Validation of the CHADS2 clinical prediction rule to predict ischaemic stroke

Combination of platelet-to-lymphocyte ratio and D-dimer for the identification of cardiogenic cerebral embolism in non-valvular atrial fibrillation

Background

Non-valvular atrial fibrillation (NVAF) is the most common cause of cardiogenic cerebral embolism (CCE). However, the underlying mechanism between cerebral embolism and NVAF is indefinite, and there is no effective and convenient biomarker to identify potential risk of CCE in patients with NVAF in clinic. The present study aims to identify risk factors for interpreting the potential association of CCE with NVAF and providing valuable biomarkers to predict the risk of CCE for NVAF patients.

Methods

641 NVAF patients diagnosed with CCE and 284 NVAF patients without any history of stroke were recruited in the present study. Clinical data including demographic characteristics, medical history, and clinical assessments, were recorded. Meanwhile, Blood cell counts, lipid profiles, high-sensitivity C-reactive protein, and coagulation function-related indicators were measured. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to build a composite indicator model based on the blood risk factors.

Results

(1) CCE patients had significantly increased neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), and D-dimer levels as compared with patients in the NVAF group, and these three indicators can distinguish CCE patients from ones in the NVAF group with an area under the curve (AUC) value of over 0.750, respectively. (2) Using the LASSO model, a composite indicator, i.e., the risk score, was determined based on PLR and D-dimer and displayed differential power for distinguishing CCE patients from NVAF patients with an AUC value of over 0.934. (3) The risk score was positively correlated with the National Institutes of Health Stroke Scale and CHADS2 scores in CCE patients. (4) There was a significant association between the change value of the risk score and the recurrence time of stroke in initial CCE patients.

Conclusions

The PLR and D-dimer represent an aggravated process of inflammation and thrombosis in the occurrence of CCE after NVAF. The combination of these two risk factors can contribute to identifying the risk of CCE for patients with NVAF with an accuracy of 93.4%, and the greater in change of composite indicator, the shorter in the recurrence of CCE for NVAF patients.

The effects of apixaban on clot characteristics in atrial fibrillation: A novel pharmacodynamic biomarker

Atrial fibrillation (AF) is a major risk factor for stroke. We aim to characterize AF patients and the effects of apixaban therapy in terms of clot microstructure using gel point analysis, a novel biomarker. Seventy-eight patients were included in the study, 50 Stroke with AF (AF-S), and 28 AF without stroke (AF). Pre- and post-anticoagulation samples were collected: gel point (GP) analysis was performed to obtain (i) TGP (the time taken to reach the GP or the clot formation time) and (ii) d_{f ,} the fractal dimension of the clot, a quantification of clot fibrin microstructure at the GP. At baseline, the AF-S group had a d_f  = 1.70 (±0.05) and TGP = 306 (±73 s). The AF group had a df = 1.70 ± 0.05 and TGP = 346 ± 78 s, showing a significantly shortened TGP in the stroke group (p = .008). For both groups, apixaban significantly prolonged TGP, p = .005, but resulted in no change in df. Apixaban prolonged clotting time while having no significant impact on the blood's ability to form stable clots (no change in d_f ). This indicates that apixaban provides protection from the formation of thrombi by reducing clotting kinetics.

Cryptogenic Stroke and Embolic Stroke of Undetermined Source: Risk Factors and Approaches for Detection of Atrial Fibrillation

BACKGROUND

Stroke is a problem worldwide because of its high mortality and disability rates. Almost 90% of strokes are ischemic, and more than half of the deaths are caused by an ischemic stroke. Most risk factors for stroke are manageable so that it can be avoided with proper prevention. Despite the success in determining the causes of stroke in recent years, selectively, the "culprit" causing stroke remains unsolved. In such cases, a diagnosis of undetermined etiology (cryptogenic stroke) or embolic stroke of undetermined source (ESUS) is generated, resulting the prevention of a recurrent cerebrovascular occurrence impossible. Atrial fibrillation (AF) can be a cause of stroke by causing blood clots in the chambers of the heart.

PURPOSE

The aim was to determine the optimal method of heart rate monitoring in patients with ischemic stroke, as methods and approaches for detecting AF are very diverse, but there is still no single opinion, which would be universal.

PROCEDURES

In our review, we consider epidemiology, risk factors for the stroke of undetermined etiology, as well as analytical methods for detecting heart rhythm disturbances in this category of patients.

FINDINGS

Atrial fibrillation (AF) is detected by thorough monitoring of heart rate of patients with cryptogenic stroke and ESUS can be diagnosed in up to 46% of patients. .

CONCLUSION

After AF detection, consideration should be given to prescribing anticoagulants, instead of antiplatelet agents, for the secondary prevention of stroke.

CHA2DS2-VASc Score and In-Hospital Mortality in Critically Ill Patients With New-Onset Atrial Fibrillation

OBJECTIVE

To examine the role of the CHA₂DS₂-VASc (Congestive heart failure; Hypertension; Age ≥75 years [doubled]; Diabetes; previous Stroke, transient ischemic attack, or thromboembolism [doubled]; Vascular disease; Age 65-75 years; and Sex category) score as a prognostic marker of in-hospital mortality in critically ill patients who develop new-onset atrial fibrillation (NOAF).

DESIGN

Retrospective analyses.

SETTING

A single-center study in a tertiary care academic medical center.

PARTICIPANTS

The study comprised all adult patients with NOAF admitted to noncardiac intensive care units (ICUs) at a tertiary care academic institution between January 2009 and March 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors retrospectively reviewed electronic medical records of all adult patients admitted to noncardiac ICUs at a tertiary care academic institution between January 2009 and March 2016. Patients with NOAF were identified and their CHA₂DS₂-VASc score was calculated. The authors evaluated the association of CHA₂DS₂-VASc score and its individual components with in-hospital mortality in these patients. A total of 640 (1.7% [38,708 patients]; 95% CI 1.5%-1.8%) patients developed NOAF during the study period. The in-hospital mortality rate in patients included in the analysis was 14.3%. There was no association between in-hospital mortality and CHA₂DS₂VASc score. However, the likelihood of in-hospital death was 1.56  times greater for patients having atrial fibrillation and concomitant vascular disease (95% CI 1.003-2.429; p = 0.049).

CONCLUSIONS

New-onset atrial fibrillation is common in critically ill patients and is associated with high in-hospital mortality. The authors found that the CHA₂DS₂-VASc score itself is not a reliable prognostic marker of in-hospital mortality in these patients. However, the presence of vascular disease in patients with NOAF may increase the mortality associated with this disease.

