Publications by authors named "Nikolaos Diakos"

Background: Remote hemodynamics-guided management of heart failure (HF) with implantable pulmonary artery pressure sensors has been shown to reduce HF hospitalizations. The widespread clinical adoption of this procedure is constrained by its invasive nature and high cost. We present a noninvasive technology based on a wearable sensor (CardioTag; Cardiosense) and machine learning (ML) for estimating pulmonary capillary wedge pressure (PCWP) in patients with heart failure with reduced ejection fraction (HFrEF).

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Article Synopsis
  • In-hospital mortality rates for patients experiencing cardiogenic shock remain high, even with advanced support devices like VA-ECMO and Impella.
  • A study analyzed blood samples from 11 patients before and after device implantation, focusing on changes in the plasma proteome using SOMAscan technology.
  • The findings indicated that both ECMO and Impella lead to reduced inflammatory markers and increased cell death among inflammatory cells, suggesting that these proteins could be potential targets for new treatments or biomarkers in managing acute myocardial circulatory support (AMCS).
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Immune cell trafficking constitutes a fundamental component of immunological response to tissue injury, but the contribution of intrinsic RNA nucleotide modifications to this response remains elusive. We report that RNA editor ADAR2 exerts a tissue- and stress-specific regulation of endothelial responses to interleukin-6 (IL-6), which tightly controls leukocyte trafficking in IL-6-inflamed and ischemic tissues. Genetic ablation of ADAR2 from vascular endothelial cells diminished myeloid cell rolling and adhesion on vascular walls and reduced immune cell infiltration within ischemic tissues.

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Background Recent prospective multicenter data from patients with advanced heart failure demonstrated that left ventricular assist device (LVAD) support combined with standard heart failure medications, induced significant cardiac structural and functional improvement, leading to high rates of LVAD weaning in selected patients. We investigated whether preintervention myocardial and systemic inflammatory burden could help identify the subset of patients with advanced heart failure prone to LVAD-mediated cardiac improvement to guide patient selection, treatment, and monitoring. Methods and Results Ninety-three patients requiring durable LVAD were prospectively enrolled.

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A 77-year-old man who underwent a heart transplant 7 years ago presented with multiple bloody bowel movements. Endoscopic and histologic evaluation revealed chronic active ileitis, granulomatous inflammation, multinucleated giant cells, and a rare, equivocal acid-fast bacterium in the terminal ileum. Positive sputum cultures for Mycobacterium tuberculosis and acid-fast bacilli established a diagnosis of intestinal tuberculosis, and RIPE (rifabutin, isoniazid, pyrazinamide, ethambutol) therapy was initiated.

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Purpose: We sought to develop and validate machine learning (ML) models to increase the predictive accuracy of mortality after heart transplantation (HT).

Methods And Results: We included adult HT recipients from the United Network for Organ Sharing (UNOS) database between 2010 and 2018 using solely pre-transplant variables. The study cohort comprised 18 625 patients (53 ± 13 years, 73% males) and was randomly split into a derivation and a validation cohort with a 3:1 ratio.

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Left Ventricular Outflow Tract (LVOT) obstruction occurs in approximately 70% of Hypertrophic Cardiomyopathy (HCM) patients and currently requires imaging or invasive testing for diagnosis, sometimes in conjunction with provocative physiological or pharmaceutical stimuli. To identify potential biomarkers of LVOT obstruction, we performed proteomics profiling of 1305 plasma proteins in 12 HCM patients with documented LVOT obstruction, referred for surgical myectomy. Plasma was collected at the surgical preoperative visit, approximately one month prior to surgery and then at the post-surgical visit, approximately 3 months later.

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The metabolic rewiring of cardiomyocytes is a widely accepted hallmark of heart failure (HF). These metabolic changes include a decrease in mitochondrial pyruvate oxidation and an increased export of lactate. We identify the mitochondrial pyruvate carrier (MPC) and the cellular lactate exporter monocarboxylate transporter 4 (MCT4) as pivotal nodes in this metabolic axis.

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In-hospital mortality associated with cardiogenic shock (CS) remains high despite introduction of mechanical circulatory support. In this study, we aimed to investigate whether systemic inflammation is associated with clinical outcomes in CS. We retrospectively analyzed systemic cytokine levels and the neutrophil-to-lymphocyte ratio (NLR), a marker of low-grade inflammation, among 134 patients with CS supported by VA-ECMO or Impella.

