bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards accurate numerical fluid dynamics of pump-turbine runners in deep partial load operation
Authors: Zorn M , Khalfaoui K , Riedelbauch S
Published: October 2022

The operation of pumped storage power plants at off-design conditions requires an understanding of the flow field and the resulting damage to ensure a safe and economic operation. Within this study, CFD simulations are carried out for an existing pump-turbine at deep part load operation to enable calculating the damage in later structural analyses. Furthermore, this study includes the comparison between the SST and SBES turbulence model at different mesh sizes. The simulation results are compared with model test data regarding head, torque and pressure fluctuations at a bottom ring and draft tube cone sensor. Whereas all simulation setups are within a reasonable range to the available model test data, the pressure fluctuations on the runner blades as well as the resolved vortices within the runner blade channels show a qualitative difference between both models. The SBES turbulence model resolves more vortices and thus different pressure fluctuations. Subsequent structural analyses show higher accuracy of the SBES turbulence model compared with the SST model. A mesh refinement from 25 million nodes to 80 million nodes with the SBES model reveals a better resolution of vortices, but only local differences in pressure fluctuations.
Procedure to minimize rotor vibrations from flow-induced excitations in Kaplan turbines
Authors: Jonsson P P , Nässelqvist M L , Mulu B G , Högström C M
Published: October 2022

The flow pattern in the draft tube is commonly considered when investigating rotor vibration problems, especially for Francis turbines. However, phenomenon in the vaneless space for Kaplan turbines have been shown to induce rotor vibrations when operating in non-standard conditions such as speed no load (SNL). These flow disturbances develop in the vaneless space at small guide vane openings and high swirls. Depending on the number of flow disturbances and runner blades they can excite transversal, axial or torsional vibrations. In the case of transversal excitation they can in some cases cause resonance problems if the frequency is close to a natural frequency of the rotating structure. Recently it was observed that the excitation causes severe resonance in the rotating structure on a refurbished turbine when operated at SNL.

The present paper presents frequency analysis of the flow-induced excitations coupled to the shaft vibrations on an old and a refurbished Kaplan turbine. To investigate the causes of the resonance problem, measurements have been performed on both the model and prototype turbine and on a twin unit with the old runner design. The measurements on the prototypes consist of pressure, shaft bending moment, and vibrations. Pressure and radial forces were measured on the model.

The result shows the dependence of the runner blade opening on the transversal excitation and the frequency of the flow disturbances. The rotordynamic analysis showed the same phenomena with forward and backward precession. The results agree well between the model and prototype when measured data are normalized by the runner rotational frequency. It is proposed, when refurbishing a unit, to use measured pressures, shaft bending moment and vibrations on the prototype before the refurbishment and the new model turbine to identify critical excitation frequencies for the new prototype turbine, i.e., use the information from the tests to set rotordynamic requirements for the new prototype unit.
Hybridization in Kaplan turbines. Wear and tear assessment
Authors: Valentín David , Presas Alexandre , Egusquiza Mònica , Valero Carme
Published: October 2022

In the current energy market, hydraulic turbines are increasingly demanded to work in Frequency containment reserve (FCR) mode to compensate the constant frequency fluctuations in the electrical grid. To do so, hydraulic turbines change their generating power continuously which implies to regulate the flow rate. Kaplan turbines are double regulated machines that change the position of both guide vanes and runner blades to regulate the flow rate maximizing their efficiency. Therefore, guide vanes and runner blades are continuously moving when they provide FCR, leading to high wear and tear of the regulation system components.

Within the frame of the European project XFLEX Hydro, a new technology to reduce the wear and tear of the regulation system in FRC have been implemented. This technology consists in the hybridization of the unit with a battery system. In that way, the battery is the one in charge of providing part of the power fluctuations to the grid, reducing the movements of guide vanes and runner blades of the turbine. The battery system was successfully installed in August 2021 in one unit of the Vogelgrun powerplant, in France. Since that moment, the unit has been working in hybrid mode.

A monitoring system was installed in the power plant in two different units, the one hybridized and another without hybrid system. Several sensors were installed and different parameters were measured simultaneously to calculate the wear and tear of the different components. In this paper, a comparison between the hybrid mode and the standard mode (non-hybrid) is performed in terms of mileage and wear and tear of the guide vanes and runner blades servomotors.
Pushing the envelope of ancillary services with variable speed technology
Authors: Dreyer M , Nicolet C , Alligné S , Seydoux M , Jung A , Cordeiro D
Published: October 2022

Hydropower is the backbone of energy transition thanks to its operational flexibility and ability to provide ancillary services. These grid support capabilities are called upon to play a major role to maintain the grid vulnerability at acceptable levels in view of the increasing penetration of stochastic and intermittent renewable energies. In this context, variable speed reversible pump-turbine technology is a key asset as it can extend the head operating range of a powerplant, enable power network control in pump mode and further increase the flexibility services to the electrical grid. Furthermore, by taking advantage of the so-called flywheel effect, variable speed enables the fast active power injection/absorption in pumping and generating mode. The additional degree of freedom offered by the variable speed opens the door to different control strategies for the hydroelectric plant, as the converter can be used for speed or power control. This can be exploited to maximize either the efficiency or the power reserve dedicated to grid support. In this paper, the strategies to maximize the ancillary service of Frades 2 pumped storage power plant (PSPP) are investigated. The plant features two high-head single-stage reversible variable speed units, coupled with 420 MVA doubly-fed induction motor-generators (DFIM). Using a 1D numerical model to simulate the power plant behavior, it is explored to which extent Frades 2 can deliver frequency containment reserve (FCR) power, while complying with the ENTSO grid code, and speed deviation constrains inherent to DFIM. By choosing a strategy which fully exploits the flywheel effect, it is established that the FCR power band can be equal to the whole operating range of the power plant. Moreover, the fast frequency response capacity (FFR) is also evaluated. It is found that by maximizing the energy stored in the rotating masses, each unit of Frades 2 can deliver up to 110 MW of active power in 1.3 seconds.
Social Change, Gender Stratification and the Sex Gap of Homicide Victimization in 76 Countries, 1975–2017
Authors: Lu Yunmei , Santos Mateus R , Zhang Zhe
Published: October 2022

