Search

Numerous vascular risk factors and vascular diseases contribute to cognitive impairment and dementia. Many studies and registries show an association of atrial fibrillation (AF) with cognitive impairment, cognitive decline, and dementia. This is true for vascular dementia and Alzheimer's disease. The assumed multifactorial mechanisms include ischemic stroke, both apparent and silent, cerebral microinfarcts, cerebral hemorrhage, and reduced cerebral blood flow. A number of retrospective observational and prospective studies support that anticoagulation in patients with AF may reduce the risk of cognitive decline and dementia. This holds for both vitamin K antagonists (e.g., warfarin) and direct oral anticoagulants. However, it still remains unproven if anticoagulation reduces cognitive decline and dementia in AF patients based on randomized trials. [ABSTRACT FROM AUTHOR]

Background Whether patients with atrial fibrillation (AF) and liver disease are also prone to cerebrovascular events and respond similarly favorably to antithrombotic therapy remains under-investigated. Methods Patients ≥ 18 years with newly-diagnosed AF in the period 2005 to 2009 were scrutinized from the “Longitudinal Health Insurance Database 2005” (1 million beneficiaries) of Taiwan's National Health Insurance Institute. Patients were categorized into the Liver ( N = 433) or the Non-liver ( N = 3490) cohort according to whether they had a diagnosis of advanced liver disease. Patients were then followed to determine cumulative incidence of hospitalization-requiring cerebrovascular events, preventive effects of antithrombotics, and predictors of cerebrovascular events by Cox regression analysis. Results Within a mean follow-up of 3.3 ± 1.4 years, ischemic stroke (89.2 vs. 50.3 per 1000 person-years, adjusted HR 1.502, 95% CI 1.207–1.868, p < 0.001) and overall cerebrovascular events (102.3 vs. 56.4 per 1000 person-years, adjusted HR 1.535, 95% CI 1.251–1.883, p < 0.001) occurred significantly more often in the Liver than in the Non-liver cohort. Cox models identified aging (≥ 65 years), DM, and CHA2DS-VASc score ≥ 2 points as risk factors for overall cerebrovascular events in the Liver cohort, whereas antiplatelet agents (HR 0.932, 95% CI 0.128–6.803, p = NS) and vit-K antagonistic anticoagulants (HR 1.087, 95% CI 0.150–7.862, p = NS) showed no correlation. Conclusion AF patients comorbid with advanced liver disease are more vulnerable to ischemic and therein overall cerebrovascular events, especially in those with old age, DM, or high CHA2DS-VASc scores. This propensity to cerebrovascular events, however, can't be altered by antithrombotic therapy. [ABSTRACT FROM AUTHOR]

Abstract: Background: The CHADS2 score is a stroke risk stratification system for patients with atrial fibrillation (AF). The relationship between the pre-admission CHADS2 score and stroke severity or outcome was examined in AF-related cardioembolic stroke patients. Methods: 423 consecutive AF-related cardioembolic stroke patients (250 men, 173 women; aged 76±10years) were reviewed. Results: Pre-admission CHADS2 scores of 0, 1, 2, 3, 4, 5, and 6 were present in 4.3%, 21.0%, 34.3%, 23.6%, 11.8%, 4.5%, and 0.5% of patients, respectively. There were significant correlations (P<0.001) between CHADS2 and National Institutes of Health Stroke Scale (NIHSS) scores on admission, and CHADS2 and modified Rankin scale (mRS) scores at discharge. The optimal cutoff CHADS2 score for an mRS score ≥3 was ≥2 (sensitivity 84%, specificity 38%). For death, the optimal cutoff CHADS2 score was ≥3 (sensitivity 59%, specificity 62%). On multivariate analysis, a CHADS2 score ≥2 was independently associated with an mRS score ≥3 (OR 1.93, 95% CI 1.39–2.72, P<0.001), and a CHADS2 score ≥3 was independently associated with death (OR 1.46, 95% CI 1.02–2.11, P=0.038). Conclusions: The CHADS2 score is related to severity and outcomes of stroke in patients with AF. [Copyright &y& Elsevier]

