Focused 2012 Update of the Canadian Cardiovascular Society Atrial Fibrillation Guidelines: Recommendations for Stroke Prevention and Rate/Rhythm Control

The 2012 Canadian Cardiovascular Society heart failure management guidelines update: focus on acute and chronic heart failure

The 2012 Canadian Cardiovascular Society Heart Failure (HF) Guidelines Update provides management recommendations for acute and chronic HF. In 2006, the Canadian Cardiovascular Society HF Guidelines committee first published an overview of HF management. Since then, significant additions to and changes in many of these recommendations have become apparent. With this in mind and in response to stakeholder feedback, the Guidelines Committee in 2012 has updated the overview of both acute and chronic heart failure diagnosis and management. The 2012 Update also includes recommendations, values and preferences, and practical tips to assist the medical practitioner manage their patients with HF.

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.

A review of the epidemiological profile of patients with atrial fibrillation and heart failure

Heart failure (HF) and atrial fibrillation (AF) are cardiovascular diseases that have a continuously increasing prevelance and both often coexist. The presence of AF in HF patients has been reported as being between 10 and 50% depending on the different study settings. AF patients have a different clinical profile: they are older, with more severe HF and comorbidities than those without AF. Despite this poor clinical profile, observational studies report a lower use of the recommended treatments such as angiotensin-converting enzyme inhibitors and β-blockers. Clinical trials using antiarrhythmic drugs for rhythm control have failed to demonstrate the clinical advantage of a rhythm control approach over one for rate control. The prognostic role of AF in HF remains controversial, while the impact of new AF has been shown to be associated with an adverse outcome.

Female sex as a risk factor for stroke in atrial fibrillation: a nationwide cohort study

BACKGROUND

Female sex has been suggested as a risk factor for stroke/thromboembolism in patients with non-valvular atrial fibrillation (AF) and has therefore been included within risk scores, e.g., the CHA2 DS2 -VASc score, and guidelines.

OBJECTIVES

To investigate the risk of stroke/thromboembolism associated with female sex in non-valvular AF patients.

PATIENTS/METHODS

Using the national Danish registers, we identified non-anticoagulated patients discharged with non-valvular AF (1997-2008), and subdivided the population into three age intervals: < 65, 65-74 and ≥ 75 years. We calculated stroke rates according to sex, and assessed the stroke risk associated with female sex by using Cox regression analysis.

RESULTS

We included 87,202 AF patients, and 44,744 (51.3%) were female. The rate of stroke/thromboembolism for females aged < 65 and 65-74 years was not increased as compared with men, whereas the rate for females aged ≥ 75 years was increased. At both 1-year and 12-year follow-up, female sex did not increase the risk of stroke for patients aged < 75 years. At 1-year follow-up, the hazard ratios associated with female sex were 0.89 (95% confidence interval [CI] 0.70-1.13) and 0.91 (95 CI 0.79-1.05) for patients aged < 65 and 65-74 years, respectively, and being female and aged ≥ 75 years was associated with an increased risk of stroke of 1.20 (95 CI 1.12-1.28).

CONCLUSION

Female sex was only associated with an increased risk of stroke for AF patients aged ≥ 75 years. Our study suggests that female sex should not be automatically included as an independent stroke/thromboembolic risk factor in guidelines or in the CHA2 DS2 -VASc score, without careful prior consideration of the 'age < 65 and lone AF' criterion.

Novel oral anticoagulants for stroke prevention in atrial fibrillation: focus on apixaban

Stroke prevention in atrial fibrillation (AF) has been challenging over decades, mostly due to a number of difficulties associated with oral vitamin K antagonists (VKAs), which have been the most effective stroke prevention treatment for a long time. The oral direct thrombin inhibitors (e.g., dabigatran) and oral direct inhibitors of factor Xa (e.g., rivaroxaban, apixaban) have emerged recently as an alternative to VKAs for stroke prevention in AF. These drugs act rapidly, and have a predictable and stable dose-related anticoagulant effect with a few clinically relevant drug-drug interactions. The novel oral anticoagulants are used in fixed doses with no need for regular laboratory monitoring of anticoagulation intensity. However, each of these drugs has distinct pharmacological properties that could influence optimal use in clinical practice. The following phase 3 randomized trials with novel oral anticoagulants versus warfarin for stroke prevention in AF have been completed: the Randomized Evaluation of Long-term Anticoagulant therapy (RE-LY) trial with dabigatran, 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 with rivaroxaban, and the Apixaban for Reduction of Stroke and Other Thromboembolism Events in Atrial Fibrillation (ARISTOTLE) trial with apixaban. Moreover, the Apixaban Versus Acetylsalicylic Acid to prevent Strokes (AVERROES) trial included patients with AF who have failed or were unsuitable for warfarin, and compared apixaban versus aspirin for stroke prevention in AF. Overall, apixaban has two large trials for stroke prevention in AF showing benefits not only over warfarin, but also over aspirin among those patients who have failed or refused warfarin. In the ARISTOTLE trial, apixaban was superior to warfarin in the reduction of stroke or systemic embolism, major bleeding, intracranial hemorrhage, and all-cause mortality, with a similar reduction in the rate of ischemic stroke and better tolerability. When compared with aspirin in the AVERROES trial, apixaban was associated with more effective reduction of stroke, a similar risk of major bleeding, and better tolerability. In this review article, the authors summarize the current knowledge on novel oral anticoagulants and discuss the clinical aspects of their use for stroke prevention in AF, with particular emphasis on apixaban.