This study examines the longitudinal change in the sex gap of homicide victimization in 76 countries between 1975 and 2017. We compiled a cross-national dataset with homicide victimization data from WHO and structural measures from multiple databases. Our findings reveal that countries with low homicide rates and rapid homicide decline are more likely to have narrowing sex gaps, and that the narrowing gaps are mainly driven by male homicide decline. Different from the prior literature, we find null associations between most measures of gender stratification and the sex gap. Instead, results reveal that aging population is associated with a narrowing sex gap. Implications are discussed, including the specific effects of the study period and the shifting dynamics of homicide trends.
The politics of representation in Squid Game and the promise and peril of its transnational reception
Authors: Oh David C
Published: October 2022

This article introduces the special forum on representations and transnational reception of Squid Game. The purpose of the forum is to draw together two groups of scholars into dialogue. The first are Korea experts in communication and cognate fields, who consider the politics of representation in the show against the backdrop of neoliberal capitalist precarity, and the second are scholars of audience reception, who point to the ways Squid Game’s overseas reception is marked by power—hegemonic power that reifies dominant ideological meanings at the site of reception and resistive power for marginalized groups at the site of reception, who produce Squid Game-related paratexts to imagine inter-racial, affective connection.
The Elements of International Legal Positivism
Authors: Hovell Devika
Published: October 2022

This article contains a plea for continuing attention to the elements of international legal positivism. Using the language of ‘elements’ deliberately plays on the positivist tendency to describe the legal discipline as a legal science. Yet law’s elements differ in important ways from the usual objects of scientific inquiry. Law’s method does not seek to address the structure and behaviour of the physical world, but that of a particular society with its own political polarities, structure and functions. The fact that international law inherits its positivist method from the domestic legal context therefore presents complications. While the adoption of positivism as international law’s predominant legal method was animated in part by a desire to provide international law with the imprimatur it needs to claim credibility as a legal system, it has also served as an impediment to international law’s development in a distinctive fashion from domestic law. International law’s attachment to the positivist method has at times extended to an attachment to certain presuppositions more closely associated with the development of the modern European state. This article takes the position that it is important to engage with international legal positivism on its own terms. Part I traces the lineage of three important traditions of international legal positivism (‘social thesis’ positivism, ‘system-based’ positivism and ‘teleological’ positivism) highlighting their different emphases and in doing so identifying key elements. Part II interrogates certain presuppositions sometimes associated with these traditions and considers whether it is appropriate to rethink or re-engineer these aspects in their application to the international legal system. While positivism is sometimes associated with ‘purifying’ law as a discipline, the article takes the position that the positivist method can only endure if complemented by a rich legal, political and social discourse focused on understanding its relationship to the elements of the international legal system, in particular, international law’s community, authority and functions.
Mortality in Patients with Inflammatory Bowel Disease: Results from 30 Years of Follow-up in a Norwegian Inception Cohort (the IBSEN study)
Authors: Follin-Arbelet Benoit , Cvancarova Småstuen Milada , Hovde Øistein , Jelsness-Jørgensen Lars-Petter , Moum Bjørn
Published: October 2022

Background and Aims

Patients with longstanding inflammatory bowel disease [IBD] may be at an increased risk of death compared to the general population, especially elderly patients. The Inflammatory Bowel South-Eastern Norway [IBSEN] study has previously detected a small but not statistically significant increase in mortality 20 years after diagnosis. The aim of this study was to evaluate the overall and cause-specific mortality at 30 years of follow-up.

Methods

The IBSEN cohort included 519 incident patients with ulcerative colitis [UC] and 237 patients with Crohn’s disease [CD] between 1990 and 1993, each matched with five controls. Death certificate data were obtained from the Norwegian Cause of Death Registry. The underlying causes of death were categorized into five groups: all cancers, gastrointestinal cancers, cardiovascular diseases, infections and all other causes. Hazard ratios [HRs] were modelled using Cox regression.

Results

There was no statistically significant difference in the overall mortality rates. However, in patients with CD, male sex (HR = 1.65 [95% CI: 1.04–2.62]), onset after 40 years of age (HR = 1.72 [1.19–2.48]), colonic disease (HR = 1.57 [1.05–2.35]) and penetrating behaviour (HR = 3.3 [1.41–7.76]) were clinical factors associated with an increased mortality. IBD patients were at a higher risk of death due to cardiovascular disease: HR = 1.51 [1.10–2.08] for UC and 2.04 [1.11–3.77] for CD. When taking into account both the underlying and the immediate cause of death, infection was more frequent in patients with IBD.

