bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-homogeneous cross section variation enhanced flexoelectric coupling in semiconductor beams and its application in charge carrier redistribution
Authors: Zhao Luke , Li Peng , Jin Feng
Published: February 2022

A pure bending semiconductor beam that exhibits a non-homogeneous cross section variation enhanced flexoelectric coupling effect is investigated in this paper from the point of view of theoretical analysis and numerical calculations. According to the macroscopic theory of flexoelectric semiconductors, a one-dimensional bending model for a simple-supported beam with variable cross section is developed. The semi-analytical method, which is composed of cosine series and supplementary functions, is introduced to solve the partial differential equations with variable coefficients. Before the analysis, the convergence and correctness of the semi-analytical method are demonstrated systematically. The calculated results show that both the electric potential and the charge carrier distribute non-homogeneously in the entire beam under a pair of symmetric bending moments. It is revealed that more carriers, a larger electric potential, and more charges tend to concentrate in the zone near the ends. After introducing a dimensionless carrier density, this paper systematically investigates the non-homogeneous cross section variation effect on the flexoelectric coupling for charge carrier redistribution. It is indicated that more perturbation carriers in a non-uniform beam are produced by the enhanced flexoelectric coupling. The demonstration of this concept could be potential guidance for designing new semiconductor devices.
Attention-enhanced neural network models for turbulence simulation
Authors: Peng Wenhui , Yuan Zelong , Wang Jianchun
Published: February 2022

Deep neural network models have shown great potential in accelerating the simulation of fluid dynamic systems. Once trained, these models can make inferences within seconds, thus can be extremely efficient. However, it becomes more difficult for neural networks to make accurate predictions when the flow becomes more chaotic and turbulent at higher Reynolds numbers. One of the most important reasons is that existing models lack the mechanism to handle the unique characteristic of high-Reynolds-number turbulent flow; multi-scale flow structures are nonuniformly distributed and strongly nonequilibrium. In this work, we address this issue with the concept of visual attention: intuitively, we expect the attention module to capture the nonequilibrium of turbulence by automatically adjusting weights on different regions. We compare the model performance against a state-of-the-art neural network model as the baseline, the Fourier neural operator, on a two-dimensional turbulence prediction task. Numerical experiments show that the attention-enhanced neural network model outperforms existing state-of-the-art baselines, and can accurately reconstruct a variety of statistics and instantaneous spatial structures of turbulence at high Reynolds numbers. Furthermore, the attention mechanism provides 40% error reduction with 1% increase in parameters, at the same level of computational cost.
Computational analysis of transient XMCD sum rules for laser pumped systems: When do they fail?
Authors: Sharma S. , Shallcross S. , Elliott P. , Eisebitt S. , Schmising C. von Korff , Dewhurst J. K.
Published: February 2022

In highly non-equilibrium conditions of laser induced spin dynamics, magnetic moments can only be obtained from the spectral information, most commonly from spectroscopy of core or semi-core states using the so-called x-ray magnetic circular dichroism (XMCD) sum rules. The validity of these sum rules in tracking femtosecond spin dynamics remains, however, an open question. Employing the time dependent extension of the density functional theory (TD-DFT), we compare spectroscopically obtained spin moments with those directly calculated from TD-DFT densities. We find that for pump pulses with low fluence, these two very distinct routes to the spin moment are, for Co and Ni, in excellent agreement, validating the experimental approach. However, for short and/or intense pulses with high fluence, the XMCD sum rules fail with errors exceeding 50%. This failure is most pronounced during the pulse and occurs when the pump pulse excites charges out of the d-band and into sp-character bands, invalidating the core or semi-core to d-state transitions assumed by the XMCD sum rules.
Modulation of slippage at brine–oil interfaces by surfactants: The effects of surfactant density and tail length
Authors: Ham Seokgyun , Narayanan Nair Arun K. , Sun Shuyu , Qiao Rui
Published: February 2022

Fluid transport involving brine–oil interfaces plays an important role in applications including enhanced oil recovery and oil–brine separation and can be affected markedly by the slippage at these interfaces. The slippage at brine–oil interfaces, however, is not well understood, especially in the presence of surfactants, which are ubiquitous in natural and engineering systems. Here, we report molecular dynamics studies of the slippage at brine–decane interfaces in the presence of two surfactants, nonylphenol and phenol. They share essentially the same head but nonylphenol has a nine-carbon alkyl tail and phenol has no clear tail. At zero surfactant density, a slip length of 1.2 nm exists at the brine–decane interface. As either surfactant is introduced to brine–decane interfaces, the slip length initially decreases linearly, with nonylphenol being more effective in reducing the slip length. As more surfactants are introduced, the decrease in slip length slows down and eventually, the slip length plateaus at −1.4 and −0.5 nm for interfaces populated with nonylphenol and phenol, respectively. The mechanisms of the observed slip length vs surfactant density relations and the effects of tail length on the interfacial slippage are elucidated by analyzing the molecular structure and transport of interfacial fluids and surfactants.
Capture and isolation of tumor cells by graphene intercalated carbon film
Authors: Ming Ruiqi , Yang Senyu , Jiang Ye , An Chunchun , Yang Yuhua , Diao Dongfeng , Cao Yuanyuan , Chen Tongsheng , Li Xinlei
Published: February 2022

