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Hooman Kamel - One of the best experts on this subject based on the ideXlab platform.
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machine learning prediction of stroke mechanism in embolic strokes of undetermined source
Stroke, 2020Co-Authors: Hooman Kamel, Peter M Okin, Alexander E Merkler, Babak B Navi, Richard B Devereux, Jonathan W Weinsaft, Jiwon Kim, Neal S Parikh, Jim W Cheung, Luke K KimAbstract:Background and Purpose: One-fifth of ischemic strokes are embolic strokes of undetermined source (Esus). Their theoretical causes can be classified as cardioembolic versus noncardioembolic. This di...
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abstract tp429 arcadia versus other Esus trials comparison of patient characteristics
Stroke, 2020Co-Authors: Carson Van Sanford, Hooman Kamel, Smita Holden, David L Tirschwell, W T Longstreth, Richard A Kronmal, Caitlyn Meinzer, Seemant Chaturvedi, Joseph P Broderick, Mitchell S V ElkindAbstract:Objective: We hypothesize that Esus patients enrolled in the ARCADIA study are broadly representative and similar to those randomized in recent Esus trials that returned negative results. Methods: ...
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relationship between left atrial volume and ischemic stroke subtype
Annals of clinical and translational neurology, 2019Co-Authors: Hooman Kamel, Peter M Okin, Alexander E Merkler, Babak B Navi, Thomas R Campion, Richard B Devereux, Ivan Diaz, Jonathan W Weinsaft, Jiwon KimAbstract:OBJECTIVE Atrial cardiopathy without atrial fibrillation (AF) may be a potential cardiac source of embolic strokes of undetermined source (Esus). Atrial volume is a feature of atrial cardiopathy, but the relationship between atrial volume and Esus remains unclear. METHODS We compared left atrial volume among ischemic stroke subtypes in the Cornell Acute Stroke Academic Registry (CAESAR), which includes all patients with acute ischemic stroke at our hospital since 2011. Stroke subtype was determined by neurologists per the TOAST classification and consensus Esus definition. Left atrial volume index (LAVI) was obtained directly from our echocardiography image system (Xcelera, Philips Healthcare). We used t-tests and analysis of variance for unadjusted comparisons and targeted minimum loss-based estimation for comparisons adjusted for demographics and comorbidities. RESULTS Among 2116 patients in CAESAR from 2011 to 2016, 1293 had LAVI measurements. LAVI varied across subtypes (P < 0.001) from 48.8 (±30.0) mL/m2 in cardioembolic strokes to 30.3 (±10.5) mL/m2 in small-vessel strokes. LAVI was larger in Esus (33.3 ± 13.6 mL/m2 ) than in small- or large-vessel stroke (30.9 ± 10.7 mL/m2 ) (P = 0.01). The association between LAVI and Esus persisted after the adjustment for demographics and comorbidities: a 10 mL/m2 increase in LAVI was associated with a 4.4% increase in Esus probability (95% CI, 2.3%-6.4%). Results were similar after excluding patients with AF during post-discharge heart-rhythm monitoring. INTERPRETATION We found larger left atria among patients with Esus versus non-cardioembolic stroke. There was significant overlap in left atrial size between Esus and non-cardioembolic stroke, highlighting that many Esus cases are not cardioembolic.
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abstract wp264 relationship between left atrial volume and ischemic stroke subtype
Stroke, 2019Co-Authors: Hooman Kamel, Peter M Okin, Richard B Devereux, Jonathan W WeinsaftAbstract:Introduction: Embolic strokes of undetermined source (Esus) are thought to mostly arise from occult cardiac sources or large-artery atherosclerotic lesions. Atrial cardiopathy in the absence of atr...
Navigate Esus Investigators - One of the best experts on this subject based on the ideXlab platform.
