Outcomes of Extracorporeal Cardiopulmonary Resuscitation for In-Hospital Cardiac Arrest Among Children With Noncardiac Illness Categories.

OBJECTIVES: The objective of this study was to determine the association of the use of extracorporeal cardiopulmonary resuscitation (ECPR) with survival to hospital discharge in pediatric patients with a noncardiac illness category. A secondary objective was to report on trends in ECPR usage in this population for 20 years. DESIGN: Retrospective multicenter cohort study. SETTING: Hospitals contributing data to the American Heart Association's Get With The Guidelines-Resuscitation registry between 2000 and 2021. PATIENTS: Children (<18 yr) with noncardiac illness category who received greater than or equal to 30 minutes of cardiopulmonary resuscitation (CPR) for in-hospital cardiac arrest. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Propensity score weighting balanced ECPR and conventional CPR (CCPR) groups on hospital and patient characteristics. Multivariable logistic regression incorporating these scores tested the association of ECPR with survival to discharge. A Bayesian logistic regression model estimated the probability of a positive effect from ECPR. A secondary analysis explored temporal trends in ECPR utilization. Of 875 patients, 159 received ECPR and 716 received CCPR. The median age was 1.0 [interquartile range: 0.2-7.0] year. Most patients (597/875; 68%) had a primary diagnosis of respiratory insufficiency. Median CPR duration was 45 [35-63] minutes. ECPR use increased over time ( p < 0.001). We did not identify differences in survival to discharge between the ECPR group (21.4%) and the CCPR group (16.2%) in univariable analysis ( p = 0.13) or propensity-weighted multivariable logistic regression (adjusted odds ratio 1.42 [95% CI, 0.84-2.40; p = 0.19]). The Bayesian model estimated an 85.1% posterior probability of a positive effect of ECPR on survival to discharge. CONCLUSIONS: ECPR usage increased substantially for the last 20 years. We failed to identify a significant association between ECPR and survival to hospital discharge, although a post hoc Bayesian analysis suggested a survival benefit (85% posterior probability).

Assessment of echocardiographic interpretation of dual-lumen cannula during venovenous extracorporeal membrane oxygenation use for pediatric respiratory failure.

PURPOSE: Echocardiography is considered essential during cannulation placement and manipulations. Literature evaluating transthoracic echocardiography (TTE) usage during pediatric VV-ECMO is scant. The purpose of this study is to describe the use of echocardiography during VV-ECMO at a large, quaternary children's hospital. METHODS: A retrospective, single-year cohort study was performed of pediatric patients on VV-ECMO via dual-lumen cannula at our institution from January 2019 through December 2019. For each echocardiogram, final cannula component (re-infusion port (ReP), distal tip, proximal port and distal port) positions were evaluated by one echocardiographer. For TTEs with ReP in the right atrium, two echocardiographers independently evaluated ReP direction using 2-point (Yes/No) and 4-point scales, which were semi-quantitative protocols using color Doppler images to estimate ReP jet direction to the tricuspid valve. Cohen's kappa or weighted kappa was used to measure interrater agreement. RESULTS: During study period, 11 patients (64% male) received VV-ECMO with 49 TTEs and one transesophageal echocardiogram performed. The median patient age was 4.3 years [IQR: 1.1-11.5] and median VV-ECMO run time of 192 h [90-349]. The median time between TTEs on VV-ECMO was 34 h [8.3-65]. Most common position for the ReP was the right atrium (n = 33, 67%), and ReP location was not identified in five TTEs (10%). For ReP flow direction, echocardiographers agreed on 82% of TTEs using 2-point evaluation. There was only moderate agreement between echocardiographers on the 2-point and 4-point assessments (k = .54, kw = .46 respectively). CONCLUSIONS: TTE is the predominant cardiac ultrasound modality used during VV-ECMO for pediatric respiratory failure. Subjective evaluation of VV-ECMO ReP jet direction in the right atrium is challenging, regardless of assessment method.

GRK5 is a regulator of fibroblast activation and cardiac fibrosis.

