bluuebunny/crossref_metadata_2025_split huggingface dataset:
Significance of echocardiographic left atrial enlargement in aortic stenosis
Authors: Chandraratna P. A. N. , Aronow M. S. , Aronow W. S. 
Published: October 2013

AbstractThis study investigated the significance of echocardiographic left atrial enlargement as measured by the left atrial dimension corrected for body surface area in 24 patients with pure aortic stenosis established by cardiac catheterization. Echocardiographic evidence of left atrial enlargement occurred in 11 of 15 patients (73%) with an aortic valve area below 0.8 cm2 and in none of nine patients (0%) with an aortic valve area above 0.8 cm2, p < 0.0025. All 11 patients (100%) with an enlarged left atrial dimension had an increased diastolic left ventricular dimension, whereas 1 of 13 patients (8%) with a normal left atrial dimension had an increased diastolic left ventricular dimension, p < 0.00001. The 11 patients (100%) with an enlarged left atrial dimension had increased posterior left ventricular wall thickness, whereas 2 of 13 patients (13%) with a normal left atrial dimension had increased posterior left ventricular wall thickness (p < 0.0005). These data lead one to conclude that in patients with pure aortic stenosis, echocardiographic evidence of left atrial enlargement as measured by an increased left atrial dimension corrected for body surface area should lead one to suspect severe aortic stenosis.
Left ventricular function in asymptomatic patients with severe aortic regurgitation: Relation to clinical parameters and exercise performance
Authors: Thompson R. , Ross I. , McHaffie D. , Leslie P. , Easthope R. , Elmes R. 
Published: October 2013

AbstractThe optimal time for valve replacement in asymptomatic patients with severe aortic regurgitation is uncertain and is usually based on changing patterns in the ECG, radiographic heart size, or decreasing effort tolerance. The relationship between these parameters and changes in left ventricular function however has not been defined. In this study 28 patients, ages 20 to 66 years (mean 35 years) underwent gated pool radionuclide imaging at rest and at submaximal exercise (to greater than 85% maximum heart rate predicted for age) to quantitate ejection fraction (EF) and severity of aortic regurgitation. All patients had a 12‐lead ECG and chest x‐ray and 18 patients underwent echocardiography and maximal treadmill exercise testing. Severity of left ventricular hypertrophy on ECG was assessed by the Estes scoring system, heart size was expressed as cardiothoracic ratio (CTR). Echocardiograms were analyzed with respect to left ventricular end‐systolic diameter (LVESD) and fractional shortening. EF was below the normal range at rest (<0.45%) in only 6 patients (21%), but was abnormal during exercise in 18 patients (64%). Reduction in EF on exercise by 20% was judged to represent significant deterioration and occurred in 12 patients (43%), all of whom had an EF of less than 0.45% on exercise. Comparison of ECG, heart size, echocardiogram, exercise performance, and resting EF in this group of 12 patients with the remaining 16 patients showed no significant differences. In the group as a whole, stress EF was abnormal in 14 of 19 patients (73%) with an Estes score of 5 or greater, and was significantly lower (p < 0.05, mean 0.42) than in patients with an Estes score less than 5 (mean 0.52). There was no significant correlation between EF at rest or during exercise and any of the other parameters. Severity of aortic regurgitation (regurgitant fraction) showed poor correlation with heart size and LVESD (r = 0.24 and 0.32, respectively). It is concluded that abnormalities of left ventricular function can be demonstrated on exercise in a significant proportion of patients with aortic regurgitation despite the absence of symptoms, and that these changes cannot be predicted by readily available clinical parameters or by assessment of resting left ventricular function. Gated pool imaging may be a sensitive method for detection of early changes in LV function in these patients, but its value in assessing the timing of valve replacement requires serial investigation.
Risk factors and late recurrence of angina following myocardial revascularization
Authors: Schackman P. E. , Bamrah V. S. , Tristani F. E. , Barboriak J. J. , Hughes C. V. , Pedersen D. H. , Anderson A. J. 
Published: October 2013

