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The long-term impact of altered hemodynamics after stage II in children with hypoplastic left heart syndrome (HLHS) and hypoplastic left heart complex (HLHC) on cerebral growth and neurodevelopmental outcome is unknown. We aimed to investigate whether elevated central venous and atrial filling pressures before the Fontan procedure may be associated with smaller brain volumes and poorer neurodevelopmental outcome after the initial hybrid procedure. In a two-center cohort study semiautomated segmentation of cerebral magnetic resonance imaging scans was conducted in 25 children with HLHS/HLHC (25 hybrid) before the Fontan procedure (27.6 ± 4.3 months) and in 8 healthy control subjects (29.7 ± 9.5 months). Study patients were evaluated with the Bayley Scales of Infant and Toddler Development III (Bayley-III) and a neurologic examination. Hemodynamic measures after stage II were assessed with cardiac catheterization at 2 years of age before Fontan completion. Children with known genetic comorbidities were excluded. In HLHS/HLHC patients higher atrial filling pressures (6 ± 3 mm Hg; range, 2–14) were correlated with reduced brain volumes and lower language composite score, whereas higher Glenn pressures (10 ± 3 mm Hg; range, 6–16) were related to higher cerebrospinal fluid, reduced brain volumes, and lower cognitive, language, and motoric composite scores in the Bayley-III. Compared with control subjects white matter volumes were reduced and cerebrospinal fluid volumes increased in study patients. These data suggest that altered cardiovascular hemodynamics after stage II influence brain growth and neurodevelopmental outcome in infants with HLHS/HLHC. [ABSTRACT FROM AUTHOR]

Objectives: We sought to test the hypothesis that interventional atrial septal defect (ASD) closure can be performed safely and effectively using a bioresorbable occluder matrix. Background: The ideal septal occluder scaffold should promote the healthiest and most complete healing response while eventually facilitating the full resorption of the material and leaving “native” tissue behind, thus minimizing the potential for future complications from chronic foreign body and maintaining the possibility for later unobstructed transseptal access to the left atrium. Methods: The STARFlex occluders (NMT Medical Inc., Boston, Massachusetts) were modified by substituting the conventional polyester fabric for a bioengineered, acellular type-I collagen matrix derived from porcine submucosa with a heparin-coated surface (BioSTAR occluder, NMT Medical Inc.). Comparative transcatheter closure of ASDs was performed in young sheep (n = 36). Gross pathology and histopathology were obtained after follow-up periods ranging from 7 days to 2 years. Results: The STARFlex (control) devices were encapsulated time-dependently by ingrown fibrous tissue. Histology showed a mild but chronically persisting foreign body reaction. By contrast, BioSTAR devices exhibited a mild-to-moderate transient cellular immune response. Heparin coating of the BioSTAR surface improved the biocompatibility of the device by reducing surface thrombogencity. A remodeling process of the collagen scaffold, starting after 30 days in vivo, resulted in the full replacement of the matrix by host tissue after 2 years of follow-up. Conclusions: The BioSTAR device is the first septal occluder with a totally bioresorbable matrix that is fully replaced by host tissue during the healing process. The promising results of this study support testing of the BioSTAR device in clinical trials. [Copyright &y& Elsevier]

We report a 20-year-old patient with Shone's complex and severe diastolic dysfunction of his small left ventricle (LV) in whom severe pulmonary hypertension and biventricular failure developed while he was awaiting combined heart-lung transplantation. We performed a percutaneous balloon atrial septostomy and a modified Potts shunt (13-mm graft from left pulmonary artery to descending aorta), with the aim of decompressing the hypertensive right ventricle (RV) by reducing left ventricular preload and left atrial hypertension. The procedures were uneventful. The patient's condition improved rapidly and biventricular function was restored. In contrast to a Potts shunt in other conditions, patients with pulmonary hypertension caused by left ventricular disease may benefit from an additional atrial left-to-right shunt. [ABSTRACT FROM AUTHOR]

