Impaired Reorganization of Centrosome Structure Underlies Human Infantile Dilated Cardiomyopathy.

BACKGROUND: During cardiomyocyte maturation, the centrosome, which functions as a microtubule organizing center in cardiomyocytes, undergoes dramatic structural reorganization where its components reorganize from being localized at the centriole to the nuclear envelope. This developmentally programmed process, referred to as centrosome reduction, has been previously associated with cell cycle exit. However, understanding of how this process influences cardiomyocyte cell biology, and whether its disruption results in human cardiac disease, remains unknown. We studied this phenomenon in an infant with a rare case of infantile dilated cardiomyopathy (iDCM) who presented with left ventricular ejection fraction of 18% and disrupted sarcomere and mitochondria structure. METHODS: We performed an analysis beginning with an infant who presented with a rare case of iDCM. We derived induced pluripotent stem cells from the patient to model iDCM in vitro. We performed whole exome sequencing on the patient and his parents for causal gene analysis. CRISPR/Cas9-mediated gene knockout and correction in vitro were used to confirm whole exome sequencing results. Zebrafish and Drosophila models were used for in vivo validation of the causal gene. Matrigel mattress technology and single-cell RNA sequencing were used to characterize iDCM cardiomyocytes further. RESULTS: Whole exome sequencing and CRISPR/Cas9 gene knockout/correction identified RTTN, the gene encoding the centrosomal protein RTTN (rotatin), as the causal gene underlying the patient's condition, representing the first time a centrosome defect has been implicated in a nonsyndromic dilated cardiomyopathy. Genetic knockdowns in zebrafish and Drosophila confirmed an evolutionarily conserved requirement of RTTN for cardiac structure and function. Single-cell RNA sequencing of iDCM cardiomyocytes showed impaired maturation of iDCM cardiomyocytes, which underlie the observed cardiomyocyte structural and functional deficits. We also observed persistent localization of the centrosome at the centriole, contrasting with expected programmed perinuclear reorganization, which led to subsequent global microtubule network defects. In addition, we identified a small molecule that restored centrosome reorganization and improved the structure and contractility of iDCM cardiomyocytes. CONCLUSIONS: This study is the first to demonstrate a case of human disease caused by a defect in centrosome reduction. We also uncovered a novel role for RTTN in perinatal cardiac development and identified a potential therapeutic strategy for centrosome-related iDCM. Future study aimed at identifying variants in centrosome components may uncover additional contributors to human cardiac disease.

Evaluating threshold for donor fraction cell-free DNA using clinically available assay for rejection in pediatric and adult heart transplantation.

BACKGROUND: The aims of the study were to assess the performance of a clinically available cell-free DNA (cfDNA) assay in a large cohort of pediatric and adult heart transplant recipients and to evaluate performance at specific cut points in detection of rejection. METHODS: Observational, non-interventional, prospective study enrolled pediatric and adult heart transplant recipients from seven centers. Biopsy-associated plasma samples were used for cfDNA measurements. Pre-determined cut points were tested for analytic performance. RESULTS: A total of 487 samples from 160 subjects were used for the analysis. There were significant differences for df-cfDNA values between rejection [0.21% (IQR 0.12-0.69)] and healthy samples [0.05% (IQR 0.01-0.14), p < .0001]. The pediatric rejection group had a median df-cfDNA value of 0.93% (IQR 0.28-2.84) compared to 0.09% (IQR 0.04-0.23) for healthy samples, p = .005. Overall negative predictive value was 0.94 while it was 0.99 for pediatric patients. Cut points of 0.13% and 0.15% were tested for various types of rejection profiles and were appropriate to rule out rejection. CONCLUSION: The study suggests that pediatric patients with rejection show higher levels of circulating df-cfDNA compared to adults and supports the specific cut points for clinical use in pediatric and adult patients with overall acceptable performance.

Postoperative Morbidity and Interstage Hemodynamics Following Stage I Palliation in Patients with Turner Syndrome and Hypoplastic Left Heart Syndrome.

