bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of polymer-derived SiC fiber
Authors: Dong Jun , Bai Weicheng , Huang Guiliang , Han Liang , Zhang Guangjun
Published: November 2020

The polymer—derived SiC fiber is one of the most important reinforcing materials for high performance ceramic matrix composites (CMC). Three generations of SiC fibers have been developed over the past thirty years. In this article, the preparing methods, compositions, microstructures and performances of three generation fibers are reviewed. Furthermore, the relationships are discussed between microstructure and the main properties of the fibers, such as high temperature-resistance and creep resistance. as a summary, some improving methods for the properties of SiC fibers derived from precursor are summarized.
Application of Polyoxometalate in Synthesis of 2,5-Diformylfuran and Its Derivatives
Authors: Li Zheng
Published: November 2020

Because of the inherent defects of fossil resources, replacing fossil resources with biomass resources is a great challenge in the 21st century. 2,5-Diformyl furan (DFF) and its derivatives are important value-added chemicals derived from biomass platform chemicals 5-hydroxymethylfurfural (HMF) and fructose, which have great application in the field of medicine, biopolymer and scientific research. It is of great significance to select suitable catalyst to complete the conversion. Polyoxometalate is anionic metal oxide clusters, due to their excellent thermal stability and redox ability, polyoxometalate are widely used in catalytic oxidation and have been gradually used in biomass value-added conversion. The preparation of DFF and its derivatives from HMF and fructose using polyoxometalate has become a research hotspot in recent years.
Research on the Effect of Different Esters on the Synthesis of Polycarboxylate Superplasticizer at Low Content
Authors: Yang Xiao Hong
Published: November 2020

This article uses three ester monomers, hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate (HEA), and hydroxypropyl acrylate (HPA), mixed with 2% of the mass of the macromonomer to synthesize Polycarboxylate Superplasticizer (PCE), compared with the blank sample without esters. The GPC technology was used to investigate the influence of different ester monomers on the molecular weight and distribution of PCE and the polymer yield at low dosages. The cement paste and concrete tests were carried out for testing the performance of PCE. Experiments proves that HEMA affects initial dispersion performance at low dosage. The article concludes that HEA and HPA indeed played a slow-release effect at low content.
Non-enzymatic electrochemical detection of glucose with and without the presence of insulin using rGO/ZnO
Authors: Belkhalfa Hakim , Bendjerad Adel , Dokhan Nahed , Lahmar Abdelilah , Rahmani Salima
Published: November 2020

In the present work, the combination of the electrophoretic deposition of ZnO nanostructures with size not exceeding 50 nm, and the reduced graphene oxide (rGO) on gold electrodes was performed to study the non-enzymatic electrochemical detection of glucose. The effect of insulin insertion on glucose detection and regulation was studied and the electrochemical responses were compared with and without this molecule. The results showed that the GO/insulin/ZnO electrode is much more sensitive for the glucose detection, in addition to its ability to drop the insulin protein hormone under a negative voltage. That bears interest as dual function sensor for detection and regulation of glucose.
Laser additive manufacturing of bimetallic structure from TC4 to IN718 via Ta/Cu multi-interlayer
Authors: Wang Chenyang , Shang Chun , Liu Zhanqi , Xu Guojian , Liu Xiangyu
Published: November 2020

Titanium alloys and nickel-based alloys have their own unique properties, and the bimetallic structure composed of the two alloys can be widely used in the aerospace field. However, the bimetallic structure which is fabricated by directly joining titanium alloys and nickel-based alloys via traditional methods is more sensitive to cracks due to the formation of intermetallic compounds. In this work based on laser additive manufacturing (LAM) technology, the TC4/IN718 bimetallic structure without metallurgical defects (such as cracks) was successfully fabricated via a Ta/Cu multi-interlayer. The test results indicated that the Ta/Cu multi-interlayer could effectively avoid the generation of Ti–Ni and Ti–Cu intermetallic compounds between TC4 and IN718. A good metallurgical combination was formed in each interface from TC4 to IN718 without metallurgical defects. The phase evolution from the TC4 region to the IN718 region was as follows: α-Ti → α-Ti + β-Ta → β-Ta → β-Ta + γ-Cu → γ-Cu → γ-Cu +γ-Ni + laves → γ-Ni + laves. The ultimate tensile strength of the bimetallic structure at room temperature was 369.32 MPa.
Effect of As and Ga doping on the electronic structure and photoelectric properties of cubic Ca2Ge
Authors: Lyu Lin , Yang Yinye , Cen Weifu , Yao Bing , Ou Jiankai
Published: November 2020

The electronic structure and optical properties of intrinsic and doped Ca2Ge have been calculated by using the first-principles calculation method based on density functional theory. The doping content of As were 2.08% and 1.04%, respectively, and the doping concentrations of Ga were same with As. The band gap of intrinsic Ca2Ge is 0.556 eV, and that decreased to 0.526 eV and 0.548 eV with respect of As doping amount of 2.08% and 1.04%. Meanwhile, the band gap is 0.25 eV when the doping amount of Ga was 1.04%, and the band gap is 0.23 eV for Ga was 2.08%. The band structures results shown that the Fermi levels of As-doped (2.08% and 1.04%) are moved into the bottom of conduction band. The electronic density of sates shown that the electronic configurations at the top valence band and bottom conduction band were changed as As and Ga doped. The dielectric function results shown that the maximum value of 52.7 and 97.53 were respectively obtained at 0 eV for the 2.08% Ga-doped and the 1.04% As-doped. Moreover, the phenomenon of strong metallic reflection has been found in the energy range of 6.0 ∼ 8.5 eV, and the metal reflection characteristics of intrinsic Ca2Ge was greater than the doped Ca2Ge. Analyzing the energy-loss function, it indicating that the energy region of appearing energy loss can be altered by doping As and Ga or changing their doped concentration.
Tackling solid tumour therapy with small-format drug conjugates
Authors: Deonarain Mahendra P , Xue Quinn
Published: November 2020

