545 research outputs found
Transformations of Logic Programs on Infinite Lists
We consider an extension of logic programs, called \omega-programs, that can
be used to define predicates over infinite lists. \omega-programs allow us to
specify properties of the infinite behavior of reactive systems and, in
general, properties of infinite sequences of events. The semantics of
\omega-programs is an extension of the perfect model semantics. We present
variants of the familiar unfold/fold rules which can be used for transforming
\omega-programs. We show that these new rules are correct, that is, their
application preserves the perfect model semantics. Then we outline a general
methodology based on program transformation for verifying properties of
\omega-programs. We demonstrate the power of our transformation-based
verification methodology by proving some properties of Buechi automata and
\omega-regular languages.Comment: 37 pages, including the appendix with proofs. This is an extended
version of a paper published in Theory and Practice of Logic Programming, see
belo
Usefulness of regional right ventricular and right atrial strain for prediction of early and late right ventricular failure following a left ventricular assist device implant: A machine learning approach
Background: Identifying candidates for left ventricular assist device surgery at risk of right ventricular failure remains difficult. The aim was to identify the most accurate predictors of right ventricular failure among clinical, biological, and imaging markers, assessed by agreement of different supervised machine learning algorithms. Methods: Seventy-four patients, referred to HeartWare left ventricular assist device since 2010 in two Italian centers, were recruited. Biomarkers, right ventricular standard, and strain echocardiography, as well as cath-lab measures, were compared among patients who did not develop right ventricular failure (N = 56), those with acute–right ventricular failure (N = 8, 11%) or chronic–right ventricular failure (N = 10, 14%). Logistic regression, penalized logistic regression, linear support vector machines, and naïve Bayes algorithms with leave-one-out validation were used to evaluate the efficiency of any combination of three collected variables in an “all-subsets” approach. Results: Michigan risk score combined with central venous pressure assessed invasively and apical longitudinal systolic strain of the right ventricular–free wall were the most significant predictors of acute–right ventricular failure (maximum receiver operating characteristic–area under the curve = 0.95, 95% confidence interval = 0.91–1.00, by the naïve Bayes), while the right ventricular–free wall systolic strain of the middle segment, right atrial strain (QRS-synced), and tricuspid annular plane systolic excursion were the most significant predictors of Chronic-RVF (receiver operating characteristic–area under the curve = 0.97, 95% confidence interval = 0.91–1.00, according to naïve Bayes). Conclusion: Apical right ventricular strain as well as right atrial strain provides complementary information, both critical to predict acute–right ventricular failure and chronic–right ventricular failure, respectively
The place of vericiguat in the landscape of treatment for heart failure with reduced ejection fraction
The significant morbidity and mortality associated with heart failure with reduced (HFrEF) or preserved ejection fraction (HFpEF) justify the search for novel therapeutic agents. The nitric oxide (NO)–soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway plays an important role in the regulation of cardiovascular function. This pathway is disrupted in HF resulting in decreased protection against myocardial injury. The sGC activator cinaciguat increases cGMP levels by direct, NO-independent activation of sGC, and may be particularly effective in conditions of increased oxidative stress and endothelial dysfunction, and then reduced NO levels, but this comes at the expense of a greater risk of hypotension. Conversely, sGC stimulators (riociguat and vericiguat) enhance sGC sensitivity to endogenous NO, and then exert a more physiological action. The phase 3 VICTORIA trial found that vericiguat is safe and effective in patients with HFrEF and recent HF decompensation. Therefore, adding vericiguat may be considered in individual patients with HFrEF, particularly those at higher risk of HF hospitalization; the efficacy of the sacubitril/valsartan-vericiguat combination in HFrEF is currently unknown
Use of echocardiography in the management of congestive heart failure in the community
AbstractObjectives. We evaluated the use and the impact of echocardiography in patients receiving an initial diagnosis of congestive heart failure in Olmsted County, Minnesota, in 1991.Background. The American College of Cardiology/American Heart Association clinical practice guidelines recommend echocardiography in all patients with suspected congestive heart failure. No data are available on use and impact of echocardiography in management of congestive heart failure in a community.Methods. The medical records linkage system of the Rochester Epidemiology Project was used to identify all 216 patients who satisfied the Framingham criteria for congestive heart failure. Of these, 137 (63%) underwent echocardiography within 3 weeks before or after the episode of congestive heart failure (Echo group), and the other 79 patients constitute the No-Echo group.Results. The No-Echo group patients were older (p = 0.022), were more likely to be female (p = 0.072), had milder symptoms (p = 0.001) and were less often hospitalized at diagnosis (p = 0.001). Fewer patients in the No-Echo group were treated with angiotensin-converting enzyme inhibitors (p = 0.001). Advanced age (≥80 years), lower New York Heart Association functional class, absence of a fourth heart sound on examination, absence of cardiomegaly or signs of congestive heart failure on chest radiography and absence of known valve disease were independently related to the decision not to obtain an echocardiogram. Survival after adjustment for age, functional class and gender was lower in the No-Echo group than the Echo group (risk ratio = 0.607, p = 0.017).Conclusions. The underuse of echocardiography appears to be associated with poorer survival and underuse of angiotensin-converting enzyme inhibitor therapy
How cardiologists can manage excess body weight and related cardiovascular risk. An expert opinion