BACKGROUND: Turner syndrome (TS) is associated with left-sided cardiac lesions, including hypoplastic left heart syndrome (HLHS). Mortality as high as 80-90% has been reported following stage I single-ventricle palliation (S1P) in patients with TS and HLHS (TS + HLHS). The specific factors that relate to poor outcomes are not well understood. METHODS: This is a single-center, retrospective cohort study that includes 197 patients with HLHS who underwent S1P between 2008 and 2022. The clinical outcomes and interstage hemodynamics of TS + HLHS patients (N = 11) were compared with HLHS without TS (TS-HLHS), (N = 186). RESULTS: Of the 11 TS + HLHS patients, 10 underwent S1P; 4 underwent Glenn and 1 had hemodynamics considered prohibitive for Glenn; only 1 survived to Fontan palliation. Post-S1P mortality was higher in TS + HLHS (60 v 25%, p = 0.017). Following S1P, TS + HLHS had higher rates of postoperative ECMO (70 v 28%, p = 0.006), surgical necrotizing enterocolitis (20 v 3%, p = 0.007), peritoneal drain placement (70 v 31%, p = 0.012), urinary tract infection (30 v 9%, p = 0.035), and ICU readmissions (median 5 v 1, p = 0.035). Interstage hemodynamics demonstrated higher right ventricular end diastolic, (11 v 8mmHg, p = 0.033), mean pulmonary artery (20 v 13mmHg) (p = 0.002), and left atrial pressures (9 v 6mmHg, p = 0.047) in TS + HLHS. CONCLUSION: High mortality rates are described in TS + HLHS patients following S1P. In our cohort, despite most surviving more than 30 days post-S1P, long-term survival remained poor. Interstage catheterization data suggest poor physiologic candidacy for subsequent stages of single-ventricle palliation. Understanding the clinical and hemodynamic factors related to poor outcomes in TS + HLHS will help inform management for this population.

Increase in nuclear cell-free DNA is associated with major adverse events in adult and pediatric heart transplant recipients.

BACKGROUND: Cell-free DNA is an emerging biomarker. While donor fraction may detect graft events in heart transplant recipients, the prognostic value of total nuclear cell-free DNA (ncfDNA) itself is largely unexplored. OBJECTIVE: Explore the relationship between ncfDNA and clinical events in heart transplant recipients. METHODS: We conducted a multi-center prospective study to investigate the value of cell-free DNA in non-invasive monitoring following heart transplantation. Over 4000 blood samples were collected from 388 heart transplant patients. Total ncfDNA and donor fraction were quantified. Generalized linear models with maximum likelihood estimation for repeated measures with subjects as clusters were used to explore the relationship of ncfDNA and major adverse events. Receiver operating characteristic curves were used to help choose cutpoints. RESULTS: A ncfDNA threshold (50 ng/ml) was identified that was associated with increased risk of major adverse events. NcfDNA was elevated in patients who suffered cardiac arrest, required mechanical circulatory support or died post heart transplantation as well as in patients undergoing treatment for infection. CONCLUSIONS: Elevated ncfDNA correlates with risk for major adverse events in adult and pediatric heart transplant recipients and may indicate a need for enhanced surveillance after transplant.

Relationship between donor fraction cell-free DNA and clinical rejection in heart transplantation.

BACKGROUND: Clinical rejection (CR) defined as decision to treat clinically suspected rejection with change in immunotherapy based on clinical presentation with or without diagnostic biopsy findings is an important part of care in heart transplantation. We sought to assess the utility of donor fraction cell-free DNA (DF cfDNA) in CR and the utility of serial DF cfDNA in CR patients in predicting outcomes of clinical interest. METHODS: Patients with heart transplantation were enrolled in two sequential, multi-center, prospective observational studies. Blood samples were collected for surveillance or clinical events. Clinicians were blinded to the results of DF cfDNA. RESULTS: A total of 835 samples from 269 subjects (57% pediatric) were included for this analysis, including 28 samples associated with CR were analyzed. Median DF cfDNA was 0.43 (IQR 0.15, 1.36)% for CR and 0.10 (IQR 0.07, 0.16)% for healthy controls (p < .0001). At cutoff value of 0.13%, the area under curve (AUC) was 0.82, sensitivity of 0.86, specificity of 0.67, and negative predictive value of 0.99. There was serial decline in DF cfDNA post-therapy, however, those with cardiovascular events (cardiac arrest, need for mechanical support or death) showed significantly higher levels of DF cfDNA on Day 0 (2.11 vs 0.31%) and Day 14 (0.51 vs 0.22%) compared to those who did not have such an event (p < .0001). CONCLUSION: DF cfDNA has excellent agreement with clinical rejection and, importantly, serial measurement of DF cfDNA predict clinically significant outcomes post treatment for rejection in these patients.

