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result(s) for
"Hess, Sebastien"
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Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra
by
Branduardi-Raymont, Graziella
,
Krupp, Norbert
,
Tao, Chihiro
in
Aerospace Technology and Astronautics
,
Astrophysics
,
Astrophysics and Astroparticles
2015
The ionospheric response to auroral precipitation at the giant planets is reviewed, using models and observations. The emission processes for aurorae at radio, infrared, visible, ultraviolet, and X-ray wavelengths are described, and exemplified using ground- and space-based observations. Comparisons between the emissions at different wavelengths are made, where possible, and interpreted in terms of precipitating particle characteristics or atmospheric conditions. Finally, the spatial distributions and dynamics of the various components of the aurorae (moon footprints, low-latitude, main oval, polar) are related to magnetospheric processes and boundaries, using theory, in situ, and remote observations, with the aim of distinguishing between those related to internally-driven dynamics, and those related to the solar wind interaction.
Journal Article
Drifting discrete Jovian radio bursts reveal acceleration processes related to Ganymede and the main aurora
by
Mauduit, Emilie
,
Zarka, Philippe
,
Lamy, Laurent
in
639/33/445/846
,
639/33/525/868
,
639/33/525/869
2023
Radio detection at high time-frequency resolutions is a powerful means of remotely studying electron acceleration processes. Radio bursts have characteristics (polarization, drift, periodicity) making them easier to detect than slowly variable emissions. They are not uncommon in solar system planetary magnetospheres, the powerful Jovian “short bursts (S-bursts)\" induced by the Io-Jupiter interaction being especially well-documented. Here we present a detection method of drifting radio bursts in terabytes of high resolution time-frequency data, applied to one month of ground-based Jupiter observations. Beyond the expected Io-Jupiter S-bursts, we find decameter S-bursts related to the Ganymede-Jupiter interaction and the main Jovian aurora, revealing ubiquitous Alfvénic electron acceleration in Jupiter’s high-latitude regions. Our observations show accelerated electron energies are distributed in two populations, kilo-electron-Volts and hundreds of electron-Volts. This detection technique may help characterizing inaccessible astrophysical sources such as exoplanets.
Jovian short bursts (S-bursts) are induced by the Io-Jupiter interaction. Here, the authors show a drifting radio burst detection method and report S-bursts related to Ganymede-Jupiter interaction and to Jovian aurora.
Journal Article
Discrepancy in Von Willebrand Abnormalities Between Degenerative and Functional Mitral Regurgitation
by
Grunebaum, Lelia
,
Reydel, Antje
,
Trimaille, Antonin
in
Abnormalities
,
Adenosine diphosphate
,
Etiology
2021
According to the etiology, MR can be classified as functional MR (FMR) or degenerative MR (DMR). [...]CT-ADP prolongation is not specific of HMW VWF defect and could be influenced by various hematologic parameters and P2Y12 inhibitors. [...]acquired von Willebrand syndrome in severe MR may solely occurs in DMR, and appears to be reversible with Mitraclip.Disclosures Dr. Matsushita has received scholarship from Edwards Lifesciences.