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rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source a prespecified subgroup analysis from the navigate Esus trial
Lancet Neurology, 2018Co-Authors: Navigate Esus InvestigatorsAbstract:Background: Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (Esus). Subgroup analyses from previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE Esus trial. Methods: NAVIGATE Esus was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with Esus. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy. Findings: Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22–1·36), and the risk was similar for those without known PFO (1·06; 0·84–1·33; pinteraction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51–8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69–4·70; pinteraction=0·68). The random-effects meta-analysis combined data from NAVIGATE Esus with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24–0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity. Interpretation: Among patients with Esus who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted. Funding: Bayer and Janssen. © 2018 Elsevier Ltd (Less)
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rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source a prespecified subgroup analysis from the navigate Esus trial
Lancet Neurology, 2018Co-Authors: Navigate Esus InvestigatorsAbstract:Summary Background Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (Esus). Subgroup analyses from previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE Esus trial. Methods NAVIGATE Esus was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with Esus. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy. Findings Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22–1·36), and the risk was similar for those without known PFO (1·06; 0·84–1·33; pinteraction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51–8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69–4·70; pinteraction=0·68). The random-effects meta-analysis combined data from NAVIGATE Esus with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24–0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity. Interpretation Among patients with Esus who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted. Funding Bayer and Janssen.
George Ntaios - One of the best experts on this subject based on the ideXlab platform.
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identification of patients with embolic stroke of undetermined source and low risk of new incident atrial fibrillation the af Esus score
International Journal of Stroke, 2021Co-Authors: George Ntaios, Kalliopi Perlepe, Dimitris Lambrou, Gaia Sirimarco, Davide Strambo, Ashraf Eskandari, Efstathia Karagkiozi, Anastasia Vemmou, Eleni KorompokiAbstract:Background and aimsOnly a minority of patients with Embolic Stroke of Undetermined Source (Esus) receive prolonged cardiac monitoring despite current recommendations. The identification of Esus pat...
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potential embolic sources and outcomes in embolic stroke of undetermined source in the navigate Esus trial
Stroke, 2020Co-Authors: George Ntaios, Eleni Korompoki, Scott E Kasner, Mukul Sharma, Roland Veltkamp, Lesly A Pearce, Haralampos J Milionis, Hardi Mundl, Scott D BerkowitzAbstract:Background and Purpose- Emboli in embolic stroke of undetermined source (Esus) may originate from various potential embolic sources (PES), some of which may respond better to anticoagulation, whereas others to antiplatelets. We analyzed whether rivaroxaban is associated with reduction of recurrent stroke compared with aspirin in patients with Esus across different PES and by number of PES. Methods- We assessed the presence/absence of each PES (atrial cardiopathy, atrial fibrillation, arterial atherosclerosis, left ventricular dysfunction, cardiac valvulopathy, patent foramen ovale, cancer) in NAVIGATE-Esus (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source) participants. Prevalence of each PES, as well as treatment effect and risk of event for each PES were determined. Results by number of PES were also determined. The outcomes were ischemic stroke, all-cause mortality, cardiovascular mortality, and myocardial infarction. Results- In 7213 patients (38% women, mean age 67years) followed for a median of 11 months, the 3 most prevalent PES were atrial cardiopathy (37%), left ventricular disease (36%), and arterial atherosclerosis (29%). Forty-one percent of all patients had multiple PES, with 15% having ≥3 PES. None or a single PES was present in 23% and 36%, respectively. Recurrent ischemic stroke risk was similar for rivaroxaban- and aspirin-assigned patients for each PES, except for those with cardiac valvular disease which was marginally higher in rivaroxaban-assigned patients (hazard ratio, 1.8 [95% CI, 1.0-3.0]). All-cause mortality risks were similar across treatment groups for each PES while too few myocardial infarctions and cardiovascular deaths occurred for meaningful assessment. Increasing number of PES was not associated with increased stroke recurrence nor all-cause mortality, and outcomes did not vary between rivaroxaban- and aspirin-assigned patients by number of PES. Conclusions- A large proportion of patients with Esus had multiple PES which could explain the neutral results of NAVIGATE-Esus. Recurrence rates between rivaroxaban- and aspirin-assigned patients were similar across the spectrum of PES. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02313909.
