Early changes in ventricular septal defect size and ventricular geometry in the single left ventricle after volume-unloading surgery

Objectives.This study investigated the phenomenon of, and the relation between, alterations in ventricular geometry after acute surgical volume unloading of the ventricle and the development of subaortic stenosis in patients with a single ventricle and ventricular septal defect—dependent systemic flow.Background.Subaortic outflow obstruction has been observed to occur in patients with a single left ventricle after placement of a pulmonary artery band. The timing and etiology of this phenomenon are not well defined.Methods.The preoperative and postoperative echocardiograms of 18 patients 14.9 ± 22.8 months old (mean ± SD) with a diagnosis of single left ventricle who underwent pulmonary artery banding or cavopulmonary connection were reviewed. Postoperative studies were performed a mean of 7.0 ± 6.5 days after operation. The ventricular septal defect diameter was measured in two orthogonal views and the area calculated using the formula for an ellipse. Interventricular septal and posterior wall thickness and left ventricular diameter and length were also measured.Results.Mean ventricular septal defect area indexed to body surface area diminished by 36 ± 23% (3.1 ± 2.7 to 2.0 ± 1.8 cm2/m2, p < 0.01). Mean interventricular septal and posterior wall thickness increased significantly, and left ventricular diameter and length decreased significantly. A greater diminution in ventricular septal defect area was noted after cavopulmonary connection (41 ± 19%, p < 0.01) than after pulmonary artery banding (25 ± 28%, p = 0.22).Conclusions.In the single left ventricle, diminution in ventricular septal defect size occurs early and is related to an acute alteration in ventricular geometry that accompanies the decrease in ventricular volume. Ventricular septal defect diminution was greater after volume unloading of the ventricle after cavopulmonary connection than after pulmonary artery banding

Age-specific effects of childhood body mass index on multiple sclerosis risk

OBJECTIVE: Higher body mass index (BMI) during early life is thought to be a causal risk factor for multiple sclerosis (MS). We used longitudinal Mendelian randomisation (MR) to determine whether there is a critical window during which BMI influences MS risk. METHODS: Summary statistics for childhood BMI (n ~ 28,000 children) and for MS susceptibility were obtained from recent large genome-wide association studies (GWAS) (n = 14,802 MS, 26,703 controls). We generated exposure instruments for BMI during four non-overlapping age epochs (< 3 months, 3 months–1.5 years, 2–5 years, and 7–8 years) and performed MR using the inverse variance weighted method with standard sensitivity analyses. Multivariable MR was used to account for effects mediated via later-life BMI. RESULTS: For all age epochs other than birth, genetically determined higher BMI was associated with an increased liability to MS: Birth [Odds Ratio (OR) 0.81, 95% Confidence Interval (CI) 0.50–1.31, Number of Single-Nucleotide Polymorphisms (N(SNPs)) = 7, p = 0.39], Infancy (OR 1.18, 95% CI 1.04–1.33, N(SNPs) = 18, p = 0.01), Early childhood (OR 1.31, 95% CI 1.03–1.66, N(SNPs) = 4, p = 0.03), Later childhood (OR 1.34, 95% CI 1.08–1.66, N(SNPs) = 4, p = 0.01). Multivariable MR suggested that these effects may be mediated by effects on adult BMI. CONCLUSION: We provide evidence using MR that genetically determined higher BMI during early life is associated with increased MS risk. This effect may be driven by shared genetic architecture with later-life BMI. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00415-022-11161-4

Tracheostomy after Surgery for Congenital Heart Disease: An Analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