Journal Article
Acute kidney injury and acute kidney recovery following Transcatheter Aortic Valve Replacement
by
Reydel, Antje
,
Trimaille, Antonin
,
Kibler, Marion
in
Aorta
,
Aortic valve
,
Auroral kilometric radiation
2021
Acute kidney injury (AKI) is associated with a dismal prognosis in Transcatheter Aortic Valve replacement (TAVR). Acute kidney recovery (AKR), a phenomenon reverse to AKI has recently been associated with better outcomes. Between November 2012 to May 2018, we explored consecutive patients referred to our Heart Valve Center for TAVR. AKI was defined according to the VARC-2 definition. Mirroring the VARC-2 definition of AKI, AKR was defined as a decrease in serum creatinine ([greater than or equal to]50%) or [greater than or equal to]25% improvement in GFR up to 72 hours after TAVR. AKI and AKR were respectively observed in 8.3 and 15.7% of the 574 patients included. AKI and AKR patients were associated to more advanced kidney disease at baseline. At a median follow-up of 608 days (range 355-893), AKI and AKR patients experienced an increased cardiovascular mortality compared to unchanged renal function patients (14.6% and 17.8% respectively, vs. 8.1%, CI 95%, p<0.022). Chronic kidney disease, (HR: 3.9; 95% CI 1.7-9.2; p < 0.001) was the strongest independent factor associated with AKI similarly to baseline creatinine level (HR: 1; 95% CI 1 to 1.1 p < 0.001) for AKR. 72-hours post procedural AKR (HR: 2.26; 95% CI 1.14 to 4.88; p = 0.021) was the strongest independent predictor of CV mortality. Both AKR and AKI negatively impact long term clinical outcomes of patients undergoing TAVR.
Journal Article
Acute kidney injury and acute kidney recovery following Transcatheter Aortic Valve Replacement
by
Reydel, Antje
,
Trimaille, Antonin
,
Kibler, Marion
in
Acute Kidney Injury - etiology
,
Aged
,
Aged, 80 and over
2021
Acute kidney injury (AKI) is associated with a dismal prognosis in Transcatheter Aortic Valve replacement (TAVR). Acute kidney recovery (AKR), a phenomenon reverse to AKI has recently been associated with better outcomes.
Between November 2012 to May 2018, we explored consecutive patients referred to our Heart Valve Center for TAVR. AKI was defined according to the VARC-2 definition. Mirroring the VARC-2 definition of AKI, AKR was defined as a decrease in serum creatinine (≥50%) or ≥25% improvement in GFR up to 72 hours after TAVR.
AKI and AKR were respectively observed in 8.3 and 15.7% of the 574 patients included. AKI and AKR patients were associated to more advanced kidney disease at baseline. At a median follow-up of 608 days (range 355-893), AKI and AKR patients experienced an increased cardiovascular mortality compared to unchanged renal function patients (14.6% and 17.8% respectively, vs. 8.1%, CI 95%, p<0.022). Chronic kidney disease, (HR: 3.9; 95% CI 1.7-9.2; p < 0.001) was the strongest independent factor associated with AKI similarly to baseline creatinine level (HR: 1; 95% CI 1 to 1.1 p < 0.001) for AKR. 72-hours post procedural AKR (HR: 2.26; 95% CI 1.14 to 4.88; p = 0.021) was the strongest independent predictor of CV mortality.
Both AKR and AKI negatively impact long term clinical outcomes of patients undergoing TAVR.
Journal Article
Determinants and treatments of heart failure after transcatheter aortic valve implantation: moving up a notch
by
Reydel, Antje
,
Trimaille, Antonin
,
Kibler, Marion
in
Aged
,
Aortic stenosis
,
Aortic Valve - surgery
2023
Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical aortic valve replacement for patients with symptomatic severe aortic stenosis in elderly and comorbid population. Significant improvement in heart function has been observed in patients undergoing TAVI, but numerous patients are readmitted to hospital for heart failure (HF). Moreover, repeat HF hospitalization is strongly associated with an adverse prognosis and increases the financial burden of health care. Although studies have identified pre‐existing and post‐procedural factors that contribute to HF hospitalization after TAVI, there is a paucity of data regarding optimal post‐procedural pharmacological treatments. This review aims to provide an overview of the current understanding of mechanisms, determinants, and potential treatments of HF following TAVI. We first review the pathophysiology of left ventricular (LV) remodelling, coronary microcirculation disorder, and endothelial dysfunction in patients with aortic stenosis and then examine the impact of TAVI on these conditions. We then present evidence of various factors and complications that may interplay with LV remodelling and contribute to HF events after TAVI. Next, we describe the triggers and predictors of early and late HF rehospitalizations following TAVI. Lastly, we discuss the potential of conventional pharmacological treatments, including renin–angiotensin blockers, beta‐blockers, and diuretics in TAVI patients. The paper explores the potential of newer drugs, including sodium–glucose co‐transporter 2 inhibitors, anti‐inflammatory drugs, and ion supplementation. Comprehensive knowledge in this field may aid in recognizing successful existing therapies, developing effective new treatments, and establishing dedicated patient care strategies during follow‐up after TAVI.