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supraventricular extrasystoles on standard 12 lead electrocardiogram predict new incident atrial fibrillation after embolic stroke of undetermined source the af Esus study
Journal of Stroke & Cerebrovascular Diseases, 2020Co-Authors: George Ntaios, Kalliopi Perlepe, Gaia Sirimarco, Davide Strambo, Ashraf Eskandari, Efstathia Karagkiozi, Anastasia Vemmou, Dimitrios Lambrou, Eleni Koroboki, Efstathios ManiosAbstract:Abstract Background: The diagnosis of covert atrial fibrillation (AF) remains a major challenge to guide secondary prevention of patients with embolic stroke of undetermined source (Esus). Aims: We analyzed consecutive Esus patients from 3 prospective stroke registries to assess whether the presence of supraventricular extrasystoles (SVE) on standard 12-lead electrocardiogram (ECG) is associated with the detection of AF (primary outcome), stroke recurrence and death (secondary outcomes) during follow-up. Methods: We measured the number of SVEs in all available ECGs of patients hospitalized for Esus. Multivariate stepwise regression with forward selection of covariates assessed the association between SVE (classified in 4 groups according to their number per 10 seconds of ECG: no SVE, >0-1SVEs, >1-2SVEs, and >2SVEs) and outcomes during follow-up. The Kaplan–Meier product limit method estimated the 10-year cumulative probabilities of outcomes in each SVE group. We calculated the negative prognostic value (NPV) of the presence of any SVE to predict new AF, defined as the probability that AF will not be detected during follow-up if there is no SVE. Results: Among 853 Esus patients followed for 2857 patient-years (median age: 67 years, 43.0% women), 226 (26.5%) patients had at least 1 SVE at the standard 12-lead ECGs performed during hospitalization. AF was detected in 125 (14.7%) of patients in the overall population during follow-up: 8.9%, 22.5%, 28.1%, and 48.3% in patients with no SVE, greater than 0-1SVE, greater than 1-2SVE and greater than 2SVE respectively. In multivariate regression analysis, compared to patients with no SVEs, the corresponding hazard-ratios were 1.80 [95% confidence intervals (95%CI):1.06-3.05], 2.26 (95%CI:1.28-4.01) and 3.19 (95%CI:1.93-5.27). The NPV of the presence of any SVE for the prediction of new AF was 91.4%. There was no statistically significant association of SVE with the risk of ischemic stroke recurrence and death. Conclusions: In Esus patients without SVEs during hospitalization, the probability that AF will not be detected during a follow-up of 3.4 years is more than 91%.
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predictors of recurrent ischemic stroke in patients with embolic strokes of undetermined source and effects of rivaroxaban versus aspirin according to risk status the navigate Esus trial
Journal of Stroke & Cerebrovascular Diseases, 2019Co-Authors: Robert G Hart, George Ntaios, Sebastian F Ameriso, Scott E Kasner, Mukul Sharma, Ashkan Shoamanesh, Roland Veltkamp, Patrick Sheridan, Shrikant I Bangdiwala, Danilo ToniAbstract:Background: Embolic stroke of undetermined source (Esus) identifies patients with cryptogenic ischemic stroke presumed due to embolism from several unidentified sources. Among patients with recent Esus, we sought to determine independent predictors of recurrent ischemic stroke during treatment with aspirin or rivaroxaban and to assess the relative effects of these treatments according to risk. Methods: Exploratory analyses of 7213 participants in the NAVIGATE Esus international trial who were randomized to aspirin 100 mg/day or rivaroxaban 15 mg/day and followed for a median of 11 months, during which time there were 309 first recurrent ischemic strokes (4.6% per year). Baseline features were correlated with recurrent stroke by multivariate analysis. Results: The 7 independent predictors of recurrent stroke were stroke or transient ischemic attack (TIA) prior to the qualifying stroke (hazard ratio [HR] 2.03 95% confidence internal [CI] 1.58-2.60), current tobacco user (HR 1.62, 95% CI 1.24-2.12), age (HR 1.02 per