Multimodality imaging for thromboembolic risk assessment in atrial fibrillation

: Atrial fibrillation is the most widely represented sustained arrhythmia in the world. Thromboembolic risk assessment represents the main clinical challenge associated with this condition, requiring enormous medical, social and economical efforts. Several pieces of evidence in literature highlight how clinical risk factors are not enough for a correct thromboembolic risk stratification of patients with atrial fibrillation, since thromboembolic events have been proven to occur even in patients with low clinical risk scores. A comprehensive multimodality imaging approach, with special regard to echocardiography and new technologies seems to be the best method for this purpose. The aim of this review is to propose a hybrid thromboembolic risk stratification system that combinines clinical evaluation with instrumental clues on left atrial remodeling, fibrosis and deformation which, could be useful especially for patients classified at low thromboembolic risk according to clinical scores.

Left Atrial Appendage Occlusion, Shared Decision-Making, and Comprehensive Atrial Fibrillation Management

The epidemic of atrial fibrillation (AF) requires a comprehensive management strategy that uses the full force of available data and technology, including anticoagulation, ablative therapy, and left atrial appendage occlusion. Patient-centered care with an emphasis on shared decision-making is particularly relevant to the authors' understanding of the complexity of AF and has helped them tailor therapy in this ever-growing patient population.

Stroke prevention in atrial fibrillation: An Asian perspective

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. In 2050, it is estimated that there will be 72 million AF patients in Asia, accounting for almost 2.9 million patients suffering from AF-associated stroke. Asian AF patients share similar risk factor profiles as non-Asians, except that more Asians have a history of previous stroke. Clinical challenges are evident in the field of stroke prevention in AF, amongst Asians. Existing stroke and bleeding risk scores have not been well-validated in Asians. Asians are prone to bleeding when treated with warfarin, and the optimal international normalised ratio (INR) for warfarin use is yet to be determined in Asians, though Asian physicians tend to keep it in a lower range (e.g. INR 1.6–2.6) for elderly patients despite limited evidence to justify this. In general, warfarin is ‘difficult’ to use in Asians due to higher risk of bleeding and higher stroke rate in Asians than in non-Asians, as shown in randomised controlled trials. Excess of bleeding was not found in Asians when novel oral anticoagulants (NOACs) were used. Besides, the superiority of NOACs to warfarin in reducing thromboembolism was maintained in Asians. Therefore NOACs are preferentially indicated in Asians in terms of both efficacy and safety. Also, some preliminary data suggest that Asian patients with AF might not be the same. Future prospective randomised trials are needed for the selection of NOACs according to different ethnic background.

Note: The review process for this manuscript was fully handled by Christian Weber, Editor in Chief.

Oral anticoagulation use by patients with atrial fibrillation in Germany

Atrial fibrillation (AF) is the most common significant cardiac rhythm disorder. Oral anticoagulation (OAC) is recommended by guidelines in the presence of a moderate to high risk of stroke. Based on an analysis of claims-based data, the aim of this contribution is to quantify the stroke-risk dependent OAC utilisation profile of German AF patients as well as the possible causes and the associated clinical outcomes of OAC under-use. Our data set was derived from two large mandatory German medical insurance funds. Risk stratification of patients was based on the CHADS2-score and the CHA2DS2-VASc-score. Two different scenarios were constructed to deal with factors potentially disfavouring OAC use. Causes of OAC under-use and its clinical consequences were analysed using multivariate analysis. Observation year was 2008. A total of 183,448 AF patients met the inclusion criteria. This represents an AF prevalence of 2.21%. The average CHADS2-score was 2.8 (CHA2DS2-VASc-score: 4.3). On between 40.5 and 48.7% of the observed patient-days, there was no antithrombotic protection by OAC, other anticoagulants or aspirin. Older female patients with a high number of comorbidities had a higher risk of OAC under-use. Patients who had already experienced a thromboembolic event had a lower risk of OAC under-use. In the observation year, 3,367 patients experienced a stroke (incidence rate 1.8%). In our multi-level Poisson random effects estimate, OAC use decreases the stroke rate by almost 80% (IRR 0.236). In conclusion, OAC under-use is widespread in the German market. It is associated with severe clinical consequences.

Stroke prevention in atrial fibrillation: Past, present and future

Concepts and our approaches to stroke prevention in atrial fibrillation (AF) have changed markedly over the last decade. There has been an evolution over the approach to stroke and bleeding risk assessment, as well as new treatment options. An increasing awareness of AF has led to calls to improve the detection of and population screening for AF. Stroke and bleeding risk assessment continues to evolve, and the ongoing debate on balance between simplicity and practicality, against precision medicine will continue. In this review article, we provide an overview of past, present and the (likely) future concepts and approaches to stroke prevention in AF. We propose three simple steps (the Birmingham ‘3-step’) that offers a practical management pathway to help streamline and simplify decision-making for stroke prevention in patients with AF.

Note: The review process for this paper was fully handled by Christian Weber, Editor in Chief.

Predicting in a predicament: Stroke and hemorrhage risk prediction in dialysis patients with atrial fibrillation

Whether to anticoagulate dialysis patients with atrial fibrillation is a common clinical dilemma with limited high-quality data to inform decision-making. While the efficacy and safety of anticoagulation for stroke prevention in dialysis patients with atrial fibrillation has long been debated and remains unclear, the more upstream issue of stroke risk assessment from atrial fibrillation has received relatively little attention. In the general population, a handful of risk scores to help predict stroke and hemorrhage risk in the setting of atrial fibrillation are widely validated and applied in clinical practice. But are they applicable to the dialysis population? The most commonly used stroke risk scores, CHADS2 and CHA2DS2-VASC, have limited validation in the dialysis population, and when validated, have shown poor performance (c-statistics <0.70). Stroke risk scores derived in the general atrial fibrillation population may perform poorly in dialysis patients for a number of reasons. Dialysis patients have unique stroke risk factors, such as chronic inflammation and vascular calcification, and a much higher competing risk of death, none of which are accounted for in current risk scores. Further complicating the dilemma of anticoagulation is hemorrhage risk, which is known to be exceedingly high in dialysis patients. Currently available hemorrhage risk scores, such as HAS-BLED, have not been validated in dialysis patients and will likely underestimate hemorrhage risk. Moving forward, risk tools specific to the dialysis population are needed to accurately assess and balance stroke and hemorrhage risks in dialysis patients with atrial fibrillation.

