Evaluation of risk stratification schemes for ischaemic stroke and bleeding in 182 678 patients with atrial fibrillation: the Swedish Atrial Fibrillation cohort study. Focused 2012 update of the Canadian Cardiovascular Society atrial fibrillation guidelines: recommendations for stroke prevention and rate/rhythm control. Stroke due to atrial fibrillation in a population-based stroke registry (Ludwigshafen Stroke Study) CHADS(2) , CHA(2) DS(2) -VASc score, underuse of oral anticoagulation, and implications for preventive measures. Transesophageal echocardiographic correlates of thromboembolism in high-risk patients with nonvalvular atrial fibrillation. The Stroke Prevention in Atrial Fibrillation Investigators Committee on Echocardiography. Assessment of three schemes for stratifying stroke risk in patients with nonvalvular atrial fibrillation. Feasibility of TEE-guided stroke risk assessment in atrial fibrillation—background, aims, design and baseline data of the TIARA pilot study Increased risk of first-ever stroke in younger patients with atrial fibrillation not recommended for antithrombotic therapy by current guidelines: a population-based study in an East Asian cohort of 22 million people. Acute stroke with atrial fibrillation. The Copenhagen Stroke Study. A randomised controlled trial and cost effectiveness study of systematic screening (targeted and total population screening) versus routine practice for the detection of atrial fibrillation in the over 65s: (SAFE) [ISRCTN19633732] Performance of stroke risk scores in older people with atrial fibrillation not taking warfarin: comparative cohort study from BAFTA trial Epidemiology of ischemic stroke from atrial fibrillation in Dijon, France, from 1985 to 2006 Prevalence, clinical profile, and cardiovascular outcomes of atrial fibrillation patients with atherothrombosis. Atrial Fibrillation Is a Major Risk Factor for Stroke, Especially in Women: The Jichi Medical School Cohort Study Rationale and design of the Apixaban for the Reduction of Thrombo‐Embolism in Patients With Device‐Detected Sub‐Clinical Atrial Fibrillation (ARTESiA) trial Stroke event rates in anticoagulated patients with paroxysmal atrial fibrillation. Atrial fibrillation and risk of dementia: a prospective cohort study. Probing oral anticoagulation in patients with atrial high rate episodes: Rationale and design of the Non–vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH–AFNET 6) trial
AIMS The impact of some risk factors for stroke and bleeding , and the value of stroke and bleeding risk scores , in atrial fibrillation ( AF ) , has been debated , as clinical trial cohorts have not adequately tested these . Our objective was to investigate risk factors for stroke and bleeding in AF , and application of the new CHA(2)DS(2)-VASc and HAS-BLED schemes for stroke and bleeding risk assessment s , respectively . METHODS AND RESULTS We used the Swedish Atrial Fibrillation cohort study , a nationwide cohort study of 182 678 subjects with a diagnosis of AF at any Swedish hospital between 1 July 2005 and 31 December 2008 , who were prospect ively followed for an average of 1.5 years ( 260 000 years at risk ) . With the use of the National Swedish Drug Registry , all patients who used an oral anticoagulant  anytime during follow-up were identified . Most of the analyses were made on a subset of 90 490 patients who never used anticoagulants .  Risk factors for stroke , the composite thromboembolism endpoint ( stroke , TIA , or systemic embolism ) , and bleeding , and the performance of published stroke and bleeding risk stratification schemes were investigated . On multivariable analysis , significant associations were found between the following ' new ' risk factors and thromboembolic events ; peripheral artery disease [ hazard ratio ( HR ) 1.22 ( 95 % CI 1.12 - 1.32 ) ] , ' vascular disease ' [ HR 1.14 ( 1.06 - 1.23 ) ] , prior myocardial infa rct ion [ HR 1.09 ( 1.03 - 1.15 ) ] , and female gender [ HR 1.17 ( 1.11 - 1.22 ) ] . Previous embolic events , intracranial haemorrhage ( ICH ) , hypertension , diabetes , and renal failure were other independent predictors of the composite thromboembolism endpoint , while thyroid disease ( or hyperthyroidism ) was not an independent stroke risk factor . C-statistics for the composite thromboembolic endpoint with the CHADS(2 ) and CHA(2)DS(2)-VASc schemes were 0.66 ( 0.65 - 0.66 ) and 0.67 ( 0.67 - 0.68 ) , respectively . On multivariable analysis , age , prior ischaemic stroke or thromboembolism , prior major bleeding events , and hypertension were significant predictors of ICH and major bleeding . Heart failure , diabetes , renal failure , liver disease , anaemia or platelet/coagulation defect , alcohol abuse , and cancer were other significant predictors for major bleeding , but not ICH . The ability for predicting ICH and major bleeding with both bleeding risk schemes ( HEMORR(2)HAGES , HAS-BLED ) were similar , with c-statistics of ~0.6 . CONCLUSION Several independent risk factors ( prior ICH , myocardial infa rct ion , vascular disease , and renal failure ) predict ischaemic stroke and /or the composite thromboembolism endpoint in AF , but thyroid disease ( or hyperthyroidism ) was not an independent risk factor for stroke . There is a better performance for CHA(2)DS(2)-VASc over CHADS(2 ) schemes for the composite thromboembolism endpoint . While both tested bleeding risk schemes have similar predictive value , the HAS-BLED score has the advantage of simplicity The Canadian Cardiovascular Society ( CCS ) published the complete set of 2010 Atrial Fibrillation ( AF ) Guidelines in the January , 2011 issue of the Canadian Journal of Cardiology . During its deliberations , the CCS Guidelines Committee engaged to a timely review of future evidence , with periodic composition of focused up date s to address clinical ly important advances . In 2011 , results were published from 3 pivotal AF trials : the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonist for Prevention of Stroke and Embolism Trial in Atrial Fibrillation ( ROCKET-AF ) , the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation ( ARISTOTLE ) study , and the Permanent Atrial Fibrillation Outcome Study Using Dronedarone on Top of St and ard Therapy ( PALLAS ) , comparing dronedarone with placebo in patients with permanent AF and additional cardiovascular disease risk-factor burden . Each of these large r and omized trials provided clear results with major implication s for AF management . Other important evidence that has emerged since the 2010 Guidelines includes findings about prediction instruments for AF-associated stroke and bleeding risk , stroke risk in paroxysmal-AF patients , risk-benefit considerations related to oral anticoagulation in patients with chronic kidney disease , and risk/benefit considerations in the use of antiplatelet agents , alone and in combination with each other or with oral anticoagulants , in AF patients . The Guidelines Committee judged that this extensive and important new evidence required focused updating of the 2010 Guidelines with respect to stroke prevention and rate/rhythm control . This report presents the details of the new recommendations , along with the background and rationale BACKGROUND AND PURPOSE Atrial fibrillation ( AF ) is amongst the most important etiologies of ischaemic stroke . In a population -based stroke registry , we tested the hypothesis of low adherence to current guidelines as a main cause of high rates of AF-associated stroke . METHODS Within the Ludwigshafen Stroke Study ( LuSSt ) , a prospect i ve ongoing population -based stroke register , we analyzed all patients with a first-ever ischaemic stroke ( FEIS ) owing to AF in 2006 and 2007 . We determined whether AF was diagnosed before stroke and assessed pre-stroke CHADS(2 ) and CHA(2 ) DS(2 ) -VASc scores . RESULTS In total , 187 of 626 patients with FEIS suffered from cardioembolic stroke owing to AF , which was newly diagnosed in 57 ( 31 % ) patients . Retrospective pre-stroke risk stratification according to CHADS(2 ) score indicated low/intermediate risk in 34 patients ( 18 % ) and high risk ( CHADS(2 ) ≥ 2 ) in 153 patients ( 82 % ) . Application of CHA(2 ) DS(2 ) -VASc score reduced number of patients at low/intermediate risk ( CHA(2 ) DS(2 ) -VASc score 0 - 1 ) to five patients ( 2.7 % ) . In patients with a CHADS(2 ) score ≥ 2 and known AF ( n = 106 ) before stroke , 38 ( 36 % ) were on treatment with vitamin K antagonists on admission whilst only in 16 patients ( 15 % ) treatment was in therapeutic range . CONCLUSIONS Our study strongly supports the hypothesis that underuse of oral anticoagulants in high-risk patients importantly contributes to AF-associated stroke . CHA(2 ) DS(2 ) -VASc score appears to be a more valuable risk stratification tool than CHADS(2 ) score . Preventive measures should focus on optimizing pre-stroke detection of AF and better implementation of present AF- guidelines with respect to anticoagulation therapy The risk for ischemic stroke in patients with atrial fibrillation is related to underlying structural heart disease [ 1 - 3 ] . Although most strokes are believed to arise from embolism of left atrial thrombi [ 4 , 5 ] , other mechanisms may contribute . Transesophageal echocardiography ( TEE ) provides a unique diagnostic window for evaluating the left atrium , left atrial appendage , and thoracic aorta , but the manner in which specific TEE findings in patients with atrial fibrillation correlate with thromboembolic risk and response to therapy has not been fully established [ 6 - 13 ] . We performed TEE in patients with nonvalvular atrial fibrillation who were at high intrinsic risk for thromboembolism and were participating in the Stroke Prevention in Atrial Fibrillation ( SPAF-III ) study , a r and omized clinical trial . In that study , adjusted-dose warfarin ( target international normalized ratio [ INR ] , 2 to 3 ) was compared with combination therapy consisting of low-intensity warfarin ( INR , 1.2 to 1.5 ) plus aspirin , 325 mg/d . The trial was stopped after an interim analysis indicated that the efficacy of adjusted-dose warfarin therapy was superior to that of combination therapy . Low anticoagulation intensity in the combination therapy group yielded high stroke rates that were similar to those expected during treatment with aspirin alone [ 14 , 15 ] . In the current analysis , we 1 ) correlate TEE observations among patients with atrial fibrillation at high risk for thromboembolism with rate of subsequent stroke and 2 ) compare treatment responses . Methods Patients Patients were recruited from the SPAF-III multicenter trial , which was design ed to compare two antithrombotic medication regimens for prevention of ischemic stroke and systemic embolism ( primary events ) . The study , whose design is described else-where in detail [ 14 ] , involved patients with nonvalvular atrial fibrillation who were stratified for risk on the basis of clinical and transthoracic echocardiographic criteria derived from previous analyses [ 15 ] . Women older than 75 years of age and patients of any age and either sex with systolic hypertension ( systolic blood pressure > 160 mm Hg ) , previous thromboembolism , or impaired left ventricular function ( M-mode echocardiographic fractional shortening of 0.25 or recent clinical congestive heart failure ) were r and omly assigned to receive adjusted-dose warfarin ( target INR , 2.0 to 3.0 ) or a combination of low-intensity warfarin ( 0.5 to 3.0 mg/d ; dose was initially adjusted to cause deviation of the INR to 1.2 to 1.5 and was then fixed ) and aspirin . Seventy-three percent of the patients were receiving warfarin at various dose intensities before trial entry ; these patients were equally distributed between assigned treatment groups . Antithrombotic treatment was assigned before performance of TEE and was not influenced by TEE findings . Patients were followed monthly by telephone and in clinic every 3 months , and a st and ard question naire on stroke symptoms was administered annually . All patients whose responses to the question naire suggested the occurrence of stroke were referred for clinical examination by a local affiliated neurologist who was blinded to treatment , and all events were adjudicated by a blinded event verification committee [ 14 ] . This project was design ed to supplement the SPAF-III clinical trial on the basis of the hypothesis that spontaneous echocardiographic contrast detected by TEE identifies patients at high risk for thromboembolism for whom adjusted-dose warfarin  would prove superior to  combination therapy . All participants in the parent study were encouraged , but not required , to provide separate , written informed consent for TEE after r and om assignment to antithrombotic treatment . This was done to prevent the results of TEE from influencing recruitment of patients into the trial or from altering treatment . The intended sample size of 412 TEE examinations was selected to detect an absolute difference in event rates of 3.9 % per year ( based on projected event rates of 5.4 % per year in patients with spontaneous echocardiographic contrast and 1.5 % per year in patients without contrast ) over a mean observation period of 2.5 years . Secondary objectives were to correlate clinical thromboembolic events with function of the left atrial appendage , thrombus of the left atrium and left atrial appendage , and atherosclerotic lesions in the thoracic aorta imaged by TEE . Transesophageal Echocardiography Transesophageal echocardiography was performed within 3 months of enrollment with patients under light sedation and topical anesthesia , according to specific protocol s for acquisition and interpretation [ 16 ] . Commercially available ultrasonography equipment incorporated biplane or multiplane transducers with at least 48 crystals operating at a st and ard frequency of 5 MHz with gray-scale imaging . Signal processing , log compression , and persistence values were established for each manufacturer . Images were interpreted locally , and data were entered into st and ardized forms by echocardiographers who were blinded to antithrombotic treatment assignment but not to patient demographic or clinical features . Original videotaped recordings were collected in a central echocardiographic registry for validation and quality control . To assure generalizability of the results to laboratories used in clinical practice , the analyses reported here are based on image interpretation at the local laboratories . The following features were specifically assessed : left atrial appendage size , peak ante grade ( emptying ) velocity of blood flow in the left atrial appendage , spontaneous echocardiographic contrast in the left atrium or left atrial appendage , thrombus of the left atrium or left atrial appendage , and atherosclerotic disease of the thoracic aorta . Spontaneous echocardiographic contrast was defined as a pattern of slowly swirling intracavitary echodensities imaged with gain setting s adjusted to distinguish background noise . Contrast was classified as faint when visualized intermittently during the cardiac cycle or when enhanced gain setting s were required for detection and was classified as dense when continuously present at st and ard gain . Aortic plaque was classified by location and as either simple or complex according to mobility , ulceration , pedunculation , or thickness greater than 4 mm [ 16 ] . We postulated that reduced emptying velocity from the left atrial appendage , which reflects stasis , would be associated with dense spontaneous echocardiographic contrast and thrombus formation , whereas complex aortic plaque would be a consequence of atherosclerotic vascular abnormality . We also postulated that these findings would predispose patients to ischemic stroke through separate pathogenic mechanisms . Statistical Analysis The analyses reported here were limited to variables accessible only by TEE and were hypothesized a priori to have potential predictive relations to clinical thromboembolism . Baseline comparisons between groups were done by using the chi-square test for categorical data and the Student t-test for continuous variables . The Cox proportional-hazards regression model was used to estimate the univariate relative risk associated with TEE characteristics . The primary analysis compared rates of cerebral ischemic events and systemic embolism among patients who had dense spontaneous echocardiographic contrast detected in the left atrium or left atrial appendage with rates in patients who did not have dense contrast ; the log-rank statistic was used to compare the times to events between these groups . Secondary analyses , conducted similarly , compared event rates in groups that were