Cardiac MRI evaluation of aortic biophysical properties in paediatric Turner syndrome.

BACKGROUND: Aortopathy in Turner syndrome is associated with aortic dilation, and the risk of dissection is increased when the aortic size index is ≥ 2-2.5 cm/m2. We evaluated the aortic biophysical properties in paediatric Turner syndrome using cardiac MRI to determine their relationship to aortic size index. METHODS: Turner syndrome patients underwent cardiac MRI to evaluate ventricular function, aortic dimensions, and biophysical properties (aortic stiffness index, compliance, distensibility, pulse wave velocity, and aortic and left ventricular elastance). Spearman correlation examined correlations between these properties and aortic size index. Data was compared to 10 controls. RESULTS: Of 25 Turner syndrome patients, median age 14.7 years (interquartile range: 11.0-16.8), height z score -2.7 (interquartile range: -2.92 - -1.54), 24% had a bicuspid aortic valve. Turner syndrome had increased diastolic blood pressure (p < 0.001) and decreased left ventricular end-diastolic (p < 0.001) and end-systolic (p = 0.002) volumes compared to controls. Median aortic size index was 1.81 cm/m2 (interquartile range: 1.45-2.1) and 7 had an aortic size index > 2 cm/m2. Aortic and left ventricular elastance were greater in Turner syndrome compared to controls (both p < 0.001). Increased aortic size index correlated with increased aortic elastance (r = 0.5, p = 0.01) and left ventricular elastance (r = 0.59, p = 0.002) but not aortic compliance. Higher ascending aortic areas were associated with increased aortic compliance (r = 0.44, p = 0.03) and left ventricular elastance (r = 0.49, p = 0.01). CONCLUSION: Paediatric Turner syndrome with similar aortic size index to controls showed MRI evidence of abnormal aortic biophysical properties. These findings point to an underlying aortopathy and provide additional parameters that may aid in determining risk factors for aortic dissection.

Adherence to clinical practice guidelines for pulmonary valve intervention after tetralogy of Fallot repair: A nationwide cohort study.

Objectives: To determine guideline adherence pertaining to pulmonary valve replacement (PVR) referral after tetralogy of Fallot (TOF) repair. Methods: Children and adults with cardiovascular magnetic resonance imaging scans and at least moderate pulmonary regurgitation were prospectively enrolled in the Comprehensive Outcomes Registry Late After TOF Repair (CORRELATE). Individuals with previous PVR were excluded. Patients were classified according to presence (+) versus absence (-) of PVR and presence (+) versus absence (-) of contemporaneous guideline satisfaction. A validated score (specific activity scale [SAS]) classified adult symptom status. Results: In total, 498 participants (57% male, mean age 32 ± 14 years) were enrolled from 14 Canadian centers (2013-2020). Mean follow-up was 3.8 ± 1.8 years. Guideline criteria for PVR were satisfied for the majority (n = 422/498, 85%), although referral for PVR occurred only in a minority (n = 167/498, 34%). At PVR referral, most were asymptomatic (75% in SAS class 1). One participant (0.6%) received PVR without meeting criteria (PVR+/indication-). The remainder (n = 75/498, 15%) did not meet criteria for and did not receive PVR (PVR-/indication-). Abnormal cardiovascular imaging was the most commonly cited indication for PVR (n = 61/123, 50%). The SAS class and ratio of right to left end-diastolic volumes were independent predictors of PVR in a multivariable analysis (hazard ratio, 3.33; 95% confidence interval, 1.92-5.8, P < .0001; hazard ratio, 2.78; 95% confidence interval, 2.18-3.55, P < .0001). Conclusions: Although a majority of patients met guideline criteria for PVR, only a minority were referred for intervention. Abnormal cardiovascular imaging was the most common indication for referral. Further research will be necessary to establish the longer-term clinical impact of varying PVR referral strategies.

Regional Elevation of Liver T1 in Fontan Patients.

Background: Fontan-associated liver disease (FALD) is characterized by hepatic congestion and progressive hepatic fibrosis in patients with the Fontan operation. This condition is generally clinically silent until late, necessitating techniques for early detection. Liver T1 mapping has been used to screen for FALD, but without consideration of regional variations in T1 values. Methods: Liver T1 measured with a liver-specific T1 mapping sequence (PROFIT1) in Fontan patients was compared with cohorts of patients with biventricular congenital heart disease (BiV-CHD) and controls with normal cardiac function and anatomy. Results: Liver T1 was significantly elevated in the Fontan cohort (n = 20) compared with patients with BiV-CHD (n = 12) and controls (n = 9) (781, 678, and 675 milliseconds, respectively; P < 0.001), with a consistent pattern of significantly elevated T1 values in the peripheral compared with central liver regions (ΔT1 = 54, 2, and 11 milliseconds; P < 0.001). PROFIT1 also yielded simultaneous T2∗ maps and fat fraction values that were similar in all groups. Fontan liver T1 values were also significantly elevated as compared with BiV-CHD and controls as measured with the cardiac (modified Look-Locker inversion) acquisitions (728, 583, and 583 milliseconds, respectively; P < 0.001) and values correlated with PROFIT1 liver T1 (R = 0.87, P < 0.001). Conclusions: Fontan patients have globally increased liver T1 values and consistent spatial variations, with higher values in the peripheral liver regions as compared with spatially uniform values in BiV-CHD and controls. The spatial patterns may provide insight into the progression of FALD. Liver T1 mapping studies should include uniform spatial coverage to avoid bias based on slice locations in this population.

