Validation of the CHADS2 clinical prediction rule to predict ischaemic stroke

The CHA2DS2-VASc score as a predictor of left atrial thrombus in patients with non-valvular atrial fibrillation

OBJECTIVE

To investigate whether or not the CHA2DS2-VASc score predicts left atrial (LA) thrombus detected on pre-cardioversion transoesophageal echocardiography (TEE).

MATERIALS AND METHODS

The medical records of patients who had undergone TEE were reviewed to assess the presence of LA thrombus prior to direct-current cardioversion for atrial fibrillation (AF). The CHA2DS2-VASc score was calculated for each patient. Clinical TEE reports were reviewed for the presence of LA thrombus. Patients with a valve prosthesis or rheumatic mitral valve disease were excluded from this study.

RESULTS

A total of 309 patients were identified. The mean age was 70.1 ± 9.8 years and 151 (49%) patients were males and 158 (51%) were females. LA thrombus was seen in 32 (10.3%) of the 309 patients. Fifty (16.2%) patients had a low CHA2DS2-VASc score (0-1), 230 (74.4%) had an intermediate score (2-4) and 29 (9.4%) had a high score (5-9). The incidence of LA thrombus in the low, intermediate and high CHA2DS2-VASc score groups was 0, 4.4 and 68.7%, respectively. The LA thrombus risk increased with increasing CHA2DS2-VASc scores. On multivariate logistic analysis, the CHA2DS2-VASc score (OR 3.26, 95% CI 2.3-4.65; p = 0.001) and age (OR 0.93, 95% CI 0.88-0.98; p = 0.004) were independent risk factors for LA thrombus in patients with non-valvular AF.

CONCLUSION

A high CHA2DS2-VASc score was independently associated with the presence of LA thrombus in patients with non-valvular AF.

Risk of stroke and oral anticoagulant use in atrial fibrillation: a cross-sectional survey

BACKGROUND

Oral anticoagulants substantially reduce the risk of stroke in atrial fibrillation but are underutilised in current practice.

AIM

To measure the distribution of stroke risk in patients with atrial fibrillation (using the CHADS(2) and CHA(2)DS(2)-VASc scores) and changes in oral anticoagulant use during 2007-2010.

DESIGN AND SETTING

Longitudinal series of cross-sectional survey in 583 UK practices linked to the QResearch(®) database providing 99 351 anonymised electronic records from people with atrial fibrillation.

METHOD

The proportion of patients in each CHADS(2) and CHA(2)DS(2)-VASc risk band in 2010 was calculated; for each of the years 2007-2010, the proportions with risk scores ≥2 that were using anticoagulants or antiplatelet agents were estimated. The proportions identified at high risk were re-estimated using alternative definitions of hypertension based on coded data. Finally, the prevalence of comorbid conditions in treated and untreated high-risk (CHADS(2) ≥2) groups was derived.

RESULTS

The proportion at high risk of stroke in 2010 was 56.9% according to the CHADS(2) ≥2 threshold, and 84.5% according to CHA(2)DS(2)-VASc ≥2 threshold. The proportions of these groups receiving anticoagulants were 53.0% and 50.7% respectively and increased during 2007-2010. The means of identifying the population of individuals with hypertension significantly influenced the estimated proportion at high risk. Comorbid conditions associated with avoidance of anticoagulants included history of falls, use of nonsteroidal anti-inflammatory drugs, and dementia.

CONCLUSION

Oral anticoagulant use in atrial fibrillation has increased in UK practice since 2007, but remains suboptimal. Improved coding of hypertension is required to support systematic identification of individuals at high risk of stroke and could be assisted by practice-based software.

Comparative assessment of published atrial fibrillation stroke risk stratification schemes for predicting stroke, in a non-atrial fibrillation population: the Chin-Shan Community Cohort Study

BACKGROUND

In patients at high risk of stroke, such as atrial fibrillation (AF), there has been great interest in developing stroke risk prediction schemes for identifying those at high risk of stroke. Stroke risk prediction schemes have also been developed in non-AF populations, but are limited by lack of simplicity, which is more evident in schemes used in AF populations. We hypothesized that contemporary stroke risk stratification schemes used in assessing AF patients could predict stroke and thromboembolism in a non-AF community population, comparably to that seen in AF populations.

METHODS

We tested the CHADS2 and CHA2DS2-VASc schemes, as well as the AF stroke risk stratification schemes from the Framingham study, Rietbrock et al., 2006 ACC/AHA/ESC guidelines, the 8th American College of Cardiology (ACCP) guidelines and NICE, for predicting stroke in a large community cohort of non-AF subjects, the Chin-Shan Community Cohort Study.