Incorporating Stroke and Bleeding Risk Stratification Tools into Atrial Fibrillation Management Making Sense of the Alphabet Soup

Atrial fibrillation (AF) is a common arrhythmia managed by many physicians in a variety of clinical settings. One of the most important clinical decisions related to effective AF management centers upon the need to perform accurate thromboembolic risk stratification followed by effective management decisions that align with established guidelines. This manuscript will review the present state of the art and provide guidance to physicians to enhance patient outcomes.

Risk Prediction for Ischemic Stroke and Transient Ischemic Attack in Patients Without Atrial Fibrillation: A Retrospective Cohort Study

BACKGROUND

Stroke mainly occurs in patients without atrial fibrillation (AF). This study explored risk prediction models for ischemic stroke and transient ischemic attack (TIA) in patients without AF.

METHODS

Three US-based healthcare databases (Truven MarketScan Commercial Claims and Encounters [CCAE], Medicare Supplemental [MDCR], and Optum Clinformatics [Optum]) were used to establish patient cohorts without AF during the index period of 2008-2012. The performance of 2 existing models (CHADS₂ and CHA₂DS₂-VASc) for predicting stroke and TIA was examined by fitting a logistic regression to a training dataset and evaluating predictive accuracy in a validation dataset (area under the curve, AUC) using patients with complete follow-up of 1 or 3 years, separately.

RESULTS

The commercial populations were younger and had fewer comorbidities than Medicare-eligible population. The incidence proportions of ischemic stroke and TIA during 1 and 3 years of follow-up were .5% and 1.9% (CCAE), .6% and 2.2% (Optum), and 4.6% and 13.1% (MDCR), respectively. The models performed consistently across all 3 databases, with the AUC ranging from .69 to .77 and from .68 to .73 for 1- and 3-year prediction, respectively. Predictive accuracy was lower than the initial work of CHADS₂ evaluation in patients with AF (AUC: .82), but consistent with a subsequent meta-analysis of CHADS₂ (.60-.80) and CHA₂DS₂-VASc performance (.64-.79).

CONCLUSION

Although the existing schemes for predicting ischemic stroke and TIA in patients with AF can be applied to patients without AF with comparable predictive accuracy, the evidence suggests that there is room for improvement in these models' performance.

Primary and key secondary results from the ROCKET AF trial, and their implications on clinical practice

BACKGROUND

The safety and efficacy of the oral anticoagulant rivaroxaban were studied in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF trial). A number of subanalyses of the ROCKET AF trial have subsequently analyzed the use of rivaroxaban in special patient populations.

METHODS

The outcomes of the ROCKET AF trial were reviewed. The use of rivaroxaban in higher risk populations, as determined by the presence of co-morbidities included in the CHADS2 criteria, was analyzed. Requirements for dose adjustment in patients with renal impairment and in East Asian patients were described. Finally, clinical management challenges, including interruptions in therapy, drug discontinuation, management of bleeding events, drug interactions, and management of patients requiring cardioversion/ablation were reviewed.

RESULTS

Rivaroxaban is efficacious in high-risk populations, including elderly patients, patients with diabetes, heart failure, history of stroke, prior myocardial infarction, or peripheral arterial disease (PAD). Patients with PAD have a higher risk of bleeding with rivaroxaban compared with warfarin. East Asian populations do not require a dose adjustment for rivaroxaban, while a reduced dose of 15 mg daily is required for patients with moderate renal impairment. Rivaroxaban remains effective with temporary interruptions in therapy and in patients requiring cardioversion/ablation. Rates of major bleeding and subsequent outcomes were similar in patients on warfarin and rivaroxaban, although rates of gastrointestinal bleeding were higher with rivaroxaban. Concurrent use of antiarrhythmic therapy was not associated with adverse outcomes.

CONCLUSIONS

Rivaroxaban represents an efficacious alternative to warfarin in high-risk patients with AF. Dose adjustment is required for patients with moderate renal impairment. Rivaroxaban can be used safely in a number of challenging clinical management scenarios although the concurrent use of amiodarone requires more study.

2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Both the incidence and prevalence of AF are increasing, and the burden of AF is becoming huge. Many innovative advances have emerged in the past decade for the diagnosis and management of AF, including a new scoring system for the prediction of stroke and bleeding events, the introduction of non-vitamin K antagonist oral anticoagulants and their special benefits in Asians, new rhythm- and rate-control concepts, optimal endpoints of rate control, upstream therapy, life-style modification to prevent AF recurrence, and new ablation techniques. The Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology aimed to update the information and have appointed a jointed writing committee for new AF guidelines. The writing committee members comprehensively reviewed and summarized the literature, and completed the 2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the Management of Atrial Fibrillation. This guideline presents the details of the updated recommendations, along with their background and rationale, focusing on data unique for Asians. The guidelines are not mandatory, and members of the writing committee fully realize that treatment of AF should be individualized. The physician's decision remains most important in AF management.

How well does physician risk assessment predict stroke and bleeding in atrial fibrillation? Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF)

BACKGROUND

Assessments of stroke and bleeding risks are essential to selecting oral anticoagulation in patients with atrial fibrillation (AF). We aimed to assess outcomes according to physician assessed risk, with comparison to empirical risk scores.

METHODS

This was a prospective, observational study of 9,715 outpatients with AF enrolled in ORBIT-AF, a US national registry. Stroke and bleeding risks were quantified by physician assignment, CHADS₂ and CHA₂DS₂-VASc stroke scores, and ATRIA and HAS-BLED bleeding scores. Outcomes were stroke or systemic embolism and major bleeding during a median follow-up of 28 months.

RESULTS

Physician-assigned risk was associated with thromboembolic events: low risk (0.71 per 100 patient-years [95% CI 0.56-0.91], n=3,991), intermediate risk (0.98 [95% CI 0.79-1.20], n=4,148), and high risk (1.84 [95% CI 1.43-2.37], n=1,576, P<.0001), and major bleeding: low (3.43 [95% CI 3.07-3.82], n=4,250), intermediate (4.55 [95% CI 4.03-5.15], n=2,702), and high (5.76 [95% CI 4.42-7.50], n=468; P<.0001). Discrimination of stroke risk was similar with CHADS₂ (c=0.59, 95% CI 0.57-0.61) vs physician assessment (c=0.58, 95% CI 0.55-0.62). Among patients on oral anticoagulation, bleeding risk discrimination was higher with ATRIA (c=0.63, 95% CI 0.61-0.65) and HAS-BLED (c=0.60, 95% CI 0.59-0.62) than with physician assessment (0.55, 95% CI 0.53-0.57). Physician-assessed risk categories did not add significantly to empirical risk scores, in Cox models for outcomes (P_adjusted>.05 for all physician assessments vs P_adjusted<.05 for empirical scores).