Contexte: L'hépatopathie associée à une intervention de Fontan (FALD, pour Fontan-associated liver disease) se caractérise par une congestion hépatique et une fibrose hépatique évolutive chez les patients qui ont subi une intervention de Fontan. Il s'agit d'un état pathologique silencieux en début de progression, pour lequel des techniques de détection précoce sont requises. La cartographie T1 du foie est utilisée pour le dépistage de la FALD, mais sans que les variations locales des valeurs obtenues soient prises en compte. Méthodologie: Des valeurs T1 hépatiques ont été mesurées avec une séquence cartographique conçue pour le foie (PROFIT1) chez des patients qui ont subi une intervention de Fontan. Ces valeurs ont été comparées à celles d'une cohorte de patients atteints de cardiopathie congénitale biventriculaire (CC-BiV) et à celles de témoins dont l'anatomie et la fonction cardiaques étaient normales. Résultats: Les valeurs T1 hépatiques étaient significativement plus élevées chez les patients ayant subi une intervention de Fontan (n = 20) que chez les patients atteints de CC-BiV (n = 12) et chez les témoins (n = 9) (781 ms, 678 ms, 675 ms, p < 0,001), et ces valeurs tendaient à être plus élevées dans les régions périphériques que dans les régions centrales du foie (ΔT1 = 54 ms, 2 ms, 11 ms, p < 0,001). La séquence PROFIT1 a aussi permis l'obtention des valeurs de cartographie T2∗ et de teneur en matières grasses dans le foie, et ces valeurs étaient comparables pour tous les groupes. L'utilisation d'une séquence cardiaque (MOLLI, pour modified Lock-Locker inversion) a également engendré des valeurs T1 hépatiques significativement plus élevées chez les patients ayant subi l'intervention de Fontan que chez les patients atteints de CC-BiV et les témoins (728 ms, 583 ms, 583 ms, p < 0,001). Ces valeurs étaient par ailleurs corrélées avec les valeurs T1 hépatiques obtenues par la séquence PROFIT1 (R = 0,87, p < 0,001). Conclusions: Dans l'ensemble, les patients ayant subi l'intervention de Fontan présentaient des valeurs T1 hépatiques élevées accompagnées de variations spatiales. Les valeurs périphériques étaient systématiquement plus élevées, tandis que celles obtenues chez les patients atteints de CC-BiV et chez les témoins étaient uniformes. Les tendances qui sous-tendent ces variations spatiales pourraient fournir des pistes pour mieux comprendre la progression de la FALD. Enfin, les études de cartographie T1 hépatiques dans cette population devraient couvrir uniformément le foie pour éviter les biais liés à la coupe.

Multicenter research priorities in pediatric CMR: results of a collaborative wiki survey.

Multicenter studies in pediatric cardiovascular magnetic resonance (CMR) improve statistical power and generalizability. However, a structured process for identifying important research topics has not been developed. We aimed to (1) develop a list of high priority knowledge gaps, and (2) pilot the use of a wiki survey to collect a large group of responses. Knowledge gaps were defined as areas that have been either unexplored or under-explored in the research literature. High priority goals were: (1) feasible and answerable from a multicenter research study, and (2) had potential for high impact on the field of pediatric CMR. Seed ideas were contributed by a working group and imported into a pairwise wiki survey format which allows for new ideas to be uploaded and voted upon ( https://allourideas.org ). Knowledge gaps were classified into 2 categories: 'Clinical CMR Practice' (16 ideas) and 'Disease Specific Research' (22 ideas). Over a 2-month period, 3,658 votes were cast by 96 users, and 2 new ideas were introduced. The 3 highest scoring sub-topics were myocardial disorders (9 ideas), translating new technology & techniques into clinical practice (7 ideas), and normal reference values (5 ideas). The highest priority gaps reflected strengths of CMR (e.g., myocardial tissue characterization; implementation of technologic advances into clinical practice), and deficiencies in pediatrics (e.g., data on normal reference values). The wiki survey format was effective and easy to implement, and could be used for future surveys.

Patient-Reported Outcomes After Tetralogy of Fallot Repair.