The pharmacokinetic–pharmacodynamic relationship is extremely complex and tumour drug penetration is one key parameter influencing therapeutic efficacy. In the context of antibody–drug conjugates (ADCs), which has undergone many innovation cycles and witnessed many failures, this feature is being addressed by a number of alternative technologies. Immunoglobulin-based ADCs continue to dominate the industrial landscape, but smaller formats offer the promise of more-effective cytotoxic payload delivery to solid tumours, with a higher therapeutic window afforded by the more rapid clearance. To make these smaller formats viable as delivery vehicles, a number of strategies are being employed, which will be reviewed here. These include identifying the most-appropriate size to generate the larger therapeutic window, increasing the amount of functional, cytotoxic payload delivered through conjugation or half-life extending technologies or other ways of extending the dosing without inducing toxicity.
What is “global Islam”?
Authors: Green Nile
Published: November 2020

“What is global Islam?” is a question of definition that, like global Islam itself, can be answered by first looking at what it is not. How does global Islam differ from world Islam? Global Islam is driven by methods used by transnational actors to spread messages worldwide, while world Islam flourishes away from communication networks. Before the “first globalization” with the rise of steam travel and the printing press, religious power and knowledge were largely concentrated in a group of Sunni leaders. Technology enabled new voices to challenge the established order. This challenge continues today via satellite channels, international societies and organizations, and online communities.
1865 and after the war
Authors: Masur Louis P.
Published: November 2020

“1865 and after the war” begins with the Confederacy taking desperate measures to try and reverse its fortunes. In March, Lincoln delivered his second inaugural and in April, Robert E. Lee and Ulysses S. Grant met at Appomattox to agree to the terms of surrender. Less than a week later, Lincoln was assassinated. In the aftermath, President Johnson battled with Congress over the terms of reconstruction. New amendments and educational initiatives helped freedmen, but their fortunes were mixed as Southern Democrats and former slave owners regained political power. In the 1870s, financial panic seized America, shifting the focus away from the South and bringing a close to the era of war and reconstruction.
1. No enzymes, no life
Authors: Engel Paul
Published: November 2020

‘No enzymes, no life’ discusses the role of enzymes and how they orchestrate the whole of life. Almost every chemical step in every living thing is guided by its own dedicated enzyme. Out of all the multitude of reactions that might theoretically be possible, enzymes select and guide the orderly sequences of reactions which are called ‘metabolism’, breaking down foodstuffs stepwise to give useful building blocks and reassembling them to make new biological molecules. Ultimately, enzymes control every biological process. Can chemistry explain biology?
2. How do volcanoes explode?
Authors: Branney Michael J. , Zalasiewicz Jan
Published: November 2020

‘How do volcanoes explode?’ examines how volcanoes explode, looking at the anatomy of an explosive eruption. It studies pumice-forming rhyolitic eruptions. One of the first things a volcanologist may do on arrival at a volcano is to figure out how the volcano has behaved in the past: what sort of eruptions, how large, and how frequent. Basaltic explosivity can be compared with rhyolitic and andesitic explosivity. Phoenix plumes rise from pyroclastic currents and contain mostly fine ash.
‘Their Voices Ring in My Ears’:Laura, the Fugue, and Adaptation
Authors: Toth Margaret A , Ramoni Teresa
Published: November 2020

This essay analyzes Vera Caspary’s novel Laura (1943) and the 1944 film adaptation (Preminger) in order to demonstrate an approach to adaptation studies we call fugal. If a fugue is a composition based on a ‘subject’ or short melodic phrase and its various ‘answers’—in other words, variations that maintain elements of the melody but also play with and revise it—how might we position the film as a variation on, rather than a reproduction of, Caspary’s novel? To explore this question, we analyze the sonic register of both the novel and film. Caspary doesn’t want us to merely read her novel; she wants us to listen to the voices that narrate it and the tunes that populate it. Similarly, listening to the film—not simply the dialogue but also the voiceover narration and David Raksin’s groundbreaking score—allows us to identify content not overt in, and sometimes at odds with, the visuals. When we listen critically and carefully, we can distinguish nuances that get lost in a strict fidelity approach; in particular, we can identify both works’ feminist content, especially their attempts to decentre patriarchal hard-boiled conventions and to confound notions of a singular truth.
Single-locus species delimitation and ecological niche modelling provide insights into the evolution, historical distribution and taxonomy of the Pacific chorus frogs
Authors: Jadin Robert C , Orlofske Sarah A , Jezkova Tereza , Blair Christopher
Published: November 2020

The Pacific chorus frogs are a complex of three wide-ranging species (i.e. Hyliola hypochondriaca, Hyliola regilla, Hyliola sierra) whose current taxonomy remains unresolved. We conducted species delimitation analyses of these taxa using fragments of the cytochrome b and 12S–16S mtDNA genes to assess the species diversity. Importantly, we included samples from new locations throughout the range to better understand species distributions and identify potential contact zones among clades. Our analyses revealed three slightly parapatric but distinct species-level clades. Molecular dating revealed that these species began diverging in the Pleistocene c. 1.4 Mya with H. hypochondriaca and H. sierra diverging more recently c. 0.8 Mya. We found that populations from western Montana and Idaho originated recently from populations to the southwest that belong to H. sierra, rather than from H. regilla populations directly to the west. Population sizes of each species expanded c. 130–80 Kya with H. hypochondriaca exhibiting a more pronounced expansion beginning c. 100 Kya than the more gradual expansion of the other two species. The climatic niche models suggest that distributions of the three species were similar during the last interglacial (LIG) as they are today. During the Last Glacial Maximum (LGM), H. hypochondriaca and H. sierra occupied a larger range than they do today whereas H. regilla occupied a smaller refugium, shifted south from the current distribution. This study highlights the continued effectiveness of utilizing single-locus data sets for species delimitation and biogeographic analyses.
Cortical Gyrification Morphology in Individuals with ASD and ADHD across the Lifespan: A Systematic Review and Meta-Analysis
Authors: Gharehgazlou Avideh , Freitas Carina , Ameis Stephanie H , Taylor Margot J , Lerch Jason P , Radua Joaquim , Anagnostou Evdokia
Published: November 2020

Autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) are common neurodevelopmental disorders (NDDs) that may impact brain maturation. A number of studies have examined cortical gyrification morphology in both NDDs. Here we review and when possible pool their results to better understand the shared and potentially disorder-specific gyrification features. We searched MEDLINE, PsycINFO, and EMBASE databases, and 24 and 10 studies met the criteria to be included in the systematic review and meta-analysis portions, respectively. Meta-analysis of local Gyrification Index (lGI) findings across ASD studies was conducted with SDM software adapted for surface-based morphometry studies. Meta-regressions were used to explore effects of age, sex, and sample size on gyrification differences. There were no significant differences in gyrification across groups. Qualitative synthesis of remaining ASD studies highlighted heterogeneity in findings. Large-scale ADHD studies reported no differences in gyrification between cases and controls suggesting that, similar to ASD, there is currently no evidence of differences in gyrification morphology compared with controls. Larger, longitudinal studies are needed to further clarify the effects of age, sex, and IQ on cortical gyrification in these NDDs.
Defining Galactomannan Positivity in the Updated EORTC/MSGERC Consensus Definitions of Invasive Fungal Diseases
Authors: Mercier Toine , Castagnola Elio , Marr Kieren A , Wheat L Joseph , Verweij Paul E , Maertens Johan A
Published: November 2020

The consensus definitions of invasive fungal diseases from the EORTC/MSGERC were recently revised and updated. They now include consensus cutoff values for the galactomannan test that support the diagnosis of probable invasive aspergillosis. In this supplement article, we provide a rationale for these proposed thresholds based on the test’s characteristics and performance in different patient populations and in different specimen types.
Artificial intelligence-guided image acquisition on patients with implanted electrophysiological devices: results from a pivotal prospective multi-center clinical trial
Authors: Surette S , Narang A , Bae R , Hong H , Thomas Y , Cadieu C , Chaudhry A , Martin R , Rubenson D , Goldstein S , Little S , Lang R , Weissman N , Thomas J.D
Published: November 2020

Background

A novel, recently FDA-authorized software uses deep learning (DL) to provide prescriptive transthoracic echocardiography (TTE) guidance, allowing novices to acquire standard TTE views. The DL model was trained by >5,000,000 observations of the impact of probe motion on image orientation/quality. This study evaluated whether novice-acquired TTE images guided by this software were of diagnostic quality in patients with and without implanted electrophysiological (EP) devices, focusing on RV size and function, which were thought to be sensitive to EP devices. Some aspects of the study have previously been presented.

Methods

240 patients (61±16 years old, 58% male, 33% BMI >30 kg/m2, 91% with cardiac pathology) were recruited. 8 nurses without echo experience each acquired 10 view TTEs in 30 patients guided by the software. 235 of the patients were also scanned by a trained sonographer without assistance from the software. 5 Level 3 echocardiographers independently assessed the diagnostic quality of the TTEs acquired by the nurses and sonographers to evaluate the effect of EP devices on DL software performance.

Results

Nurses using the AI-guided acquisition software acquired TTEs of sufficient quality to make qualitative assessments of right ventricular (RV) size and function in greater than 80% of cases for patients with and without implanted EP devices (Table). There was no significant difference between nurse- and sonographer-acquired scans.

Conclusion

These results indicate that new DL software can guide novices to obtain TTEs that enable qualitative assessment of RV size even in the presence of implanted EP devices. The results of the comparison to sonographer-acquired exams indicate the software performance is robust to presence of pacemaker/ICD leads visible in the images (Figure).

Nurse-acquired TTE with visible ICD lead

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Caption Health, Inc.
Prognostic role of coronary flow velocity reserve in hypertrophic cardiomyopathy
Authors: Tesic M , Ciampi Q , Djordjevic-Dikic A , Beleslin B , Cortigiani L , Palinkas A , Palinkas E , Nemes A , Rigo F , Borguezan-Daros C , Varga A , Agoston G , Villari B , Carpeggiani C , Picano E
Published: November 2020

Background

A reduction in coronary flow velocity reserve (CFVR) related to coronary microvascular dysfunction is a major mechanism for ischemia in hypertrophic cardiomyopathy (HCM).

Hypothesis

To assess the functional correlates and prognostic value of CFVR during stress echocardiography (SE) in HCM.

Methods

We enrolled 201 HCM patients (age 51±14 years, 105 male, 52%; maximal wall thickness: 18±3 mm) studied with CFVR during exercise (n=33, 16.4%), dipyridamole (n=89, 44.3%) or adenosine (n=79, 39.3%) SE in 6 certified centers. CFVR was assessed using pulsed wave Doppler sampling in left anterior descending coronary artery. All patients completed the clinical follow-up.

