Antithrombotic therapy for atrial fibrillation: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Hospitalization for vitamin-K-antagonist-related bleeding: treatment patterns and outcome

BACKGROUND

Bleeding complications are common side effects of vitamin-K antagonist (VKA) therapy. Data on the in-hospital management and outcomes of these bleeding events are scarce and information is mostly derived from trial cohorts.

OBJECTIVES

The objective was to collect data on the management and clinical outcome of hospitalizations owing to VKA-related bleeding in real-world practice.

PATIENTS AND METHODS

We performed a multicenter observational cohort study involving 21 secondary and tertiary care hospitals in the administrative district Dresden, Saxony, Germany throughout the year 2005. All consenting patients presenting with VKA-related bleeding complications were included. No exclusion criteria applied. Data were collected at admission, at discharge and at 90 days to evaluate resource consumption, length of hospital stay and risk factors for in-hospital- and 3-month mortality.

RESULTS

Two hundred and ninety patients were included (median age 74 years; 50.7% male). The main indications for VKA therapy were atrial fibrillation (63.4%), prior thromboembolism (18.6%) and mechanical heart valves (11.4%), and most common bleeding localizations were large hematoma (23.1%), upper gastrointestinal (GI) tract (17.9%) and intracranial bleeding (14.1%). On hospital admission, the median International Normalized Ratio (INR) was 3.0 (range 0.9-12.5, interquartile range [IQR] 2.1-3.9). In-hospital mortality was 7.6% with impaired renal function as the most relevant risk factor. At 90 days mortality was 14.1% and 15.3% of survivors were help-dependent.

CONCLUSIONS

VKA-related bleeding leading to hospitalization is associated with long hospitalization, relevant resource utilization, high mortality or persistent sequlae. Patient-related factors such as impaired renal function, chronic cardiac or pulmonary disease and dementia are predictive of in-hospital and 3-month mortality.

New oral anticoagulants in elderly patients with atrial fibrillation

The prevalence of atrial fibrillation increases with age, augmenting the risk of embolic stroke in elderly individuals. Clinical practice guidelines recommend the long-term use of oral anticoagulation in elderly patients with atrial fibrillation to reduce risk of stroke. Until recently, vitamin K antagonists (eg, warfarin) were the only oral anticoagulants available, but using warfarin in elderly patients can be challenging. Newer oral anticoagulants may offer specific benefits and increased convenience for elderly patients, because they have predictable pharmacologic profiles, a rapid onset of action, a wide therapeutic window, no requirement for routine coagulation monitoring, and fewer and better-defined food and drug interactions compared with warfarin. This review highlights the benefits and challenges of warfarin use in elderly patients with atrial fibrillation and discusses potential efficacy and safety benefits for newer oral agents in these patients. The potential for increased rates of major bleeding in the elderly, particularly those with numerous concomitant medications or renal impairment, also is discussed. Practical considerations for the use of long-term anticoagulation in elderly patients also are discussed.

Recent Atrial Fibrillation Guidelines - Looking at Both Sides of the Atlantic

The American College of Cardiology (ACC), the American Heart Association (AHA) and the European Society of Cardiology (ESC) reported joint guidelines on atrial fibrillation (AF) in 2001 and a revised version in 2006. In 2010 new guidelines on AF were published by the ESC, and in 2011 by the American College of Cardiology Foundation (ACCF)/AHA/Heart Rhythm Society (HRS) and by the Canadian Cardiac Society (CCS). Focused updates have also appeared more recently. We reviewed these three sets of AF guidelines and compared their rating systems and their recommendations regarding four major AF management aspects (i.e. long-term rate control strategy, long-term rhythm control strategy, oral anticoagulation and AF catheter ablation). Significant differences were found between guidelines in the quality of evidence or level of evidence and on the strength of recommendations. Use of new anticoagulants and of new antiarrhythmic drug therapy is also discussed in the light of recent trial results. Whether multiplication of guidelines and differences in recommendation impact their implementation in clinical practice, remains to be assessed.

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.