Impact of obesity on post-operative arrhythmias after congenital heart surgery in children and young adults.

BACKGROUND: Obesity increases the risk of post-operative arrhythmias in adults undergoing cardiac surgery, but little is known regarding the impact of obesity on post-operative arrhythmias after CHD surgery. METHODS: Patients undergoing CHD surgery from 2007 to 2019 were prospectively enrolled in the parent study. Telemetry was assessed daily, with documentation of all arrhythmias. Patients aged 2-20 years were categorised by body mass index percentile for age and sex (underweight <5, normal 5-85, overweight 85-95, and obese >95). Patients aged >20 years were categorised using absolute body mass index. We investigated the impact of body mass index category on arrhythmias using univariate and multivariate analysis. RESULTS: There were 1250 operative cases: 12% underweight, 65% normal weight, 12% overweight, and 11% obese. Post-operative arrhythmias were observed in 38%. Body mass index was significantly higher in those with arrhythmias (18.8 versus 17.8, p = 0.003). There was a linear relationship between body mass index category and incidence of arrhythmias: underweight 33%, normal 38%, overweight 42%, and obese 45% (p = 0.017 for trend). In multivariate analysis, body mass index category was independently associated with post-operative arrhythmias (p = 0.021), with odds ratio 1.64 in obese patients as compared to normal-weight patients (p = 0.036). In addition, aortic cross-clamp time (OR 1.007, p = 0.002) and maximal vasoactive-inotropic score in the first 48 hours (OR 1.03, p = 0.04) were associated with post-operative arrhythmias. CONCLUSION: Body mass index is independently associated with incidence of post-operative arrhythmias in children after CHD surgery.

Spatial N-glycomics of the human aortic valve in development and pediatric endstage congenital aortic valve stenosis.

Congenital aortic valve stenosis (AS) progresses as an obstructive narrowing of the aortic orifice due to deregulated extracellular matrix (ECM) production by aortic valve (AV) leaflets and leads to heart failure with no effective therapies. Changes in glycoprotein and proteoglycan distribution are a hallmark of AS, yet valvular carbohydrate content remains virtually uncharacterized at the molecular level. While almost all glycoproteins clinically linked to stenotic valvular modeling contain multiple sites for N-glycosylation, there are very few reports aimed at understanding how N-glycosylation contributes to the valve structure in disease. Here, we tested for spatial localization of N-glycan structures within pediatric congenital aortic valve stenosis. The study was done on valvular tissues 0-17 years of age with de-identified clinical data reporting pre-operative valve function spanning normal development, aortic valve insufficiency (AVI), and pediatric endstage AS. High mass accuracy imaging mass spectrometry (IMS) was used to localize N-glycan profiles in the AV structure. RNA-Seq was used to identify regulation of N-glycan related enzymes. The N-glycome was found to be spatially localized in the normal aortic valve, aligning with fibrosa, spongiosa or ventricularis. In AVI diagnosed tissue, N-glycans localized to hypertrophic commissures with increases in pauci-mannose structures. In all valve types, sialic acid (N-acetylneuraminic acid) N-glycans were the most abundant N-glycan group. Three sialylated N-glycans showed common elevation in AS independent of age. On-tissue chemical methods optimized for valvular tissue determined that aortic valve tissue sialylation shows both α2,6 and α2,3 linkages. Specialized enzymatic strategies demonstrated that core fucosylation is the primary fucose configuration and localizes to the normal fibrosa with disparate patterning in AS. This study identifies that the human aortic valve structure is spatially defined by N-glycomic signaling and may generate new research directions for the treatment of human aortic valve disease.

No survival benefit associated with waiting for non-lung donor heart transplants for adult recipients with congenital heart disease.

