County-level food insecurity is associated with outcomes following cardiac surgery

BACKGROUND

As there is limited literature evaluating food insecurity status (FI) and surgical outcomes, we sought to assess the association between county-level FI and outcomes following cardiac surgery.

METHODS

In a retrospective cohort, patients who underwent coronary artery bypass grafting between 2016 and 2020 were identified utilizing the Medicare Standard Analytic Files. Using County-level FI, patients were stratified into low, moderate, and high cohorts. The primary outcome was textbook outcomes, a measure of "optimal" post-operative outcomes. Adjusted multiple logistic regression and Cox regression models were utilized to evaluate outcomes and survival.

RESULTS

Among 267,914 patients, patients residing in high FI regions were less likely to achieve textbook outcomes (OR: 0.94, 95 ​% CI: 0.90-0.99). When evaluating individual post-operative outcomes of interest, patients residing in high FI regions also had a greater odd of 90-day mortality (OR: 1.24, 95 ​% CI: 1.12-1.36) and extended LOS (OR: 1.07, 95 ​% CI: 1.01-1.14) (all p ​< ​0.0001). Moreover, this population was also at greater risk of 5-year mortality (HR: 1.11, 95 ​% CI: 1.06-1.17) compared with their counterparts from low food insecurity regions. Racial disparities persisted in high FI counties as Black patients had a greater risk of 5-year mortality (HR: 1.27, 95 ​% CI: 1.17-1.38, p ​< ​0.0001) compared with White patients within the same FI level.

CONCLUSIONS

County-level FI was associated with worse outcomes following cardiac surgery.

Alveolar macrophages drive lung fibroblast function in cocultures of IPF and normal patient samples

Idiopathic pulmonary fibrosis (IPF) is characterized by increased collagen accumulation that is progressive and nonresolving. Although fibrosis progression may be regulated by fibroblasts and alveolar macrophage (AM) interactions, this cellular interplay has not been fully elucidated. To study AM-fibroblast interactions, cells were isolated from IPF and normal human lung tissue and cultured independently or together in direct 2-D coculture, direct 3-D coculture, indirect transwell, and in 3-D hydrogels. AM influence on fibroblast function was assessed by gene expression, cytokine/chemokine secretion, and hydrogel contractility. Normal AMs cultured in direct contact with fibroblasts downregulated extracellular matrix (ECM) gene expression whereas IPF AMs had little to no effect. Fibroblast contractility was assessed by encapsulating cocultures in 3-D collagen hydrogels and monitoring gel diameter over time. Both normal and IPF AMs reduced baseline contractility of normal fibroblasts but had little to no effect on IPF fibroblasts. When stimulated with Toll-like receptor (TLR) agonists, IPF AMs increased production of pro-inflammatory cytokines TNFα and IL-1β, compared with normal AMs. TLR ligand stimulation did not alter fibroblast contraction, but stimulation with exogenous TNFα and TGFβ did alter contraction. To determine if the observed changes required cell-to-cell contact, AM-conditioned media and transwell systems were utilized. Transwell culture showed decreased ECM gene expression changes compared with direct coculture and conditioned media from AMs did not alter fibroblast contraction regardless of disease state. Taken together, these data indicate that normal fibroblasts are more responsive to AM crosstalk, and that AM influence on fibroblast behavior depends on cell proximity.

American Society of Transplant Surgeons recommendations on best practices in donation after circulatory death organ procurement

The American Society of Transplant Surgeons supports efforts to increase the number of organs that are critically needed for patients desperately awaiting transplantation. In the United States, transplantation using organs procured from donation after circulatory death (DCD) donors has continued to increase in number. Despite these increases, substantial variability in the utilization and practices of DCD transplantation still exists. To improve DCD organ utilization, it is important to create a set of best practices for DCD recovery. The following recommendations aim to provide guidance on contemporary issues surrounding DCD organ procurement in the United States. A work group was composed of members of the American Society of Transplant Surgeon Scientific Studies Committee and the Thoracic Organ Transplantation Committee. The following topics were identified by the group either as controversial or lacking standardization: prewithdrawal preparation, definition of donor warm ischemia time, DCD surgical technique, combined thoracic and abdominal procurements, and normothermic regional perfusion. The proposed recommendations were classified on the basis of the grade of available evidence and the strength of the recommendation. This information should be valuable for transplant programs as well as for organ procurement organizations and donor hospitals as they develop robust DCD donor procurement protocols.

