Chronic Maternal Hyperoxygenation and Effect on Cerebral and Placental Vasoregulation and Neurodevelopment in Fetuses with Left Heart Hypoplasia.

INTRODUCTION: In a pilot study of chronic maternal hyperoxygenation (CMH) in left heart hypoplasia (LHH), we sought to determine effect estimates of CMH on head size, vascular resistance indices, and neurodevelopment compared to controls. MATERIAL AND METHODS: Nine gravidae meeting the inclusion criteria (fetal LHH, ≥25.9 weeks' gestation, and ≥10% increase in percent aortic flow after acute hyperoxygenation) were prospectively enrolled. Controls were 9 contemporary gravidae with fetal LHH without CMH. Brain growth and Doppler-derived estimates of fetal cerebrovascular and placental resistance were blindly evaluated and compared using longitudinal regression. Postnatal anthropomorphic and neurodevelopmental assessments were compared. RESULTS: There was no difference in baseline fetal measures between groups. There was significantly slower biparietal diameter (BPD) growth in the CMH group (z-score change -0.03 ± 0.02 vs. +0.09 ± 0.05 units/week, p = 0.02). At 6 months postnatal age, the mean head circumference z-score in the CMH group was smaller than that of controls (-0.20 ± 0.58 vs. +0.85 ± 1.11, p = 0.048). There were no differences in neurodevelopmental testing at 6 and 12 months. DISCUSSION: In this pilot study, relatively diminished fetal BPD growth and smaller infant head circumference z-scores at 6 months were noted with in utero CMH exposure.

Anomalous origin of the left coronary artery from the right pulmonary artery in a univentricular heart.

Anomalous origin of the left coronary artery from the right pulmonary artery in single ventricles is a very rare congenital anomaly. Failure to recognise it preoperatively may lead to adverse outcomes, including death. We report the case of a neonate with a univentricular heart in the form of a double-outlet right ventricle, mitral atresia with discrete coarctation of the aorta, and an incidental intraoperative finding of an anomalous origin of the left coronary artery from the right pulmonary artery. The patient underwent a successful repair with an uneventful postoperative course.

Prenatal diagnosis, hospital characteristics, and mortality in transposition of the great arteries.

BACKGROUND: The role of prenatal diagnosis in reducing neonatal mortality from transposition of the great arteries (TGA) is controversial. Factors affected by prenatal diagnosis such as proximity at birth to a cardiac surgical center (CSC) and CSC volume are associated with mortality in congenital heart disease. The purpose of the study was to determine the associations between prenatal diagnosis, distance from birthplace to a CSC, CSC TGA volume, and neonatal mortality in patients with TGA. METHODS: The Texas Birth Defects Registry was queried for all live born infants with TGA from 1999 to 2007. Four hundred sixty-eight cases of TGA were included. RESULTS: Forty-eight patients (10.3%) were prenatally diagnosed, and 20 patients died before age 28 days (4.3%). Neither prenatal diagnosis nor close proximity to a CSC at birth (p > 0.05) were associated with decreased mortality. Low CSC TGA volume was associated with increased mortality (p < 0.0002). Mortality at the CSCs with <5 patients per year was 9.6%; CSCs with 5 to 10 patients per year had 0% mortality, and those with >10 patients per year had 2.3% mortality. In multivariable logistic regression, only preterm birth (odds ratio, 7.05; 95% confidence interval, 4.13-12.05) and lower CSC volume (p < 0.001) were associated with neonatal mortality, although prenatal diagnosis attenuated the detrimental association of lower volume CSCs with higher mortality (p for interaction = 0.047). CONCLUSION: Lower CSC TGA patient volume was associated with higher neonatal mortality. Prenatal diagnosis may improve survival in lower volume CSCs. Birth Defects Research (Part A) 106:739-748, 2016. © 2016 Wiley Periodicals, Inc.

Polyarteritis nodosa in childhood: recognition of early dermatologic signs may prevent morbidity.

Systemic polyarteritis nodosa (PAN) is a vasculitis that affects small to medium-size arteries. Onset in childhood is rare and can cause significant morbidity. Often, cutaneous manifestations can provide early clues toward diagnosis. This article describes a case of childhood systemic PAN that presented with fever, a necrotic skin lesion, and oral ulceration. Intestinal perforation complicated this case. Prompt recognition of childhood PAN is important to prevent serious complications.