RESULTS

The tested schemes had variable classification into low, moderate and high risk strata, with the proportion classified as low risk ranging from 5.4% (Rietbrock et al. to 59.0% (CHADS2 classical). Rates of stroke also varied in those classified as 'low risk' ranging from 1.1% (Rietbrock et al. to 3.5% (Framingham). All common risk schemes had broadly similar c-statistics, ranging from 0.658 (Framingham) to 0.728 (CHADS2 classical) when assessed as a continuous risk variable for predicting stroke in this population, with clear overlap between the 95% CIs. In an exploratory analysis amongst AF subjects in our population, the c-statistics were broadly similar to those seen in non-AF subjects.

CONCLUSION

Contemporary stroke risk stratification schema used for AF can also be applied to non-AF populations with a similar (modest) predictive value. Given their simplicity (e.g. CHADS2 score), these scores could potentially be used for a 'quick' evaluation of stroke risk in non-AF populations, in a similar manner to AF populations.

A comparison of clinical characteristics and long-term prognosis in asymptomatic and symptomatic patients with first-diagnosed atrial fibrillation: the Belgrade Atrial Fibrillation Study

BACKGROUND

To investigate baseline characteristics and long-term prognosis of carefully characterized asymptomatic and symptomatic patients with atrial fibrillation (AF) in a 'real-world' cohort of first-diagnosed non-valvular AF over a 10-year follow-up period.

METHODS AND RESULTS

We conducted an observational, non-interventional, and single-centre registry-based study of consecutive first-diagnosed AF patients. Of 1100 patients (mean age 52.7±12.2 years and mean follow-up 9.9±6.1 years), 146 (13.3%) had asymptomatic AF. Persistent or permanent AF, slower ventricular rate during AF (<100/min), CHA2DS2-VASc score of 0, history of diabetes mellitus and male gender were independent baseline risk factors for asymptomatic AF presentation (all p<0.01) with a good predictive ability of the multivariable model (c-statistic 0.86, p<0.001). Kaplan-Meier 10-year estimates of survival free of progression of AF (log-rank test=33.4, p<0.001) and ischemic stroke (log-rank test=6.2, p=0.013) were significantly worse for patients with asymptomatic AF compared to those with symptomatic arrhythmia. In the multivariable Cox regression analysis, intermittent asymptomatic AF was significantly associated with progression to permanent AF (Hazard Ratio 1.6; 95% CI, 1.1-2.2; p=0.009).

CONCLUSIONS

In a 'real-world' setting, patients with asymptomatic presentation of their first-diagnosed AF could have different risk profile and long-term outcomes compared to those with symptomatic AF. Whether more intensive monitoring and comprehensive AF management including AF ablation at early stage following the incident episode of AF and increased quality of oral anticoagulation could alter the long-term prognosis of these patients requires further investigation.

Atherosclerosis and thromboembolic risk in atrial fibrillation: focus on peripheral vascular disease

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. It results in a 5-fold increased risk for stroke and thromboembolism and is associated with a high morbidity and mortality. AF shares several risk factors and pathophysiological features with atherosclerosis. Hence AF is often complicated by a variety of other cardiovascular conditions. Indeed, peripheral vascular disease (PVD) is highly prevalent among AF patients and associates with increased mortality. Inclusion of PVD within stroke risk scoring systems such as the CHA2DS2-VASc score improves risk stratification of AF patients. Of note, PVD has not been previously well documented nor looked for in observational studies or clinical trials. The aim of this present review article is to provide an overview of the association between atherosclerosis (with particular focus on PVD) and AF as well as its complications.

Factors that influence awareness and treatment of atrial fibrillation in older adults

AIM

The aims of this study were to investigate the prevalence of atrial fibrillation (AF), treatment rates of AF and the factors underlying awareness and treatment, in a large nationally representative study.

METHODS

A population sample of people aged 50+, living in the Republic of Ireland, were recruited as part of The Irish longitudinal study on ageing. Ten-minute electrocardiogram recordings were obtained (n = 4890), and analysed to detect AF. Self-reported arrhythmias, subjective and objective health measures (cardiovascular diseases, CHA2DS2-VASc variables and blood pressure) and medications were also recorded. Logistic regressions were used to determine associations with outcomes of presence of AF, lack of awareness and untreated AF.

RESULTS

Overall prevalence of AF was 3% (95% CI: 2.4-3.7%), with a marked age gradient and sex difference [4.8% (men) vs. 1.4% (women); P < 0.0001]. In total, 67.8% were at high risk of stroke (CHA2DS2-VASc ≥ 2), of whom 59.3% were inadequately treated. A high proportion of 38.1% were unaware of having AF. CHA2DS2-VASc nor HAS-BLED score influenced awareness or treatment. Lack of awareness was associated with lower education (P = 0.01), lower cognition (P = 0.04), rural location (OR = 3.67; P = 0.02) and number of general practitioner visits (P = 0.01), whereas untreated AF was influenced by frailty status (P = 0.04).

