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A letter to the editor is presented in response to the article "Wide variation in reported rates of stroke across cohorts of patients with atrial fibrillation" by G. R. Quinn and colleagues that was published in the previous issue.

The article discusses the risk factor of stroke in patient with atrial fibrillation (AF). It examines the efficacy of oral anticoagulation (AOC) treatment in reducing stroke and mortality. It mentions that the risk of stroke in AF is not homogenous and varies with age and concomitant comorbidities. It notes the comparison of stroke risk stratification schemes.

The article discusses how to manage occult atrial fibrillation (AF)diagnosed on long-term monitoring. Topics include understanding the relationship between occult AF and thromboembolism, the use of observational studies and clinical trials to guide the management of occult AF, and stroke prevention in the presence of risk factors which is oral anticoagulants (OAC) with a vitamin K antagonist.

The article focuses on the use CHA2D2VASc and HAS-BLED scores for assessment of thromboprophylaxis in nonvalvular atrial fibrillation (AF). It states that the use of the CHA2D2VASc includes stroke risk factors and HAS-BLED assess bleeding risk. It says that the score systems must be used to ensure the identification of risks.

A response from the authors of the article "Should Patients With Atrial Fibrillation and 1 Stroke Risk Factor (CHA2DS2-VASc Score 1 in Men, 2 in Women) Be Anticoagulated? Yes: Even 1 Stroke Risk Factor Confers a Real Risk of Stroke" in the 2016;133 issue, is presented.

Background: Time in therapeutic range (TTR) is an important predictor of risk of thromboembolic (TE) and bleeding events in patients on vitamin K antagonists. This subgroup analysis of the RE-DUAL PCI trial assessed the safety and efficacy of dabigatran dual therapy compared with the warfarin triple therapy subgroup with high TTR (≥ overall median TTR). Methods: The RE-DUAL PCI trial randomized 2725 patients with atrial fibrillation (AF) who had undergone percutaneous coronary intervention (PCI) to warfarin triple therapy with clopidogrel or ticagrelor, and aspirin for 1-3 months, or to dabigatran dual therapy (110 or 150 mg bid) with clopidogrel or ticagrelor. This analysis categorized warfarin triple therapy group patients according to their TTR being < or ≥ the overall median TTR using the Rosendaal method and considering INR values measured later than 30 days after randomization. The ISTH major bleeding events (MBE) or clinically relevant non-major bleeding events (CRNMBE) and a composite thrombotic end point of death, myocardial infarction, stroke/systemic embolism, or unplanned revascularization, were compared with the warfarin triple therapy group with TTR ≥ overall median TTR. Results: At baseline, no clinically relevant differences were observed between comparator groups for age, CHA2DS2-VASc/HAS-BLED scores and creatinine clearance. Overall median TTR was 63.8% and 64.7% in the warfarin triple therapy comparator groups for dabigatran 110 and 150 dual therapy groups, respectively. Dabigatran dual therapy at both the doses had reduced rates of ISTH MBE and CRNMBE versus warfarin triple therapy (Figure). Conclusion: In AF patients after PCI, both doses of dabigatran dual therapy were associated with reduced risks of ISTH MBE or CRNMBE and had similar efficacy when compared with the warfarin triple therapy subgroup with high TTR. [ABSTRACT FROM AUTHOR]

A response from the author of the article "How to Manage Occult Atrial Fibrillation Detected on Long-Term Monitoring" published in a 2016 issue is presented.

Despite the many advances in cardiovascular medicine, decisions concerning the diagnosis, prevention, and treatment of left ventricular (LV) thrombus often remain challenging. There are only limited organizational guideline recommendations with regard to LV thrombus. Furthermore, management issues in current practice are increasingly complex, including concerns about adding oral anticoagulant therapy to dual antiplatelet therapy, the availability of direct oral anticoagulants as a potential alternative option to traditional vitamin K antagonists, and the use of diagnostic modalities such as cardiac magnetic resonance imaging, which has greater sensitivity for LV thrombus detection than echocardiography. Therefore, this American Heart Association scientific statement was commissioned with the goals of addressing 8 key clinical management questions related to LV thrombus, including the prevention and treatment after myocardial infarction, prevention and treatment in dilated cardiomyopathy, management of mural (laminated) thrombus, imaging of LV thrombus, direct oral anticoagulants as an alternative to warfarin, treatments other than oral anticoagulants for LV thrombus (eg, dual antiplatelet therapy, fibrinolysis, surgical excision), and the approach to persistent LV thrombus despite anticoagulation therapy. Practical management suggestions in the form of text, tables, and flow diagrams based on careful and critical review of actual study data as formulated by this multidisciplinary writing committee are given.

