Factors associated with ischemic stroke during aspirin therapy in atrial fibrillation: analysis of 2012 participants in the SPAF I-III clinical trials. The Stroke Prevention in Atrial Fibrillation (SPAF) Investigators. Assessment of three schemes for stratifying stroke risk in patients with nonvalvular atrial fibrillation. Patients with nonvalvular atrial fibrillation at low risk of stroke during treatment with aspirin: Stroke Prevention in Atrial Fibrillation III Study. The SPAF III Writing Committee for the Stroke Prevention in Atrial Fibrillation Investigators. Warfarin versus aspirin for prevention of thromboembolism in atrial fibrillation: Stroke Prevention in Atrial Fibrillation II Study Impact of a patient decision aid on care among patients with nonvalvular atrial fibrillation: a cluster randomized trial Anticoagulation therapy for stroke prevention in atrial fibrillation: how well do randomized trials translate into clinical practice? Effect of Age on Stroke Prevention Therapy in Patients With Atrial Fibrillation: The Atrial Fibrillation Investigators RISK OF STROKE IN NON-RHEUMATIC ATRIAL FIBRILLATION Adverse outcomes and predictors of underuse of antithrombotic therapy in medicare beneficiaries with chronic atrial fibrillation. Ximelagatran vs warfarin for stroke prevention in patients with nonvalvular atrial fibrillation: a randomized trial. Warfarin for atrial fibrillation. The patient's perspective. Predictors of thromboembolism in atrial fibrillation: II. Echocardiographic features of patients at risk. The Stroke Prevention in Atrial Fibrillation Investigators. Prognostic implications of left atrial spontaneous echo contrast in nonvalvular atrial fibrillation. Antithrombotic Treatment Patterns in Patients with Newly Diagnosed Nonvalvular Atrial Fibrillation: The GLORIA-AF Registry, Phase II. A randomized trial to assess the impact of an antithrombotic decision aid in patients with nonvalvular atrial fibrillation: the DAAFI trial protocol [ISRCTN14429643]
BACKGROUND AND PURPOSE Nonvalvular atrial fibrillation ( AF ) is a strong , independent risk factor for stroke , but the absolute rate of stroke varies widely among AF patients , importantly influencing the potential benefit of antithrombotic prophylaxis . We explore factors associated with ischemic stroke in AF patients taking aspirin .  METHODS We performed multivariate logistic regression analysis of 2012 participants given aspirin alone or in combination with low , inefficacious doses of warfarin in the Stroke Prevention in Atrial Fibrillation I-III trials followed for a mean of 2.0 years , during which 130 ischemic strokes were observed . RESULTS Age ( relative risk [RR]=1.8 per decade , P<0.001 ) , female sex ( RR=1.6 , P=0.01 ) , history of hypertension ( RR=2.0 , P<0.001 ) , systolic blood pressure > 160 mm Hg ( RR=2.3 , P<0.001 ) , and prior stroke or transient ischemic attack ( RR=2.9 , P<0.001 ) were independently associated with increased stroke risk . Regular consumption of > /=14 alcohol-containing drinks per week was associated with reduced stroke risk ( adjusted RR=0.4 , P=0.04 ) . Among SPAF III participants , estrogen hormone replacement therapy was associated with a higher risk of ischemic stroke ( adjusted RR=3.2 , P=0.007 ) . With the use of these variables , a risk stratification scheme for primary prevention separated participants into those with high ( 7.1%/y , 22 % of the cohort ) , moderate ( 2.6%/y , 37 % of the cohort ) , and low ( 0.9%/y , 41 % of the cohort ) rates of stroke . Ischemic strokes in low-risk participants were less often disabling ( P<0.001 ) . CONCLUSIONS Patients with AF who have high and low rates of stroke during treatment with  aspirin can be identified . However , validation of our risk stratification scheme is necessary before it can be applied with confidence to clinical management . Postmenopausal estrogen replacement therapy and moderate alcohol consumption may additionally modify the risk of stroke in AF , but these findings require confirmation 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 CONTEXT Nonvalvular atrial fibrillation ( AF ) carries an increased risk for stroke , but absolute rates of stroke vary widely within the broad spectrum of AF patients . OBJECTIVE To prospect ively vali date a risk stratification scheme identifying patients with AF with low rates of stroke when given aspirin .  