BACKGROUND: Comprehensive assessment of tetralogy of Fallot (TOF) outcomes extends beyond morbidity and mortality to incorporate patient-reported outcomes (PROs), including quality of life (QOL) and health status (HS). OBJECTIVES: This study explored PROs in adolescents and adults with TOF and delineated variables associated with PROs. METHODS: This was a cross-sectional observational study within a larger prospective registry of adolescents and adults with repaired TOF and moderate or greater pulmonary regurgitation from North America, Europe, and Asia. Participants completed PROs, including a QOL linear analogue scale (QOL-LAS) and an HS visual analogue scale (HS-VAS). Scores were classified according to age cohorts: <18, 18 to 25, 26 to 40, and >40 years. RESULTS: The study included 607 patients (46.3% female; median age 28.5 years). Median QOL-LAS scores (0-100) were similar across age cohorts (85, 80, 80, 80; P = 0.056). Median HS-VAS scores (0-100) were lowest for the oldest cohort (77) compared with the 3 younger cohorts (85, 80, 80) (P = 0.004). With advancing age, there were increased reports of poor mobility (P < 0.001) and pain or discomfort (P = 0.004); problems in these dimensions were reported by 19.1% and 37.2% of patients aged >40 years, respectively. Of factors associated with superior PROs on multivariable regression modeling (ie, being White, being nonsyndromic, having employment, and having better left ventricular function; P < 0.05), asymptomatic status (functional class I) was the variable associated with the greatest number of QOL and HS measures (P < 0.001). CONCLUSIONS: Strategies to improve TOF outcomes should consider PROs alongside conventional clinical variables. Factors associated with poorer PROs represent opportunities to intervene to improve the lives of patients with TOF.

Implementation of Virtual Fontan Heart Camps During a Pandemic.

BACKGROUND: Children with a Fontan operation represent a unique form of congenital heart disease (CHD) that requires multiple cardiac surgeries and procedures with an uncertain long-term outcome. Given the rarity of the types of CHD that require this procedure, many children with a Fontan do not know any others like them. METHODS: With the cancelation of medically supervised heart camps due to the COVID-19 pandemic, we have organized several physician-led virtual day camps for children with a Fontan operation to connect with others in their province and across Canada. The aim of this study was to describe the implementation and evaluation of these camps via the use of an anonymous online survey immediately after the event and reminders on days 2 and 4 postevent. RESULTS: Fifty-one children have participated in at least 1 of our camps. Registration data showed that 70% of participants did not know anyone else with a Fontan. Postcamp evaluations showed that 86% to 94% learned something new about their heart and 95% to 100% felt more connected to other children like them. CONCLUSION: We have demonstrated the implementation of a virtual heart camp to expand the support network for children with a Fontan. These experiences may help to promote healthy psychosocial adjustments through inclusion and relatedness.

T1 mapping of the myocardium and liver in the single ventricle population.

BACKGROUND: Fontan associated liver disease (FALD) is an increasingly recognized complication of the single ventricle circulation characterized by hepatic venous congestion leading to hepatic fibrosis. Within the Fontan myocardium, fibrotic myocardial remodeling may occur and lead to ventricular dysfunction. Magnetic resonance imaging (MRI) T1 mapping can characterize both myocardial and liver properties. OBJECTIVE: The aim of this study was to compare myocardial and liver T1 between single ventricle patients with and without a Fontan and biventricular controls. MATERIALS AND METHODS: A retrospective study of 3 groups of patients: 16 single ventricle patients before Fontan (SVpre 2 newborns, 9 pre-Glenn, 5 pre-Fontan, 31% single right ventricle [SRV]), 16 Fontans (56% SRV) and 10 repaired d-transposition of the great arteries (TGA). Native modified Look-Locker inversion T1 times were measured in the myocardium and liver. Cardiac MRI parameters, myocardial and liver T1 values were compared in the three groups. Correlations were assessed between liver T1 and cardiac parameters. RESULTS: Myocardial T1 was higher in SVpre (1,056 ± 48 ms) and Fontans (1,047 ± 41 ms) compared to TGA (1,012 ± 48 ms, P < 0.05). Increased liver T1 was found in both SVpre (683 ± 82 ms) and Fontan (727 ± 49 ms) patients compared to TGA patients (587 ± 58 ms, P < 0.001). There was no difference between single left ventricle (SLV) versus SRV myocardial or liver T1. Liver T1 showed moderate correlations with myocardial T1 (r = 0.48, confidence interval [CI] 0.26-0.72) and ejection fraction (r = -0.36, CI -0.66-0.95) but not with other volumetric parameters. CONCLUSION: Increased liver T1 at both pre- and post-Fontan stages suggests there are intrinsic liver abnormalities early in the course of single ventricle palliation. Increased myocardial T1 and its relationship to liver T1 suggest a combination of edema from passive venous congestion and/or myocardial fibrosis occurring in this population. Liver T1 may provide an earlier marker of liver disease warranting further study.