Growing evidence suggests a consistent association between atrial fibrillation (AF) and cognitive impairment and dementia that is independent of clinical stroke. This report from the AF-SCREEN International Collaboration summarizes the evidence linking AF to cognitive impairment and dementia. It provides guidance on the investigation and management of dementia in patients with AF on the basis of best available evidence. The document also addresses suspected pathophysiologic mechanisms and identifies knowledge gaps for future research. Whereas AF and dementia share numerous risk factors, the association appears to be independent of these variables. Nevertheless, the evidence remains inconclusive regarding a direct causal effect. Several pathophysiologic mechanisms have been proposed, some of which are potentially amenable to early intervention, including cerebral microinfarction, AF-related cerebral hypoperfusion, inflammation, microhemorrhage, brain atrophy, and systemic atherosclerotic vascular disease. The mitigating role of oral anticoagulation in specific subgroups (eg, low stroke risk, short duration or silent AF, after successful AF ablation, or atrial cardiopathy) and the effect of rhythm versus rate control strategies remain unknown. Likewise, screening for AF (in cognitively normal or cognitively impaired patients) and screening for cognitive impairment in patients with AF are debated. The pathophysiology of dementia and therapeutic strategies to reduce cognitive impairment warrant further investigation in individuals with AF. Cognition should be evaluated in future AF studies and integrated with patient-specific outcome priorities and patient preferences. Further large-scale prospective studies and randomized trials are needed to establish whether AF is a risk factor for cognitive impairment, to investigate strategies to prevent dementia, and to determine whether screening for unknown AF followed by targeted therapy might prevent or reduce cognitive impairment and dementia.

Cardiac thromboembolism attributed to atrial fibrillation (AF) is responsible for up to one-third of ischemic strokes. Stroke may be the first manifestation of previously undetected AF. Given the efficacy of oral anticoagulants in preventing AF-related ischemic strokes, strategies of searching for AF after a stroke using ECG monitoring followed by oral anticoagulation (OAC) treatment have been proposed to prevent recurrent cardioembolic strokes. This white paper by experts from the AF-SCREEN International Collaboration summarizes existing evidence and knowledge gaps on searching for AF after a stroke by using ECG monitoring. New AF can be detected by routine plus intensive ECG monitoring in approximately one-quarter of patients with ischemic stroke. It may be causal, a bystander, or neurogenically induced by the stroke. AF after a stroke is a risk factor for thromboembolism and a strong marker for atrial myopathy. After acute ischemic stroke, patients should undergo 72 hours of electrocardiographic monitoring to detect AF. The diagnosis requires an ECG of sufficient quality for confirmation by a health professional with ECG rhythm expertise. AF detection rate is a function of monitoring duration and quality of analysis, AF episode definition, interval from stroke to monitoring commencement, and patient characteristics including old age, certain ECG alterations, and stroke type. Markers of atrial myopathy (eg, imaging, atrial ectopy, natriuretic peptides) may increase AF yield from monitoring and could be used to guide patient selection for more intensive/prolonged poststroke ECG monitoring. Atrial myopathy without detected AF is not currently sufficient to initiate OAC. The concept of embolic stroke of unknown source is not proven to identify patients who have had a stroke benefitting from empiric OAC treatment. However, some embolic stroke of unknown source subgroups (eg, advanced age, atrial enlargement) might benefit more from non-vitamin K-dependent OAC therapy than aspirin. Fulfilling embolic stroke of unknown source criteria is an indication neither for empiric non-vitamin K-dependent OAC treatment nor for withholding prolonged ECG monitoring for AF. Clinically diagnosed AF after a stroke or a transient ischemic attack is associated with significantly increased risk of recurrent stroke or systemic embolism, in particular, with additional stroke risk factors, and requires OAC rather than antiplatelet therapy. The minimum subclinical AF duration required on ECG monitoring poststroke/transient ischemic attack to recommend OAC therapy is debated.