Pathological remodeling of the heart is a hallmark of chronic heart failure (HF) and these structural changes further perpetuate the disease. Cardiac fibroblasts are the critical cell type that is responsible for maintaining the structural integrity of the heart. Stress conditions, such as a myocardial infarction (MI), can activate quiescent fibroblasts into synthetic and contractile myofibroblasts. G protein-coupled receptor kinase 5 (GRK5) is an important mediator of cardiovascular homeostasis through dampening of GPCR signaling, and is expressed in the heart and up-regulated in human HF. Of note, GRK5 has been demonstrated to translocate to the nucleus in cardiomyocytes in a calcium-calmodulin (Ca2+-CAM)-dependent manner, promoting hypertrophic gene transcription through activation of nuclear factor of activated T cells (NFAT). Interestingly, NFAT is also involved in fibroblast activation. GRK5 is highly expressed and active in cardiac fibroblasts; however, its pathophysiological role in these crucial cardiac cells is unknown. We demonstrate using adult cardiac fibroblasts that genetic deletion of GRK5 inhibits angiotensin II (AngII)-mediated fibroblast activation. Fibroblast-specific deletion of GRK5 in mice led to decreased fibrosis and cardiac hypertrophy after chronic AngII infusion or after ischemic injury compared to nontransgenic littermate controls (NLCs). Mechanistically, we show that nuclear translocation of GRK5 is involved in fibroblast activation. These data demonstrate that GRK5 is a regulator of fibroblast activation in vitro and cardiac fibrosis in vivo. This adds to previously published data which demonstrate the potential beneficial effects of GRK5 inhibition in the context of cardiac disease.

Acute Compartment Syndrome in Pediatric Patients on Extracorporeal Membrane Oxygenation Support.

BACKGROUND: When acute compartment syndrome (ACS) occurs in pediatric patients requiring venoarterial extracorporeal membrane oxygen (VA ECMO) support, there is little data to guide surgeons on appropriate management. The purpose of this study is to characterize the presentation, diagnosis, timeline, and outcomes of patients who developed this complication. METHODS: This is a single-center retrospective case series of children below 19 years old on VA ECMO support who subsequently developed extremity ACS between January 2016 and December 2022. Outcomes included fasciotomy findings, amputation, mortality, and documented function at the last follow-up. RESULTS: Of 343 patients on VA ECMO support, 18 (5.2%) were diagnosed with ACS a median 29 hours after starting ECMO. Initial cannulation sites included 8 femoral, 6 neck, and 4 central. Femoral artery cannulation was associated with an increased risk of ACS [odds ratio=6.0 (CI: 2.2 to 15), P <0.0001]. In the hospital, the mortality rate was 56% (10/18). Fourteen (78%) patients received fasciotomies a median of 1.2 hours after ACS diagnosis. Only 4 (29%) patients had all healthy muscles at initial fasciotomy, while 9 (64%) had poor muscular findings in at least 1 compartment. Patients with worse findings at fasciotomy had a significantly longer duration between ischemia onset and ACS diagnosis. Patients required a median of 1.5 additional procedures after fasciotomy, and only 1 (7%) developed a surgical site infection. Of the 7 surviving fasciotomy patients, 2 required amputations, 3 developed an equinus contracture, 1 developed foot drop, and 3 had no ACS-related deficits. Four patients did not receive fasciotomies: 3 were deemed too ill and later died, and 1 was diagnosed too late to benefit. The only surviving nonfasciotomy patient required bilateral amputations. CONCLUSIONS: Pediatric ECMO-associated ACS is not exclusive to patients with femoral artery cannulation. The majority of fasciotomy patients were diagnosed with ACS after muscle necrosis had already started. We were unable to definitively conclude whether fasciotomies provide better outcomes. There is a need for increased awareness and earlier recognition of this rare yet potentially devastating complication. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Risk Stratification by Percent Liver Herniation in Congenital Diaphragmatic Hernia.

INTRODUCTION: Congenital diaphragmatic hernia is associated with pulmonary hypoplasia, pulmonary hypertension, and significant neonatal morbidity. Although intrathoracic liver herniation (LH) >20% is associated with adverse outcomes, the relationship between LH <20% and outcomes is poorly characterized. METHODS: A single-center retrospective cohort study was performed from 2011 to 2020 of 80 fetuses with left-sided congenital diaphragmatic hernia that were delivered and repaired at our institution. Perinatal, perioperative, and postoperative data were collected. We evaluated the association of %LH with outcomes as a stratified ordinal variable (0%-10% LH, 10%-19% LH, and >20% LH) and as a continuous variable. Data were analyzed by analysis of variance with Bonferroni post hoc analysis, chi-square analyses, and univariate logistic regression. RESULTS: Extracorporeal membrane oxygenation (ECMO) (P < 0.001), repair on ECMO (P = 0.002), repair with patch (P < 0.001), length of stay (P = 0.002), inhaled nitric oxide use (P < 0.001), and sildenafil use at discharge (P < 0.001), showed significant differences among LH groups. There were no differences among the groups concerning survival (at discharge, 6 mo, and 1 y) and tracheostomy. On further analysis there was no difference between 10% and 19% LH and ≥20% LH patients concerning ECMO (P = 0.55), repair on ECMO (P = 0.54), repair with patch (P = 1.00), length of stay (P = 1.00), and inhaled nitric oxide use (P = 0.33). Logistic regression analysis displayed a significant association with LH and ECMO, repair on ECMO, repair with patch, inhaled nitric oxide use, and sildenafil use. CONCLUSIONS: Our analysis displays no significant difference in perinatal management between patients with 10%-19% and ≥20% LH. These findings suggest that the historical cutoff of ≥20% LH may not be sufficient alone to guide perinatal counseling and decision-making.

