1,720,965 research outputs found
Retrograde approach for revascularization of a coronary chronic total occlusion with review of literature
No full textNot every coronary occlusion results in an acute coronary syndrome(ACS). The occlusion can develop gradually, allowing collateral circulation formation. If this circulation does not suffice ischaemia in the underperfused myocardial region will causa angina during exercise or progressive symptoms of heart failure. Chronic total conclusion(CTO) of a coronary artery is defined as a complete occlusion(TIMI grade 0 flow) for 3 months or longer. Such occlusions differ from 'recent'(≥3 days) due to an ACS. In this situation, late revascularization has not proven to be superior to optimal medical treatment in the recent TOSCA-2 trial and OAT-trial. Generally, in an ACS there is no or little collateral circulation and after more than 3 days, the regional myocardial viability is lost, which makes a percutaneous coronary intervention (PCI) useless at that time. Recanalization of a CTO can be challenging. First an antegrade approach is used. Depending on the lesion attempted, success rates vary between 50 and 80%. A hard 'proximal fibrous cap' can make it impossible to penetrate and cross the lesion, even with specially designed guide wires. Since 1990, the retrograde approach was developed by Japanese interventionalists to overcome this problem. We present a case of a succesful retrograde recanalization of a CTO of a proximal right coronary artery(RCA) using the reverse CART technique
FFR pressure wire comparative study: piezoresistive versus optical sensor
No full textBackground This study aimed to assess the reliability of pressure derived fractional flow reserve (FFR) measurement and the handling performance of the OptoWire Deux with an optical pressure sensor relative to both the PressureWire X and the Verrata Pressure wire with piezoresistive pressure sensors. Methods This single centre study included 80 patients between October 2016 and May 2017 undergoing a diagnostic coronary angiography. The reliability of FFR measurement measured with the OptoWire Deux relative to the PressureWire X and Verrata Pressure wire was assessed by the presence of drift. Drift was defined as a Pd/Pa measurement different from 1.00 +/- 0.02 when pulled back after a FFR measurement at the location of the initial equalisation. Handling characteristics for all pressure wires were assessed qualitatively with respect to the PressureWire Aeris. Results Ninety-eight measurements in 78 patients were performed; two patients were excluded because the lesion could not be crossed. Very stable and reliable FFR measurements with the optical sensors were registered, relative to the piezoresistive pressure sensors. Drift was found in 11%, 37%, and 33% of the measurements for OptoWire Deux, PressureWire X, and Verrata Pressure wire respectively. The handling performance of the OptoWire Deux was better rated for steerability and torqueability in relation to the standard FFR wire. The handling of the PressureWire X was rated equally good whereas the handling of the Verrata pressure wire was rated inferior in relation to the standard FFR wire. Conclusions In patients undergoing FFR measurement, the OptoWire Deux has a stable and reliable pressure hence FFR measurement with fewer drift events and has good handling characteristics.The authors thank Marcel van ‘t Veer from the Department of Biomedical Engineering of the University of Technology Eindhoven for his statistical support.
Jo Dens receives grants from TopMedical (Distributor of OptoWire Deux)Asahi Intecc co. materials) for teaching courses and proctoring. Joren Maeremans is researcher for the Limburg Clinical Research Program UHasselt-ZOL-Jessa, supported by the foundation Limburg Sterk Merk, Hasselt University, Ziekenhuis Oost-Limburg and Jessa Hospital
Point-of-care heart-type fatty acid binding protein versus high-sensitivity troponin T testing in emergency patients at high risk for acute coronary syndrome
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Subclinical volume overload in stable outpatients with chronic heart failure
No full textObjective The objective of this study was to characterize stable outpatients with subclinical volume overload in chronic heart failure (CHF) by using bioelectrical impedance analysis (BIA) measurements. Methods and results Venous blood sampling and BIA were performed in consecutive CHF patients (n = 58) free from clinical signs of volume overload and treated with oral loop diuretics. Subclinical volume overload was defined as excess extracellular water on BIA. Patients with (n = 34) versus without (n = 24) subclinical volume overload were significantly older (72 +/- 10 versus 65 +/- 9 years; P-value = 0.016), had higher systolic blood pressure (126 +/- 20 versus 114 +/- 17 mmHg; P-value = 0.012), and took angiotensin-converting enzyme inhibitors more often (65% versus 33%; P-value = 0.032). Dyspnoea symptoms were similar among both groups. Subclinical volume overload was associated with low serum albumin (P-value = 0.014) and protein levels (P-value = 0.041). In contrast, serum sodium levels (141 +/- 3 versus 139 +/- 2 mEq/L; P-value = 0.033) but not chloride levels (99 +/- 14 versus 101 +/- 3 mEq/L; P-value = 0.980) were significantly higher in patients with versus without subclinical volume overload, respectively. The former versus latter group also demonstrated lower plasma aldosterone levels [276 (195-475) versus 400 (306-717) ng/L, respectively; P-value = 0.032]. Conclusions Subclinical volume overload assessed by BIA in stable CHF is associated with low serum protein levels, increased serum sodium but not serum chloride, as well as decreased neurohumoral activation.F.V. is supported by a Ph.D. fellowship of the Research Foundation - Flanders (FWO, 11L8214N). F.V., P.N., and W.M. are researchers for the Limburg Clinical Research Program (LCRP) UHasselt-ZOL-Jessa, supported by the foundation Limburg Sterk Merk (LSM), Hasselt University, Ziekenhuis Oost-Limburg and Jessa Hospital. None of the funding sources was involved in the study design, data collection, analysis and interpretation of the data, writing of the report, or the decision to submit the manuscript for publication
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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