year increase, 95%CI 1.01-1.03), diabetes (HR 1.28, 95% CI 1.01-1.64), multiple acute infarcts on neuroimaging (HR 1.49, 95% CI 1.09-2.02), aspirin use prior to qualifying stroke (HR 1.34, 95% CI 1.02-1.70), and time from qualifying stroke to randomization (HR .98, 95% CI .97-.99). The rate of recurrent stroke rate was 2.6% per year for participants without any of these risk factors, and increased by an average of 45% for each independent predictor (P < .001). There were no significant interactions between treatment effects and independent stroke predictors or stroke risk status. Conclusions: In this large cohort of Esus patients, several features including prior stroke or TIA, advanced age, current tobacco user, multiple acute infarcts on neuroimaging, and diabetes independently identified those with an increased risk of ischemic stroke recurrence. The relative effects of rivaroxaban and aspirin were similar across the spectrum of independent stroke predictors and recurrent stroke risk status. (Less)
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embolic strokes of undetermined source in the athens stroke registry a descriptive analysis
Stroke, 2015Co-Authors: George Ntaios, Vasileios Papavasileiou, H Milionis, Konstantinos Makaritsis, Efstathios Manios, Konstantinos Spengos, Patrik Michel, Konstantinos VemmosAbstract:Background and Purpose—A new clinical construct termed embolic stroke of undetermined source (Esus) was recently introduced, but no such population has been described yet. Our aim is to provide a detailed descriptive analysis of an Esus population derived from a large prospective ischemic stroke registry using the proposed diagnostic criteria. Methods—The criteria proposed by the Cryptogenic Stroke/Esus International Working Group were applied to the Athens Stroke Registry to identify all Esus patients. Esus was defined as a radiologically confirmed nonlacunar brain infarct in the absence of (a) extracranial or intracranial atherosclerosis causing ≥50% luminal stenosis in arteries supplying the ischemic area, (b) major-risk cardioembolic source, and (c) any other specific cause of stroke. Results—Among 2735 patients admitted between 1992 and 2011, 275 (10.0%) were classified as Esus. In the majority of Esus (74.2%), symptoms were maximal at onset. Esus were of moderate severity (median National Institute ...
Robert G Hart - One of the best experts on this subject based on the ideXlab platform.
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microbleeds and the effect of anticoagulation in patients with embolic stroke of undetermined source an exploratory analysis of the navigate Esus randomized clinical trial
JAMA Neurology, 2021Co-Authors: Ashkan Shoamanesh, Robert G Hart, Scott E Kasner, Robert Mikulik, Stuart J Connolly, Eric E Smith, Joan Martifabregas, Yan Yun Liu, Shinichiro Uchiyama, Roland VeltkampAbstract:Importance The reported associations of cerebral microbleeds with recurrent stroke and intracerebral hemorrhage have raised concerns regarding antithrombotic treatment in patients with a history of stroke and microbleeds on magnetic resonance imaging. Objective To characterize microbleeds in embolic strokes of undetermined source (Esus) and report interactions between microbleeds and the effects of random assignment to anticoagulant vs antiplatelet therapy. Design, setting, and participants Subgroup analyses of the New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial vs Aspirin to Prevent Embolism in Esus (NAVIGATE Esus) international, double-blind, randomized, event-driven phase 3 clinical trial. Participants were enrolled between December 2014 and September 2017 and followed up for a median of 11 months. The study setting included 459 stroke recruitment centers in 31 countries. Patients aged 50 years or older who had neuroimaging-confirmed Esus between 7 days and 6 months before screening were eligible. Of these 7213 NAVIGATE Esus participants, 3699 (51%) had information on cerebral microbleeds reported on their baseline clinical magnetic resonance imaging and were eligible for these analyses. Patients