pipeline achieved satisfactory segmentation in 68% of the 475 unseen examinations, while 26% needed minor adjustments, 5% needed major adjustments, and in 0.4%, the cropping model failed. Conclusion The DL pipeline can provide fast standardized segmentation for patients with single ventricle physiology across multiple centers. This pipeline can be applied to all cardiac MRI examinations in the FORCE registry. Keywords: Cardiac, Adults and Pediatrics, MR Imaging, Congenital, Volume Analysis, Segmentation, Quantification Supplemental material is available for this article. © RSNA, 2023.

A computational study of aortic reconstruction in single ventricle patients.

Patients with hypoplastic left heart syndrome (HLHS) are born with an underdeveloped left heart. They typically receive a sequence of surgeries that result in a single ventricle physiology called the Fontan circulation. While these patients usually survive into early adulthood, they are at risk for medical complications, partially due to their lower than normal cardiac output, which leads to insufficient cerebral and gut perfusion. While clinical imaging data can provide detailed insight into cardiovascular function within the imaged region, it is difficult to use these data for assessing deficiencies in the rest of the body and for deriving blood pressure dynamics. Data from patients used in this paper include three-dimensional, magnetic resonance angiograms (MRA), time-resolved phase contrast cardiac magnetic resonance images (4D-MRI) and sphygmomanometer blood pressure measurements. The 4D-MRI images provide detailed insight into velocity and flow in vessels within the imaged region, but they cannot predict flow in the rest of the body, nor do they provide values of blood pressure. To remedy these limitations, this study combines the MRA, 4D-MRI, and pressure data with 1D fluid dynamics models to predict hemodynamics in the major systemic arteries, including the cerebral and gut vasculature. A specific focus is placed on studying the impact of aortic reconstruction occurring during the first surgery that results in abnormal vessel morphology. To study these effects, we compare simulations for an HLHS patient with simulations for a matched control patient that has double outlet right ventricle (DORV) physiology with a native aorta. Our results show that the HLHS patient has hypertensive pressures in the brain as well as reduced flow to the gut. Wave intensity analysis suggests that the HLHS patient has irregular circulatory function during light upright exercise conditions and that predicted wall shear stresses are lower than normal, suggesting the HLHS patient may have hypertension.