CONCLUSION

Physician-assigned risk showed a graded relationship with outcomes, and both physician-based and empirical scores yielded only moderate discrimination. Although empirical scores provided valuable risk stratification information (with or without physician judgment), physician assessment added little to existing scores. These data support the use of empirical scores for stroke and bleeding risk stratification, and the need for novel approaches to risk stratification in this population.

Anticoagulation Quality and Complications of using Vitamin K Antagonists in the Cardiac Surgery Outpatient Clinic

Introduction

In patients with mechanical prosthetic heart valves or atrial fibrillation requiring anticoagulation to prevent thromboembolic events, several factors influence adherence and anticoagulation complications.

Objective

To evaluate the factors that interfere with the quality and complications of anticoagulation with vitamin K antagonists.

Methods

A retrospective cohort study of 100 patients, in the period from 2011 to 2014, was performed. Anticoagulation conditions in the last year, regarding the presence of complications (embolisms/bleeding) and inadequate treatment were assessed: achievement of less than 8 annual prothrombin times and International Normalized Ratio outside therapeutic target in more than 40% of prothrombin times.

Results

There were 31 complications (22 minor bleeding without hospitalization and 9 major complications: 7 bleeding with hospitalization and two emboli); 70 were with International Normalized Ratio outside the target in more than 40% of the tests and 36 with insufficient number of prothrombin times. Socioeconomic factors, anticoagulant type and anticoagulation reason had no relationship with complications or with inadequate treatment. There were more complications in patients with longer duration of anticoagulation (P=0.001). Women had more International Normalized Ratio outside the target range (OR 2.61, CI:1.0-6.5; P=0.04). Patients with lower number of annual prothrombin times had longer times of anticoagulation (P=0.03), less annual consultations (P=0.02) and less dose adjustments (P=0.003). Patients with longer duration of anticoagulation have more complications (P=0.001).

Conclusion

There was a high rate of major complications and International Normalized Ratio was outside the goal. Less annual prothrombin times was related to longer duration of anticoagulation, less annual consultations and less dose adjustments. More major complications occurred in patients with longer duration of anticoagulation.

DOACs - advances and limitations in real world

The group of new oral anticoagulants or NOACs, now termed direct oral anticoagulants or DOACs, with their favourable results from large scale phase III clinical trials, represent a major advancement and expanded armamentarium in antithrombotic therapy. Dabigatran, rivaroxaban, apixaban and edoxaban are now in clinical routine use for prevention and treatment of arterial and venous thrombotic diseases as addressed in their clinical trials. Usage of the DOACs is expected to increase as clinicians gain more experience and reassurance with data from the real world studies which are generally consistent with that from clinical trials. Development of specific antidotes in management of bleeding complications and development of coagulation assays for their plasma levels will further boost the confidence in the DOACs. Nonetheless, there are still limitations associated with the DOACs. Many patients in need of anticoagulant therapy for indications not studied in the clinical trials will not be eligible for treatment with a DOAC. Conditions where more data is required include DOACs use in the paediatric age group, patients with atrial fibrillation and valvular heart disease, thrombosis associated with the anti-phospholipid syndrome and cancer associated thrombosis. The affordability and access to these drugs may pose an issue for many patients under healthcare systems not providing for these medications. With four new anticoagulants coming onboard very quickly, the focus has shifted to the practical approach and management in real life as many clinicians are not yet familiar with the DOACs. Clinicians need to be educated on how to manage this new class for drugs, from choosing the appropriate drug to prevention and managing bleeding complications as a lack of knowledge and understanding in these drugs will lead to inappropriate use and compromise on patient safety.

Are Existing Risk Scores for Nonvalvular Atrial Fibrillation Useful for Prediction or Risk Adjustment in Patients With Chronic Kidney Disease?

BACKGROUND

Comparative effectiveness studies are common in patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease (CKD), but the accuracy of current thromboembolic (n = 4) and bleeding (n = 3) prediction scores used for risk adjustment are uncertain in these patients because previous studies have included few CKD patients.

METHODS

This was a retrospective cohort study, using Cox models adjusted for time-varying coefficients, of nonanticoagulated adults with incident NVAF and kidney function (defined into Kidney Disease: Improving Global Outcomes [KDIGO] CKD categories) between 2002 and 2013.

RESULTS

Of 58,451 patients (mean age 66 years, 31.3% with CKD) followed for a median of 31 months, 21.3% died, 12.6% had a thromboembolic event (4.2 per 100 patient-years), and 7.8% had a major bleed (2.6 per 100 patient-years). There were graded associations between kidney function and all-cause mortality (adjusted hazard ratio [aHR], 1.88 [95% confidence interval (CI), 1.79-1.98] for very high vs low risk KDIGO category), major bleeding (aHR, 1.61 [95% CI, 1.47-1.76]), and thromboembolic events (aHR, 1.13 [95% CI, 1.04-1.23]). All 7 prediction scores had significantly poorer c statistics in patients with CKD: 0.50-0.59; all P < 0.0001 compared with those with normal kidney function (c statistics 0.69-0.70 for the 4 thromboembolic risk scores and 0.60-0.68 for the 3 bleeding risk scores). Inclusion of KDIGO category did not improve calibration or discrimination statistics for current prediction scores.

CONCLUSIONS

Existing NVAF risk scores exhibit poor discrimination in patients with CKD, limiting their utility for clinical decision-making or for risk adjustment in comparative effectiveness studies. Although CKD is an independent risk factor for adverse events, adding KDIGO class to current risk scores did not improve their performance.

Detection of Atrial Fibrillation Among Patients With Stroke Due to Large or Small Vessel Disease: A Meta-Analysis

BACKGROUND

Recent trials have demonstrated that extended cardiac monitoring increases the yield of paroxysmal atrial fibrillation (AF) detection in patients with cryptogenic stroke. The utility of extended cardiac monitoring is uncertain among patients with stroke caused by small and large vessel disease. We conducted a meta-analysis to estimate the yield of AF detection in this population.

METHODS AND RESULTS

We searched PubMed, Cochrane, and SCOPUS databases for studies on AF detection in stroke patients and excluded studies restricted to patients with cryptogenic stroke or transient ischemic attack. We abstracted AF detection rates for 3 populations grouped by stroke etiology: large vessel stroke, small vessel stroke, and stroke of undefined etiology (a mixture of cryptogenic, small vessel, large vessel, and other stroke etiologies). Our search yielded 30 studies (n=5687). AF detection rates were similar in patients with large vessel (2.2%, 95% CI 0.3-5.5; n=830) and small vessel stroke (2.4%, 95% CI 0.4-6.1; n=520). No studies had a monitoring duration longer than 7 days. The yield of AF detection in the undefined stroke population was higher (9.2%; 95% CI 7.1-11.5) compared to small vessel stroke (P=0.02) and large vessel stroke (P=0.02) populations.