identified by left atrial appendage size , flow velocity , thrombus , and aortic plaque . For these comparisons , the area of the left atrial appendage was dichotomized at the upper quartile ; flow velocity was dichotomized at the lower quartile . When interaction was seen between treatment and TEE characteristics , analysis of the relation of TEE findings to events was confined to the combination therapy group and treatment effect was described separately ; when no interaction was seen , the analysis was stratified by therapy . The relative reduction in event rate associated with adjusted-dose warfarin therapy was computed as the difference between unity and the rate ratio determined by a Poisson regression model [ 17 ] . A Cox proportional-hazards regression model was fit to confirm the independence of TEE characteristics identified as univariate thromboembolic risk factors . Confidence intervals for event rates were calculated by using a Poisson regression model ; tests of significance were two-sided and were not adjusted for multiple comparisons . All analyses were done according to the intention-to-treat principle . Results Of 1044 high-risk patients with atrial fibrillation enrolled in the r and omized trial , 382 ( 37 % ) volunteered for TEE ( range , 10 % to 80 % of SPAF-III participants recruited at 18 clinical centers offering TEE ) . Salient features of these 382 patients were similar to those of the 662 participants who did not undergo transesophageal imaging ( Table 1 ) . The mean patient age was 71 years , 36 % of patients had clinical ischemic heart disease , and almost half had a history of congestive heart failure . Balanced proportions of patients were assigned to therapy with adjusted-dose warfarin ( n = 190 ) or fixed-dose warfarin and aspirin ( n = 192 ) . Time from r and om assignment of treatment to TEE was similar in the two groups ( mean , 23 days ) . The trial was stopped after a mean observation period of 1.1 years because an interim analysis indicated the lack of efficacy of the combination regimen [ 18 ] . Up to that point , 23 primary events ( all of which were ischemic strokes ) occurred in the subset of participants who had undergone TEE ( event rate , 3.1 % per year in patients assigned to adjusted-dose warfarin compared with 7.8 % per year in those assigned to combination therapy ; P = 0.04 ) . PURPOSE The risk of ischemic stroke varies widely among patients with nonvalvular atrial fibrillation , influencing the choice of prophylactic antithrombotic therapy . We assessed three schemes for stroke risk stratification in these patients who were treated with aspirin and who did not have prior cerebral ischemia . SUBJECTS AND METHODS Criteria from three schemes of risk stratification were applied to a longitudinally observed cohort of patients with atrial fibrillation who did not have prior cerebral ischemia and who were treated with aspirin alone or aspirin combined with low , ineffective doses of warfarin in a multicenter clinical trial . The ability of the schemes to identify patients at high ( > /=6 % ) , low ( < /=2 % ) , and intermediate annual risks of ischemic stroke was assessed . RESULTS During a mean follow-up of 1.8 years , 48 ischemic strokes occurred among 1,073 patients with atrial fibrillation who were taking aspirin ( rate = 2.5 per 100 person-years ) . Each of the three schemes predicted stroke and disabling stroke , and successfully identified patients at low risk ( observed stroke rates of 0.3 to 1.1 per 100 person-years ) , although the fractions of the cohort that were categorized as low risk varied from 14 % to 45 % . The observed rates of ischemic stroke among patients categorized as high risk ranged from 3.5 to 7.2 per 100 person-years among the stratification schemes . Two schemes considered all patients > 75 years old as high risk ( observed stroke rate 4.2 per 100 person-years ) , while the remaining scheme classified one third of patients in this age group as low risk ( observed stroke rate 0.6 per 100 person-years ) . CONCLUSIONS When tested in a large cohort of patients with atrial fibrillation who were treated with aspirin  , available risk-stratification schemes successfully identified patients with low rates of ischemic stroke , but less consistently identified high-risk patients Background Antithrombotic management in atrial fibrillation ( AF ) is currently based on clinical characteristics , despite evidence of potential fine-tuning with transoesophageal echocardiography ( TEE ) . This open , r and omised , multicentre study addresses the hypothesis that a comprehensive strategy of TEE-based aspirin treatment in AF patients is feasible and safe . Methods Between 2005 and 2009 , ten large hospitals in the Netherl and s enrolled AF patients with a moderate risk of stroke . Patients without thrombogenic TEE characteristics were r and omised to aspirin or vitamin K antagonists ( VKA ) . The primary objective is to show that TEE-based aspirin treatment is safe compared with VKA therapy . The secondary objective tests feasibility of TEE as a tool to detect echocardiographic features of high stroke risk . This report compares r and omised to non-r and omised patients and describes the feasibility of a TEE-based approach . Results In total , 310 patients were included . Sixty-nine patients were not r and omised because of non-visualisation ( n = 6 ) or TEE risk factors ( n = 63 ) . Compared with non-r and omised patients , r and omised patients ( n = 241 ) were younger ( 65 ± 11 vs. 69 ± 9 years , p = 0.004 ) , had less  coronary artery disease ( 9 vs. 20 % , p = 0.018 ) , previous