AbstractTo assess the influence of risk factors on the recurrence of angina several years after myocardial revascularization, 316 patients were studied. We report that 249 patients obtained relief of angina from coronary bypass surgery and remained free of angina up to 4 years later. The remaining 67 patients experienced initial relief of angina 1 year following bypass surgery and then, subsequently, redeveloped angina 4 years postsurgery. There was no statistical difference in any risk factor between patients who remained free of angina after myocardial revascularization and those who developed angina. Of the total 316 patients, 79% were free of angina 4 years after coronary bypass surgery.
Combined supravalvular aortic stenosis and hypertrophic subaortic stenosis: Coexistence or association?
Authors: Bashour T. , Kabbani S. , Saalouke M. , Sandouk A. , Cheng T. O. 
Published: October 2013

AbstractA 19‐year‐old male was found to have combined supravalvular aortic stenosis and hypertrophic subaortic stenosis. Two possible hypotheses with supportive evidence in the literature may explain this association: (1) long‐standing fixed supravalvular aortic stenosis may result in secondary hypertrophic subaortic stenosis, and (2) infantile hypercalcemia, a condition closely related to supravalvular aortic stenosis, may also be involved by continuous inotropic stimulation in the pathogenesis of muscular hypertrophy and subaortic stenosis of the left ventricle. We tend to favor the second theory in light of recent evidence in the literature.
Echocardiographic appearances of right atrial thrombus
Authors: Oldershaw P. J. , Coll L. 
Published: October 2013

AbstractA 17‐year‐old male presented with a four‐day history of increasing shortness of breath and right basal pleuritic chest pain. Physical examination revealed central and peripheral cyanosis, sinus tachycardia, elevation of central venous pressure, hypotension, and added third heart sound. Echocardiography (M‐mode and two‐dimensional) showed a highly mobile mass in the right atrium apparently attached to the interatrial septum. A diagnosis of right atrial myxoma with pulmonary embolization was made and urgent surgery advised. At operation a string of thrombus in the right atrium (presumed from peripheral venous site) occluding a patent foramen ovale was found. The usefulness of echocardiography in diagnosing atrial thrombus and in differentiating clot from tumor is discussed.
Acute febrile mucocutaneous lymph node syndrome (Kawasaki disease) in an adult
Authors: Takamoto T. , Niwa A. , Taniguchi K. , Takeuchi J. 
Published: October 2013

AbstractThe patient is a 31 ‐year‐old man with a febrile condition accompanied by mucocutaneous changes and swelling of cervical lymph nodes. Clinical features and laboratory data meet the criteria for acute febrile mucocutaneous lymph node syndrome (MCLS). In addition, coronary artery aneurysms and stenotic lesions were observed in the coronary arteriograms. Previously reported cases of MCLS in adults have been extraordinarily rare.
Simplified application of bayesian analysis to multiple cardiologic tests
Authors: Staniloff H. M. , Diamond G. A. , Freeman M. R. , Berman D. S. , Forrester J. S. 
Published: October 2013

AbstractBayes' theorem is an accepted method to integrate the results of multiple tests for coronary artery disease, but complicated calculations make its application awkward for the clinician. This report presents tables which allow the reader to serially apply Bayes' theorem to the results of stress electrocardiography, thallium scintigraphy, technetium blood‐pool scintigraphy, and cardiac fluoroscopy.
Reassessment of electrovectorcardiographic signs of left atrial enlargement
Authors: Perosio A. M. , Suarez L. D. , Torino A. , Llera J. J. , Ballester A. , Roisinblit J. M. 
Published: October 2013

AbstractEchocardiographic left atrial size was correlated with 27 electrovectorcardiographic parameters in 93 subjects. In 20 of them hemodynamic studies, including calculation of the left atrial volume, were performed. Subjects were divided into four groups as follows: Group I, 21 healthy subjects; group II, 45 patients with heart disease but no left atrial enlargement; group III, 15 patients with heart disease and left atrial size from 4.1 to 5 cm; and group IV, 12 patients with heart disease and a left atrial size exceeding 5 cm. A good correlation was found between left atrial size and the following parameters: Duration of P wave in standard lead II, voltage of both terminal forces of P wave in lead V1 and its maximal vector in the frontal and sagittal planes. A new index (duration/voltage of P wave in lead II) was postulated, which showed an excellent correlation with left atrial size (p < 0.001). In all cases the superposition between groups was excessive. These findings indicate the limitations of the classical patterns and raise interest in new parameters concerning the electrocardiographic diagnosis of left atrial enlargement.
Clinical characteristics and prognosis of patients with postinfarction angina caused by coronary artery spasm
Authors: Koiwaya Y. , Nakagaki O. , Takeshita A. , Nakamura M. 
Published: October 2013