Background Information concerning tracheostomy after operations for congenital heart disease has come primarily from single-center reports. We aimed to describe the epidemiology and outcomes associated with postoperative tracheostomy in a multi-institutional registry. Methods The Society of Thoracic Surgeons Congenital Heart Database (2000 to 2014) was queried for all index operations with the adverse event “postoperative tracheostomy” or “respiratory failure, requiring tracheostomy.” Patients with preoperative tracheostomy or weighing less than 2.5 kg undergoing isolated closure of patent ductus arteriosus were excluded. Trends in tracheostomy incidence over time from January 2000 to June 2014 were analyzed with a Cochran-Armitage test. The patient characteristics associated with operative mortality were analyzed for January 2010 to June 2014, including deaths occurring up to 6 months after transfer of patients to long-term care facilities. Results From 2000 to 2014, the incidence of tracheostomy after operations for congenital heart disease increased from 0.11% in 2000 to a high of 0.76% in 2012 (p < 0.0001). From 2010 to 2014, 648 patients underwent tracheostomy. The median age at operation was 2.5 months (25th, 75th percentile: 0.4, 7). Prematurity (n = 165, 26%), genetic abnormalities (n = 298, 46%), and preoperative mechanical ventilation (n = 275, 43%) were common. Postoperative adverse events were also common, including cardiac arrest (n = 131, 20%), extracorporeal support (n = 87, 13%), phrenic or laryngeal nerve injury (n = 114, 18%), and neurologic deficit (n = 51, 8%). The operative mortality was 25% (n = 153). Conclusions Tracheostomy as an adverse event of operations for congenital heart disease remains rare but has been increasingly used over the past 15 years. This trend and the considerable mortality risk among patients requiring postoperative tracheostomy support the need for further research in this complex population

Contemporary outcomes of complete atrioventricular septal defect repair: Analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

ObjectiveContemporary outcomes data for complete atrioventricular septal defect (CAVSD) repair are limited. We sought to describe early outcomes of CAVSD repair across a large multicenter cohort, and explore potential associations with patient characteristics, including age, weight, and genetic syndromes.MethodsPatients in the Society of Thoracic Surgeons Congenital Heart Surgery Database having repair of CAVSD (2008-2011) were included. Preoperative, operative, and outcomes data were described. Univariate associations between patient factors and outcomes were described.ResultsOf 2399 patients (101 centers), 78.4% had Down syndrome. Median age at surgery was 4.6 months (interquartile range, 3.5-6.1 months), with 11.8% (n = 284) aged ≤2.5 months. Median weight at surgery was 5.0 kg (interquartile range, 4.3-5.8 kg) with 6.3% (n = 151) < 3.5 kg. Pulmonary artery band removal at CAVSD repair was performed in 122 patients (4.6%). Major complications occurred in 9.8%, including permanent pacemaker implantation in 2.7%. Median postoperative length of stay (PLOS) was 8 days (interquartile range, 5-14 days). Overall hospital mortality was 3.0%. Weight < 3.5 kg and age ≤ 2.5 months were associated with higher mortality, longer PLOS, and increased frequency of major complications. Patients with Down syndrome had lower rates of mortality and morbidities than other patients; PLOS was similar.ConclusionsIn a contemporary multicenter cohort, most patients with CAVSD have repair early in the first year of life. Prior pulmonary artery band is rare. Hospital mortality is generally low, although patients at extremes of low weight and younger age have worse outcomes. Mortality and major complication rates are lower in patients with Down syndrome

Eddy-mediated transport of warm Circumpolar Deep Water across the Antarctic Shelf Break

The Antarctic Slope Front (ASF) modulates ventilation of the abyssal ocean via the export of dense Antarctic Bottom Water (AABW) and constrains shoreward transport of warm Circumpolar Deep Water (CDW) toward marine-terminating glaciers. Along certain stretches of the continental shelf, particularly where AABW is exported, density surfaces connect the shelf waters to the middepth Circumpolar Deep Water offshore, offering a pathway for mesoscale eddies to transport CDW directly onto the continental shelf. Using an eddy-resolving process model of the ASF, the authors show that mesoscale eddies can supply a dynamically significant transport of heat and mass across the continental shelf break. The shoreward transport of surface waters is purely wind driven, while the shoreward CDW transport is entirely due to mesoscale eddy transfer. The CDW flux is sensitive to all aspects of the model's surface forcing and geometry, suggesting that shoreward eddy heat transport may be localized to favorable sections of the continental slope

Risk factors associated with mortality and interventions in 472 neonates with interrupted aortic arch: A Congenital Heart Surgeons Society study