with a prior history of symptomatic intracerebral hemorrhage were excluded from the NAVIGATE Esus trial. Interventions Rivaroxaban, 15 mg, compared with aspirin, 100 mg, daily. Main outcomes and measures The primary outcome was recurrent stroke. Secondary outcomes were ischemic stroke, intracerebral hemorrhage, and all-cause mortality. Results Microbleeds were present in 395 of 3699 participants (11%). Of patients with cerebral microbleeds, mean (SD) age was 69.5 (9.4) years, 241 were men (61%), and 201 were White (51%). Advancing age (odds ratio [OR] per year, 1.03; 95% CI, 1.01-1.04), East Asian race/ethnicity (OR, 1.57; 95% CI, 1.04-2.37), hypertension (OR, 2.20; 95% CI, 1.54-3.15), multiterritorial infarcts (OR, 1.95; 95% CI, 1.42-2.67), chronic infarcts (OR, 1.78; 95% CI, 1.42-2.23), and occult intracerebral hemorrhage (OR, 5.23; 95% CI, 2.76-9.90) were independently associated with microbleeds. The presence of microbleeds was associated with a 1.5-fold increased risk of recurrent stroke (hazard ratio [HR], 1.5; 95% CI, 1.0-2.3), a 4-fold risk of intracerebral hemorrhage (HR, 4.2; 95% CI, 1.3-13.9), a 2-fold risk of all-cause mortality (HR, 2.1; 95% CI, 1.1-4.3), and strictly lobar microbleeds with an approximately 2.5-fold risk of ischemic stroke (HR, 2.3; 95% CI, 1.3-4.3). There were no interactions between microbleeds and treatment assignments for recurrent stroke, ischemic stroke, or all-cause mortality. The HR of intracerebral hemorrhage on rivaroxaban was similar between persons with microbleeds (HR, 3.1; 95% CI, 0.3-30.0) and persons without microbleeds (HR, 3.0; 95% CI, 0.6-14.7; interaction P = .97). Conclusions and relevance Microbleeds mark an increased risk of recurrent stroke, ischemic stroke, intracerebral hemorrhage, and mortality in Esus but do not appear to influence effects of rivaroxaban on clinical outcomes. Trial registration ClinicalTrials.gov Identifier: NCT02313909.
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predictors of recurrent ischemic stroke in patients with embolic strokes of undetermined source and effects of rivaroxaban versus aspirin according to risk status the navigate Esus trial
Journal of Stroke & Cerebrovascular Diseases, 2019Co-Authors: Robert G Hart, George Ntaios, Sebastian F Ameriso, Scott E Kasner, Mukul Sharma, Ashkan Shoamanesh, Roland Veltkamp, Patrick Sheridan, Shrikant I Bangdiwala, Danilo ToniAbstract:Background: Embolic stroke of undetermined source (Esus) identifies patients with cryptogenic ischemic stroke presumed due to embolism from several unidentified sources. Among patients with recent Esus, we sought to determine independent predictors of recurrent ischemic stroke during treatment with aspirin or rivaroxaban and to assess the relative effects of these treatments according to risk. Methods: Exploratory analyses of 7213 participants in the NAVIGATE Esus international trial who were randomized to aspirin 100 mg/day or rivaroxaban 15 mg/day and followed for a median of 11 months, during which time there were 309 first recurrent ischemic strokes (4.6% per year). Baseline features were correlated with recurrent stroke by multivariate analysis. Results: The 7 independent predictors of recurrent stroke were stroke or transient ischemic attack (TIA) prior to the qualifying stroke (hazard ratio [HR] 2.03 95% confidence internal [CI] 1.58-2.60), current tobacco user (HR 1.62, 95% CI 1.24-2.12), age (HR 1.02 per year increase, 95%CI 1.01-1.03), diabetes (HR 1.28, 95% CI 1.01-1.64), multiple acute infarcts on neuroimaging (HR 1.49, 95% CI 1.09-2.02), aspirin use prior to qualifying stroke (HR 1.34, 95% CI 1.02-1.70), and time from qualifying stroke to randomization (HR .98, 95% CI .97-.99). The rate of recurrent stroke rate was 2.6% per year for participants without any of these risk factors, and increased by an average of 45% for each independent predictor (P < .001). There were no significant interactions between treatment effects and independent stroke predictors or stroke risk status. Conclusions: In this large cohort of Esus patients, several features including prior stroke or TIA, advanced age, current tobacco user, multiple acute infarcts on neuroimaging, and diabetes independently identified those with an increased risk of ischemic stroke recurrence. The relative effects of rivaroxaban and aspirin were similar across the spectrum of independent stroke predictors and recurrent stroke risk status. (Less)
