1,721,034 research outputs found
Influence of concomitant mitral valve dysfunction on survival after aortic valve replacement
No full textAortic valve pathology is the most common acquired valvular heart disease in the adults of western countries, and mitral regurgitation (MR) is often clinically present in patients with degenerative aortic stenosis or insufficiency. Many studies report an incidence of MR between 65-75% in patients evaluated for aortic valve replacement Severe aortic valve disease may be associated with functional mitral regurgitation (FMR) defined as the failure of mitral valve to prevent systolic backward flow in the absence of any significant structural or intrinsic valvular disease. Increased afterload and left ventricular remodeling have been implicated to explain FMR in patients with aortic valve disease. Moreover, organic mitral valve disease can be associated with aortic stenosis and can be rheumatic or degenerative. We have examined the data of the literature to understand the evolution of MR, the impact of mitral regurgitation on the outcome of patients undergoing aortic valve replacement, and to determine clinical predictors of prognosis in patients with concomitant MR at the time of aortic valve replacement
The use of robotic technology in the LAST operation
No full textBACKGROUND:
The LAST operation represents a good option for single left anterior descending artery (LAD) revascularization. We report our preliminary experience with the LAST operation performed with the aid of the "da Vinci" Intuitive robotic system.
METHODS:
From January 2000 to May 2001, 12 patients (11 males and 1 female, mean age 62 +/- 8 years) underwent the LAST operation. All patients had a proximal LAD lesion either not suitable for coronary angioplasty or unsuccessfully treated at coronary angioplasty previously. The mean preoperative ejection fraction was 55 +/- 5%. In all patients, left internal mammary artery (LIMA) harvesting was carried out endoscopically using robotic technology. After heparin administration the LIMA was distally divided to check the adequacy of the blood flow. An incision of about 6 cm was then made in the appropriate intercostal space and the LAD was exposed using a special costal retractor. Following the insertion of a temporary intracoronary shunt, the LIMA was anastomosed to the LAD.
RESULTS:
No hospital or delayed death occurred. Uneventful conversion to midline sternotomy was necessary in one patient who developed ischemic changes and hemodynamic instability. One patient had a revision for postoperative bleeding. All patients were discharged within the first postoperative week and in 4 of them optimal patency of the LIMA graft was angiographically documented.
CONCLUSIONS:
The use of robotic technology seems to overcome all the drawbacks associated with the LAST operation and enhances the role of minimally invasive surgery in coronary artery revascularization
Totally endocsopic atrial septal defect closure with a robotic system: Experience with seven cases
No full textBackground: The development of minimally invasive cardiac surgery has shown good clinical results with shorter recovery time and better cosmetic results. The introduction of the robotic systems can further reduce the surgical trauma and improve the surgical dexterity. We report seven cases of complete closed chest atrial septal defect closure using the "da Vinci"TM Surgical System (Intuitive Surgical, Mountain View, CA). Methods: Following peripheral cannulation for cardiopulmonary bypass (CPB), aortic occlusion and cardioplegia delivery, five patients with atrial septal defect (ASD) and two patients with patent forame ovale (PFO) with atrial septal aneurysm (ASA) were successfully treated using the robotic system. Two robotic arms and an endoscopic camera were inserted through ports in the right hemithorax and an accessory port was placed for blood suction and ancillary instruments insertion. The defect closure was carried out with interrupted stitches in one patient and with a continuous suture in the others. Results: Mean cardiopulmonary bypass and cross clamp time were 101.8 ± 39.6 and 63.4 ± 21.9 minutes respectively. Extubation was carried out within the seventh postoperative hour. All patients returned to normal lifestyle in one week. Conclusion: Complete closed chest ASD closure can be carried out using robotic technique with rapid postoperative recovery and excellent cosmetic result
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
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