1,720,994 research outputs found
Long-term clinical outcomes following sirolimus-eluting stent implantation in patients with acute myocardial infarction. A meta-analysis of randomized trials
No full textObjectives The aim of this study was to perform a metaanalysis of randomized trials, evaluating the long-term outcomes of sirolimus-eluting stents (SES) versus baremetal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI). Background Despite short-term outcomes of patients with STEMI undergoing primary percutaneous coronary intervention indicate a benefit of SES in terms of reintervention, several concerns remain on the long-term safety and efficacy of SES. Methods A systematic literature search of electronic resources, through October 2011, was performed using specific search terms. Included trials were randomized studies comparing SES to BMS in STEMI patients, with a follow-up C3 years. Results Seven trials were included, with a total of 2,364 patients. At a median follow-up of 3 years, SES significantly reduced the risk of target-vessel revascularization when compared with BMS [odds ratio (OR), 0.44; 95 % confidence interval (CI), 0.34-0.57; p<0.0001], without increasing the risk of mortality (OR 0.78; 95 % CI, 0.57-1.08; p = 0.14), reinfarction (OR 0.91; 95 % CI, 0.61-1.35, p = 0.64) and early to late stent thrombosis (OR 0.77; 95 % CI, 0.49-1.20; p = 0.25). However after the first year, SES did not further reduce target-vessel revascularization (OR 1.06; 95 % CI, 0.64-1.74; p = 0.83) and increased the risk of very late stent thrombosis (OR 2.81; 95 % CI, 1.33-5.92; p = 0.007). Conclusions At long-term follow-up, SES compared to BMS use in STEMI patients reduces the risk of targetvessel revascularization, without increasing the risk of death and reinfarction. However, the strong SES efficacy is counterbalanced by a significant risk of very late stent thrombosis. © Springer-Verlag 2012
Genetically Determined Platelet Reactivity and Related Clinical Implications
No full textMany drugs are nowadays available to inhibit platelet activation and aggregation, especially in patients with acute coronary syndromes and undergoing percutaneous coronary intervention with stent implantation. Primary targets are represented by enzymes or receptors involved in platelet activation. Genetic mutations in these targets contribute to the inter-individual variability in platelet responses therefore weakening the efficacy of antiplatelet agents. High on treatment platelet reactivity is a condition characterized by low levels of platelet inhibition despite the use of antiplatelet drugs. This could be responsible for re-infarction, stent-thrombosis and strokes, affecting short and long-term prognosis after coronary revascularization. So far, to test antiplatelet resistance either the assessment of platelet function or the identification of genetic carriers of poly morphisms have been pursued. Although several methods are now available to test platelet reactivity, it is still debated whether its routine assessment gives real benefits in clinical practice. The present review aims at examining current evidences on genetic polymorphisms affecting optimal platelet inhibition
Early stent thrombosis with bivalirudin in patients undergoing percutaneous coronary intervention. A meta-analysis of randomised clinical trials
No full textAlthough bivalirudin has been shown to reduce bleeding events in patients undergoing percutaneous coronary intervention, residual concerns remain about a possible higher risk of early (within 30 days) stent thrombosis (ST). Therefore, we performed a meta-analysis of randomised trials reporting ST events with bivalirudin compared to other antithrombotic therapies (heparins ± glycoprotein IIb/IIIa inhibitors). A systematic literature search of electronic resources was performed through May, 2014. The primary endpoint was definite early ST, according to Academic Research Consortium criteria. Secondary endpoints included: all-cause death, myocardial infarction and major bleeding. A total of 11 trials, including 16,415 patients, were accrued. Compared to other regimens, bivalirudin significantly increased the risk of early ST (odds ratio [OR]=1.80; 95 % confidence interval [CI], 1.28-2.52; p=0.0007) and reduced the risk of major bleeding (OR [95 %CI]=0.64 [0.51-0.82], p=0.0003), with a comparable risk of mortality or myocardial infarction. The higher risk of early ST was mainly attributable to acute (OR [95 % CI] =4.33 [2.33-8.05], p < 0.001) than subacute (OR [95 % CI] =0.89 [0.53-1.50], p =0.67) ST events (p for interaction < 0.001). Non-fatal myocardial infarction was the most common presentation (83 %) of early ST events, while death occurred infrequently (about 5 %). In conclusion, in patients undergoing PCI, bivalirudin compared to heparins is associated with a higher risk of early ST, which is mainly related to more frequent acute events. Further studies are required to evaluate alternative strategies to mitigate this risk, without hampering the benefits derived from the reduction in bleeding events with bivalirudin
Impact of genetic polymorphisms on platelet function and response to anti platelet drugs
No full textCardiovascular genomic consists in the identification of polymorphic genes responsible for the susceptibility to cardiovascular disease including coronary artery disease (CAD). Genes involved in platelet activation and aggregation play a key role in the predisposition to CAD. A considerable inter-variability of platelet response to agonists and to drugs exists and in particular the hyper-reactivity phenotype seems to be heritable. Besides glycoproteins and receptors expressed on platelets surface whose mutations significantly impact on platelet function, moreover researchers in the last decades have paid great attention to the genes involved in the response to anti-platelet drugs, considering their pivotal role in the treatment and outcomes of CAD patients especially those undergoing PCI. With the outbreak of advanced techniques developed to analyse human genetic footprints, researchers nowadays have shifted from genetic linkage analysis and a candidate gene approach toward genome-wide association (GWAS) studies and the analysis of miRNA-mRNA expression profiles
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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