1,721,020 research outputs found
Managing challenging patients with venous thromboembolism: A practical, case-based approach
No full textThe management of patients with venous thromboembolism (VTE) is a common clinical scenario that, for the most part, involves well-established, evidence-based treatment pathways. However, important unanswered clinical questions remain that are the focus of ongoing research. The aim of this narrative review is to provide a practical, case-based approach to the following clinical scenarios in which therapeutic management pathways are less well established: How long to administer anticoagulation to patients with a first unprovoked VTE? How to manage complex patients with cancer-associated VTE? When and how to treat patients with splanchnic vein thrombosis? When to use thrombolytic therapy for deep vein thrombosis
Factors that influence heparin levels in patients with venous thromboembolism treated with subcutaneous weight-adjusted unfractionated heparin and low-molecular weight heparin, and whether heparin levels are associated with bleeding and recurrent venous thromboembolic events
Full text link1. Abstract
1.1. Background It is uncertain whether 1) patient’s characteristics (e.g., age, weight, height, and sex) influence anti-Xa heparin levels (hereafter referred to as "heparin levels"), or 2) if heparin levels influence recurrent venous thromboembolism (VTE) or bleeding events, in patients with acute VTE treated with weight-adjusted therapeutic-dose subcutaneous (SC) unfractionated heparin (UFH) or SC low-molecular weight heparin (LMWH). To determine if either association exist, we analyzed data from the Fixed-Dose Heparin (FIDO) study, in which patients were randomized to either SC UFH or SC LMWH, each given in fixed weight-adjusted doses and overlapped with 3 month of warfarin therapy for treatment of acute VTE.
1.2. Methods During the original study, 708 patients were asked to participate in a sub-study that would measure peak heparin levels while they were treated with heparin. 408 patients provided blood samples and met the eligibility criteria for the analyses in this thesis. Linear regression was used to examine the influence of patients’ baseline characteristics (e.g., age, weight, height, body mass index [BMI], sex) on heparin levels. The influence of other factors (e.g., type of heparin [UFH or LMWH]) on heparin levels was also assessed. Logistic regression was used to examine the association of heparin levels with the outcomes of 1) recurrent VTE during 3 months of follow up, and 2) bleeding events in the first 10 days of follow up.
1.3. Results: Mean heparin levels were 0.695 in patients treated with UFH, 0.698 in those treated with dalteparin and 1.034 in those treated with enoxaparin (p<0.001; R2=0.08 for variability accounted for by type of heparin). In a univariable analysis, heparin levels increase by 0.04 IU/ml (95% CI 0.02-0.07; p=0.001; R2=0.03) for every 10-kg increment in weight, by 0.02 IU/ml (95% CI 0.01-0.03; p<0.001; R2=0.04) for each unit of BMI, and by 0.03 IU/ml (95% CI 0.01-0.05; p=0.001; R2=0.03) for every 10 mol/l increment in creatinine. In a multivariable analysis, weight, BMI, and creatinine still influenced heparin levels, after adjusting for type of heparin and timing of blood sample withdrawal. Although heparin levels increased with weight, the magnitude was not large enough to suggest altering the current weight-based dosing method for LMWH. Other baseline factors such as age, height, type of VTE, creatinine clearance and hospitalization status did not influence heparin levels in patients treated with UFH or LMWH. In a univariable analysis, when heparin levels were treated as a continuous variable, higher heparin levels were associated with a lower risk of recurrent VTE at 90-days in patients treated with LMWH (OR 0.04, 95% CI 0.003-0.550, for each 1.0 IU/ml increase in heparin levels), but not in patients treated with UFH (OR 1.46, 95% CI 0.37-5.58, for each 1.0 IU/ml increase in heparin levels). In addition, higher heparin levels were associated with a higher risk of bleeding at 10-days in patients treated with UFH (OR 3.32, 95% CI 1.30-8.46 for each 1 IU/ml increase in heparin levels) but not in patients treated with LMWH (OR 3.77, 95% CI 0.42-33.92, for each 1.0 IU/ml increase in heparin levels). In a multivariable analysis, the association of heparin levels with VTE at 90-days in patients receiving LMWH (lower VTE events) and with bleeding events at 10-days in patients receiving UFH (higher bleeding events) persisted after adjusting for antiplatelet use at baseline and diagnosis of cancer at baseline. When heparin levels were treated as a dichotomous variable (subtherapeutic vs. non-subtherapeutic levels and supratherapeutic vs. non-supratherapeutic levels), the proportion of patient with recurrent VTE was significantly higher in patients with subtherapeutic levels compared with non-subtherapeutic levels in patients receiving LMWH (8.6% vs. 1.3%, p = 0.01). No significant difference was found in the proportion of patients with subtherapeutic levels and non-subtherapeutic levels in patients receiving UFH (0% vs. 3.4%, χ2=0.15, p= 0.70). The test of interaction supported the decision to analyze LMWH and UFH groups separately (p=0.02). Finally, the proportion of patient with bleeding was higher in patients with supratherapeutic compared with non-supratherapeutic heparin levels (6.5% vs. 1.5%, χ2=7.65, p=0.01). The test of interaction did not support the decision to analyze LMWH and UFH groups separately (p=0.13).
1.4. Conclusions Although it was possible to identify factors that were associated with heparin levels in patients who had been treated with weight-adjusted UFH or LMWH, none of these associations were strong enough to suggest that variables other than weight should influence SC heparin dosing. Subtherapeutic heparin levels were associated with a higher risk of recurrent VTE in patients treated with LWMH but not UFH, and supratherapeutic heparin levels were associated with a higher risk of bleeding in patients treated with UFH but not LMWH. Indirectly, these findings suggest that adjusting UFH or LMWH dose in response to heparin levels might improve clinical outcomes.ThesisMaster of Science (MSc
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
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
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
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
Long-term treatment for venous thromboembolism.
No full textInternational audienceAnticoagulation is the corner stone of therapy for venous thromboembolism. The optimal duration of this therapy depends on the balance between the risk of recurrent thrombosis if anticoagulants are stopped, and the risk of bleeding if patients remain on treatment. The risk of recurrence is low if thrombosis was precipitated by a major reversible risk factor such as surgery. Patients with idiopathic thrombosis (no apparent risk factor) and those with persistent risk factors (eg, cancer), have a high risk of recurrence. Some hereditary (eg, protein C, protein S or antithrombin deficiency; homozygous factor V Leiden) and acquired (eg, antiphospholipid antibodies) thrombophilic states are also risk factors for recurrence. Three months of anticoagulation is recommended when the risk of recurrence is low, whereas the duration of therapy should be extended to 6 months or longer when this risk is high, depending on the balance between the risk of recurrence and the risk of bleeding in each individual patient. Heparin preparations, at doses intermediate to those used for the acute treatment of venous thromboembolism and for primary prophylaxis, are an alternative to oral anticoagulants during the maintenance phase of treatment
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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