The Fate of the Left Ventricular Outflow Tract Following Interrupted Aortic Arch Repair.

Objectives: To examine the probability of left ventricular outflow tract (LVOT) reintervention following interrupted aortic arch (IAA) repair in neonates with LVOT obstruction (LVOTO) risk. Methods: This retrospective multicenter study included 150 neonates who underwent IAA repair (2003-2017); 100 of 150 (67%) had isolated IAA repair (with ventricular septal defect closure) and 50 of 150 (33%) had concomitant LVOT intervention: conal muscle resection (n = 16), Ross-Konno (n = 7), and Yasui operation (n = 27: single-stage n = 8, staged n = 19). Demographic and morphologic characteristics were reviewed. Factors associated with LVOT reoperation were explored using multivariable analysis. Results: Concomitant LVOT intervention was more likely in neonates with type B IAA, bicuspid aortic valve, aberrant right subclavian artery, smaller aortic valve annulus, and ascending aorta dimensions. On follow-up, five-year freedom from LVOT reoperation was highest following Ross-Konno (100%), 77% following Yasui (mainly for neo-aortic regurgitation), 77% following isolated IAA repair (mainly for LVOTO), and 47% following IAA repair with concomitant conal resection, P = .033. While all patients had low peak LVOT gradient at time of discharge, those who had conal resection developed higher gradients on follow-up (P = .007). Ross-Konno and Yasui procedures were associated with higher right ventricular outflow tract (RVOT) reoperation. In the cohort following isolated IAA repair, aortic sinus Z score was associated with LVOT reoperation. Conclusions: Both Yasui and Ross-Konno operations effectively mitigate late LVOTO risk. The highest risk of reintervention for LVOTO was associated with conal muscle resection while the lowest risk is associated with Ross-Konno. The RVOT reoperation risk in patients who had Ross-Konno or Yasui does not seem to affect survival.

Progression of an Artificial Intelligence Chatbot (ChatGPT) for Pediatric Cardiology Educational Knowledge Assessment.

Artificial intelligence chatbots, like ChatGPT, have become powerful tools that are disrupting how humans interact with technology. The potential uses within medicine are vast. In medical education, these chatbots have shown improvements, in a short time span, in generalized medical examinations. We evaluated the overall performance and improvement between ChatGPT 3.5 and 4.0 in a test of pediatric cardiology knowledge. ChatGPT 3.5 and ChatGPT 4.0 were used to answer text-based multiple-choice questions derived from a Pediatric Cardiology Board Review textbook. Each chatbot was given an 88 question test, subcategorized into 11 topics. We excluded questions with modalities other than text (sound clips or images). Statistical analysis was done using an unpaired two-tailed t-test. Of the same 88 questions, ChatGPT 4.0 answered 66% of the questions correctly (n = 58/88) which was significantly greater (p < 0.0001) than ChatGPT 3.5, which only answered 38% (33/88). The ChatGPT 4.0 version also did better on each subspeciality topic as compared to ChatGPT 3.5. While acknowledging that ChatGPT does not yet offer subspecialty level knowledge in pediatric cardiology, the performance in pediatric cardiology educational assessments showed a considerable improvement in a short period of time between ChatGPT 3.5 and 4.0.

Mechanical atrioventricular valve replacement in patients with single ventricle palliation.

OBJECTIVES: Atrioventricular valve (AVV) replacements in patients with single-ventricle circulations pose significant surgical risks and are associated with high morbidity and mortality. METHODS: From 1997 to 2021, 16 consecutive patients with functionally single-ventricle physiology underwent mechanical AVV replacement. Primary outcome was transplant-free survival. Secondary outcomes included major postoperative morbidity. RESULTS: The median age of AVV replacement was 2 years old (interquartile range 0.6-3.8 years). All AVV replacements were performed with a St. Jude Medical mechanical valve, median 24 mm (range, 19-31mm). Extracorporeal membrane oxygenation (ECMO) was required in 4 patients. Operative mortality was 38% (6/16). There were 2 late deaths and 3 transplants. Transplant-free survival was 50% at 1 year, 37.5% at 5 years, and 22% at 10 years. Transplant-free survival was higher for patients with preserved ventricular function (P = 0.01). Difference in transplant-free survival at 1 year was 75% vs 25%, at 5 years was 62.5% vs 12.5% and at 10 years was 57% vs 0%. Three (19%) patients had complete heart block requiring permanent pacemaker insertion. 6 of 13 patients (46%) patients reached Fontan completion (3 patients operated at/after Fontan). Significant bleeding events occurred in 8 patients (50%) with 3 patients suffering major cerebrovascular accidents. There were 6 events of valve thrombosis in 5 patients, resulting in 2 deaths and 2 heart transplants. CONCLUSIONS: Mechanical valve replacement carries significant morbidity and mortality risk. While it successfully salvages about half of patients with preserved ventricular function, careful consideration of alternative options should be made before embarking upon mechanical valve replacement.