We prepare a near-infrared responsive graphene intercalated carbon (GIC) substrate to capture and isolate tumor cells. The rough nanostructured morphology of a GIC substrate surface can enhance the interactions between cells and substrates, resulting in high efficiency capture of cells. Due to the good photothermal effect of the GIC substrate, combined with the temperature sensitivity of gelatin, tumor cells can be efficiently released under near infrared light irradiation. More importantly, no foreign substances were introduced into isolated cells in the whole process, thus maintaining high vitality of cells.
Requirement of Xk and Vps13a for the P2X7-mediated phospholipid scrambling and cell lysis in mouse T cells
Authors: Ryoden Yuta , Segawa Katsumori , Nagata Shigekazu
Published: February 2022

Significance

The extracellular concentration of adenosine triphosphate (ATP) reaches several hundred micromoles in the inflamed tissues or tumor environment. A high concentration of ATP activates P2X7, a purinergic receptor, and induces the formation of a nonselective cation channel, accompanied by reversible phosphatidylserine (PtdSer) exposure, leading to cell lysis. Here, we found that Xk and Vps13a complexed at plasma membranes are indispensable for ATP-induced PtdSer exposure and cell lysis. Patients with McLeod syndrome and chorea-acanthocytosis are known to carry the mutation in
XK
and
VPS13A
genes, respectively, suggesting that a defect of XK-VPS13A–mediated phospholipid scrambling is responsible for neuroacanthocytosis, a progressive movement disorder, and cognitive and behavior changes.
Plectin-mediated cytoskeletal crosstalk controls cell tension and cohesion in epithelial sheets
Authors: Prechova Magdalena , Adamova Zuzana , Schweizer Anna-Lena , Maninova Miloslava , Bauer Andreas , Kah Delf , Meier-Menches Samuel M. , Wiche Gerhard , Fabry Ben , Gregor Martin
Published: February 2022

The coordinated interplay of cytoskeletal networks critically determines tissue biomechanics and structural integrity. Here, we show that plectin, a major intermediate filament-based cytolinker protein, orchestrates cortical cytoskeletal networks in epithelial sheets to support intercellular junctions. By combining CRISPR/Cas9-based gene editing and pharmacological inhibition, we demonstrate that in an F-actin–dependent context, plectin is essential for the formation of the circumferential keratin rim, organization of radial keratin spokes, and desmosomal patterning. In the absence of plectin-mediated cytoskeletal cross-linking, the aberrant keratin–desmosome (DSM)–network feeds back to the actin cytoskeleton, which results in elevated actomyosin contractility. Also, by complementing a predictive mechanical model with Förster resonance energy transfer–based tension sensors, we provide evidence that in the absence of cytoskeletal cross-linking, major intercellular junctions (adherens junctions and DSMs) are under intrinsically generated tensile stress. Defective cytoarchitecture and tensional disequilibrium result in reduced intercellular cohesion, associated with general destabilization of plectin-deficient sheets upon mechanical stress.
Assessing Gq-GPCR–induced human astrocyte reactivity using bioengineered neural organoids
Authors: Cvetkovic Caroline , Patel Rajan , Shetty Arya , Hogan Matthew K. , Anderson Morgan , Basu Nupur , Aghlara-Fotovat Samira , Ramesh Srivathsan , Sardar Debosmita , Veiseh Omid , Ward Michael E. , Deneen Benjamin , Horner Philip J. , Krencik Robert
Published: February 2022

Astrocyte reactivity can directly modulate nervous system function and immune responses during disease and injury. However, the consequence of human astrocyte reactivity in response to specific contexts and within neural networks is obscure. Here, we devised a straightforward bioengineered neural organoid culture approach entailing transcription factor–driven direct differentiation of neurons and astrocytes from human pluripotent stem cells combined with genetically encoded tools for dual cell-selective activation. This strategy revealed that Gq-GPCR activation via chemogenetics in astrocytes promotes a rise in intracellular calcium followed by induction of immediate early genes and thrombospondin 1. However, astrocytes also undergo NF-κB nuclear translocation and secretion of inflammatory proteins, correlating with a decreased evoked firing rate of cocultured optogenetic neurons in suboptimal conditions, without overt neurotoxicity. Altogether, this study clarifies the intrinsic reactivity of human astrocytes in response to targeting GPCRs and delivers a bioengineered approach for organoid-based disease modeling and preclinical drug testing.
Chromatic Picard groups at large primes
Authors: Pstrągowski Piotr
Published: February 2022

We show that the Hopkins’ Picard group of the

K
(
n
)

K(n)

-local category coincides with its algebraic approximation when

2
p
−
2
>

n

2

+
n

2p-2 > n^{2}+n

.
Corrigendum to “Brauer characters of 𝑞′- degree”
Authors: Lewis Mark , Tong-Viet Hung
Published: February 2022

In this corrigendum, we correct some errors in our proofs of part (ii) of Lemma 2.6 and Claim (5) of Theorem 2.7 in [Proc. Amer. Math. Soc. 145 (2017), pp. 1891–1898].
An elastic flow for nonlinear spline interpolations in ℝⁿ
Authors: Lin Chun-Chi , Schwetlick Hartmut , Tran Dung
Published: February 2022

In this paper we use the method of geometric flow on the problem of nonlinear spline interpolations for non-closed curves in

n
n

-dimensional Euclidean spaces. The method applies theory of fourth-order parabolic PDEs to each piece of the curve between two successive knot points at which certain dynamic boundary conditions are imposed. We show the existence of global solutions of the elastic flow in suitable Hölder spaces. In the asymptotic limit, as time approaches infinity, solutions subconverge to a stationary solution of the problem. The method of geometric flows provides a new approach for the problem of nonlinear spline interpolations.
Noncommutative Christoffel-Darboux kernels
Authors: Belinschi Serban , Magron Victor , Vinnikov Victor
Published: February 2022