Conclusions

Overall, all-cause mortality rates were similar between patients with IBD and controls. However, clinicians should remain alert to cardiovascular diseases and infections, particularly in specific subgroups of CD patients.
Cardiovascular magnetic resonance in light-chain amyloidosis to guide treatment
Authors: Martinez-Naharro Ana , Patel Rishi , Kotecha Tushar , Karia Nina , Ioannou Adam , Petrie Aviva , Chacko Liza A , Razvi Yousuf , Ravichandran Sriram , Brown James , Law Steven , Quarta Cristina , Mahmood Shameem , Wisniowski Brendan , Pica Silvia , Sachchithanantham Sajitha , Lachmann Helen J , Moon James C , Knight Daniel S , Whelan Carol , Venneri Lucia , Xue Hui , Kellman Peter , Gillmore Julian D , Hawkins Philip N , Wechalekar Ashutosh D , Fontana Marianna
Published: October 2022

Aims

To assess the ability of cardiovascular magnetic resonance (CMR) to (i) measure changes in response to chemotherapy; (ii) assess the correlation between haematological response and changes in extracellular volume (ECV); and (iii) assess the association between changes in ECV and prognosis over and above existing predictors.

Methods and results

In total, 176 patients with cardiac AL amyloidosis were assessed using serial N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiography, free light chains and CMR with T1 and ECV mapping at diagnosis and subsequently 6, 12, and 24 months after starting chemotherapy. Haematological response was graded as complete response (CR), very good partial response (VGPR), partial response (PR), or no response (NR). CMR response was graded by changes in ECV as progression (≥0.05 increase), stable (<0.05 change), or regression (≥0.05 decrease). At 6 months, CMR regression was observed in 3% (all CR/VGPR) and CMR progression in 32% (61% in PR/NR; 39% CR/VGPR). After 1 year, 22% had regression (all CR/VGPR), and 22% had progression (63% in PR/NR; 37% CR/VGPR). At 2 years, 38% had regression (all CR/VGPR), and 14% had progression (80% in PR/NR; 20% CR/VGPR). Thirty-six (25%) patients died during follow-up (40 ± 15 months); CMR response at 6 months predicted death (progression hazard ratio 3.82; 95% confidence interval 1.95–7.49; P < 0.001) and remained prognostic after adjusting for haematological response, NT-proBNP and longitudinal strain (P < 0.01).

Conclusions

Cardiac amyloid deposits frequently regress following chemotherapy, but only in patients who achieve CR or VGPR. Changes in ECV predict outcome after adjusting for known predictors.
Left atrial appendage mechanical dispersion assessed by speckle-tracking echocardiography as a determinant of left atrial appendage stasis in patients with non-valvular atrial fibrillation
Authors: Mao Y K , Zhao H J , Yu C , Yang Y , Ma M M , Wang Y H , Jiang R H , Zheng Z L , Jiang C Y
Published: October 2022

Background

We sought to investigate the relationship of left atrial appendage (LAA) mechanical dispersion (MD) with LAA dense spontaneous echo contrast (SEC) or thrombus, and to compare its usefulness in the identification of thrombogenesis with left atrial (LA) MD or LA/LAA strain parameters in patients with nonvalvular atrial fibrillation (AF).

Methods

We conducted a cross-sectional study of 493 consecutive patients with AF (median age 65, male 66.9%) who underwent echocardiography prior to catheter ablation. We measured the LAA and LA global longitudinal strain (GLS) using speckle-tracking echocardiography (STE). LAA MD and LA MD was defined as the standard deviation (SD) of time to peak positive strain corrected by the R-R interval.

Results

Patients with LAA dense SEC/thrombus (n=70) had significantly higher LAA MD than controls (n=423) (median 14.20% vs 9.35%). Areas under the receiver-operating curve for CHA2DS2-VASc score plus LAA MD, LAA GLS or LA GLS were comparable (0.830, 0.843 and 0.809) and superior to that combined with LA MD (0.762, all p<0.01). Multivariable analysis showed that LAA MD was an independent determinant of LAA dense SEC/thrombus in four different models (Odds ratio, 1.23–1.24; P<0.001), and provided additional diagnostic value over clinical and standard echocardiographic parameters. Whereas LA MD was not independently associated with LAA dense SEC/thrombus and had no incremental predictive value.

Conclusion

LAA mechanical dispersion provided incremental information over conventional risk factors in the identification of LAA dense SEC or thrombus in AF patients and is superior to LA mechanical dispersion.

Funding Acknowledgement

Type of funding sources: None.
Post-systolic shortening index by echocardiography evaluation of dyssynchrony in the non-dilated and hypertrophied left ventricle
Authors: Wang T K M , Saijo Y , Chan N , Sperry B , Phelan D , Desai M Y , Griffin B P , Grimm R A , Popovic Z B
Published: October 2022

Background

Post-systolic shortening index (PSI) is defined as myocardial shortening that occurs after aortic valve closure, and is an emerging measure of regional LV contractile dysfunction. PSI measurement variability amongst software vendor and its relationship with mechanical dyssynchrony and mechanical dispersion index (MDI) remains unknown. We evaluated PSI by speckle-tracking echocardiography from several vendors in patients with increased left ventricular wall thickness, and associations with MDI.