DESIGN Prospect i ve cohort study with mean duration of follow-up of 2.0 years , conducted between 1993 and 1997 . SETTING Outpatient clinics affiliated with academic medical centers . PATIENTS Patients with AF categorized as " low risk " based on the absence of 4 prespecified thromboembolic risk factors : recent congestive heart failure or left ventricular fractional shortening of 25 % or less , previous thromboembolism , systolic blood pressure greater than 160 mm Hg , or female sex at age older than 75 years . INTERVENTION All participants given aspirin , 325 mg/d . MAIN OUTCOME MEASURES Ischemic stroke ( considered disabling when Rankin score was II or worse 1 - 3 months later ) and systemic embolism ( primary events ) . RESULTS Among 892 participants , the mean ( SD ) age was 67 ( 10 ) years , 78 % were men , and histories of hypertension , diabetes , and ischemic heart disease were present in 46 % , 13 % , and 16 % , respectively . The rate of primary events was 2.2 % per year ( 95 % confidence interval [ CI ] , 1.6%-3.0 % ) , of ischemic stroke was 2.0 % per year ( 95 % CI , 1.5%-2.8 % ) , and of disabling ischemic strokes was 0.8 % per year ( 95 % CI , 0.5%-1.3 % ) . Those with a history of hypertension had a higher rate of primary events ( 3.6 % per year ) than those with no history of hypertension ( 1.1 % per year ) ( P<.001 ) . The rate of disabling ischemic stroke was low in those with and without a history of hypertension ( 1.4 % per year and 0.5 % per year , respectively ) . The rate of major bleeding during aspirin therapy was 0.5 % per year . CONCLUSION Patients with AF who have relatively low rates of ischemic stroke , particularly disabling stroke , during treatment with aspirin can be reliably identified Warfarin is an established treatment for prevention of ischaemic stroke in patients with atrial fibrillation , but the value of this agent relative to aspirin in unclear . In the first Stroke Prevention in Atrial Fibrillation ( SPAF-I ) study , direct comparison of warfarin with aspirin was limited by the small number of thromboembolic events . SPAF-II aims to address this issue and also to assess the differential effects of the two treatments according to age . We compared warfarin ( prothrombin time ratio 1.3 - 1.8 , international normalised ratio 2.0 - 4.5 ) with aspirin 325 mg daily for prevention of ischaemic stroke and systemic embolism ( primary events ) in two parallel r and omised trials involving 715 patients aged 75 years or less and 385 patients older than 75 ; we sought reductions in the absolute rate of primary events by warfarin compared with aspirin of 2 % per year and 4 % per year , respectively . In the younger patients , warfarin decreased the absolute rate of primary events by 0.7 % per year ( 95 % CI-0.4 to 1.7 ) . The primary event rate per year was 1.3 % with warfarin and 1.9 % with aspirin ( relative risk [ RR ] 0.67 , p = 0.24 ) . The absolute rate of primary events in low-risk younger patients ( without hypertension , recent heart failure , or previous thromboembolism ) on aspirin was 0.5 % per year ( 95 % CI 0.1 to 1.9 ) . Among older patients , warfarin decreased the absolute rate of primary events by 1.2 % per year ( 95 % CI-1.7 to 4.1 ) . The primary event rate per year was 3.6 % with warfarin and 4.8 % with aspirin ( RR 0.73 , p = 0.39 ) . In this older group , the rate of all stroke with residual deficit ( ischaemic or haemorrhagic ) was 4.3 % per year with aspirin and 4.6 % per year with warfarin ( RR 1.1 ) . Warfarin may be more effective than aspirin for prevention of ischaemic stroke in patients with atrial fibrillation , but the absolute reduction in stroke rate by warfarin is small . Younger patients without risk factors had a low rate of stroke when treated with aspirin . In older patients the rate of stroke ( ischaemic and haemorrhagic ) was substantial , irrespective of which agent was given . Patient age and the inherent risk of thromboembolism should be considered in the choice of antithrombotic prophylaxis for patients with atrial fibrillation Background : Too few patients with nonvalvular atrial fibrillation ( NVAF ) receive appropriate antithrombotic therapy . We tested the short-term ( primary outcome ) and long-term ( secondary outcome ) effect of a patient decision aid on the appropriateness of antithrombotic therapy among patients with NVAF . Methods : We conducted a cluster r and omized trial with blinded outcome assessment involving 434 NVAF patients from 102 community-based primary care practice s. Patients in the intervention group received a self-administered booklet and audiotape decision aid tailored to their personal stroke risk profile . Patients in the control group received usual care . The primary outcome measure was change in antithrombotic therapy at 3 months . Appropriateness of therapy was defined using the American College of Chest Physicians ( ACCP ) recommendations . Results : The mean patient age was 72 years , and the median duration of NVAF was 5 years . In the control group , there was a 3 % decrease over 3 months in the number of patients receiving therapy appropriate to their risk of stroke ( 40 % [ 85/215 ] at baseline v. 37 % [ 79/215 ] at 3 months ) . In the intervention group , the number of patients receiving therapy appropriate to their stroke risk increased by 9 % ( 32 % [ 69/219 ] at baseline v. 41 % [ 89/219 ] at 3 months ) . Although the proportion of patients whose therapy met the ACCP treatment recommendations did not differ between study arms at baseline ( p = 0.11 ) or 3 months ( p = 0.44 ) , there was a 12 % absolute improvement in the number of patients receiving appropriate care in the intervention group compared with the control group at 3 months ( p = 0.03 ) . The beneficial effect of the decision aid did not persist ( p = 0.44 for differences between study arms after 12 months ) . Interpretation : There was short-term improvement in the appropriateness of antithrombotic care among patients with NVAF who were exposed to a decision aid , but the improvement did not persist CONTEXT Warfarin has been shown to be highly efficacious for preventing  thromboembolism in atrial fibrillation in r and omized trials , but its effectiveness and safety in clinical practice is less clear . OBJECTIVE To evaluate the effect of warfarin on risk of thromboembolism , hemorrhage , and death in atrial fibrillation within a usual care setting . DESIGN Cohort study assembled between July 1 , 1996 , and December 31 , 1997 , and followed up through August 31 , 1999 . SETTING Large integrated health care system in Northern California . PATIENTS Of 13,559 adults with nonvalvular atrial fibrillation , 11,526 were studied , 43 % of whom were women , mean age 71 years , with no known contraindications to anticoagulation at baseline . MAIN OUTCOMES Ischemic stroke , peripheral embolism , hemorrhage , and death according to warfarin use and comorbidity status , as determined by automated data bases , review of medical records , and state mortality files . RESULTS Among 11,526 patients , 397 incident thromboembolic events ( 372 ischemic strokes , 25 peripheral embolism ) occurred during 25,341 person-years of follow-up , and warfarin therapy was associated with a 51 % ( 95 % confidence interval [ CI ] , 39%-60 % ) lower risk of thromboembolism compared with no warfarin therapy ( either no antithrombotic therapy or aspirin ) after adjusting for potential confounders and likelihood of receiving warfarin . Warfarin was effective in reducing thromboembolic risk in the presence or absence of risk factors for stroke . A nested case-control analysis estimated a 64 % reduction in odds of thromboembolism with warfarin compared with no antithrombotic therapy . Warfarin was also associated with a reduced risk of all-cause mortality ( adjusted hazard ratio , 0.69 ; 95 % CI , 0.61 - 0.77 ) . Intracranial hemorrhage was uncommon , but the rate was moderately higher among those taking vs those not taking warfarin ( 0.46 vs 0.23 per 100 person-years , respectively ; P = .003 , adjusted hazard ratio , 1.97 ; 95 % CI , 1.24 - 3.13 ) . However , warfarin therapy was not associated with an increased adjusted risk of nonintracranial major hemorrhage . The effects of warfarin were similar when patients with contraindications at baseline were analyzed separately or combined with those without contraindications ( total cohort of 13,559 ) . CONCLUSIONS Warfarin is very effective for preventing ischemic stroke in patients with atrial fibrillation in clinical practice while the absolute increase in the risk of intracranial hemorrhage is small . Results of r and omized trials of anticoagulation translate well into clinical care for patients with atrial fibrillation Background and Purpose — Stroke risk increases with age in patients who have nonvalvular atrial fibrillation . It is uncertain whether the efficacy of stroke prevention therapies in atrial fibrillation changes as patients age . The objective of this study was to determine the effect of age on the relative efficacy of oral anticoagulants ( OAC ) and antiplatelet ( AP ) therapy ( including acetylsalicylic acid and triflusal ) on ischemic stroke , serious bleeding , and vascular events in patients with atrial fibrillation . Methods — This is an analysis of the Atrial Fibrillation Investigators data base , which contains patient level- data from r and omized trials of stroke prevention in atrial fibrillation . We used Cox regression models with age as a continuous variable that controlled for sex , year of r and omization , and history of cerebrovascular disease , diabetes , hypertension , and