Characterization of Suboptimal Responses to Fetoscopic Endoluminal Tracheal Occlusion in Congenital Diaphragmatic Hernia.

INTRODUCTION: The aim of the study was to characterize the changes in fetal lung volume following fetoscopic endoluminal tracheal occlusion (FETO) that are associated with infant survival and need for extracorporeal membrane oxygenation (ECMO) in congenital diaphragmatic hernia (CDH). METHODS: Fetuses with CDH who underwent FETO at a single institution were included. CDH cases were reclassified by MRI metrics [observed-to-expected total lung volume (O/E TLV) and percent liver herniation]. The percent changes of MRI metrics after FETO were calculated. ROC-derived cutoffs of these changes were derived to predict infant survival to discharge. Regression analyses were done to determine the association between these cutoffs with infant survival and ECMO need, adjusted for site of CDH, gestational age at delivery, fetal sex, and CDH severity. RESULTS: Thirty CDH cases were included. ROC analysis demonstrated that post-FETO increases in O/E TLV had an area under the curve of 0.74 (p = 0.035) for the prediction of survival to hospital discharge; a cutoff of less than 10% was selected. Fetuses with a <10% post-FETO increase in O/E TLV had lower survival to hospital discharge [44.8% vs. 91.7%; p = 0.018] and higher ECMO use [61.1% vs. 16.7%; p = 0.026] compared to those with an O/E TLV increase ≥10%. Similar results were observed when the analyses were restricted to left-sided CDH cases. A post-FETO <10% increase in O/E TLV was independently associated with lower survival at hospital discharge (aOR: 0.073, 95% CI: 0.008-0.689; p = 0.022) and at 12 months of age (aOR: 0.091, 95% CI: 0.01-0.825; p = 0.036) as well as with higher ECMO use (aOR: 7.88, 95% CI: 1.31-47.04; p = 0.024). CONCLUSION: Fetuses with less than 10% increase in O/E TLV following the FETO procedure are at increased risk for requiring ECMO and for death in the postnatal period when adjusted for gestational age at delivery, CDH severity, and other confounders.

Perturbation of the interactions of calmodulin with GRK5 using a natural product chemical probe.

G protein-coupled receptor (GPCR) kinases (GRKs) are responsible for initiating desensitization of activated GPCRs. GRK5 is potently inhibited by the calcium-sensing protein calmodulin (CaM), which leads to nuclear translocation of GRK5 and promotion of cardiac hypertrophy. Herein, we report the architecture of the Ca2+·CaM-GRK5 complex determined by small-angle X-ray scattering and negative-stain electron microscopy. Ca2+·CaM binds primarily to the small lobe of the kinase domain of GRK5 near elements critical for receptor interaction and membrane association, thereby inhibiting receptor phosphorylation while activating the kinase for phosphorylation of soluble substrates. To define the role of each lobe of Ca2+·CaM, we utilized the natural product malbrancheamide as a chemical probe to show that the C-terminal lobe of Ca2+·CaM regulates membrane binding while the N-terminal lobe regulates receptor phosphorylation and kinase domain activation. In cells, malbrancheamide attenuated GRK5 nuclear translocation and effectively blocked the hypertrophic response, demonstrating the utility of this natural product and its derivatives in probing Ca2+·CaM-dependent hypertrophy.

Genomic Binding Patterns of Forkhead Box Protein O1 Reveal Its Unique Role in Cardiac Hypertrophy.

