39 research outputs found

    Electrochemical studies of Mn(II) mediated by Li+ doped Indium Titanium Oxide (ITO) electrode.

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    An electrochemical investigation of Manganese species has been carried out by using cyclic voltammetry (CV) at Lithium doped Indium Tin Oxide (ITO) electrode. The doping of the Li+ ion onto the Indium Tin Oxide (ITO) electrode was carried out to 10 potential cycling in the presence of 0.1M LiOH. The modified Li+/ITO electrode used as working electrode and was applied for the detection of Mn(II) in 0.1M KCl aqueous solution using cyclic voltammetry (CV). Electrode responses were obtained for the reduction of 50μM of Mn(II) at lithium doped modified ITO electrode, and bare ITO electrode. A well defined peak appeared at -136mV vs Ag/AgCl with a current enhancement and peak potential shift toward higher potential due to the presence of Lithium doped. Besides that, the presence of Lithium doped caused an increase of the reduction peak of Mn (II) ion (current enhancement) by about 2.9 times compared to use of bare ITO electrode. The optimum physical and chemical conditions such as pH, concentration of Mn(II) ion solution, and scan rate for current enhancement would be obtained. A linear relationship (y= 1777.3x + 42.145, R2=0.995) was observed for the plot of current (μA) versus concentration range of 10μM to 1.0mM of Manganese in 0.1M KCl using Lithium doped modified ITO electrode. Based on the background noise of 50 data points, adjacent to the reduction peak of Mn (II), and 3σ/slope, a detection limit of 1.0nM was determined

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

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    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation.

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    OBJECTIVES: To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks. DESIGN: The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA2DS2-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). PARTICIPANTS: Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk. RESULTS: The discriminatory value of the GARFIELD-AF risk model was superior to CHA2DS2-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA2DS2-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA2DS2-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA2DS2-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74). CONCLUSIONS: Performance of the GARFIELD-AF risk tool was superior to CHA2DS2-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710)

    Two-year outcomes of patients with newly diagnosed atrial fibrillation: results from GARFIELD-AF.

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    AIMS: The relationship between outcomes and time after diagnosis for patients with non-valvular atrial fibrillation (NVAF) is poorly defined, especially beyond the first year. METHODS AND RESULTS: GARFIELD-AF is an ongoing, global observational study of adults with newly diagnosed NVAF. Two-year outcomes of 17 162 patients prospectively enrolled in GARFIELD-AF were analysed in light of baseline characteristics, risk profiles for stroke/systemic embolism (SE), and antithrombotic therapy. The mean (standard deviation) age was 69.8 (11.4) years, 43.8% were women, and the mean CHA2DS2-VASc score was 3.3 (1.6); 60.8% of patients were prescribed anticoagulant therapy with/without antiplatelet (AP) therapy, 27.4% AP monotherapy, and 11.8% no antithrombotic therapy. At 2-year follow-up, all-cause mortality, stroke/SE, and major bleeding had occurred at a rate (95% confidence interval) of 3.83 (3.62; 4.05), 1.25 (1.13; 1.38), and 0.70 (0.62; 0.81) per 100 person-years, respectively. Rates for all three major events were highest during the first 4 months. Congestive heart failure, acute coronary syndromes, sudden/unwitnessed death, malignancy, respiratory failure, and infection/sepsis accounted for 65% of all known causes of death and strokes for <10%. Anticoagulant treatment was associated with a 35% lower risk of death. CONCLUSION: The most frequent of the three major outcome measures was death, whose most common causes are not known to be significantly influenced by anticoagulation. This suggests that a more comprehensive approach to the management of NVAF may be needed to improve outcome. This could include, in addition to anticoagulation, interventions targeting modifiable, cause-specific risk factors for death. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Electrochemical oxidation/reduction of selected compounds mediated by indium tin oxide doped with lithium and glassy carbon electrode modified with tin dioxide