We introduce from an analytic perspective Christoffel-Darboux kernels associated to bounded, tracial noncommutative distributions. We show that properly normalized traces, respectively norms, of evaluations of such kernels on finite dimensional matrices yield classical plurisubharmonic functions as the degree tends to infinity, and show that they are comparable to certain noncommutative versions of the Siciak extremal function. We prove estimates for Siciak functions associated to free products of distributions, and use the classical theory of plurisubharmonic functions in order to propose a notion of support for noncommutative distributions. We conclude with some conjectures and numerical experiments.
Safety and Performance of POLYTECH Mesmo Breast Implants: A 5-Year Post-market Surveillance Study on 919 Patients
Authors: Montemurro Paolo , Siri Giacomo , Clerico Luana
Published: February 2022

Background

In 2007, POLYTECH Health & Aesthetics (POLYTECH, Dieburg, Germany) established an ongoing patient survey to improve the post-market surveillance of silicone gel-filled breast implants based on patient-reported outcomes in the context of the pioneering “Implants of Excellence” (IoE) program.

Objectives

To disclose an update on safety and performance outcomes at 5 years for Mesmo breast implants.

Methods

Between January 2014 and October 2019, 919 patients (for a total of 1816 implants) who underwent breast augmentation and reconstruction with Mesmo implants were asked to participate in the IoE program. Data were collected by mean of 1320 questionnaires received. A survival analysis assessed the onset of different complications.

Results

Eight patients (0.9%) experienced capsular contracture Baker grade III or IV with a cumulative rate at 5 years of 1.2% (95% CI = 0.6-2.4). The proportion of revisional surgery was 0.5% with a 5-year rate of 0.6% (95% CI = 0.2-1.5). Additional adverse events such as hematoma, seroma, malposition, open wounds, and other complications were carefully monitored. Questionnaires showed that 93.9% (95% CI = 92.2-95.4) of the patients were satisfied or very satisfied with their aesthetic results with Mesmo implants.

Conclusions

Post-market clinical follow-up revealed that the overall complications rate reported was low. Data demonstrated an excellent safety property on a large cohort of patients. This result allows the rating of Mesmo breast implants as highly competitive and a very safe choice for both surgeons and patients.

Level of Evidence: 3
Immune microenvironment characteristics and their implications for immune checkpoint inhibitor efficacy in HER2-overexpressing gastric cancer
Authors: Cen Shuyi , Xu Haimiao , Liu Zhen , Zhao Rongjie , Pan Hongming , Han Weidong
Published: February 2022

HER2-positive gastric cancer is a distinct tumor subtype, accounting for ~10% of gastric cancer cases. It is characterized by HER2 overexpression and responds well to HER2-targeting therapies. Recently, the addition of immune checkpoint inhibitors to HER2-targeting therapies produced satisfactory outcomes in these patients. In the present study, we used gene expression profiles and patient surgical sections to analyze the tumor immune microenvironment characteristics of gastric tumors with high HER2 expression. Several differentially enriched pathways were identified between the HER2 high-expression group and the low-expression group, such as pathways related to cytokine–cytokine receptor interactions, calcium signaling, and cell adhesion molecules. Tumors with high HER2 expression comprised fewer stromal cells and fewer immune cells, and had higher tumor purity. They also presented with lower expression of PD-1, PD-L1, CTLA-4, TIGIT, and LAG-3. In conclusion, our study provides a comprehensive blueprint of the immune microenvironment of HER2-positive gastric tumors. This analysis highlights the importance of considering the tumor microenvironment when assessing response to immune checkpoint inhibitors.
The absence of B cells disrupts splenic and myocardial Treg homeostasis in coxsackievirus B3-induced myocarditis
Authors: Lu Jing , Cen Zhihong , Tang Quan , Dong Jingwei , Qin Lin , Wu Weifeng
Published: February 2022

Although B cells are essential for humoral immunity and show noteworthy immunomodulatory activity through antibody-independent functions, the role of B cells in regulating Treg cell responses remains controversial. Tregs (CD4+CD25+Foxp3+) are considered to play an immunoprotective role in viral myocarditis (VMC) by controlling autoimmune effector T cells. Here, we proved that B-cell knockout can not only lead to significant reductions in Tregs in the spleen, blood, and heart of VMC mice but also decrease the activation and immune function of splenic Tregs, which was reversed by adoptive transfer of B cells; the transcription levels of TGF-β and Foxp3 in the myocardium were also significantly reduced. B-cell depletion by anti-CD20 impaired the anti-inflammatory function of splenic Tregs and the homeostasis of myocardial Tregs population. Moreover, B cells can convert CD4+CD25− T cells into Foxp3+ and Foxp3−, two functionally suppressive Treg subgroups. Although the reduction in myocardial inflammation in BKO mice indicates that B cells may play a proinflammatory role, the beneficial side of B cells cannot be ignored, that is, to control autoimmunity by maintaining Treg numbers. The results observed in the animal model of VMC highlight the potential harm of rituximab in the nonselective depletion of B cells in clinical applications.
P632 Estimating indirect and out-of-pocket disease-associated costs in paediatric Inflammatory Bowel Disease: a nation-wide cross-sectional analysis
Authors: El-Matary W , Witt J , Bersnstein C , Jacobson K , Mack D , Otley A , Walters T , Huynh H , deBruyn J , Griffiths A , Benchimol E
Published: February 2022

Background

Identifying disease-related costs is a crucial step to plan for proper allocation of resources and future healthcare services for persons with inflammatory bowel disease (IBD). Data on paediatric inflammatory bowel disease-associated costs are limited. We aimed to estimate indirect and out of pocket (OOP) paediatric IBD-associated costs in Canada.