Melody Mitral Valve Is a Promising Alternative to Mechanical Valve Replacement for Young Children.

PURPOSE: The purpose of this study was to compare outcomes of Melody mitral valve to mechanical mitral valve replacement (MVR) for young children. DESCRIPTION: Children who underwent Melody MVR from 2014 to 2020 were case-matched to mechanical MVR patients. Transplant-free survival and cumulative incidence of reintervention were compared. A subanalysis was performed for infants aged < 1 year (9 Melody MVRs and their matches). EVALUATION: Twelve children underwent Melody MVR. Two children (17%) salvaged from mechanical support died. Five of 10 survivors (50%) had subsequent MVR. At 1 and 3 years, transplant-free survival (Melody: 83%, 83%; mechanical: 83%, 67%; P = .180) and reintervention (Melody: 9%, 39%; mechanical: 0%, 18%; P = .18) were equivalent between groups. For children < 1 year of age, Melody MVR had a modest survival benefit (Melody: 89%, 89%; mechanical: 80%, 60%; P = .046), while rate of reintervention remained equivalent (Melody: 13%, 32%; mechanical: 0%, 22%; P = .32). CONCLUSIONS: For patients < 1 year old, Melody MVR offers a promising alternative and is a reasonable bridge to mechanical MVR, which can be performed safely at an older age. Further studies are necessary to corroborate these findings.

Pediatric and Adult Cardiologists' and Respirologists' Referral Practices to Palliative Care.

CONTEXT: Children and adults with advanced cardiac or respiratory disease may benefit from specialized palliative care (SPC), but there has been little SPC research in this area. OBJECTIVES: To explore pediatric cardiologists' and respirologists' (pediatric clinicians) beliefs about and referral practices to SPC and compare these results to adult cardiologists and respirologists (adult clinicians). METHODS: Pediatric and adult clinicians were sent a survey exploring SPC referral practices and beliefs. Responses were summarized with descriptive statistics. Pediatric and adult clinicians' responses were compared using Pearson's chi-square test. RESULTS: The response rate was 56% (989/1759); 9% (87/989) were pediatric clinicians. Pediatric clinicians were more likely than adult clinicians to be female, work in an academic center, and experience fewer patient deaths (P<0.001). Pediatric clinicians reported better access to SPC clinical nurse specialists, spiritual care specialists and bereavement counselors (P<0.001), while adult clinicians reported better access to palliative care units (P<0.001). Pediatric clinicians referred to SPC earlier, while adult clinicians tended to refer after disease directed therapies were stopped (P<0.001). More than half of all clinicians felt patients had negative perceptions of the phrase "palliative care". Although most clinicians were satisfied with SPC quality (73-82%), fewer adult clinicians were satisfied with SPC availability (74 vs. 47%; P<0.001). Fewer pediatric clinicians felt that SPC prioritized oncology patients (13 vs. 53%; P<0.001). CONCLUSION: There are important differences between pediatric and adult clinicians' beliefs about and referral practices to SPC. This may reflect unique features of pediatric diseases, provider characteristics, care philosophies, or service availability.

Organization of Pediatric Echocardiography Laboratories: Impact of Sonographers on Clinical, Academic, and Financial Performance.

Echocardiography has evolved the first-line imaging for diagnosis and management of pediatric and congenital heart disease all over the world. While it recognized as essential component of pediatric cardiac care delivery, organization of pediatric echocardiography services is very heterogeneous across the world, mainly related to significant differences in material and human resources in heterogeneous health care systems. In this paper, we focus on the role of pediatric sonographers, defined as expert technicians in pediatric echocardiography. While in some services sonographers are an essential part of the organizational structure, other laboratories operate only with physicians trained in echocardiography. The impact of sonographers on clinical, academic and financial performance will be discussed. Two organizational models (with and without sonographers) will be compared, and the advantages and disadvantages of each model will be evaluated. Different models of care provision are possible and decisions on organizational models need to be adjusted to the demands and available resources.