Methods

This is a prospective cross-sectional study of 70 patients (36 hypertrophic cardiomyopathy [HCM], 18 cardiac amyloidosis and 16 healthy controls) undergoing clinically indicated echocardiography. PSI was measured using QLAB/aCMQ (Philips), QLAB/LV auto-trace (Philips), EchoPAC (GE), Velocity Vector Imaging (Siemens), and EchoInsight (EPSILON) software packages, and calculated as 100% × (post systolic strain − end-systole strain)/post systolic strain.

Results

There was a significant difference in mean PSI among controls 2.1±0.6%, HCM 6.1±2.6% and cardiac amyloidosis 6.8±2.7% (p<0.001). Variations between software vendors were significant in patients with pathologic increases in LV wall thickness (for HCM p=0.03, for amyloidosis p=0.008), but not in controls (p=0.11), as seen in Figure 1. Furthermore, there were moderate correlations between PSI and both MDI (r=0.77) and left ventricular global longitudinal strain (r=0.69), as seen in Figure 2.

Conclusion

PSI was greater in HCM and cardiac amyloidosis patients than controls, and a valuable tool for dyssynchrony evaluation, with moderate correlations to MDI and strain. However, there were significant variations in PSI measurements by software vendor especially in patients with pathological increase in LV wall thickness, suggesting that separate vendor-specific thresholds for abnormal PSI are required.

Funding Acknowledgement

Type of funding sources: None.
Myocardial work impairment in children with Wolff-Parkinson-White syndrome
Authors: Borrelli N , Di Salvo G , Ciriello G D , Sabatino J , Grimaldi N , Barracano R , Fusco F , Merola A , Correra A , Romeo E , Colonna D , Palma M , Scognamiglio G , Russo M G , Sarubbi B
Published: October 2022

Background

Wolf-Parkinson-White Syndrome (WPW) has been associated with reduced local myocardium deformation during systole. According to guidelines, when the left ventricle (LV) dysfunction is present catheter ablation of the accessory pathway may be required, even in asymptomatic patients.

Purpose

The study aimed to assess the diagnostic value of non-invasive myocardial work in predicting subtle myocardial abnormalities in children with WPW.

Methods

Eighty pediatric patients (age 7.91±3.2 years) were included in the study: 20 cases with manifest WPW and 60 age- and sex-matched controls (CTR). Global myocardial work index (MWI) was measured as the area of the LV pressure-strain loops. From MWI, global Constructive Work (MCW), Wasted Work (MWW) and Work Efficiency (MWE) were estimated. In addition, standard echocardiographic parameters of LV function were evaluated.

Results

Patients characteristics are summarized in the table. Despite normal LV EF and GLS, children with WPW had worse MWI (WPW 1292.90±307.67 mmHg% vs CTR 1658.73±241.74 mmHg%, p=0.0000005), MCW (WPW 1844.15±267.96 mmHg% vs CTR 2104.90±237.85 mmHg%, p=0.00009), MWW (WPW 101.5 [85–148.25] mmHg% vs CTR 72 [54.75–109.25] mmHg%, p=0.004) and GWE (WPW 94 [91.75–95] mmHg% vs 96 [95–97] mmHg%, p=0.00012) (table). In the WPW group, MWE (r=−0.6, p=0.009) and MWW (r=0.6, p=0.01) was found to correlate with a prolonged QRS (figure).

A multiple regression model was generated to identify the relation between abnormal myocardial work indices (worst interquartile range as dependent variable) and several independent variables. QRS was the best independent predictor of impaired myocardial work. In particular, a QRS>110 msec showed an 86% sensibility and 85% specificity for abnormal MWE (AUC of 0.85), and a 75% sensibility and 83% specificity for abnormal MWW (AUC of 0.83) (figure).

Conclusion

In children with WPW, myocardial work indices were found significantly reduced, even in presence of normal LV EF and GLS. Prolonged QRS independently predicted myocardial impairment. In pediatric patients with WPW, myocardial work may represent a sensitive measure of LV dysfunction and help in the decision-making.

Funding Acknowledgement

Type of funding sources: None.
Sequential left ventricular electro-mechanical changes in left bundle branch pacing vs right ventricular pacing a two-center study
Authors: Mao Y K , Yang Y , Duchenne J , Garweg C , Sheng X , Zhang J F , Yang Y E , Wang M , Yang Y , Voros G , Sun Y X , Ma M M , Fu G S , Voigt J U
Published: October 2022

Background

Left bundle branch pacing (LBBP) has been proved to maintain electrical synchrony better than RVP during mid to long-term follow-up, but little is known about the left ventricular (LV) mechanical changes over time. This study investigates if LBBP causes less sequential electro-mechanical alterations in LV that develop over time, compared with both conventional (CRVP) and leadless (LRVP) RVP.

Methods

Sixty-five patients with pacing indication for bradycardia were prospectively enrolled: Twenty-two were treated with LBBP, 23 with CRVP and 20 with LRVP. QRS duration (QRSd) was measured at baseline and during follow-up. All patients underwent echocardiography at baseline, one week after implantation and at one-year follow-up. LV volumes, ejection fraction (EF) and global longitudinal strain (GLS) were measured. Septal flash (SF), apical rocking and septal longitudinal strain patterns were assessed visually by two experienced readers.