Al(III)/K(I) Heterodinuclear Polymerization Catalysts Showing Fast Rates and High Selectivity for Polyester Polyols.

Low molar mass, hydroxyl end-capped polymers, often termed "polyols," are widely used to make polyurethanes, resins, and coatings and as surfactants in liquid formulations. Epoxide/anhydride ring-opening copolymerization (ROCOP) is a controlled polymerization route to make them, and its viability depends upon catalyst selection. In the catalysis, the polyester polyol molar masses and end-groups are controlled by adding specific but excess quantities of diols (vs catalyst), known as the chain transfer agent (CTA), to the polymerizations, but many of the best current catalysts are inhibited or even deactivated by alcohols. Herein, a series of air-stable Al(III)/K(I) heterodinuclear polymerization catalysts show rates and selectivity at the upper end of the field. They also show remarkable increases in activity, with good selectivity and control, as quantities of diol are increased from 10-400 equiv. The reactions are accelerated by alcohols, and simultaneously, their use allows for the production of hydroxy telechelic poly/oligoesters (400 < Mn (g mol-1) < 20,400, D < 1.19). For example, cyclohexene oxide (CHO)/phthalic anhydride (PA) ROCOP, using the best Al(III)/K(I) catalyst with 200 equiv of diol, shows a turnover frequency (TOF) of 1890 h-1, which is 4.4× higher than equivalent reactions without any diol (Catalyst/Diol/PA/CHO = 1:10-400:400:2000, 100 °C). In all cases, the catalysis is well controlled and highly ester linkage selective (ester linkages >99%) and operates effectively using bicyclic and/or biobased anhydrides with bicyclic or flexible alkylene epoxides. These catalysts are recommended for future production and application development using polyester polyols.

Water-soluble polyphosphonate-based bottlebrush copolymers via aqueous ring-opening metathesis polymerization.

Ring-opening metathesis polymerization (ROMP) is a versatile method for synthesizing complex macromolecules from various functional monomers. In this work, we report the synthesis of water-soluble and degradable bottlebrush polymers, based on polyphosphoesters (PPEs) via ROMP. First, PPE-macromonomers were synthesized via organocatalytic anionic ring-opening polymerization of 2-ethyl-2-oxo-1,3,2-dioxaphospholane using N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide as the initiator and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the catalyst. The resulting norbornene-based macromonomers had degrees of polymerization (DPn) ranging from 25 to 243 and narrow molar mass dispersity (D ≤ 1.10). Subsequently, these macromonomers were used in ROMP with the Grubbs 3rd-generation bispyridyl complex (Ru-G3) to produce a library of well-defined bottlebrush polymers. The ROMP was carried out either in dioxane or in aqueous conditions, resulting in well-defined and water-soluble bottlebrush PPEs. Furthermore, a two-step protocol was employed to synthesize double hydrophilic diblock bottlebrush copolymers via ROMP in water at neutral pH-values. This general protocol enabled the direct combination of PPEs with ROMP to synthesize well-defined bottlebrush polymers and block copolymers in water. Degradation of the PPE side chains was proven resulting in low molar mass degradation products only. The biocompatible and biodegradable nature of PPEs makes this pathway promising for designing novel biomedical drug carriers or viscosity modifiers, as well as many other potential applications.

Synthesis of (µ2,η3-allyl-η5-oxapentadienyl)diiron pentacarbonyl complexes, an unusual reaction product from η4-(vinylketene)Fe(CO)3 complexes: structure and electron density distribution analysis.

The synthesis of a series of ferrocenylvinylketenes as stable η4-[Fe(CO)3] complexes (3a-f) was successfully accomplished through the reaction of η2-[Fe(CO)4] complexes under mild carbonylation conditions. The reactivity of 3a-f under thermal conditions afforded the unexpected formation of a novel family of (µ2,η3-allyl-η5-oxapentadienyl)diiron pentacarbonyl complexes 5a-f proposed to be formed by a sequence metathesis-haptotropic rearrangement between the starting η4-vinylketene iron(0) complex 3 and a η4-vinylcarbene iron(0) complex trapped in situ after a reversible carbonylation process favored by the thermal conditions. An electron density distribution analysis (EDD) of 5e using high-resolution X-ray diffraction data in combination with the DFT framework was performed to understand the electronic communication between the two iron fragments.