MG53 attenuates nitrogen mustard-induced acute lung injury

Nitrogen mustard (NM) is an alkylating vesicant that causes severe pulmonary injury. Currently, there are no effective means to counteract vesicant‐induced lung injury. MG53 is a vital component of cell membrane repair and lung protection. Here, we show that mice with ablation of MG53 are more susceptible to NM‐induced lung injury than the wild‐type mice. Treatment of wild‐type mice with exogenous recombinant human MG53 (rhMG53) protein ameliorates NM‐induced lung injury by restoring arterial blood oxygen level, by improving dynamic lung compliance and by reducing airway resistance. Exposure of lung epithelial and endothelial cells to NM leads to intracellular oxidative stress that compromises the intrinsic cell membrane repair function of MG53. Exogenous rhMG53 protein applied to the culture medium protects lung epithelial and endothelial cells from NM‐induced membrane injury and oxidative stress, and enhances survival of the cells. Additionally, we show that loss of MG53 leads to increased vulnerability of macrophages to vesicant‐induced cell death. Overall, these findings support the therapeutic potential of rhMG53 to counteract vesicant‐induced lung injury.

Out-of-hospital cardiac arrest due to refractory pulseless ventricular tachycardia and/or ventricular fibrillation

Background

Survival rates for out-of-hospital cardiac arrest (OOHCA) are extremely low and neurologic recovery is poor. Extracorporeal cardiopulmonary resuscitation (ECPR), which combines extracorporeal membrane oxygenation (ECMO) with cardiopulmonary resuscitation (CPR), has emerged as a viable strategy to improve outcomes in OOHCA. A collaborative ECPR program for out-of-hospital refractory pulseless ventricular tachycardia (VT) and/or ventricular fibrillation (VF) has been developed between The Ohio State University Wexner Medical Center and Columbus Division of Fire Emergency Medical Services (EMS).

Purpose

Outcomes for patients who present as an ECPR alert from the field, but did not meet predefined criteria for placement of extracorporeal membrane oxygenation (ECMO) in the cardiac catheterization laboratory (CCL) is described.

Methods

Between September 15, 2017 and October 12, 2019, 50 subjects presented as an ECPR alert for OOHCA secondary to pulseless VT/VF refractory to defibrillation. All subjects were placed on an automated CPR device prior to transfer to the CCL. From these 50 individuals, 28 (56%) did not meet prespecified laboratory criteria (lactate ≤15 mg/dL, partial pressure of oxygen (PaO2) ≥50 mm Hg, end-tidal carbon dioxide (ETCO2) of ≥10) and did not have a shockable rhythm in the CCL, thus ECMO was not placed and usual care for cardiac arrest was administered.

Results

Nine (32%) of the 28 patients achieved return of spontaneous circulation (ROSC), while the remaining 19 (68%) where pronounced deceased in the CCL. All 9 patients who achieved ROSC underwent a coronary angiography with 4 (44%) requiring percutaneous coronary intervention and 4 (44%) requiring an acute mechanical circulatory support device (Impella with 1 change out to ECMO). Of the patients that achieved ROSC, 4 (44%) were discharged from the hospital with good neurologic recovery; the remaining 5 (56%) ultimately expired during the hospitalization. From the initial 28 patient cohort, there were 4 (14%) patients discharged alive. Patients who achieved ROSC as compared to no ROSC were found on presentation in the CCL to have a significantly lower lactate (12.3±4.3 vs 16.2±3.6, respectively; p=0.03) and greater PaO2 (145±125 vs 47±9, respectively; p=0.01); there was no significant differences between groups in ETCO2, age or emergency services dispatch to CCL arrival time.