CONCLUSION

With projected doubling of numbers of persons over 80 in the next 30 years in the British Isles, detection and management of AF is pressing. Two-thirds of adults at high risk of stroke were inadequately treated. More regular screening for AF, application of criteria for stroke and bleeding risk and awareness of factors influencing diagnosis and treatment is recommended.

Review of challenges in optimizing oral anticoagulation therapy for stroke prevention in atrial fibrillation

Oral anticoagulant therapy is the mainstay of stroke prevention in patients with atrial fibrillation; it is highly effective at reducing stroke risk, but its use can be limited by increased risk of bleeding. As new oral anticoagulants are available, barriers to optimal use of oral anticoagulation therapy warrant consideration by healthcare professionals and administrators who are seeking to optimize the quality of care for patients with atrial fibrillation. Suboptimal use of oral anticoagulation therapy constitutes an important health problem with significant humanistic and economic consequences. Based on a review of the medical literature published between 2000 and 2011, this article summarizes the literature on the barriers to optimal use of oral anticoagulation therapy, describes the clinical and economic burdens that these barriers add to the burden of atrial fibrillation, and discusses how well the new oral anticoagulants may address some of these issues.

Recommendations for thromboprophylaxis in the 2012 focused update of the ESC guidelines on atrial fibrillation: a commentary

The objective of this article is to provide a commentary on the recommendations for stroke prevention from the 2012 focused update of the European Society of Cardiology guidelines on the management of atrial fibrillation and the evidence (or lack of it) supporting these recommendations. These guidelines strongly advocate a major clinical practice shift towards initially focusing on the identification of 'truly low risk' patients who do not need any antithrombotic therapy. After this initial decision-making step, effective stroke prevention - that is, oral anticoagulation therapy (whether as well-controlled adjusted dose warfarin or with one of the novel oral anticoagulants) - could be offered to patients with atrial fibrillation with ≥ 1 stroke risk factors. The 2012 focused update guideline also provides additional guidance on advances in stroke and bleeding risk assessment that are evident since publication of the 2010 guideline, as well as recommendations on the use of the novel oral anticoagulants and the left atrial appendage occlusion devices that have been increasingly used in European clinical practice over the last 2 years.

Antithrombotic therapy for stroke prevention in non-valvular atrial fibrillation

The world faces an epidemic of atrial fibrillation and atrial fibrillation-related stroke. An individual's risk of atrial fibrillation-related stroke can be estimated with the CHADS(2) or CHA(2)DS(2)VASc scores, and reduced by two-thirds with effective anticoagulation. Vitamin K antagonists, such as warfarin, are underused and often poorly managed. The direct thrombin inhibitor dabigatran etexilate and factor Xa inhibitors rivaroxaban and apixaban are new oral anticoagulants that are at least as efficacious and safe as warfarin. Their advantages are predictable anticoagulant effects, low propensity for drug interactions, and lower rates of intracranial haemorrhage than with warfarin. A disadvantage is the continuing need to develop and validate rapidly effective antidotes for major bleeding and standardised tests that accurately measure plasma concentrations and anticoagulant effects, together with the disadvantage of possible higher rates of gastrointestinal haemorrhage and greater expense than with warfarin. The new oral anticoagulants should increase the number of patients with atrial fibrillation at risk of stroke who are optimally anticoagulated, and reduce the burden of atrial fibrillation-related stroke.

One-year clinical prediction in Chinese ischemic stroke patients using the CHADS2 and CHA2DS2-VASc scores: the China National Stroke Registry

AIMS

We investigated whether CHADS2 or CHA2DS2-VASc scores could be used to predict 1-year prognosis in stroke recurrence, mortality, and mortality of ischemic stroke or transient ischemic attack (TIA) patients with nonvalvular atrial fibrillation (NVAF).

METHODS

Patients were selected from a national prospective registry in China. The clinical prediction of the scores was examined using the C statistic. Univariate and multivariate logistic regressions were performed to analyze the relevant risk factors.

RESULTS

Thousand two hundred and ninety-seven of 22,216 patients were enrolled in the study. For stroke recurrence rate, the C statistic value was 0.53 (odds ratio [OR] 1.15, 95% confidence interval [CI]: 1.01 to 1.32) for CHADS2 and 0.55 (OR 1.14, 95% CI: 1.05 to 1.24) for CHA2DS2-VASc; adding baseline National Institutes of Health Stroke Scale (NIHSS) score to these two scores, the value of C statistic was 0.58 (OR 1.25 95% CI: 1.14 to 1.37) and 0.58 (OR 1.19, 95% CI: 1.11 to 1.27), respectively.