Novel oral anticoagulants for stroke prevention in atrial fibrillation: a focus on the older patient

Atrial fibrillation (AF) is a common arrhythmia that is associated with an increased risk of stroke, particularly in the elderly. Traditionally, a vitamin K antagonist such as warfarin is prescribed for stroke prevention. Warfarin is effective at lowering stroke risk but has several limitations due to food restrictions, drug interactions, and a narrow therapeutic window. Various novel oral anticoagulants (NOACs) are available or under development to provide alternative treatment options. This article reviews the efficacy and safety of three NOACs (dabigatran etexilate, rivaroxaban, and apixaban) in addition to warfarin and aspirin, for prevention of stroke in patients with AF, focusing on the elderly population. Results of clinical trials demonstrate that the efficacy of NOACs for stroke prevention in patients with AF is as good as or better than that of warfarin. The NOACs are also associated with an equivalent or lower risk of bleeding. Regardless of the medication chosen, older patients with AF must be treated cautiously due to an increased risk of stroke and bleeding, as well as potential challenges related to drug interactions and monitoring requirements. NOACs may be suitable alternatives to warfarin for stroke prevention in older patients due to several advantages, including a faster onset of action, few drug or food interactions, and no requirement for regular monitoring. However, dose adjustments may be required for certain patients, such as those with severe renal impairment or in the setting of drug interactions.

Direct thrombin and factor Xa inhibition for stroke prevention in patients with atrial fibrillation

Nonvalvular atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia occurring in patients in the United States. The primary clinical consequence of AF is an increase in the risk and severity of strokes. Treatment guidelines recommend anticoagulation therapy for most patients with AF. One risk-stratification scheme, the CHADS2 index, is simple and widely used to determine the management of patients with AF in regard to stroke prevention. However, new schemes, such as CHA2DS2-VASc, further refine risk stratification to identify patients who would obtain a net clinical benefit from a particular management strategy, thus improving the quality of management. For patients with AF for whom oral anticoagulation (OAC) is advisable, vitamin K antagonist (VKA) therapy is well established and effective. However, OAC with VKAs presents challenges to prescribers and patients in maintaining therapeutic efficacy. Novel OACs may offer alternatives to VKAs. Dabigatran etexilate, a direct thrombin inhibitor, was approved by the US Food and Drug Administration (FDA) in 2010 for reducing the risk of stroke and systemic embolism in patients with nonvalvular AF. The activated factor X (factor Xa) inhibitor rivaroxaban was recently approved by the FDA both for prophylaxis of deep vein thrombosis, which may lead to pulmonary embolism in patients undergoing knee or hip arthroplasty, and for reducing the risk of stroke and systemic embolism in patients with nonvalvular AF. Apixaban, another factor Xa inhibitor, was recently shown to be effective for stroke prevention in patients with nonvalvular AF. This article reviews clinical considerations regarding new agents that may offer alternatives to VKA therapy for the prevention of stroke in patients with AF.

Recent advances in antithrombotic therapy for stroke prevention in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac dysrhythmia and patients with AF have a higher risk for stroke than the general population. The prevalence of AF is increasing, which underscores the importance of understanding the therapeutic options available for stroke prevention in the primary care setting. This article examines evidence for the use of novel oral anticoagulant (OAC) therapy, including the direct thrombin inhibitor dabigatran and the activated factor X inhibitors rivaroxaban and apixaban for stroke prevention in patients with AF. Although warfarin therapy is the gold standard for prevention of stroke, its use is associated with significant challenges related to drug-drug and food-drug interactions. Warfarin use also requires frequent blood monitoring to maintain anticoagulation within a narrow therapeutic window. Overall, the novel OACs are as good as, or better than, warfarin therapy for stroke prevention in patients with AF, and they have a comparable or reduced risk of associated major bleeding. In addition, the novel OACs have fewer drug-drug and food-drug interactions and do not require continuous blood monitoring. Integration of the novel OACs into clinical practice offers patients with AF new treatment options, and as therapeutic use of the novel OACs increases, real-world experience will add to our understanding of the value of these agents.

New oral anticoagulants in addition to single or dual antiplatelet therapy after an acute coronary syndrome: a systematic review and meta-analysis

Background

Oral anticoagulation in addition to antiplatelet treatment after an acute coronary syndrome might reduce ischaemic events but increase bleeding risk. We performed a meta-analysis to evaluate the efficacy and safety of adding direct thrombin or factor-Xa inhibition by any of the novel oral anticoagulants (apixaban, dabigatran, darexaban, rivaroxaban, and ximelagatran) to single (aspirin) or dual (aspirin and clopidogrel) antiplatelet therapy in this setting.