BACKGROUND: Adults with congenital heart disease (CHD) awaiting heart transplant (HT) have higher mortality and waitlist removal due to clinical deterioration than those without CHD. The selective use of non-lung donors (NLD) to recover donor pulmonary vasculature to assist in graft implantation may be a contributing factor and is supported by consensus statements despite the recent use of pericardium or graft material as an alternative in pulmonary vascular reconstruction. The impact of selecting NLD for CHD recipients on wait time and mortality has not been evaluated. METHODS/RESULTS: In the United Network for Organ Sharing (UNOS) Registry, 1271 HT recipients age ≥ 18 with CHD were identified between 1987 and 2016, 68% of which had NLDs. Prior to HT, NLD recipients were significantly less likely to be listed UNOS Status 1A, require mechanical ventilation, or intra-aortic balloon pump support. There was no difference in mean waitlist time (254 vs. 278 days, p = .31), 1-year mortality (82% vs. 80%, p = .81; adjusted odds ratio 1.32, 95% confidence interval [CI] 0.96-1.83, p = .08), or overall mortality (adjusted hazard ratio 1.08, 95% CI 0.86-1.36, p = .48) between recipients from NLD and concomitant lung donors. CONCLUSIONS: Adult CHD patients who are less critically ill or listed at a lower status are more likely to receive HT from NLD. There is no overall mortality benefit associated with this practice. While specific cases may necessitate waiting for NLD, programs need to re-evaluate whether this should remain a more widespread practice among CHD patients.

Endothelial-Dependent Vasomotor Dysfunction in Infants After Cardiopulmonary Bypass.

OBJECTIVES: Cardiopulmonary bypass-induced endothelial dysfunction has been inferred by changes in pulmonary vascular resistance, alterations in circulating biomarkers, and postoperative capillary leak. Endothelial-dependent vasomotor dysfunction of the systemic vasculature has never been quantified in this setting. The objective of the present study was to quantify acute effects of cardiopulmonary bypass on endothelial vasomotor control and attempt to correlate these effects with postoperative cytokines, tissue edema, and clinical outcomes in infants. DESIGN: Single-center prospective observational cohort pilot study. SETTING: Pediatric cardiac ICU at a tertiary children's hospital. PATIENTS: Children less than 1 year old requiring cardiopulmonary bypass for repair of a congenital heart lesion. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Laser Doppler perfusion monitoring was coupled with local iontophoresis of acetylcholine (endothelium-dependent vasodilator) or sodium nitroprusside (endothelium-independent vasodilator) to quantify endothelial-dependent vasomotor function in the cutaneous microcirculation. Measurements were obtained preoperatively, 2-4 hours, and 24 hours after separation from cardiopulmonary bypass. Fifteen patients completed all laser Doppler perfusion monitor (Perimed, Järfälla, Sweden) measurements. Comparing prebypass with 2-4 hours postbypass responses, there was a decrease in both peak perfusion (p = 0.0006) and area under the dose-response curve (p = 0.005) following acetylcholine, but no change in responses to sodium nitroprusside. Twenty-four hours after bypass responsiveness to acetylcholine improved, but typically remained depressed from baseline. Conserved endothelial function was associated with higher urine output during the first 48 postoperative hours (R = 0.43; p = 0.008). CONCLUSIONS: Cutaneous endothelial dysfunction is present in infants immediately following cardiopulmonary bypass and recovers significantly in some patients within 24 hours postoperatively. Confirmation of an association between persistent endothelial-dependent vasomotor dysfunction and decreased urine output could have important clinical implications. Ongoing research will explore the pattern of endothelial-dependent vasomotor dysfunction after cardiopulmonary bypass and its relationship with biochemical markers of inflammation and clinical outcomes.

Sedated Echocardiograms Better Characterize Branch Pulmonary Arteries Following Bidirectional Glenn Palliation with Minimal Risk of Adverse Events.