Conclusion

This study demonstrates that an ECPR program for OOHCA due to refractory VT/VF may provide benefit to patients that do not meet the predefined criteria for ECMO. This may be due to minimizing no flow/low flow time by early recognition and ongoing CPR en route to the CCL by a skilled EMS team, high efficiency citywide expedited transport/triage, the provision of high quality uninterrupted chest compressions using the mechanical CPR device during transport, and the care provided by highly trained multidisciplinary team members in the CCL.

Funding Acknowledgement

Type of funding sources: None.

Altered microRNA and mRNA profiles during heart failure in the human sinoatrial node

Heart failure (HF) is frequently accompanied with the sinoatrial node (SAN) dysfunction, which causes tachy-brady arrhythmias and increased mortality. MicroRNA (miR) alterations are associated with HF progression. However, the transcriptome of HF human SAN, and its role in HF-associated remodeling of ion channels, transporters, and receptors responsible for SAN automaticity and conduction impairments is unknown. We conducted comprehensive high-throughput transcriptomic analysis of pure human SAN primary pacemaker tissue and neighboring right atrial tissue from human transplanted HF hearts (n = 10) and non-failing (nHF) donor hearts (n = 9), using next-generation sequencing. Overall, 47 miRs and 832 mRNAs related to multiple signaling pathways, including cardiac diseases, tachy-brady arrhythmias and fibrosis, were significantly altered in HF SAN. Of the altered miRs, 27 are predicted to regulate mRNAs of major ion channels and neurotransmitter receptors which are involved in SAN automaticity (e.g. HCN1, HCN4, SLC8A1) and intranodal conduction (e.g. SCN5A, SCN8A) or both (e.g. KCNJ3, KCNJ5). Luciferase reporter assays were used to validate interactions of miRs with predicted mRNA targets. In conclusion, our study provides a profile of altered miRs in HF human SAN, and a novel transcriptome blueprint to identify molecular targets for SAN dysfunction and arrhythmia treatments in HF.

Abstract P421: Analysis Of The Functional Relevance Of Human Beta-myosin Heavy Chain Post-translational Modifications

Sarcomeric proteins have been shown to be a target of post-translational modifications (PTMs). Phosphorylation and acetylation of several sarcomeric proteins have been reported to be important for fine-tuning of myocardial contractility. Given the emerging importance of understanding the potential role of PTMs on cardiac muscle performance in healthy and diseased states, we sought to identify novel PTMs on human cardiac beta-myosin heavy chain (beta-MHC). We found several high confidence beta-MHC peptides modified by K-acetylation and S- and T-phosphorylation found in non-diseased, ischemic, and non-ischemic human heart samples. Using bottom-up proteomics and label-free quantification, we identified seven high-confidence peptides (K34, K58, S210, T215, K429, K951, K1195) with K951 displaying significant reduction in acetylation levels in both ischemic and non-ischemic failing hearts compared to donor hearts. Molecular dynamics simulations were performed to better understand the functional significance of the beta-MHC PTMs. Focus was placed on modifications in the regions with greatest potential functional significance as well as modified residues with significantly altered abundance in diseased states (K951-Ac at the myosin tail nearby a binding site for myosin heads in the super-relaxed state). K951 is located in the myosin tail (S2) at the C-terminal end of simulated structure. In both unmodified and modified simulations, the tail fragment showed significant flexibility and partial unfolding at the C-terminus. In the unmodified simulations, the inter- and intra-helical contacts were maintained. However, when beta-MHC is acetylated at residue 951, these helical contacts were altered as the uncharged acetylated residue no longer formed strong hydrogen bonds with a residue of the opposite chain. This facilitated changes increase in inter-helical contacts, an increase in inter-helical distance, and disruption of the coiled-coil tail domain structure. Our study suggests that there are distinct differences in beta-MHC acetylation levels that appear to be influenced more by location of the modified residues than the type of heart disease (ischemic- and non-ischemic heart failure). Additionally, we speculate that these PTMs have the potential to modulate the interactions between beta-MHC and other regulatory sarcomeric proteins, as well as ADP-release rate of myosin, flexibility of S2 fragment, and cardiac myofilament contractility under normal and heart failure condition.