Iodine-promoted insertion of the oxygen atom from water in η4-vinylketene[Fe(CO)3] complexes.

Iodine promotes the in situ formation of iron(II) species from η4-vinylketene[Fe(CO)3] (3a-h) as a key intermediate for the synthesis of 2(5H)-furanones (4a-h) by a sequential water-insertion/carbon-oxygen coupling under mild reaction conditions. Compounds 4a-h were obtained in good to excellent yields. A possible reaction pathway was also proposed by DFT calculations. This methodology can be extended to the synthesis of (5H)-pyrrol-2-ones using anilines, with moderate yields and a few limitations.

Polyphosphonate-Based Macromolecular RAFT-CTA Enables the Synthesis of Well-Defined Block Copolymers Using Vinyl Monomers.

Reversible addition-fragmentation chain transfer (RAFT) polymerization has become a straightforward approach to block copolymers using a wide variety of functional vinyl monomers. Polyphosphoester (PPE) macroinitiators from ring-opening polymerization (ROP) of their corresponding cyclic phosphoesters have been previously prepared for atom transfer radical polymerization; however, to date, these biodegradable macroinitiators for RAFT polymerization have not been reported. Herein, a macromolecular RAFT-chain transfer agent (CTA) based on poly(ethyl ethylene phosphonate) was prepared by the organocatalytic ROP of 2-ethyl-2-oxo-1,3,2-dioxaphospholane using 2-cyano-5-hydroxypentan-2-yl dodecyl trithiocarbonate as the initiator and 1,8-diazabycyclo[5.4.0]undec-7-ene as the catalyst. Precise macro-CTAs of degrees of polymerization (DPn) from 34 to 70 with D ≤ 1.10 were prepared and used in the dioxane solution RAFT polymerization of acrylamide, acrylates, methacrylates, and 2-vinylpyridine to yield a library of well-defined block copolymers. Additionally, the PPE-based macro RAFT-CTA was used as a nonionic surfactant in a typical aqueous emulsion polymerization of styrene to produce well-defined nanoparticles with the hydrophilic PPEs on their surface as the stabilizing agent. This general protocol allowed the combination of polyphosphoesters with RAFT polymerization.

Successful Palliation via Kawashima Procedure of an Infant With Heterotaxy Syndrome and Left-Atrial Isomerism.

BACKGROUND: Heterotaxy is a condition of abnormal lateralization of organs across the body's left-right axis, causing multiple congenital malformations. The anatomic manifestations of heterotaxy syndrome generally follow one of two patterns, referred to as right atrial isomerism (with two similar right atria and duplication of right-sided features of multiple organs) and left atrial isomerism (with two similar left atria and duplication of left-sided features of multiple organs). Cardiac surgical intervention for patients with heterotaxy syndrome depends on ventricular physiology and circulatory balance. For patients with single-ventricle physiology, a Fontan operation, which directs systemic venous return to the pulmonary arteries, is the definitive intervention. Prior to a Fontan operation, many patients require one or more palliative surgeries (eg, a Blalock-Taussig-Thomas shunt or bidirectional Glenn/Kawashima procedure) to prepare them for definitive correction. CASE REPORT: We present the case of a term female neonate who was transferred to our pediatric cardiovascular intensive care unit for management of suspected congenital cardiac disease. Echocardiography confirmed the diagnosis of heterotaxy syndrome with left atrial isomerism, an interrupted inferior vena cava with azygos continuation, and a hypoplastic left ventricle with single-ventricle physiology. At 11 months of age, she underwent a Kawashima procedure with subtotal pulmonary artery ligation. She tolerated the procedure well and is anticipated to remain stable for the near future, possibly without the need for further cardiac surgery. CONCLUSION: Patients with heterotaxy syndrome have congenital malformations in several organ systems, requiring lifelong coordination of care among health providers across multiple disciplines.