CONCLUSIONS

Both CHADS2 and CHA2DS2-VASc scores have limitations in predicting the 1-year prognosis of stroke/TIA patients with NVAF in China. The predictive value of these two scores improved by adding the baseline NIHSS score.

Ankle brachial index as an independent predictor of mortality in anticoagulated atrial fibrillation

BACKGROUND

An abnormal ankle brachial index (ABI, the ratio of the ankle and the brachial systolic blood pressure) (≤ 0·90 or ≥ 1·4) suggests the presence of peripheral arterial disease (PAD) and has proposed as a marker of cardiovascular risk. We hypothesised that the ABI would predict mortality and adverse events in anticoagulated chronic nonvalvular AF patients.

METHODS

We recruited 287 consecutive anticoagulated outpatients with permanent or paroxysmal nonvalvular AF who were stabilised for 6 months on oral anticoagulation (Oral anticoagulation; INR 2·0-3·0). ABI was performed following a standard technique. Cox models were used to determine the association between ABI, and bleeding, cardiovascular events and mortality.

RESULTS

Median ABI was 1·09 (0·93-1·23) and 78 (27%) had an abnormal ABI. Abnormal ABI was associated with diabetes, heart failure and ischaemic heart disease (P = 0·006, 0·019 and 0·009, respectively), and a CHADS(2) score ≥ 2 (P = 0·016). Median follow-up was 861 (718-1016) days, during 21(7%) presented an adverse cardiovascular event, 23 (8%) major bleeding events and 18 (6%) died. ABI was an independent predictor for all-cause mortality, even after adjusting for CHADS(2) score (Cox multivariable regression analysis, HR 2·76(1·08-7·06), P = 0·033). Abnormal ABI was significantly associated with major haemorrhagic events [HR: 2·47(1·01-6·04); P = 0·047], even after adjustment for HAS-BLED score.

CONCLUSION

Abnormal ABI is common in AF patients, and ABI was an independent predictor for all-cause mortality, even after adjusting for CHADS(2) score. ABI was an independent predictor for major bleeding, even after adjusting for the HAS-BLED score. ABI could be a useful tool for improving risk stratification of anticoagulated AF patients.

Target-specific oral anticoagulants for stroke prevention in patients with atrial fibrillation: real-world considerations

Target-specific oral anticoagulants are now available for the prevention of stroke in patients with atrial fibrillation. These medications have many advantages, including fixed dosing, predictable anticoagulation without the need for monitoring, and few food or drug interactions. On the down side, their anticoagulant effects cannot be readily measured in clinical practice, and there are no known antidotes to reverse their anticoagulant effects. Clinical trials have shown superiority or noninferiority of these anticoagulants when compared with warfarin for reduction in incidence of stroke or systemic embolism, major bleeding, and mortality rates. Based on these findings, recent guidelines have supported the use of dabigatran compared with warfarin (other agents were not included in the guideline). Yet, there are concerns that these new agents may not be appropriate for all patients. Patients who are on warfarin and have stable and therapeutic anticoagulation may see no improvement in outcomes if changed to one of the new anticoagulants. Patients with decreased renal function may be at increased risk for bleeding if deterioration in renal function occurs. Management of bleeding events is complicated by the inability to reverse the new medications' anticoagulant effects. Medication noncompliance may result in more adverse outcomes due to the short half-life of these agents compared with warfarin. Prescribers need to be aware of these limitations as these medications are incorporated into clinical practice. Patients and clinicians need to understand the risk and benefits, and patients need to be engaged with their health care providers in decision making.

Outcomes associated with warfarin use in older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device: findings from the ADHERE registry linked to Medicare claims

BACKGROUND

Warfarin use and associated outcomes in patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device have not been described previously.

HYPOTHESIS

We hypothesized that warfarin is underused and is associated with lower risks of mortality, thromboembolic events, and myocardial infarction.

METHODS

Using data from a clinical registry linked with Medicare claims, we examined warfarin use at discharge and 30-day and 1-year Kaplan-Meier estimates of all-cause mortality and cumulative incidence rates of mortality, thromboembolic events, myocardial infarction, and bleeding events in patients 65 years or older, with a history of atrial fibrillation and a cardiovascular implantable electronic device admitted with heart failure between 2001 and 2006, who were naïve to anticoagulation therapy at admission. We compared outcomes between patients who were or were not prescribed warfarin at discharge and tested associations between treatment and outcomes.

RESULTS

Of 2586 eligible patients in 252 hospitals, 2049 were discharged without a prescription for warfarin. At 1 year, the group discharged without warfarin had a higher mortality rate after discharge (37.4% vs 28.8%; P < 0.001) but similar rates of thromboembolism, myocardial infarction, and bleeding events. After adjustment, treatment with warfarin was associated with lower risk of all-cause death 1 year after discharge (hazard ratio: 0.76, 95% confidence interval: 0.63-0.92).