Results

All the patients presented with normal strain pattern and no signs of SF or apical rocking at baseline. 100% of CRVP and 95% of LRVP patients had stage1 or 2 septal deformation patterns at week 1, and the majority (72.3% CRVP and 83.3% LRVP) progressed to stage≥2 at 12 months. On the contrary, over 2/3 of LBBP patients preserved normal strain patterns at week 1, and less than 1/3 had stage-1 pattern, 2 out of whom progressed to stage-2 during follow-up (Figure 1). At week 1 and 12 months, all RVP patients had SF, and most of them also exhibited apical rocking (87%-94.4% in CRVP and 80%-94.4% in LRVP). However, much less septal flash and apical rocking was induced in LBBP patients at week 1 and last follow-up (27.3%-37.5% and 22.7%-25%, P<0.001 vs RVP). Baseline QRSd were similar among three groups. At week 1, the paced QRSd increased least in LBBP compared to CRVP and LRVP and remained as such at 12 months. During one year follow-up, LVEF and LV GLS decreased more in CRVP group compared to LBBP (both P<0.05) (Figure 2).

Conclusion

LBBP causes less sequential changes in LV deformation patterns, septal flash and apical rocking, compared to CRVP and LRVP. With this, LBBP appears to preserve LV function better than RVP. CRVP and LRVP did not differ in electro-mechanical changes or LV remodeling.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation Flanders (FWO) project grant
Left atrial strain predicts heart failure in the general population
Authors: Nielsen A , Skaarup K , Hauser R , Johansen N , Lassen M , Inciardi R , Jensen G , Schnohr P , Moegelvang R , Biering-Soerensen T
Published: October 2022

Background

Left atrial (LA) function has shown to be a significant predictor of cardiovascular outcomes. We sought to determine the prognostic value of LA strain in relation to incident heart failure (HF) in the general population.

Methods

The present study includes 3,540 participants from the general population without prevalent atrial fibrillation or HF. All participants underwent health examinations and echocardiography including measures of LA function by means of peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA strain during the conduit phase (LACS). Cox proportional hazards regressions were utilised to access the association between incident HF and LA strain parameters.

Results

Median age of the study population was 57 years (interquartile range: 40, 69) and 2,015 (57%) were female. During follow-up (median 5.4 years), 66 (2%) participants were diagnosed with HF. Participants who developed HF had lower PALS (26.4% vs. 36.6%, p<0.001), PACS (15.6% vs. 16.5%, p=0.016), and LACS (11.4% vs. 19.3%, p<0.001) at baseline. Lower values of all three LA strain parameters were associated with a higher risk of developing HF in univariable analysis (Figure 1 & 2). After multivariable adjustments for Framingham Risk Score and global longitudinal strain, PALS (HR=1.06, 95% CI [1.03; 1.09], p<0.001, per 1% decrease), PACS (HR=1.07, 95% CI [1.02; 1.12], p=0.003, per 1% decrease), and LACS (HR=1.05, 95% CI [1.01; 1.10], p=0.016, per 1% decrease) remained significantly associated with incident HF. However, in participants with normal-sized LA (LA volume index <34 ml/m2) and no ischemic heart disease (n=3,046), only PALS and PACS remained independent predictors of HF (Figure 2).

Conclusion

LA strain provides independent prognostic value regarding the risk of incident HF in the general population.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The Danish Heart Foundation and The Metropolitan Region of Denmark
A new way to explore ventricular-arterial coupling in young patients with untreated hypertension
Authors: Trimarchi G , Lofrumento F , Mandraffino G , Verachtert S , Cusma'-Piccione M , De Sarro R , Mancinelli A , Spano' F , Certo G , Morabito A , Di Bella G , Carerj S , Zito C
Published: October 2022

Introduction

Commonly assessed as arterial elastance (Ea) to ventricular end-systolic elastance (Ees) ratio, ventricular-arterial coupling (VAC) has independent prognostic value in hypertension.

Aim

To investigate whether new coupling indices may be able to identify left ventricular (LV) performance changes induced by blood pressure (BP) overload earlier than conventional ones.

Materials and methods

50 young individuals were prospectively enrolled: 25 (40±8 years) newly diagnosed untreated hypertensives and 25 controls (38±9 yrs). All underwent at the same time carotid-femoral pulse wave velocity (PWV) measurement through a tonometer and an echocardiogram to calculate global longitudinal strain (GLS) and myocardial work efficiency (GWE). Two new indices of VAC were derived: PWV/GLS, previously validated and PWV/GWE, still unknown.

Results

ESV/SV ratio was lower in hypertensive (0.48±0.17) than in controls (0.57±0.14) but without any significant difference (p=0.18), whereas PWV/GLS was significantly lower in hypertensives than in controls (−0.45±0.19 vs −0.35±0.09 m/sec%; p=0.02). PWV/GLS ratio correlated with Ea/Ees (r=0.52; p<0.01), diastolic dysfunction degree (r=−0.59; p<0.001), age (r=−0.64; p<0.001), systolic BP (r=−0.41; p=0.002), diastolic BP (r=−0.39; p=0.005) and mean arterial pressure (MAP) (r=−0.40; p=0.004). PWV/GWE was higher in hypertensives than in controls (0.10±0.02 vs 0.08±0.01 m/sec%; p=0.001) and it was associated with Ea/Ees (r=−0.55; p=0.006), age (r=0.59; p<0.001), diastolic dysfunction degree (r=0.55; p<0.001), systolic BP (r=0.8; p<0.001), diastolic BP (r=0.5; p<0.001) and MAP (r=0.52; p<0.001).