CONCLUSIONS

AF detection rate is similar in patients with small and large vessel strokes (2.2-2.4%). Because no studies reported on extended monitoring (>7 days) in these stroke populations, we could not estimate the yield of AF detection with long-term cardiac monitoring. Randomized controlled trials are needed to examine the utility of AF detection with long-term cardiac monitoring (>7 days) in this patient population.

Predictive role of CHADS2 and CHA2DS2-VASc scores on stroke and thromboembolism in patients without atrial fibrillation: a meta-analysis

OBJECTIVE

CHA2DS2-VASc is the extension of the CHADS2 score developed by Birmingham 2009. This risk stratification schema is often used in clinical setting when considering additional risk factors for developing stroke in AF patients. However, its role in the non-AF population is unknown. This study was designed to evaluate the accuracy of the CHADS2 and the CHA2DS2-VASc scoring systems.

METHODS

Studies designed for CHADS2 and CHA2DS2-VASc score in stratifying the risks for stroke development in non-AF patients were included.

RESULTS

Among the 114 studies identified, six trials were chosen finally and included for meta-analysis. The pooled diagnostic odds ratio (DOR) for CHADS2 and CHA2DS2-VASc was 2.86 (95% CI =1.83-4.28) and 2.80 (95% CI =1.83-4.28), respectively. CHA2DS2-VASc score was of better sensitivity than CHADS2 score (0.920 vs. 0.768). However, both scores were showed to have inherent heterogeneity and poor specificity.

CONCLUSIONS

Though having good diagnostic accuracy, the clinical application of the CHADS2 and CHA2DS2-VASc scores in predicting risk of stroke development in non-AF patients still needs further validation. Key message The overall diagnostic accuracy of CHADS2 and CHA2DS2-VASc in stroke-risk stratification was good in patients with non-atrial fibrillation.

Stroke risk assessment in atrial fibrillation: risk factors and markers of atrial myopathy

Atrial fibrillation (AF) is a complex phenomenon associated with electrical, mechanical, and structural abnormalities of the atria. Ischaemic stroke in AF is only partially understood, but the mechanisms are known to be related to the atrial substrate as well as the atrial rhythm. The temporal dissociation between timing of AF and occurrence of stroke has led to the hypothesis that fibrotic, prothrombotic atrial tissue is an important cause of thrombus formation in patients with AF, independent of the atrial rhythm. Current stroke risk scores are practical, but limited in their capacity to predict stroke risk accurately in individual patients. Stroke prediction might be improved by the addition of emerging risk factors, many of which are expressions of atrial fibrosis. The use of novel parameters, including clinical criteria, biomarkers, and imaging data, might improve stroke risk prediction and inform on optimal treatment for patients with AF and perhaps individuals only at risk of AF.

Assessment and comparison of CHADS2, CHA2DS2-VASc, and HAS-BLED scores in patients with atrial fibrillation in Saudi Arabia

AIMS:

No previous reports on the utilization of CHADS2, CHA2DS2-VASc, and HAS-BLED scores in atrial fibrillation (AF) patients in Saudi Arabia have been identified in the literature. The main objectives of this study were to assess and compare the distribution of CHADS2, CHA2DS2-VASc, and HAS-BLED scores and to identify the most common risk factors for stroke and bleeding among AF patients attending clinical pharmacists managed anticoagulation clinic.

SETTINGS AND DESIGN:

This cross-sectional study was conducted over 2 months period at clinical pharmacists managed anticoagulation clinic.

METHODS:

CHADS2, CHA2DS2-VASc, and HAS-BLED scores were calculated and compared for all eligible patients.

RESULTS:

Two hundred and sixty-four patients with AF were included in the analysis. The number of patients at low risk for stroke was found to be 14 (5.3%) using CHADS2 and only 4 (1.5%) using CHA2DS2-VASc. On the other hand, 64 patients (24.2%) were found at moderate risk for stroke using CHADS2 compared with 17 patients (6.4%) using CHA2DS2-VASc. Most of the patients were found to be at high risk for stroke using either the CHADS2 (70.5%) and CHA2DS2-VASc (92%). The study also revealed that most of the patients were at moderate (63.3%) to high (27.7%) risk of bleeding.

CONCLUSIONS:

The results of this study show that the percentage of patients at high risk for stroke and bleeding is very high. The study revealed that this could be attributed to the high prevalence of modifiable risk factors for stroke and for bleeding in Saudi patients with AF.

Comparison of the ATRIA, CHADS2, and CHA2DS2-VASc stroke risk scores in predicting ischaemic stroke in a large Swedish cohort of patients with atrial fibrillation

AIMS

Better stroke risk prediction is needed to optimize the anticoagulation decision in atrial fibrillation (AF). The ATRIA stroke risk score (ATRIA) was developed and validated in two large California community AF cohorts. We compared the performance of the ATRIA, CHADS₂, and CHA₂DS₂-VASc scores in a national Swedish AF (SAF) cohort.

METHODS AND RESULTS

We examined all Swedish patients hospitalized, or visiting a hospital-based outpatient clinic, with a diagnosis of AF from July 2005 through December 2010. Variables were determined from comprehensive national databases. Risk scores were assessed via C-index (C) and net reclassification improvement (NRI). The cohort included 152 153 AF patients not receiving warfarin. Overall, 11 053 acute ischaemic strokes were observed with mean rate 3.2%/year, higher than the 2%/year in the California cohorts. Using entire point scores, ATRIA had a good C of 0.708 (0.704-0.713), significantly better than CHADS₂ 0.690 (0.685-0.695) or CHA₂DS₂-VASc 0.694 (0.690-0.700). Using published cut-points for low/moderate/high risk, C deteriorated but ATRIA remained superior. Net reclassification improvement favoured ATRIA 0.16 (0.14-0.17) vs. CHADS₂ and 0.21 (0.20-0.23) vs. CHA₂DS₂-VASc. Net reclassification improvement decreased when cut-points were altered to better fit the cohort's stroke rates.

CONCLUSION

In this SAF cohort, the ATRIA score predicted ischaemic stroke risk better than CHADS₂ or CHA₂DS₂-VASc. However, relative performance of the categorical scores varied by population stroke rates. Score cut-points may need to be optimized to better fit local population stroke rates.