CONCLUSIONS

Among older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device, 4 of 5 were discharged without a prescription for warfarin. Warfarin nonuse was associated with a higher risk of death 1 year after discharge. Clin. Cardiol. 2011 DOI: 10.1002/clc.22064 Damon M. Seils, MA, Duke University, assisted with manuscript preparation. Mr. Seils did not receive compensation for his assistance apart from his employment at the institution where the study was conducted. This study was supported by a research agreement between Duke University and Janssen Pharmaceuticals. The authors have no other funding, financial relationships, or conflicts of interest to disclose.

The risk stratification in atrial fibrillation

Atrial fibrillation (AF) is the most common rhythm disorder and represents a major public health problem because it carries an increased risk of arterial thromboembolism and ischemic stroke. Because the absolute benefit of antithrombotic therapy depends on the underlying risk of stroke, an accurate stratification of patients' risk is needed to choose the appropriate antithrombotic strategy. Over the years, several stroke risk stratification models (RSMs) were developed based on the 'classic' risk factors for stroke such as increasing age, hypertension, diabetes mellitus, and left ventricular dysfunction. Among all RSMs, the CHADS(2) score is the most popular and used one thanks to its simplicity and endorsement in several widely promulgated practice guidelines. Despite its validation in large datasets and specific population of AF patients, it has many limitations, especially due to the non-inclusion of several proven risk factors for stroke and to the classification of a large number of patients in the intermediate risk category, so creating ambiguity over the most appropriate antithrombotic therapy. Thus, the CHA(2)DS(2)-VASc score was introduced and was demonstrated to perform better than the CHADS(2), even in a "real world" population of elderly AF patients. Recently, in view of the availability of new oral anticoagulant drugs, that can overcome the limitations of warfarin and allow a more personalized therapy, many efforts are being made to identify other possibilities to assess the thromboembolic risk in AF patients. It has been demonstrated that an increase in C-reactive protein and interleukin-6 and the presence of G20210A factor II gene polymorphism and hyper-homocysteinemia are independent risk factors for ischemic complications in AF patients. Even the presence of chronic renal disease and the daily AF burden, registered with implantable monitors, are associated with an increase risk of stroke. Finally, the assessment of thromboembolic risk should go hand in hand with the consideration of the risk of bleeding. For this purpose, it has been recently developed a practical bleeding risk score, the HAS-BLED, which was included in the last ESC guidelines for the risk stratification of AF patients before starting anticoagulant therapy.

Prognostic value of the CAPRA clinical prediction rule: a systematic review and meta-analysis

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Prostate cancer is a significant cause of mortality among men. A number of prognostic instruments exist to predict the risk of recurrence among patients with localised prostate cancer. This systematic review examines the totality of evidence in relation to the predictive value of the CAPRA clinical predication rule by combining all studies that validate the rule.

OBJECTIVES

To perform a systematic review with meta-analysis that assesses the 3- and 5-year predictive value of the CAPRA rule, a clinical prediction rule derived to predict biochemical-recurrence-free survival in men with localized prostate cancer after radical prostatectomy. To examine the predictive value of the CAPRA rule at 3 and 5 years stratified by risk group (0-2 low risk, 3-5 intermediate risk, 6-10 high risk).

PATIENTS AND METHODS

A systematic literature search was performed to retrieve papers that validated the CAPRA score. The original derivation study was used as a predictive model and applied to all validation studies with observed and predicted biochemical-recurrence-free survival at 3 and 5 years stratified by risk group (0-2 low, 3-5 intermediate, 6-10 high). Pooled results are presented as risk ratios (RRs) with 95% confidence intervals, in terms of over-prediction (RR > 1) or under-prediction (RR < 1) of biochemical-recurrence-free survival at 3 and 5 years. A chi-squared test for trend was computed to determine if there was a decreasing trend in survival across the three CAPRA risk categories.

RESULTS

Seven validation studies (n = 12 693) predict recurrence-free survival at 5 years after radical prostatectomy. The CAPRA score significantly under-predicts recurrence-free survival across all three risk strata (low risk, RR 0.94, 95% CI 0.90-0.98; intermediate risk, RR 0.94, 95% CI 0.89-0.99; high risk, RR 0.72, 95% CI 0.60-0.85). Data on six studies (n = 6082) are pooled to predict 3-year recurrence-free survival. The CAPRA score correctly predicts recurrence-free survival in all three groups (low risk, RR 0.98, 95% CI 0.95-1.00; intermediate risk, RR 1.03, 95% CI 0.99-1.08; high risk, RR 0.87, 95% CI 0.73-1.05). The chi-squared trend analysis indicates that, as the trichotomized CAPRA score increases, the probability of survival decreases (P < 0.001).

