1,720,963 research outputs found
Upsurge of deep venous thrombosis in patients affected by COVID-19: Preliminary data and possible explanations
Full text linkEndovascular Treatment of a Ruptured Pararenal Abdominal Aortic Aneurysm in a Patient With Coronavirus Disease-2019: Suggestions and Case Report
Full text linkThe aim of this report is to discuss emergent repair for complex aortic diseases in patients affected by novel coronavirus pneumonia (coronavirus disease-2019 [COVID-19]), describing a case of ruptured pararenal aortic aneurysm. An eighty-year-old man with COVID-19 was admitted for ruptured aneurysm of the pararenal aorta and hemorrhagic shock. Endovascular repair was chosen, and a proximal extension of the previous abdominal endograft was performed with parallel stents in the right renal artery and the superior mesenteric artery. Endovascular treatment and early anticoagulation are the key for success for vascular emergencies in patients with COVID-19, despite the risk of late endoleak
Partial Endograft Removal Preserves the Aortic Walls During Delayed Open Conversions of Endovascular Aortic Repair
No full textBackground: Open conversion of endovascular aortic repair (EVAR) is the first-choice treatment in case of endograft failure or high-flow endoleak. However, the traditional technique based on the total removal of the endograft can produce injuries of the aortic walls, with severe consequences on the anastomoses quality. Our aim is to show the advantages of the partial endograft removal on the aortic integrity by reporting a case series including 25 delayed open conversion performed with this technique. Methods: A retrospective study was conducted over the cases of delayed open conversions performed in the last 30 months. Demographics, past medical history, endograft type, causes for conversions, and early and mid-term outcomes were recorded and analyzed in relation with the technique employed (partial vs total endograft removal). Results: Between September 2016 and March 2019, 25 consecutive cases of EVAR failure were converted to open treatment. In all cases, the endografts were resected leaving in place part of the iliac branches, and, whenever possible, also the proximal stent of the main body. Primary technical success was achieved in 100% of cases. Disease-free survival over 18-month median follow-up was 100%. All patients underwent abdominal aortic duplex scan controls as scheduled, with no early or late postoperative complication. No anastomotic aneurysms or any surgery-related complications were observed. Conclusions: Partial endograft removal is a safe and effective technique that could be used to protect the aortic integrity in delayed open conversions of EVAR
Parallel graft techniques for urgent complex aortic diseases: Mid-term results of 12 cases
No full textObjectives: Open repair is still the first choice for thoraco-abdominal and para-renal aortic aneurysms, but surgical treatment is burdened by significant morbidity and mortality, especially in urgent setting. Endovascular treatment by fenestrated or branched endografts is feasible and safe; but in urgent/emergent settings, custom-made endografts are hardly available in due time, and the repair with standard multibranched devices is still debated in cases with complex anatomy. Parallel grafting, on the other hand, which exploits covered stents to preserve patency of the visceral vessels, has been shown as a valuable option and can be performed in urgency, though some concerns still remain regarding its durability and complications. The purpose of this case series is to review the outcomes of all consecutive cases of complex aortic diseases treated with this technique in emergent/urgent setting. Materials and methods: All cases of endovascular aortic repair of thoraco-abdominal and para-thoraco-abdominal performed in urgency or emergency from 2016 to June 2019 were retrospectively reviewed, recording clinical records, operative technique, primary technical success, and long-term outcomes. Each patient was followed-up by computed tomography angiography three months after the procedure and yearly thereafter. Results: Twenty consecutive patients (median age: 68, range: 47–89, male/female ratio: 16:4) affected by para-thoraco-abdominal (12) or thoraco-abdominal (8) were treated in urgent or emergent setting by chimney and/or periscope technique. A total number of 37 visceral vessels were stented (29 renal arteries, 1 polar artery of the kidney, 3 superior mesenteric arteries, and 4 coeliac trunks). Primary technical success was 100%, with one perioperative death. One patient died on post-operative month III for unrelated cause. Two type II endoleaks were detected at the first post-operative imaging studies and were managed conservatively. One type IB endoleak was treated by endovascular repair with a custom-made endograft (overall re-intervention rate: 5%). Over a median 22 months follow-up (range: 4–40, interquartile range: 12 months), all stentgrafts were patent. Conclusion: Parallel graft is a feasible and safe option that should be considered in urgent and emergent treatment of para-thoraco-abdominal and thoraco-abdominal, when fenestrated and branched endografts cannot be used
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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