Conclusions

Innovative indices of ventricular-arterial coupling could be more sensitive for investigating the impact of hypertension on LV performance.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): G. Martino University Hospital, Department of Clinical and Experimental Medicine - Cardiology Unit, University of Messina, Messina, Italy
Phenotyping Acute Decompensated Heart Failure (ADHF)by a cardiac speckle tracking analysis
Authors: Barki M , Losito M , Bandera F , Alfonzetti E , Caracciolo M M , Rovida M , Guazzi M
Published: October 2022

Background

The global longitudinal strain (GLS) evaluation by Speckle Tracking Echocardiography (STE) is an established non-invasive, highly reproducible echocardiographic prognostic index in Heart Failure (HF). In acute decompensated heart failure (ADHF), GLS has proved to have greater prognostic value than left ventricular ejection fraction (LVEF) in the categorization of HF. However, how GLS may change over hospital staying in ADHF and how it correlates with Left Atrial (LA) functioning and contractile reserve in this cohort of subjects is currently undefined.

Aims

To evaluate, in a cohort of ADHF patients, GLS extent of changes after targeted anti-congestion therapy and its correlation with LA mechanics and reservoir function.

Methods

Eighty-five ADHF patients (mean age 75.6±10.4 years, 59% males) were prospectively enrolled within 24 hours from admission to the emergency department (ED). In either the acute phase and at pre-discharge all patients underwent laboratory tests, Lung Ultrasonography (LUS), M-Mode, 2-Dimensions and Doppler Echocardiography. LA dynamics assessment was based on the evaluation of LA strain, particularly through Global-Peak Atrial Longitudinal Strain (GPALS). Strain analysis by STE was performed offline.

Results

From admission to discharge, despite decongestion as shown by a significant reduction of the number of B-lines measured at LUS and NT-proBNP at blood tests (B-lines: 22.2±17.1 vs. 6.5±5 p<0.001; NT-proBNP: 8738±948 ng/l vs 4227±659 ng/l p<0.001), we observed only minimal and non-significant changes in the average GLS (from −12.2±4% at admission to −12.5±3.8% at discharge; p=0.8) and GPALS (from 13.2±7.6% at admission to 13.6±7.8% at discharge; p=0.77) (Table 1). Interestingly, when evaluated with Pearson's coefficient, in the whole population a significant direct correlation was observed between GLS and GPALS values at discharge (r=0.6, 95% Confidence Interval (CI) 0.55–0.7; p<0.001) (Figure 1) as well as between ΔGLS and ΔGPALS (r=0.42 95% CI 0.21–0.59, p=0.02).

Conclusions

In patients hospitalized for ADHF a significant impairment of GLS occurs and no improvement is observed at discharge after decongestion. The LA dynamics correlates with, and is likely involved in, this lack of changes. In this subset of patients, the dissociation between decongestion and LV and LA dynamics evaluated by strain analysis suggest the importance to monitor these functional indicators in order to improve risk stratification and reduce early re-hospitalization for AHF.

Funding Acknowledgement

Type of funding sources: None.
Global longitudinal strain to predict myocardial fibrosis in patients in carbon monoxide poisoning
Authors: Kim Y , Cho D H , Cha Y S , Son J W
Published: October 2022

Background

Carbon monoxide (CO) inhibits oxygen delivery and subsequently causes ischemic changes that can lead to myocardial damage. Late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) reflects myocardial fibrosis and detects subclinical myocardial damage in patients with acute CO poisoning. However, CMR is expensive and hard to perform in patients with neurologic deficit. Therefore, this study aims to investigate which echocardiographic parameters could predict the presence of myocardial fibrosis represented by LGE in CO intoxication patients.

Methods

This prospective observational study included 128 consecutive patients (Mean age: 52.2±16.2) with acute CO poisoning and elevated troponin I (defined as >0.045 ng/mL) at the emergency department of a tertiary university hospital. All participants underwent hyperbaric oxygen therapy (HBOT). CMR and conventional echocardiography with 2D speckle-tracking were performed within 7 days. Subjects were categorized into late gadolinium enhancement (LGE) and no LGE group according to the CMR findings.

Results

Mean left ventricular (LV) ejection fraction (EF) and global longitudinal strain (GLS) were 57.0±10.0% and −16.3±3.7% respectively. LGE was observed in 89 (69.5%) patients and the most common pattern was mid-wall involvement. Clinical characteristics such as age, sex, shock, time elapsed from rescue to HBOT, and the level of troponin I were not different between groups with LGE and without LGE. Among echocardiographic parameters, LV EF was not significantly different between groups (LGE: 56.0±10.5% vs 59.3±8.1%, p=0.089). LV GLS was more impaired in patients with LGE compared to those without LGE (−15.7±3.8% vs −17.9±3.0%, p=0.003). In multivariate logistic analysis, LV GLS was independently associated with the presence of LGE [Odds ratio (OR) 1.279, 95% confidence interval (CI) (1.047–1.563), p=0.016], but not LV EF.

Conclusion

In patients with acute CO poisoning and elevated troponin I, LV GLS predicted the presence of LGE in CMR. These finding suggest that subclinical myocardial dysfunction represented by LV GLS may reflect the burden of CO induced myocardial fibrosis.

