21 research outputs found

    Relationship between low Ankle-Brachial Index and rapid renal function decline in patients with atrial fibrillation: A prospective multicentre cohort study

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    OBJECTIVE: To investigate the relationship between Ankle-Brachial Index (ABI) and renal function progression in patients with atrial fibrillation (AF). DESIGN: Observational prospective multicentre cohort study. SETTING:Atherothrombosis Center of I Clinica Medica of 'Sapienza' University of Rome; Department of Medical and Surgical Sciences of University Magna Græcia of Catanzaro; Atrial Fibrillation Registry for Ankle-Brachial Index Prevalence Assessment-Collaborative Italian Study. PARTICIPANTS: 897 AF patients on treatment with vitamin K antagonists. MAIN OUTCOME MEASURES: The relationship between basal ABI and renal function progression, assessed by the estimated Glomerular Filtration Rate (eGFR) calculated with the CKD-EPI formula at baseline and after 2 years of follow-up. The rapid decline in eGFR, defined as a decline in eGFR >5 mL/min/1.73 m(2)/year, and incident eGFR<60 mL/min/1.73 m(2) were primary and secondary end points, respectively. RESULTS: Mean age was 71.8±9.0 years and 41.8% were women. Low ABI (ie, ≤0.90) was present in 194 (21.6%) patients. Baseline median eGFR was 72.7 mL/min/1.73 m(2), and 28.7% patients had an eGFR60 mL/min/1.73 m(2), 153 (23.9%) had a reduction of the eGFR <60 mL/min/1.73 m(2). ABI ≤0.90 was also an independent predictor for incident eGFR<60 mL/min/1.73 m(2) (HR 1.851, 95% CI 1.205 to 2.845, p=0.005). CONCLUSIONS: In patients with AF, an ABI ≤0.90 is independently associated with a rapid decline in renal function and incident eGFR<60 mL/min/1.73 m(2). ABI measurement may help identify patients with AF at risk of renal function deterioration

    Frequency of left ventricular hypertrophy in non-valvular atrial fibrillation

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    Left ventricular hypertrophy (LVH) is significantly related to adverse clinical outcomes in patients at high risk of cardiovascular events. In patients with atrial fibrillation (AF), data on LVH, that is, prevalence and determinants, are inconsistent mainly because of different definitions and heterogeneity of study populations. We determined echocardiographic-based LVH prevalence and clinical factors independently associated with its development in a prospective cohort of patients with non-valvular (NV) AF. From the "Atrial Fibrillation Registry for Ankle-brachial Index Prevalence Assessment: Collaborative Italian Study" (ARAPACIS) population, 1,184 patients with NVAF (mean age 72 \ub1 11 years; 56% men) with complete data to define LVH were selected. ARAPACIS is a multicenter, observational, prospective, longitudinal on-going study designed to estimate prevalence of peripheral artery disease in patients with NVAF. We found a high prevalence of LVH (52%) in patients with NVAF. Compared to those without LVH, patients with AF with LVH were older and had a higher prevalence of hypertension, diabetes, and previous myocardial infarction (MI). A higher prevalence of ankle-brachial index 640.90 was seen in patients with LVH (22 vs 17%, p = 0.0392). Patients with LVH were at significantly higher thromboembolic risk, with CHA2DS2-VASc 652 seen in 93% of LVH and in 73% of patients without LVH (p &lt;0.05). Women with LVH had a higher prevalence of concentric hypertrophy than men (46% vs 29%, p = 0.0003). Logistic regression analysis demonstrated that female gender (odds ratio [OR] 2.80, p &lt;0.0001), age (OR 1.03 per year, p &lt;0.001), hypertension (OR 2.30, p &lt;0.001), diabetes (OR 1.62, p = 0.004), and previous MI (OR 1.96, p = 0.001) were independently associated with LVH. In conclusion, patients with NVAF have a high prevalence of LVH, which is related to female gender, older age, hypertension, and previous MI. These patients are at high thromboembolic risk and deserve a holistic approach to cardiovascular prevention

    Application of LPV modeling, design and analysis methods to a re-entry vehicle

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    In this paper the application of linear parameter varying (LPV) modeling, design and analysis methods to a re-entry vehicle is presented The selected atmospheric re-entry benchmaik includes full nonlinear motion, a detailed aerodynamic database (from hypersonic to subsonic), relevant actuator and sensor models and physically-meaningful aerodynamic and parametric uncertainty profiles The results show that (i) LPV controller design methods can solve gain-scheduling problems in a very effective manner, (ii) integral quadratic constraint (IQC) analysis methods can be used very efficiently to accurately interpret the nonlinear time domain simulation results, and, (iii) the use of linear fractional transfoi mation (LFT) and LPV modeling representations are key to a successful analysi

    Mission Analysis, GNC and ATD for Reusable Launch Vehicles within ASCenSIon: Multi-Orbit Multi-Payload Injection, Re-Entry and Safe Disposal