Methods and results

All seven published randomized, placebo-controlled phase II and III studies of novel oral anticoagulants in acute coronary syndromes were included. The database consisted of 30 866 patients, 4135 (13.4%) on single, and 26 731 (86.6%) on dual antiplatelet therapy, with a non-ST- or ST-elevation acute coronary syndrome within the last 7–14 days. We defined major adverse cardiovascular events (MACEs) as the composite of all-cause mortality, myocardial infarction, or stroke; and clinically significant bleeding as the composite of major and non-major bleeding requiring medical attention according to the study definitions. When compared with aspirin alone the combination of an oral anticoagulant and aspirin reduced the incidence of MACE [hazard ratio (HR) and 95% confidence interval 0.70; 0.59–0.84], but increased clinically significant bleeding (HR: 1.79; 1.54–2.09). Compared with dual antiplatelet therapy with aspirin and clopidogrel, adding an oral anticoagulant decreased the incidence of MACE modestly (HR: 0.87; 0.80–0.95), but more than doubled the bleeding (HR: 2.34; 2.06–2.66). Heterogeneity between studies was low, and results were similar when restricting the analysis to phase III studies.

Conclusion

In patients with a recent acute coronary syndrome, the addition of a new oral anticoagulant to antiplatelet therapy results in a modest reduction in cardiovascular events but a substantial increase in bleeding, most pronounced when new oral anticoagulants are combined with dual antiplatelet therapy.

Supplemental patient education for patients taking oral anticoagulants: systematic review and meta-analysis

OBJECTIVE

Lack of patient knowledge has been associated with poor anticoagulation control, but the effect of patient education on clinical outcomes is unclear. We systematically reviewed the effect of supplemental patient education vs. usual care on hemorrhage, thromboembolic events (TEEs), time in therapeutic range (TTR) and knowledge test scores for all oral anticoagulants.

DATA SOURCES

The data sources were electronic databases, including MEDLINE, EMBASE, CENTRAL, CINAHL and IPA, to February 2012 examining any oral anticoagulant. We reviewed references for additional potentially relevant studies.

METHODS

Only randomized controlled trials (RCTs) were considered. Data extraction and quality assessment were conducted with GRADE. Pooled relative risks (RRs) were calculated, and heterogeneity was determined by use of χ(2) and I(2) statistics.

RESULTS

Seven RCTs (n = 1209) were included in the systematic review, and five RCTs (n = 847) in the meta-analysis. All included studies examined vitamin K antagonists. No significant difference was found for hemorrhage (RR 0.92, 95% confidence interval [CI] 0.04-20.56), TEE (RR 0.66, 95% CI 0.10-4.39), a composite outcome of hemorrhage or TEE (RR 0.48, 95% CI 0.23-1.01), or TTR (mean absolute difference of 2.02%, 95% CI - 2.81 to 6.84). Evidence was conflicting on the impact of supplemental education on test scores. All trials had at least one substantial methodologic limitation.

CONCLUSION

Current evidence does not support supplemental patient education as a means to improve patient outcomes, but the quality of this evidence is poor. Larger randomized trials are needed with longer follow-up, recruitment of patients initiating anticoagulation in primary care settings, and clearly defined education interventions.

Improving anticoagulation management in patients with atrial fibrillation

Three agents have recently been approved to reduce the risk of stroke and embolism, and one agent is in phase 3 trials. These drugs cause less serious bleeding and are simpler to manage, compared with warfarin, but they are not without their risks.

High risk in atrial fibrillation following an ablation procedure: the wide usefulness of the CHADS(2) score

Evaluation of: Chao TF, Ambrose K, Tsao HM et al. Relationship between the CHADS(2) score and risk of very late recurrences after catheter ablation of paroxysmal atrial fibrillation. Heart Rhythm 9(8), 1185-1191 (2012). Limited data are available on the predictors of adverse events and recurrences in patients with atrial fibrillation (AF) after catheter ablation. In a retrospective analysis of 238 patients with paroxysmal AF treated with catheter ablation, it was found that the congestive heart failure, hypertension, age >75 years, diabetes and previous stroke/transient ischemic attack (CHADS(2)) score was an independent predictor of AF recurrences. Moreover, among patients without recurrences at 2 years post-ablation, future recurrence rate during the subsequent follow-up was 64% in those with a CHADS(2) score of less than three, while it was only 3% in patients with a CHADS(2) score of zero. Patients with a higher CHADS(2) score have a different substrate, a more marked disease in the atrium and this may explain the higher rate of recurrence observed after AF ablation. Several more complex scores are available to separately identify the risk of different events in AF: stroke and embolic events, bleeding events, AF recurrences and progression to more sustained forms of AF. Whether it is a better strategy to use the simple CHADS(2) score to rapidly identify a global risk of all future events in AF more widely remains to be determined.