Results

During SE mean value of CFVR was 2.11±0.46. No patients showed regional wall motion abnormalities during stress. LV outflow tract obstruction (LVOTO) was present in 34 (16.9%) patients at rest and in 47 (23.4%) at peak stress. CFVR was inversely related to age (r=−0.229, p=0.001) and maximal wall thickness (r=−0.197, p=0.031). During a median follow-up of 26 months (IQ range: 12–48 months), 75 events in 63 patients occurred: 10 deaths, 33 new hospital admission for acute heart failure, 8 sustained ventricular tachycardias and 24 atrial fibrillations. Patients in the lowest tertile (≤1.88) showed the worse prognosis with higher incidence of follow-up events compared to median tertile (1.89–2.29) and highest tertile (≥2.30) (see figure). At multivariable analysis, NYHA functional class (HR: 2.234, 95% CI: 1.398–3.517, p=0.001), presence of LVOTO at rest (HR: 2.958, 95% CI: 1.074–3.570, p=0.028) and lowest tertile of CFVR (HR: 2.144, 95% CI: 1.126–4.081, p=0.011) were the independent predictors of follow-up events.

Conclusions

In HCM patients, reduction in CFVR is associated to a clearly worse outcome. The spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale.

Figure 1

Funding Acknowledgement

Type of funding source: None
Quantitative analysis of mitral annulus morphology in aortic stenosis using real time 3-dimentional transesophageal echocardiography
Authors: Suzuki W , Nakano Y , Ohashi H , Ando H , Waseda K , Takashima H , Uchida Y , Amano T
Published: November 2020

Background

Normal mitral annulus morphology is known to be saddle shape. There are a few reports regarding the relationship between flattening of the mitral annular saddle shape and mitral regurgitation. However, the relationship between aortic stenosis (AS) and mitral annulus morphology is unknown.

Purpose

To assess the impact of AS on mitral annular saddle shape using 3-dimentional transesophageal echocardiography.

Methods

A total of consecutive 83 subjects including 44 patients with severe AS (AS group) and 39 patients without AS (control group), who underwent real-time 3-dimentional transesophageal echocardiography of the mitral valve, were enrolled. The 3-dimentional geometry of the mitral annulus apparatus was evaluated by the parameters analyzed using dedicated quantification software such as anteroposterior diameter (APD), commissural width (CW), annular height (AH), mitral annulus (MA) area and annular height to commissural width ratio (AHCWR) as shown in Figure. We assessed the impact of severe AS on AHCWR, which is the key parameter showing flattening of the mitral annular saddle shape. These parameters were adjusted by body surface area (BSA). Exclusion criteria included left ventricular ejection fraction <50%, the presence of aortic regurgitation, mitral valve disease, pericardial or congenital diseases, endocarditis, cardiomyopathy, prior myocardial infarction, and paroxysmal or persistent atrial fibrillation.

Results

Comparisons of mitral valve geometry between AS group and control group are summarized in Table. AH/BSA and AHCWR were significantly lower in AS group compared with control group. Multiple linear regression analysis revealed severe AS to be a significant and independent predictor of lowering AHCWR (β=−0.39, t=−4.04, p<0.001) (adjusted with MA area, selected by stepwise analysis).

Conclusions

Severe AS might contribute to flattening of the mitral annular saddle shape, lead to the mitral annular structural remodeling. Assessment of the mitral annulus morphology might help evaluating severe AS.

Mitral annulus 3-dimensional geometry

Funding Acknowledgement

Type of funding source: None
Risk stratification on echocardiography and outcome in ischaemic mitral regurgitation
Authors: Sharma H , Radhakrishnan A , Brown S , May J , Zia N , Joshi R , Nightingale P , Ludman P.F , Townend J.N , Doshi S.N , Khan S.Q , Zaphiriou A , George S , Nadir A , Steeds R.P
Published: November 2020

Background

Ischaemic mitral regurgitation (IMR) confers a poor prognosis. Transcatheter intervention may improve survival but benefit is likely to depend on severity of IMR relative to LV remodelling following myocardial infarction (MI). In theory, those with “discordant” IMR (significant regurgitant volume without severe LV dilatation or impairment), are expected to benefit most from mitral intervention. While subcategorization may help to inform treatment, there are no data on post-MI patients in this respect.

Purpose

To determine the incidence of discordant & concordant IMR categorised on echocardiography post-MI and impact on outcomes.

Methods

1000 consecutive patients admitted to our hospital with myocardial infarction who underwent coronary angioplasty were included. Early inpatient TTE was performed by accredited echocardiographers using standard multiparametric quantification.

Using TTE parameters, 4 subgroups were identified (figure) according to the degree of MR relative to LV remodelling. Thresholds were based on European guidelines (± 2SD from normal) and median value among survivors for vena contracta (VC):

– LVEF: 52% (♂), 54% (♀)

– Indexed LV end diastolic volume (LVEDVi): 74ml/m2 (♂), 61ml/m2 (♀)

– Effective regurgitant orifice area (EROA) ≥0.2cm2

– Regurgitant volume (RVol) ≥30ml

– VC ≥0.5cm

Results

MR was seen in 294/1000 patients (29.4%) with a severity of mild (76%), moderate (21%) and severe (3%). Concordant and discordant IMR were each seen in 16/294 (5%) of IMR patients post-MI.

After a mean follow up of 3.2 years, IMR patients had a 3% rate of heart failure (HF) within 1 year and 19% mortality. Non-survivors had significantly worse IMR (PISA 0.65±0.25cm vs 0.54±0.19cm; p=0.033; VC 0.63±0.25cm vs 0.49±0.18cm; p=0.014), worse LV function (LVEF 44±17% vs 51±13%; p<0.001), larger LV (LVEDVi 67±23ml/m2 vs 60±22ml/m2; p=0.032) and larger indexed LA volume (LAVi) (44±22ml vs 35±15ml; p<0.001). Those with concordant IMR had the worst survival (50%) although almost 1 in 5 of those with discordant MR died within the follow up period (19%). Using multivariable Cox regression, significant predictors of mortality included LVEF (p<0.001; HR 0.96, 0.94–0.98) and LAVi (p<0.001; HR 1.02, 1.01–1.03) but not LVEDVi.