AbstractClinical features and the course of 15 patients with postinfarction angina caused by coronary artery spasm are described. Episodes of postinfarction angina in the patients recurred at rest in the early recovery phase and were accompanied by transient ST‐segment elevation. The area where ST‐segment elevations were demonstrated on a 12‐lead ECG always included the leads with newly developed abnormal Q waves. Pain resolved spontaneously or after sublingual nitroglycerin in several minutes. Holter ECGs during a 24‐h period demonstrated frequent episodes of ST‐segment elevation that were not always associated with chest pain. Treatment with calcium antagonist and/or nitrates effectively suppressed angina, and only one patient developed reinfarction. The patient's subjective symptoms were abolished by diltiazem and isosorbide dinitrate. A Holter ECG of the patient revealed silent ST‐segment elevations before and after the reinfarction and an increase of the drugs completely suppressed the recurrence of silent ischemic ECG changes. Coronary arteriograms were obtained from 8 patients, which demonstrated more than 75% segmental stenosis on one coronary artery in 5 patients and no significant obstruction in the remaining 3. All patients performed a treadmill exercise stress test before discharge and most demonstrated excellent tolerance. All patients experienced no form of chest pain for an average of 25 months follow‐up under medication. We conclude that among patients with postinfarction angina, those cases caused by coronary artery spasm have a relatively good prognosis.
Current problems in hypertension
Authors: Franciosa J. A. 
Published: October 2013

AbstractAlthough the beneficial effects of treating hypertension remain firmly established, concern has recently arisen that certain antihypertensive drugs may adversely modify cardiovascular risk factors. Equipotent blood pressure‐lowering agents may also have differing effects on cardiac structure and function. Thus, established approaches to antihypertensive therapy are being questioned and revised or new approaches are being suggested.
Fluorophore‐Labeled Cyclooxygenase‐2 Inhibitors for the Imaging of Cyclooxygenase‐2 Overexpression in Cancer: Synthesis and Biological Studies
Authors: Bhardwaj Atul , Kaur Jatinder , Wuest Frank , Knaus Edward E. 
Published: October 2013

AbstractA group of cyclooxygenase‐2 (COX‐2)‐specific fluorescent cancer biomarkers were synthesized by linking the anti‐inflammatory drugs ibuprofen, (S)‐naproxen, and celecoxib to the 7‐nitrobenzofurazan (NBD) fluorophore. In vitro COX‐1/COX‐2 inhibition studies indicated that all of these fluorescent conjugates are COX‐2 inhibitors (IC50 range: 0.19–23.0 μM) with an appreciable COX‐2 selectivity index (SI≥4.3–444). In this study the celecoxib–NBD conjugate N‐(2‐((7‐nitrobenzo[c][1,2,5]oxadiazol‐4‐yl)amino)ethyl)‐4‐(5‐(p‐tolyl)‐3‐(trifluoromethyl)‐1H‐pyrazol‐1‐yl)benzenesulfonamide (14), which displayed the highest COX‐2 inhibitory potency and selectivity (COX‐2 IC50=0.19 μM; SI=443.6), was identified as an impending COX‐2‐specific biomarker for the fluorescence imaging of cancer using a COX‐2‐expressing human colon cancer cell line (HCA‐7).
Kinetic Modeling of Hydrogen Abstractions Involving Sulfur Radicals
Authors: Vandeputte Aäron G. , Reyniers Marie‐Françoise , Marin Guy B. 
Published: October 2013

