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

Mixed treatment comparison meta-analysis of aspirin, warfarin, and new anticoagulants for stroke prevention in patients with nonvalvular atrial fibrillation

BACKGROUND

Warfarin and aspirin are used to prevent stroke in patients with atrial fibrillation (AF). There are inherent challenges with both treatments, including variable and inconsistent benefit and increased bleeding risks. The availability of new anticoagulants offers some alternatives.

OBJECTIVE

A mixed treatment comparison meta-analysis to evaluate direct and indirect treatment data including aspirin, warfarin apixaban, dabigatran, edoxaban, and rivaroxaban for the prevention of primary or secondary stroke in patients with AF.

METHODS

A comprehensive, systematic literature search was conducted to identify randomized trials comparing aspirin, warfarin, apixaban, dabigatran, edoxaban, and rivaroxaban in patients with AF requiring treatment for stroke prevention. Open-label and blinded designs were included if they evaluated any stroke or any bleeding event. Data on stroke and bleeding events were abstracted, verified, evaluated, scored, and entered into Aggregate Data Drug Information System version 1.16 to generate a mixed treatment comparison meta-analysis. Direct and indirect comparisons were evaluated, and we looked for inconsistency in closed loop structures. Data are reported as rate ratios with 95% credible intervals. In addition, we reviewed variance statistics and explored variance with node-splitting models.

RESULTS

Our literature search yielded 30 articles, 21 of which were included. All treatments except aspirin reduced the risk of any stroke compared with placebo. Warfarin (0.43 [0.33-0.57]), apixaban (0.37 [0.27-0.54]), dabigatran (0.34 [0.21-0.57]), rivaroxaban (0.36 [0.22-0.60]), and aspirin with clopidogrel (0.73 [0.53-0.99]) were more protective than aspirin alone. Warfarin and the new anticoagulants were similar in the reduction of stroke, vascular death, and mortality. There was no difference in major bleeding between any treatment group. There were more nonmajor bleeding events when comparing warfarin and apixaban (1.83 [1.05-4.03]); no other differences between warfarin and the other new anticoagulants were found.

CONCLUSIONS

This mixed treatment comparison meta-analysis found similarity between warfarin and the new anticoagulants with the exception of one comparison, in which warfarin was associated with more non-major bleeding than apixaban. Thus, the new anticoagulants are therapeutically comparable when warfarin is inappropriate.

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.

Improvement of anticoagulant treatment using a dynamic decision support algorithm: a Danish Cohort study

INTRODUCTION

Warfarin is the most widely prescribed vitamin K antagonist and in the United States and Europe more than 10 million people are currently in long-term oral anticoagulant treatment. This study aims to retrospectively validate a dynamic statistical model providing dosage suggestions to patients in warfarin treatment.

MATERIALS AND METHODS

The model was validated on a cohort of 553 patients with a mean TTR of 83%. Patients in the cohort were self-monitoring and managed by a highly specialised anticoagulation clinic. The predictive model essentially consists of three parts handling INR history, warfarin dosage and biological noise, which allows for prediction of future INR values and optimal warfarin dose to stay on INR target. Further, the model is based on parameters initially being set to population values and gradually individualised during monitoring of patients.

PRIMARY OUTCOME

Time in therapeutic range was used as surrogate quality measure of the treatment, and model-suggested dosage of warfarin was used to assess the accuracy of the model performance.

RESULTS

The accuracy of the model predictions measured as median absolute error was 0.53 mg/day (interquartile range from 0.25 to 1.0). The model performance was evaluated by the difference between observed and predicted warfarin intake in the preceding week of an INR measurement. In more than 70% of the cases where INR measurements were outside the therapeutic range, the model suggested a more reasonable dose than the observed intake.

CONCLUSION

Applying the proposed dosing algorithm can potentially further increase the time in INR target range beyond 83%.

Non-vitamin K antagonist oral anticoagulants in cardiovascular disease management: evidence and unanswered questions

WHAT IS KNOWN AND OBJECTIVE

Anticoagulation is important in the management of cardiovascular disorders; however, traditional anticoagulants such as heparins and vitamin K antagonists (VKAs) have limitations, including parenteral administration with the former and the need for coagulation monitoring and dose adjustments with the latter. Three non-VKA oral anticoagulants (OACs), dabigatran, rivaroxaban and apixaban, are available for the prevention of stroke in patients with atrial fibrillation (AF) and may change clinical practice. This article reviews current knowledge and important unanswered questions on the use of these agents in patients with cardiovascular disease.

METHODS

A literature search was performed using PubMed and the search terms dabigatran, rivaroxaban, apixaban, AF and acute coronary syndrome (ACS). Peer-reviewed, published clinical trials, review articles, relevant treatment guidelines and prescribing information documents were identified and reviewed for relevance.