Funding Acknowledgement

Type of funding sources: None.
Machine-learning algorithms for prediction of survival by stress echocardiography in chronic coronary syndromes
Authors: Gaibazzi N , Cortigiani L , Ciampi Q , Lorenzoni G , Rigo F , Gherardi S , Bovenzi F , Gregori D , Picano E
Published: October 2022

Background

Stress echocardiography (SE) is based on regional wall motion abnormalities and coronary flow velocity reserve (CFVR). They recognise different and complementary pathophysiological targets, and show independent and incremental value in predicting survival [1]. The approach based on machine-learning (ML) has the recognised potential to identify unsuspected patterns, and this can be especially relevant in the field of risk stratification by cardiac functional stress testing due to multiple parameters used in comprehensive stress testing and the variable weight of covariates [2].

Aim

To assess SE outcome data analysis with ML approach.

Methods

We included 6,881 prospectively recruited and retrospectively analyzed patients (median age 67 years, IQR 59–74) with suspected (n=4,279) or known (n=2,602) coronary artery disease submitted to clinically-driven dipyridamole SE in 5 Italian institutions (Figure 1). The primary outcome measure was all-cause death. A Random Forest Survival model has been implemented to model the survival function according to the patient's characteristics. The Random Forest predicted response dependency on covariates has been investigated by reporting the variable dependence and the partial dependency plot (Figure 2). A web application was developed to predict the survival function according to the patients' characteristics. The external validation cohort was made of additional 1,002 patients recruited by a single, independent center in the same time period.

Results

During a median duration of follow-up of 3.4 years (IQR 1.6–7.5), 814 (12%) patients died. The mortality risk was higher for patients aged more than 60 years, resting ejection fraction <60%, resting WMSI, positive delta WMSI scores, and CFVR <3.0. The C-index performance (perfect prediction=1) was 0.79 in the internal validation cohort and 0.81 in the external, independent validation data set. Survival functions for individual patient were easily obtained with an open-access web-app.

Conclusion

An ML approach can be fruitfully applied to outcome data obtained with SE. Survival showed a constantly increasing relationship between survival and CFVR <3.0 and stress-rest wall motion score index >0. Since processing is largely automated, this approach can be easily scaled to larger and more comprehensive data sets to further refine stratification, guide therapy and be ultimately adopted as an open-source on-line decision tool.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The study was partially funded by CNR-MIUR (National Research Council, Italian Ministry of University and Research) Ageing subproject.
Haemodynamic indicators of arteriolar dysregulation during combined hyperventilation and exercise test in patients with ANOCA (SESPASM)
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: October 2022

Introduction

In patients with angina and non-obstructed coronary arteries (ANOCA), functional dysregulation such as epicardial coronary spasm and microvascular dysfunction (microvascular spasm and /or impaired microvascular dilatation) frequently coexist.

The aim was to analyse haemodynamic indicators of arteriolar dysregulation during combined hyperventilation and exercise stress echo test in patients with ANOCA.

Methods

In a prospective study we enrolled 38 patients (56±13 years, 31 females) with ANOCA, proven by normal coronary angiogram. Stress echocardiography protocol with Doppler measurements of coronary flow consisted of hyperventilation test for spasm provocation (HYP, respiratory rate of 30 per min for 5') followed by supine bicycle exercise test (HYP+EXE) for assessment of endothelium dependent function. Adenosine test was done (ADO 140 mcg/kg in 1 min) for estimation of endothelium independent vasodilatation. Coronary flow velocity (CFV) was assessed in distal LAD by Transthoracic Doppler echocardiography at the end of the each stage of the test. Abnormal response to HYP was a CFV ratio (stress/rest) <1.0 (vasoconstrictor response). CFV ratio at peak HYP+ EXE was an indicator of endothelial dependent vasodilatation (<2 blunted response). An abnormal response to ADO was a CFV reserve <2.0 (blunted vasodilatory response).

Results

The double product increased during HYP in comparison to rest (13263 vs 10321, p<0.001), and further increased with EXE (23817 vs HYP, p<0.001). Chest pain was present in 6 pts during HYP, and in additional three pts during HYP+EXE (15.8% vs 23.7%, p=0.25). ST segment depression was present in 6 pts during HYP and 23 during HYP+EXE (15.79% vs 60.52%, p<0.001). Wall motion abnormality was provoked with HYP in three pts (7.89%) and in ten (26.3%) with HYP+EXE (p=0.016). CFV ratio was abnormal for vasoconstriction during HYP in 16 (42.1%) and blunted in 23 (60.52%) pts during HYP+EXE (Fig 1). Vasodilation during ADO was preserved in all patients, but one. There was significant difference between CFV reserve during HYP+EXE vs ADO (1.98±0.49 vs 2.53±0.43 respectively, p<0.001) (Fig. 2).

Conclusion

Our results indicate that HYP induce microvascular dysfunction with vasospastic component which is reflected in reduced CFV ratio. This prevents the normal hyperemic response during EXE in more than a half of patients. Endothelial independent vasodilatation during ADO hyperemia was perserved in all patients, excluding structural microvasculature remodeling. HYP+EXE provocation with noninvasive measurement of coronary flow is a promising test for assessing mechanism of arteriolar dysregulation in ANOCA patients.

Funding Acknowledgement

Type of funding sources: None.
Three-dimensional left and right atrioventricular coupling indices as prognostic markers in heart failure with reduced ejection fraction
Authors: Vijiiac A E , Scarlatescu A , Verinceanu V , Cojocaru C , Petre I , Onciul S , Dorobantu M , Vatasescu R
Published: October 2022

Background

While left atrial and left ventricular functional parameters are established prognostic markers in heart failure (HF), recent studies suggest that parameters assessing the atrio-ventricular interaction are better predictors. Left atrioventricular coupling index (LACI) assessed with cardiac magnetic resonance is an emerging outcome predictor in HF patients, however its assessment by three-dimensional (3D) echocardiography hasn't been studied so far. Moreover, the role of the right atrioventricular coupling index (RACI) in HF remains to be established.