AbstractOne of the requisites for the development of detailed reaction networks is the availability of accurate kinetic data. Group additivity based models linking the Arrhenius parameters to structural characteristics of the transition state have proven to be a valuable tool to obtain those data. In this work, group additivity values are presented to allow a broad range of CH and SH hydrogen abstraction reactions by S radicals to be modeled. Rate coefficients in the temperature range from 300 to 1500 K are obtained by using the CBS‐QB3 method in the high‐pressure limit and are corrected for tunneling and anharmonicity of rotation about the transitional bond. A total of 149 reactions are studied. From these reactions, a total of 52 group additivity values and 35 resonance corrections are derived. The general applicability of the group additivity method is demonstrated for a test set containing 25 reactions. At 300 K, rate coefficients are on average reproduced within a factor of 2.8. The mean absolute deviations on the Arrhenius parameters are 2 kJ mol−1 for the activation energy and 0.38 for log A in which A is the pre‐exponential factor.
Using Platelet Function Testing to Guide Antiplatelet Therapy
Authors: Linden Matthew D. 
Published: October 2013

ABSTRACT

Clinical Development Phases I‐III Regulatory, Quality, Manufacturing

Platelets are subcellular fragments in blood whose activation is central to atherothrombosis and cardiovascular events. Platelet activation is complex, with multiple pathways of initiation and amplification involved. Antiplatelet drugs may target any of these pathways to diminish the propensity of platelets to become activated. The most well‐established antiplatelet drugs, aspirin and thienopyridines, target the thromboxane and adenosine diphosphate auto‐amplification pathways of platelet activation, respectively. These are very effective medicines, but response varies and residual on‐treatment platelet function is associated with poorer clinical outcomes. Alternative antiplatelet therapies are available and more are in development. Therefore, tailoring antiplatelet therapy to on‐treatment platelet activation is an appealing strategy and the subject of investigation. There are many different approaches to measuring platelet activation and response to stimulation with antiplatelet therapy, but there is very little agreement between them regardless of the cutoffs used. Therefore, selection of the appropriate platelet function test is important in assessing on‐treatment platelet activation for guided therapy. Recent research has shown that tailoring antiplatelet therapy can improve these laboratory measures of platelet activation, but clinical studies that assess cardiovascular benefit against potential for increased bleeding are required.
The Fall and Rise of Cangrelor
Authors: Leonardi Sergio , Ferlini Marco , Marino Marcello , Visconti Luigi Oltrona 
Published: October 2013

Abstract

Clinical Development Phases I‐III Regulatory, Quality, Manufacturing

The antagonism of the platelet P2Y12 receptor is essential for the treatment of patients undergoing percutaneous coronary intervention (PCI). Cangrelor is an intravenous P2Y12 receptor antagonist that being both reversible and very short acting has the potential to overcome some of the limitations of currently available oral agents like clopidogrel, prasugrel, and ticagrelor. Cangrelor has been studied in a large phase III program called Cangrelor versus standard therapy to acHieve optimal Management of Platelet InhibitiON (CHAMPION) that included three randomized controlled trials (RCTs): PCI, PLATFORM, and PHOENIX. The first two RCTs, conducted concurrently, were prematurely interrupted for futility. However, it was soon evident that unanticipated challenges in the ascertainment of PCI‐related myocardial infarction (MI) due to shorter‐than‐expected times to cardiac catheterization may have reduced the ability to detect cangrelor efficacy. While CHAMPION PCI and PLATFORM were ongoing, the universal definition of MI provided recommendations to address these challenges. Specifically, this consensus document recommended the presence of a rise and/or a fall of cardiac biomarkers to define MI. The universal MI definition enhanced by novel approaches to efficiently and accurately implement this definition was used to adjudicate MI in PHOENIX, which showed superiority of cangrelor over clopidogrel, with an effect that was mostly evident in MI. The development of cangrelor illustrates the critical importance of PCI‐related MI as end point, the challenges in its definition in patients undergoing a very early invasive management, and the role of the universal MI definition in overcoming these challenges.
Heparin‐Induced Thrombocytopenia: Pathophysiology, Diagnosis, and Treatment Monitoring
Authors: Kyriakou Elias S. , Kokori Styliani I. , Stylos Dimitrios A. , Kardoulaki Aikaterini P. , Tsantes Argyrios E. 
Published: October 2013