Patients post-bidirectional Glenn (BDG) operation are at risk of left and right pulmonary artery (LPA and RPA) hypoplasia. Transthoracic echocardiograms (TTE) in active children can miss essential elements of anatomy. Procedural sedation improves image quality but increases risk of adverse events. We hypothesized that echocardiograms performed with sedation in patients post-BDG would improve visualization of branch pulmonary arteries with minimal adverse events. Patients post-BDG between 2007-2016 were identified. Exclusion criteria were > 12 months of age, absence of complete TTE before discharge, death before discharge, conversion to shunt physiology, and prolonged post-operative course > 7 weeks. Of 254 post-BDG patients, 153 met inclusion/exclusion criteria. TTE reports were reviewed for visualization of LPA/RPA and hypoplasia of LPA/RPA. Blinded assessment of image quality was performed (scale of 1[poor] to 5[excellent]). Pertinent clinical data were recorded. Pearson's chi-squared and Wilcoxon Rank Sum tests used for statistical analysis. The median age at surgery and hospital stay were 4.8 months and 10 days. Twenty-three patients underwent sedated TTE (15%). Sedated TTE significantly improved visualization of the RPA (100% vs 82%, p = 0.029) and LPA, though this did not reach statistical significance (100% vs 91%, p = 0.129). Sedated TTEs has significantly better image quality (median of 4 vs 3, p < 0.001). There were no serious adverse events due to sedation. Sedated TTE early post-BDG is safe, improves visualization of the RPA and LPA, and improves overall image quality. Routine sedated TTE in these patients should be considered. Implications for long-term outcome need to be further analyzed.

Direct Splanchnic Perfusion Safely Avoids Deep Hypothermia.

Deep hypothermia for the operative correction of congenital cardiac lesions protects hypoperfused organs, mostly because of its effect on lowering metabolic demand and oxygen requirement. Deleterious cerebral and extracranial side effects of deep hypothermia itself calls for a reexamination of the therapeutic value of hypothermia, and has led to the development of alternative perfusion strategies. Here we describe the potential advantages of milder hypothermia over deep hypothermia and our method of a practical and reproducible implementation of multisite perfusion under mild hypothermia (32°C).

Advances in MALDI imaging mass spectrometry of proteins in cardiac tissue, including the heart valve.

Significant progress has been made for tissue imaging of proteins using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI IMS). These advancements now facilitate mapping of a wide range of proteins, peptides, and post-translational modifications in a wide variety of tissues; however, the use of MALDI IMS to detect proteins from cardiac tissue is limited. This review discusses the most recent advances in protein imaging and demonstrates application to cardiac tissue, including the heart valve. Protein imaging by MALDI IMS allows multiplexed histological mapping of proteins and protein components that are inaccessible by antibodies and should be considered an important tool for basic and clinical cardiovascular research. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

Hypoplastic Left Heart Syndrome Sequencing Reveals a Novel NOTCH1 Mutation in a Family with Single Ventricle Defects.

Hypoplastic left heart syndrome (HLHS) has been associated with germline mutations in 12 candidate genes and a recurrent somatic mutation in HAND1 gene. Using targeted and whole exome sequencing (WES) of heart tissue samples from HLHS patients, we sought to estimate the prevalence of somatic and germline mutations associated with HLHS. We performed Sanger sequencing of the HAND1 gene on 14 ventricular (9 LV and 5 RV) samples obtained from HLHS patients, and WES of 4 LV, 2 aortic, and 4 matched PBMC samples, analyzing for sequence discrepancy. We also screened for mutations in the 12 candidate genes implicated in HLHS. We found no somatic mutations in our HLHS cohort. However, we detected a novel germline frameshift/stop-gain mutation in NOTCH1 in a HLHS patient with a family history of both HLHS and hypoplastic right heart syndrome (HRHS). Our study, involving one of the first familial cases of single ventricle defects linked to a specific mutation, strengthens the association of NOTCH1 mutations with HLHS and suggests that the two morphologically distinct single ventricle conditions, HLHS and HRHS, may share a common molecular and cellular etiology. Finally, somatic mutations in the LV are an unlikely contributor to HLHS.

MALDI Imaging Mass Spectrometry as a Lipidomic Approach to Heart Valve Research.