Methods

In a nation-wide cross-sectional analysis, caregivers of children and young adults (<17 years) with IBD were invited to complete a questionnaire on lost work hours and OOP costs related to IBD in the 4 weeks prior to the survey. Participants were re-invited to periodically answer the same questionnaire every 3–9 months for 2 years. Lost productivity was calculated using the Human Capital method. Costs were reported in 2018 inflation-adjusted Canadian dollars. Predictors of high cost users (top 25%) were examined using negative binomial regression.

Results

Consecutive 243 (82 incident cases) of 262 (92.7%) approached participants completed the first survey with a total of 450 surveys longitudinally completed over 2 years. The annual median indirect costs per patient were $5,951 (IQR $1,812- $12,278), with $5,776 (IQR $1,465-$11,733) for Crohn Disease (CD) and $6,084 (IQR $2,470-$13,371) for Ulcerative Colitis (UC) (p=0.77). The annual median per patient OOP costs were $2,925 (IQR $978- $8,125) with $3,021 (IQR $978- $8,125) for CD and $2,600 (IQR $975- $8,125) for UC (p=0.55). Older age (10-17y) at diagnosis (p=0.04) and parents in part-time employment (p=0.01) were predictors of higher indirect costs, while female sex (p<0.001), parents with a lower education level (p<0.001) and lower annual family income (p<0.01) were associated with higher OOP costs.

Conclusion

Indirect and OOP IBD-associated costs are substantial and more likely to affect families with unstable employment and lower annual income. Examining different strategies and interventions to reduce these costs such as virtual platforms, telephone and outreach clinics especially in poor communities and families with low annual income is warranted.
The prognostic value of reduced global longitudinal strain (GLS) on cardiac outcomes in patients on peritoneal dialysis: a prospective study
Authors: Kam K , Ng JKC , Kwong VWK , Szeto CC , Lee APW
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Introduction

This study aims to evaluate the capacity of left ventricular global longitudinal strain (GLS) in end stage renal failure patients on peritoneal dialysis (PD) to predict cardiovascular mortality and major adverse cardiac events (MACE). GLS has been an established parameter in detecting subclinical left ventricular systolic dysfunction in the setting of preserved ejection fraction (EF > = 50%). We hypothesized that reductions of GLS (i.e. less negative value) are associated with adverse cardiovascular outcome.

Methods

We prospectively recruited a total of 60 PD patients from a single dialysis center in a tertiary hospital. GLS was determined by two-dimensional speckle-tracking echocardiography, under Philips QLab system. A less negative value reflects underlying subclinical LV dysfunction. The primary outcome was 4-point MACE, which was a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke and hospitalization for heart failure. Surrogate markers of inflammation (C-reactive protein [CRP], tumor necrosis factor [TNF]-alpha), nutrition (serum albumin), arterial stiffness (pulse wave velocity [PWV]), and serum N-terminal pro-brain natriuretic peptide (NT-proBNP) were also measured.

Results

16 (26.7%) and 34 (56.7%) PD patients had reduced GLS (≥ -18.3%) and left ventricular hypertrophy (LVH) respectively. In 12-month follow up, 4-point MACE occurred in 13.6% and 59.8% of normal and compromised GLS patients respectively (log-rank, P = 0.004), as illustrated by Kaplan-Meier curves (Fig 1). Patients with reduced GLS had higher proportion of uncontrolled blood pressure and higher prevalence of coronary artery disease. Their EF were significantly lower (53.6 ± 7.4% vs. 61.3 ± 4.1%, P= 0.001) compared with patients with normal GLS. In addition, GLS correlated with EF (r = -0.57, P <0.0001) and PWV (r= 0.33, P = 0.01). There was a trend towards an association between GLS and ln(CRP) (r= 0.25, P = 0.057), and ln(NT-proBNP) (r = 0.22, P= 0.09), respectively.

Conclusions

Subclinical LV systolic dysfunction was present in one-fourth of peritoneal dialysis patients despite having preserved EF. Reduced GLS (less negative than 18.3%, illustrated in Fig 2) is a strong predictor of poor cardiovascular prognosis among PD population. Abstract Figure 1  Abstract Figure 2
The effect of exercise on left ventricular global longitudinal strain: a systematic review and meta-analysis
Authors: Murray J , Bennett H , Bezak E , Perry R , Boyle T
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Cancer Research Institute, Allied Health and Human Performance, University of South Australia

Background/Introduction

Left ventricular global longitudinal strain (LVGLS) can detect early myocardial changes prior to clinical abnormalities arising, and is a strong prognostic indicator of future cardiovascular (CV) dysfunction and mortality. It is well established that exercise improves CV function and reduces risk of CV disease. However, the impact of exercise on LVGLS is currently unclear. If LVGLS increases in response to habitual exercise, it could offer a sensitive measure that can determine the effectiveness of an exercise regime on CV health.

Purpose

The aim of this systematic review and meta-analysis was to determine whether exercise impacts LVGLS across a range of healthy and diseased populations.