Obesity is an important independent cardiovascular (CV) risk factor and a chronic inflammatory disease related to the development of insulin resistance, type 2 diabetes, dyslipidaemia, coronary artery disease, hypertension, heart failure, atrial fibrillation and obstructive sleep apnoea. Body Mass Index (BMI) values >27 kg/m2 are associated with an exponential increase in the risk for Major Adverse Cardiac Events (MACE). On the other hand, weight reduction can significantly reduce metabolic, CV and oncological risk. Orlistat, bupropion/naltrexone, liraglutide and semaglutide, combined with lifestyle changes, have proven to be effective in weight loss; the last two have been tested in randomized clinical trials (RCTs) with CV outcomes only in diabetic patients, and not in obese patients. To fill a fundamental gap of knowledge, the SELECT trial on patients with obesity and CV disease treated with semaglutide is ongoing, aiming at MACE as the primary endpoint. The battle against the social and clinical stigma towards obesity must be counteracted by promoting an awareness that elevates obesity to a complex chronic disease. Several actions should be implemented to improve the management of obesity, and cardiologists have a key role for achieving a global approach to patients with excess weight also through the correct implementation of available treatment strategies
Fatty Hepatocytes Induce Skeletal Muscle Atrophy In Vitro: A New 3D Platform to Study the Protective Effect of Albumin in Non-Alcoholic Fatty Liver
The liver neutralizes endogenous and exogenous toxins and metabolites, being metabolically interconnected with many organs. Numerous clinical and experimental studies show a strong association between Non-alcoholic fatty liver disease (NAFLD) and loss of skeletal muscle mass known as sarcopenia. Liver transplantation solves the hepatic-related insufficiencies, but it is unable to revert sarcopenia. Knowing the mechanism(s) by which different organs communicate with each other is crucial to improve the drug development that still relies on the two-dimensional models. However, those models fail to mimic the pathological features of the disease. Here, both liver and skeletal muscle cells were encapsulated in gelatin methacryloyl and carboxymethylcellulose to recreate the disease’s phenotype in vitro. The 3D hepatocytes were challenged with non-esterified fatty acids (NEFAs) inducing features of Non-alcoholic fatty liver (NAFL) such as lipid accumulation, metabolic activity impairment and apoptosis. The 3D skeletal muscle tissues incubated with supernatant from fatty hepatocytes displayed loss of maturation and atrophy. This study demonstrates the connection between the liver and the skeletal muscle in NAFL, narrowing down the players for potential treatments. The tool herein presented was employed as a customizable 3D in vitro platform to assess the protective effect of albumin on both hepatocytes and myotubes
Sacubitril/valsartan reduces serum uric acid concentration, an independent predictor of adverse outcomes in PARADIGM-HF
Aims:
Elevated serum uric acid concentration (SUA) has been associated with an increased risk of cardiovascular disease, but this may be due to unmeasured confounders. We examined the association between SUA and outcomes as well as the effect of sacubitril/valsartan on SUA in patients with heart failure with reduced ejection fraction (HFrEF) in PARADIGM-HF.
Methods and results:
The association between SUA and the primary composite outcome of cardiovascular death or heart failure (HF) hospitalization, its components, and all-cause mortality was examined using Cox regression analyses among 8213 patients using quintiles (Q1–Q5) of SUA adjusted for baseline prognostic variables including estimated glomerular filtration rate (eGFR), diuretic dose, and log N-terminal pro-brain natriuretic peptide. Change in SUA from baseline over 12 months was also evaluated in each treatment group. Patients in Q5 (SUA ≥8.6 mg/dL) compared with Q1 (<5.4 mg/dL) were younger (62.8 vs. 64.2 years), more often male (88.7% vs. 63.1%), had lower systolic blood pressure (119 vs. 123 mmHg), lower eGFR (57.4 vs. 76.6 mL/min/1.73 m2), and greater diuretic use. Higher SUA was associated with a higher risk of the primary outcome (adjusted hazard ratios) Q5 vs. Q1 = 1.28 [95% confidence intervals (1.09–1.50), P = 0.003], cardiovascular death [1.44 (1.11–1.77), P = 0.001], HF hospitalization [1.37 (1.11–1.70), P = 0.004], and all-cause mortality [1.36 (1.13–1.64), P = 0.001]. Compared with enalapril, sacubitril/valsartan reduced SUA by 0.24 (0.17–0.32) mg/dL over 12 months (P < 0.0001). Sacubitril/valsartan improved outcomes, irrespective of SUA concentration.
Conclusion:
Serum uric acid concentration was an independent predictor of worse outcomes after multivariable adjustment in patients with HFrEF. Compared with enalapril, sacubitril/valsartan reduced SUA and improved outcomes irrespective of SUA
The use of pulse-compression thermography for detecting defects in paintings
Interest in the conservation of paintings grows year by year. Their periodic inspection is essential for their conservation over the time. Thermographic non-destructive inspection is one technique useful for paintings, but it is essential to be able to detect buried defects while minimising the level of thermal stimulus. This paper describes a pulse-compression infrared thermography technique whereby defect detection is optimized while minimising the rise in temperature. To accomplish this task, LED lamps driven by a coded waveform based on a linear frequency modulated chirp signal have been used on paintings on both a wooden panel and a canvas layer. These specimens contained artificially fabricated defects. Although the physical condition of each painting was different, the experimental results show that the proposed signal processing procedure is able to detect defects using a low temperature contrast
Monitoring of biomarkers in heart failure.
The role of biomarkers is increasingly recognized in heart failure (HF) management, for diagnosis, prognostication, and screening of high-risk patients. Beyond natriuretic peptides and troponins, the utility of novel, emerging biomarkers is less established. This document reflects the key points of a Heart Failure Association of the European Society of Cardiology (ESC) consensus meeting on biomarker monitoring in HF
- …