The Diagnostic Role of Echocardiographic Strain Analysis in Patients Presenting with Chest Pain and Elevated Troponin: A Multicenter Study.

BACKGROUND: Myocarditis presenting as acute chest pain with elevated troponins without significant cardiac compromise is rare in previously healthy children, often referred to as myopericarditis. Diagnosis is challenging, as conventional echocardiographic measures of systolic function can be normal. The aim of this study was to demonstrate the diagnostic utility of strain imaging in this scenario. METHODS: This was a multicenter, retrospective study including patients presenting with chest pain and elevated troponin from 10 institutions who underwent cardiac magnetic resonance imaging and transthoracic echocardiography within 30 days of each other (group 1). Findings were compared with those among 19 control subjects (group 2). Clinical data and conventional echocardiographic and cardiac magnetic resonance imaging data were collected. Echocardiography-derived strain was measured at the core laboratory. Group 1 was divided into subgroups as myocarditis positive (group 1a) or negative (group 1b) on cardiac magnetic resonance imaging on the basis of established criteria. RESULTS: Group 1 included 108 subjects (88 in group 1a, 20 in group 1b). Although all groups had normal mean fractional shortening and mean left ventricular ejection fraction, group 1 had significantly lower ejection fraction (56.8 ± 7.0%) compared with group 2 (62.3 ± 4.9%; P < .005) and fractional shortening (31.2 ± 4.9%) compared with group 2 (34.1 ± 3.5%; P < .05). Additionally, peak global longitudinal strain (GLS) was markedly abnormal in group 1 (-13.9 ± 3.4%) compared with group 2 (-19.8 ± 2.1%; P < .001). In subgroup analysis, GLS was markedly abnormal in group 1a (-13.2 ± 3.0%) compared with group 1b (-17.3 ± 2.6%; P < .001). Fifty-four subjects underwent follow-up echocardiography (46 in group 1a, eight in group 1b), with mean a follow-up time of 10 ± 11 months. At follow-up, whereas ejection fraction and fractional shortening returned to normal in all patients, abnormalities in strain persisted in group 1, with 22% still having abnormal GLS. Moreover, mean GLS was more abnormal in group 1a (-16.1 ± 2.6%) compared with group 1b (-17.4 ± 1.2%; P < .05). CONCLUSIONS: The present study demonstrates that echocardiographic GLS is significantly worse in subjects with myopericarditis presenting with chest pain and elevated troponins compared with control subjects even when conventional measures of systolic function are largely normal and that these abnormalities persisted over time.

Some Things Change, Some Things Stay the Same: Trends in Canadian Education in Paediatric Cardiology and the Cardiac Sciences.

Education in paediatric cardiology has evolved along with clinical care. The availability and application of new technologies in education, in particular, have had a significant impact. Artificial intelligence; virtual, augmented, and mixed reality learning tools; and gamification of learning have all resulted in new opportunities for today's trainees compared with those of the past. A new training model is also being used. Though currently focused on residency education, competency-based medical education is also being applied to undergraduate education in some Canadian medical schools. Competency-based medical education offers a more transparent relationship between education and physicians' social contract with society. It provides greater accountability for programmes and learners to teach and learn the skills required to function as competent specialists. However, it has not come without challenges. Coincident with the application of this model for learners, there has been increased educational accountability for physicians in practice and for the institutions training them. Despite these changes, some things have remained the same. On the positive side, the importance of good clinical teachers to effective learning remains constant. Unfortunately, the mistreatment of learners within our education system also remains and is perhaps the most important challenge facing medical education in Canada today. Learning to be better teachers and learner advocates is an important goal for all of those involved in educating Canadian medical learners.

La formation en cardiologie pédiatrique a évolué parallèlement aux soins cliniques. L'accès à de nouvelles technologies dans la formation a eu une incidence particulièrement marquée. L'intelligence artificielle, les outils d'apprentissage faisant appel aux réalités virtuelles, augmentées et mixtes, et les ressorts ludiques sont tout autant d'outils qui n'étaient pas à la disposition des médecins en formation dans le passé. Un nouveau modèle de formation est également en place dans certaines écoles de médecine, où l'approche par compétences n'est plus seulement réservée aux résidents. Cette méthode d'enseignement permet d'établir une relation plus transparente entre la formation et le contrat social qui lie les médecins et la société. Elle permet une meilleure responsabilisation, tant du côté des enseignants que des apprenants, en ce qui concerne les compétences nécessaires pour bien outiller les spécialistes. Toutefois, ce modèle s'accompagne de certains défis puisqu'il engage davantage de responsabilités pour les médecins en exercice et les établissements de formation. En dépit de ces changements, certains éléments sont tout aussi importants que par le passé, notamment la présence de bons enseignants cliniques pour assurer un apprentissage efficace. Malheureusement, les apprenants continuent de vivre de grandes difficultés dans notre système de formation, et il s'agit peut-être du plus grand défi auquel font face les programmes canadiens de formation médicale. Apprendre à devenir de meilleurs enseignants et de meilleurs défenseurs des apprenants est un objectif important pour toutes les personnes qui s'emploient à former de nouveaux médecins au Canada.