Methods

Four databases (Medline, Scopus, eMbase, SPORTDiscus) were searched in November 2020. Included studies assessed LVGLS before and after an exercise intervention (minimum 2 weeks) in adults aged 18 years and over, and were published in English from 2000 onwards. Random-effects meta-analyses were performed at a study level using Stata (v16.1) to calculate summary standardized mean differences (SMD) and 95% confidence intervals (CI). 39 studies met selection criteria, with 35 included in meta-analyses (1765 participants).

Primary meta-analyses included only studies that compared outcomes between one or more intervention arms to a standard (non-exercising) control arm (RCT’s, N-RCT’s, randomised crossover). Secondary analyses included data from studies with intervention arms only (single group pre-post studies, intervention group from RCT’s, N-RCT’s, randomised crossover).

Results

Primary:

In populations with CV disease, a moderate effect of exercise was observed compared to non-exercising controls (SMD = 0.59; 95% CI, 0.16-1.02; p = 0.01 – figure 1a). No significant effect of exercise was observed for CV risk (SMD = 0.07; 95% CI, -0.15-0.29; p = 0.56 – figure 1b) and healthy (SMD = -0.20; 95% CI, -0.73-0.33; p = 0.45) populations compared to non-exercising controls.

Secondary

In secondary meta-analyses, significant effects of exercise were observed in CV disease (SMD = 0.26; 95% CI, 0.07-0.46; p = 0.01), CV risk (SMD = 0.54; 95% CI, 0.15-0.93; p = 0.01), chronic kidney disease (SMD = 0.65; 95% CI, 0.03-1.28; p = 0.04) and athletic (SMD = 0.30; 95% CI, 0.20-0.41; p= <0.001) populations.

Conclusion(s)

Increases in LVGLS observed in populations with CV disease may assist the prevention of secondary CV events. Secondary findings may support the use of exercise across a range of populations to increase LVGLS and enhance CV function. Future research must address the methodological limitations that currently exist, including improving upon study designs and reporting of individual data. Abstract Figure.
Non-invasive myocardial work indices in arterial hypertension: relevance to hypertension grade assessed by 24-hour blood pressure monitoring
Authors: Kolesnyk M , Dudko O
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Background. A novel approach to non-invasive myocardial work (MW) assessment was shown to be of clinical value in different scenarios. It based on left ventricle (LV) pressure-global longitudinal strain (GLS) loops computation. Systolic LV pressure is assumed to be equal to brachial cuff systolic pressure. However, single blood pressure (BP) measurement during echocardiography may be influenced by many factors, e.g. «white-coat» effect. The purpose of this study was to evaluate MW indices in patients from mild to severe arterial hypertension (AH) assessed by 24-hour ambulatory blood pressure monitoring.

Methods. The study enrolled 90 males (mean age 47 ± 9 years) with uncomplicated arterial hypertension (AH), divided into 3 groups (mild AH, moderate AH, severe AH). All patients underwent conventional echocardiography, speckle tracking echocardiography with LV pressure-strain loops computation and 24-hour BP monitoring at the same day. The AH grade was assessed by DABL criteria. MV indices were calculated with specific software by integrating LV global longitudinal strain data and non-invasively estimated LV pressure. The following parameters were calculated: global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE). The values are given as median and interquartile range.

Results. The patients in groups were comparable by demographic and clinical characteristics. We didn"t find any difference between groups by conventional echocardiographic parameters, including LV wall thickness, LV mass index, LV ejection fraction and LV GLS. The significant difference was present between three groups in all MW indices (Table). The patients with severe AH had higher GWI, as well as GCW and GWW compared to patients with mild and moderate AH. The GWE was significantly decreased in patients with highest BP values.

Conclusions. Myocardial work indices are more sensitive markers of LV function in patients with AH compared to standard parameters. Integration of systolic BP, assessed by 24-hour BP monitoring in MW analysis may potentially give more precise characteristics of LV function in hypertensive patients. Abstract Figure.
Right ventricular involvement in breast cancer patients undergoing chemotherapy
Authors: Ferri L , Bergamini C , Niro L , Springhetti P , Cerrito LF , Schiavone A , Dal Porto M , Setti E , Benfari G , Rossi A , Fiorio E , Ribichini FL
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Background

Trastuzumab (TZ) and Anthracyclines (AC) are widely used for their key role in breast cancer. However, they may have different side effects on the cardiovascular system. One of the most concerning complications is myocardial dysfunction. Many studies have highlighted the importance of the screening for cardiotoxicity using left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). Nevertheless, there is little data about the right ventricular (RV) involvement.

Purpose

Aim of this study is to analyze the modification of RV systolic function in this setting. 

Methods

105 women affected by HER-2 positive breast cancer treated with TZ referring to our echo-lab were enrolled in our single center prospective study. 3 patients were excluded due to an early TZ suspension not related to cardiovascular complications, thus 102 patients (97,1%) were eligible for analyses. 86 of these (84,3%) were treated also with AC. All patients underwent consecutive transthoracic echocardiography (TTE) before starting TZ and then every 3 months up to 12 months. 2D-Speckle tracking analysis was performed at baseline and at each examination using Tomtec software. A complete clinical evaluation was also performed at each follow up. LV systolic dysfunction was defined as an absolute reduction  of LVEF >10% from baseline to LVEF <53% or a relative reduction of GLS >15% from baseline and a reduction of LVEF >10% from baseline. RV systolic dysfunction was defined as TAPSE <17 mm, pulsed doppler S wave  <9,5 cm/s and/or RV free wall strain <20%.

