1,721,049 research outputs found
Outcomes of aortic valve repair according to valve morphology and surgical techniques
Get PDFOBJECTIVES: The aim of this study was to assess the impact of aortic valve morphology and different surgical aortic valve repair techni-
ques on long-term clinical outcomes.
METHODS: Between February 2003 and May 2010, 216 patients with aortic insufficiency underwent aortic valve repair in our institu- tion. Ages ranged between 26 and 82 years (mean 53 ± 15 years). Aortic valve dysfunctions, according to functional classification, were: type I in 55 patients (25.5%), type II in 126 (58.3%) and type III in 35 (16.2%). Sixty-six patients (27.7%) had a bicuspid valve. Aortic valve repair techniques included sub-commissural plasty in 138 patients, plication in 84, free-edge reinforcement in 80, resection of raphe plus re-suturing in 40 and the chordae technique in 52. Concomitant surgical procedures were CABG in 22 (10%) patients, mitral valve repair in 12 (5.5%), aortic valve-sparing re-implantation in 78 (36%) and ascending aorta replacement in 69 (32%). Mean follow- up was 42 ± 16 months and was 100% complete.
RESULTS: There were six early deaths (2.7%). Overall late survival was 91.5% (18 late deaths). There were 15 (6.9%) late cardiac-related deaths. NYHA functional class was ≤II in all patients. At follow-up, 28 (14.5%) patients had recurrent aortic insufficiency ≥ grade II. The freedom from valve-related events was significantly different between bicuspid and tricuspid valve implantation (P < 0.01), between type I + II and type III (P < 0.001) dysfunction and between the chordae technique and plication, compared to free-edge reinforcement (P < 0.01). Statistically-significant differences were found between patients who underwent aortic valve repair plus root re-implantation, compared to those who underwent isolated aortic valve repair (P = 0.02).
CONCLUSIONS: aortic valve repair including aortic annulus stabilization is a safe surgical option with either tricuspid or bicuspid valves; even more so if associated with root re-implantation. Patients with calcified bicuspid valves have poor results
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Surgical management of moderate ischemic mitral valve regurgitation: Where do we stand?
No full textIschemic mitral regurgitation (IMR) represents a common complication after myocardial infarction. The valve is anatomically normal and the incompetence is the result of papillary muscles displacement and annular dilatation, causing leaflets tethering. Functionally the leaflets present a restricted systolic motion due to tethering forces that displaces the coaptation surface toward the left ventricle apex. The patients present poor left ventricular function at the time of surgery and the severity of the mitral regurgitation increases the risk of mortality. Currently there is general agreement to treat surgically severe IMR nevertheless strong evidences for patient with moderate insufficiency remains poor and proper treatment debated. The most effective surgical approach for the treatment of IMR remains debated. Some authors demonstrated that coronary artery bypass graft (CABG) alone is beneficial in patients with IMR. Conversely, in most patients, moderate IMR will persist or worsen after CABG alone which translate in higher long-term mortality as a function of residual mitral regurgitation severity. A probable reason for this unclear surgical management of functional MR is due to the contemporary suboptimal results of reparative techniques. The standard surgical treatment of chronic IMR is CABG associated with undersized annuloplasty using complete ring. Though, the recurrence of mitral regurgitation remains high (> 30%) because of continous left ventricle remodeling. To get better long term results, in the last decade, several subvalvular procedures in adjunct to mitral anuloplasty have been developed. Among them, surgical papillary muscle relocation represents the most appreciated option capable to restore normal left ventricle geometry. In the next future new preoperative predictors of increased mitral regurgitation recurrence are certainly needed to find an individual time period of treatment in each patient with moderate IMR
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
New Technique for Aortic Valve Functional Annulus Reshaping Using a Handmade Prosthetic Ring
Get PDFBackground. Despite a wide development in aortic
leaflets repair techniques, aortic valve annuloplastic procedures
are still poorly investigated. We present our
aortic valve annuloplastic system consisting of a handmade
prosthetic ring with 2 components for reshaping
the aortic annulus and sinotubular junction (STJ) and
illustrates our surgical approach and clinical results.
Methods. Since February 2003, 45 patients with aortic
valve regurgitation underwent aortic annuloplasty using
the new ring. Mean patient age was 58 16 years (range,
46 to 76 years). The ring has 2 components: a circular ring
used to undersize the circumference of the aortoventricular
junction and 3-crown-like shape ring used for STJ
remodeling. The circular ring was sutured into the left
ventricular outflow tract in the aortic subvalvular position
and the STJ ring was sutured from the outside of the
aortic root just at the level of the STJ. The 3 vertical bands
of the STJ ring were fixed to the underlying circular ring
to stabilize the continuity between the STJ and nadir of
the aortic valve.
Results. No in-hospital death occurred. Two patients
had residual trivial aortic valve regurgitation postoperatively,
and 3 patients required treatment for residual
aortic regurgitation (more than mild). Mean length of the
coaptation surface was 10 2 mm. The mean clinical
follow-up (100% complete) was 22 16 months. All
patients were free from cardiac and valve-related events,
and no complications due to ring implantation occurred.
Conclusions. This ring reshapes the functional aortic
annulus and stabilizes all components of the native
aortic valve stent to improve long-term results of valve
repair
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