congestive heart failure . Outcomes included ischemic stroke , serious bleeding ( intracranial hemorrhage or systemic bleeding requiring hospitalization , transfusion , or surgery ) , and cardiovascular events ( ischemic stroke , myocardial infa rct ion , systemic embolism , or vascular death ) . Results — The analysis included 8932 patients and 17 685 years of observation from 12 trials . Patient age increased risk of ischemic stroke ( adjusted hazard ratio per decade increase 1.45 ; 95 % CI , 1.26 to 1.66 ) , serious bleeding ( 1.61 ; 1.47 to 1.77 ) , and cardiovascular events ( 1.43 ; 1.33 to 1.53 ) . Compared with placebo , OAC and AP significantly reduced the risk of ischemic stroke ( OAC , 0.36 ; 0.29 to 0.45 ; AP , 0.81 ; 0.72 to 0.90 ) and cardiovascular outcomes ( OAC , 0.59 ; 0.52 to 0.66 ; AP , 0.81 ; 0.75 to 0.88 ) , whereas OAC increased risk of serious bleeding ( 1.56 ; 1.03 to 2.37 ) . The relative benefit of OAC versus placebo or AP did not vary by patient age for any outcome . Compared with placebo , the relative benefit of AP  for preventing ischemic stroke decreased significantly as patients aged ( P=0.01 ) . Conclusions — As patients with atrial fibrillation age , the relative efficacy of AP to prevent ischemic stroke appears to decrease , whereas it does not change for OAC . Because stroke risk increases with age , the absolute benefit of OAC increases as patients get older Estimates of the risk of stroke for men with non-rheumatic atrial fibrillation were obtained from two large cohort studies --the Whitehall Study of London Civil Servants and the British  Regional Heart Study . The first cohort provided an estimated relative risk of stroke of 6.9 compared with controls . This increased risk confirms that of the other prospect i ve estimate , 5.6 , found in the Framingham study . In the second cohort only one of the men at risk had a stroke , and the risk estimate did not differ significantly from unity . The absolute rates of stroke in both cohorts were lower than those reported in the Framingham study , implying a lesser potential benefit from preventive measures . These lower rates should be considered in the planning of trials . The risk of stroke was significantly associated with raised systolic or diastolic blood pressure but not with age or coronary heart disease BACKGROUND AND PURPOSE Antithrombotic therapy can prevent strokes and transient ischemic attacks ( TIAs ) in carefully selected patients who have chronic nonvalvular atrial fibrillation ( NVAF ) . Our objectives were 3-fold : to document the use of warfarin and aspirin therapy in Missouri Medicare beneficiaries with chronic NVAF ; to identify factors associated with warfarin and aspirin underuse ; and to determine the association between prescription of warfarin and aspirin at hospital discharge and adverse outcomes in this elderly , frail population . METHODS We linked chart review s from all Missouri hospitals to Medicare cl aims data from 1993 to 1996 . From chart review s , we documented Medicare beneficiaries ' demographic factors , comorbid conditions , and antithrombotic therapy prescribed at the time of hospital discharge . From Medicare cl aims , we determined the date of outcomes -death from any cause or hospitalization for an ischemic event ( a stroke , a TIA , or a myocardial infa rct ion ) . RESULTS Only 328 ( 55 % ) of the 597 Medicare beneficiaries were prescribed antithrombotic therapy at hospital discharge : 34 % received warfarin and 21 % received aspirin . Advanced age , female gender , and rural residency predicted underuse of antithrombotic therapy . After controlling for these factors , as well as stroke risk factors and contraindications to anticoagulation , the prescription of warfarin was associated with a 24 % relative risk reduction ( RRR ) in adverse outcomes ( P=0.003 ) . Prescription of aspirin was associated with a nonsignificant 5 % RRR in these events ( P=0.56 ) . CONCLUSIONS The underuse of antithrombotic therapy in Medicare beneficiaries who have NVAF is associated with measurable adverse outcomes . The benefit of warfarin therapy may extend to frail , elderly patients , a group that was excluded from r and omized controlled trials . The role of antiplatelet therapy in this population deserves further study because many of these patients have relative contraindications to warfarin CONTEXT In patients with nonvalvular atrial fibrillation , warfarin prevents ischemic stroke , but dose adjustment , coagulation monitoring , and bleeding limit its use . OBJECTIVE To compare the efficacy of the oral direct thrombin inhibitor ximelagatran with warfarin for prevention of stroke and systemic embolism . DESIGN , SETTING , AND PARTICIPANTS Double-blind , r and omized , multicenter trial ( 2000 - 2001 ) conducted at 409 North American sites , involving 3922 patients with nonvalvular atrial fibrillation and additional stroke risk factors . INTERVENTIONS Adjusted-dose warfarin ( aim ing for an international normalized ratio [ INR ] 2.0 to 3.0 ) or fixed-dose oral ximelagatran , 36 mg twice daily . MAIN OUTCOME MEASURES The primary end point was all strokes ( ischemic or hemorrhagic ) and systemic embolic events . The primary analysis was based on demonstrating noninferiority within an absolute margin of 2.0 % per year according to the intention-to-treat model . RESULTS During 6405 patient-years ( mean 20 months ) of follow-up , 88 patients experienced primary events . The mean ( SD ) INR with warfarin ( 2.4 [ 0.8 ] ) was within target during 68 % of the treatment period . The primary event rate with ximelagatran was 1.6 % per year and with warfarin was 1.2 % per year ( absolute difference , 0.45 % per year ; 95 % confidence interval , -0.13 % to 1.03 % per year ; P<.001 for the predefined noninferiority hypothesis ) . When all-cause mortality was included in addition to stroke and systemic embolic events , the rate difference was 0.10 % per year ( 95 % confidence interval , -0.97 % to 1.2 % per year ; P = .86 ) . There was no difference between treatment groups in rates of major bleeding , but total bleeding ( major and minor ) was lower with ximelagatran ( 37 % vs 47 % per year ; 95 % confidence interval for the difference , -14 % to -6.0 % per year ; P<.001 ) . Serum alanine aminotransferase levels rose to greater than 3 times the upper limit of normal in 6.0 % of patients treated with ximelagatran , usually within 6 months and typically declined whether or not treatment continued ; however , one case of documented fatal liver disease and one other suggestive case occurred . CONCLUSIONS The results establish the efficacy of fixed-dose oral ximelagatran without coagulation monitoring compared with well-controlled warfarin for prevention of thromboembolism in patients with atrial fibrillation requiring chronic anticoagulant therapy , but the potential for hepatotoxicity requires further investigation OBJECTIVE To determine the minimal clinical ly important difference ( MCID ) of warfarin therapy for the treatment of nonvalvular atrial fibrillation from the perspective of patients using 2 different elicitation methods . DESIGN All patients completed 2 face-to-face interviews , which were 2 weeks apart . For each interview , they were r and omized to receive 1 of 2 elicitation methods : ping-ponging or starting at the known efficacy . SETTING The practice s of 2 university-affiliated family medicine centers ( 8 physicians each ) , 14 community-based family physicians , and 2 cardiologists . PATIENTS Sixty-four patients with nonvalvular atrial fibrillation who were initiated with warfarin therapy at least 3 months before the study . INTERVENTION During each interview , the patients ' MCIDs were determined by using ( 1 ) a pictorial flip chart to describe atrial fibrillation ; the consequences of a minor stroke , a major stroke , and a major bleeding episode ; the chance of stroke if not taking warfarin ; the chance of a major bleeding episode if taking warfarin ; examples of the inconvenience , minor side effects , and costs of warfarin therapy ; and then ( 2 ) 1 of the 2 elicitation methods to determine their MCIDs ( the smallest reduction in stroke risk at which the patients were willing to take warfarin ) . Patients ' knowledge of their stroke risk , acceptability of the interview process , and factors determining their preferences were also assessed . MAIN RESULTS Given a baseline risk of having a stroke in the next 2 years , if not taking warfarin , of 10 of 100 , the mean MCID was 2.01 of 100 ( 95 % confidence interval , 1.60 - 2.42 ) . Fifty-two percent of the patients would take warfarin for an absolute decrease in stroke risk of 1 % over 2 years . Before eliciting their MCIDs , patients showed poor knowledge of their stroke risk , which improved afterward . The interview process was well accepted by the patients . The MCID using the ping-ponging elicitation method was 1.015 of 100 smaller compared with use of the starting at the known efficacy method ( P = .01 ) . CONCLUSIONS We were able to determine the MCID of warfarin therapy for the prevention of stroke from the perspective of patients with nonvalvular atrial fibrillation . Their MCIDs were much smaller than those that have been implied by some experts and clinicians . The interview process , using the flip chart approach , appeared to improve the