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    Reusable Launch Vehicles (RLVs) are not only key for an economically and ecologically sustainable space access but also represent a paramount innovation towards the increasing demand for smaller satellites and mega- constellations. In order to ensure Europe's independent space access capabilities, ASCenSIon (Advancing Space Access Capabilities - Reusability and Multiple Satellite Injection) is born as an innovative training network with fifteen Early Stage Researchers, ten beneficiaries, and fourteen partner organisations across Europe. This paper provides an overview of the mission, ranging from the ascent to the re-entry of the reusable stages and including the multi-orbit injection and the safe disposal. A special focus is put on the activities developed within ASCenSIon regarding Mission Analysis (MA), Guidance Navigation and Control (GNC) and Aerothermodynamics (ATD). The foreseen methods, approaches and goals of the project are presented. These topics require innovation within and a high level of collaboration due to their interconnection. The pre-flight design capability drives the necessity of a MA and GNC missionisation tool coupled with ATD software to test/explore re-entry solutions. Such a reliable and efficient tool will require the development of GNC algorithms for the re-entry of the launcher. Additionally, specific challenges of trajectory optimization for RLVs are addressed, such as integrated multi-disciplinary vehicle design and trajectory analysis, fast and reliable on-board methods. The results of this study are subsequently used to develop the controlled strategy. Moreover, to perform the novel multi-orbit multi-payload injection. This activity is followed by the development of, a GNC architecture capable of optimally steering the vehicle towards a targeted landing site under precision and soft-landing constraints. In addition, ATD affects the mission profile at multiple phases and needs to be considered at each design step. Due to complexity and limited computational resources during the preliminary design phase, surrogate models with low response times are required to predict wall heat fluxes along the considered trajectories based on the pressure topology. The complete profile is wrapped up with the Post Mission Disposal strategies to be used by the launchers in order to ensure the compliance with the space debris mitigation guidelines, as well as preliminary reliability aspects of these strategies. The paper provides a preliminary analysis of the discussed topics and their interconnections within the work-frame of ASCenSIon paving the way towards the development of novel cutting-edge technologies for RLVs

    PFAT: Post-flight analysis toolkit

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    A large amount of data, involving various engineering domains, is generated through the different phases of a space mission. In particular, data produced during the operational phases relates directly to flight performance and it requires post-flight analysis in order to be evaluated. Post-Flight Analysis Toolkit (PFAT) is an open-source software, developed in Python under ESA contract, that aims at providing a smooth manipulation and aggregation of such datasets. Extracting figures of merit allows deriving engineering criteria to be used for future flight vehicle design. PFAT contains various modules, which interact which each other through a flexible data container type, which is called Common Data Structure (CDS) and that allows an agnostic data series treatment. The paper provides an overview of the computational capabilities of the tool together with the approach used to connect the different modules into full processing chains. Finally, insights on the verification and validation procedures are provided

    Application of LPV modeling, design and analysis methods to a re-entry vehicle

    No full text
    In this paper the application of linear parameter varying (LPV) modeling, design and analysis methods to a re-entry vehicle is presented The selected atmospheric re-entry benchmaik includes full nonlinear motion, a detailed aerodynamic database (from hypersonic to subsonic), relevant actuator and sensor models and physically-meaningful aerodynamic and parametric uncertainty profiles The results show that (i) LPV controller design methods can solve gain-scheduling problems in a very effective manner, (ii) integral quadratic constraint (IQC) analysis methods can be used very efficiently to accurately interpret the nonlinear time domain simulation results, and, (iii) the use of linear fractional transfoi mation (LFT) and LPV modeling representations are key to a successful analysi

    Prevalence of sarcopenia and associated factors in the healthy older adults of the Peruvian Andes

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    Aim To assess the prevalence of sarcopenia and associated factors in a population of older people living in a rural area of the Peruvian Andes. Materials and methods The study concerned 222 people aged ≥65 years. Sarcopenia was diagnosed on the basis of skeletal muscle mass, measured using bioimpedance analysis, and gait speed, measured with the 4-m walking test, as recommended by the International Working Group on sarcopenia. Self-reported physical activity, the Short Physical Performance Battery, and the Six-Minute Walking Test also contributed information on participants’ physical performance status. Disabilities were investigated by assessing participants’ self-reported difficulties in performing one or more basic or instrumental activities of daily living. Results The prevalence of sarcopenia was 17.6%. Compared with participants without sarcopenia, individuals who were found sarcopenic were significantly older, female and were less frequently farmers, had fewer children, had a worse nutritional status, a significantly lower physical performance, and higher levels of disability in the instrumental activities of daily living. After adjusting for potential confounders, age, female sex, a low body mass index, a self-reported low physical activity level, a worse Six-Minute Walking Test scores, and a low number of children were significantly associated with sarcopenia. Conclusion The prevalence of sarcopenia seems to be quite high among community-dwelling older subjects in the Peruvian Andes. Age, female sex, a low body mass index, little physical activity, a poor Six-Minute Walking Test scores, and a low number of children could be associated with this condition. © 2016 Elsevier Ireland Lt
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