BACKGROUND: Cardiac hypertrophic growth is mediated by robust changes in gene expression and changes that underlie the increase in cardiomyocyte size. The former is regulated by RNA polymerase II (pol II) de novo recruitment or loss; the latter involves incremental increases in the transcriptional elongation activity of pol II that is preassembled at the transcription start site. The differential regulation of these distinct processes by transcription factors remains unknown. Forkhead box protein O1 (FoxO1) is an insulin-sensitive transcription factor that is also regulated by hypertrophic stimuli in the heart. However, the scope of its gene regulation remains unexplored. METHODS: To address this, we performed FoxO1 chromatin immunoprecipitation-deep sequencing in mouse hearts after 7 days of isoproterenol injections (3 mg·kg-1·mg-1), transverse aortic constriction, or vehicle injection/sham surgery. RESULTS: Our data demonstrate increases in FoxO1 chromatin binding during cardiac hypertrophic growth, which positively correlate with extent of hypertrophy. To assess the role of FoxO1 on pol II dynamics and gene expression, the FoxO1 chromatin immunoprecipitation-deep sequencing results were aligned with those of pol II chromatin immunoprecipitation-deep sequencing across the chromosomal coordinates of sham- or transverse aortic constriction-operated mouse hearts. This uncovered that FoxO1 binds to the promoters of 60% of cardiac-expressed genes at baseline and 91% after transverse aortic constriction. FoxO1 binding is increased in genes regulated by pol II de novo recruitment, loss, or pause-release. In vitro, endothelin-1- and, in vivo, pressure overload-induced cardiomyocyte hypertrophic growth is prevented with FoxO1 knockdown or deletion, which was accompanied by reductions in inducible genes, including Comtd1 in vitro and Fstl1 and Uck2 in vivo. CONCLUSIONS: Together, our data suggest that FoxO1 may mediate cardiac hypertrophic growth via regulation of pol II de novo recruitment and pause-release; the latter represents the majority (59%) of FoxO1-bound, pol II-regulated genes after pressure overload. These findings demonstrate the breadth of transcriptional regulation by FoxO1 during cardiac hypertrophy, information that is essential for its therapeutic targeting.

Safely repositioning dual-lumen ECMO cannulas with a transfemoral lasso snare.

INTRODUCTION: Dual-lumen cannulas were designed to provide venovenous extracorporeal membrane oxygenation (VV ECMO) with single-vessel access. Anatomic and size considerations may make appropriate placement challenging in children. Dual-lumen cannulas are repositioned in 20-69% of pediatric patients, which can be difficult without transient discontinuation of ECMO support. METHODS: We repositioned three dual-lumen ECMO cannulas introduced via the right internal jugular vein using a transfemoral snare technique under real-time ultrasound and fluoroscopy. RESULTS: Two of three patients were supported on VV ECMO and one on veno-veno-arterial (VV-A) ECMO. Two of the three patients had their dual-lumen cannula repositioned under ultrasound and fluoroscopy guidance and one was repositioned just with ultrasound. No patient experienced a complication from the transfemoral snare technique such as femoral hematoma, hemorrhage or limb ischemia. CONCLUSION: We describe three patients who successfully had dual-lumen cannulas repositioned without cessation of ECMO using a transfemoral "lasso" technique.

Outcomes of pediatric patients with oncologic disease or following hematopoietic stem cell transplant supported on extracorporeal membrane oxygenation: The PEDECOR experience.

BACKGROUND: Outcomes for patients with oncologic disease and/or after hematopoietic stem cell transplant (HSCT) requiring intensive care unit admission have improved, but indications for and outcomes after extracorporeal membrane oxygenation (ECMO) support in this population are poorly characterized. PROCEDURE: We analyzed data from consecutive patients < 18 years with oncologic disease and/or after HSCT reported to a pediatric ECMO registry by nine pediatric centers in the United States between 2011 and 2018. RESULTS: We identified 18 ECMO patients with oncologic disease and/or HSCT, and 415 ECMO controls matched with a propensity score algorithm based on age, gender, race, severity of illness at admission, and reason for ECMO. The primary indication for ECMO was respiratory failure in 66.7% in the oncologic disease and/or HSCT group, and in 70.7% in the matched ECMO control group. Eleven of 18 patients survived to hospital discharge (61.1%), similar to the matched control group (60.8%), P = 0.979. Children with oncologic disease and/or HSCT had lower mean platelet counts during ECMO and received higher volumes of platelets compared with the control group, mean 14.6 mL/kg/day (standard deviations [SD], 9.8) versus mean 9.3 mL/kg/day (SD, 10.4), P = 0.001. Of the 11 surviving children with oncologic disease and/or HSCT, five sustained new neurologic disorders (45.5%) versus 45 of 222 (20.3%) in the control group, P = 0.061. Bleeding complications were similar in the two groups. CONCLUSIONS: Outcomes of patients with oncologic disease and/or HSCT supported on ECMO in the current era are not significantly different compared with matched ECMO controls and are improved from previously published reports.