patients ' knowledge of their disease and its consequences and treatment . The method used to elicit the patients ' MCIDs can have a clinical ly important effect on patient responses . The method used in our study can be generalized to other conditions and , thus , could be helpful in 3 ways : ( 1 ) from a clinical decision-making perspective , it could facilitate patient-physician communication ; ( 2 ) it could clarify the patient perspective when interpreting the results of previously completed trials ; and ( 3 ) it could be used to derive more clinical ly relevant sample sizes for r and omized treatment trials OBJECTIVE To identify echocardiographic predictors of arterial thromboembolism in patients with nonrheumatic atrial fibrillation and to determine whether these add to clinical variables for risk stratification . DESIGN Cohort study of patients assigned to placebo in a r and omized clinical trial . SETTING Five hundred sixty-eight in patients and out patients with nonrheumatic atrial fibrillation assigned to placebo therapy at 15 U.S. medical centers from 1987 to 1989 in the Stroke Prevention in Atrial Fibrillation study . Patients were followed for a mean of 1.3 years . MEASUREMENTS M-mode and two-dimensional ( 2-D ) echocardiograms performed at study entry and interpreted by local cardiologists . The predictive value of 14 echocardiographic variables for later ischemic stroke or systemic embolism was assessed by multivariate analysis . MAIN RESULTS Left ventricular dysfunction from 2-D echocardiograms ( P = 0.003 ) and the size of the left atrium from M-mode echocardiograms ( P = 0.02 ) were the strongest independent predictors of later thromboembolism . Multivariate analysis of these two independent echocardiographic predictors with the three independent clinical predictors of thromboembolism ( history of hypertension , recent congestive heart failure , previous thromboembolism ) identified 26 % of the cohort with a low risk for thromboembolism ( 1.0 % per year ; 95 % Cl , 0.2 % to 4.0 % ) . Compared with risk stratification using clinical variables alone , echocardiographic results altered thromboembolic risk stratification in 18 % of the entire cohort and in 38 % of those without clinical risk factors . CONCLUSIONS Both left ventricular and left atrial variables are significant predictors of thromboembolism in patients with nonvalvular atrial fibrillation . Our results challenge traditional views of the pathogenesis of ischemic stroke in patients with atrial fibrillation and suggest that st and ard echocardiography contributes to risk stratification , differentiating the one third of patients without clinical risk factors who are at increased risk for stroke from the remainder who may not need antithrombotic prophylaxis OBJECTIVES This study examined the influence of left atrial spontaneous echo contrast on the subsequent stroke or embolic event rate and on survival in patients with nonvalvular atrial fibrillation . BACKGROUND Left atrial spontaneous echo contrast is associated with atrial fibrillation and a history of previous stroke or other embolic events . However , the prognostic implication s of spontaneous contrast in patients with nonvalvular atrial fibrillation are unknown . METHOD The study group comprised 272 consecutive patients with nonvalvular atrial fibrillation undergoing transesophageal echocardiography .  Clinical and echocardiographic data were collected at baseline , and patients were prospect ively followed up , and all strokes , other embolic events and deaths were documented . The relation between spontaneous contrast at baseline and subsequent stroke , other embolic events and survival was analyzed . RESULTS Left atrial spontaneous echo contrast was detected at baseline in 161 patients ( 59 % ) . The mean follow-up was 17.5 months . The stroke or other embolic event rate was 12%/year ( 15 strokes , 3 transient ischemic attacks , 2 peripheral embolisms ) in patients with , compared with 3%/year ( 5 strokes ) in patients without , baseline spontaneous contrast ( p = 0.002 ) . In 149 patients without previous thromboembolism , the event rate was 9.5%/year in patients with and 2.2%/year in patients without spontaneous contrast ( p = 0.003 ) . There were 25 deaths in patients with and 11 deaths in patients without spontaneous contrast . Patients with spontaneous contrast had significantly reduced survival ( p = 0.025 ) . On multivariate analysis , spontaneous contrast was the only positive predictor ( odds ratio 3.5 , p = 0.03 ) and warfarin therapy on follow-up the only negative predictor ( odds ratio 0.23 , p = 0.02 ) of subsequent stroke or other embolic events . CONCLUSIONS