Conclusion

1) Significant predictors of mortality in IMR include LA dilatation and decline in LVEF, but not LV dilatation.

2) Although discordant severe IMR is uncommon following MI, mortality if left untreated remains high. Attention should be paid to early selection of this cohort for intervention.

Funding Acknowledgement

Type of funding source: None
One-year echocardiographic outcomes of transcatheter aortic valve implantation with or without predilatation of the aortic valve: insights from the multicenter, randomized DIRECT trial
Authors: Karmpalioti M , Benetos G , Drakopoulou M , Xanthopoulou M , Stathogiannis K , Latsios G , Synetos A , Kalantzis C , Voudris V , Kosmas E , Mastrokostopoulos A , Katsimagklis G , Danenberg H , Tousoulis D , Toutouzas K
Published: November 2020

Introduction

Transcatheter aortic valve implantation (TAVI) has become the standard of care for high-risk and inoperable surgical patients and a valid alternative in intermediate-risk patients with severe aortic stenosis.The DIRECT trial (Predilatation in Transcatheter Aortic Valve Implantation Trial) was a multicenter, randomized, clinical trial designed to evaluate the safety and efficacy of TAVI with or without balloon aortic valvuloplasty (BAV) in patients with symptomatic, severe aortic valve stenosis.

Purpose

To compare the one year echocardiographic findings among patients, who underwent TAVI using a self-expanding valve with or without BAV.

Methods

A total of 171 patients with severe aortic stenosis were randomly assigned at 4 tertiary centers to undergo TAVI with the use of self-expanding prostheses with (pre-BAV) or without pre-dilatation (no-BAV). Follow up transthoracic echocardiography was performed 1 year after TAVI.

Results

Of 171 patients, 86 patients were randomized to pre-BAV group and 85 to no-BAV group. One year echocardiographic follow up was available in 146 patients. In one year follow up there was no significant difference between pre-BAV and no-BAV group in aortic valve area (1.84±0.39cm2 vs. 1.85±0.44cm2, p=0.79), peak aortic valve gradient (15.95±9.97 mmHg vs. 14.51±6.60 mmHg, p=0.35), mean aortic valve gradient (8.37±5.01 mmHg vs. 7.99±4.04 mmHg, p=0.64), aortic valve peak velocity (1.90±0.51 m/s vs. 1.80±0.42m/s, p=0.24), ejection fraction (54.19±8.36% vs. 53.19±9.58%, p=0.52) and pulmonary artery systolic pressure (41.86±14.34 mmHg vs. 40.71±12.40 mmHg, p=0.64). The incidence of moderate or severe paravalvular regurgitation (PVL) in 1 year follow up was 6.2% without significant difference between the 2 study groups (5.7% in the no-BAV group vs. 6.6% in the pre-BAV group, p=0.83).

Conclusions

Direct transcatheter aortic valve implantation has no impact on one-year prosthesis function and PVL in patients undergoing TAVI with self-expanding valve

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Medtronic
Beyond effective regurgitant orifice in quantitative assessment of tricuspid regurgitation: impact on clinical outcomes
Authors: Hinojar Baydes R , De Angelis V , Gonzalez-Gomez A , Garcia-Martin A , Monteagudo J.M , Pascual M , Lorente A , Jimenez-Nacher J.J , Zamorano J.L , Fernandez-Golfin C
Published: November 2020

Background

Quantification in tricuspid regurgitation has been poorly investigated. Recommended methods and thresholds are directly translated from mitral regurgitation; however, the anatomy, hemodynamics, and regurgitant orifice geometry are different in TR. Effective regurgitant orifice (ERO) calculation may be incorrect in very severe TR when right atrial and ventricular pressures could get equalized resulting in typically very low TR velocities.

Purpose

Our aim was to compare the prognostic value of different parameters for the evaluation of the tricuspid regurgitation (TR).

Methods

Consecutive patients with significant TR (≥ moderate echocardiographic grade) evaluated in the Heart Valve Clinic were included. TR severity was evaluated by TR radius, TR flow rate, ERO and TR regurgitant volume by PISA method and biplane vena contracta (VC) width using EPIQ system. End-point included cardiovascular mortality, tricuspid valve surgery or heart failure.

Results

A total of 100 patients were included (mean age: 76±10 years, 65% females, 86% functional TR, 84% in NYHA I/II). During a mean follow up of 24±10 months 36% of the patients reached the combined end-point. Patients with events showed more severe TR independently of the parameter applied (table). In univariate analysis, TR radius, TR flow rate, ERO and TR regurgitant volume were predictors of the combined endpoint (p<0.05 for all). Among all parameters, TR flow rate was the strongest and independent predictor of outcomes in multivariate and ROC analysis (HR per 1 ml/seg 1.02 [1.003–1.026], p=0.01). A value of TR flow rate of 109 ml/sec reached the best accuracy to predicted poor outcomes (p<0.01).

Conclusion

Among different parameters to graduate TR severity, TR flow rate was the strongest predictor of outcomes. Since it does not include the TR velocity in the calculation, its incremental benefit may be related to very severe cases of TR. In this scenario, right atrial and ventricular pressures are equalized and TR velocity calculation is not longer possible. New grading schemes for TR may include this parameter in the classification.