Abstract: Background: : Atrial fibrillation (AF) is a risk factor for ischemic stroke. Stroke-prevention strategies based on risk schemes have been developed but most of the data are from western people. Our goal is to investigate the risk factors of ischemic stroke in Taiwanese with AF in a nation-wide database. Methods: : A universal national health insurance (NHI) program has been implemented in Taiwan since 1995. We used system sampling database from 1997 to 2008 with a total of 1,000,000 subjects. By using ambulatory and inpatient claim data, we included subjects with AF and were above 20 years old. We excluded those who had ever taken warfarin or aspirin or had valvular heart diseases. Result: : A total of 7920 patients (3633 women, 4287 men) were included in the final analyses. Cox regression analysis showed that the risk factors for ischemic stroke were age (OR=1.338 for age 65–74 years vs. age 20–64 years, P =0.014; OR=1.652 for age over 75 years vs. age 20–64years, P <0.001), hypertension (HTN) (OR=2.656, P <0.001), diabetes mellitus (DM) (OR=1.341, P =0.005), heart failure (OR=1.611, P <0.001), previous ischemic stroke or transient ischemic accident (TIA) (OR=2.752, P <0.001) and peripheral arterial disease (PAD) (OR=1.814, P =0.006). The gender, coronary artery disease, history of myocardial infarction and chronic renal insufficiency were not associated with ischemic stroke. The rate of ischemic stroke was much lower in current cohort as compared with that in whites. Frequent used risk schemes including CHADS2 and CHA2DS2-VASC had comparable but only limited ability to predict ischemic stroke in subjects with AF. Conclusion: : Compare with western people, hypertension plays a more important role in ischemic stroke in Taiwanese with AF and the incidence is lower. A substantial number of ischemic strokes cannot be accurately predicted by current risk schemes. [Copyright &y& Elsevier]

Objectives: This study tried to determine the association between left atrial (LA) fibrosis, detected using delayed-enhanced magnetic resonance imaging (DE-MRI), and the CHADS2 score (point system based on individual clinical risk factors including congestive heart failure, hypertension, age, diabetes, and prior stroke) variables, specifically stroke. Background: In patients with atrial fibrillation (AF), conventional markers for the risk of stroke base their higher predictive effect on clinical features, particularly previous stroke history, and not individual LA pathophysiological properties. We aimed to determine the association between LA fibrosis, detected using DE-MRI, and the CHADS2 score variables, specifically stroke. Methods: Patients with AF who presented to the AF clinic and received a DE-MRI of the LA were evaluated. Their risk factor profiles, including a CHADS2 score, were catalogued. The degree of LA fibrosis was determined as a percentage of the LA area. Any history of previous strokes, warfarin use, or cerebrovascular disease was recorded. Results: A total of 387 patients, having a mean age of 65 ± 12 years, 36.8% female, were included in this study. A history of previous stroke was present in 36 (9.3%) patients. Those patients with previous strokes had a significantly higher percentage of LA fibrosis (24.4 ± 12.4% vs. 16.2 ± 9.9%, p < 0.01). A larger amount of LA fibrosis was also seen in those patients with a higher CHADS2 score (≥2: 18.7 ± 11.4 vs. <2: 14.7 ± 9.2, p < 0.01). A logistic regression analysis of all variables except strokes (CHAD score) demonstrated that LA fibrosis independently predicted cerebrovascular events (p = 0.002) and significantly increased the predictive performance of the score (area under the curve = 0.77). Conclusions: Our preliminary, multicenter results suggest DE-MRI–based detection of LA fibrosis is independently associated with prior history of strokes. We propose that the amount of DE-MRI–determined LA fibrosis could represent a marker for stroke and a possible therapeutic target with potential applicability for clinical treatment for patients with AF. [Copyright &y& Elsevier]