Purpose

We sought to evaluate the LACI, RACI and combined left and right atrioventricular coupling index (CACI) with 3D echocardiography in a cohort of patients with HF and reduced ejection fraction (HFrEF) and to assess their prognostic role.

Methods

We prospectively enrolled 60 consecutive patients with HFrEF in sinus rhythm, who underwent two dimensional and 3D echocardiographic acquisitions. LACI was calculated as the ratio between 3D left atrial and 3D left ventricular end-diastolic volumes. RACI was calculated as the ratio between 3D right atrial and 3D right ventricular end-diastolic volumes. CACI was defined as the sum between LACI and RACI. Patients were followed for major adverse cardiac events (MACE), defined as a composite endpoint of cardiac death or HF decompensation requiring hospitalization.

Results

After a mean follow-up of 19±9 months, 33 patients reached the endpoint. Patients with MACE had higher LACI (33.5±21.1% vs. 19.9±12.4%, p=0.003), higher RACI (33.6±23.6% vs. 20.8±13.8%, p=0.01) and higher CACI (67.0±38.0% vs. 40.7±24.4%, p=0.002) – suggestive of atrioventricular decoupling. In ROC analysis, CACI had the best AUC for event prediction (AUC=0.750, p=0.001, cut-off=42.8%, Sen=69.7%, Spe=77.7%), followed by LACI (AUC=0.745, p=0.001, cut-off=20.4%, Sen=72.7%, Spe=70.4%), and then RACI (AUC=0.717, p=0.004, cut-off=18.6%, Sen=75.8%, Spe=70.4%).

In unadjusted Cox regression, all three atrioventricular coupling indices were predictors of MACE: HR=3.30 [95% CI, 1.52–7.14], p=0.002 for LACI, HR=4.54 [95% CI, 2.03–10.17], p<0.001 for RACI, HR=3.87 [95% CI, 1.82–8.23], p<0.001 for CACI. A multivariable model was constructed using well-established event predictors in HFrEF: age, global longitudinal strain of the left ventricle, global longitudinal strain of the right ventricular free wall and pulmonary artery systolic pressure. All three atrioventricular coupling indices remained independent predictors of MACE in multivariable regression: HR=3.11 [95% CI, 1.36–7.14], p=0.007 for LACI, HR=4.38 [95% CI, 1.84–10.41], p=0.001 for RACI, HR=3.98 [95% CI, 1.75–9.03], p=0.001 for CACI.

Conclusion

Greater 3D LACI, RACI and CACI, reflecting atrioventricular uncoupling, are all independent prognostic markers in HFrEF.

Funding Acknowledgement

Type of funding sources: None.
The association between frailty and physical performance in elderly patients with heart failure
Authors: Jin U , Lee C J , Yoon M , Ha J , Oh J , Park S , Lee S H , Kang S M
Published: October 2022

Background

Frailty is known to be an important prognostic indicator in heart failure (HF). The Korean version of the frail scale for Koreans (K-FRAIL) has been developed and verified. The purpose of this study is to analyze the relationship between the K-FRAIL scale and physical performance, including muscular fitness and aerobic capacity in patients with HF.

Methods

This study included 143 HF patients aged over 65 years from a single tertiary hospital. In these subjects, muscular fitness was assessed using the handgrip test and knee extensor strength measurement, and aerobic capacity was assessed by cardiopulmonary exercise test and 6-minute walk test. Frailty status was measured using the K-FRAIL questionnaire and was classified as robust (K-FRAIL scale: 0), prefrail (1–2), and frail (3–5).

Results

Mean age of participants with robust (N=37), prefrail (N=75), and frail (N=31) were 72.5, 73.5, and 76.3 years, respectively. There was no difference in sex and left ventricular ejection fraction (LVEF) among groups, but the estimated glomerular filtration rate (eGFR) was significantly lower as frailty status increased (75.6±17.2 vs. 70.0±20.5 vs. 56.1±23.7 mL/min/1.73 m2; P<0.001). Hand-grip strength and knee extensor muscle strength did not differ among groups. However, peak oxygen consumption (peak VO2; 22.8±5.0 vs. 19.3±4.6 vs. 16.9±4.7 mL/kg/min, P<0.001) and 6-min walk distance (458.4±68.2 vs. 404.5±92.3 vs. 311.2±120.5 m; p<0.001) significantly decreased according to frailty severity. In multivariate regression analysis adjusted for age, sex, haemoglobin, eGFR and LVEF, peak VO2 (β=−0.311; P=0.002) and 6-min walk distance (β=−0.384; P<0.001) showed a significant inverse association with the K-FRAIL scale. With the cut-off value from receiver-operating characteristic curve analysis, peak VO2 (hazard ratio, 5.08; p=0.023) and 6MWT (hazard ratio, 3.99; p=0.020) were independent predictor of frailty according to K-FRAIL scale.

Conclusion

In elderly HF patients, physical performance differs according to frailty status, peak VO2 and 6-min walk distance correlates with the K-FRAIL scale better than muscular fitness.

Funding Acknowledgement

Type of funding sources: None.