Funding Acknowledgement

Type of funding source: None
Usefulness of non-invasive myocardial work to predict left ventricular recovery and acute complications after acute anterior myocardial infarction treated by primary angioplasty
Authors: Meimoun P , Abdani S , Gannem M , Stracchi V , Elmkies F , Boulanger J , Zemir H , Clerc J
Published: November 2020

Background

Predicting left ventricular (LV) recovery after acute ST-elevation myocardial infarction (STEMI) is challenging and of prognostic importance.

Objective

To evaluate the usefulness of non-invasive myocardial work (MW), a new index of global and regional myocardial performance, to predict LV recovery and in-hospital complications after STEMI.

Methods

Ninety-three consecutive patients with anterior STEMI (mean age, 59±12 years) treated by primary angioplasty underwent transthoracic echocardiography (TTE) within 24–48 hours after angioplasty and a median of 92 days at follow-up. MW is derived from the non-invasive strain-pressure loop obtained from the 2D strain data, integrating in its calculation the non-invasive brachial arterial pressure. Segmental LV recovery was defined as a normalization of segmental wall motion abnormalities of the affected segments and global recovery as an absolute improvement of left ventricular ejection fraction (LVEF) greater than 5% in patients with baseline LVEF <50%. In-hospital complications were defined as a composite of death, reinfarction, heart failure, and LV apical thrombus.

Results

1642 segments were studied and MW was impaired in infarct segments, more severely in no recovery versus recovery segments (MW index, constructive MW, MW efficiency, all, p<0.01). Furthermore, global MW was significantly correlated to acute and follow-up LVEF and global longitudinal strain (GLS) (all, p<0.01). Constructive MW was the best indice to predict segmental (p<0.01 versus MW index, MW efficiency, and wasted work), and global recovery (p<0.05 versus GLS) with an independent association (all, p<0.01). Moreover, global constructive MW was independently associated to in-hospital complications which occurred in 18 patients (p<0.01).

Conclusion

In patients with anterior STEMI treated by primary angioplasty, acute constructive MW is an independent predictor of segmental and global LV recovery, as well as in-hospital complications.

Funding Acknowledgement

Type of funding source: None
Myocardial work analysis in screening of familial dilated cardiomyopathy
Authors: Triantafyllou M , Monteiro R , Protonotarios A , Gossios T , Elliott P , Lloyd G , Savvatis K
Published: November 2020

Introduction

Early detection of affected family relatives of patients with dilated cardiomyopathy (DCM) is essential in order to guide follow up, outcomes and initiate early treatment. Myocardial work analysis is a novel method which integrated strain imaging and blood pressure and has the potential to identify patients with subclinical disease.

Purpose

We analysed myocardial work in family relatives of DCM patients with positive genotype but negative phenotype in order to identify whether myocardial work can identify early changes.

Methods

Seventy-four family relatives of DCM patients attending for screening were examined. All individuals were asymptomatic with either positive (45/74, G+) or negative (29/74, G-) genotype and no echocardiographic evidence of left ventricular dilatation or systolic impairment. Non-invasive myocardial work analysis using two-dimensional (2D) speckle tracking echocardiography was analysed. Global longitudinal strain (GLS) was measured by the same vendor specific software used for myocardial work analysis. Left ventricular (LV) ejection fraction (EF) was measured with the Simpson's biplane method. The peak systolic arm cuff blood pressure (BP) measurement at the time of echocardiography was used for the myocardial work study.

Results

In total we included 74 individuals (37±15 years old, 50.7% women) with mean systolic and diastolic BP of 121.3±14 and 73.2±10 mmHg respectively, mean EF was 58±5% and mean GLS at 18.4±2.5%.

G+ individuals had pathogenic and very likely pathogenic mutations in 8 different genes (TTN, BAG3, DSP, FLNC, LMNA, DMD, RBM20, TPM1). There was no difference in age, systemic hypertension, diabetes or medical treatment between the 2 groups.

No significant difference was found among G+ and G- individuals in mean systolic and diastolic BP (121.2±14.7 vs 121.2±15.2 mmHg), mean EF (57.3±5 vs 59.1±4%), GLS (−18.2±1.5 vs −18.6±2.9%), mean global work index (1818±403 vs 1928±295 mmHg%) and global constructive work (2192±464 vs 2260±318 mmHg%).

However, we found significant reduction of the global work efficiency (GWE) with a GWE of 94.4±2.7% in the G+ versus 95.9±1.6% in the G- individuals (p 0.02). Moreover, the global wasted work (GWW) was increased in the G+ with a GWW of 111±58 mmHg% versus 82±41 mmHg% in the G- individuals (p 0.03).

Conclusion

DCM gene carriers show, early on, decreased myocardial work efficiency and increased wasted work compared to unaffected family members, which appears to be earlier than other parameters such as EF and GLS. Myocardial work analysis could potentially recognize individuals showing early cardiac involvement and guide closer follow up and early initiation of treatment.

Funding Acknowledgement

Type of funding source: None
Relationship between cardiac structure and function and atrial fibrillation related hospitalizations following catheter ablation
Authors: Olsen F.J , Darkner S , Chen X , Pehrson S , Johannessen A , Hansen J , Gislason G , Svendsen J.H , Biering-Sorensen T
Published: November 2020

Background

Even though catheter ablation (CA) is an effective treatment for atrial fibrillation (AF), AF-related hospitalizations and cardioversions are common following this procedure.

Purpose

To investigate whether echocardiographic measures of left atrial (LA) function could predict AF-related hospitalizations and cardioversions.

Methods

This was a substudy of a trial that randomized patients to amiodarone vs place to reduce AF recurrence following CA. Transthoracic echocardiography was performed prior to CA and included assessment of: end-systolic and end-diastolic LA volumes, emptying fraction (LAEF), atrial strain, and global longitudinal strain (GLS). Poisson regression was used to assess predictive value for AF-related hospitalizations and cardioversions. Multivariable adjustments were made for: age, gender, ejection fraction, AF burden, AF subtype, dyspnea, and class 1c antiarrhythmics.