The prevalence of atrial fibrillation (AF) is related to age and is projected to rise exponentially as the population ages and the prevalence of cardiovascular risk factors increases. The risk of ischemic stroke is significantly increased in AF patients, and there is evidence of a graded increased risk of stroke associated with advancing age. Oral anticoagulation (OAC) is far more effective than antiplatelet agents at reducing stroke risk in patients with AF. Therefore, increasing numbers of elderly patients are candidates for, and could benefit from, the use of anticoagulants. However, elderly people with AF are less likely to receive OAC therapy. This is mainly due to concerns about a higher risk of OAC-associated hemorrhage in the elderly population. Until recently, older patients were under-represented in randomized controlled trials of OAC versus placebo or antiplatelet therapy, and therefore the evidence base for the value of OAC in the elderly population was not known. However, analyses of the available trial data indicate that the expected net clinical benefit of warfarin therapy is highest among patients with the highest untreated risk for stroke, which includes the oldest age category. An important caveat with warfarin treatment is maintenance of a therapeutic international normalized ratio, regardless of the age of the patient, where time in therapeutic range should be ≥65%. Therefore, age alone should not prevent prescription of OAC in elderly patients, given an appropriate stroke and bleeding risk stratification. [ABSTRACT FROM AUTHOR]

Abstract: Background: We investigated atrial fibrillation (AF) prevalence, incidence and the risk of stroke and all-cause death because little is known about AF risk among ethnic Chinese. Methods: We conducted a community-based prospective cohort study among 3560 participants. Prevalent and incident AF was documented by using the 12-lead ECG in baseline and serial follow-ups, and the stroke and all-cause death events were ascertained. Results: Overall prevalence rates of AF in the cohort were 1.4% in men and 0.7% in women. Incidence rates of AF were 1.68 per 1000 person-years for men and 0.76 per 1000 person-years for women. During a median 13.8 years'' follow-up, we documented 208 cases of stroke and 776 deaths. As compared with those without AF, participants with AF had nearly 4 times the age, gender-adjusted risk of stroke (relative risk [RR], 3.87, 95% confidence interval [CI], 2.12–7.15), and twice the risk of death associated with all causes (RR, 2.23, 95% CI, 1.52–3.27). Further adjustment for body mass index, lifestyle factors, socioeconomic status and clinical diseases slightly attenuated these risks. In addition, after adjusting for echocardiographic measures, the following risks remained significant: the multivariate RRs were 2.90 (95% CI, 1.28–6.59) for risk of stroke and 2.05 (95% CI, 1.27–3.32) for risk of all-cause death among participants with AF. Conclusion: Our data demonstrate that AF is a significant risk factor for stroke and all-cause death for the Chinese. [Copyright &y& Elsevier]

Thromboembolism is a severe complication in atrial fibrillation. This overview presents thromboembolic disease as a single entity, ranging from stroke through mesenteric ischemia to acute limb ischemia. The PubMed, Embase, and Cochrane databases were systematically searched for the terms “atrial fibrillation” and “thromboembolism” in reports published from January 1986 to September 2009. The information of 10 evidence-based practice guideline documents and 61 further sources was systematically extracted. In atrial fibrillation, the average annual stroke risk is increased by 2.3% (lethality 30%). The annual incidence of acute mesenteric ischemia is 0.14% (lethality 70%), and that of acute limb ischemia is 0.4% (lethality 16%). In total, approximately 80% of embolism-related deaths are from stroke and 20% from other systemic thromboembolism. The ischemic symptoms generally have an acute onset but may mimic other diseases, particularly in mesenteric ischemia. Early diagnosis and treatment can limit or even prevent tissue infarction. Guideline-recommended therapy with aspirin or warfarin reduces the thromboembolic risk. Suitable patients may optimize their warfarin therapy by self-monitoring of the international normalized ratio (INR). New oral and parenteral anticoagulants with more stable pharmacokinetics are being developed. In conclusion, atrial fibrillation predisposes to thromboembolism. If ischemic stroke or systemic thromboembolism occurs, early diagnosis and treatment can improve outcomes. The thromboembolic risks are reduced by guideline-adherent antithrombotic therapy with warfarin or aspirin. Future directions may include self-monitoring of the international normalized ratio and novel anticoagulants. [Copyright &y& Elsevier]