Cardiomyocyte maturation during pre- and postnatal development requires multiple intertwined processes, including a switch in energy generation from glucose utilization in the embryonic heart towards fatty acid oxidation after birth. This is accompanied by a boost in mitochondrial mass to increase capacities for oxidative phosphorylation and ATP generation required for efficient contraction. Whether cardiomyocyte differentiation is paralleled by augmented capacities to deal with reactive oxygen species (ROS), physiological byproducts of the mitochondrial electron transport chain (ETC), is less clear. Here we show that expression of genes and proteins involved in redox homeostasis and protein quality control within mitochondria increases after birth in the mouse and human heart. Using primary embryonic, neonatal and adult mouse cardiomyocytes in vitro we investigated how excessive ROS production induced by mitochondrial dysfunction affects cell survival and stress response at different stages of maturation. Embryonic and neonatal cardiomyocytes largely tolerate inhibition of ETC complex III by antimycin A (AMA) as well as ATP synthase (complex V) by oligomycin but are susceptible to complex I inhibition by rotenone. All three inhibitors alter the intracellular distribution and ultrastructure of mitochondria in neonatal cardiomyocytes. In contrast, adult cardiomyocytes treated with AMA undergo rapid morphological changes and cellular disintegration. At the molecular level embryonic cardiomyocytes activate antioxidative defense mechanisms, the integrated stress response (ISR) and ER stress but not the mitochondrial unfolded protein response upon complex III inhibition. In contrast, adult cardiomyocytes fail to activate the ISR and antioxidative proteins following AMA treatment. In conclusion, our results identified fundamental differences in cell survival and stress response in differentiated compared to immature cardiomyocytes subjected to mitochondrial dysfunction. The high stress tolerance of immature cardiomyocytes might allow outlasting unfavorable intrauterine conditions thereby preventing fetal or perinatal heart disease and may contribute to the regenerative capacity of the embryonic and neonatal mammalian heart. [Display omitted] • Capacities for redox homeostasis increase parallel to cardiomyocyte maturation. • Embryonic and neonatal cardiomyocytes largely tolerate mitochondrial dysfunction. • The site of mitochondrial ROS generation determines outcome in immature cardiomyocytes. • Adult cardiomyocytes are highly susceptible to mitochondrial dysfunction. • Cardiomyocyte maturation alters the molecular response to mitochondrial impairment. [ABSTRACT FROM AUTHOR]

Single ventricle (SV) patients with a Fontan circulation are at risk for functional deterioration. The aim of this study was to assess longitudinal Fontan hemodynamics using serial cardiovascular magnetic resonance (CMR) data and to study the impact of aortopulmonary collateral (APC) flow and type of SV morphology. Forty-one Fontan patients (age at first CMR 13.4 ± 6.0 years) with two CMR examinations within a time interval of at least 4 years (follow-up 5.3 ± 0.9 years) were included. The protocol consisted of short-axis cine volumetry and 2-dimensional blood flow measurements in the inferior vena cava (IVC), superior vena cava (SVC) and ascending aorta (Ao). APC flow was calculated as Ao – (SVC + IVC). Myocardial strain/strain rate was assessed using feature tracking technique. SV end-diastolic volume (p = 0.14) and ejection fraction (p = 0.70) remained constant. No significant changes in CMR derived myocardial strain/strain rate values were observed. Ao flow decreased (p = 0.01), IVC flow remained unchanged (p = 0.52), while SVC flow (p = 0.003) and APC flow (p = 0.006) decreased significantly. Patients with a systemic right ventricle (RV) showed unchanged APC flow and a further increase in SV size over time compared to patients with a systemic left ventricle. Longitudinal CMR data in a cohort of clinically stable Fontan patients revealed no significant changes in SV dimensions and myocardial performance while APC flow decreased spontaneously. Patients with a systemic RV seem to be at risk for permanent SV volume overload through APCs and might therefore benefit from consequent interventional APC embolization. • In a clinically stable Fontan cohort SV size and function remained unchanged after 4-year follow-up. • APC flow decreased spontaneously in the entire study population. • The group with a systemic RV showed unchanged APC flow and progressive SV dilatation. • Systemic RV patients may therefore benefit from consequent interventional APC embolization. [ABSTRACT FROM AUTHOR]

Background: The surgical creation of a Potts shunt has been reported in children with suprasystemic idiopathic pulmonary artery (PA) hypertension (IPAH) refractory to any medical therapy. This surgical approach allows acute decompression of the right ventricle (RV) and thereby avoids ventricular failure. We present 4 newborns and infants with different causes of pulmonary hypertension (PH) in whom interventional stenting of the patent ductus arteriosus (PDA) was used to create a “functional” Potts shunt. Methods: Suprasystemic PH was diagnosed by cardiac catheterization in 2 newborns with complex left heart obstructive lesions, a patient with persistent PH of the newborn (PPHN), and an infant with IPAH and was accompanied by RV dilation and imminent RV failure. Results: Stenting of the PDA was performed uneventfully during cardiac catheterization in all patients and led to stabilization of clinical symptoms. The 2 patients with complex cardiac lesions subsequently underwent successful biventricular repair. In the PPHN patient, the stented PDA was closed interventionally when PA pressures dropped and a significant left-to-right shunt occurred. PA pressures in the patient with IPAH remained high while the stented PDA still served as RV decompression in avoidance of lung transplantation. Conclusions: Newborns and infants with suprasystemic PH of varying etiologies may benefit from the creation of a functional Potts shunt by stenting the PDA. This strategy should be considered in patients with suprasystemic IPAH or PPHN as a temporary or permanent therapy when a PDA can be identified at cardiac catheterization. It may also be beneficial in patients with PH due to left heart obstructions by serving as a bridge to further corrective surgery. [Copyright &y& Elsevier]