CONCLUSIONS

The results of this pooled analysis confirm the ability of the CAPRA rule to correctly predict biochemical-recurrence-free survival at 3 years after radical prostatectomy. The rule under-predicts recurrence-free survival 5 years after radical prostatectomy across all three strata of risk.

Atrial fibrillation, stroke, and quality of life

Contemporary management of atrial fibrillation imposes many challenges, particularly in the setting of our aging population. In addition to well-recognized consequences, such as stroke and mortality, emerging evidence relates atrial fibrillation to elevated risk of dementia, posing further therapeutic challenges. As the incidence of atrial fibrillation rises with age, the balance of controlling stroke risk and limiting major hemorrhage on anticoagulation has become increasingly critical in elderly patients. Appreciation of more extensive risk factors has made it possible to identify patients at very low risk of thromboembolism and higher risk of bleeding. However, practice guidelines in the United States and abroad have occasionally divergent viewpoints regarding how to best manage patients in various risk strata. Options for stroke prevention have expanded with novel antithrombotics and promising mechanical alternatives to anticoagulation, which may be at least as effective in preventing stroke without increasing bleeding risk. Catheter ablation has demonstrated impressive success at preventing atrial fibrillation recurrence in selected patients, and has the potential to further improve outcomes. In addition, the role of antiplatelet medications in patients deemed unsuitable for anticoagulation has been better clarified, although novel agents require further study to assess their impact on thromboembolism. High-bleeding risks associated with the concomitant use of multiple antithrombotics remains a major obstacle in patients with indications for both antiplatelet and anticoagulant therapy.

Predictive value of the CHA2DS2-VASc score in atrial fibrillation patients at high risk for stroke despite oral anticoagulation

INTRODUCTION AND OBJECTIVES

The risk of stroke in atrial fibrillation is heterogeneous and depends upon underlying clinical conditions included in current risk stratification schemes. Recently, the CHA(2)DS(2)-VASc score has been included in guidelines to be more inclusive of common stroke risk factors seen in everyday clinical practice, and useful in defining "truly low risk" subjects. We aimed to assess the usefulness of CHA(2)DS(2)-VASc score to give us an additional prognostic perspective for adverse events and mortality among "real world" anticoagulated patients with atrial fibrillation who are often elderly with many comorbidities.

METHODS

Consecutive outpatients with permanent/paroxysmal nonvalvular atrial fibrillation with CHA(2)DS(2)-VASc≥2 and stabilized oral anticoagulation (international normalized ratio 2.0-3.0) for at least the preceding 6 months were recruited. Patients with CHA(2)DS(2)-VASc≥2 were selected. Adverse cardiovascular events including stroke, acute coronary syndrome, or heart failure; major bleeds; and mortality were recorded during more than 2.5-year-follow-up.

RESULTS

Of 933 patients (93.5%) assessed, 432 were males, median age 76 (71-81) years. After a follow-up of 946 (782-1068) days, 109 patients (11.7%) had adverse cardiovascular events, 80 patients (8.6%) had major bleeds, 101 patients (10.8%) died, and 230 (24.6%) had major adverse events (composite end-point). Increasing CHA(2)DS(2)-VASc score by 1 point had a significant impact on the occurrence of cardiovascular events (hazard ratio=1.27; 95% confidence interval, 1.13-1.44; P<.001), mortality (hazard ratio=1.36; 95% confidence interval, 1.19-1.54; P<.001); and major adverse events (hazard ratio=1.23; 95% confidence interval, 1.13-1.34; P<.001). CHA(2)DS(2)-VASc score was not associated with major bleeding episodes.

CONCLUSIONS

Among high risk atrial fibrillation patients on oral anticoagulation, CHA(2)DS(2)-VASc successfully predicts cardiovascular events and mortality, but not major bleeds.

The value of the CHA2DS2-VASc score for refining stroke risk stratification in patients with atrial fibrillation with a CHADS2 score 0-1: a nationwide cohort study