RESULTS AND DISCUSSION

Dabigatran is an oral direct thrombin inhibitor; rivaroxaban and apixaban are oral direct Factor Xa inhibitors. These agents have a quicker onset and offset of action, more predictable pharmacokinetic and pharmacodynamic profiles, and fewer drug-drug interactions than VKAs, allowing use of fixed doses. For the prevention of stroke in patients with AF, the non-VKA OACs were either non-inferior or superior to warfarin with similar or improved bleeding profiles, particularly with respect to reductions in intracranial haemorrhage. In patients with ACS receiving dual antiplatelet therapy, the addition of rivaroxaban significantly reduced the rate of death from cardiovascular causes, myocardial infarction or stroke without increasing fatal bleeding, but led to higher rates of major bleeding. Dose reductions with non-VKA OACs are mandated in certain circumstances in patients with AF, such as moderate renal impairment. Contraindications include creatinine clearance <15 mL/min (<30 mL/min for dabigatran in Europe and Canada) and moderate or severe hepatic impairment, but patients can be transitioned to other anticoagulants if appropriate. It is unknown which non-VKA OAC is optimal for stroke prevention in patients with AF, although factors such as co-medications (e.g. dabigatran may be preferred if a patient is taking a co-medication that is a strong cytochrome P450 3A4 inhibitor) and renal function (rivaroxaban and apixaban depend less on renal clearance than dabigatran) will be important for individual patients. Addition of rivaroxaban to antiplatelet therapy for prevention of recurrent events in patients with recent ACS is approved in Europe for patients at the highest risk (with elevated cardiac biomarkers) and must take into account the increased risk of major bleeding. Although routine coagulation monitoring is not required, an understanding of which assays are appropriate for each non-VKA OAC and how they are affected is important. In a bleeding emergency, non-specific prohaemostatic agents are suggested to reverse the action of the non-VKA OACs, but more clinical data are needed.

WHAT IS NEW AND CONCLUSION

Non-VKA OACs provide similar or improved efficacy and, on current evidence, improved safety. They provide greater convenience, compared with traditional anticoagulants for the prevention of stroke in patients with AF. Rivaroxaban may be of benefit to selected high-risk patients with ACS. Selection of the most appropriate non-VKA OAC will depend on individual patient factors.

Treatment patterns associated with stroke prevention in patients with atrial fibrillation in three major cities in the People's Republic of china

BACKGROUND

Atrial fibrillation (AF) is associated with an increased risk of stroke. This study assessed treatment patterns associated with stroke prevention among patients with AF in three major cities of the People's Republic of China.

METHODS

A random sample of 2,862 medical charts for patients with AF at six tertiary hospitals located in Beijing, Shanghai, and Guangzhou between 2003 and 2008 were reviewed. Patient demographics, clinical characteristics, and treatment patterns were extracted from medical charts. Antithrombotic regimens included antiplatelets, anticoagulants, and a combination of both. Descriptive analyses were performed to summarize basic antithrombotic patterns. A logistic regression model examined demographic and clinical factors associated with antithrombotic treatment patterns.

RESULTS

Of the patient sample, 55% were male, the average age was 72 years (49% ≥75 years), 15% had valvular AF, 78% had nonvalvular AF, and the remainder had unspecified AF. CHADS2 scores ≥2 were reported for 53% of patients. Antithrombotic treatment was not received by 17% of patients during hospitalization, and 66% did not receive warfarin. Among patients with valvular or nonvalvular AF, 33%, 30%, and 20% received antiplatelet, anticoagulation, and antiplatelet plus anticoagulation treatments, respectively. For patients with CHADS2 scores of 0, 1, 2, 3, and ≥4, 52%, 42%, 28%, 21%, and 21%, respectively, were treated with warfarin. Predictors of no antithrombotic treatment included age and hospital location.

CONCLUSION

Anticoagulation therapy was underused in Chinese patients with AF. Antithrombotic treatment was not associated with stroke risk. Further studies need to examine the clinical consequences of various antithrombotic treatment patterns in Chinese patients with AF.

New oral anticoagulants for atrial fibrillation: are they worth the risk?

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the U.S. Anticoagulation is recommended for stroke prevention in AF patients with intermediate-to-high stroke risk (i.e., patients with a CHADS2 score of 1 or greater). Warfarin was previously the only option for oral anticoagulation in these patients, but three new oral anticoagulants have become available as alternatives for warfarin in patients with nonvalvular AF. The advantages of the newer agents include a rapid onset, predictable pharmacokinetics, and no need for routine anticoagulation monitoring. Dabigatran (Pradaxa) and apixaban (Eliquis) have demonstrated improved efficacy compared with warfarin. Rivaroxaban (Xarelto) was non-inferior to warfarin for stroke prevention in AF. Apixaban demonstrated a reduced incidence of major bleeding compared with warfarin and a reduction in all-cause mortality. Limitations to the use of the new oral anticoagulants include the lack of a reversal agent; an inability to use the therapies in specific patient populations (such as those with severe renal or hepatic impairment); limited experience with drug-drug and drug-disease interactions; and a lack of available coagulation tests to quantify their effects. Although the newer agents have higher acquisition costs, the benefits of cost savings may be derived from the potential for decreasing the incidence of hemorrhagic stroke and intracranial bleeding and reducing the need for anticoagulation monitoring. Benefits and risks should be carefully weighed before these agents are prescribed for patients presenting with new-onset AF.