Results

LV systolic dysfunction occurred in 11 patients (10,8%).  TAPSE and pulsed doppler S wave remained within the normal limits in all patients at follow up. On the contrary, RV free wall strain was reduced in 11 patients (10,8%), none of whom reported symptoms or signs of right-sided heart failure; 5 of these (45,5%) also presented LV dysfunction . LV and RV systolic dysfunction occurred mainly at the same time. 

Conclusions

Cancer treatment also appears to impact on right chamber myocardium. RV free wall strain analysis seems more reliable in detecting RV systolic dysfunction rather than clinical examination or common echocardiographic parameters, such as TAPSE or pulsed doppler S wave, in the setting of patients with breast cancer treated with chemotherapy. However, further studies are needed to investigate its prognostic role.
Assessment of left ventricular contractile reserve during hyperventilation and exercise in patients with ANOCA
Authors: Dedic S , Boskovic N , Giga V , Nedeljkovic I , Tesic M , Jovanovic I , Aleksandric S , Beleslin B , Ciampi Q , Picano E , Djordjevic Dikic A
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Introduction. Mechanism of ischemia in patients with angina and no obstructive coronary artery disease (ANOCA), is often unrecognized since invasive tests are seldom done and proper noninvasive test is not established yet.

The aim of our study was to assess changes in ventricular function during hyperventilation test  (HYP) designed to provoke vasoconstriction, immediately followed by supine bicycle exercise to increase ischemic stimuli in patients with ANOCA (HYP + EXE).

Methods. : In a prospective study, we enrolled 29 ANOCA patients  (age 59.6 ±11 years, 27 females) with previously normal angiograms. All patients underwent SE testing with hyperventilation (HYP, respiratory rate of 30 per min for 5"), immediately followed by supine bicycle exercise (HYP + EXE). Ventricular function was assessed based on left ventricular contractile reserve (LVCR), calculated by ratio of the ventricular force at the peak of the each stress level and rest. Force was assessed as the quotient between systolic arterial pressure and end-systolic volume determined by two-dimensional echocardiography. Values range from normal (> 2.0) to mild (1.5–2.0), moderate (1.01–1.49), and severe (≤1.0) dysfunction. For LVCR HYP values are shifted towards lower values (abnormal < 1.1).

Results. Chest pain or dyspnea were present in 4/29 pts during HYP, and in 7/29 patients during HYP + EXE (13.8% vs 24.1 %, p = 0.001). Three patients showed wall motion abnormalities with hyperventilation and additional two patients with HYP + EXE. LVCR HYP response was normal in 19/29 (65.5%) pts and abnormal in 10/29 (34.5%) pts. LVCR HYP + EXE response was normal in 9/29 (31%) pts, 4/29 (13.8%) pts had mild, 11/29 (37.9%) pts had moderate and 5/29 (17.3%) pts had severe dysfunction.

Conclusion. In patients with ANOCA subtle changes in LV function occurred with HYP and EXE stress more often than wall motion abnormality. Measurement of contractile reserve might be a useful tool in assessment of ischemia and ventricular dysfunction in patients with ANOCA. Abstract Figure 1.  Abstract Figure 2.
Dobutamine 3D strain in the left anterior descending subtended ventricular territory: evidence for relationship with the respective velocity flow reserve
Authors: Armenis I , Armenis I , Demerouti E , Demerouti E , Athanassopoulos GD , Motsi A , Athanassopoulos GD
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Introduction

Three dimensional speckle tracking imaging (3DST), provides an evolving means to interrogate left ventricular (LV) function. However, its clinical application still remains limited.

Purpose

Purpose of the study was to interrogate the relationship between regional deformation by 3DST in left anterior descending artery (LAD) subtended territory and the respective coronary flow reserve (CFR).

Methods

Fifty patients aged 63 ± 6 years with chronic coronary syndromes were studied. Patients had no evidence of dobutamine (DOB) induced ischemia in LAD territory. Distal LAD CFR was estimated by adenosine Doppler echo (140mg/kg/min). 3DST derived integral strain (IS) and respective components (longitudinal -LS, circumferential –CS, radial -RS) were estimated by a full volume sweep (3.5 MHz sector probe) at >20 volumes/sec. A 16 LV sectors (sc) polar map was provided (Artida,Toshiba) with 10/16 sectors (sc) analysed, 6 sc being the conventional LAD territory (sc: 3,4,5,6,7,8) and another 4 sc being adjacent ones (sc: 1, 2, 9, 10). 3D datasets acquired at rest (R) and low dose DOB (20mg/kg/min). LV mass was automatically measured from volumetric data sets and its variability during cardiac cycle was considered as an index of coherence for true LV borders recognition.

Results

CFR was >2 in all pts (range 2.0-4.2, 2.74 + 0.46). Mean variability of LV mass between R and DOB was 0.044 (range: -0.090-0.008, p = ns). 3DST strain was related with LAD CFR as follows:

1.For IS: at R: sc1: r = 0.38, p = 0.023, sc3: r = 0.44, p = 0.006, sc5: r = 0.35, p = 0.03, sc9: r = 0.50, p = 0.002.

At DOB

sc7: r = 0.31, p = 0.05.

2.For LS: at R: sc5: r=-0.40, p = 0.01.

3.For CS: at R: sc5: r=-0.33, p = 0.02, sc5: r=-0.46, p = 0.004.