North American and European guidelines on atrial fibrillation (AF) are conflicting regarding the classification of patients at low/intermediate risk of stroke. We aimed to investigate if the CHA2DS2-VASc score improved risk stratification of AF patients with a CHADS2 score of 0-1. Using individual-level-linkage of nationwide Danish registries 1997-2008, we identified patients discharged with AF having a CHADS2 score of 0-1 and not treated with vitamin K antagonist or heparin. In patients with a CHADS2 score of 0, 1, and 0-1, rates of stroke/ thromboembolism were determined according to CHA2DS2-VASc score, and the risk associated with increasing CHA2DS2-VASc score was estimated in Cox regression models adjusted for year of inclusion and antiplatelet therapy. The value of adding the extra CHA2DS2-VASc risk factors to the CHADS2 score was evaluated by c-statistics, Net Reclassification Improvement (NRI) and Integrated Discrimination Improvement (IDI). We included 47,576 patients with a CHADS2 score of 0-1, from these 7,536 (15.8%) were CHA2DS2-VASc score=0, 10,062 (21.2%) were CHA2DS2-VASc score=1, 14,310 (30.1%) were CHA2DS2-VASc score=2, 14,188 (29.8%) were CHA2DS2-VASc score=3, and 1,480 (3.1%) were CHA2DS2-VASc score=4. Of the cohort with a CHADS2 score of 0-1, the stroke/thromboembolism rate per 100 person-years increased with increasing CHA2DS2-VASc score (95% confidence interval): 0.84 (0.65-1.08), 1.79 (1.53-2.09), 3.67 (3.34-4.03), 5.75 (5.33-6.21), and 8.18 (6.68-10.02) at one year follow-up with CHA2DS2-VASc scores of 0, 1, 2, 3, and 4, respectively. Patients with a CHADS2 score=0 were not all 'low risk', with one-year event rates ranging from 0.84 (CHA2DS2-VASc score=0) to 3.2 (CHA2DS2-VASc score=3). Results from Cox regression analyses, NRI, and IDI confirmed the improved predictive ability of the CHA2DS2-VASc score in the AF patients who have a CHADS2 score of 0-1. In conclusion, the CHA2DS2-VASc provides critical information on risk of stroke in AF patients with a CHADS2 score of 0-1 that can aid a decision of using anticoagulation. Even in patients categorised as 'low risk' using a CHADS2 score=0, the CHA2DS2-VASc score significantly improved the predictive value of the CHADS2 score alone and a CHA2DS2-VASc score=0 could clearly identify 'truly low risk' subjects. Use of the CHA2DS2-VASc score would significantly improve classification of AF patients at low and intermediate risk of stroke, compared to the commonly used CHADS2 score.

Aspirin in stroke prevention in nonvalvular atrial fibrillation and stable vascular disease: an era of new anticoagulants

Atrial fibrillation (AF) is a major cause of ischemic stroke, especially in the elderly. There are currently enough data to support the notion that anticoagulation with warfarin or dabigatran is far superior to aspirin in the prevention of stroke or systemic embolism in AF. Aspirin is the preferred modality in patients who are either not candidates for anticoagulation, such as patients with increased risk for bleeding, low-risk patients based on the CHADS2 score or patients who have difficulty in maintaining a therapeutic international normalized ratio. There is no dispute on the recommendations regarding stroke prevention in high-risk patients (CHADS2 risk score of 2 and beyond) with AF. However, there is some controversy regarding the appropriate strategy (anticoagulation vs aspirin) for stroke prevention in low-risk patients (CHA2DS2-VASc score of 0-1). Novel oral anticoagulant drugs (direct thrombin inhibitors and Factor Xa inhibitors) might further diminish the role of aspirin for stroke prevention in AF due to their superior efficacy, lack of need for monitoring of therapeutic effects and lower bleeding risk when compared with warfarin, especially in patients with stable vascular disease.

Prognosis in patients with atrial fibrillation and CHA2DS2-VASc Score = 0 in a community-based cohort study

OBJECTIVES

Patients with atrial fibrillation (AF) and a CHA(2) DS(2) -VASc score = 0 have a very low risk of stroke and current guidelines even recommend no antithrombotic therapy to these patients. We investigated the rate and risk of adverse events and the impact of antithrombotic management in a community based cohort of AF patients with a CHA(2)DS(2)-VASc score = 0.

METHODS AND RESULTS

Patients with AF seen in our institution between 2000 and 2010 were identified in a database. The adverse outcomes were investigated during follow-up. Among 8,962 patients with AF, 616 (7%) had a congestive heart failure, hypertension, age ≥75 years (doubled), diabetes, stroke/TIA/thromboembolism (doubled), vascular disease (prior myocardial infarction, peripheral artery disease, or aortic plaque), age 65-74 years, sex category (female) (CHA(2)DS(2)-VASc score) = 0. An oral anticoagulant was prescribed in 273 patients (44%), antiplatelet therapy alone in 145 patients (24%), and no antithrombotic treatment in 198 patients (32%). During a follow up of 876 ± 1,135 days (median 244, interquartile range 1,540 days), 38 patients sustained events (10 stroke/thromboembolism, 19 major bleeding, 17 deaths). Among untreated patients, rates of stroke/thromboembolism, major bleeding and mortality were 0.64%, 1.12%, and 1.08% per year. Prescription of oral anticoagulation and/or antiplatelet therapy was not associated with an improved prognosis for stroke/thromboembolism (relative risk [RR] = 0.99, 95% CI 0.25-3.99, P = 0.99), nor improved survival or net clinical benefit (combination of stroke/thromboembolism, bleeding, and death).

