1,720,976 research outputs found
Assessment of Myocardial Fibrosis Using Advanced Echocardiography in Patients With Systemic Lupus Erythematosus: a Pilot Study
Full text linkBackground: Systemic lupus erythematosus (SLE) is an autoimmune disease, which is characterized by a multi-organ involvement and increased mortality, mainly due to cardiovascular complications. Myocardial fibrosis (MF) is common in SLE, affecting up to 30% of these patients. Cardiac magnetic resonance imaging allows an accurate assessment of myocardial tissue in SLE patients, but it is costly, time consuming, and unfit for patients with coexisting chronic kidney disease. Recent advanced echocardiographic techniques allow an accurate assessment of MF. In particular, speckle tracking echocardiography (STE) is a reproducible technique that provides information about MF by detecting abnormalities in myocardial active deformation. Scar imaging echocardiography with ultrasound multi-pulse scheme (eSCAR) is another novel technique that has been validated for detecting ischemic myocardial scars in patients with prior acute myocardial infarction. Aim: To examine whether STE and eSCAR may detect the presence of subclinical myocardial involvement in patients with SLE. Methods: We consecutively recruited 29 patients (M/F=3/26; age 45±11 years) with established SLE, who had a disease duration of 15±10 years. Their median SLE Disease Activity Index (SLEDAI) score was 2 (0-6). Patients with current cardiac symptoms or prior history of any heart disease were excluded from the study. We also recruited a sample of 32 control individuals, who were comparable for age, sex and traditional cardiovascular risk factors to the cases. All participants underwent a complete echocardiography examination, using both STE and eSCAR. Results: Global longitudinal strain (GLS) was significantly impaired in most myocardial segments in SLE patients than in control subjects, except for the myocardial apical region that was comparable between the two groups. Higher SLEDAI was associated with an impaired GLS-4 chamber (r=0.470, p=0.01) and GLS infero-septal wall (r=0.464, p=0.01). A higher daily dosage of prednisone was also associated with an impaired GLS in the infero-septal myocardial segment (r=0.414, p=0.02). Myocardial scar by eSCAR was observed in 5 (17%) out of 29 SLE patients, mainly in the infero-septal myocardial segment. A significant association was found between the infero-septal GLS and the presence of scar by eSCAR technique (r=0.569, p<0.001). Conclusions: Advanced echocardiography techniques detected the presence of subclinical myocardial dysfunction in SLE patients with no history of cardiac disease compared to controls. An ‘apical sparing’ GLS pattern was also observed in SLE patients, with possible important diagnostic implications. In about one fifth of SLE patients a myocardial scar by eSCAR technique was identified, mainly in the infero-septal segments. Larger prospective studies are certainly needed to confirm these findings and to better elucidate the diagnostic and prognostic significance of advanced echocardiography techniques (including GLS and eSCAR) in patients with SLE
A New Method to Evaluate Atrial Hemodynamic and Quantify Mitral Regurgitation using Cardiovascular Magnetic Resonance: The Pulmonary Venous Flow Approach
No full textPulmonary venous flow (PVF) provides incremental information on left ventricular (LV) diastolic function, and can support the diagnosis of severe mitral regurgitation (MR). The suggestion has been made to combine the left atrial filling volume (LA Fill) and PVF for estimating the mitral regurgitant volume, but echocardiographic PVF evaluation is known to have many limitations. The present case report includes an example of how to assess PVF using cardiovascular magnetic resonance, and a new method is proposed for quantification of the mitral regurgitant volume
Pooled estimates of immediate and late outcome of mitral valve surgery in octogenarians: a meta-analysis and meta-regression
No full textObjective: The authors evaluated the outcome of patients >= 80 years undergoing mitral valve (MV) surgery.Design: Systematic review of the literature and meta-analysis.Setting: None.Participants: None.Interventions: None.Main Results: Twenty-four studies reporting on 5,572 patients 80 years of age who underwent MV surgery were included in this analysis. Pooled proportion of operative mortality was 15.0% (95% confidence interval [CI] 11.9-18.1), stroke was 3.9% (95% Cl 2.6-5.2), and dialysis was 2.7% (95% Cl 0.5-4.9). Early date of study (p = 0.014), increased age (p = 0.006), MV replacement (p = 0.008), procedure other than isolated MV surgery (p = 0.010), MV surgery associated with coronary artery surgery (p = 0.029), aortic cross-clamping time (p < 0.001), and cardiopulmonary bypass time (p < 0.001) were associated significantly with increased operative mortality. MV repair had lower operative mortality compared with MV replacement (7.3% v 14.2%, relative risk 0.573, 95% Cl 0.342-0.962). Random-effects metaregression showed that prolonged aortic cross-clamping time (p = 0.005) was the only determinant of increased operative mortality, even when adjusted (p < 0.001) for date of study (p = 0.004). Operative mortality was significantly higher in studies reporting a mean cross-clamp time >90 minutes (17.0% v 7.4%, p < 0.001). Survival rates at 1, 3, and 5 years were 76.1%, 67.7%, and 56.5%, respectively.Conclusions: MV surgery in patients >= 80 years of age is associated with operative mortality, which has decreased significantly during recent years. Prolonged aortic cross-clamp time is a major determinant of operative mortality. MV repair may achieve better results than MV replacement in the very elderly. Five-year survival of these patients is good and justifies surgical treatment of MV diseases in octogenarians. (C) 2013 Elsevier Inc. All rights reserved
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
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