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secondary stroke prevention in cryptogenic stroke and embolic stroke of undetermined source Esus
Current Neurology and Neuroscience Reports, 2017Co-Authors: Hanschristoph Diener, Richard A Bernstein, Robert G HartAbstract:The purpose of the study was to review the literature on cryptogenic stroke and embolic stroke of undetermined stroke (Esus). Cryptogenic stroke according to TOAST criteria is a stroke which is not due to cardiogenic embolism, small vessel disease with lacunes or large vessel disease of brain supplying arteries. In the context of secondary stroke prevention studies, cryptogenic stroke is not operationally defined. The new concept of “embolic stroke of undetermined source” (Esus) provides an operational definition. Esus is diagnosed as a non-lacunar stroke on cerebral imaging and exclusion of large vessel atherosclerosis by CTA, MRA or ultrasound. Cardiogenic embolism is made less likely by ECG monitoring and echocardiography. At present, aspirin is used for secondary stroke prevention in patients with cryptogenic stroke. Based on the construct that Esus might be caused by undetected atrial fibrillation or other embolic mechanisms, ongoing randomised secondary stroke prevention trials are comparing non-vitamin K oral anticoagulants (NOACs) with aspirin.
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abstract t mp53 frequency aad features of patients with embolic strokes of underdetermined source Esus Esus global registry
Stroke, 2015Co-Authors: Antonio Arauz, Thomas Vanassche, Jackie Bosch, Phillippa Lavallee, Luis Cunha, Peter A Ringleb, Rubens J Gagliardi, Robert G HartAbstract:Background: Embolic stroke of undetermined source (Esus) is a recently introduced clinical construct to define non-lacunar cryptogenic ischemic stroke and is the basis for two large international randomized trials recently underway. Diagnostic criteria are a visualized non-lacunar stroke on CT or MRI, absence of atrial fibrillation by history, ECG and at least 24 hours of rhythm monitoring, absence of intracardiac thrombus by echocardiography, no occlusive atherosclerosis based on imaging of the cervical and intracranial arteries, and no specific cause of stroke identified. The frequency and features of Esus patients have not been characterized previously. Methods: Consecutive patients with recent ischemic stroke were retrospectively reviewed at 20 stroke research centers in 20 different countries to identify those meeting criteria for Esus, as well as reasons not meeting criteria for the remaining patients. Results: Of 2.090 patients with recent ischemic stroke, 18% met Esus criteria (range 2% to 36%). Of those not meeting Esus criteria, major reasons were atrial fibrillation (26%), lacunar stroke (19%), incomplete diagnostic evaluation (18%), carotid artery stenosis >50% (17%), and intracranial stenosis (13%). Excluding those without the required diagnostic evaluation, 22% met criteria for Esus. Of the 378 Esus patients, the mean age was 64 years (vs. 68 years for non-Esus), 56% were men (54% non-Esus), 16% received tPA, and 33% were taking antiplatelet therapy at stroke onset. Hypertension, diabetes, and coronary artery disease were present in 66%, 26%, and 11%, respectively. At hospital discharge, 93% received antiplatelet therapy, 6% anticoagulant therapy, and 1% no antithrombotic therapy. Conclusions: Ischemic stroke patients meeting criteria for Esus are not uncommon (22% of ischemic strokes) in stroke centers performing the required diagnostic evaluation. Antiplatelet therapy is overwhelmingly used for secondary prevention in these patients with non-lacunar cryptogenic stroke.
Mohammad Ashiqur Rahman - One of the best experts on this subject based on the ideXlab platform.