Atrial fibrillation (AF) is a common complication of acute myocardial infarction (AMI) and this arrhythmia is associated with increased morbidity and mortality in patients with AMI. Limited information is available, however, about changing, and contemporary, trends in the incidence and death rates associated with AF complicating AMI. We examined the magnitude and impact of AF and the risk of stroke and hospital and long-term death rates in a population-based study of patients hospitalized with AMI. The study population consisted of 7,513 residents of the Worcester, Massachusetts, metropolitan area hospitalized with AMI at all greater Worcester medical centers during 9 biennial years from 1990 to 2005. Overall incidence of AF complicating AMI was 13.3% and rates of AF increased during the most recent years under study. Patients who developed AF were at greater risk for acute stroke (adjusted odds ratio 2.25, 95% confidence interval 1.36 to 3.71) and dying during hospitalization (adjusted odds ratio 1.79, 95% confidence interval 1.46 to 2.19) compared with patients who did not develop AF during hospitalization for AMI. Postdischarge survival was significantly poorer in patients who developed AF. Odds of dying after AF did not change appreciably over the years under study. In conclusion, results of this study in residents of a large New England metropolitan area suggest that AF remains a frequent complication of AMI and is associated with a poor prognosis. Increased surveillance and targeted therapeutic approaches appear warranted for these high-risk patients. [Copyright &y& Elsevier]

Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in clinical practice. The abnormal rhythm is associated not only with a variety of symptoms, such as palpitations, dizziness, or shortness of breath, but also with increased risk of stroke, heart failure, and mortality. A genetic predisposition is suggested by the fact that the relative risk for the development of AF is estimated at 85% in individuals with at least one parent with a history of AF. Current therapeutic strategies include control of rate or rhythm with medication and catheter ablation procedures. Especially in the pathophysiology of paroxysmal AF, ectopic electrical activity originating in the myocardial sleeves surrounding the pulmonary veins is considered causal. In these cases, ablation is applied to isolate the pulmonary venous myocardium from the remainder of the left atrial myocardium. Other recent evidence has shown that genetic and developmental defects can be involved in the development of AF. In this review, it is our aim to discuss the possible underlying causes of AF from a combined genetic and cardiac developmental view. [Copyright &y& Elsevier]

Abstract: Introduction: We aimed to determine the level of INR control associated with reduced stroke and mortality. Material and methods: The study used a retrospective cohort design using linked inpatient, haematology and mortality data from Cardiff and the Vale of Glamorgan, UK. Anonymised patients admitted with a diagnosis of non-valvular atrial fibrillation (NVAF) were defined as warfarin or non-warfarin treated by number of repeated International Normalised Ratio (INR) tests. Warfarin treated patients (>5 INR tests) categorised as at moderate or high risk of stroke (CHADS2 score ≥2) with varying levels of INR control were compared to those who did not receive warfarin treatment using Cox proportional hazards models controlling for age, sex and CHADS2 score. Outcome measures were time to stroke and mortality. Results: 6,108 patients with NVAF were identified. 2,235 (36.6%) of these patients had five or more INR readings and of these 486 (21.7%) had CHADS2 score ≥2. There was significant improvement in time to stroke event in those patients with INR control of greater than 70% of time in therapeutic range (2.0 to 3.0) compared with the non-warfarin treatment group. Overall survival was significantly improved for all warfarin treated groups with INR control of greater than 40% of time in range. Conclusions: Patients with INR control of above 70% of time in range had a significantly reduced risk of stroke. Patient suitability for warfarin treatment should be continuously assessed based on their ability to maintain a consistently therapeutic INR. [Copyright &y& Elsevier]

Abstract: Objectives: This study examined compliance with prescribing guidelines for antithrombotic therapy in patients with atrial fibrillation (AF) in Taiwan, using the 2001 joint guideline from the American College of Cardiology, American Heart Association, and European Society of Cardiology. The study also sought to identify factors associated with the appropriate prescribing of antithrombotic therapy. Methods: Patients with AF were identified by the presence of ≥2 inpatient or outpatient claims with an International Classification of Diseases, Ninth Revision, Clinical Modification code of 427.31 in the Taiwanese National Health Insurance claims database between July 1, 2003, and June 30, 2004. Patients were stratified according to their stroke risk (highest, high, low, or lowest) and antithrombotic medication (aspirin, warfarin, ticlopidine/clopidogrel, or none). Based on these categories, rates of prescribed treatments that were compliant with the antithrombotic guidelines were calculated. Antithrombotic therapies were considered guideline compliant when warfarin was prescribed for the highest- or high-risk patients, aspirin was prescribed for low-risk patients, and aspirin or no antithrombotic treatment was prescribed for the lowest-risk patients. Because the role of ticlopidine/clopidogrel in AF remains unclear, prescription of these drugs without aspirin or warfarin was considered noncompliant with the guidelines. Results: Of 39,541 identified patients with AF, 70.3% were at high risk for thromboembolic events and 18.3% were at highest risk; however, only 24.7% of the overall population received appropriate antithrombotic therapy. When patients with risk factors for bleeding were excluded, the rate of compliance increased to 26.2%. Factors that were inversely associated with prescription of warfarin included risk factors for bleeding (cancer, predisposition to falls, previous hemorrhage, history of peptic ulcer, cirrhosis, renal dialysis, and psychiatric disease), hypertension, coronary artery disease, thyrotoxicosis, and age ≥60 years. Conclusions: Most of these patients with AF in Taiwan did not receive appropriate antithrombotic therapy over the period studied. Bleeding risk factors, hypertension, coronary artery disease, thyrotoxicosis, and older age were associated with low rates of warfarin use. [Copyright &y& Elsevier]