Effectiveness, safety and costs of thromboembolic prevention in patients with non-valvular atrial fibrillation: phase I ESC-FA protocol study and baseline characteristics of a cohort from a primary care electronic database

PURPOSE

Atrial fibrillation is the most common arrhythmia. Its management aims to reduce symptoms and to prevent complications through rate and rhythm control, management of concomitant cardiac diseases and prevention of related complications, mainly stroke. The main objective of Effectiveness, Safety and Costs in Atrial Fibrillation (ESC-FA) study is to analyse the drugs used for the management of the disease in real-use conditions, particularly the antithrombotic agents for stroke prevention. The aim of this work is to present the study protocol of phase I of the ESC-FA study and the baseline characteristics of newly diagnosed patients with atrial fibrillation in Catalonia, Spain.

PARTICIPANTS

The data source is System for the Improvement of Research in Primary Care (SIDIAP) database. The population included are all patients with non-valvular atrial fibrillation diagnosis registered in the electronic health records during 2007-2012.

FINDINGS TO DATE

A total of 22,585 patients with non-valvular atrial fibrillation were included in the baseline description. Their mean age was 72.8 years and 51.6% were men. The most commonly prescribed antithrombotics were vitamin K antagonists (40.1% of patients) and platelet aggregation inhibitors (32.9%); 25.3% had not been prescribed antithrombotic treatment. Age, gender, comorbidities and co-medication at baseline were similar to those reported for previous studies.

FUTURE PLANS

The next phase in the ESC-FA study will involve assessing the effectiveness and safety of antithrombotic treatments, analysing stroke events and bleeding episodes' rates in our patients (rest of phase I), describing the current management of the disease and its costs in our setting, and assessing how the introduction of new oral anticoagulants changes the stroke prevention in non-valvular atrial fibrillation.

Stroke Risk Factors Beyond the CHA₂DS₂-VASc Score: Can We Improve Our Identification of "High Stroke Risk" Patients With Atrial Fibrillation?

The prevention of stroke and other thromboembolic events plays a crucial role in the management of patients with atrial fibrillation. Not all patients with atrial fibrillation are equal in terms of thromboembolic risk; therefore, not all will benefit from oral anticoagulation treatment. The general principle is that the expected benefit of anticoagulation in reduction of thromboembolic risk must exceed the expected harm caused by possible bleeding. Some guidelines have focused on a categorical approach to stroke prevention, with a focus on identifying patients at high risk for oral anticoagulation. Various current guidelines recommend assessment of stroke risk using the CHADS2 or CHA2DS2-VASc scores to initially detect patients at low risk who require no antithrombotic therapy. However, the scores do not incorporate all possible risk factors causing a high thromboembolic risk. Factors such as impaired renal function, obstructive sleep apnea, and echocardiographic and biochemical or coagulation parameters can also predict adverse thromboembolic events. The present review aims to describe biomarkers whether blood, urine, imaging (cardiac or cerebral), or clinical that go beyond the CHA2DS2-VASc score and potentially aid stroke risk assessment. Although useful in some cases, the presented parameters should be perhaps used to further refine initial identification of patients at low risk, after which effective stroke prevention can be offered to those with ≥1 additional stroke risk factors.

Validation of the Ability of SYNTAX and Clinical SYNTAX Scores to Predict Adverse Cardiovascular Events After Stent Implantation: A Systematic Review and Meta-Analysis

To compare the predicative ability of SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) and clinical SYNTAX scores for major adverse cardiac events (MACEs) after stent implantation in patients with coronary artery disease (CAD). Studies were identified by electronic and manual searches. Twenty-six studies were included in the meta-analysis. The pooled C-statistics of SYNTAX score for 1- and 5-year all-cause mortality (ACM) were 0.65 (95% confidence interval [CI]: 0.61-0.68) and 0.62 (95% CI: 0.59-0.65), respectively, with weak heterogeneity. The 1- and 5-year ACM pooled C-statistics for clinical SYNTAX scores were significantly higher at 0.77 and 0.71, respectively (Ps < .05). Both scoring systems predicted 1- and 5-year MACE equally well. The pooled risk ratio of the SYNTAX score for predicting 1-year ACM per unit was 1.04 (95% CI: 1.03-1.05). Calibration analysis indicated SYNTAX scores overestimated the risk of major adverse cardiac and cerebrovascular events in each risk stratum. The SYNTAX score demonstrated minimal discrimination in predicting 1- or 5-year adverse cardiovascular events after percutaneous coronary intervention in patients with CAD. The clinical SYNTAX score could further improve the predictive capability for ACM but not MACE.

The Indian consensus guidance on stroke prevention in atrial fibrillation: An emphasis on practical use of nonvitamin K oral anticoagulants

The last ten years have seen rapid strides in the evolution of nonvitamin K oral anticoagulants (NOACs) for stroke prevention in patients with atrial fibrillation (AF). For the preparation of this consensus, a comprehensive literature search was performed and data on available trials, subpopulation analyses, and case reports were analyzed. This Indian consensus document intends to provide guidance on selecting the right NOAC for the right patients by formulating expert opinions based on the available trials and Asian/Indian subpopulation analyses of these trials. A section has been dedicated to the current evidence of NOACs in the Asian population. Practical suggestions have been formulated in the following clinical situations: (i) Dose recommendations of the NOACs in different clinical scenarios; (ii) NOACs in patients with rheumatic heart disease (RHD); (iii) Monitoring anticoagulant effect of the NOACs; (iv) Overdose of NOACs; (v) Antidotes to NOACs; (vi) Treatment of hypertrophic cardiomyopathy (HCM) with AF using NOACs; (vii) NOACs dose in elderly, (viii) Switching between NOACs and vitamin K antagonists (VKA); (ix) Cardioversion or ablation in NOAC-treated patients; (x) Planned/emergency surgical interventions in patients currently on NOACs; (xi) Management of bleeding complications of NOACs; (xii) Management of acute coronary syndrome (ACS) in AF with NOACs; (xiii) Management of acute ischemic stroke while on NOACs.

Composite end point analyses of non-vitamin K antagonist oral anticoagulants compared with warfarin in patients with atrial fibrillation

OBJECTIVE

Non-vitamin K antagonist oral anticoagulants (NOACs) have been proposed as alternatives to vitamin K antagonists (VKAs). The aim of this study is to examine the efficacy and safety of NOACs compared with warfarin with composite end points in patients with atrial fibrillation.

METHODS

This semi-systematic review performed a study of Phase III randomized controlled trials comparing NOACs with vitamin K antagonists (VKAs) in patient with atrial fibrillation using composite end points (combination of various clinical events). The use of composite end points allowed for combining efficacy and safety outcomes, thereby comparing the differences between NOAC and warfarin therapy from a clinical perspective.