BACKGROUND: Valvular disease is characterized in part by lipid deposition, but systematic analysis of the patterns of global lipid expression in healthy and diseased valve tissues are unknown. This is due in part to tissue limitations for lipidomic preparations and technologies for evaluating lipid distribution in tissues. The study aim was to examine the application of matrixassisted laser desorption ionization imaging mass spectrometry (MALDI IMS) to the aortic valve during development and disease, as an approach to detect and map lipids and ultimately better understand valve structure and function. METHODS: Established MALDI IMS strategies were applied to thin tissue sections of heart valves to map lipids to corresponding morphological features. Healthy prenatal and adult ovine aortic valve tissues were evaluated using the developed techniques. Lipid expression levels were compared between prenatal and adult valves using Wilcoxon rank sum testing and area under the receiver operating curves. A classification algorithm was used to determine distinct lipid signatures in adult extracellular matrix (ECM) substructures, including fibrosa and spongiosa layers. Lipid patterns were examined in heart valve tissue from pediatric patients with congenital aortic valve stenosis (CAVS). RESULTS: Lipid levels were decreased in adult ovine aortic valves when compared with prenatal valves. Classification algorithms applied to lipid signatures reported distinct lipid signatures mapping to ECM substructures in the adult aortic valve, but could not distinguish amorphous structures at pre-natal day 5. In CAVS, the in-situ lipid aggregation of distinct lipid species showed unique patterning both concurrent and divergent with ECM disarray. Fatty acid content varied between normal and diseased human aortic valves. CONCLUSIONS: MALDI IMS provides a new and useful approach to evaluate lipid biology in heart valve tissue. These findings define a role for lipid regulation in aortic valve development and demonstrate patterns of lipid deregulation in congenital disease.

Association of blood products administration during cardiopulmonary bypass and excessive post-operative bleeding in pediatric cardiac surgery.

Our objectives were to study risk factors and post-operative outcomes associated with excessive post-operative bleeding in pediatric cardiac surgeries performed using cardiopulmonary bypass (CPB) support. A retrospective observational study was undertaken, and all consecutive pediatric heart surgeries over 1 year period were studied. Excessive post-operative bleeding was defined as 10 ml/kg/h of chest tube output for 1 h or 5 ml/kg/h for three consecutive hours in the first 12 h of pediatric cardiac intensive care unit (PCICU) stay. Risk factors including demographics, complexity of cardiac defect, CPB parameters, hematological studies, and post-operative morbidity and mortality were evaluated for excessive bleeding. 253 patients were studied, and 107 (42 %) met the criteria for excessive bleeding. Bayesian model averaging revealed that greater volume of blood products transfusion during CPB was significantly associated with excessive bleeding. Multiple logistic regression analysis of blood products transfusion revealed that increased volume of packed red blood cells (PRBCs) administration for CPB prime and during CPB was significantly associated with excessive bleeding (p = 0.028 and p = 0.0012, respectively). Proportional odds logistic regression revealed that excessive bleeding was associated with greater time to achieve negative fluid balance, prolonged mechanical ventilation, and duration of PCICU stay (p < 0.001) after adjusting for multiple parameters. A greater volume of blood products administration, especially PRBCs transfusion for CPB prime, and during the CPB period is associated with excessive post-operative bleeding. Excessive bleeding is associated with worse post-operative outcomes.

Acetaminophen attenuates lipid peroxidation in children undergoing cardiopulmonary bypass.