Journal Article
Impact of Primary Hemostasis Disorders on Late Major Bleeding Events among Anticoagulated Atrial Fibrillation Patients Treated by TAVR
by
Reydel, Antje
,
Trimaille, Antonin
,
Kibler, Marion
in
Adenosine diphosphate
,
Anticoagulants
,
Blood
2021
Background: Bleeding events are among the striking complications following transcatheter aortic valve replacement (TAVR), and bleeding prediction models are crucially warranted. Several studies have highlighted that primary hemostasis disorders secondary to persistent loss of high-molecular-weight (HMW) multimers of the von Willebrand factor (vWF) and assessed by adenosine diphosphate closure time (CT-ADP) may be a strong predictor of late major/life-threatening bleeding complications (MLBCs). Pre-existing atrial fibrillation (AF) is a frequent comorbidity in TAVR patients and potentially associated with increased bleeding events after the procedure. Objectives: This study evaluated the impact of ongoing primary hemostasis disorders, as assessed by post-procedural CT-ADP > 180 s, on clinical events after TAVR among anticoagulated AF patients. Methods: An ongoing primary hemostasis disorder was defined by post-procedure CT-ADP > 180 s. Bleeding complications were assessed according to the Valve Academic Research Consortium-2 (VARC-2) criteria. The primary endpoint was the occurrence of late MLBCs at one-year follow-up. The secondary endpoint was a composite of mortality, stroke, myocardial infarction, and rehospitalization for heart failure. Results: In total, 384 TAVR patients were included in the analysis. Of these patients, 57 patients (14.8%) had a prolongated CT-ADP > 180 s. Increased MLBCs were observed in patients with CT-ADP > 180 s (35.1% versus 1.2%; p < 0.0001). Conversely, the occurrence of the composite endpoint did not differ between the groups. Multivariate analysis identified CT-ADP > 180 s (HR 28.93; 95% CI 9.74–85.95; p < 0.0001), bleeding history, paradoxical aortic stenosis (AS), and major vascular complications following TAVR as independent predictors of late MLBCs. Conclusion: Among patients with anticoagulated AF, a post-procedural CT-ADP > 180 s was identified as a strong independent predictor of late MLBCs. These findings suggest that persistent primary hemostasis disorders contribute to a higher risk of late bleeding events and should be considered for a tailored, risk-adjusted antithrombotic therapy after TAVR.
Journal Article
Bitcoin and Its Energy, Environmental, and Social Impacts: An Assessment of Key Research Needs in the Mining Sector
2023
In this study, we used a combination of AI-assisted analysis of social media discourse and collaboration with industry experts to delve into the key research needs associated with the Bitcoin mining industry. We identified primary threats, opportunities, and research questions related to the Bitcoin mining industry and its wider impacts, focusing on its energy use and environmental footprint. Our findings spotlight the industry’s move towards increasingly greater energy efficiency and an emerging commitment to renewable energy, highlighting its potential to contribute to the coming energy transition. We underscore the transformative potential of emerging applications in the Bitcoin mining sector, especially regarding demand response, grid flexibility, and methane mitigation. We suggest that targeted research on Bitcoin can serve policymakers, private sector decision-makers, research funding agencies, environmental scientists, and the Bitcoin industry itself. We propose that filling key information gaps could help clarify the risks and benefits of Bitcoin mining by encouraging collaboration among researchers, policymakers, and industry stakeholders and conducting research that provides baseline peer-reviewed evidence surrounding Bitcoin’s production and impacts. A collaborative approach could help mitigate the risks and realize the benefits of Bitcoin mining, including potentially positive and substantive contributions in alignment with the Sustainable Development Goals.