Antithrombotics for stroke prevention in non-valvular atrial fibrillation: an update

Nurses and nurse practitioners play an integral role in initiating and managing antithrombotic prophylaxis in patients with atrial fibrillation (AF). Since the advent of warfarin in the 1950s, there have been few changes in this field until recently. Warfarin has been used for decades and has well-demonstrated efficacy. However, it also has well-known drawbacks, including an unpredictable dose response, need for anticoagulation monitoring, frequent dose adjustments, and many drug and food interactions. A new generation of anticoagulants, which includes direct thrombin inhibitors and selective Factor Xa inhibitors, shows the potential to significantly improve options for antithrombotic prophylaxis and to positively affect patient outcomes. The objective of this review is to update nurses on the new oral anticoagulants, other recent developments, such as improved risk-assessment techniques, and the role of over-the-counter products, including aspirin.

Prevention of Stroke by Antithrombotic Therapy in Patients with Atrial Fibrillation

Atrial Fibrillation (AF) is the most common clinically significant sustained cardiac arrhythmia, a major risk factor for strokes whether it is symptomatic or silent. The older CHADS₂ score and the newer CHADS₂-VASc are well validated to determine stroke risk and guide initiation of antithrombotic therapy, but haemorrhagic risk has to be respected as well, and scores such as HAS-BLED should be widely used. Old fashioned warfarin became standard of care outperforming antiplatelets in every trial but novel classes of anticoagulants that overcome many of warfarin drawbacks have been introduced and are already guideline recommended regiments. Nevertheless their use poses new questions that have to been answered in the near future.

Analysis of Antithrombotic Therapy after Cardioembolic Stroke Due to Atrial Fibrillation or Flutter

Background

Guidelines recommend that all patients with atrial fibrillation and a history of ischemic stroke should receive an anticoagulant. Prior analyses show that warfarin is underutilized in most populations.

Objective

To examine the use of antithrombotic and anticoagulant therapy in patients with atrial fibrillation or flutter during the index hospitalization for acute, ischemic stroke.

Methods

Retrospective electronic medical record review of 200 patients treated at a tertiary care hospital with a primary ICD-9 code for ischemic stroke and a secondary ICD-9 code for atrial fibrillation or flutter. Exclusion criteria were active bleeding, pregnancy, age less than 18, pre-existing warfarin allergy, or dabigatran use.

Results

Fifty-two percent of patients received at least one dose of warfarin during the index hospitalization. There was no relationship between CHADS2 score and likelihood of receiving warfarin ( P > .05). There was no significant difference in adverse event rate in patients receiving warfarin compared to those receiving aspirin (3.8% vs 9.1%; P = .14), but the rate of hemorrhagic transformation was lower in patients receiving warfarin (1% vs 7%; P = .03). The composite of hemorrhagic stroke or hemorrhagic transformation was significantly lower in patients receiving bridging therapy (0% vs 11%; P = .03). Sixteen patients were readmitted for stroke within 3 months of discharge. Ten were readmitted for ischemic stroke, 3 for hemorrhagic stroke or hemorrhagic transformation, and 3 for systemic bleeding. Ten patients (62.5%) were receiving warfarin at readmission, but only one of these patients had a therapeutic INR.

Conclusions

Warfarin was underutilized as secondary stroke prophylaxis in these high-risk patients. Bridging therapy appeared to be safe and was not associated with an increase in adverse events.

Implications of new anticoagulants in primary practice

BACKGROUND

Effective prophylaxis and treatment of thromboembolic disorders remain suboptimal in many healthcare systems, partly owing to limitations of traditional anticoagulants. New oral anticoagulants have been developed and among these, rivaroxaban, apixaban and dabigatran etexilate are in the most advanced stage of clinical development.

METHOD

A literature search using the PubMed and ClinicalTrials.gov databases was performed to identify English-language publications. The search was performed up to 31 December 2011 with the terms rivaroxaban OR Xarelto, apixaban OR Eliquis and dabigatran OR Pradaxa. Ongoing, completed and published phase III randomised controlled trials were selected as the primary source of information for the clinical development programme of each drug.