ABSTRACT

Clinical Development Phases I‐III Regulatory, Quality, Manufacturing

Heparin‐induced thrombocytopenia (HIT) without or with thrombosis (HIT‐T) constitutes an acquired immune prothrombotic state, occurring in patients under unfractionated heparin or rarely low molecular weight heparin treatment. Heparin binding to secreted platelet factor‐4 (PF4) generates PF4 neo‐epitopes, against which polyclonal IgG‐antibodies are produced. IgG‐Hep/PF4 complexes bind on specific platelet, monocyte and endothelial cell Fcγ surface receptors, causing platelet consumption (thrombocytopenia), cell activation, release of prothrombotic tissue factor‐bearing microparticles and thrombin generation. Mild to moderate thrombocytopenia and venous or arterial thrombosis are the two hallmarks of HIT. “4T” scoring‐system predicts HIT‐probability, while diagnosis is further confirmed via specific laboratory assays, which reveal either the presence of IgG antibodies against Hep/PF4 complex (immunological assays), or whether patient's serum can activate donor platelets in the presence of heparin (functional assays). HIT‐treatment imposes immediate heparin cessation and initial parenteral anticoagulation with alternative anticoagulants, such as direct thrombin inhibitors (DTIs: lepirudin, argatroban, bivalirudin, desirudin) or indirect FXa inhibitors (IXaIs: danaparoid, fondaparinux). Monitoring of DTIs and IXaIs (via activated partial thromboplastin time or modern assays such as hemoclot thrombin inhibitor and anti‐Xa activity, respectively) is essential especially in patients with renal or hepatic failure or in patients with HIT‐related consumptive coagulopathy, in order to avoid serious bleeding events or anticoagulant underdosing. Vitamin K antagonists, which are contraindicated during acute phase, are permitted only after platelet count has substantially recovered and must be continued for at least 30 days and 3 months in isolated HIT and HIT‐T, respectively, with target international normalized ratio (INR) between 2.0 and 3.0.
Coagulation Assays in Patients with New Oral Anticoagulants (NOACs): Why? When?
Authors: Samama Meyer Michel 
Published: October 2013

ABSTRACT

Clinical Development Phases I‐III Regulatory, Quality, Manufacturing

Treatment with new oral anticoagulant drugs does not require laboratory monitoring. However, there are some clinical settings where the measurement of the anticoagulant activity can be useful, especially in urgent surgery or invasive procedure. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are prolonged with good correlation with plasma drug concentration. The influence of rivaroxaban on PT is greater than that on aPTT, in contrast to dabigatran. Apixaban responses to PT and aPTT are weak. These tests are not specific and cannot detect low plasma concentrations. For direct Factor‐Xa inhibitors, the most appropriate test is a modified anti‐Xa chromogenic assay. A specific test unresponsive to heparins and fondaparinux has been developed. For dabigatran measurement, a modified thrombin clotting time, “Hemoclot,” has been well documented. The use of plasma calibrators allows an expression of the results in ng/ml of plasma. Expected peak concentration (2 to 4 h after drug intake) and trough concentration or Cmin—before a repeated administration—have been determined. More clinical work is warranted to determine possible adjustments of the drug according to its plasma concentration. Finally, the potential advantage of a punctual screening during long‐term treatment has not been investigated.
A Robust and General Protocol for the Lewis‐Base‐Catalysed Reaction of Alcohols and Alkyl Propiolates
Authors: Tejedor David , Álvarez‐Méndez Sergio J. , López‐Soria Juan M. , Martín Víctor S. , García‐Tellado Fernando 
Published: October 2013

AbstractA general and practical protocol for the tertiary‐amine‐catalysed synthesis of β‐alkoxyacrylates from primary, secondary, and tertiary alcohols is described. Of the currently used catalysts, DABCO proved to be the best one for this process. Three factors seem to influence the outcome of the reaction: (1) the nucleophilic strength of the catalyst, (2) the electrophilicity of the intermediate ammonium acrylate, and (3) the pKa/nucleophilicity of the alcohol/alkoxide nucleophile. Reactivity tuning enables the transformation of a range of tertiary alcohols into the corresponding β‐alkoxyacrylate derivatives. Differences in the reactivity of different types of alcohol allow the selective transformation of diols containing two different hydroxy groups into the corresponding monoprotected derivatives. This protocol will aid other synthetic organic chemists to easily prepare such vinyl ethers under atom‐economic, efficient, and bench‐friendly reaction conditions.