Abstract MP259: The Role Of Sertad4 In Pathological Cardiac Remodeling

Over 6 million Americans suffer from heart failure (HF) while the 5-year mortality rate following first admission for HF is over 40%. Cardiac fibrosis is a clinical hallmark of HF, regardless of the initiating pathology and is thought to contribute to disease progression. Using an epigenomics discovery approach, we uncovered a nuclear protein, Sertad4, as a potential anti-fibrotic target. Our data indicate that Sertad4 is a positive regulator of fibroblast activation. Specifically, cultured cardiac fibroblast experiments demonstrate that Sertad4 targeting with shRNAs blocks fibroblast proliferation and causes cells to arrest in the G2/M phase of the cell cycle. Also, shRNA targeting of Sertad4 dramatically blocked activation of myofibroblast differentiation genes (αSMA/POSTN/COL1A1). Mechanistically, these effects appear to be mediated by Sertad4 regulation of SMAD2 protein stability in the presence of TGF-β1 stimulation as demonstrated by proteasome inhibition experiments. RNA-seq analysis indicate that Sertad4 also regulates the expression of genes involved in ubiquitination and proteasome degradation. Next, we sought to determine the effect of global Sertad4 knockout on post-myocardial infarct (MI) remodeling and cardiac function in mice. After 4 weeks of permanent LAD ligation, echocardiography was performed to measure systolic function. Relative to wild-type (WT) controls, the Sertad4 KO mice showed preserved systolic function as evident by improved ejection fraction (WT 14.4 +/- 3.6 vs. KO 33.9+/-5.9, p=0.035) and fractional shortening (WT 6.5 +/- 1.7 vs. KO 16.4 +/- 3.4, p=0.046). β-gal staining in the Sertad4/LacZ reporter mouse subjected to MI showed robust Sertad4/LacZ expression in the ischemic scar and boarder-zone with almost no expression in control hearts. This data supports the notion that Sertad4 has a key role in cardiac remodeling in response to ischemic injury.

STratification risk analysis in OPerative management (STOP score) for drug-induced endocarditis

BACKGROUND

The opioid epidemic has seen a drastic increase in the incidence of drug-associated infective endocarditis (IE). No clinical tool exists to predict operative morbidity and mortality in patients undergoing surgery.

METHODS

A multi-institutional database was reviewed between 2011 and 2018. Multivariate logistic regression was fitted in an automated stepwise fashion. The STratification risk analysis in OPerative management of drug-associated IE (STOP) score was constructed. Morbidity was defined as reintubation, prolonged ventilation, pneumonia, renal failure, dialysis, stroke, reoperation for bleeding, and a permanent pacemaker. Cross-validation provided an unbiased estimate of out-of-sample performance.

RESULTS

A total of 1181 patients underwent surgery for drug-associated IE (median age, 39; interquartile range [IQR], 30-54, 386 women [32.7%], 341 reoperations for prosthetic valve endocarditis [28.9%], 316 patients with multivalve disease [26.8%]). Operative morbidity and mortality were 41.1% and 5.9%, respectively. Predictors of morbidity were dialysis (95% confidence interval [CI], 1.16-2.82), emergent intervention (1.83-4.73), multivalve procedure (1.01-1.98), causative organisms other than Streptococcus (1.09-2.02), and type of valve procedure performed [aortic valve procedure (1.07-2.15), mitral valve replacement (1.03-2.05), tricuspid valve replacement (1.21-2.60)]. Predictors of mortality were dialysis (1.29-5.74), active endocarditis (1.32-83), lung disease (1.25-5.43), emergent intervention (1.69-6.60), prosthetic valve endocarditis (1.24-3.69), aortic valve procedure (1.49-5.92) and multivalve disease (1.00-2.95). Variables maximizing explanatory power were translated into a scoring system. Each point increased odds of morbidity and mortality by 22.0% and 22.4% with an accuracy of 94.0% and 94.1%, respectively.