ObjectiveWe sought to determine the prevalence of outcomes and associated patient and management factors for neonates with interrupted aortic arch.MethodsFrom 1987 to 1997, a total of 472 neonates were enrolled prospectively from 33 institutions. Competing risks methodology was used to determine simultaneous risk and associated incremental risk factors for death, initial and subsequent left ventricular outflow tract procedures, and arch reinterventions.ResultsOverall survival was 59% at 16 years after study entry but improved with successive birth cohort. In general, risk factors for death in each of the competing risks analyses included lower birth weight, younger age at study entry, type B interrupted aortic arch, and major associated cardiac anomalies. Of 453 patients who had interrupted aortic arch repair, after 16 years 33% had died and 28% had undergone an arch reintervention. Reintervention was more likely for those who had truncus arteriosus repair, interrupted aortic arch repair by a method other than direct anastomosis with patch augmentation, and the use of polytetrafluoroethylene as either an interposition graft or a patch. From study entry, competing risks after 16 years showed that 28% had died and 34% had undergone an initial left ventricular outflow tract procedure. Initial left ventricular outflow tract procedure was more likely for those with single ventricle, type B interrupted aortic arch, bicuspid aortic valve, or anomalous right subclavian artery. Among those who had undergone an initial left ventricular outflow tract procedure, after 16 years 37% had died and 28% had undergone a second procedure.ConclusionAnatomic features affect mortality and initial left ventricular outflow tract procedures, whereas characteristics of the arch repair affect arch reintervention

Electron spectral function and algebraic spin liquid for the normal state of underdoped high TcT_c superconductors

We propose to describe the spin fluctuations in the normal state of underdoped high $T_{c}$ superconductors as a manifestation of an algebraic spin liquid. We have performed calculations within the slave-boson model to support our proposal. Under the spin-charge separation picture, the normal state (the spin-pseudogap phase) is described by massless Dirac fermions, charged bosons, and a gauge field. We find that the gauge interaction is a marginal perturbation and drives the mean-field free-spinon fixed point to a more complicated spin-quantum-fixed-point -- the algebraic spin liquid, where gapless excitations interact at low energies. The electron spectral function in the normal state was found to have a Luttinger-liquid-like line shape as observed in experiments. The spectral function obtained in the superconducting state shows how a coherent quasiparticle peak appears from the incoherent background as spin and charge recombine.Comment: 4 pages, 3 figures. published versio

Zodiacal Exoplanets In Time (ZEIT) I: A Neptune-sized planet orbiting an M4.5 dwarf in the Hyades Star Cluster

Studying the properties of young planetary systems can shed light on how the dynamics and structure of planets evolve during their most formative years. Recent K2 observations of nearby young clusters (10–800 Myr) have facilitated the discovery of such planetary systems. Here we report the discovery of a Neptune-sized planet transiting an M4.5 dwarf (K2-25) in the Hyades cluster (650–800 Myr). The light curve shows a strong periodic signal at 1.88 days, which we attribute to spot coverage and rotation. We confirm that the planet host is a member of the Hyades by measuring the radial velocity of the system with the high-resolution near-infrared spectrograph Immersion Grating Infrared Spectrometer. This enables us to calculate a distance based on K2-25's kinematics and membership to the Hyades, which in turn provides a stellar radius and mass to ≃ 5%–10%, better than what is currently possible for most Kepler M dwarfs (12%–20%). We use the derived stellar density as a prior on fitting the K2 transit photometry, which provides weak constraints on eccentricity. Utilizing a combination of adaptive optics imaging and high-resolution spectra, we rule out the possibility that the signal is due to a bound or background eclipsing binary, confirming the transits' planetary origin. K2-25b has a radius (3.43}_(-0.31)^(+0.95)R_⊕) much larger than older Kepler planets with similar orbital periods (3.485 days) and host-star masses (0.29 M_⊙). This suggests that close-in planets lose some of their atmospheres past the first few hundred million years. Additional transiting planets around the Hyades, Pleiades, and Praesepe clusters from K2 will help confirm whether this planet is atypical or representative of other close-in planets of similar age

A suite of web applications to streamline the interdisciplinary collaboration in secondary data analyses

BACKGROUND: We describe a system of web applications designed to streamline the interdisciplinary collaboration in outcomes research. DESCRIPTION: The outcomes research process can be described as a set of three interrelated phases: design and selection of data sources, analysis, and output. Each of these phases has inherent challenges that can be addressed by a group of five web applications developed by our group. QuestForm allows for the formulation of relevant and well-structured outcomes research questions; Research Manager facilitates the project management and electronic file exchange among researchers; Analysis Charts facilitate the communication of complex statistical techniques to clinicians with varying previous levels of statistical knowledge; Literature Matrices improve the efficiency of literature reviews. An outcomes research question is used to illustrate the use of the system. CONCLUSIONS: The system presents an alternative to streamline the interdisciplinary collaboration of clinicians, statisticians, programmers, and graduate students