RESULTS

The new oral agents demonstrate several advantages over traditional anticoagulants, including administration at fixed doses and no requirement for routine coagulation monitoring On the basis of phase III clinical trials, rivaroxaban, apixaban and dabigatran etexilate have been approved in many countries for the prevention of venous thromboembolism after hip and knee replacement surgery. Dabigatran etexilate and rivaroxaban have also been approved for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation in Europe and the US. In addition, rivaroxaban has been approved in Europe for the treatment of acute deep vein thrombosis and prevention of recurrent venous thromboembolism. Approval of these agents and postapproval monitoring of their safety and efficacy will have implications for primary care.

CONCLUSION

Rivaroxaban, apixaban and dabigatran etexilate offer the possibility of simplified prevention and treatment strategies for thromboembolic disorders in the outpatient setting.

Novel oral anticoagulants for stroke prevention in patients with atrial fibrillation

Patients with atrial fibrillation (AF) face an elevated risk of stroke compared with patients who have normal sinus rhythm. Warfarin, an oral vitamin K antagonist, is a highly effective therapeutic agent to reduce stroke risk in patients with AF; however, use of warfarin is complicated by variable patient dose response due to genetic factors and multiple food-drug and drug-drug interactions. Novel oral anticoagulants appear to be a safe, effective alternative to warfarin therapy without the need for routine coagulation monitoring. Dabigatran, a direct thrombin inhibitor, has been commercially available since 2010 for prevention of stroke in patients with nonvalvular AF. More recently, the US Food and Drug Administration (FDA) approved 2 oral activated factor X inhibitors, rivaroxaban and apixaban, for stroke prevention in patients with AF based on clinical trial evidence of their safety and efficacy. In this article, we provide an overview of the 3 novel oral anticoagulants for treating patients with AF and discuss the latest findings from subgroup analyses.

Clinical trials with new oral anticoagulants. Additive value of indirect comparisons also named network meta-analyses

To compare the efficacy and safety of the new oral anticoagulants (NOAC), ideally head-to-head clinical trials should be performed. Given the expense of such an undertaking, it is highly unlikely that such a comparison would be performed. Therefore, there is a need for an unbiased comparative assessment of the benefits and risks of the NOACs, based on the available trial data. Indirect or mixed treatment comparisons may be an useful tool to overcome these limitations also known as network meta-analysis (NMA). The aim of this paper is to give an overview on published NMAs for dabigatran, rivaroxaban and apixaban, each assessed against warfarin in patients with atrial fibrillation, and against enoxaparin in patients undergoing total knee and total hip replacement surgery, in order to obtain insights into the comparability of the adopted methodological techniques.

Transitions of care in anticoagulation management for patients with atrial fibrillation

Thromboprophylaxis with oral anticoagulants (OACs) is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk with anticoagulants comes at the price of increased bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another. Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the OAC, administering vitamin K, when appropriate, to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of OACs in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant. Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by both AF and aging are goals for all patients receiving OACs. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, or particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, and long-term care settings are vital for patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

Care transitions in anticoagulation management for patients with atrial fibrillation: an emphasis on safety

BACKGROUND

Thromboprophylaxis with oral anticoagulants is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk by anticoagulants comes at the price of bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another.

METHODS

This review of the literature focuses on issues specific to the anticoagulation treatment of patients with AF.

RESULTS

Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the oral anticoagulant, administering vitamin K when appropriate to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of oral anticoagulants in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant.

CONCLUSIONS

Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by AF and aging are goals for all patients receiving oral anticoagulants. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, subacute, and long-term care settings are vital in patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

Managing anticoagulation for atrial fibrillation: current issues and future strategies

Although warfarin is superior to aspirin in reducing the risk of stroke in patients with atrial fibrillation, it can increase major bleeds. Hence, physicians stratify patients according to stroke risk to ensure a net benefit. In this review, the CHA(2) DS(2) -VASc stratification scheme used in the latest European Society of Cardiology (2010/12) guidelines will be explained. The greater sensitivity of this scheme, compared to the previous CHADS(2) , more closely delineates patients for whom warfarin is appropriate. The review also anticipates that there will be a wider range of patients who may benefit from the new oral anticoagulants, which show similar or superior efficacy and/or safety to warfarin with a significant reduction in intracranial haemorrhage and do not require routine coagulation monitoring. The role of conventional and new anticoagulant options will also be discussed.