RESULTS

Treatment with NOAC compared with warfarin was associated with a significant reduction in the sum of stroke or non-CNS, systemic embolism and major bleeding (odds ratio 0.87; 95% CI: 0.82-0.91).

CONCLUSION

Generally, NOACs were associated with a more favorable efficacy and safety profile compared with warfarin with regard to composite end points.

Atrial ectopy predicts late recurrence of atrial fibrillation after pulmonary vein isolation

BACKGROUND

Late recurrence of atrial fibrillation (AF) after radiofrequency ablation remains significant. Asymptomatic recurrence poses a difficult clinical problem as it is associated with an equally increased risk of stroke and death compared with symptomatic AF events. Meta-analyses reveal that no single preablation patient characteristic efficiently predicts these AF recurrences. This study aimed to evaluate the prognostic value of premature atrial complex (PAC) occurrence with regard to the risk of late AF recurrence after radiofrequency ablation.

METHODS AND RESULTS

The study cohort consisted of 124 patients with 7-day Holter recordings at 6 months post radiofrequency ablation for AF. No patients had AF recurrence before this time. Patients were followed-up every 6 months. Holter-detected PACs were defined as any supraventricular complexes occurring >30% earlier than expected. During a median follow-up of 4.2 years (first quartile to third quartile [Q1-Q3]=1.6-4.5), 32 patients (26%) had late recurrences of AF at a median of 462 days (Q1-Q3=319-1026) post radiofrequency ablation. The number of PACs per 24 hours was 248 (Q1-Q3=62-1026) in patients with and 77 (Q1-Q3=24-448) in patients without recurrence of AF (P=0.02). Multivariate analysis of the risk of late AF recurrence found ≥142 PACs per 24 hours to have a hazard ratio 2.84 (confidence interval, 1.26-6.43), P=0.01.

CONCLUSIONS

This study showed that occurrence of ≥142 PACs per day at 6 months after PVI was independently associated with a significantly increased risk of late AF recurrence. These results could have important clinical implications for the design of post-PVI follow-up.

CLINICAL TRIAL REGISTRATION

URL: http://www.anzctr.org.au. Unique identifier: ACRTN12606000467538.

Stroke and bleeding risk in atrial fibrillation: navigating the alphabet soup of risk-score acronyms (CHADS2 , CHA2 DS2 -VASc, R2 CHADS2 , HAS-BLED, ATRIA, and more)

Stroke prevention is central to the management of patients with atrial fibrillation (AF). As effective stroke prophylaxis essentially requires oral anticoagulants, an understanding of the risks and benefits of oral anticoagulant therapy is needed. Although AF increases stroke risk 5-fold, this risk is not homogeneous. Many stroke risk factors also confer an increased risk of bleeding. Various stroke and bleeding risk-stratification schemes have been developed to help inform clinical decision-making. These scores were derived and validated in different study cohorts, ranging from highly selected clinical-trial cohorts to real-world populations. Thus, their performance and classification accuracy vary depending on their derivation cohort(s). In the present review, we provide an overview of currently available stroke and bleeding risk-stratification schemes. We particularly focus on the CHA2 DS2 -VASc and HAS-BLED schemes, as these are recommended by the latest European guidelines on AF management. Other risk-stratification schemes (eg, CHADS2 , R2 CHADS2 , ATRIA, HEMORR2 HAGES, QStroke) and their place in the decision-making are also considered.

Balancing bleeding and thrombotic risk with new oral anticoagulants in patients with atrial fibrillation

Atrial fibrillation (AF) markedly increases the risk of stroke. Warfarin is highly effective for the prevention of stroke in such patients, but it is difficult to use and causes bleeding. Three new oral anticoagulants have been approved for stroke prevention in AF patients, and are at least as effective as warfarin with better bleeding profiles. These new agents have changed and simplified our approach to stroke prevention, as the threshold for initiation of oral anticoagulation is lower. All patients with AF should be risk assessed using the CHA2DS2-VASc score, and all patients with a score of 1 or above (except women with female sex as their only risk factor on the CHA2DS2-VASc score) should be considered for oral anticoagulation with one of the new agents. Formal bleeding risk assessment is essential, and can be done by using the well-validated HAS-BLED score.

Prediction of stroke or TIA in patients without atrial fibrillation using CHADS2 and CHA2DS2-VASc scores

OBJECTIVES

To determine the accuracy of CHADS2 and CHA2DS2-VASc tools for predicting ischaemic stroke or transient ischaemic attack (TIA) and death in patients without a history of atrial fibrillation or flutter (AF).

METHODS

The study included 20 970 patients without known AF enrolled in the Alberta Provincial Project for Outcomes Assessment in Coronary Heart disease (APPROACH) prospective registry who were discharged after an acute coronary syndrome (ACS) between 2005 and 2011. The outcome measures were incident ischaemic stroke, TIA or death from any cause.

RESULTS

Over a median follow-up of 4.1 years, 453 patients (2.2%) had a stroke (n=297) or TIA (n=156) and 1903 (9.0%) died. The incidence of stroke or TIA increased with increases in each risk score (p<0.001), with an absolute annual incidence ≥1% with CHADS2 ≥3 or CHA2DS2-VASc ≥4. Both CHADS2 and CHA2DS2-VASc scores had acceptable discrimination performance (C-statistic=0.68 and 0.71, respectively). The mortality rate was also greater in patients with higher CHADS2 and CHA2DS2-VASc scores (p<0.0001).

CONCLUSIONS

In patients with ACS but no AF, the CHADS2 and CHA2DS2-VASc scores predict ischaemic stroke/TIA events with similar accuracy to that observed in historical populations with non-valvular AF, but with lower absolute event rates. Further study of the utility of the CHADS2 and CHA2DS2-VASc scores for the assessment of thromboembolic risk and selection of antithrombotic therapy in patients without AF is warranted.

Stroke And Bleeding Risk Assessment: Where Are We Now?

Atrial fibrillation (AF) is one of major problems of the contemporary cardiology. Ischaemic stroke is a common complication of the AF, and effective prophylaxis requires treatment with oral anticoagulants. The purpose of this current review article is to provide an overview of the various stroke and bleeding risk assessment scores that help decision making with respect to thromboprophylaxis. Particular focus is made on the currently guideline-recommended stroke and bleeding risk scores, such as CHA₂DS₂-VASc (congestive heart failure or left ventricular dysfunction, hypertension, age ≥75, diabetes, stroke, vascular disease, age 65-74 and sex category [female]) and HAS-BLED (uncontrolled hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly [e.g. age >65, frail condition], drugs [e.g. aspirin, nonsteroidal anti-inflammatory drugs]/excessive alcohol) is made. Future directions for improvement of predictive ability of risk assessment with clinical factors and biomarkers are also discussed.