Background: Stroke prevention with oral anticoagulants (OACs) is the cornerstone for the management of atrial fibrillation (AF). However, data about the use of OACs among patients ≥90 years of age are limited. We aimed to investigate the risk of ischemic stroke and intracranial hemorrhage (ICH) and the net clinical benefit of OAC treatment for very elderly patients with AF (≥90 years of age)., Methods: This study used the National Health Insurance Research Database in Taiwan. Risks of ischemic stroke and ICH were compared between 11 064 and 14 658 patients with and without AF ≥90 years of age without antithrombotic therapy from 1996 to 2011. Patients with AF (n=15 756) were divided into 3 groups (no treatment, antiplatelet agents, and warfarin), and the risks of stroke and ICH were analyzed. The risks of ischemic stroke and ICH were further compared between patients treated with warfarin and nonvitamin K antagonist OACs (NOACs) from 2012 to 2015 when NOACs were available in Taiwan., Results: Compared with patients without AF, patients with AF had an increased risk of ischemic stroke (event number/patient number, incidence = 742/11 064, 5.75%/y versus 1399/14 658, 3.00%/y; hazard ratio, 1.93; 95% confidence interval, 1.74-2.14) and similar risk of ICH (131/11 064, 0.97%/y versus 206/14 658, 0.54%/y; hazard ratio, 0.85; 95% confidence interval, 0.66-1.09) in competing risk analysis for mortality. Among patients with AF, warfarin use was associated with a lower stroke risk (39/617, 3.83%/y versus 742/11 064, 5.75%/y; hazard ratio, 0.69; 95% confidence interval, 0.49-0.96 in a competing risk model), with no difference in ICH risk compared with nontreatment. When compared with no antithrombotic therapy or antiplatelet drugs, warfarin was associated with a positive net clinical benefit. These findings persisted in propensity-matched analyses. Compared with warfarin, NOACs were associated with a lower risk of ICH (4/978, 0.42%/y versus 19/768, 1.63%/y; hazard ratio, 0.32; 95% confidence interval, 0.10-0.97 in a competing risk model), with no difference in risk of ischemic stroke., Conclusions: Among patients with AF ≥90 years of age, warfarin was associated with a lower risk of ischemic stroke and positive net clinical benefit. Compared with warfarin, NOACs were associated with a lower risk of ICH. Thus, OACs may still be considered as thromboprophylaxis for elderly patients, with NOACs being the more favorable choice., (© 2018 American Heart Association, Inc.)

Background: Stroke risk in atrial fibrillation is assessed by using the CHA 2 DS 2 -VASc score. Sex category (Sc, ie, female sex) confers 1 point on CHA 2 DS 2 -VASc. We hypothesized that female sex is a stroke risk modifier, rather than an overall risk factor, when added to a CHA 2 DS 2 -VA (sex-independent thromboembolism risk) score scale., Methods: Using 3 nationwide registries, we identified patients with incident nonvalvular atrial fibrillation from January 1, 1997, through December 31, 2015. Patients receiving oral anticoagulant treatment at baseline were excluded, and person-time was censored at the time of treatment initiation (if any). CHA 2 DS 2 -VA scores were calculated for men and women, and were followed for up to 1 year in the Danish National Patient Registry. The primary outcome was a primary hospital code for ischemic stroke or systemic embolism (thromboembolism). We calculated crude event rates for risk strata as events per 100 person-years. For quantifying absolute risk of stroke, we calculated risks based on the pseudovalue method. Female sex as a prognostic factor was investigated by inclusion as an interaction term on the CHA 2 DS 2 -VA score to calculate the thromboembolic risk ratio for different score points., Results: A total of 239 671 patients with atrial fibrillation (48.7% women) contributed to the analyses. The mean ages for women and men were 76.6 years and 70.3 years, respectively; the mean CHA 2 DS 2 -VA scores were 2.7 for women and 2.3 for men. The overall 1-year thromboembolic rate per 100 person-years for women was 7.3 and 5.7 for men. The 1-year absolute risk of thromboembolism was 0.5% among men and women with a CHA 2 DS 2 -VA score of 0 and increased up to >7% among very comorbid patients (score >5). The risk ratio (male as reference) across points >1 indicated that women exhibit a higher stroke risk. The interaction was statistically significant ( P <0.001)., Conclusions: Female sex is a risk modifier for stroke in patients with atrial fibrillation. Initial decisions on oral anticoagulant treatment could be guided by a CHA 2 DS 2 -VA score (ie, excluding the sex category criterion), but the Sc risk component modifies and accentuates stroke risk in women who would have been eligible for oral anticoagulant treatment on the basis of ≥2 additional stroke risk factors., (© 2018 American Heart Association, Inc.)