CONCLUSION

Drug-related IE is associated with significant morbidity and mortality. An easily-applied risk stratification score may aid in clinical decision-making.

Modeling risk of coronary obstruction during transcatheter aortic valve replacement

OBJECTIVE

In this study we aimed to evaluate risk of coronary obstruction during transcatheter aortic valve replacement and develop improved criteria based on computational modeling.

METHODS

Patient specific 3-dimensional models were constructed and validated for 28 patients out of 600 patients who were flagged as high risk for coronary obstruction (defined as meeting coronary ostium height < 14 mm and/or sinus of Valsalva diameter [SOVd] < 30 mm). The models consisted finite element analysis to predict the post- transcatheter aortic valve replacement native cusp apposition relative to the coronary ostium and were validated in vitro. The distance from cusp to coronary ostium (DLC) was derived from the 3-dimensional models and indexed with the coronary artery diameter to yield a fractional obstruction measure (DLC/d).

RESULTS

Twenty-two out of 28 high-risk patients successfully underwent transcatheter aortic valve replacement without coronary obstruction and 6 did not. DLC/d between the 2 groups was significantly different (P < .00078), whereas neither coronary ostium height nor SOVd were significantly different (P > .32). A cutoff of DLC/d < 0.7 was predictive with 100% sensitivity and 95.7% specificity. The optimal sensitivity and specificity of coronary ostium height and SOVd in this high-risk group was only 60% and 40%, respectively, for cutoff coronary ostium height of 10 mm and SOVd of 30.5 mm.

CONCLUSIONS

Three-dimensional modeling has the potential to enable more patients to be safely treated with transcatheter aortic valve replacement who have a low-lying coronary ostium or small SOVd. DLC/d is more predictive of obstruction than coronary ostium height and SOVd.

Impact of anticoagulation strategy and agents on extracorporeal membrane oxygenation therapy

Introduction:

Extracorporeal membrane oxygenation mandates balancing the risk of thromboembolic complications with bleeding. We aimed to evaluate pragmatic anticoagulation regimens during extracorporeal membrane oxygenation and compare thromboembolic and bleeding outcomes.

Methods:

This retrospective, single-center study reviewed patients on venovenous or venoarterial extracorporeal membrane oxygenation for a minimum of 24 hours over a 5-year period. The primary outcome was composite thromboembolic events per day of extracorporeal membrane oxygenation. Secondary outcomes included composite bleeding complications, percent of measured activated partial thromboplastin times in goal range, and comparing events with therapeutic anticoagulation for the majority of the extracorporeal membrane oxygenation run (>50% of time on extracorporeal membrane oxygenation) versus non-therapeutic anticoagulation (therapeutic anticoagulation <50% of time).

Results:

For the primary analysis, 100 patients received heparin, 10 received bivalirudin, and 43 were transitioned between heparin and bivalirudin. No significant differences were identified comparing the heparin group to the bivalirudin (RR = 0.427, p = 0.156) or transitioned group (RR = 1.274, p = 0.325). There were no differences in the rate of bleeding events when comparing the heparin group to the bivalirudin (RR = 0.626, p = 0.250) or transitioned group (RR = 0.742, p = 0.116). An increased number of adjustments to the anticoagulants was associated with a statistically higher rate of bleeding events per day (p = 0.006).

Conclusion:

There were no differences in thromboembolic or bleeding events when comparing different anticoagulant regimens. Adjustments to the anticoagulants are more likely to occur when bleeding is observed. Due to variability in anticoagulation, there is a need to standardize anticoagulation with extracorporeal membrane oxygenation.