1,721,061 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Invasive haemodynamic characteristics and clinical outcomes of patients presenting with symptomatic severe aortic valve stenosis undergoing transcatheter aortic valve implantation
No full textThe present thesis is comprised of an introduction followed by eight chapters. The introduction gives an overview of the transcatheter aortic valve implantation (TAVI) procedure and details the patient selection process. Chapter 1 reviews the methods of determining aortic stenosis (AS) heamodynamic severity and the pros and cons of using transthoracic echocardiography versus an invasive evaluation. Severe AS may be divided into three subtypes, namely, 1) high gradient AS, 2) “paradoxical” low-flow, low-gradient severe AS, and 3) low ejection fraction, low-gradient (LEF-LG) severe AS. Chapter 2 assesses the clinical outcomes of patients undergoing TAVI according to this new classification system. Chapter 3 further explores the flow-gradient classification of severe AS as proposed by Dumesnil et al. The majority of patients presenting with symptomatic severe AS have concomitant coronary artery disease (CAD), and the appropriate management of this condi-tion is an important consideration in the overall management of patients presenting with sympto-matic severe AS. Chapter 4 provides a comprehensive overview of the management of concomi-tant CAD among patients presenting with symptomatic severe AS. Chapter 5 and chapter 6 deal with the high-risk subset of patients presenting with LEF-LG severe AS. Patients presenting with the latter condition have a high prevalence of concomitant CAD, and chapter 5 attempts to address the optimal strategy for managing these patients. Patients presenting with LEF-LG severe AS also have a high prevalence of concomitant moderate to severe mitral regurgitation (MR) and chapter 6 assesses the effect of MR on clinical outcomes after TAVI. A new classification for pulmonary hy-pertension was recently proposed and chapter 7 investigates whether this system may be useful for further risk stratification of patients undergoing TAVI. Finally, chapter 8 investigates the impact of B-type natriuretic peptide on short term clinical outcomes after TAVI
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Twelve-month follow-up results from the SIRONA 2 clinical trial
No full textAimsIn the SIRONA 2 trial, the safety and efficacy of pulmonary artery (PA) pressure (PAP)-guided heart failure (HF) management using a novel PAP sensor were assessed at 30 and 90 days, respectively, and both endpoints were met. The current study examines the prespecified secondary endpoints of safety and accuracy of the PA sensor along with HF hospitalizations and mortality, HF symptoms, functional capacity, quality of life, and patient compliance through 12 months. Methods and resultsSIRONA 2 is a prospective, multi-centre, open-label, single-arm trial evaluating the Cordella (TM) PA Sensor System in 70 patients with New York Heart Association (NYHA) functional class III HF with a prior HF hospitalization and/or increase of N-terminal pro-brain natriuretic peptide within 12 months of enrolment. Sensor accuracy was assessed and compared with measurements obtained by standard right heart catheterization (RHC). Safety was defined as freedom from prespecified adverse events associated with use of the Cordella PA Sensor System and was assessed in all patients who entered the cath lab for PA sensor implant. HF hospitalizations and mortality, HF symptoms, functional capacity, quality of life, and patient compliance were also assessed. At 12 months, there was good agreement between the Cordella PA Sensor System and RHC, with the average difference for mean PAP being 2.9 +/- 7.3 mmHg. The device safety profile was excellent with 98.4% freedom from device/system-related complications. There were no pressure sensor failures. HF hospitalizations and mortality were low with a rate of 0.33 event per patient year. Symptoms as assessed by NYHA (P < 0.0001) and functional capacity as measured by 6 min walk test (P = 0.02) were significantly improved. Patients' adherence to daily transmissions of PAP and vital signs measurements was 95%. ConclusionsLong-term follow-up of the SIRONA 2 trial supports the safety and accuracy of the Cordella PA Sensor System in enabling comprehensive HF management in NYHA class III HF patients.Endotronix In
Feasibility of Continuous Noninvasive Pulmonary Artery Pressure Monitoring via the Cordella Implantable Pulmonary Artery Sensor
