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Insertion/deletion polymorphism of the Angiotensin I-Converting Enzyme gene and risk of restenosis after directional coronary atherectomy followed by stent implantation
No full textBackground: The renin-angiotensin system is involved in neointimal hyperplasia in response to arterial injury. The insertion/deletion (I/D) polymorfism of the Angiotensin Converting Enzyme (ACE)gene largely controls plasma levels. It has been reported that D allele is associated with increased risk of restenosis after coronary stenting. However, plaque remodelling may also be an important determinant of restenosis after stent implantation. Debulking the lesion before stent implantation by means of directional coronary atherectomy (DCA) reduce the influence of plaque remodelling leaving neointimal hyperplasia as the major mechanism of restenosis. Therefore, DCA followed by stent implantation represents an ideal model to investigate the relationship between ACE I/D polymorphism and restenosis.
Methods: We prospectively evaluated 113 consecutive patients (102 male, 90%; mean age 57±9 yrs) who underwent seccessful (residual stenosis 75% and <100% of coronary stenosis with a lesion length <15 mm. Genomic DNA was prepared from peripheral blood leukocytes and analysed by means of PCR amplification. Baseline, post-DCA, post-stent and follow-up angiograms, performed after 6-12 months, were quantitatively analysed. Subjects were divided into three groups, according to the genotype (DD, ID, II).
Results: The observed genotype distribution was in agreement with the expected Hardy-Weinberg proportion. No significant differences were observed among the three groups in terms of acute gain (DD=2.27±0.49 mm;ID=2.16±0.57 mm; 11=2.24±0.38 mm; p=ns), late loss (DD=0.73±0.73 mm; ID=0.9±0.72 mm; 11=0.63±0.65 mm; p=ns), net gain (DD=1.54±0.72 mm; ID=1.25±0.78 mm; 11=1.62±0.78 mm; p=ns) or percent of patients developing angiographic restenosis (DD=8.8%; ID=7.2%; 11=9.8%).
Conclusion: Our data indicate that ACE I/D gene polymorphism is not associated with the risk of developing restenosis in a model of plaque debulking plus stent implantation
Adjunctive stent implantation following directional coronary atherectomy in patients with coronary artery disease
No full textObjectives. This prospective case control study evaluated the acute and long-term results of stent implantation preceded by debulking of the plaque by means of directional coronary atherectomy.
Background. In comparison with balloon angioplasty, intracoronary stenting produces a larger luminal diameter, maintains artery patency and reduces the incidence of restenosis. Optimal stent deployment is a pivotal factor for achieving the best results, but the bulk of the atherosclerotic plaque opposes stent expansion and may limit the success of the procedure. Debulking of the plaque may provide a better milieu for optimal stent deployment.
Methods. Directional coronary atherectomy followed by a single Palmaz-Schatz stent implantation was attempted in 100 patients. The successes, complications and angiographic results of the combined procedure were evaluated both acutely and during follow up. Matched patients undergoing successful Palmaz-Schatz stent implantation alone during the same period served as controls.
Results. Atherectomy followed by stent implantation was performed in 94 patients with 98 lesions; periprocedural complications were observed in four cases. The stenosis diameter decreased from 76 +/- 9% at baseline to 30 +/- 13% after atherectomy (p < 0.0001), and 5 +/- 9% after stent implantation (p < 0.0001); it increased to 27 +/- 15% at 6 month angiography (p < 0.0001). During the 14 +/- 10 months of follow-up, none of the patients died or experienced myocardial infarction, but three patients under went target lesion revascularization. The patients undergoing stent implantation alone achieved smaller acute gains, tended to have a higher late lumen loss, had a higher restenosis rate (30.5% vs. 6.8%, p < 0.0001) and showed a greater incidence of clinical events during follow up (p < 0.0001).
Conclusions. Debulking atherosclerotic lesions by means of directional coronary atherectomy before stent implantation is a safe procedure with a high success rate and a low incidence of restenosis at follow-up. (J Am Coll Cardiol 1998;32:1855-60) (C) 1998 by the American College of Cardiology
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
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
Adjusted indirect comparison of new oral anticoagulants for stroke prevention in atrial fibrillation.
No full textRight subclavian approach as a feasible alternative for transcatheter aortic valve implantation with the CoreValve ReValving System.
No full textAims: Arterial access selection is crucial during transcatheter aortic valve implantation. When traditional femoral access has been deemed unfeasible the left subclavian artery has been used successfully. In cases where even the latter was ineligible, we opted, despite the lack of any data, for the right subclavian approach. We hereby present the results of the first series available. Our aim was to evaluate the feasibility and performance of the CoreValve ReValving System (CRS) implantation via the right subclavian artery in patients with contraindication to femoral and left subclavian accesses. Methods and results: Among 300 patients who have undergone CRS implantation, 70 (23%) have been treated via the subclavian approach, 10 via the right subclavian artery and 60 via the left. Demographic features were quite similar except for the presence of significant left subclavian disease in all patients treated via the right subclavian artery. The success rate was 100% for both groups. At 30-day follow-up, there was no significant difference in terms of all-cause mortality and cardiac mortality between right vs. left subclavian approach (0% vs. 6.6% and 0% vs. 6.6%, respectively). Consistent results were observed at a mean follow-up of 12±7.9 months (all-cause mortality: 10% vs. 15%). Incidences of new AV block requiring PM implantation were also statistically equivalent. Conclusions: CRS implantation via the right subclavian artery was as feasible and safe as the left subclavian approach. It poses very particular technical issues but should be considered when more conventional approaches are inadequate in order to provide patients with a further chance to be treated effectivel
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
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