1,721,241 research outputs found
Transcatheter Treatment of Tricuspid and Mitral Regurgitation: Similar Path, Different Stages
No full text: Tricuspid regurgitation (TR) is frequently detected, especially in its secondary form, while primary TR is far less frequent. Similar to mitral regurgitation (MR), primary tricuspid regurgitation should require timely intervention to avoid secondary damage of the RV, which is associated with poor outcome. Current guidelines suggest that secondary TR should be treated at the time of left-sided valve surgery, although a surgical option is rarely offered to high-risk patients with combined heart valve disease. As such, while the transcatheter approach to mitral valve repair/replacement has become a major goal of the transcatheter therapies, the transcatheter tricuspid valve intervention is still at a very early stage. In this review, we provide an overview of the different stages of technical and clinical evolution of transcatheter treatment of patients with TR or MR, highlighting the challenges and the avenues for future research
"Valve in valve" implantation of two self-expandable transcatheter aortic valves in a patient with aortic root aneurysm and massive aortic regurgitation: "a new TAVI option"
No full textCatheter-based treatment of aortic regurgitation (AR) often proves challenging especially due to associated anatomical difficulties. Here, we present a case of CoreValve implantation with a novel use of the valve-in-valve technique to effectively treat severe AR in a patient with repeated cardiac surgery and aneurismatic prosthetic ascending aorta
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
Performance of high conformability vs. high radial force devices in the virtual treatment of TAVI patients with Bicuspid Aortic Valve
No full textObjective: Transcatheter Aortic Valve Implantation (TAVI) is a consolidated procedure showing a low operative risk and excellent long-term outcomes in patients with aortic stenosis. Patients presenting a bicuspid aortic valve (BAV) often require valve replacement due to the highly calcific nature of the aortic leaflets. However, BAV patients have usually been contraindicated for TAVI due to their complex valve anatomy. The aim of this work was to compare the performance of devices featuring high conformability (HC) against those with high radial force (HRF). Methods: Four BAV patients undergoing TAVI were retrospectively selected. The aortic root including the native leaflets and calcifications were reconstructed from pre-operative Computed Tomography scans. In each patient, both HC and HRF devices were virtually implanted using Finite Element Analysis simulations. After implantation, paravalvular orifice area, von Mises stress distribution, root contact area, and device eccentricity were calculated. Results: Simulations showed good agreement with intraoperative imaging. In 3 out of 4 patients, the HRF device resulted in a lower paravalvular area than the HC. Stress distribution was also more homogeneously distributed in the HRF group as compared with the HC group. Despite their lower adaptability, HRF devices showed consistently higher stent-root contact area. Conclusion: HRF devices showed improved results with respect to HC valves after being deployed in BAV anatomies. We hypothesize that the ability to reshape the annulus is the major determinant of success in this subgroup of patients featuring highly calcified leaflets
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
Transcatheter aortic valve implantation in patients younger than 75 years: Guidelines-based patients selection and clinical outcome
No full textBackground: Patients treated by transcatheter aortic valve implantation (TAVI) in all major recent trials are still mostly octogenarians. Aim of this study is to analyze the risk profile and outcome of TAVI patients <75 years.
Methods and results: We retrospectively analyzed 172 patients <75 years with symptomatic severe native AS or degeneration of surgical aortic bioprosthesis treated with TAVI. The level of surgical risk was reassessed according to multiparametric ACC classification (prohibitive in 68 patients, high in 34, intermediate in 70). Mean age was 69.02 ± 6.18 years, mean STS score 5.56 ± 5.21. The majority of them presented one or more clinical or anatomical characteristics favoring TAVI according to ECS guidelines, despite the young age. Vascular access was transfemoral in 76%. According to the VARC-2 definitions, device success was high (90%) in all groups. The early safety was 89%, clinical recovery was slower in prohibitive risk patients. Bleeding events were more frequent in prohibitive and high surgical risk classes. Clinical efficacy at 1 year was overall 83%, and significantly better in intermediate risk patients (p = 0.004). The functional status remained stable over time as well as prostheses performance.
Conclusion: About 40% of patients <75 years were treated by TAVI due to the presence of a prohibitive risk, mainly related to technical impediments. The remaining was referred to TAVI due to an estimated high or intermediate surgical risk driven by STS score, frailty and/or major organ system compromise. Early and mid-term clinical and hemodynamic outcomes were good, in particular in intermediate risk patients
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