No full textAlthough cardiopulmonary exercise testing (CPET) is considered the gold standard assessment of functional capacity and prognosis in heart failure (HF) patients, pulmonary hemodynamics can be measured during incremental exercise at invasive right heart catheterization or noninvasively at exercise echocar-diography to assess the physiologic responses to exercise and help guide patient management. 1,2 The Cordella PA sensor (Endotronix Inc) transmits pulmonary artery pressures (PAPs) from HF patients to their clinical team, and a harness was developed to allow for hands-free continuous PAP readings. The results of a feasibility study of HF patients who underwent Cordella PA sensor implant and subsequent 6-minute walk test (6MWT) with continuous PAP readings are reported here. The SIRONA 2 clinical trial has been previously described. 3 The study was undertaken in accordance with the Declaration of Helsinki and approved by the relevant competent authorities and independent ethics committees. All patients provided written informed consent. At a follow-up visit, each participant underwent the Cordella 6MWT protocol. To begin, patients assumed a seated position. The reader was then activated to begin recording continuous PAP, a timer was started, and the patients rested for 5 minutes. Then, blood pressure (BP), oxygen saturation (SpO 2), and the Borg Rating and Perceived Exertion (RPE) scale were assessed. Patients then stood for 1 minute before performing the 6MWT. Following the 6MWT, patients were asked to sit, and BP, SpO 2 , and Borg RPE were assessed. Following at least 5 minutes of sitting, BP, SpO 2 , and Borg RPE were assessed again, and the timer and reader were stopped. Continuous PAP waveform processing was performed in LabVIEW Runtime version 2019 (National Instruments) (Figure 1A). Heart rate was derived from the PAP waveform. The 10-second periods before each minute in the test were averaged for both PAP and heart rate for the purposes of plotting and comparing timepoints within the test (Figure 1B). Data are reported as median with IQR. Changes in parameters were compared using repeated-measures Student's t-tests with a significance threshold of P < 0.05. Twelve subjects underwent the Cordella 6MWT with successful continuous PAP measurement. At baseline, the median age was 71.0 years (Q1-Q3: 68.5-74.8 years), 7 (58.3%) were male, and they had a median 6MWT of 370.0 m (Q1-Q3: 321.5-403.5 m). All had NYHA functional class III at baseline but had progressed to NYHA functional class II at the time of the 6MWT. Patients underwent the 6MWT protocol a median of 552 days (Q1-Q3: 379-1,054 days) from implant. The median distance walked was 336.0 m (Q1-Q3: 292.3-389.8 m). Measurement of all hemody-namic variables was feasible in all subjects during the entire study protocol, and PAP was continuously recorded for a minimum of 17 minutes in all cases. PA pressures and heart rate increased significantly during the 6MWT (systolic: þ29.2 mm Hg [Q1-Q3: 23.1-34.7 mm Hg]; diastolic: þ13.2 mm Hg [Q1-Q3: 9.9-16.4 mm Hg]; mean: þ21.1 mm Hg [Q1-Q3: 9.9-16.4 mm Hg]; heart rate: þ24.0 beats/min [Q1-Q3: 18.0-36.0 beats/min]; all values of P < 0.05) and What is the clinical question being addressed? Whether continuous, noninvasive PAP measurement during ambulatory exercise is feasible using an implantable PA sensor. What is the main finding? Continuous, noninvasive PAP measurement using the Cordella PA Sensor system is feasible in HF patients during exercise
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Advanced telehealth for chronic heart failure management
No full textHeart Failure (HF), a chronic and progressive clinical syndrome characterized by symptoms like dyspnoea, oedema, and fatigue, affects millions worldwide, leading to high rates of hospitalization and mortality. Traditional management relies on in-person diagnostics and hospital-based care, often resulting in delayed intervention and increased burden on healthcare systems. Remote monitoring (RM) via telehealth represents a pivotal shift towards proactive HF management, allowing for continuous, real-time data collection, early detection of decompensation, and prompt interventions. This thesis explores an innovative approach to HF management through the design, development and validation of a novel implantable sensor for central venous pressure (CVP) monitoring in the inferior vena cava (IVC), and compares its clinical relevance to the existing pulmonary artery pressure (PAP) sensors currently used in clinical practice.