Role of new drugs for management of atrial fibrillation

OBJECTIVE

To evaluate the role of newer agents in the management of atrial fibrillation (AF).

DATA SOURCES

EMBASE and MEDLINE were searched (up to June 2012) combining medication names with atrial fibrillation, humans, clinical trials, and pharmacoeconomic. References of the articles identified and www.clinicaltrials.gov were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

Studies were limited to the English language with clinical or pharmacoeconomic end points followed by the consensus of 3 authors.

DATA SYNTHESIS

Formulated to reduce some of the adverse effects associated with amiodarone by removing the iodine component, dronedarone has improved clinical outcomes over placebo when used in paroxysmal or persistent AF; however, it is less efficacious than amiodarone. Worse outcomes with dronedarone have been seen in patients with heart failure or permanent AF. It has not been compared to antiarrhythmic agents other than amiodarone, and pharmacoeconomic evaluations are lacking. Dabigatran 150 mg is superior to warfarin in preventing stroke or systemic embolism and has been associated with lower rates of vascular-associated mortality. Although the rates of major bleeding were not significantly different between the 2 agents, gastrointestinal bleeding and myocardial infarction occurred more frequently with dabigatran. Dabigatran appears to have the most pharmacoeconomic benefit over warfarin in patients with a higher risk of stroke. Rivaroxaban is noninferior to warfarin for the prevention of stroke and systemic embolism, with no difference in the rates of major bleeding. Cost-effectiveness studies have not been performed with this agent at this time. In patients with AF who were not suitable candidates for warfarin, apixaban is superior to aspirin in preventing stroke or systemic embolism without increasing the risk for major bleeding. Additionally, apixaban is superior to warfarin in preventing stroke or systemic embolism, results in fewer bleeding events, and is associated with lower mortality. Apixaban is not cost-effective against aspirin when used for a short duration but gains superiority with prolonged use or in patients with higher risks of stroke. Additionally, apixaban appears to offer a pharmacoeconomic advantage over warfarin at no to minimal cost. Each new anticoagulant lacks a reversal agent and an assay to detect the presence of the anticoagulant, as well as long-term data when used in the clinical setting.

CONCLUSIONS

Use of dronedarone should be limited to patients with paroxysmal or persistent AF and should not be used in patients with heart failure or with permanent AF. Newer antithrombotic agents appear to be promising alternatives for the prevention of stroke in patients with AF; however, more data are needed to understand their role.

Impact of Atrial Fibrillation On Cardiovascular Mortality in the Setting of Myocardial Infarction

Atrial fibrillation (AF) commonly occurs in patient with acute myocardial infarction (AMI). Potential triggers for AF development in this setting includes reduced left ventricular function, advanced diastolic dysfunction and mitral regurgitation leading to elevated left atrial pressures and atrial stretch. Other triggering mechanisms include inflammation and atrial ischemia. Multiple studies have shown that AF in patients with is associated with increased mortality. However, whether AF is a risk marker or a causal mediator of death remains controversial. There is relative dearth of data with regard to optimal management of AF in the setting of acute coronary syndromes. Patients with AMI who develop AF are at increased risk of stroke. However, the issue of the most appropriate antithrombotic regimens is complex given the need to balance stroke prevention against recurrent coronary events or stent thrombosis and the risk of bleeding. Presently, 'triple therapy' consisting of dual antiplatelet agents plus oral anticoagulants for 3-6 months or longer has been recommended for patients at moderate-high risk of stroke. Atrial fibrillation (AF), the most common sustained arrhythmia seen in clinical practice, often coincides with acute myocardial infarction (AMI), with a reported incidence ranging between 7% and 21%.[1] The development of atrial fibrillation in the acute phase of AMI may aggravate ischemia and heart failure, lead to clinical instability and adversely affect outcome. In the following we will review the pathophysiology, clinical characteristics and importance, and management of AF occurring in the setting of AMI.