Prospective Assessment of Coronary Artery Flows Before and After Cardiopulmonary Bypass in Children With a Spectrum of Congenital Heart Disease.

Background: Normative data for the effect of cardiopulmonary bypass (CPB) on coronary artery Doppler velocities by transesophageal echocardiography in paediatric patients with congenital heart disease (CHD) are lacking. The objective of the study was to prospectively examine the effects of CPB on coronary artery flow patterns by transesophageal echocardiography before and after CPB in children with CHD. Methods: All cases undergoing CHD surgery at the Hospital for Sick Children, Toronto, were eligible. The excluded cases included Norwood operation, heart transplantation, or weight <2.5 kg. Coronary Dopplers and coronary flow reserve (CFR) for the right coronary artery (RCA) and left anterior descending (LAD) were obtained. Multivariable analyses using linear regression models were performed, adjusted for age and cross-clamp time. Results: From May 2017 to June 2018, 69 children (median age at surgery: 0.7 years, interquartile range [IQR]: 0.4-3.7 years; median weight: 7.4 kg, IQR: 5.8-13.3 kg) were included. They were grouped into shunt lesions (N = 26), obstructive lesions (N = 26), transposition of the great arteries (N = 5), and single ventricle (N = 12). N = 39 (57%) were primary repairs, and 56 (81%) had 1 CPB run. For RCA and LAD peak velocities, there was an increase from pre- to post-CPB in RCA peak 39 cm/s (IQR: 30-54 cm/s) to 65 cm/s (IQR: 47-81 cm/s), P < 0.001, mean CFR 1.52 (IQR: 1.25-1.81), and LAD peak 49 cm/s (IQR: 39-60 cm/s) to 70 cm/s (IQR: 52-90 cm/s), P < 0.001, mean CFR 1.48 (IQR: 1.14-1.77). Conclusions: Coronary flow velocities increase from pre- to post-CPB in congenital heart lesions. CFR is consistent across all lesions but is relatively low compared with the adult population.

Contexte: On ne dispose pas de données normatives sur les effets de la dérivation cardiopulmonaire (DCP) sur le débit coronarien mesuré au moyen d'une échocardiographie transœsophagienne Doppler chez des enfants présentant une cardiopathie congénitale. L'objectif de l'étude était d'examiner de manière prospective les effets de la DCP sur le débit coronarien avant et après l'intervention chez des enfants présentant une cardiopathie congénitale. Méthodologie: Tous les enfants ayant subi une intervention chirurgicale pour une cardiopathie congénitale à l'Hospital for Sick Children de Toronto étaient admissibles à l'étude, à l'exception de ceux ayant subi une intervention de Norwood ou une transplantation cardiaque, de même que les enfants pesant moins de 2,5 kg. Les résultats du test Doppler et la réserve coronarienne pour l'artère coronaire droite (ACD) et la branche antérieure de l'artère coronaire gauche (ACG) ont été obtenus. Des analyses multivariées ont été réalisées au moyen de modèles de régression linéaire, avec correction en fonction de l'âge et du temps de clampage total. Résultats: Entre mai 2017 et juin 2018, 69 enfants (âge médian au moment de la chirurgie : 0,7 an, intervalle interquartile (IIQ) : 0,4-3,7 ans; poids médian : 7,4 kg, IIQ : 5,8-13,3 kg) ont été inclus dans l'étude. Les sujets ont été répartis en quatre groupes : shunts (n = 26), lésions obstructives (n = 26), permutation des gros vaisseaux (n = 5) et ventricule unique (n = 12). Chez 39 sujets (57 %), il s'agissait d'une réparation primitive, et 56 enfants (81 %) avaient déjà subi une DCP. Les vitesses maximales dans l'ACD et dans la branche antérieure de l'ACG ont augmenté après la DCP, passant de 39 cm/s (IIQ : 30-54 cm/s) à 65 cm/s (IIQ : 47-81 cm/s), p < 0,001; réserve coronarienne moyenne : 1,52 (IIQ : 1,25-1,81) pour l'ACD, et de 49 cm/s (IIQ : 39-60 cm/s) à 70 cm/s (IIQ : 52-90 cm/s), p < 0,001; réserve coronarienne moyenne : 1,48 (IIQ : 1,14-1,77) pour la branche antérieure de l'ACG. Conclusions: Le débit coronarien augmente après une DCP dans les cas de lésions cardiaques congénitales. La réserve coronarienne est constante dans tous les types de lésions, mais elle est relativement faible comparativement à celle de la population adulte.

