1,720,963 research outputs found
Degenerated BioBentall graft with failing stentless bioprosthesis and dissection of the aortic conduit treated with a bail-out valve in valve procedure: A case report
Full text linkBackground: The Bentall procedure is commonly performed to treat combined aortic valve and ascending aorta disease requiring surgical correction. Although the technique has been shown to provide favourable long-term outcomes, both the valvular prosthesis and the aortic conduit can go through structural degeneration. Increasing use of the biological prosthesis opened to percutaneous treatment of valvular deterioration according to a valve-in-valve (ViV) technique. On the contrary, damages of the tube graft are normally referred to repeated surgical operation. Case summary: In the present case, a patient with a biological Bentall graft was diagnosed with severely deteriorated stentless aortic prosthesis and dissection of the conduit arising from a tube wall tear closely located to the valvular plane. The attempted redo surgery was technically unfeasible because of severe mediastinal adhesions; therefore, a ViV procedure with a balloon expandable transcatheter heart valve was performed in order to contemporarily treat the valve prothesis dysfunction and the aortic tube dissection. No procedure-related complications occurred and subsequent aortic computed tomography angiography showed the sealing of the graft wall false lumen. Discussion: Surgical reintervention remains the treatment of choice for degeneration of a previous Bentall surgery, especially when damages of the aortic conduit exist. Nevertheless, when surgery has to be discarded, ViV can be a reliable option as a bail-out strategy to deal with combined aortic valve dysfunction and tube dissection
Peripheral bare-metal stent implantation for a very-late stenosis of an aortic-left main Cabrol graft: A case report
Full text linkBackground: The surgical ascending aorta repair according to the Cabrol procedure involves the interposition of a prosthetic conduit between the aortic prosthesis and the native coronary ostia. Previous cases of the Cabrol conduit stenosis have been described, most of which presented as acute coronary syndromes due to thrombotic occlusion of the graft. Case summary: We present a case of stable exertional angina due to very-late stenosis of the coronary prosthetic conduit, successfully treated with trans-femoral percutaneous angioplasty and off-label implantation of a balloon-expandable bare-metal stent designed for peripheral artery disease. The multimodality imaging approach gave an essential contribution both to the assessment of the lesion and to the procedural planning. Despite the concerns about long-term results, a peripheral bare-metal stent was preferred over a standard coronary drug-eluting stent due to the remarkable dimension of the Cabrol conduit. Three years after the procedure, the patient is free from angina, and coronary computed tomography showed no significative luminal loss of the stent. Conclusion: Elective angioplasty of a Cabrol graft requires a careful planning through a multimodality stenosis assessment. Conventional coronary stents can be not large enough to ensure adequate apposition to the wide prosthetic conduit and peripheral bare-metal stents may be taken into consideration, at the price of unknown long-term outcomes
How to deal with low-flow low-gradient aortic stenosis and reduced left ventricle ejection fraction: from literature review to tips for clinical practice
Full text linkLow-flow low-gradient aortic stenosis (LFLG AS) with reduced left ventricle ejection fraction (LVEF) is still a diagnostic and therapeutic challenge. The aim of this paper is to review the latest evidences about the assessment of the valvular disease, usually difficult because of the low-flow status, and the therapeutic options. Special emphasis is given to the available diagnostic tools for the characterization of LFLG AS without functional reserve at stress echocardiography and to the factors that clinicians should evaluate to choose between surgical aortic valve repair, transcatheter aortic valve implantation, or medical therapy
TAVR and Dialysis Are a Challenging Combination. A Case Report and Systematic Review of Literature
No full textAdvanced chronic kidney disease (CKD) is associated with poor outcomes in patients undergoing surgical aortic valve replacement, while its prognostic role in transcatheter aortic valve replacement (TAVR) remains unclear. Advanced CKD was defined according to estimated glomerular filtration rate (eGFR): 15–29 mL/min/1.73 m2 (Stage 4—CKD G5), <15 mL/min/1.73 m2 (Stage 5—CKD G5), and CKD G5D if the patient is on hemodialysis. End-stage renal disease (ESRD) increases the risk of developing heart valve disease, mainly aortic stenosis. Nonetheless, ESRD is also known to carry a very high surgical risk, and all the main scoring systems (i.e., STS, Euroscore II) developed to assess prognosis in patients undergoing cardiac surgery take into account this risk factor. Transcatheter aortic valve replacement (TAVR) appears to be a feasible alternative to surgical valve replacement (SAVR), but the initial trials testing this approach systematically excluded patients on dialysis. Several observational studies have been recently conducted among patients with severely impaired renal function and all found a worse prognosis in both the short and long term. We present a case report in which a successful TAVR procedure was performed due to severe symptomatic aortic stenosis in a subject with severe nephropathy. The patient in chronic dialysis developed an early degeneration of aortic bioprosthesis Medtronic CoreValve, which required surgical replacement with a mechanical valve
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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