Cardiac MRI-Derived Myocardial Deformation Parameters Correlate with Pulmonary Valve Replacement Indications in Repaired Tetralogy of Fallot.

Right ventricular (RV) volumetric cardiac magnetic resonance (CMR) criteria serve as indicators for pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (rTOF). Myocardial deformation and tricuspid valve displacement parameters may be more sensitive measures of RV dysfunction. This study's aim was to describe rTOF RV deformation and tricuspid displacement patterns using novel CMR semi-automated software and determine associations with standard CMR measures. Retrospective study of 78 pediatric rTOF patients was compared to 44 normal controls. Global RV longitudinal and circumferential strain and strain rate (SR) and tricuspid valve (TV) displacement were measured. Correlation analysis between strain, SR, TV displacement, and volumes was performed between and within subgroups. The sensitivity and specificity of strain parameters in predicting CMR criteria for PVR was determined. Deformation variables were reduced in rTOF compared to controls. Decreased RV strain and TV shortening were associated with increased RV volumes and decreased RVEF. Longitudinal and circumferential parameters were predictive of RVESVi (> 80 ml/m2) and RVEF (< 47%), with circumferential strain (> - 15.88%) and SR (> - 0.62) being most sensitive. Longitudinal strain was unchanged between rTOF subgroups, while circumferential strain trended abnormal in those meeting PVR criteria compared to controls. RV deformation and TV displacement are abnormal in rTOF, and RV circumferential strain variation may reflect an adaptive response to chronic volume or pressure load. This coupled with associations of ventricular deformation with traditional PVR indications suggest importance of this analysis in the evolution of rTOF RV assessment.

Dynamic Systolic Changes in Tricuspid Regurgitation Vena Contracta Size and Proximal Isovelocity Surface Area in Hypoplastic Left Heart Syndrome: A Three-Dimensional Color Doppler Echocardiographic Study.

BACKGROUND: The aims of this study were to investigate the dynamic changes in the vena contracta (VC) and proximal isovelocity surface area (PISA) through systole in patients with hypoplastic left heart syndrome and tricuspid regurgitation and to identify the stage of systole (early, mid, or late) in which VC and PISA radius are optimal. METHODS: Twenty-eight patients with hypoplastic left heart syndrome were prospectively studied using continuous two-dimensional (2D) and three-dimensional (3D) echocardiography. Two-dimensional VC width, 3D VC area, and PISA radii (2D and 3D) were measured frame by frame throughout systole. The maximal 2D VC width, 3D VC area, and PISA radii in the first, middle, and last thirds of systole were compared, and correlations were explored with 3D tricuspid annular areas, right atrial volumes, and right ventricular volumes. RESULTS: In all, 35 data sets that met inclusion criteria were analyzed. On frame-by-frame analysis, maximal 2D VC width and 3D VC area were found in the first third of systole in 17% and 20% of studies, in the second third in 34% and 31%, and in the final third in 49% and 49%. Similarly, the maximal 2D and 3D PISA radii were found in the first third of systole in 26% and 17% of studies, in the second third in 28% and 34%, and in the final third in 46% and 49%. CONCLUSIONS: In hypoplastic left heart syndrome, detailed temporal analysis of tricuspid regurgitation-associated VC and PISA by 2D and 3D echocardiography reveals no reliable pattern predicting when in systole these parameters peak. Frame-by-frame measurement is necessary for identification of maximal VC and PISA radius on 2D and 3D color Doppler echocardiography because the severity of tricuspid regurgitation could be underestimated because of temporal variability in VC and PISA.

Tricuspid Regurgitation in Hypoplastic Left Heart Syndrome: Three-Dimensional Echocardiography Provides Additional Information in Describing Jet Location.