Asymmetric assembly of centromeres epigenetically regulates stem cell fate.

Centromeres are epigenetically defined by CENP-A-containing chromatin and are essential for cell division. Previous studies suggest asymmetric inheritance of centromeric proteins upon stem cell division; however, the mechanism and implications of selective chromosome segregation remain unexplored. We show that Drosophila female germline stem cells (GSCs) and neuroblasts assemble centromeres after replication and before segregation. Specifically, CENP-A deposition is promoted by CYCLIN A, while excessive CENP-A deposition is prevented by CYCLIN B, through the HASPIN kinase. Furthermore, chromosomes inherited by GSCs incorporate more CENP-A, making stronger kinetochores that capture more spindle microtubules and bias segregation. Importantly, symmetric incorporation of CENP-A on sister chromatids via HASPIN knockdown or overexpression of CENP-A, either alone or together with its assembly factor CAL1, drives stem cell self-renewal. Finally, continued CENP-A assembly in differentiated cells is nonessential for egg development. Our work shows that centromere assembly epigenetically drives GSC maintenance and occurs before oocyte meiosis.

Predictors of Bicuspid Aortic Valve-Associated Aortopathy in Childhood: A Report From the MIBAVA Consortium.

BACKGROUND: Bicuspid aortic valve (BAV) is the most prevalent congenital heart defect affecting 1% to 2% of the population. It is associated with ascending aorta dilatation. Valve morphology, aortic stenosis (AS), and aortic insufficiency (AI) have been proposed as potential risk factors; however, evaluating their role is difficult, as these factors are inherently related. The aim of this study was to determine whether BAV morphology and dysfunction are independent determinants for ascending aorta dilatation in pediatric patients. METHODS: A multicenter, retrospective, cross-sectional study of pediatric BAV patients followed since 2004 was performed. Imaging data were assessed for BAV morphology, severity of AS and AI, history of coarctation, and aortic dimensions. Associations were determined using multivariable regression analysis. A subset of patients undergoing aortic interventions (balloon dilation or Ross) were assessed longitudinally. RESULTS: Data were obtained from 2122 patients (68% male; median age 10.2 years). Fifty percent of patients had ascending aorta dilatation. Right and noncoronary cusp fusion, increasing AS and AI, and older age were independently associated with ascending aorta dilatation. A history of coarctation was associated with less ascending aorta dilatation. In patients with neither AS nor AI, 37% had ascending aorta dilatation (4% severe). No complications related to aortic dilatation occurred in this cohort. Aortic Z scores were determined, and a Z-score calculator was created for this population. CONCLUSIONS: In this large pediatric cohort of patients with BAV, valve morphology, AS, and AI are independently associated with ascending aorta dilatation, suggesting that hemodynamic factors influence aortopathy. However, even in BAVs with no AS or AI, there is significant ascending aorta dilatation independent of valve morphology. Interventions that led to changes in degree of AI and AS did not seem to influence change in aortic dimensions. The current BAV cohort can be used as a reference group for expected changes in aortic dimensions during childhood.

Contemporary Outcomes and Factors Associated With Mortality After a Fetal or Postnatal Diagnosis of Common Arterial Trunk.

BACKGROUND: Common arterial trunk (CAT) is a rare anomaly with a spectrum of pathology. We sought to identify current trends and factors associated with postnatal outcomes. METHODS: This was a single-centre review including 153 live births with planned surgery. Patients were analyzed as 2 cohorts based on era of CAT diagnosis (1990 to 1999 vs 2000 to 2014) and complexity of disease (simple vs complex). "Complex" required the association with significant aortic arch obstruction, truncal valve (TV) stenosis/regurgitation, and/or branch pulmonary artery (PA) hypoplasia, respectively. RESULTS: Sixteen (10%) died preoperatively, and this outcome was associated with significant TV stenosis (odds ratio [OR] 4.55; P = 0.01) and regurgitation (OR 3.17; P = 0.04); 130 (95%) of 137 operated infants underwent primary complete repair. Their survival rates to 1 year improved from 54% to 85% after 2000, although this outcome remained substantially lower for cases with a complex vs simple CAT repair (76% vs 95%; OR 6.46; P = 0.006). Other risk factors associated with decreased 1-year survival included diagnosis before 2000 (OR 4.48; P = 0.038) and a lower birth weight (OR 8.0 per kg weight; P = 0.001). Finally, of 93 survivors beyond year 1 of life, 76 (82%) had undergone a total of 224 reinterventions. Only 15 (16%) were alive without any surgical or catheter-based reintervention at study end. CONCLUSIONS: Despite recent surgical improvements, postnatal mortality continues to be substantial if CAT is complicated by significant pathology of the TV, aortic arch, or branch PAs. Reoperations and catheter interventions are eventualities for most patients during childhood.