Improvement in Cardiac Function With Enzyme Replacement Therapy in a Patient With Infantile-Onset Pompe Disease.

BACKGROUND: Pompe disease is a lysosomal storage disorder that results from an inborn error of metabolism involving abnormal glycogen storage. Infantile-onset Pompe disease is the most severe phenotype, and enzyme replacement therapy with alglucosidase alfa (Lumizyme) improves medical and functional outcomes in patients with infantile-onset Pompe disease. CASE REPORT: We report the case of a patient with infantile-onset Pompe disease who presented with severe hypertrophic cardiomyopathy, systolic and diastolic cardiac dysfunction, and hypotonia. She experienced significant improvement in cardiac systolic function while receiving enzyme replacement therapy. CONCLUSION: Typically, patients with infantile-onset Pompe disease and severe hypertrophic cardiomyopathy are not as responsive to enzyme replacement therapy as patients with mild or no hypertrophic cardiomyopathy. We demonstrated the efficacy of enzyme replacement therapy in a patient with severe hypertrophic cardiomyopathy.

Step-growth titanium-catalysed dehydropolymerisation of amine-boranes.

Precatalysts active for the dehydropolymerisation of primary amine-boranes are generally based on mid or late transition metal. We have found that the activity of the precatalyst system formed from CpR2TiCl2 and 2nBuLi towards the dehydrogenation of the secondary amine-borane Me2NH·BH3, to yield the cyclic diborazane [Me2N-BH2]2, increases dramatically with increasing electron-donating character of the cyclopentadienyl rings (CpR). Application of the most active precatalyst system (CpR = η-C5Me5) to the primary amine-borane MeNH2·BH3 enabled the first synthesis of high molar mass poly(N-methylaminoborane), [MeNH-BH2] n , the BN analogue of polypropylene, by an early transition metal such as catalyst. Significantly, unlike other dehydropolymerization precatalysts for MeNH2·BH3 such as [Ir(POCOP)H2], skeletal nickel, and [Rh(COD)Cl]2, the Ti precatalyst system was also active towards a range of substrates including BzNH2·BH3 (Bz = benzyl) yielding high molar mass polymer. Moreover, in contrast to the late transition metal catalysed dehydropolymerisation of MeNH2·BH3 and also the Ziegler-Natta polymerisation of olefins, studies indicate that the Ti-catalyzed dehydropolymerization reactions proceed by a step-growth rather than a chain-growth mechanism.

A population-based analysis of mortality in patients with Turner syndrome and hypoplastic left heart syndrome using the Texas Birth Defects Registry.

BACKGROUND: Hypoplastic left heart syndrome (HLHS) is strongly associated with Turner syndrome (TS); outcome data when these conditions coexist is sparse. We aimed to investigate long-term survival and causes of death in this population. METHODS: The Texas Birth Defects Registry was queried for all live born infants with HLHS during 1999-2007. We used Kaplan-Meier and Cox regression analyses to compare survival among patients with HLHS with TS (HLHS/TS+) to patients who had HLHS without genetic disorders or extracardiac birth defects (HLHS/TS-). RESULTS: Of the 542 patients with HLHS, 11 had TS (2.0%), 71 had other extracardiac birth defects or genetic disorders, and 463 had neither. The median follow-up time was 4.2 y (interquartile range [IQR] 2.1-6.5). Comparing those with HLHS/TS+ to HLHS/TS-, 100% versus 35% were female (P < .001), and median birth weight was 2140 g (IQR 1809-2650) versus 3196 g (IQR 2807-3540, P < .001). Neonatal mortality was 36% in HLHS/TS+ versus 27% in HLHS/TS- (log rank = 0.431). Ten of the 11 TS+ patients died during the study period for cumulative mortality of 91% versus 50% (hazard ratio (HR) for TS+: 2.90, 95% CI 1.53-5.48). Six patients died prior to surgery, 5 underwent Stage 1 palliation (S1P), 3 died after S1P, 2 survived past S2P, and one of these died at age 19 mo. The underlying cause of death was listed as congenital heart disease on all the death certificates of HLHS/TS+ patients. In multivariable analysis controlling for low birth weight (<2500 g), TS remained associated with significantly increased cumulative mortality, although females without TS had higher mortality than males (HR for TS+ versus males: 2.42, 95% CI 1.24-4.73; HR for TS- females versus males: 1.41, 95% CI 1.08-1.83). CONCLUSION: TS with HLHS is associated with significant mortality. The increased mortality in females without documented TS calls to question if TS is undetected in a portion of females with HLHS.