Abstract: Background: Although several risk factors for stroke have been reported in patients with atrial fibrillation (AF), the relation of LV diastolic dysfunction to stroke is still uncertain in these patients. We evaluated the relationship between tissue Doppler-derived index, E/E'', as well as other clinical and echocardiographic parameters and ischemic stroke by this cross-sectional study. Methods: Three hundred thirty patients with persistent AF who had preserved LV ejection fraction were included from 6 centers. Clinical data were obtained and standard transthoracic echocardiography was performed. Patients without a history of ischemic stroke (n =280) were compared with patients with this complication (n =50). Potential determinants of ischemic stroke were identified by logistic regression analyses. Results: In univariate analyses, age, history of hypertension, diabetes mellitus, hyperlipidemia and symptomatic heart failure, plasma brain natriuretic peptide (BNP) level, early mitral inflow velocity (E), diastolic mitral annular velocity (E''), and E/E'' ratio were significantly correlated to ischemic stroke. Multivariate regression analyses identified two significant variables that were independently associated with ischemic stroke: hypertension (odds ratio=6.03, p =0.008), and E/E'' (odds ratio=1.21, p =0.002). Conclusions: These findings may have clinical implications that LV diastolic dysfunction, reflected by E/E'', is a significant determinant of ischemic stroke in AF. A larger prospective data is needed to confirm the value of E/E'' in risk stratification for ischemic stroke in this population. [Copyright &y& Elsevier]

Warfarin is underused for stroke prevention in atrial fibrillation (AF). Previous studies addressing this have lacked longitudinal assessment. This study sought to characterize contemporary warfarin use in new-onset AF and evaluate its change over time. It was hypothesized that AF recurrence has an important influence on warfarin use patterns. One thousand five adults from 17 centers in the United States and Canada were enrolled into a prospective observational registry after their first documented episodes of AF. Detailed demographic, clinical history, and management data were collected on all subjects at enrollment, including medication use. Patients were followed at regular intervals for interim events and changes in AF management. Warfarin use at baseline and last follow-up (mean 25 ± 8 months) after enrollment was modeled using multivariate analysis. Initially, 65% of subjects were prescribed warfarin, but only 44% were taking it at 30 months. Even in “ideal” candidates for warfarin, the rate of warfarin prescription decreased from 70% at baseline to 50% at 30 months. Stroke risk factors, including hypertension, congestive heart failure, valvular heart disease, and previous stroke or transient ischemic attack were significant predictors of warfarin prescription at baseline. At last follow-up, the relation between AF recurrence and warfarin use (odds ratio 2.3, 95% confidence interval 1.6 to 3.1) was stronger than that for any individual stroke risk factor. In conclusion, predictors of warfarin use in patients with AF include AF recurrence and selected stroke risk factors. The discontinuation of warfarin in a large number of patients with AF over time is a cause for concern in light of data from recent clinical trials. [Copyright &y& Elsevier]

Using a Medicare-based retrospective cohort study, the stroke risk in patients with atrial flutter (RR = 1.41) was determined to be greater than that in a control group (RR = 1.00) but less than that in an atrial fibrillation group (RR = 1.64). Furthermore, patients with atrial flutter who subsequently had an episode of atrial fibrillation had a higher risk of stroke (RR = 1.56) than patients with atrial flutter who never had a subsequent episode of atrial fibrillation (RR = 1.11). [ABSTRACT FROM AUTHOR]

Examines various aspects of atrial fibrillation as a risk factor for stroke. Cardiac causes; Natural history; Association of thrombolytic agents and atrial fibrillation; Prognostic implications; Effectiveness of anticoagulant warfarin; Effectiveness of aspirin in stroke prevention.