4.For RS: at R: sc9: r=-0.38, p = 0.08.

The % changes of regional IS post DOB compared to R were also related with CFR LAD in the sectors sc1 and sc3 (r = 0.34, p = 0.05, and p = 0.40, p = 0.002 respectively).

Conclusion

3DST derived LV deformation indices in the LAD territory are related with the respective CFR. LV regional integral strain has a stronger relationship with LAD CFR when compared to the partial vectors. The 3DST derived deformation indices seem sensitive enough to reproduce the flow function relationship in the LAD territory. Thus, potential applicability has to be supported.
The role of right ventricular longitudinal function in non-responder patient following cardiac resynchronization therapy
Authors: Jenei C , Toth A , Nagy L , Clemens M , Papp E , Csanadi Z
Published: February 2022

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Hungarian Government Research Fund, Szív- és érkutatási kiválóságközpont (IRONHEART)

Background

In approximately 30-40% of cases, the left ventricular systolic function does not improve following cardiac resynchronization therapy (CRT; non-responders). Currently, the role of right ventricular (RV) systolic function is yet not well established. Our aim was to assess the RV systolic function with 3D echocardiography in CRT patients.

Methods

We involved 24 patients (12–12 CRT responder and non-responder) who received CRT in our department, and whose 1-year follow-up data were available. We considered the patients "responder" when the left ventricular ejection fraction (LV EF) improved with at least 10% after CRT implantation. We characterized several 3D and 2D parameters of RV using a dedicated RV analysis software, such as RV ejection fraction (EF), body surface area-indexed end-diastolic (EDVi) and end-systolic (ESVi) volumes, free-wall longitudinal (RV GLS) and radial strains.

Results

After the follow-up, LV EF was 43 ± 8% in responders and 26 ± 7% in non-respoders (p < 0.0001). RV EF was significantly higher (EF: 44 ± 9%; p = 0.003) in responders compared to non-reponders (EF: 32 ± 9%). There was no significant difference in RV EDVi: 65 ml/m² (IQR: 54-74) in responders and 53 ml/m2 (IQR: 42-67) in non-responders (p = 0.22). RV ESVi was also comparable between CRT responders (37 ml/m² - IQR: 28-39) and non-responders (36 ml/m² - IQR: 28-46), (p = 0.85). RV GLS was significantly higher in CRT responders (-13 ± 3% vs. -10 ± 4% in non-responders; p = 0.02) in parallel with the change of the RV EF, while the RV radial strains did not differ between the two groups (2.5 ± 1.7% in responders vs. 2 ± 1% in non-responders; p = 0.47).

Conclusions

The lower RV EF based on mainly the longitudinal function of RV indicates non-respondence to CRT, however, it is not associated with RV dilation, i.e. adverse remodelling. These results suggest mechanical abnormality of RV function in the background of impaired EF.
Echocardiographic assessment of ventricular function in chronic HCV patients receiving direct antiviral therapy
Authors: Ghoneim MA , Magdeldin Mohamed Abdelgawwad I , Tageldin A , Nasr GM
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Hepatitis C virus (HCV) infection is still a major public health burden in many parts of the world (1). Globally, an estimated 58 million people have chronic hepatitis C virus infection, with about 1.5 million new infections occurring per year (2).

Treatment for chronic HCV infection has evolved from interferon (IFN)-based therapy to direct-acting antivirals (DAAs) (3,4). With the development of DAA, treatment of HCV became better-tolerated and highly effective (5,6).

Several studies have attempted to explore their cardiac side effects, especially their impact of left ventricular (LV) function; however, these studies were limited by their design and the methods of assessment (7-10).

Aim

 In this prospective study we aimed at evaluating the short effects of DAAs on left ventricular functions using 3D Echocardiography.

Methods

 Patients with HCV infection planned to receive combination therapy of Sofosbuvir 400 mg daily plus Daclatasvir 60 mg daily for 12 weeks were assessed by echocardiography before starting and after 3 months after completion of treatment. Patients with other systemic or cardiac conditions or structural heart disease were excluded.  Assessment of LV volume and EF was performed by 3D quantification and global longitudinal strain (GLS). Right ventricle size was assessed by 2D and systolic function was evaluated by TAPSE, S` and FAC.

Results

In 102 patients who were followed up at 3 months after DAA therapy, We found an increase in increase in both LV end diastolic dimensions and volumes (p∼0.02 & p∼0.045 respectively) as well as end systolic volumes (p∼0.005). There was no significant difference in neither LV systolic function as assessed by EF and GLS (62.25 ± 5.15 vs. 62.35 ± 5.77, p∼0.850, -22.97 ± 2.93 vs. -22.83 ± 2.59, p∼0.546 respectively), nor in diastolic function (p∼0.546). However, subgroup analyses revealed a significant negative correlation between age and GLS (P∼0.022) as well as the number of cardiovascular risk factors (P∼0.039). Hypertension was found to be the only predictor of the decrease in GLS in the regression analysis of risk factors (p∼0.001). There was no significant change in RV size and systolic function at follow up.