Representativeness of the dabigatran, apixaban and rivaroxaban clinical trial populations to real-world atrial fibrillation patients in the United Kingdom: a cross-sectional analysis using the General Practice Research Database

OBJECTIVE

Three oral anticoagulants have reported study results for stroke prevention in patients with atrial fibrillation (AF) (dabigatran etexilate, rivaroxaban and apixaban); all demonstrated superiority or non-inferiority compared with warfarin (RE-LY, ARISTOTLE and ROCKET-AF). This study aimed to assess the representativeness for the real-world AF population, particularly the population eligible for anticoagulants.

DESIGN

A cross-sectional database analysis.

SETTING

Dataset derived from the General Practice Research Database (GPRD). PRIMARY AND SECONDARY OUTCOMES MEASURE: The proportion of real-world patients with AF who met the inclusion/exclusion criteria for RE-LY, ARISTOTLE and ROCKET-AF were compared. The results were then stratified by risk of stroke using CHADS(2) and CHA(2)DS(2)-VASc.

RESULTS

83 898 patients with AF were identified in the GPRD. For the population at intermediate or high risk of stroke and eligible for anticoagulant treatment (CHA(2)DS(2)-VASc ≥1; n=78 783 (94%)), the proportion eligible for inclusion into RE-LY (dabigatran etexilate) was 68% (95% CI 67.7% to 68.3%; n=53 640), compared with 65% (95% CI 64.7% to 65.3%; n=51 163) eligible for ARISTOTLE (apixaban) and 51% (95% CI 50.7% to 51.4%; n=39 892) eligible for ROCKET-AF (rivaroxaban). Using the CHADS(2) method of risk stratification, for the population at intermediate or high risk of stroke and eligible for anticoagulation treatment (CHADS(2) ≥1; n=71 493 (85%)), the proportion eligible for inclusion into RE-LY was 74% (95% CI 73.7% to 74.3%; n=52 783), compared with 72% (95% CI 71.7% to 72.3%; n=51 415) for ARISTOTLE and 56% (95% CI 55.6% to 56.4%; n=39 892) for ROCKET-AF.

CONCLUSIONS

Patients enrolled within RE-LY and ARISTOTLE were more reflective of the 'real-world' AF population in the UK, in contrast with patients enrolled within ROCKET-AF who were a more narrowly defined group of patients at higher risk of stroke. Differences between trials should be taken into account when considering the applicability of findings from randomised clinical trials. However, assessing representativeness is not a substitute for assessing generalisibility, that is, how well clinical trial results would translate into effectiveness and safety in everyday routine care.

Antithrombotic therapy: triple therapy or triple threat?

Antithrombotic therapy plays an essential role in the management of some of the most common and morbid medical conditions. Triple oral antithrombotic therapy (TOAT) is defined as the administration of both therapeutic oral anticoagulation (OAC) and dual antiplatelet therapy (DAPT) to patients with indications for both treatments. The current societal guidelines regarding TOAT are derived from observational studies and some trials of the use of warfarin in addition to antiplatelet therapy in patients with atrial fibrillation and a recent acute coronary syndrome or percutaneous coronary intervention. The general apprehension to administer TOAT is due to the heightened concern for bleeding, rendering warfarin's pharmacokinetic properties concerning. Newer anticoagulant agents may serve as appealing alternatives, and further investigations are warranted. The results of the recent trials that have studied the use of these agents in atrial fibrillation and acute coronary syndrome offer some useful applications to TOAT. Ultimately, selecting the most favorable antithrombotic strategy is going to involve weighing the risks and benefits for each patient.

Treatment of dabigatran-associated bleeding: case report and review of the literature

Dabigatran etexilate is a competitive, direct thrombin inhibitor that works in the coagulation cascade to ultimately prevent thrombus formation. It is recommended by the 2012 American College of Chest Physicians evidence-based clinical practice guidelines as first-line therapy over vitamin k antagonists for long-term antithrombotic therapy in patients with paroxysmal or persistent nonrheumatic atrial fibrillation who are at intermediate to high risk of stroke and systemic embolism (grade 2B). However, serious postmarketing events involving life-threatening bleeding are emerging with no antidote for reversal of the anticoagulant effect being available for use. Potential reversal agents are being used in clinical practice with questionable efficacy and safety profiles. We report a case involving an 84-year-old male with acute kidney injury who developed life-threatening gastrointestinal and surgical site bleeding secondary to dabigatran accumulation. Use of the Naranjo probability scale indicated a probable cause between the bleeding event and dabigatran use. After discontinuation of drug therapy, fresh frozen plasma, recombinant coagulation factor VIIa, and cryoprecipitate were administered as potential reversal agents with negligible benefit. However, this patient appeared to slowly benefit with administration of continuous venovenous hemodialysis. Based upon our experience with this patient and literature review, the most effective treatment algorithm for dabigatran-associated bleeding may be to utilize hemodialysis initially.