Recent clinical trials utilizing PAP monitoring technologies (e.g., CardioMEMSTM, Abbott, Atlanta, GA, United States, and CordellaTM, Endotronix Inc., Lisle, IL, United States) demonstrate the clinical benefits of RM for HF, including reduced hospitalizations and optimized therapy for high-risk patients with multiple comorbidities. However, these technologies are constrained by their invasiveness, requiring right heart catheterizations, extended procedure times, prolonged exposure to contrast media, and complex target anatomy, which limits their suitability for many patients. The IVC presents a promising alternative site for assessing congestive HF, using CVP as a potential haemodynamic marker in HF monitoring. Unlike PAP, however, the full diagnostic potential of CVP remains underexplored. This thesis addresses this gap by assessing the clinical relevance of CVP in HF diagnostics, designing an anchoring system for an implantable CVP sensor optimized for IVC placement, and evaluating its feasibility within a preclinical context.
A literature review on existing RM technologies and telehealth platforms established the need for improved diagnostic capabilities for HF patients, especially for those ineligible for PAP monitoring. Key research questions included the clinical significance of CVP, benefits and limitations of IVC implantation, and practical challenges in implementing solutions that combine invasive and non-invasive monitoring. Based on these questions, research objectives focused on CVP diagnostics, sensor design, development, and validation, as well as the implementation of a telehealth platform combining both RM approaches.
The first part of this thesis investigated the design and development of a CVP sensor to address unique anatomical challenges in the IVC. A novel anchoring system was engineered to ensure stable sensor positioning, prevent migration, and maintain accurate CVP measurements. Bench testing using custom-made silicone IVC model evaluated device performance under physiological conditions. Computational fluid dynamics (CFD) modelling assessed the implant’s impact on blood flow, validating safety and feasibility for in-vivo testing. An animal study involving simultaneous CVP and PAP measurements established baseline data for haemodynamic trends, with results confirming the sensor’s accuracy and reliability. This study provided foundational data to support the potential of CVP as a valuable marker for HF management and demonstrated a safe, efficient IVC implantation technique.
The second part of this thesis investigated a clinical, observational telehealth study assessing outcomes in three patient cohorts over 12 months: a non-invasive group using commercial devices and a tablet for vital sign monitoring (Croga); an invasive cohort using PAP monitoring along with the same devices and a tablet; and a Control group under routine standard of care. Findings indicated that the Implant group demonstrated the highest compliance (99%) and significant improvements in functional status (P<0.001), aligning with previous studies using similar technology for PAP monitoring. The telehealth intervention successfully reduced HF hospitalizations and improved medication management, underscoring the benefits of remote monitoring in HF patients. Despite these successes, limitations such as small sample size and uneven NYHA class distribution suggests a need for larger-scale studies to validate these findings both clinically and statistically.
This thesis advances HF management by introducing a CVP sensor with potential to address gaps in current RM strategies and by establishing a telehealth platform that accommodates diverse patient needs. The novel integration of CVP and PAP monitoring expands clinical insights into HF progression and treatment efficacy. Future research should focus on refining the bench methods by redesigning sensor technologies and anchoring mechanisms to optimize their placement and use within the cardiovascular system, enhance bedside monitoring by expanding the scope of RM for diverse HF populations, while assessing their long-term relevance and efficacy. The results of this thesis support a more individualised and proactive approach to HF management, offering a significant step forward in the adoption and maintenance of telehealth solutions tailored to the complex and evolving needs of HF patients
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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