TIA ( 1.7 vs. 7.2 % , p = 0.029 ) , AF during TEE ( 25 vs. 54 % , p < 0.001 ) , mitral incompetence ( 55 vs. 70 % , p = 0.038 ) , VKA use ( 69 vs. 82 % , p = 0.032 ) , had a lower mean CHADS2 score ( 1.2 ± 0.6 vs. 1.6 ± 1.0 , p = 0.004 ) , and left ventricular ejection fraction ( 59 ± 8 vs. 56 ± 8 % , p = 0.016 ) . Conclusions This study shows that a TEE-based approach for fine-tuning stroke risk in AF patients with a moderate risk for stroke is feasible . Follow-up data will address the safety of this TEE-based approach OBJECTIVE To assess the risk of first-ever ischemic stroke in younger patients with atrial fibrillation ( AF ) who have none of the CHA2DS2-VASc ( congestive heart failure , hypertension , age ≥75 years , diabetes mellitus , previous stroke/transient ischemic attack , vascular disease , age 65 - 74 years , sex category [ female sex ] ) risk factors ( excluding female sex ) by using the National Health Insurance research data base in Taiwan . PATIENTS AND METHODS From 22,842,778 insured people , we identified 24,612 hospitalized patients with newly diagnosed AF between January 1 , 2002 , and December 31 , 2004 , as the AF group and r and omly selected 98,448 age- and sex-matched persons without AF as the non-AF group . Both groups were followed up until December 31 , 2010 , to estimate ischemic stroke incidences in relation to other stroke risk factors . RESULTS During a follow-up period of 89,468 person-years , the stroke rate was higher in patients with AF than in those without AF ( 5.79 per 100 person-years vs 2.25 per 100 person-years ) . The higher prevalence of CHA2DS2-VASc comorbidities ( heart failure , hypertension , diabetes , coronary artery disease , and peripheral artery disease ) in patients with AF further increased the stroke risk . In 790 patients with AF aged 30 to 55 years who had none of the CHA2DS2-VASc comorbidities at baseline and retained a " low risk , " that is , those with a CHA2DS2-VASc score of 0 in men and 1 in women during follow-up , the stroke rate remained considerably higher than that in their non-AF counterparts ( 1.00 per 100 person-years vs 0.25 per 100 person-years ) , with a sex-adjusted hazard ratio of 4.09 ( 95 % CI , 2.97 - 5.62 ) . CONCLUSION This study finds an increased risk of stroke in younger patients with AF who are not recommended for prevention of thromboembolism by current guidelines . Better stroke risk stratification tools are needed to prioritize younger patients with AF for thromboprophylactic therapy in this population BACKGROUND Atrial fibrillation ( AF ) is a common arrhythmia and a major risk factor for stroke . Many physicians remain reluctant to provide stroke prevention by anticoagulant therapy especially for elderly individuals with AF . Using multivariate regression analyses , we studied the characteristics and the prognosis of stroke in patients with AF . METHODS The study is part of the Copenhagen Stroke Study , a prospect i ve , community-based study of 1197 patients with acute stroke treated on a stroke unit from the time of acute admission to the end of rehabilitation .  Initial stroke severity was measured by the Sc and inavian Neurological Stroke Scale ( SSS ) . Neurological and functional outcomes were evaluated by the SSS and the Barthel Index . RESULTS AF was diagnosed in 18 % of the patients . AF increased steeply with age in the stroke population , from 2 % in patients < 50 years old , 15 % in patients in their 70s , and 28 % in patients in their 80s , to 40 % in patients > or = 90 years of age . In a multivariate analysis AF was associated with age ( odds ratio [ OR ] , 2.0 per 10-year increase ; 95 % confidence ratio [ CI ] , 1.6 to 2.6 ) , ischemic heart disease ( OR , 3.4 ; 95 % CI , 2.4 to 4.8 ) , previous stroke ( OR , 1.8 ; 95 % CI , 1.2 to 2.6 ) , and systolic blood pressure ( OR , 0.93 per 10-mm Hg increases ; 95 % CI , 0.88 to 0.99 ) , but not with sex , diabetes , hypertension , previous transient ischemic attack , or silent infa rct ion on computed tomography . Patients with AF had a higher mortality rate ( OR , 1.7 ; 95 % CI , 1.2 to 2.5 ) , longer hospital stays ( 50 days versus 40 days , P < .001 ) , and a lower discharge rate to their own homes ( OR , 0.60 ; 95 % CI , 0.44 to 0.85 ) . Neurological and functional outcomes were markedly poorer in patients with AF . Poorer outcome was exclusively explained by initially more-severe strokes . CONCLUSIONS Stroke in patients with AF is generally more severe and outcome markedly poorer than in patients with sinus rhythm . This accentuates the importance of anticoagulant treatment of individuals with AF . A lower blood pressure in the acute stage of stroke may contribute to the increased stroke severity in patients with AF Background Atrial fibrillation ( AF ) has been recognised as an important independent risk factor for thromboembolic disease , particularly stroke for which it provides a five-fold increase in risk . This study aim ed to determine the baseline prevalence and the incidence of AF based on a variety of screening strategies and in doing so to evaluate the incremental cost-effectiveness of different screening strategies , including targeted or whole population screening , compared with routine clinical practice , for detection of AF in people aged 65 and over . The value of clinical assessment and echocardiography as additional methods of risk stratification for thromboembolic disease in patients with AF were also evaluated . Methods The study design was a multi-centre r and omised controlled trial with a study population of patients aged 65 and over from 50 General