Resource Use and Cost Implications of Switching Among Warfarin Formulations in Atrial Fibrillation Patients

Background:

Despite the uncertainty surrounding the safety of switching warfarin formulations, limited data exist on the resource use and costs associated with this switching pattern.

Objective:

To evaluate health care resource use and costs associated with switching warfarin formulations among patients with atrial fibrillation (AF) in a managed care organization.

Methods:

Patients diagnosed with AF (ICD-9 427.31) between July 2004 and August 2008 and who received warfarin therapy were identified in the HealthCore Integrated Research Database and categorized into 3 groups: users of generic warfarin formulations from a single drug manufacturer (generic-only group), users of branded warfarin formulations only (brand-only group), and patients who used generic and branded warfarin therapy interchangeably or who may have used generic drugs from 1 or more manufacturers (generic/brand switching group). Patients were followed 12 months or longer after their index warfarin prescription date to compare all-cause resource use and costs using multivariable regression analysis.

Results:

The analysis included 12,908 patients: 71.82% were in the generic-only group, 9.61% were in the brand-only group, and 18.57% were in the generic/brand switching group. Patients in the generic/brand switching group were more likely to be hospitalized (relative risk [RR] = 1.43, p < 0.0001) or to use emergency department services (RR = 1.20, p < 0.01), compared to the brand-only users. Hospitalizations were more likely (RR = 1.26, p < 0.001) to occur among generic-only users versus brand-only users. Adjusted mean pharmacy costs per member per month were lower in the generic/brand switching group compared to the brand-only group ($257 vs $273, p = 0.038), but inpatient costs were higher ($1250 vs $972, p < 0.001), resulting in higher ($2125 vs $1847, p < 0.001) total costs. Generic-only users had lower pharmacy costs compared to brand-only users ($246 vs $273, p < 0.001), but total health care costs trended to be higher in the generic-only group ($1957 vs $1847, p = 0.053).

Conclusions:

The use of both generic and branded formulations of warfarin interchangeably, or the use of generics from more than 1 manufacturer, was associated with increased use of all-cause health care resources and total costs in patients with AF.

Detection of previously undiagnosed atrial fibrillation in patients with stroke risk factors and usefulness of continuous monitoring in primary stroke prevention

The detection of undiagnosed atrial tachycardia/atrial fibrillation (AT/AF) among patients with stroke risk factors could be useful for primary stroke prevention. We analyzed newly detected AT/AF (NDAF) using continuous monitoring in patients with stroke risk factors but without previous stroke or evidence of AT/AF. NDAF (AT/AF >5 minutes on any day) was determined in patients with implantable cardiac rhythm devices and ≥1 stroke risk factors (congestive heart failure, hypertension, age ≥75 years, or diabetes). All devices were capable of continuously monitoring the daily cumulative time in AT/AF. Of 1,368 eligible patients, NDAF was identified in 416 (30%) during a follow-up of 1.1 ± 0.7 years and was unrelated to the CHADS(2) score (congestive heart failure, hypertension [blood pressure consistently >140/90 mm Hg or hypertension treated with medication], age ≥75 years, diabetes mellitus, previous stroke or transient ischemic attack). The presence of AT/AF >6 hours on ≥1 day increased significantly with increased CHADS(2) scores and was present in 158 (54%) of 294 patients with NDAF and a CHADS(2) score of ≥2. NDAF was sporadic, and 78% of patients with a CHADS(2) score of ≥2 with NDAF experienced AT/AF on <10% of the follow-up days. The median interval to NDAF detection in these higher risk patients was 72 days (interquartile range 13 to 177). In conclusion, continuous monitoring identified NDAF in 30% of patients with stroke risk factors. In patients with NDAF, AT/AF occurred sporadically, highlighting the difficulty in detecting paroxysmal AT/AF using traditional monitoring methods. However, AT/AF also persisted for >6 hours on ≥1 days in most patients with NDAF and multiple stroke risk factors. Whether patients with CHADS(2) risk factors but without a history of AF might benefit from implantable monitors for the selection and administration of anticoagulation for primary stroke prevention merits additional investigation.