BACKGROUND: Twenty-five percent of patients with hypoplastic left heart syndrome (HLHS) require tricuspid valve (TV) repair. The location of tricuspid regurgitation (TR) is important in determining the type of repair performed. Studies using three-dimensional echocardiography (3DE) have reported a high incidence of error on two-dimensional echocardiography (2DE) for the identification of TV leaflets. The aim of this study was to compare assessment of TR on 3DE and 2DE in patients with HLHS (jet location, TR grade, and reproducibility). METHODS: A retrospective, single-center review was performed. Fifty-six patients with HLHS with available two-dimensional and three-dimensional echocardiograms, and mild or greater TR, were included. TR location, grade, vena contracta area, and TV annular diameter were measured on 2DE and 3DE. Reproducibility was assessed by blinded reviewers. RESULTS: Three-dimensional echocardiography identified the primary jet location as central (57%) followed by anteroseptal (36%). There was poor agreement between findings on 3DE and 2DE for jet location (κ = 0.05; 95 CI, -0.08 to 0.19). Interobserver reproducibility for location on 3DE was excellent (κ = 0.8), whereas reproducibility for 2DE was poor (κ = 0.32). The most common jet location pre-Norwood and pre-Glenn was central (70%), whereas pre-Fontan and post-Fontan, jet location was central (45%) and anteroseptal (48%). Vena contracta area on 2DE correlated moderately with vena contracta area on 3DE (r = 0.60, P < .0001). TV annular diameters on 2DE and 3DE for lateral (r = 0.85, P < .0001) and anteroposterior (r = 0.74, P = .001) dimensions were strongly correlated. CONCLUSIONS: In children with HLHS, assessment of TR location on 2DE had poor agreement with assessment on 3DE and was poorly reproducible. In contrast, TR jet location on 3DE was highly reproducible. Pre-Glenn, a central TR jet was the most common, while post-Glenn, central and anteroseptal locations were equal, highlighting the importance of preoperative identification of TR jet location in patients with HLHS.

Right Ventricular Remodeling in Hypoplastic Left Heart Syndrome is Minimally Impacted by Cardiopulmonary Bypass: A Comparison of Norwood vs. Hybrid.

Right ventricular (RV) remodeling in hypoplastic left heart syndrome (HLHS) begins prenatally and continues through staged palliations. However, it is unclear if the most marked observed remodeling post-Norwood is secondary to cardiopulmonary bypass (CPB) exposure or if it is an adaptation intrinsic to the systemic RV. This study aims to determine the impact of CPB on RV remodeling in HLHS. Echocardiograms of HLHS survivors undergoing stage 1 Norwood (n = 26) or Hybrid (n = 20) were analyzed at pre- and post-stage 1, pre- and post-bidirectional cavo-pulmonary anastomosis (BCPA), and pre-Fontan. RV fractional area change (FAC), vector velocity imaging for longitudinal & derived circumferential deformation (global radial shortening (GRS) = peak radial displacement/end-diastolic diameter), and deformation ratio (longitudinal/ circumferential) were assessed. Both groups had similar age, clinical status and functional parameters pre-stage 1. No difference in RV size and sphericity at any stage between groups. RVFAC was normal (> 35%) throughout for both groups. Both Norwood and Hybrid patients had increased GRS (p = 0.0001) post-stage 1 and corresponding unchanged longitudinal strain, resulting in decreased deformation ratio (greater relative RV circumferential contraction), p = 0.0001. Deformation ratio remained decreased in both groups in subsequent stages. Irrespective of timing of the first CPB exposure, both Norwood and Hybrid patients underwent similar RV remodeling, with relative increase in circumferential to longitudinal contraction soon after stage 1 palliation. The observed RV remodeling in HLHS survivors were minimally impacted by CPB.

Tilt-table Echocardiography Unmasks Early Diastolic Dysfunction in Patients With Hemoglobinopathies.

Individuals with hemoglobinopathy (sickle cell anemia and thalassemia major) are at risk for cardiac complications such as heart failure and cardiomyopathy. Diastolic dysfunction is known to precede systolic dysfunction in many cardiac diseases. This study sought to determine whether changes in left atrial (LA) function during manipulation of cardiac preload by tilt-table echocardiography can unmask subclinical diastolic dysfunction in pediatric patients with hemoglobinopathies. Eleven sickle cell anemia, 9 transfusion-dependent thalassemia major, and 10 control subjects underwent tilt-table echocardiogram in the supine (loading) and 30-degree upright (unloading) positions and cardiac magnetic resonance imaging (MRI). Echocardiography assessed LA and left ventricular (LV) strain, strain rate, mitral inflow, and annular velocities. MRI assessed LV function, myocardial T1 and T2* for iron deposition. Both thalassemia major and sickle cell anemia patients had normal LV function and no evidence of cardiac iron deposition on MRI T2* measurements. During cardiac loading, controls appropriately increased LA conduit (P=0.002) and reservoir strain (P=0.002), mitral e' velocity (P<0.0001) and medial e' velocity (P=0.002), while the hemoglobinopathy patients showed no change in these parameters. In pediatric sickle cell anemia and thalassemia, tilt-table echocardiography unmasked a failure to augment LA function in response to loading, suggesting altered myocardial relaxation is present, before evidence of iron overload or systolic dysfunction.

Prenatal Detection, Comorbidities, and Management of Vascular Rings.