CONCLUSION

In a real life cohort study, AF patients with CHA(2)DS(2) VASc score = 0 had a low risk of stroke/thromboembolism that was not significantly different between those taking oral anticoagulation, antiplatelet therapy, or no antithrombotic therapy. This supports current guideline recommendations for no antithrombotic therapy in these "truly low-risk" patients.

Can we predict stroke in atrial fibrillation?

Stroke prevention with appropriate thromboprophylaxis still remains central to the management of atrial fibrillation (AF). Nonetheless, stroke risk in AF is not homogeneous, but despite stroke risk in AF being a continuum, prior stroke risk stratification schema have been used to 'artificially' categorise patients into low, moderate and high risk stroke strata, so that the patients at highest risk can be identified for warfarin therapy. Data from recent large cohort studies show that by being more inclusive, rather than exclusive, of common stroke risk factors in the assessment of the risk for stroke and thromboembolism in AF patients, we can be so much better in assessing stroke risk, and in optimising thromboprophylaxis with the resultant reduction in stroke and mortality. Thus, there has been a recent paradigm shift towards getting better at identifying the 'truly low risk' patients with AF who do not even need antithrombotic therapy, whilst those with one or more stroke risk factors can be treated with oral anticoagulation, whether as well-controlled warfarin or one or the new oral anticoagulant drugs. The new European guidelines on AF have evolved to deemphasise the artificial low/moderate/high risk strata (as they were not very predictive of thromboembolism, anyway) and stressed a risk factor based approach (within the CHA(2) DS(2)-VASc score) given that stroke risk is a continuum. Those categorised as 'low risk' using the CHA(2) DS(2)-VASc score are 'truly low risk' for thromboembolism, and the CHA(2) DS(2)-VASc score performs as good as-and possibly better--than the CHADS(2) score in predicting those at 'high risk'. Indeed, those patients with a CHA(2) DS(2)-VASc score = 0 are 'truly low risk' so that no antithrombotic therapy is preferred, whilst in those with a CHA(2) DS(2)-VASc score of 1 or more, oral anticoagulation is recommended or preferred. Given that guidelines should be applicable for >80% of the time, for >80% of the patients, this stroke risk assessment approach covers the majority of the patients we commonly seen in everyday clinical practice, and considers the common stroke risk factors seen in these patients. The European guidelines also do stress that antithrombotic therapy is necessary in all patients with AF unless they are age <65 years and truly low risk. Indeed, some patients with 'female gender' only as a single risk factor (but still CHA(2) DS(2)-VASc score of 1, due to gender) do not need anticoagulation, especially if they fulfil the criterion of "age <65 and lone AF, and very low risk". In the European and Canadian guidelines, bleeding risk assessment is also emphasised, and the simple validated HAS-BLED score is recommended. A HAS-BLED score of ≥ 3 represents a sufficiently high risk such that caution and/or regular review of a patient is needed. It also makes the clinician think of correctable common bleeding risk factors, and the availability of such a score allows an informed assessment of bleeding risk in AF patients, when antithrombotic therapy is being initiated.

A New Landscape for Stroke Prevention in Atrial Fibrillation

Background—

Worldwide, atrial fibrillation is the most common arrhythmia, and its symptoms and sequelae cause an enormous burden to patients and health systems. Stroke is associated with the greatest mortality and morbidity in patients with atrial fibrillation (AF). The last decade has seen great advances in scientific and therapeutic approaches to AF.

Purpose—

This review considers recent changes to stroke prevention, particularly focusing on new anticoagulants, antiarrhythmic drugs, and devices as well as future research directions.

Summary of Review—

A semi-systematic literature review was performed using search terms “atrial fibrillation” and “novel therapy” within the PubMed database from 2005 to 2011. The area of greatest progress has been novel anticoagulants with direct thrombin inhibitors and factor Xa inhibitors. Dabigatran is the only novel agent currently licensed for use in AF patients, but with several trials of novel agents pending and favorable results so far, other agents are likely to follow. Novel antiarrhythmic drugs, left atrial appendage occlusion, and upstream therapies all represent potential new approaches but require further research.

Conclusions—

Novel anticoagulant and arrhythmic agents are changing treatment guidelines and choices available to both patients and clinicians for stroke prevention in AF, but bring new considerations and long-term data are required, because most patients will require lifelong therapy. Future research must incorporate patient values and preferences, because novel therapies can potentially give very different treatment options, which must be explained for patients to make informed choices.