1,720,956 research outputs found
Subadventitial techniques for chronic total occlusion percutaneous coronary intervention: The concept of “vessel architecture”
No full textDespite improvements in guidewire technologies, the traditional antegrade wire escalation approach to chronic total occlusion (CTO) recanalization is successful in only 60-80% of selected cases. In particular, long, calcified, and tortuous occlusions are less successfully approached with a true-to-true lumen approach. Frequently, the guidewire tracks into the subadventitial space, with no guarantee of distal re-entry into the true lumen. The ability to manage the subadventitial space has been a key step in the tremendous improvement in success rates of contemporary CTO percutaneous coronary intervention (PCI), whether operating antegradely or retrogradely. A modern approach to CTO PCI involves understanding the concept of "vessel architecture," which is based on the distinction between coronary structures (occlusive plaque, comprising the disrupted intima and media, and the outer adventitia) and extravascular space. The vessel architecture represents a safe work environment for guidewire and device manipulation. This review provides an anatomy-based description of the concept of vessel architecture, along with a historical perspective of subadventitial techniques for CTO PCI, and outcome data of CTO PCI utilizing the subadventitial space
Procedural and Long-Term Outcomes of Percutaneous Coronary Intervention for In-Stent Chronic Total Occlusion
No full textThe study sought to investigate the long-term outcomes and predictors of adverse events of percutaneous coronary intervention (PCI) for in-stent chronic total occlusion (IS-CTO). IS-CTO PCI has traditionally been associated with suboptimal success rates. We performed a multicenter registry of consecutive patients undergoing CTO PCI at 3 specialized centers. Patients were divided in IS-CTO and de novo CTO. The primary endpoint (major adverse cardiac events [MACE]) was a composite of cardiac death, target-vessel myocardial infarction, and ischemia-driven target-vessel revascularization (TVR) on follow-up. Independent predictors of MACE were sought with Cox regression. We included 899 patients (n = 111 IS-CTO, n = 788 de novo CTO). Baseline clinical and angiographic characteristics were balanced between the 2 groups. Overall mean J-CTO (Japanese-Chronic Total Occlusion) score was 1.88 ± 1.24 and mean PROGRESS-CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention-CTO) score was 1.04 ± 0.88. Antegrade wire escalation was used in 59.0% of IS-CTO and 48.1% of de novo CTO patients (p = 0.08). Procedural success was achieved in 86.5% in both groups (p = 0.99). After a median follow-up of 471 (interquartile range: 354 to 872) days, MACE were observed in 20.8% versus 13.9% in IS-CTO versus de novo CTO (p = 0.07), driven by TVR (16.7% vs. 9.4%; p = 0.03). IS-CTO was an independent predictor of MACE (hazard ratio: 2.16; 95% confidence interval: 1.18 to 3.95; p = 0.01), together with prior surgical revascularization and renal function, CTO PCI indicated for acute coronary syndrome, number of diseased vessels, and PROGRESS-CTO score. Procedural success was high and similar in patients with IS-CTO, as compared with de novo CTO. However, IS-CTO was independently associated with MACE (driven by TVR) on follow-up.S
Procedural and longer-term outcomes of wire- versus device-based antegrade dissection and re-entry techniques for the percutaneous revascularization of coronary chronic total occlusions
No full textBackground There are few data regarding the procedural and follow-up outcomes of different antegrade dissection/re-entry (ADR) techniques for chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Methods We compiled a multicenter registry of consecutive patients undergoing ADR-based CTO PCI at four high-volume specialized institutions. Patients were divided according to the specific ADR technique used: subintimal tracking and re-entry (STAR), limited antegrade subintimal tracking (LAST), or device-based with the CrossBoss/Stingray system (Boston Scientific, Marlborough, MA). Major adverse cardiac events (MACE: cardiac death, target-vessel myocardial infarction and target-vessel revascularization) on follow-up were the main outcome of this study. Independent predictors of MACE were sought with Cox regression analysis. Results A total of 223 patients were included (STAR n = 39, LAST n = 68, CrossBoss/Stingray n = 116). Baseline characteristics were similar across groups. Technical and procedural success was lower with STAR (59% and 59%), as compared with LAST (96% and 96%) and CrossBoss/Stingray (89% and 87%; p < 0.001 for both). At 24-month follow-up, MACE rates were higher in STAR (15.4%) and LAST (17.5%), as compared with device-based ADR with CrossBoss/Stingray (4.3%, p = 0.02), driven by TVR (7.7% vs. 15.5% vs. 3.1%, respectively; p = 0.02). Multivariable Cox regression analysis identified wire-based ADR (STAR and LAST) and total stent length as independent predictors of MACE. Conclusions In this multicenter cohort of patients undergoing CTO PCI with ADR techniques, STAR had lower success rates, as compared with the CrossBoss/Stingray system and LAST. The CrossBoss/Stingray system was independently associated with lower risk of MACE on follow-up, as compared with wire-based ADR techniques
Long‐term outcomes of rotational atherectomy for the percutaneous treatment of chronic total occlusions
No full textObjectives. To study the long-term outcomes of rotational atherectomy (RA) for chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Background. There is little evidence on the incidence, procedural results and long-term outcomes of RA for CTO PCI. Methods. This registry included data from consecutive patients undergoing CTO PCI at four specialized centers. Major adverse cardiac events (MACE: cardiac death, target-vessel myocardial infarction and ischemia-driven target-vessel revascularization) on follow-up were the primary endpoint. Results. A total of 1003 patients were included. Of these, 35 (3.5%) required RA. As compared with Conventional PCI, RA patients were older (68.9 ± 9.5 vs. 64.6 ± 10.7 years, P = 0.02), had higher prevalence of diabetes (58% vs. 37%, P = 0.01) and of a J-CTO score â¥2 (80% vs. 58%, P = 0.009), driven by severe calcification. Antegrade wire escalation was used more frequently in RA (74% vs. 53%, P = 0.08). RA was performed for balloon failure-to-cross in 51% and failure-to-expand in 49%. One burr was utilized in 86%. The 1.25-mm burr was the largest burr used in 43%. Slow flow/no-reflow was observed in 17%. No other serious RA-related complications were observed. Procedural success was 77% vs. 89% (P = 0.04) in RA vs. Conventional PCI. After a mean follow-up of 658 ± 412 days, MACE rates were similar between groups (15% vs. 13%, P = 0.70). Conclusions. The use of RA in CTO PCI was safe, despite a worse patient risk profile and higher procedural complexity, as compared with conventional techniques. Although procedural success was lower in the RA group, there were no differences in long-term clinical outcomes between groups. © 2016 Wiley Periodicals, Inc
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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