Practice s in the West Midl and s. These purpose fully selected general practice s were r and omly allocated to 25 intervention practice s and 25 control practice s. GPs and practice nurses within the intervention practice s received education on the importance of AF detection and ECG interpretation . Patients in the intervention practice s were r and omly allocated to systematic ( n = 5000 ) or opportunistic screening ( n = 5000 ) . Prospect i ve identification of pre-existing risk factors for AF within the screened population enabled comparison between high risk targeted screening and total population screening . AF detection rates in systematic ally screened and opportunistically screened population s in the intervention practice s were compared to AF detection rate in 5,000 patients in the control practice Objective To compare the predictive power of the main existing and recently proposed schemes for stratification of risk of stroke in older patients with atrial fibrillation . Design Comparative cohort study of eight risk stratification scores . Setting Trial of thromboprophylaxis in stroke , the Birmingham Atrial Fibrillation in the Aged ( BAFTA ) trial . Participants 665 patients aged 75 or over with atrial fibrillation based in the community who were r and omised to the BAFTA trial and were not taking warfarin throughout or for part of the study period . Main outcome measures Events rates of stroke and thromboembolism . Results 54 ( 8 % ) patients had an ischaemic stroke , four ( 0.6 % ) had a systemic embolism , and 13 ( 2 % ) had a transient ischaemic attack . The distribution of patients classified into the three risk categories ( low , moderate , high ) was similar across three of the risk stratification scores ( revised CHADS2 , NICE , ACC/AHA/ESC ) , with most patients categorised as high risk ( 65 - 69 % , n=460 - 457 ) and the remaining classified as moderate risk . The original CHADS2 ( Congestive heart failure , Hypertension , Age ≥75 years , Diabetes , previous Stroke ) score identified the lowest number as high risk ( 27 % , n=180 ) . The incremental risk scores of CHADS2 , Rietbrock modified CHADS2 , and CHA2DS2-VASc ( CHA2DS2-Vascular disease , Age 65 - 74 years , Sex ) failed to show an increase in risk at the upper range of scores . The predictive accuracy was similar across the tested schemes with C statistic ranging from 0.55 ( original CHADS2 ) to 0.62 ( Rietbrock modified CHADS2 ) , with all except the original CHADS2 predicting better than chance . Bootstrapped paired comparisons provided no evidence of significant differences between the discriminatory ability of the schemes . Conclusions Based on this single trial population , current risk stratification schemes in older people with atrial fibrillation have only limited ability to predict the risk of stroke . Given the systematic undertreatment of older people with anticoagulation , and the relative safety of warfarin versus aspirin in those aged over 70 , there could be a pragmatic rationale for classifying all patients over 75 as “ high risk ” until better tools are available Background : Atrial fibrillation ( AF ) is strongly associated with age , and epidemiologic studies are needed to evaluate the impact of both aging of the population and the use of anticoagulant therapy in patients with AF on the incidence of cardioembolic stroke with AF ( CE/AF stroke ) . Methods : We evaluated trends in incidence rates , risk factors , prestroke therapy , and survival in CE/AF stroke from a prospect i ve population -based registry , from 1985 to 2006 . Results : A total of 3,064 ischemic  strokes , including 572 ( 18.7 % ) CE/AF strokes , were recorded . Over the 22 years , a decrease in the incidence of overall CE/AF stroke was noted ( incidence rate ratio 0.9858 , 95 % confidence interval [ CI ] 0.9731–0.9986 ; p = 0.03 ) . We observed a higher prevalence of previous AF , previous myocardial infa rct ion , and patients aged > 70 years in CE/AF stroke ( p < 0.0001 ) whereas hypercholesterolemia was more prevalent in other ischemic strokes ( p = 0.003 ) . A significant increase in the use of anticoagulants and antiplatelet agents  was noted , and was particularly pronounced for CE/AF stroke with previous AF . For CE/AF stroke , survival rates were 72 % at 1 month ( 95 % CI 0.68–0.76 ) , 52 % at 1 year ( 95 % CI 0.48–0.56 ) , and 43 % at 2 years ( 95 % CI 0.39–0.48 ) , and remained lower than those of other ischemic stroke . Conclusions : The decrease in the incidence of cardioembolic/atrial fibrillation stroke in our study was probably due to a slight increase in the utilization of antithrombotic therapy in patients with atrial fibrillation , but the use of such therapies will have to increase further because of the expected aging of the population in coming years . AF = atrial fibrillation ; CE = cardioembolic ; CI = confidence interval ; IRR = incidence rate ratios BACKGROUND Atrial fibrillation ( AF ) is a major risk factor ( RF ) for ischemic stroke . Its prevalence and prognostic impact in patients with atherothrombosis are unclear . METHODS Risk factors , drug usage , and 1-year cardiovascular ( CV ) outcomes ( CV death , myocardial infa rct ion [ MI ] , and stroke ) were compared in  AF and non-AF patients from the REduction of Atherothrombosis for Continued Health ( REACH ) Registry , an international , prospect i ve cohort of 68,236 stable out patients with established atherothrombosis or > or=3 atherothrombotic RFs . RESULTS Atrial fibrillation and 1-year follow-up data are available for 63,589 patients . The prevalence of AF was , 12.5 % , 13.7 % , 