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Pressure overload (PO) cardiac hypertrophy and heart failure are associated with generalized insulin resistance and hyperinsulinemia, which may exacerbate left ventricular (LV) remodeling. While PO activates insulin receptor tyrosine kinase activity that is transduced by insulin receptor substrate 1 (IRS1), the present study tested the hypothesis that IRS1 and IRS2 have divergent effects on PO-induced LV remodeling. We therefore subjected mice with cardiomyocyte-restricted deficiency of IRS1 (CIRS1KO) or IRS2 (CIRS2KO) to PO induced by transverse aortic constriction (TAC).

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Background: The coronary vasculature encounters a reduction in pulsatility after implementing durable continuous-flow left ventricular assist device (CF-LVAD) circulatory support. Evidence exists that appropriate pulsatility is required to maintain endothelial cell homeostasis. We hypothesized that coronary artery endothelial function would be impaired after CF-LVAD intervention.

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Ischemic cardiomyopathy (ICM) is the clinical endpoint of coronary heart disease and a leading cause of heart failure. Despite growing demands to develop personalized approaches to treat ICM, progress is limited by inadequate knowledge of its pathogenesis. Since epigenetics has been implicated in the development of other chronic diseases, the current study was designed to determine whether transcriptional and/or epigenetic changes are sufficient to distinguish ICM from other etiologies of heart failure.

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Aims: Adjuvant heart failure (HF) drug therapy in patients undergoing chronic mechanical circulatory support (MCS) is often used in conjunction with a continuous-flow left ventricular assist device (LVAD), but its potential impact is not well defined. The objective of the present study was to examine the effects of conventional HF drug therapy on myocardial structure and function, peripheral organ function and the incidence of adverse events in the setting of MCS.

Methods And Results: Patients with chronic HF requiring LVAD support were prospectively enrolled.

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This study sought to investigate the effects of mechanical unloading on myocardial energetics and the metabolic perturbation of heart failure (HF) in an effort to identify potential new therapeutic targets that could enhance the unloading-induced cardiac recovery. The authors prospectively examined paired human myocardial tissue procured from 31 advanced HF patients at left ventricular assist device (LVAD) implant and at heart transplant plus tissue from 11 normal donors. They identified increased post-LVAD glycolytic metabolites without a coordinate increase in early, tricarboxylic acid (TCA) cycle intermediates.

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Background: Cardiac recovery in response to mechanical unloading by left ventricular assist devices (LVADs) has been demonstrated in subgroups of patients with chronic heart failure (HF). Hallmarks of HF are depletion and disorganization of the transverse tubular system (t-system) in cardiomyocytes. Here, we investigated remodeling of the t-system in human end-stage HF and its role in cardiac recovery.

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Background: Small-scale studies focused mainly on nonischemic cardiomyopathy (NICM) have shown that a subset of left ventricular assist device (LVAD) patients can achieve significant improvement of their native heart function, but the impact of ischemic cardiomyopathy (ICM) has not been specifically investigated. Many patients with acute myocardial infarction are discharged from their index hospitalization without heart failure (HF), only to return much later with overt HF syndrome, mainly caused by chronic remodeling of the noninfarcted region of the myocardium.

Objectives: This study sought to prospectively investigate the effect of ICM HF etiology on LVAD-associated improvement of cardiac structure and function using NICM as control.

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Amiodarone is effective in suppressing arrhythmias in heart failure patients. We investigated the effect of long-term amiodarone administration on myocardial fibrosis and left ventricular (LV) remodeling in a porcine model of ischemic cardiomyopathy. Eighteen infarcted farm pigs were randomized to receive long-term amiodarone administration for 3 months (n = 9) or conventional follow-up (n = 9).

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Background: Although cardiac mitochondrial dysfunction is associated with heart failure (HF), this is a complex syndrome with two predominant etiologies, ischemic HF (iHF) and non-ischemic HF (niHF), and the exact impact of mitochondrial dysfunction in these two distinct forms of HF is unknown.

Methods And Results: To determine the impact of HF etiology on mitochondrial function, respiration was measured in permeabilized cardiac muscle fibers from patients with iHF (n=17), niHF (n=18), and healthy donor hearts (HdH). Oxidative phosphorylation capacity (OXPHOS), assessed as state 3 respiration, fell progressively from HdH to niHF, to iHF (Complex I+II: 54±1; 34±4; 27±3pmol·s(-1)·mg(-1)) as did citrate synthase activity (CSA: 206±18; 129±6; 82±6nmol·mg(-1)·min(-1)).

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Objectives: The aim of this study was to assess the impact of continuous-flow left ventricular assist device (LVAD) type-axial flow (AX) versus centrifugal flow (CR)-on myocardial structural and functional response following mechanical unloading.

Background: The use of continuous-flow LVADs is increasing steadily as a therapeutic option for patients with end-stage heart failure who are not responsive to medical therapy. Whether the type of mechanical unloading influences the myocardial response is yet to be determined.

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