Abstract: Background: Congestive heart failure in sinus rhythm ranks second after atrial fibrillation (AF) among cardiogenic risk-factors for stroke. Clinical and echocardiographic predictors of stroke in this high-risk population remain poorly defined. Methods: Retrospective screening of 1886 consecutive patients with severe systolic dysfunction (LVEF ≤35%) at a tertiary medical center echocardiography database (Nov 2005–Sep 2008) identified 83 patients in sinus rhythm with cardioembolic stroke. Patients with AF on follow-up, prosthetic valve, ventricular arrhythmia and lack of consensus between reviewing neurologists were excluded (n =10). Consecutive age and gender-matched controls in sinus rhythm formed GpII (n =73). Results: The incidence of stroke was 3.9% (73/1886) over 35 months in this study. There were no significant differences in prevalence of established clinical risk-factors for stroke. There was a significantly higher prevalence of LV non-compaction (p =0.02), aneurysm (p <0.01), spontaneous echo-contrast (p <0.01) and pulmonary hypertension (p <0.001) in GpI. Conclusions: LV non-compaction, aneurysm, spontaneous echo-contrast and pulmonary hypertension are associated with an increased risk of stroke. While anticoagulation of these high-risk subgroups appears reasonable, further study in a prospective randomized clinical trial merits consideration. [ABSTRACT FROM AUTHOR]

Abstract: Background and purpose: Congestive heart failure is a risk factor for ischemic stroke. Brain natriuretic peptide (BNP) is used as a biological marker of heart failure. We hypothesized that heart failure was associated with the onset of ischemic stroke patients with atrial fibrillation (AF). Methods: Between June 2006 and December 2007, we prospectively enrolled consecutive acute ischemic stroke patients with AF within 24 h of onset. Plasma BNP was measured twice, on admission and on days 28 or at discharge. As a control, we measured plasma BNP of chronic phase of stroke outpatients with AF. We investigated whether plasma BNP was elevated in the acute phase of stroke. Results: One hundred and nine patients (58 females; mean age, 76.3 years) were enrolled in the present study. Mean±SD of NIHSS score on admission and mRS score at discharge were 12.6±8.3 and 3.7±1.8, respectively. The interval from stroke onset to plasma BNP measurement on admission was 6.8±6.3 h. Moreover, follow up BNP was measured at mean of 26±9 days after stroke onset. The plasma BNP level in the acute phase of stroke was significantly higher than that of the subacute phase of stroke (median (interquartile range, IQR) 299.0 (176.8–469.5) vs. 149.5 (68.1–347.0) pg/ml, p <0.001). There was no significant difference in plasma BNP level between the subacute phase of stroke and control group (median (IQR) 149.5 (68.1–347.0) vs. 165.0 (64.6–224.0) pg/ml, p =0.543). Conclusion: Plasma BNP was elevated in the acute phase of stroke. Heart failure may be associated with the onset of ischemic stroke patients with AF. [Copyright &y& Elsevier]

Abstract: Patients with atrial fibrillation are at an increased risk of having a cardioembolic stroke. Most of the thrombi responsible for these ischemic events originate in the left atrial appendage (LAA). Several surgical and percutaneous endovascular techniques have been explored to occlude the LAA. As an alternative of the surgical closure, percutaneous exclusion of the LAA is a new approach used to prevent strokes in high-risk patients with AF and contraindication to long-term oral anticoagulant therapy. Currently, two devices have been developed specifically for percutaneous occlusion of the LAA the PLAATO system and the WATCHMAN filter system. Although the Amplatzer septal occluder device was not originally intended to occlude the LAA it has been used with success in our centre for this purpose. We present an illustrative case of a patient with AF no longer suitable for chronic OCA referred for percutaneous exclusion of the LAA. She was treated successfully with an Amplatzer septal occluder. Although our experience with this device holds promise, future trials will be necessary to explore this strategy. [Copyright &y& Elsevier]