1,721,026 research outputs found
Trans-Stent FFR Gradient as a Modifiable Integrant in Predicting Long-Term Target Vessel Failure
No full textBackground: Fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) is associated with long-term outcomes. Data relating FFR-based trans-stent gradient (TSG) after PCI to long-term outcomes are sparse. Objectives: The aim of this study was to test whether TSG is associated with adverse events at follow-up after PCI. Methods: Data were gathered from a prospective registry evaluating 501 vessels in 416 patients with median follow-up period of 596 days. Primary endpoints were: 1) target vessel failure (TVF), including target vessel revascularization, and target vessel myocardial infarction after discharge; and 2) major adverse cardiac events (MACE) including TVF, target vessel revascularization, nontarget vessel MI, cardiac death. Results: After PCI, median post-PCI FFR was 0.86 and median TSG was 0.04. TSG >0.04 was associated with increased rates of TVF (8.7% vs 2.9%; P = 0.014) and MACE (17.8% vs 9.2%; P = 0.02). Post-PCI FFR < 0.86 was associated with increased rates of TVF (6.1% vs 2.2%; P = 0.03) and MACE (16.5% vs 10%; P = 0.036). The vessel subgroup with high TSG and low FFR had significantly higher rates of TVF (10.2%; P = 0.02) and MACE (20.1%; P = 0.049) than vessels with: 1) high TSG and high FFR (TVF, 2.9%; MACE, 9.7%); 2) low TSG and low FFR (TVF, 3.8%; MACE, 11.3%); and 3) low TSG high FFR (TVF, 2.2%; MACE, 7.5%). In multivariate analysis, TSG was independently predictive of TVF. Conclusions: Higher TSG was an independent predictor of adverse events, particularly TVF, and identified a subgroup of patients at higher risk for poor outcomes. The combination of high TSG and low FFR showed significantly worse outcomes compared with an “ideal result” (high FFR and low TSG). These data support a recommendation to use TSG during FFR evaluation to determine the functional success of PCI
Subadventitial techniques for chronic total occlusion percutaneous coronary intervention: The concept of “vessel architecture”
No full textDespite improvements in guidewire technologies, the traditional antegrade wire escalation approach to chronic total occlusion (CTO) recanalization is successful in only 60-80% of selected cases. In particular, long, calcified, and tortuous occlusions are less successfully approached with a true-to-true lumen approach. Frequently, the guidewire tracks into the subadventitial space, with no guarantee of distal re-entry into the true lumen. The ability to manage the subadventitial space has been a key step in the tremendous improvement in success rates of contemporary CTO percutaneous coronary intervention (PCI), whether operating antegradely or retrogradely. A modern approach to CTO PCI involves understanding the concept of "vessel architecture," which is based on the distinction between coronary structures (occlusive plaque, comprising the disrupted intima and media, and the outer adventitia) and extravascular space. The vessel architecture represents a safe work environment for guidewire and device manipulation. This review provides an anatomy-based description of the concept of vessel architecture, along with a historical perspective of subadventitial techniques for CTO PCI, and outcome data of CTO PCI utilizing the subadventitial space
Predictors of restenosis following contemporary subintimal tracking and reentry technique: The importance of final TIMI flow grade
No full text
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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