Results

Of the 212 patients, 80 were hospitalized for AF (206 times), and 77 were cardioverted (192 times) within the 6 months follow-up period. Mean age was 60 years, 83% were men, and mean LVEF was 50%. In univariable analyses, LA volumes, LAEF and GLS were predictors of the outcomes but did not remain significant predictors after multivariable adjustments. During echocardiography 162 patients were in sinus rhythm and 50 had AF rhythm. Rhythm during the echocardiogram modified the association between GLS and outcomes (p for interaction <0.05 for both endpoints), such that GLS predicted both AF-related hospitalizations and cardioversions in patients with sinus rhythm but not AF during the echocardiogram (figure).

Conclusion

Global longitudinal strain predicts AF-related hospitalizations and cardioversions after CA, but only in patients presenting in sinus rhythm during the echocardiogram. Patients presenting with impaired global longitudinal strain should be considered high-risk patients following CA who may benefit from close follow-up.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Danish Heart Foundation
Mechanical Dispersion as a powerful echocardiographic predictor of outcomes after Myocardial Infarction
Authors: De Sousa Bispo J.P , Azevedo P , Freitas P , Marques N , Reis C , Horta E , Trabulo M , Abecasis J , Canada M , Ribeiras R , Andrade M.J
Published: November 2020

Introduction

Several studies have addressed the importance of transthoracic echocardiography (TTE) in risk prediction of subsequent adverse events after ST elevation myocardial infarction (STEMI). While several traditional echo parameters have a well-established prognostic value, data derived from 2D-Speckle Tracking Echocardiography (2DSTE) needs further investigation.

Objectives

To determine if 2DSTE parameters provide additional information beyond conventional echocardiography to predict long-term adverse outcomes in patients admitted with STEMI

Methods

Retrospective, single-center study, that included all patients without previous cardiovascular events admitted with STEMI (who underwent primary coronary angioplasty) between 2015 and 2017. Patients with poor acoustic windows, severe valvular disease, irregular heart rhythm, and those who died during hospital stay were excluded. We reviewed all pre-discharge TTE to assess conventional parameters of LV systolic and diastolic function and data obtained by 2DSTE: global longitudinal strain (GLS) and peak strain dispersion (PSD), an index that is the standard deviation from time to peak strain of all segments over the entire cardiac cycle. Demographic and clinical data was obtained through electronic hospital records. Minimum follow-up was 2 years. The primary endpoint was a composite of all-cause mortality and cardiovascular re-admission at follow-up. Survival analysis was used to determine independent predictors of the primary endpoint.

Results

377 patients were included, mean age 62±13 years, 72% male. Mean LVEF was 50±10% with 19% of patients having LVEF <40%. Mean indexed left atrium volume (LAVi) was 33±10 ml/m2, mean GLS was −14±4%, and PSD was 60±22 msec. Average follow-up was 36±11 months, with a combined endpoint of mortality and hospitalization of 27% (n=102)

Univariate analysis of echocardiographic variables revealed an association between heart rate, LVEF, indexed LV end-systolic volume, indexed stroke volume, LAVi, GLS and PSD with the endpoint. However, on multivariate analysis only LAVi [HR 1.030 (95% CI 1.009 - 1.051), p-value = 0.005] and PSD [HR 1.011 (95% CI 1.002 - 1.020), p-value = 0.012] remained independent predictors of the primary endpoint.

We determined that a PSD value higher than 52 msec has a sensitivity of 76% and a negative predictive value of 83% for mortality and hospitalization, and that this cut-off point discriminates patients at a higher risk of events in Kaplan-Meier Survival analysis with a Log-Rank p-value=0.001.

Conclusion

PSD derived by longitudinal strain analysis is a promising prognostic predictor after STEMI. PSD outperformed conventional echocardiographic parameters in the risk stratification of STEMI patients at discharge.

Kaplan-Meier Survival Curves

Funding Acknowledgement

Type of funding source: None
Impact of rhythm in non-valvular atrial fibrillation on four cardiac chamber deformation imaging
Authors: Philabout P , Soulat-Dufour L , Benhamou-Tarallo I , Lang S , Ederhy S , Ancedy Y , Adavane-Scheuble S , Chauvet-Droit M , Nhan P , Jean M , Ben Said R , Boccara F , Addetia K , Lang R , Cohen A
Published: November 2020

Background

Few studies have assessed the evolution of cardiac chambers deformation imaging in patients with atrial fibrillation (AF) according to cardiac rhythm outcome.

Purpose

To evaluate cardiac chamber deformation imaging in patients admitted for AF and the evolution at 6-month follow-up (M6).

Methods

In forty-one consecutive patients hospitalised for AF two-dimensional transthoracic echocardiography was performed at admission (M0) and after six months (M6) of follow up. In addition to the usual parameters of chamber size and function, chamber deformation imaging was obtained including global left atrium (LA) and right atrium (RA) reservoir strain, global left ventricular (LV) and right ventricular (RV) free wall longitudinal strain. Patients were divided into three groups according to their cardiac rhythm at M0 and M6: AF at M0 and sinus rhythm (SR) at M6 (AF-SR) (n=23), AF at M0 and AF at M6 (AF-AF) (n=11), SR at M0 (spontaneous conversion before the first echocardiography exam) and SR in M6 (SR-SR) (n=7)

Results

In comparison with SR patients (n=7), at M0, AF patients (n=34)) had lower global LA reservoir strain (+5.2 (+0.4 to 12.8) versus +33.2 (+27.0 to +51.5)%; p<0.001), lower global RA reservoir strain (+8.6 (−5.4 to 11.6) versus +24.3 (+12.3 to +44.9)%; p<0.001), lower global LV longitudinal strain (respectively −12.8 (−15.2 to −10.4) versus −19.1 (−21.8 to −18.3)%; p<0.001) and lower global RV longitudinal strain (respectively −14.2 (−17.3 to −10.7) versus −23.8 (−31.1 to −16.2)%; p=0.001). When compared with the AF-SR group at M0 the AF-AF group had no significant differences with regard to global LA and RA reservoir strain, global LV and RV longitudinal strain (Table). Between M0 and M6 there was a significant improvement in global longitudinal strain of the four chambers in the AF-SR group whereas no improvements were noted in the AF-AF and SR-SR group (Figure).