Background: Dilated cardiomyopathy (DCM) in childhood has a considerable morbidity and mortality and high incidence of heart transplantation. Pulmonary artery banding (PAB) has been proposed in patients with corrected transposition of the great arteries to retrain the sub-pulmonic left ventricle (LV) and to improve a failing sub-aortic right ventricle. We evaluated the short-term and medium-term effects of PAB in young patients with LVDCM. Methods: A retrospective single-center observational study was performed to evaluate the possible benefits of a dilatable surgical PAB in infants and young children with LVDCM. Results: Reported are 12 patients (10 infants, 2 toddlers) with LVDCM referred for heart transplant who received a surgical PAB. There were no hospital deaths. Clinical functional status improved in all patients. The pressure gradient across the PAB increased within 20 days from 28 ± 7 to 43 ± 15 mm Hg. The LV ejection fraction increased from 14.5% ± 5% pre-PAB to 27% ± 13% at hospital discharge and to 47% ± 10% at 3 to 6 months. The LV end-diastolic diameter (z-score) decreased (p > 0.001) from 46 ± 6.1 (+7.0 ± 1.3) to 35 ± 15 mm (+3.0 ± 1.3) after 3 to 6 months and to 34 ± 15 mm (+1.3 ± 1.14) after a median age of 2 years (maximum 6.6 years), respectively. Plasma B-type natriuretic peptide levels decreased from 3431 ± 2610 to 288 ± 321 pg/ml at discharge and to 102 ± 96 pg/ml 22 months later. Eight children were subsequently de-banded by transcatheter technique and 6 of them are currently at Ross Heart Failure Classification for Children class I. Two patients, both with non-compaction DCM, deteriorated at 5 and 6 months after PAB debanding and finally died. Conclusion: In young children with LVDCM and still-preserved right ventricular function, PAB led to an improvement of LV and mitral valve function by ventricular interaction. [ABSTRACT FROM AUTHOR]

Objectives The purpose of our study was to assess pulmonary endothelial function by vasodilator response to acetylcholine (Ach) administered in segmental pulmonary arteries in children with idiopathic pulmonary arterial hypertension (IPAH). We hypothesized that there was a relationship among pulmonary endothelial response to Ach, severity of the disease, and clinical outcome. Background IPAH may be associated with pulmonary endothelial dysfunction; however, data regarding the impact of endothelial dysfunction on severity and prognosis of this disease are limited. Methods Forty-three children and adolescents (mean age: 10.4 ± 5.5 years) with IPAH were included in the study. Changes in pulmonary blood flow in response to Ach were determined using intravascular Doppler flow measurements. Pulmonary flow reserve (PFR) was calculated as the ratio of pulmonary blood flow velocity in response to Ach relative to baseline values. Results Mean PFR of all patients was 1.58 ± 0.67. Mean follow-up after catheterization was 55.7 ± 41.9 months. Freedom from serious cardiovascular events (lung transplantation or death) was 83% after 2 years, 76% after 3 years, and 57% after 5 years. PFR was related significantly to World Health Organization functional class. Receiver-operating characteristic curves revealed a PFR of 1.4 as the best cutoff value. Kaplan-Meier analysis demonstrated that a PFR of <1.4 was highly predictive for cardiovascular events (log-rank [Mantel Cox] chi-square: 12.49, p < 0.0001). Conclusions Our study demonstrates a strong relationship between pulmonary endothelial response to Ach and prognosis of children with IPAH. As an adjunct to the usual testing protocol, this method provides additional information for therapeutic guidance. [ABSTRACT FROM AUTHOR]

Novel surgical strategies have dramatically improved the initial outcome of newborns with hypoplastic left heart syndrome. However, the single systemic right ventricle remains a major challenge, with limited effectiveness of pharmacologic therapy. The present case documents that the intracoronary administration of autologous bone marrow-derived progenitor cells is technically feasible in a critically ill infant with hypoplastic left heart syndrome and severe heart failure after a hybrid comprehensive stage II procedure. Cell therapy might represent an option before heart transplantation in children with single ventricle physiology presenting with severe heart failure. [Copyright &y& Elsevier]