The 3-vessel and trachea view is now integrated into obstetrical screening and facilitates prenatal detection of vascular rings. We examined trends in prenatal detection, associated cardiac and extracardiac anomalies, and surgical management in this population. We reviewed a population-based cohort of pediatric vascular ring patients diagnosed prenatally and postnatally between 2002 and 2017 in Alberta, Canada. Of 106 cases, 28 (26%) had a prenatal diagnosis. Prenatal detection increased over time: 0/29 from 2002 to 2009, 4/28 (14%) from 2009 to 2011, 7/23 (30%) from 2012 to 2014, and 17/26 (65%) from 2015 to 2017 (p <0.01). The prenatal group more commonly had right aortic arch/left ductus/aberrant left subclavian artery (24/28vs 53/78, p = 0.04) and associated cardiac pathology (18/28vs 33/78, p = 0.05). The rate of genetic anomalies was overall higher than previously reported (34%) and did not differ between groups (11/28vs 25/78, p = 0.48). Those with a prenatal diagnosis were less likely to require cross-sectional imaging (9/28vs 48/78, p <0.01), modifying the vascular ring subtype diagnosis in 2 patients. Surgical intervention was common and did not differ between groups (24/28vs 66/78, p = 0.89). In conclusion, prenatal detection of vascular rings has increased. Despite differences in vascular ring subtype and associated cardiac pathology, the incidence of genetic anomalies and need for surgical intervention is not associated with timing of diagnosis. Genetic counseling should be universally offered. The diagnostic accuracy of echocardiography suggests additional imaging may not be routinely required.

Early tricuspid regurgitation in hypoplastic left heart syndrome is not related to right ventricular function or mechanical dyssynchrony

BACKGROUND: Tricuspid regurgitation (TR) is associated with morbidity and mortality in hypoplastic left heart syndrome (HLHS). We have previously demonstrated that TR prior to stage 2 (S2) surgical palliation is related to tricuspid valve (TV) abnormalities, including dilated annulus and increased leaflet prolapse. Right ventricular (RV) dysfunction and mechanical dyssynchrony have been reported as causes for TR. Thus, we hypothesized that TR and abnormal TV parameters are associated with RV dysfunction. Objective: This study explored the relationship between TV and RV function using quantitative three dimensional echocardiography (3DE) measure of TV parameters and speckle tracking echocardiography (STE) of RV deformation, in HLHS with and without TR. METHODS: Forty-four HLHS patients with median age of 4.7 months (IQR 3.9-5.3) were prospectively recruited prior to S2 palliation. TV parameters assessed using 3DE, included vena contracta area (VCA), leaflet area, prolapse volume, tethering volume, annular bending angle and papillary muscle angle. RV systolic function was assessed by fractional area change and STE derived longitudinal and circumferential strain, strain rate and mechanical dyssynchrony index (MDI). The group was divided into those with (group A) and those without (group B) significant TR by qualitative assessment. RV functional parameters were compared between the two groups using Mann-Whitney signed rank test and Spearman correlation of TV leaflet and annulus area, prolapse and tethering volume, bending angle and VCA, to longitudinal and circumferential strain, strain rate and MDI were performed. RESULTS: Fourteen patients (32%) had moderate or greater TR (group A). RV function parameters were not different between group A and group B. There was no correlation between all 3DE TV parameters and STE RV deformation parameters. CONCLUSION: Contrary to our hypothesis, HLHS RV systolic dysfunction and mechanical dyssynchrony do not play a significant role in early TR. This finding suggests the mechanisms of early TR in HLHS are likely to be secondary to valve and leaflet differences. (AU)

Speckle tracking echocardiography and magnetic resonance imaging derived circumferential strain rate are closely associated in the single right ventricle

BACKGROUND: Previous studies suggest right ventricular (RV) circumferential strain and strain rate from speckle tracking echocardiography (STE) is useful to assess function, despite imaging limitations of RV short axis and tracking algorithms designed for left ventricles. OBJECTIVE: This study compares STE strain and strain rate in patients with single RV to magnetic resonance imaging (MRI) derived strain and strain rate, using proprietary MRI deformation software with published validation in hypoplastic left heart syndrome. Strain and strain rate relationships to MRI derived volumes and function is explored. METHODS: Single RVs patients (n = 25) with STE and MRI performed with an interval up to 35 days, prior to stage 2 palliation (median age 3.9, range 0.9 - 6 months) were compared. STE (GE EchoPAC) and MRI derived longitudinal and circumferential strain and strain rate were analyzed offline. MRI RV end-diastolic (iEDV), end-systolic (iESV) volumes indexed to body surface area and ejection fraction were measured. Bland-Altman plot assessed agreement between the STE and MRI derived deformation measures. Correlations between variables were computed. RESULTS: STE and MRI strain rate had the best agreement between methods, longitudinal strain rate (bias -0.04%; SD 0.26) and circumferential strain rate (bias 0.16 %; SD 0.20) while STE and MRI strain had minimal bias and an acceptable limits of agreement, longitudinal strain (bias 0.4 %; SD 3.2) and circumferential strain (bias -1.7 %; SD 4.4). Greater STE and MRI derived strain and strain rate is associated with smaller iEDV, iESV and greater ejection fraction (see table). MRI circumferential strain and strain rate has a greater correlation with volumes and ejection fraction than MRI longitudinal strain and strain rate. STE circumferential strain rate was best correlated MRI derived volumes and ejection fraction. CONCLUSION: In single RV, STE and MRI derived strain and strain rate showed good agreement, with strain rate having the best equivalency. Furthermore, STE an MRI circumferential strain rate was the most consistently related to MRI derived RV size and function. This study reaffirms the performance of commercially available STE software in single RV and further emphasizes the importance of including circumferential deformation in routine evaluation. (AU)