Conclusion

Initial atrial and ventricular deformations were not associated with rhythm outcome at six-month follow up in AF. The improvement in strain in all four chambers strain suggests global reverse remodelling all cardiac cavities with the restoration of sinus rhythm.

Evolution of strain between M0 and M6

Funding Acknowledgement

Type of funding source: None
Early change in left atrial and left ventricular strain predicts sinus rhythm maintenance after cardioversion
Authors: Kupczynska K , Miskowiec D , Michalski B , Szyda L , Wierzbowska-Drabik K , Wejner-Mik P , Lipiec P , Kasprzak J.D
Published: November 2020

Background

Atrial fibrillation (AF) impairs mechanical function of the heart, especially atria and restoration of sinus rhythm (SR) leads to improvement of mechanics. The predicting role of changes in strain parameters for AF recurrence is not established yet.

Purpose

To analyse changes in left atrial (LA) and left ventricular (LV) mechanical function after conversion to SR and their prognostic values for AF recurrence during 24 months follow-up.

Methods

Prospective study involved 59 patients after successful electrical cardioversion (EC) because of nonvalvular AF (mean age 65±4 years, 47% female). Speckle tracking analysis (STE) was applied to calculate longitudinal strain of LV and LA before EC and within 24 hours after restoration of SR and additionally total left heart strain (TS) defined as a sum of absolute peak LV and LA strain. We calculated change in strain between AF and SR analyses expressed as delta (Δ). During follow-up we noticed AF recurrence in 42 (71%) patients, most of them (93%) during 1st year after EC. Median time of AF recurrence was 3 months.

Results

We noticed significant immediate post-EC improvement in peak LA longitudinal strain (PALS) and LV global longitudinal strain (LVGLS) (table). Unlike CHA2DS2-VASc score, strain parameters were predictors of AF recurrence. Every 1% increment in ΔLVGLS was related with 13% increase in AF recurrence risk (p=0.02) and every 1% increment in ΔPALS and ΔTS were related with 9% decrease in AF recurrence risk (p=0.007 and p=0.0014, respectively). Multivariate analysis revealed ΔTS as a strongest predictor with 9% decrease in AF risk per every 1% increment. The criterion of ΔTS ≤7.5% allows to predict AF recurrence with 81% sensitivity and 63% specificity.

Conclusions

Speckle tracking measurements are able to detect early mechanical changes in LA even within 24 hours of SR and these absolute changes in LVGLS as well as PALS can predict AF recurrence, with optimal stratification by novel parameter - TS.

Funding Acknowledgement

Type of funding source: None
Differences in valve morphology between patients with bicuspid and tricuspid aortic valve
Authors: Aviv Y , Nassar M , Perlman G , Arow Z , Lessick J , Danenberg H , Vaknin-Assa H , Finkelstein A , Kornowski R , Hamdan A
Published: November 2020

Background

Bicuspid aortic valve (BAV) patients represent a significant minority of severe aortic stenosis (AS) patients undergoing transcutaneous aortic valve implantation (TAVI). These patients demonstrate anatomic differences compared to tricuspid aortic valve (TAV). Ethnicity is associated with different valve morphologies characterized by Siever's classification.

Purpose

We aim to evaluated the prevalence of BAV subtypes and the differences in valve morphology and aortic root dimensions between BAV and TAV in patients undergoing computed tomography (CT) before TAVI.

Methods

In five Israeli medical centers, 131 patients with BAV and 674 patients with TAV underwent CT angiography. BAV morphology was defined according to the number of commissures and raphe, following Siever's classification. Aortic root dimensions were measured at the level of the aortic annulus, sinus of Valsalva (SOV), and sino-tubular junction (STJ). Finally, Agatston score unit (AU) for valve calcification was evaluated.

Results

Type 0 accounted for 27% (36/131), Type IA for 63% (82/131), Type IC for 9% (12/131), and Type 2 for 1% (1/131). Calcium score in BAV patients was significantly higher compared to TAV patients, 4000±1897 vs. 2152±1216 AU; respectively (P<0.001). Distance from the annulus to the left main coronary artery was greater in BAV patients compared to TAV (13.8±3.6 mm vs. 12.8±2.8 mm; respectively, P<0.001), similar distance from annulus to right coronary artery was observed in BAV and TAV patients (16.7±3.7 mm vs. 15±3 mm; respectively, P<0.001). Aortic annulus perimeter was greater in BAV than TAV patients (79.3±11mm vs. 73±8.7mm, respectively, P<0.001), as well as SOV perimeter (35.7±4.5mm vs. 32±3.7mm, respectively, P<0.001), and STJ perimeter (32.3±5mm vs. 27±3.3 mm; respectively, P<0.001).

Conclusion

In Israel, AS patients showed more frequently type 1A BAV. BAV patients have larger aortic root dimensions and higher calcium burden than TAV patients.

Funding Acknowledgement

Type of funding source: None