1,720,969 research outputs found
Endovascular treatment options for complex abdominal aortic aneurysms
No full textPurpose To report short-term and midterm outcomes of endovascular aneurysm repair (EVAR) of complex aneurysms requiring revascularization of visceral arteries. Materials and Methods Prospective data were collected from patients deemed unsuitable for conventional EVAR and conventional surgery who were treated with different endovascular approaches according to the clinical presentation of the aneurysm. Custom-made fenestrated endovascular aneurysm repair (CM f-EVAR) was used in the elective setting, homemade fenestrated endovascular aneurysm repair (HM f-EVAR) or HM f-EVAR combined with chimney endovascular aneurysm repair (ch-EVAR) was used in the emergent setting in patients with hemodynamic stability, and ch-EVAR was used in unstable cases. The study included 34 consecutive patients. Primary outcomes measured were perioperative mortality and morbidity, renal function impairment (RFI), target vessel patency, and survival at mean follow-up. Results In the CM f-EVAR group (7 of 34 patients; 20.6%), an intraoperative type III endoleak (1 of 7 patients; 14%) sealed spontaneously. At 8.9 months of follow-up, 1 (1 of 7 patients; 14%) death and 1 (1 of 7 patients; 14%) episode of transient RFI were documented. Visceral vessel patency rate was 95.2%. In the HM f-EVAR group (4 of 34 patients; 11.7%) and the combination of HM f-EVAR and ch-EVAR group (3 of 34 patients; 8.8%), no complications were observed at 17.3 months of follow-up. In the ch-EVAR group (20 of 34 patients; 58.8%), visceral patency was 95% at 30.9 months of follow-up. Two cases of transient RFI and 2 cases of permanent RFI were registered (2 of 20 patients; 10%). One asymptomatic renal artery branch occlusion was observed at 11 months of follow-up. No endoleaks were documented. Conclusions Endovascular aneurysm repair techniques including CM f-EVAR, HM f-EVAR or HM f-EVAR in combination with ch-EVAR, and ch-EVAR are valid tools to maintain blood flow in visceral arteries during treatment of complex aortic aneurysms. The proposed interventional protocol based on clinical presentation was feasible in all cases
Aortic aneurysm endovascular treatment with the parallel graft technique from the aortic arch to the iliac axis
No full textBACKGROUND: The chimney technique has been developed for the treatment of complex aortic aneurysms. We analyzed the midterm to long-term outcomes of this approach from a single-center experience.METHODS: From October 2008 to July 2016, 58 patients underwent endovascular aortic aneurysm repair using the chimney technique. Indications for treatment were thoracic aortic aneurysm (TAA) (N.=11), thoracoabdominal aortic aneurysm (TAAA) (N.=2), pararenal aortic aneurysm (PAAA) (N.=15), aortoiliac/isolated hypogastric artery aneurysm (N.=25), type I endoleak after previous TEVAR/EVAR (N.=4), proximal pseudoaneurysm after AAA open repair (N.=1). Elective (82.8%) and emergent (17.2%) procedures were included.RESULTS: The immediate technical success was 100%. Single, double and triple chimneys were performed in 46, 10, and two patients, respectively. Overall, 61 target vessels (three left common carotid arteries, eight left subclavian arteries, three celiac trunks, three superior mesenteric arteries, 19 renal arteries and 25 hypogastric arteries) were involved. Postoperative mortality was 0. No neurologic complications were registered. Primary patency rate of the chimney stent/stent graft was 98.3%. Low-flow type I endoleak was observed in four patients (6.9%). Postoperative chimney graft re-intervention rate was 1.7%. The median follow-up was 32 +/- 20 months (range 3-96 months). Overall estimated survival at 12, 50, and 80 months was 100%, 89% and 44%, respectively. Estimated freedom from endoleak at 1, 12, 24, and 36 months was 96.5%, 95%, 95%, and 93%, respectively. One hypogastric artery stent-graft occluded at the 3rd month of follow-up. No reintervention was performed.CONLUSIONS: Our experience with the chimney technique for aortic aneurysms from the aortic arch to the iliac axis shows promising and durable mid- and long-term results. Endograft oversizing, associated with the chimney graft diameter and length choice remain fundamental to reduce the risk of the most frequent procedure complications: type I endoleak and CG occlusion. The wider use of this technique should be justified in patients considered at high risk for open repair and/or not suitable for the custom-made branched/fenestrated endografts
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
- …