OBJECTIVE: Hemolysis, occurring during cardiopulmonary bypass, is associated with lipid peroxidation and postoperative acute kidney injury. Acetaminophen inhibits lipid peroxidation catalyzed by hemeproteins and in an animal model attenuated rhabdomyolysis-induced acute kidney injury. This pilot study tests the hypothesis that acetaminophen attenuates lipid peroxidation in children undergoing cardiopulmonary bypass. DESIGN: Single-center prospective randomized double-blinded study. SETTING: University-affiliated pediatric hospital. PATIENTS: Thirty children undergoing elective surgical correction of a congenital heart defect. INTERVENTIONS: Patients were randomized to acetaminophen (OFIRMEV [acetaminophen] injection; Cadence Pharmaceuticals, San Diego, CA) or placebo every 6 hours for four doses starting before the onset of cardiopulmonary bypass. MEASUREMENT AND MAIN RESULTS: Markers of hemolysis, lipid peroxidation (isofurans and F2-isoprostanes), and acute kidney injury were measured throughout the perioperative period. Cardiopulmonary bypass was associated with a significant increase in free hemoglobin (from a prebypass level of 9.8 ± 6.2 mg/dL to a peak of 201.5 ± 42.6 mg/dL postbypass). Plasma and urine isofuran and F2-isoprostane concentrations increased significantly during surgery. The magnitude of increase in plasma isofurans was greater than the magnitude in increase in plasma F2-isoprostanes. Acetaminophen attenuated the increase in plasma isofurans compared with placebo (p = 0.02 for effect of study drug). There was no significant effect of acetaminophen on plasma F2-isoprostanes or urinary makers of lipid peroxidation. Acetaminophen did not affect postoperative creatinine, urinary neutrophil gelatinase-associated lipocalin, or prevalence of acute kidney injury. CONCLUSION: Cardiopulmonary bypass in children is associated with hemolysis and lipid peroxidation. Acetaminophen attenuated the increase in plasma isofuran concentrations. Future studies are needed to establish whether other therapies that attenuate or prevent the effects of free hemoglobin result in more effective inhibition of lipid peroxidation in patients undergoing cardiopulmonary bypass.

Hybrid Stenting of Pulmonary Venous Baffle Stenosis: Subxiphoid Approach in Transposition of the Great Arteries.

A 31-year-old woman with transposition of the great arteries status post-Senning operation presents with severe pulmonary venous baffle obstruction. Both standards of care (percutaneous stenting or open repair) were deemed suboptimal and/or high risk. A multidisciplinary, hybrid approach via subxiphoid incision, guided by 3-dimensional modeling, provided a lower risk and minimally invasive intervention.

Management of Ebstein Anomaly in the Current Era: The Story of One Fetus and the Collaboration of Many-A Case Report.

Collaborative multicenter research has significantly increased our understanding of fetal Ebstein anomaly, delineating risk factors for adverse outcomes as well as predictors of postnatal management. These data are incorporated into prenatal care and therapeutic strategies and inform family counseling and delivery planning to optimize care. This report details the translation of findings from multicenter studies into multidisciplinary prenatal care for a fetus with Ebstein anomaly, supraventricular tachycardia, and a circular shunt, including transplacental therapy to control arrhythmias and achieve ductal constriction, informed and coordinated delivery room management, and planned univentricular surgical palliation.

Severe aortopulmonary collaterals are associated with lower transplant-free survival in patients undergoing staged single ventricle palliation.

Objective: To identify risk factors for aortopulmonary collateral (APC) development and assess the impact of severe APCs in children undergoing staged single ventricle palliation. Methods: Children undergoing a bidirectional Glenn operation between January 1, 2016, and March 31, 2021, at our center were included. All underwent angiography prior to Glenn and Fontan; APC flow was graded on a scale of 0 (no appreciable collateral flow) to 4 (severe burden). Demographic data, congenital diagnosis, clinical history, and outcomes were stratified by Glenn assessment; Fontan outcomes were stratified by pre-Fontan grade. Results: Sixty patients met the inclusion criteria, all of whom had angiographic evidence of APCs. There were 7 transplants and 9 deaths in the cohort. There were no significant differences in demographics among the patients. Right ventricular morphology was more common in patients with severe pre-Glenn collaterals (24 of 44 vs 2 of 6 vs 7 of 8; P = .014). Longer stage 1 aortic cross-clamp duration was associated with greater severity pre-Glenn (44 minutes vs 34 minutes vs 66 minutes; P = .023). Patients with grade 3 pre-Glenn collaterals more commonly required transplantation than those with grade 1 collaterals (P < .001) and had lower overall transplant-free survival than those with grade 1 (P = .005) or grade 2 (P = .04) collaterals. Conclusions: The ubiquity of APCs in this study demonstrates their prevalence in single ventricle disease. Right ventricular morphology and prolonged aortic cross-clamp duration are associated with higher burden. Greater severity was associated with decreased transplant-free survival. These data emphasize the negative long-term impact of these collaterals.