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Blockchain-Based Charging Coordination Mechanism for Smart Grid Energy Storage Units
2019 IEEE International Conference on Blockchain (Blockchain), 2019Co-Authors: Mohamed Baza, Mahmoud Nabil, Erchin Serpedin, Muhammad Ismail, Mohamed Mahmoud, Mohammad Ashiqur RahmanAbstract:Energy storage units (Esus) enable several attractive features of modern smart grids such as enhanced grid resilience, effective demand response, and reduced bills. However, uncoordinated charging of Esus stresses the power system and can lead to a blackout. In this paper, we leverage the blockchain and smart contracts to build a decentralized charging coordination mechanism without the need for a centralized charging coordinator. First Esus should use tokens for anonymously authenticate themselves to the blockchain. Then each ESU sends a charging request that contains its State-of-Charge (SoC), Time-to-complete-charge (TCC) and amount of required charging to the smart contract address on the blockchain. The smart contract will then run the charging coordination mechanism in a self-executed manner such that Esus with the highest priorities are charged in the present time slot while charging requests of lower priority Esus are deferred to future time slots. In this way, each ESU can make sure that charging schedules are computed correctly. Finally, we have implemented the proposed mechanism on the Ethereum test-bed blockchain, and our analysis shows that execution cost can be acceptable in terms of gas consumption while enabling decentralized charging coordination with increased transparency, reliability, and privacy preserving.
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Blockchain-based Charging Coordination Mechanism for Smart Grid Energy Storage Units.
arXiv: Cryptography and Security, 2018Co-Authors: Mohamed Baza, Mahmoud Nabil, Erchin Serpedin, Muhammad Ismail, Mohamed Mahmoud, Mohammad Ashiqur RahmanAbstract:Energy storage units (Esus) enable several attractive features of modern smart grids such as enhanced grid resilience, effective demand response, and reduced bills. However, uncoordinated charging of Esus stresses the power system and can lead to a blackout. On the other hand, existing charging coordination mechanisms suffer from several limitations. First, the need for a central charging coordinator (CC) presents a single point of failure that jeopardizes the effectiveness of the charging coordination. Second, a transparent charging coordination mechanism does not exist where users are not aware whether the CC is honest or not in coordination charging requests among them in a fair way. Third, existing mechanisms overlook the privacy concerns of the involved customers. To address these limitations, in this paper, we leverage the blockchain and smart contracts to build a decentralized charging coordination mechanism without the need for a centralized charging coordinator. First Esus should use tokens for anonymously authenticate themselves to the blockchain. Then each ESU sends a charging request that contains its State-of-Charge (SoC), Time-to-complete-charge (TCC) and amount of required charging to the smart contract address on the blockchain. The smart contract will then run the charging coordination mechanism in a self-executed manner such that Esus with the highest priorities are charged in the present time slot while charging requests of lower priority Esus are deferred to future time slots. In this way, each ESU can make sure that charging schedules are computed correctly. Finally, we have implemented the proposed mechanism on the Ethereum test-bed blockchain, and our analysis shows that execution cost can be acceptable in terms of gas consumption while enabling decentralized charging coordination with increased transparency, reliability, and privacy preserving.
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Blockchain-based Privacy-Preserving Charging Coordination Mechanism for Energy Storage Units.
2018Co-Authors: Mohamed Baza, Mahmoud Nabil, Erchin Serpedin, Muhammad Ismail, Mohamed Mahmoud, Mohammad Ashiqur RahmanAbstract:Energy storage units (Esus) enable several attractive features of modern smart grids such as enhanced grid resilience, effective demand response, and reduced bills. However, uncoordinated charging of Esus stresses the power system and can lead to mass blackout. On the other hand, existing charging coordination mechanisms suffer from several limitations. First, the need for a central charging controller (CC) presents a single point of failure that jeopardizes the effectiveness of the charging coordination. Second, existing mechanisms overlook privacy concerns of the involved customers. To address these limitations, in this paper, we leverage the blockchain and smart contracts to build a decentralized charging coordination mechanism without the need for centralized charging coordinator. After each ESU sends a charging request to the smart contract address on the blockchain, the smart contract will run the charging coordination mechanism in a self-executed manner such that Esus with the highest priority are charged in the present time slot while charging requests of lower priority Esus are deferred to future time slots. We have implemented the proposed mechanism on the Ethereum blockchain and our analysis shows that the blockchain enables a decentralized charging coordination with increased transparency, reliability, and privacy preservation.