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    The new chemically modified electrodes based on indium tin oxide (ITO) doped with lithium (Li+/ITO) and tin oxide modified glassy carbon electrode (SnO2/GCE) were fabricated by potential cycling and mechanical attachment methods, respectively. The Li+/ITO electrode and SnO2/GCE has been characterized using voltammetric techniques of cyclic voltammetry, chronoamperometry and chronocoulometry in this work. The Li+/ITO electrode was applied in the electrochemical determination of 50 μM Mn(II) in 0.1 M KCl (pH 6.9) and 50 μM Hg(II) in 0.1 M KCl (pH 6.4). The current enhancements of 2.9 times for the reduction of Mn(II) and 2.7 times for the reduction of Hg(II) were obtained by using the Li+/ITO electrode compared to unmodified ITO electrode. Under the optimized parameters, the linear calibration graph showed correlation coefficient of 0.992 for the reduction of 10 μM to 1.0 mM Hg(II) and 0.995 for the concentration isotherm of Mn(II) in the range of 10 μM to 1.0 mM, with a linearity up to 0.2 mM. From this calibration plot, high sensitivity response of 2298.1 μA/mM with detection limit of 78.3 nM for the reduction of Hg(II) and 1777.3 μA/mM with detection limit of 100 nM for the reduction of Mn(II) at the Li+/ITO electrode were obtained Effect of scan rate of Hg(II) and Mn(II) was studied in the range of 5 mV/s to 200 mV/s, and linear relation was observed. Based on the plot of log reductive current vs. log scan rate, experimental slopes of 0.38 and 0.84 were obtained for Hg(II) and Mn(II) respectively, indicating that the reaction under diffusion controlled and surface complex reaction respectively. Diffusion coefficient was calculated as 5.75x10-6 cm2/s and 2.54x10-7 cm2/s from the chronocoulometry study, and the activation energy obtained was 20.79 kJ/mol and 12.42 kJ/mol for Mn(II) and Hg(II) respectively in aqueous media at the Li+/ITO electrode. Excellent analytical and recovery rates have been obtained using either lake or sea water samples spike with the analyte. Besides, the bulk SnO2/GCE was used for the electrochemical determination of 1.0 mM of ascorbic acid in 0.1 M KCl (pH 5), whereas spherical SnO2/GCE was applied in the electrochemical determination of 1.0 mM of Hg(II) in 0.1 M KCl (pH 7.4). The current enhancements of 1.4 times for the oxidation of ascorbic acid and 1.5 times for the reduction of Hg(II) were also obtained by using bulk SnO2/GCE and spherical SnO2/GCE respectively compared to bare GCE. Calibration plot reveals linearity from the range of 20 μM to 2.0 mM with a correlation coefficient of 0.993 for the detection of ascorbic acid and concentration isotherm of Hg(II) in the range 0.5 μM to 1.0 mM, with linearity of up to 10 μM with a correlation coefficient of 0.999. The sensitivity and detection limit was estimated to be 23.47 μA/mM and 2.5 μM respectively for ascorbic acid and 61.79 μA/mM and 75 nM respectively for Hg(II). Furthermore, the diffusion coefficient and activation energy of ascorbic acid using bulk SnO2/GCE were estimated to be 8.09 x 10-9 cm2/s and 14.26 kJ/mol respectively while the values of the diffusion coefficient and activation energy of Hg(II) using spherical SnO2/GCE were 2.84x10-6 cm2/s and 21.66 kJ/mol respectively. Practically, SnO2 modified GC electrode could be used for the determination of ascorbic acid in rose syrup sample and Hg(II) in sea water sample. Therefore, the use of Li+/ITO electrode and SnO2/GCE are highly sensitive, selective and stable in electrochemical measurement. In addition, the surface morphology of the Li+/ITO electrode and SnO2 film before and after electrolysis was studied by scanning electron microscopy (SEM) and the percentage of the elements in components was examined by energy dispersive X-ray (EDX). Both of the SEM and EDX evidences that the Li+/ITO electrode and SnO2 film before and after electrolysis are solid to solid conversion

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    Management and 1-year outcomes of patients with newly diagnosed atrial fibrillation and chronic kidney disease: Results from the prospective garfield-af registry

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    Background-—Using data from the GARFIELD-AF (Global Anticoagulant Registry in the FIELD–Atrial Fibrillation), we evaluated the impact of chronic kidney disease (CKD) stage on clinical outcomes in patients with newly diagnosed atrial fibrillation (AF). Methods and Results-—GARFIELD-AF is a prospective registry of patients from 35 countries, including patients from Asia (China, India, Japan, Singapore, South Korea, and Thailand). Consecutive patients enrolled (2013–2016) were classified with no, mild, or moderate-to-severe CKD, based on the National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative guidelines. Data on CKD status and outcomes were available for 33 024 of 34 854 patients (including 9491 patients from Asia); 10.9% (n=3613) had moderate-to-severe CKD, 16.9% (n=5595) mild CKD, and 72.1% (n=23 816) no CKD. The use of oral anticoagulants was influenced by stroke risk (ie, post hoc assessment of CHA2DS2-VASc score), but not by CKD stage. The quality of anticoagulant control with vitamin K antagonists did not differ with CKD stage. After adjusting for baseline characteristics and antithrombotic use, both mild and moderate-to-severe CKD were independent risk factors for all-cause mortality. Moderate-to-severe CKD was independently associated with a higher risk of stroke/systemic embolism, major bleeding, new-onset acute coronary syndrome, and new or worsening heart failure. The impact of moderate-to-severe CKD on mortality was significantly greater in patients from Asia than the rest of the world (P=0.001). Conclusions-—In GARFIELD-AF, moderate-to-severe CKD was independently associated with stroke/systemic embolism, major bleeding, and mortality. The effect of moderate-to-severe CKD on mortality was even greater in patients from Asia than the rest of the world

    Predictors of NOAC versus VKA use for stroke prevention in patients with newly diagnosed atrial fibrillation: Results from GARFIELD-AF

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    Introduction: A principal aim of the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) was to document changes in treatment practice for patients with newly diagnosed atrial fibrillation during an era when non–vitamin K antagonist oral anticoagulants (NOACs) were becoming more widely adopted. In these analyses, the key factors which determined the choice between NOACs and vitamin K antagonists (VKAs) are explored. Methods: Logistic least absolute shrinkage and selection operator regression determined predictors of NOAC and VKA use. Data were collected from 24,137 patients who were initiated on AC ± antiplatelet (AP) therapy (NOAC [51.4%] or VKA [48.6%]) between April 2013 and August 2016. Results: The most significant predictors of AC therapy were country, enrolment year, care setting at diagnosis, AF type, concomitant AP, and kidney disease. Patients enrolled in emergency care or in the outpatient setting were more likely to receive a NOAC than those enrolled in hospital (OR 1.16 [95% CI: 1.04-1.30], OR: 1.15 [95% CI: 1.05-1.25], respectively). NOAC prescribing seemed to be favored in lower-risk groups, namely, patients with paroxysmal AF, normotensive patients, and those with moderate alcohol consumption, but also the elderly and patients with acute coronary syndrome. By contrast, VKAs were preferentially used in patients with permanent AF, moderate to severe kidney disease, heart failure, vascular disease, and diabetes and with concomitant AP. Conclusion: GARFIELD-AF data highlight marked heterogeneity in stroke prevention strategies globally. Physicians are adopting an individualized approach to stroke prevention where NOACs are favored in patients with a lower stroke risk but also in the elderly and patients with acute coronary syndrome
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