11.5 % , and 6.2 % among coronary artery disease , CV disease , peripheral artery disease , and RF-only patients , respectively . Of the 6,814 patients with AF , 6.7 % experienced CV death , nonfatal MI , or nonfatal stroke within a year . The annual incidence of nonfatal stroke ( 2.4 % vs 1.6 % , P<.0001 ) and unstable angina ( 6.0 % vs 4.0 % , P<.00001 ) was higher , and CV death was more than double ( 3.2 % vs 1.4 % , P<.0001 ) , in AF versus non-AF patients . In these patients with or at high risk of atherothrombosis , most patients with AF received antiplatelet agents , but only 53.1 % were treated with oral anticoagulants . Even with high CHADS2 ( congestive heart failure , hypertension , aging , diabetes mellitus , and stroke ) scores , anticoagulant use did not exceed ( 59 % ) . The rate of bleeding requiring hospitalization was higher in AF versus non-AF patients ( 1.5 % vs 0.8 % , P<.0001 ) , possibly related to the more frequent use of anticoagulants ( 53.1 % vs 7.1 % ) . CONCLUSIONS Atrial fibrillation is common in patients with atherothrombosis , associated with more frequent fatal and nonfatal CV outcomes , and underuse of oral anticoagulants Background Only a few population -based cohort studies have investigated the impact of  atrial fibrillation ( AF ) on stroke in Japan . Methods A total of 10 929 participants ( 4147 men and 6782 women ) were included in this population -based prospect i ve cohort study . Baseline data , including  electrocardiograms ( ECGs )  to ascertain AF status , were obtained from April 1992 through July 1995 in 12 areas in Japan . Cox proportional hazards models were used to analyze the association of AF with stroke . Results A total of 54 participants had AF ( 0.49 % ) . The mean follow-up period was 10.7 years , during which 405 strokes were identified ; 12 of these occurred in participants with AF . The crude incidence of stroke in participants with and without AF was 14.9 and 4.5 per 1000 person-years in men , respectively , and 39.3 and 2.7 per 1000 person-years in women . After adjusting for geographical area , sex , age , smoking status , drinking status , obesity , hypertension , dyslipidemia , and diabetes mellitus , the hazard ratios ( 95 % confidence interval ) of AF in all participants and in male and female participants were 4.11 ( 2.28–7.41 ) , 2.12 ( 0.77–5.84 ) , and 10.6 ( 5.01–22.4 ) , respectively . The population attributable fraction ( PAF ) of stroke caused by AF was 2.2 % ; the PAFs were 1.0 % and 3.6 % in men and women , respectively . Conclusions The present Japanese population -based prospect i ve cohort study showed that AF is a major risk factor for stroke , especially in women Background Device‐detected sub clinical atrial fibrillation ( AF ) refers to infrequent , short‐lasting , asymptomatic AF that is detected only with long‐term continuous monitoring . Sub clinical AF is common and associated with an increased risk of stroke ; however , the risk of stroke with sub clinical AF is lower than for clinical AF , and very few patients with sub clinical AF alone have been included in large AF anticoagulation trials . The net benefit of anticoagulation in patients with sub clinical AF is unknown . Design ARTESiA is a prospect i ve , multicenter , double‐blind , r and omized controlled trial , recruiting patients with sub clinical AF detected by an implanted pacemaker , defibrillator , or cardiac monitor , and who have additional risk factors for stroke . Patients with clinical AF documented by surface electrocardiogram will be excluded from the study . Participants will be r and omized to receive either apixaban ( according to st and ard AF dosing ) or aspirin 81 mg daily . The primary outcome is the composite of stroke , transient ischemic attack with diffusion‐weighted magnetic resonance imaging evidence of cerebral infa rct ion , and systemic embolism . Approximately 4,000 patients will be enrolled from around 230 clinical sites , with an anticipated mean follow‐up of 36 months until 248 adjudicated primary outcome events have occurred . Summary ARTESiA will determine whether oral anticoagulation therapy with apixaban compared with aspirin reduces the risk of stroke or systemic embolism in patients with sub clinical AF and additional risk factors AIMS To test the hypothesis that stroke and systemic embolic events ( SEE ) in the stroke prevention using an oral thrombin inhibitor in atrial fibrillation ( SPORTIF ) III and V trials are different between paroxysmal and persistent atrial fibrillation ( AF ) . METHODS Data analysis from two cohorts of patients enrolled in the prospect i ve SPORTIF III and V clinical trials ( n = 7329 ) ; 836 subjects ( 11.4 % ) with paroxysmal AF [ mean age 70.1 years ( SD = 9.5 ) ] were compared with 6493 subjects with persistent AF for this ancillary study . RESULTS The annual event rates for stroke/SEE are 1.73 % for persistent AF and 0.93 % for paroxysmal AF . In a multivariate analysis , after adjusting for stroke risk factors , gender and aspirin usage , the differences remained statistically significant with a higher hazard ratio ( HR ) for stroke/SEE in persistent AF [ vs. paroxysmal AF , HR 1.87 , 95 % confidence interval ( CI ) 1.04 - 3.36 ; P = 0.037 ] . In ' high risk ' patients ( with > or=2 stroke risk factors ) annual event rates for stroke/SEE were 2.08 % for persistent AF and 1.27 % for paroxysmal AF ( adjusted HR = 1.68 , 95 % CI 0.91 - 3.1 , P = 0.098 ) . Elderly patients had annual event rates for stroke/SEE of 2.38 % for persistent AF and 1.13 % for paroxysmal AF ( adjusted HR = 2.27 , 95 % CI 0.92 - 5.59 , P = 0.075 ) . Vitamin K antagonist (VKA)-naive paroxysmal AF patients had a 1.89%/year stroke/SEE rate , compared with 0.61 % for previous VKA takers ( HR = 0.33 , 95 % CI 0.11 - 1.01 , P = 0.052 ) . CONCLUSION In this large clinical trial cohort of anticoagulated AF patients , those with paroxysmal AF had stroke rates which were lower than for patients with persistent AF , although both groups had broadly similar stroke risk factors . Subjects with paroxysmal AF at ' high risk ' had stroke/SEE rates that were not significantly different to persistent AF subjects OBJECTIVES To determine whether  atrial fibrillation ( AF )  is associated with risk of incident dementia or Alzheimer 's disease ( AD ) , beyond its effect on stroke . DESIGN Prospect i ve cohort study . SETTING An integrated healthcare delivery system . PARTICIPANTS A population -based sample of 3,045 community-dwelling adults aged 65 and older without dementia or clinical stroke followed from 1994 to 2008 . MEASUREMENTS AF was identified from health plan electronic data using International Classification of Diseases , Ninth Revision , codes from inpatient and outpatient encounters . Covariates came from self-report , study measures , and health plan data . Participants were screened every 2 years using the Cognitive Abilities Screening Instrument ( range 0 - 100 ) , with detailed neuropsychological and clinical assessment of those scoring less than 86 . A multidisciplinary consensus committee determined diagnoses of all-cause dementia and possible or probable AD using st and ard research criteria . RESULTS  AF  was present in 132 ( 4.3 % ) participants at baseline and was diagnosed in 370 ( 12.2 % ) more over a mean of 6.8 years of follow-up ; 572 participants ( 18.8 % ) developed dementia ( 449 with AD ) . The adjusted hazard ratio associated with AF was 1.38 ( 95 % confidence interval (CI)=1.10 - 1.73 ) for all-cause dementia and 1.50 ( 95 % CI=1.16 - 1.94 ) for possible or probable AD . Results were similar for participants with and without clinical ly recognized stroke during follow-up and in sensitivity analyses examining only probable AD . CONCLUSION AF is associated with higher risk of developing AD and dementia . Future studies should examine whether specific treatments , including optimal anticoagulation , can decrease this risk Background Oral anticoagulation prevents ischemic strokes in patients with atrial fibrillation ( AF ) . Early detection of AF and subsequent initiation of oral anticoagulation help to prevent strokes in AF patients . Implanted cardiac pacemakers and defibrillators allow seamless detection of atrial high rate episodes ( AHRE ) , but the best antithrombotic therapy in patients with AHRE is not known . Rationale Stroke risk is higher in pacemaker patients with AHRE than in those without , but the available data also show that stroke risk in patients with AHRE is lower than in patients with AF . Furthermore , only a minority of patients with AHRE will develop AF , many strokes occur without a temporal relation to AHRE , and AHRE can reflect other arrhythmias than AF or artifacts . An adequately powered controlled trial of oral anticoagulation in patients with AHRE is needed . Design The Non – vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes ( NOAH – AFNET 6 ) trial tests whether oral anticoagulation with edoxaban is superior to prevent the primary efficacy outcome of stroke or cardiovascular death compared with aspirin or no antithrombotic therapy based on evidence ‐based indications . The primary safety outcome will be major bleeding . NOAH – AFNET 6 will r and omize 3,400 patients with AHRE , but without documented AF , aged ≥65 years with at least 1 other stroke risk factor , to oral anticoagulation therapy ( edoxaban ) or no anticoagulation . All patients will be followed until the end of this investigator‐driven , prospect i ve , parallel‐group , r and omized , event‐driven , double‐blind , multicenter phase IIIb trial . Patients will be censored when they develop AF and offered open‐label anticoagulation . The sponsor is the Atrial Fibrillation NETwork ( AFNET ) . The trial is supported by the DZHK ( German Centre for Cardiovascular Research ) , the BMBF ( German Ministry of Education and Research ) , and Daiichi Sankyo Europe . Conclusion NOAH – AFNET 6 will provide robust information on the effect of oral anticoagulation in patients with atrial high rate episodes detected by implanted devices . Graphical abstract Figure . No Caption available
Few models had addressed the cumulative nature of risk factors where a combination of risk factors would confer a greater risk than either factor alone .
In patients at high risk of stroke , anticoagulation is cost effective , but not for those with a low risk of stroke .
The risk of stroke in atrial fibrillation ( AF ) needs to be assessed in each patient to determine the clinical and cost-effectiveness of thromboprophylaxis , with the aim of appropriate use of antithrombotic therapy .
To achieve this , stroke risk factors in AF population s need to be identified and stroke risk stratification models have been devised on the basis of these risk factors .
In this article , we firstly provide a systematic review of studies examining the attributable stroke risk of various clinical , demographic and echocardiographic patient characteristics in AF population s. Secondly , we performed a systematic review of published stroke risk stratification models , in terms of the results of the review of stroke risk factors and their ability to accurately discriminate between different levels of stroke risk .