Journal Article
Increased susceptibility to SARS‐CoV‐2 infection in patients with reduced left ventricular ejection fraction
by
Cardi, Thomas
,
Reydel, Antje
,
Trimaille, Antonin
in
Acute coronary syndrome
,
Acute Coronary Syndrome - complications
,
Acute coronary syndromes
2021
Aims Cardiovascular disease has been recognized as a major determinant of coronavirus disease 2019 (COVID‐19) vulnerability and severity. Angiotensin‐converting enzyme (ACE) 2 is a functional receptor for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and is up‐regulated in patients with heart failure. We sought to examine the potential association between reduced left ventricular ejection fraction (LVEF) and the susceptibility to SARS‐CoV‐2 infection. Methods and results Of the 1162 patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention between February 2014 and October 2018, we enrolled 889 patients with available clinical follow‐up data. Follow‐up was conducted by telephone interviews 1 month after the start of the French lockdown which began on 17 March 2020. Patients were divided into two groups according to LVEF <40% (reduced LVEF) (n = 91) or ≥40% (moderately reduced + preserved LVEF) (n = 798). The incidence of COVID‐19‐related hospitalization or death was significantly higher in the reduced LVEF group as compared with the moderately reduced + preserved LVEF group (9% vs. 1%, P < 0.001). No association was found between discontinuation of ACE‐inhibitor or angiotensin‐receptor blockers and COVID‐19 test positivity. By multivariate logistic regression analysis, reduced LVEF was an independent predictor of COVID‐19 hospitalization or death (odds ratio: 6.91, 95% confidence interval: 2.60 to 18.35, P < 0.001). Conclusions In a large cohort of patients with previous ACS, reduced LVEF was associated with increased susceptibility to COVID‐19. Aggressive COVID‐19 testing and therapeutic strategies may be considered for patient with impaired heart function.
Journal Article
Risk and Severity of COVID-19 and ABO Blood Group in Transcatheter Aortic Valve Patients
by
Reydel, Antje
,
Gennesseaux, Gabrielle
,
Trimaille, Antonin
in
Aortic stenosis
,
Blood groups
,
Cancer
2020
While cardiovascular disease has been associated with an increased risk of coronavirus disease 2019 (COVID-19), no studies have described its clinical course in patients with aortic stenosis who had undergone transcatheter aortic valve replacement (TAVR). Numerous observational studies have reported an association between the A blood group and an increased susceptibility to SARS-CoV-2 infection. Our objective was to investigate the frequency and clinical course of COVID-19 in a large sample of patients who had undergone TAVR and to determine the associations of the ABO blood group with disease occurrence and outcomes. Patients who had undergone TAVR between 2010 and 2019 were included in this study and followed-up through the recent COVID-19 outbreak. The occurrence and severity (hospitalization and/or death) of COVID-19 and their associations with the ABO blood group served as the main outcome measures. Of the 1125 patients who had undergone TAVR, 403 (36%) died before 1 January 2020, and 20 (1.8%) were lost to follow-up. The study sample therefore consisted of 702 patients. Of them, we identified 22 cases (3.1%) with COVID-19. Fourteen patients (63.6%) were hospitalized or died of disease. Multivariable analysis identified the A blood group (vs. others) as the only independent predictor of COVID-19 in patients who had undergone TAVR (odds ratio (OR) = 6.32; 95% confidence interval (CI) = 2.11−18.92; p = 0.001). The A blood group (vs. others; OR = 8.27; 95% CI = 1.83−37.43, p = 0.006) and a history of cancer (OR = 4.99; 95% CI = 1.64−15.27, p = 0.005) were significantly and independently associated with disease severity (hospitalization and/or death). We conclude that patients who have undergone TAVR frequently have a number of cardiovascular comorbidities that may work to increase the risk of COVID-19. The subgroup with the A blood group was especially prone to developing the disease and showed unfavorable outcomes.
Journal Article