1,721,002 research outputs found
Practicing appropriateness: the case of troponin.
No full textLaboratory testing significantly contributes to the clinical decision making, and the number of tests that a modern clinical laboratory can now perform is considerable. The impact of Laboratory Medicine in Cardiology has substantially evolved and increased over the past years. The cardiac troponin I and T (cTnI and cTnT) are universally regarded as the reference biomarkers for detection of myocardial injury and, understandably, for the diagnosis of myocardial infarction. Novel immunoassays for measurement of cTns have been recently introduced, which are characterized by a considerable improvement of analytical sensitivity and lower imprecision at low concentrations of the proteins. This assays, defined as last generation or high-sensitivity, allow to detect cTn concentrations that were virtually undetectable with the previous methods. On the one hand this has remarkably improved the diagnostic sensitivity for diagnosing myocardial infarction but, on the other, this has reduced the diagnostic specificity. A potential solution of this problem entails diagnostic algorithm based on the serial evaluation of these biomarkers, although the crucial issue still remains the appropriateness of the request. In conclusion, as often occurred in Laboratory Medicine, the leading problem with the use of highly-sensitivity cTn assays is the inappropriateness of ordering and interpretation of test results, and not the biomarker in itself
Blood cells characteristics as determinants of acute myocardial infarction.
No full textBackground: The aim of this study is to analyse the relation between red blood cells, platelets morphology and acute myocardial infarction (AMI), and to assess whether they could supplement the role of traditional cardiac biomarkers in the early identification of patients with AMI. Methods: All consecutive patients admitted to our emergency department between the 1st January and the 31st August 2009 due to chest pain of suspected cardiac origin were included in the study. All the patients underwent physical examination, a 12-lead ECG, blood sampling for determination of cardiac troponin I and a complete blood count. Results: A percentage of 6.7% of the 1971 patients had a confirmed diagnosis of AMI. Mean corpuscular volume (MCV), red blood cells distribution width (RDW) and platelets count (Plt) did not differ between patients with and without AMI. However, the mean platelet volume (MPV) was significantly higher in AMI patients (7.9 vs. 7.7 fL; p=0.0457). After stratification for gender, men with AMI displayed a lower RDW (p=0.0464) and a higher MPV (p=0.0062) as compared with those without AMI. The MCV and Plt were not significantly different. Women with AMI had a higher RDW (p=0.0079) as compared with those without AMI, while the MCV, Plt and MPV were not significantly different. Conclusions: Our study partially confirms previous data on the association between MPV or RDW and AMI. The inclusion of these parameters along with other conventional cardiac biomarkers might be a valuable perspective when evaluating patients with suspected AMI, although gender differences should be taken in account. © 2011 by Walter de Gruyter Berlin Boston
Copeptin for risk stratification in acute illness: beyond cardiological problems.
No full textCopeptin for risk stratification in acute illness: beyond cardiological problems
Reduced coronary flow reserve and parasympathetic dysfunction in patients with cardiovascular syndrome X
No full textOBJECTIVE:
Although cardiovascular syndrome X was described many years ago, its causes are still unclear. Many studies have addressed the autonomic function, whereas others have investigated the coronary reserve. The purpose of this study was to investigate the correlations between parasympathetic dysfunction and coronary flow reserve deficiency.
BASIC METHODS:
Eleven consecutive women suffering from cardiovascular syndrome X were enrolled in the study. All the patients underwent the analysis of heart rate and blood pressure variability, the cold face test and noninvasive evaluation of the coronary flow reserve by transthoracic echocardiography. Comparison was made with healthy volunteers.
RESULTS:
Seven patients (64%) showed vagal impairment in the analysis of heart rate and blood pressure variability and a pathological response to the cold face test, whereas four patients (36%) did not show significant differences from the control group. In these three groups, patients with and without vagal impairment and controls, there was a difference in the mean diastolic coronary velocity reserve (1.94+/-0.48; 3.73+/-0.95, 2.88+/-0.55, P=0.0005) and in maximal diastolic velocity reserve (2.00+/-0.48, 3.26+/-0.64, 2.65+/-0.57, P=0.0047). Post-hoc analysis demonstrated that the mean and maximal diastolic velocity reserves of the patients with vagal impairment seemed to be reduced compared with those of the other groups (P<0.05), which were similar.
CONCLUSIONS:
This study confirmed that syndrome X patients represent a heterogeneous group. More than half of the patients exhibited vagal dysfunction. In these patients, coronary flow reserve was abnormal compared with controls and other syndrome X patients without vagal impairment
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
Should We Continue Assessing Glomerular Filtration Rate with the Cockroft-Gault Formula in NOAC-Treated Patients? The Magnitude of the Problem
Full text linkDespite the proven superiority of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) over the Cockcroft-Gault (CG) formula, current guidelines recommend the latter to assess renal function in patients treated with non-vitamin K antagonist oral anticoagulants (NOACs). To assess the relationship between the CG and the recommended CKD-EPI formulas, in a cohort of atrial fibrillation (AF) patients treated with NOACs, and the misclassifications introduced by the CG formula for renal function levels, we estimated renal function with three equations: CG, CKD-EPI with body surface adjustment (1.73 mL/m(2), CKD-EPI) and without such adjustment (CKD-EPI_noBSA), in all consecutive AF patients discharged from NOACs from the Cardiology Division of a main city hospital between February 1st and May 31st 2018. We compared the different estimates of glomerular filtration rate and potential renal function class misclassifications. We reclassified 37/115 patients (32.1%) when switching from the CG to the CKD-EPI; and 24/115 (20.8%) switching from the CG to the CKD-EPI_noBSA formulas. Class reallocation was distributed across all levels of renal function, but mostly affected the "hyper-normal" function. In estimating consequences of such reallocation, a change in NOAC dosages would have occurred in 10/115 patients (8.7%) when switching from the CG to the CKD-EPI formula and in 10/115 patients when switching from the CG to the CKD-EPI_noBSA formula. Although the CG method has been traditionally used to calculate renal function in all NOAC studies, a renal dysfunction class reallocation occurs in a substantial fraction of hospital-admitted AF patients with the use of better estimates of renal function
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