Conclusions

 There was no significant change in LV systolic or diastolic function before and after DAA therapy as measured by EF and GLS. Nonetheless, subgroup analysis suggests a drop in GLS in older patients and those with more cardiovascular risk factors. An increase in LV size was also noted while no significant effect was noted with regards to RV size and function.
Tricuspid annular plane systolic excursion (TAPSE) is not an appropriate parameter for the evaluation of right ventricular systolic function after lung transplant
Authors: Serrano Lozano D , Ruisanchez Villar C , Cuesta Cosgaya JM , Lerena Saenz P , Mora Cuesta VM , Iturbe Fernandez D , Lozano Gonzalez M , Zubiaur Zamacola J , Margarida De Castro A , Molina San Quirico M , Fernandez Rozas S , Vazquez De Prada Tiffe JA , Gonzalez Vilchez F , Cifrian Gonzalez JM
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Introduction. Tricuspid annular plane systolic excursion (TAPSE) is a widely used parameter for the assessment of right ventricular (RV) systolic function in candidates for lung transplant (LT). However, its accuracy after surgery is not well established. In our study, we aim to evaluate the feasibility of TAPSE after LT and compare it with other classic parameters of RV function.

Methods. 144 patients underwent LT between January 2014 and June 2017 in our center. Mean age was 55 years (65 % men). Double LT was performed in 65%, being most common etiology pulmonary fibrosis followed by chronic pulmonary obstructive disease. 9% of LT candidates had severe pulmonary hypertension (PH), defined as mean pulmonary artery pressure (PAP) over 45 mmHg on right heart catheterization.

We retrospectively analyzed echocardiographic studies at baseline and 4 weeks after LT in 94 patients. Nine of them had prior severe pulmonary hypertension. We measured RV fractional area change (FAC) and systolic displacement of tricuspid annulus-TAPSE as main parameters of RV systolic function, as well as right atrium (RA) area.

Results. We found a significant improvement in RV FAC (39 ± 9% vs. 44 ± 6%, p < 0.001) and a reduction in RA area (16 ± 6 cm2 vs. 12 ± 5 cm2; p < 0.001) after lung transplant in the global study group. This was remarkably significant when prior severe pulmonary hypertension was present (RV FAC 24 ± 9% vs. 43 ± 6%, RA area 27 ± 8 cm2 vs. 14 ± 4 cm2; p < 0.000). However, postoperative TAPSE was significantly lower (21 ± 3 mm vs. 17 ± 2 mm; p < 0.000), and it did not show any significant change in the PH subgroup (p = 0.89). We found a good correlation between TAPSE and RV FAC on pre-transplant echocardiographic study (r = 0.76; p < 0.000), whereas this relation did not remain after LT (r = 0.26; p 0.06).

Conclusion. Right ventricular systolic function globally improved after LT, and this is particularly pronounced in candidates with severe PH. In contrast, TAPSE paradoxically deteriorates on post-surgery echocardiogram. According to our findings, TAPSE may not be a reliable parameter for the assessment of RV systolic function after lung transplant.
Aortic valve calcification and endomyocardial fibrosis determine adverse outcomes following transcatheter aortic valve replacement
Authors: Evertz R , Hub S , Beuthner B , Backhaus S , Lange T , Topci R , Toischer K , Kowallick J , Puls M , Zeisberg E , Hasenfuss G , Schuster A
Published: February 2022

Funding Acknowledgements

Type of funding sources: None.

Aims

There is evidence to suggest that subtype of aortic stenosis (AS), degree of myocardial fibrosis (MF) and level of aortic valve calcification (AVC) are associated with adverse cardiac outcome in AS. Since little is known about their respective contribution, we sought to investigate their relative importance and interplay as well as association with adverse cardiac events.

Methods

100 consecutive patients with severe AS and indication for transfemoral transcatheter aortic valve replacement (TAVR) were prospectively enrolled between January 2017 and October 2018. Patients underwent transthoracic echocardiography, multi detector computed tomography (MDCT) and left ventricular endomyocardial biopsy at the time of TAVR.

Results

The final study cohort consisted of 92 patients with completed study protocol comprising of 39 (42.4 %) normal ejection fraction high gradient (NEFHG), 13 (14.1 %) low EF high gradient (LEFHG), 25 (27.2 %) low EF (flow) low gradient (LEFLG) and 15 (16.3 %) paradoxical low flow low gradient (PLFLG) AS. The high gradient phenotypes (NEFHG and LEFHG) showed the largest amount of AVC (807 ± 421; 813 ± 281 mm³ respectively) as compared to the low gradient phenotypes (LEFLG and PLFLG; 503 ± 326; 555 ± 594 mm³ respectively, p < 0.05). Conversely, MF was most prevalent in low output phenotypes (LEFLG > LEFHG > PLFLG > HEFHG, p < 0.05). This was paralleled by larger cardiovascular mortality within 600 days post TAVR (LEFLG n = 7 > PLFLG n = 4 > LEFHG n = 2 > NEFHG n = 1). In Patients with high MF burden a higher AVC was associated with a lower mortality (p = 0.045, HR = 0.261, 95%CI 0.07-0.97). Within LEFLG AS, patients with larger AVC (>476.8 mm³) had larger MF (40.2%) and higher cardiovascular mortality (n = 5) as compared to patients with lower AVC (£476.8 mm³, 17.1% MF, p = 0.027, cardiovascular mortality n = 2).

Conclusion

MF is associated with adverse cardiovascular outcome following TAVR which is most prevalent in low ejection fraction situations. In the presence of large MF burden patients with large AVC have better outcome following TAVR. Conversely worse outcome in large MF and relatively little AVC may be explained by a relative prominence of an underlying cardiomyopathy while better survival rates in large AVC patients may indicate severe AS associated pressure overload relief and subsequently improved survival following TAVR.