Improving Prenatal Diagnosis of Coarctation of the Aorta.

BACKGROUND: The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta. METHODS: A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves. RESULTS: Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention. CONCLUSIONS: In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler.

Pre-intervention morphologic and functional echocardiographic characteristics of neonates with critical left heart obstruction: a Congenital Heart Surgeons Society (CHSS) inception cohort study.

AIMS: The aims of this study were to provide a detailed descriptive analysis of pre-intervention morphologic and functional echocardiographic parameters in a large, unselected, multicentre cohort of neonates diagnosed with critical left heart obstruction and to compare echocardiographic features between the different subtypes of left-sided lesions. METHODS AND RESULTS: Pre-intervention echocardiograms for 651 patients from 19 Congenital Heart Surgeons' Society (CHSS) institutions were reviewed in a core lab according to a standardized protocol including >150 morphologic and functional variables. The four most common subtypes of lesions were: aortic atresia (AA)/mitral atresia (MA) (29% of patients), AA/mitral stenosis (MS) (20%), aortic stenosis (AS)/MS (26%), and isolated AS (iAS) (18%). Only 17% of patients with AS/MS had an apex-forming left ventricle, compared with 0% of those with AA/MA and AA/MS (P < 0.0001). Aortic arch hypoplasia and coarctation were common across all four groups, while those with AA/MA and AA/MS had the smallest ascending aorta diameters. Flow in the ascending aorta was retrograde in 43% and 10% of the patients with AS/MS and iAS, respectively. The right ventricle was apex forming in 100% of patients with AA/MA and AA/MS, 96% with AS/MS and 70% with iAS (P < 0.0001). Moderate to severe tricuspid regurgitation was present in 13% of all patients. CONCLUSION: This large multi-institutional study generates insight into the distribution of the functional and morphologic spectrum in patients with critical left-sided heart disease and identifies differences in these functional and morphologic characteristics between the main anatomic subtypes of critical left heart obstruction.

Understanding the mechanism for branch pulmonary artery stenosis after the arterial switch operation for transposition of the great arteries.

AIMS: The pathophysiology of branch pulmonary artery (PA) stenosis after the arterial switch operation, most commonly on the left, is incompletely understood. This study examines factors associated with left PA (LPA) obstruction. METHODS AND RESULTS: Cardiac magnetic resonance (CMR) imaging studies performed in patients after arterial switch operation (ASO) were retrospectively analysed. Blood flow was measured in both branch PAs and neo-pulmonary root position in relation to the aorta was expressed as an angle, relative to a line connecting the sternum and the spine. Sixty-six patients were included for analysis. Seventy per cent (n = 46) had balanced pulmonary blood flow, 28% (n = 18) had decreased flow to the left, and 2% (n = 2) had decreased flow to the right lung. LPA area indexed to body surface area (BSA) was smaller than RPA area (62 ± 37 vs. 120 ± 64 mm2/m2, P < 0.0001). Patients with reduced LPA flow were more likely to have required pulmonary arterioplasty at the time of ASO (17 vs. 2%, P = 0.04) and had a larger aortic root diameter (25 ± 7 vs. 22 ± 5 mm2/m2, P = 0.01). Greater rightward orientation of the neo-pulmonary root correlated inversely with LPA cross-sectional area (r = -0.39, P = 0.001) but not with LPA flow. Aortic root diameter correlated inversely with LPA flow (r = -0.43, P = 0.0004) but not with LPA cross-sectional area (P = 0.32). Patients with a rightward neo-pulmonary root and/or a dilated aortic root in the upper quartile range had a smaller LPA area (53 vs. 73 mm2/m2, P = 0.04) and less pulmonary blood flow (41 vs. 46%, P = 0.02) compared with patients without those risk factors. CONCLUSIONS: Neo-pulmonary to neo-aortic geometry as well as post-operative compression of the LPA by an enlarged aorta impact LPA size and perfusion of the left lung.