Reduced Right Ventricular Fractional Area Change, Strain, and Strain Rate before Bidirectional Cavopulmonary Anastomosis is Associated with Medium-Term Mortality for Children with Hypoplastic Left Heart Syndrome.

BACKGROUND: Ventricular dysfunction is associated with increased morbidity and mortality in children with hypoplastic left heart syndrome. The aim of this study was to assess the diagnostic performance of conventional and speckle-tracking echocardiographic measures of right ventricular (RV) function before bidirectional cavopulmonary anastomosis palliation in predicting death or need for heart transplantation (HTx). METHODS: RV fractional area change (RVFAC) and longitudinal and circumferential strain and strain rate (SR) were measured in 64 prospectively recruited patients with hypoplastic left heart syndrome from echocardiograms obtained before bidirectional cavopulmonary anastomosis surgery. The composite end point of death or HTx was examined. Receiver operating characteristic analysis was performed, and cutoff values optimizing sensitivity and specificity were derived. RESULTS: At a median follow-up of 5.0 years (interquartile range, 2.8-6.4 years), 13 patients meeting the composite end point had lower longitudinal strain and SR, circumferential SR, and RVFAC compared with survivors (n = 51). The conventional cutoff of RVFAC < 35% was specific for death or HTx (86%) but had poor sensitivity (46%), with an area under the curve of 0.73. Speckle-tracking echocardiographic variables showed similar areas under the curve (range, 0.69-0.79), with negative predictive values >90%. Addition of speckle-tracking echocardiographic variables to RVFAC < 35% showed no added benefit. However, in a subpopulation of patients with RVFAC ≥ 35% (n = 44), those meeting the composite end point (n = 7) had lower longitudinal SR (median, -1.0 1/sec [interquartile range, -0.8 to -1.1 1/sec] vs -1.21/sec [interquartile range, -1.0 to -1.3 1/sec], P = .03). Interobserver reproducibility was superior for longitudinal strain and SR (intraclass correlation coefficient > 0.92) compared with RVFAC (intraclass correlation coefficient = 0.75). CONCLUSIONS: Children with hypoplastic left heart syndrome with normal RVFAC and ventricular deformation before bidirectional cavopulmonary anastomosis have a low likelihood of death or HTx in the medium term. In the presence of reduced RVFAC, speckle-tracking echocardiography does not provide additional prognostic value. However, in patients with "normal" RVFAC, it may have a role in improving outcome prediction and warrants further investigation.

Tricuspid Valve Adaptation during the First Interstage Period in Hypoplastic Left Heart Syndrome.

BACKGROUND: Tricuspid regurgitation (TR) is an important risk factor for morbidity and mortality in hypoplastic left heart syndrome (HLHS), yet the evolution of tricuspid valve (TV) dysfunction in HLHS is poorly understood. This study sought to examine changes in TV function in HLHS between the first two stages of surgical palliation and to determine the mechanism of TR at the time of stage two surgery-bidirectional cavopulmonary anastomosis (BCPA). METHODS: We prospectively investigated 44 infants at two time points-prior to Norwood-Sano (T1 - median age 5.4 days) and prior to BCPA (T2 - median age 4.7 months) using two-dimensional (2DE) and three-dimensional echocardiography (3DE). Right ventricular (RV) size, function and shape was assessed with 2DE. Extracted spatial coordinates from 3DE were used to calculate TV leaflet and annular area, tethering and prolapse volumes, bending angle, and coaptation index. TR was graded qualitatively, and 2D and 3D vena contracta (VC) were measured. RESULTS: The cohort from T1 to T2 had increased indexed leaflet and annular area (P < .0001) and tethering volume (P < .0001), with no change in coaptation. Significant TR was present in 14 infants (32%) at T2 and was associated with greater leaflet (P = .02) and annular areas (P = .002) and greater prolapse volume (P = .008), but not tethering volume or reduced coaptation. At latest follow-up (median 23 months), 13 patients died or required transplantation. Only 3DE VC at T2 was associated with death or transplantation. CONCLUSIONS: The TV in HLHS adapts to interstage stressors (increased preload and afterload) by increasing leaflet size to maintain adequate leaflet coaptation. Significant TR at T2 was associated with greater leaflet size and prolapse. This may represent TV maladaptation from an excessive response in leaflet expansion to stressors.