The expanding GRK interactome: Implications in cardiovascular disease and potential for therapeutic development.

Heart failure (HF) is a global epidemic with the highest degree of mortality and morbidity of any disease presently studied. G protein-coupled receptors (GPCRs) are prominent regulators of cardiovascular function. Activated GPCRs are "turned off" by GPCR kinases (GRKs) in a process known as "desensitization". GRKs 2 and 5 are highly expressed in the heart, and known to be upregulated in HF. Over the last 20 years, both GRK2 and GRK5 have been demonstrated to be critical mediators of the molecular alterations that occur in the failing heart. In the present review, we will highlight recent findings that further characterize "non-canonical" GRK signaling observed in HF. Further, we will also present potential therapeutic strategies (i.e. small molecule inhibition, microRNAs, gene therapy) that may have potential in combating the deleterious effects of GRKs in HF.

ß-adrenergic receptor-mediated cardiac contractility is inhibited via vasopressin type 1A-receptor-dependent signaling.

BACKGROUND: Enhanced arginine vasopressin levels are associated with increased mortality during end-stage human heart failure, and cardiac arginine vasopressin type 1A receptor (V1AR) expression becomes increased. Additionally, mice with cardiac-restricted V1AR overexpression develop cardiomyopathy and decreased ß-adrenergic receptor (ßAR) responsiveness. This led us to hypothesize that V1AR signaling regulates ßAR responsiveness and in doing so contributes to development of heart failure. METHODS AND RESULTS: Transaortic constriction resulted in decreased cardiac function and ßAR density and increased cardiac V1AR expression, effects reversed by a V1AR-selective antagonist. Molecularly, V1AR stimulation led to decreased ßAR ligand affinity, as well as ßAR-induced Ca(2+) mobilization and cAMP generation in isolated adult cardiomyocytes, effects recapitulated via ex vivo Langendorff analysis. V1AR-mediated regulation of ßAR responsiveness was demonstrated to occur in a previously unrecognized Gq protein-independent/G protein receptor kinase-dependent manner. CONCLUSIONS: This newly discovered relationship between cardiac V1AR and ßAR may be informative for the treatment of patients with acute decompensated heart failure and elevated arginine vasopressin.

Decreased levels of BAG3 in a family with a rare variant and in idiopathic dilated cardiomyopathy.

The most common cause of dilated cardiomyopathy and heart failure (HF) is ischemic heart disease; however, in a third of all patients the cause remains undefined and patients are diagnosed as having idiopathic dilated cardiomyopathy (IDC). Recent studies suggest that many patients with IDC have a family history of HF and rare genetic variants in over 35 genes have been shown to be causative of disease. We employed whole-exome sequencing to identify the causative variant in a large family with autosomal dominant transmission of dilated cardiomyopathy. Sequencing and subsequent informatics revealed a novel 10-nucleotide deletion in the BCL2-associated athanogene 3 (BAG3) gene (Ch10:del 121436332_12143641: del. 1266_1275 [NM 004281]) that segregated with all affected individuals. The deletion predicted a shift in the reading frame with the resultant deletion of 135 amino acids from the C-terminal end of the protein. Consistent with genetic variants in genes encoding other sarcomeric proteins there was a considerable amount of genetic heterogeneity in the affected family members. Interestingly, we also found that the levels of BAG3 protein were significantly reduced in the hearts from unrelated patients with end-stage HF undergoing cardiac transplantation when compared with non-failing controls. Diminished levels of BAG3 protein may be associated with both familial and non-familial forms of dilated cardiomyopathy.

SAMPL4 & DOCK3.7: lessons for automated docking procedures.

The SAMPL4 challenges were used to test current automated methods for solvation energy, virtual screening, pose and affinity prediction of the molecular docking pipeline DOCK 3.7. Additionally, first-order models of binding affinity were proposed as milestones for any method predicting binding affinity. Several important discoveries about the molecular docking software were made during the challenge: (1) Solvation energies of ligands were five-fold worse than any other method used in SAMPL4, including methods that were similarly fast, (2) HIV Integrase is a challenging target, but automated docking on the correct allosteric site performed well in terms of virtual screening and pose prediction (compared to other methods) but affinity prediction, as expected, was very poor, (3) Molecular docking grid sizes can be very important, serious errors were discovered with default settings that have been adjusted for all future work. Overall, lessons from SAMPL4 suggest many changes to molecular docking tools, not just DOCK 3.7, that could improve the state of the art. Future difficulties and projects will be discussed.