Titanium Plug Closure after HeartWare Ventricular Assist Device Explantation in a 15-Year-Old Girl: First U.S. Experience.

We describe the case of a teenage girl with anthracycline-induced cardiomyopathy who received a HeartWare ventricular assist device and underwent successful device explantation after cardiac recovery. During device support, the patient's cardiac function returned to normal. Twelve months after implantation, we explanted the device via repeat median sternotomy. To close the hole in the left ventricular apex and preserve the sewing ring in case future device support is needed, we used a German-manufactured titanium plug, developed specifically for this purpose. To our knowledge, this is the first use of this plug in the United States. The patient recovered uneventfully and was discharged from the hospital on postoperative day 11. Left ventricular biopsy specimens at explantation revealed the resolution of previous degenerative sarcomeric changes. Our patient did well clinically; however, recurrent late anthracycline cardiotoxicity might subsequently cause her cardiac function to deteriorate. In this event, our use of the titanium plug to preserve the left ventricular sewing ring would enable easier device replacement than would other explantation options.

Boron-nitrogen main chain analogues of polystyrene: poly(B-aryl)aminoboranes via catalytic dehydrocoupling.

The first high molar mass polyaminoboranes with an organic substituent at boron, namely the B-arylated polyaminoboranes [NH2-BHPh]n (2a) and [NH2-BH(p-CF3C6H4)]n (2b), have been prepared via catalytic dehydropolymerisation. These materials can be considered as inorganic analogues of polystyrene with a B-N main chain. Their synthesis was achieved from B-aryl amine-borane precursors in solution using an [IrH2(POCOP)] precatalyst.

Public health research in congenital heart disease.

Public health research is an integral part of the study of congenital heart disease. While this type of research has become more popular, particularly over the past decade, it has a history that stretches back to almost the beginnings of pediatric cardiology as a field. This review aims to introduce the concepts and methodologies of public health and how they relate to congenital heart disease, describe some of the challenges of traditional research methods in congenital heart disease, describe the history of public health research, and demonstrate the relevance of public health research, particularly databases, to pediatric cardiology fellows.

Systemic effects of intracoronary nitroglycerin during coronary angiography in children after heart transplantation.

Coronary spasm during coronary angiography for vasculopathy in children can be prevented by the intracoronary administration of nitroglycerin. We reviewed the anesthesia and catheterization reports and charts for pediatric transplant recipients who underwent angiography from 2005 through 2010. Correlation analysis was used to study the relation of post-injection systolic blood pressure (SBP) to nitroglycerin dose. Forty-one angiographic evaluations were performed on 25 patients (13 male and 12 female). Mean age was 9.9 ± 3.2 years (range, 3.3-16.1 yr). The mean total dose of nitroglycerin was 2.93 ± 1.60 µg/kg (range, 1-8 µg/kg). There was a significant drop between the baseline SBP (mean, 106 ± 21.6 mmHg) and the lowest mean SBP before nitroglycerin administration (78 ± 13.2, P <0.0001, paired t test). There was no significant additional change in SBP (mean after nitroglycerin administration, 80.7 ± 13.1 mmHg; P = 0.2). There was a significant drop in lowest heart rate between baseline (109 ± 16.5 beats/min) and before nitroglycerin administration (89 ± 14.3 beats/min; P <0.0001, paired t test). There was no significant additional change in heart rate (mean heart rate after nitroglycerin, 84 ± 17.7 beats/min; P = 0.09). There were 2 interventions for SBP before nitroglycerin and 2 after nitroglycerin. One child experienced a transient ST-T-segment change during angiography after nitroglycerin. In the highest dose range, the additional decrease in SBP was 7.2 mmHg (P=0.03). Routine intracoronary nitroglycerin administration in this dose range produced no significant changes in SBP or heart rate in children.