Transcatheter stenting of the right ventricular outflow tract augments pulmonary arterial growth in symptomatic infants with right ventricular outflow tract obstruction and hypercyanotic spells.

We retrospectively reviewed all the children with right ventricular outflow tract obstruction, hypoplastic pulmonary annulus, and pulmonary arteries who underwent stenting of the right ventricular outflow tract for hypercyanotic spells at our institution between January, 2008 and December, 2013; nine patients who underwent cardiac catheterisation at a median age of 39 days (range 12-60 days) and weight of 3.6 kg (range 2.6-4.3 kg) were identified. The median number of stents placed was one stent (range 1-4). The median oxygen saturation increased from 60% to 96%. The median right pulmonary artery size increased from 3.3 to 5.5 mm (-2.68 to -0.92 Z-score), and the median left pulmonary artery size increased from 3.4 to 5.5 mm (-1.93 to 0 Z-scores). Among all, one patient developed transient pulmonary haemorrhage, and one patient had pericardial tamponade requiring drainage. Complete repair of tetralogy of Fallot +/- atrioventricular septal defect or double-outlet right ventricle was achieved in all nine patients. Transcatheter stent alleviation of the right ventricular outflow tract obstruction resolves hypercyanotic spells and allows reasonable growth of the pulmonary arteries to facilitate successful surgical repair. This represents a viable alternative to placement of a systemic-to-pulmonary artery shunt, particularly in small neonates.

Outcome, incidence and risk factors for stroke after pediatric heart transplantation: An analysis of the International Society for Heart and Lung Transplantation Registry.

BACKGROUND: In the registry of the International Society for Heart and Lung Transplantation (ISHLT), cerebrovascular accidents are the fifth most common cause for mortality after pediatric heart transplantation (PHTx), but details are lacking in the literature. The purpose of this analysis of the ISHLT registry was to determine the prevalence, risk factors and outcomes of stroke after PHTx. METHODS: Data from the ISHLT registry (1998 to 2010) were used to identify all patients whose primary transplantation was performed at <18 years of age. Of the 10,441 transplants reviewed, 9,837 primary transplants and 604 retransplants were analyzed. RESULTS: Three hundred thirty-three (3%) patients had a stroke after PHTx; 54% were male, median age at PHTx was 6 years (0 to 17 years), and 44% had a diagnosis of congenital heart disease (CHD). Freedom from stroke was 99% at 1 month, 97% at 5 years, 95% at 10 years and 91% at 20 years post-PHTx. After a stroke, survival at 1 month, 1 year and 5 years was 83%, 69% and 55%, respectively. Multivariable independent risk factors for stroke included a primary diagnosis of congenital heart disease [hazard ratio (HR) 1.4 (1.1 to 1.7), p = 0.01], previous stroke [HR 4.5 (3.2 to 6.2), p < 0.001], history of aborted sudden death [HR 1.5 (1.1 to 2), p = 0.01], ventricular assist device [HR 1.5 (1.1 to 2.2), p = 0.03] or extracorporeal membrane oxygenation [HR 1.7 (1.2 to 2.2), p = 0.01], post-operative dialysis [HR 3.3 (2.3 to 4.7), p < 0.001], infection requiring antibiotics before discharge [HR 1.9 (1.4 to 2.5), p < 0.001], pacemaker implantation [HR 1.6 (1 to 2.5), p = 0.04] or drug-treated hypertension [HR 1.4 (1.1 to 1.8), p = 0.003] during follow-up. CONCLUSIONS: Stroke after pediatric heart transplantation is associated with increased mortality. Congenital heart disease and mechanical support both portend greater risk, in addition to markers of increased pre- and post-transplant medical acuity.

Chromosome 22q11.21 microduplication in association with hypoplastic left heart syndrome with hypoplastic pulmonary arteries.

We describe a case of a baby girl born with hypoplastic left heart syndrome consisting of mitral atresia, aortic atresia, hypoplastic ascending aorta, and left ventricle. The pulmonary arteries were hypoplastic, measuring 3 mm. Fluorescence in situ hybridisation analysis demonstrated a microduplication of chromosome 22q11.2. Subsequent array comparative genomic hybridisation showed a gain of 2.3 Mb in one copy of chromosome 22q at band 22q11.21. The proband underwent a successful Norwood procedure with Sano shunt and subsequently underwent bi-directional Glenn shunt and Fontan procedure. This report highlights the association between hypoplastic left heart syndrome with hypoplastic pulmonary arteries and chromosome 22q11.21 microduplication.