Transesophageal echocardiography can risk stratify patients with nonvalvular atrial fibrillation by identifying left atrial spontaneous echo contrast . These patients have both a significantly higher risk of developing stroke or other embolic events and a reduced survival , and they may represent a subgroup in whom the risk/benefit ratio of anticoagulation may be most favorable BACKGROUND The Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation ( GLORIA-AF ) was design ed to provide prospect ively collected information on patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke , with the aim of addressing treatment patterns and questions of effectiveness and safety . METHODS AND RESULTS In this predefined analysis from GLORIA-AF , the baseline characteristics and initial antithrombotic management of the first 10,000 patients in Phase II of this large Registry Program are presented . Overall , 32.3 % of patients received vitamin K antagonists ( VKAs ) and 47.7 % received non-VKA oral anticoagulants ( NOACs ) , while 12.3 % received antiplatelet treatment and 7.6 % did not receive any antithrombotic treatment . Among patients with CHA2DS2-VASc score ≥2 , 6.7 % received no antithrombotic treatment and 10.0 % received aspirin . In Europe , treatment with dabigatran was as common as treatment with VKAs ( 38.8 % and 37.8 % , respectively ) . More than half of the patients were treated with NOACs ( 52.4 % ) , while antiplatelet treatment was given to 5.7 % , and 4.1 % did not receive any antithrombotic treatment . In North America , treatment with dabigatran  ( 25.0 % ) was as common as with VKAs ( 26.1 % ) , but overall NOAC use was more common ( 52.1 % ) than with VKAs ( 26.1 % ) ; however , 14.1 % received antiplatelet treatment , while 7.6 % received no antithrombotic treatment . In Asia , treatment with VKAs ( 31.9 % ) was more prevalent than NOACs ( 25.5 % ) , but antiplatelet treatment was given to 25.8 % , and 16.9 % did not receive any antithrombotic treatment . In Asia , only 60.7 % of patients with high stroke risk received oral anticoagulants ( OACs ) . Paroxysmal atrial fibrillation and minimally symptomatic ( or asymptomatic ) patients were often undertreated with OACs . CONCLUSION In this analysis , OAC use was high in Europe and North America , with overall NOAC use higher than VKA use . A considerable percentage of high-risk patients in North America still received antiplatelet treatment or were untreated , while Asian patients had a high proportion of aspirin use and nontreatment Background Decision aids are often advocated as a means to assist patient and health care provider decision making when faced with complicated treatment or screening decisions . Despite an exponential growth in the availability of decision aids in recent years , their impact on long-term treatment decisions and patient adherence is uncertain due to a paucity of rigorous studies . The choice of antithrombotic therapy for nonvalvular atrial fibrillation ( NVAF ) is one condition for which a trade-off exists between the potential risks and benefits of competing therapies , and the need to involve patients in decision making has been clearly identified . This study will evaluate whether an evidence -based patient decision aid for patients with NVAF can improve the appropriateness of antithrombotic therapy use by patients and their family physicians . Design A multi-center , two-armed cluster r and omized trial based in community family practice s in which patients with NVAF will be r and omized to decision aid or usual care . Patients will receive one of four decision aids depending on their baseline stroke risk . The primary outcome is the provision of " appropriate antithrombotic therapy " at 3 months to study participants ( appropriateness defined as per the 2001 American College of Chest Physicians recommendations for NVAF ) . In addition , the impact of this decision aid on patient knowledge , decisional conflict , well-being , and adherence will be assessed after 3 months , 6 months , and 12 months
Female sex was inconsistently associated with stroke risk , whereas the evidence was inconclusive that either heart failure or coronary artery disease is independently predictive of stroke .
Conclusions : Four clinical features ( prior stroke/TIA , advancing age , hypertension , diabetes ) are consistent independent risk factors for stroke in atrial fibrillation patients .
Background : Absolute stroke rates vary widely among patients with nonvalvular atrial fibrillation .
To balance the benefits and risks of chronic antithrombotic prophylaxis , it is important to estimate the absolute risk of stroke for individual patients .