Is bleeding a necessary evil? The inherent risk of antithrombotic pharmacotherapy used for stroke prevention in atrial fibrillation

Current European atrial fibrillation (AF) guidelines have assigned a strong recommendation for the initiation of antithrombotic therapy to prevent thromboembolism in all but those AF patients at low risk (or with contraindications). Furthermore, the selection of antithrombotic therapy is based on the absolute risks of thromboembolism and bleeding, and the relative risk and benefit for a given patient. By their very mechanism of action, antithrombotic agents used for stroke prevention in AF will potentially increase the risk of bleeding events. Moreover, the introduction of novel oral anticoagulation agents have introduced new, hitherto ill-defined, deficiencies in the authors' knowledge with respect to anticoagulation monitoring, availability of direct antidotes, drug-drug interactions and the ability to appropriately control and reverse their actions if bleeding events occur. The authors present a comprehensive review on all aspects of bleeding related to currently licensed antithrombotic agents used for stroke prevention in patients with AF.

Anticoagulation in atrial fibrillation

Atrial fibrillation increases the risk of stroke, which is a leading cause of death and disability worldwide. The use of oral anticoagulation in patients with atrial fibrillation at moderate or high risk of stroke, estimated by established criteria, improves outcomes. However, to ensure that the benefits exceed the risks of bleeding, appropriate patient selection is essential. Vitamin K antagonism has been the mainstay of treatment; however, newer drugs with novel mechanisms are also available. These novel oral anticoagulants (direct thrombin inhibitors and factor Xa inhibitors) obviate many of warfarin's shortcomings, and they have demonstrated safety and efficacy in large randomized trials of patients with non-valvular atrial fibrillation. However, the management of patients taking warfarin or novel agents remains a clinical challenge. There are several important considerations when selecting anticoagulant therapy for patients with atrial fibrillation. This review will discuss the rationale for anticoagulation in patients with atrial fibrillation; risk stratification for treatment; available agents; the appropriate implementation of these agents; and additional, specific clinical considerations for treatment.

Lack of concordance between empirical scores and physician assessments of stroke and bleeding risk in atrial fibrillation: results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry

BACKGROUND

Physicians treating patients with atrial fibrillation (AF) must weigh the benefits of anticoagulation in preventing stroke versus the risk of bleeding. Although empirical models have been developed to predict such risks, the degree to which these coincide with clinicians' estimates is unclear.

METHODS AND RESULTS

We examined 10 094 AF patients enrolled in the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF) registry between June 2010 and August 2011. Empirical stroke and bleeding risks were assessed by using the congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and previous stroke or transient ischemic attack (CHADS2) and Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) scores, respectively. Separately, physicians were asked to categorize their patients' stroke and bleeding risks: low risk (<3%); intermediate risk (3%-6%); and high risk (>6%). Overall, 72% (n=7251) in ORBIT-AF had high-risk CHADS2 scores (≥2). However, only 16% were assessed as high stroke risk by physicians. Although 17% (n=1749) had high ATRIA bleeding risk (score ≥5), only 7% (n=719) were considered so by physicians. The associations between empirical and physician-estimated stroke and bleeding risks were low (weighted Kappa 0.1 and 0.11, respectively). Physicians weighed hypertension, heart failure, and diabetes mellitus less significantly than empirical models in estimating stroke risk; physicians weighted anemia and dialysis less significantly than empirical models when estimating bleeding risks. Anticoagulation use was highest among patients with high stroke risk, assessed by either empirical model or physician estimates. In contrast, physician and empirical estimates of bleeding had limited impact on treatment choice.

CONCLUSIONS

There is little agreement between provider-assessed risk and empirical scores in AF. These differences may explain, in part, the current divergence of anticoagulation treatment decisions from guideline recommendations.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01165710.

Mechanisms of Stroke in Atrial Fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia and is associated with a high risk of stroke and thromboembolism. Increasing evidence suggests that the thrombogenic tendency inherent to atrial fibrillation is related to several underlying pathophysiological mechanisms, including reduced flow in the left atrium, changes in vessel walls, and changes in blood constituents. This article reviews the mechanisms of stroke, available risk stratification tools and therapies available for prevention of stroke in patients with atrial fibrillation.

Usefulness of N-terminal pro-B-type natriuretic Peptide levels for stroke risk prediction in anticoagulated patients with atrial fibrillation

BACKGROUND AND PURPOSE

Oral anticoagulation is highly effective in reducing stroke and mortality in atrial fibrillation (AF). Several risk stratification schemes have been developed using clinical characteristics. Elevated levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) are important markers of increased mortality and morbidity in congestive heart failure and general community population. The aim of our study was to assess the predictive value of NT-proBNP levels in an unselected real-world cohort of anticoagulated patients with AF.

METHODS

We studied 1172 patients (49% male; median age, 76 years) with permanent AF who were well stabilized on oral anticoagulation (international normalized ratio, 2.0-3.0). Plasma NT-proBNP levels were quantified at baseline. We recorded thrombotic and vascular events, mortality, and major bleeding. The best cutoff points were assessed by receiver-operating characteristic curves.

RESULTS

Median levels (interquartile range) of NT-proBNP were 610 (318-1037) pg/mL. Median follow-up was 1007 (806-1279) days. On multivariate analysis, high NT-proBNP was significantly associated with the risk of stroke (hazards ratio, 2.71; P=0.001) and composite vascular events (acute coronary syndrome or acute heart failure; hazards ratio, 1.85; P=0.016), as well as a significant association with mortality (adjusted hazards ratio, 1.66; P=0.006). No association with bleeding was found (P=0.637). The integrated discrimination improvement (IDI) analysis demonstrated that NT-proBNP improved the Congestive heart failure, Hypertension, Age≥75 (doubled), Diabetes mellitus, Stroke (doubled)-Vascular disease and Sex category (female); CHA2DS2-VASc score for predicting embolic events (relative IDI, 2.8%; P=0.001) and all-cause death (relative IDI, 1.8%; P=0.001).

CONCLUSIONS

In real-world cohort of anticoagulated patients with AF, NT-proBNP provided complementary prognostic information to an established clinical risk score (CHA2DS2-VASc) for the prediction of stroke/systemic embolism. NT-proBNP was also predictive of all-cause mortality, suggesting that this biomarker may potentially be used to refine clinical risk stratification in anticoagulated patients with AF.