Practical considerations for using novel oral anticoagulants in patients with atrial fibrillation

Novel oral anticoagulants, including dabigatran, rivaroxaban, and apixaban, represent new options for preventing stroke in patients with atrial fibrillation, as shown by the results from large, randomized phase III trials. Because of their greater specificity, rapid onset of action, and predictable pharmacokinetics, the novel oral anticoagulants (dabigatran, rivaroxaban, and apixaban) address several limitations of warfarin or other vitamin K antagonists in day-to-day clinical practice. However, a range of practical questions relating to the novel oral anticoagulants has emerged, including topics such as patient selection, treatment of patients with renal impairment, risk of myocardial infarction, drug interactions, switching between anticoagulants, and management of bleeding, in addition to use of these agents in patients requiring antiplatelet drug treatment or undergoing cardioversion or percutaneous interventions (eg, ablation). In this review, practical aspects of the use of novel oral anticoagulants in patients with atrial fibrillation are discussed, with reference to available data and guidance from prescribing information.

Anticoagulation and Clinical Outcomes in Heart Failure Patients With Atrial Fibrillation: Findings From the ADHERE Registry

The risks and benefits of anticoagulation for patients with both heart failure and atrial fibrillation are unclear. We hypothesized that anticoagulation was associated with improved clinical outcomes of heart failure patients with atrial fibrillation independent of other risk factors. We conducted a retrospective cohort study of clinical registry data linked to Medicare claims for new users of oral anticoagulation (warfarin) without contraindications, discharged home alive, and stratified by CHADS₂ score. Outcomes of interest were propensity score-adjusted estimates of the effects of warfarin at discharge on all-cause mortality, thromboembolic events, major adverse cardiovascular events, and bleeding events. Among 10,494 patients with heart failure and atrial fibrillation, the 2249 patients newly treated with warfarin had lower 1-year mortality (27.7% vs 39.3% for CHADS₂ score ≤ 3 [P > .001]; 31.6% vs 41.8% for CHADS₂ score > 3 [P > .001]) than patients not treated with warfarin. There was no significant difference in thromboembolic events, major adverse cardiovascular events, or bleeding events at 1 year. After multivariate adjustment, exposed individuals in both CHADS₂ subgroups had lower adjusted 1-year mortality (CHADS₂ ≤ 3: hazard ratio, 0.78 [95% confidence interval, 0.69-0.89]; CHADS₂ >3: 0.78 [0.66-0.93]). In conclusion, warfarin use in heart failure patients with atrial fibrillation was associated with improved survival at 1 year independent of baseline CHADS₂ score. However, there was no significant reduction in clinical events, such as thromboembolic or major adverse cardiovascular events at 1 year that might simply explain the survival benefit associated with warfarin.

Dabigatran, Rivaroxaban, or Apixaban versus Warfarin in Patients with Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-Analysis of Subgroups

Background. New oral anticoagulants (NOAC; rivaroxaban, dabigatran, apixaban) have become available as an alternative to warfarin anticoagulation in non-valvular atrial fibrillation (NVAF). Methods. MEDLINE and CENTRAL, regulatory agencies websites, clinical trials registers and conference proceedings were searched to identify randomised controlled trials of NOAC versus warfarin in NVAF. Two investigators reviewed all studies and extracted data on patient and study characteristics along with cardiovascular outcomes. Relative risks (RR) and 95% confidence intervals (CI) were estimated using a random effect meta-analysis. Results. Three clinical trials in 50,578 patients were included. The risk of non-hemorrhagic stroke and systemic embolic events (SEE) was similar with the NOAC and warfarin (RR = 0.93; 95% CI = 0.83–1.04), while the risk of intracranial bleeding (ICB) with the NOAC was lower than with warfarin (RR = 0.46; 95% CI = 0.33–0.65). We found differences in the effect size on all strokes and SEE depending on geographic region as well as on non-hemorrhagic stroke, SEE, bleeding and mortality depending on time in therapeutic range. Conclusion. The NOAC seem no more effective than warfarin for prevention of nonhemorrhagic stroke and SEE in the overall NVAF population, but are generally associated with a lower risk of ICB than warfarin.

Dabigatran Use in the Real World

Dabigatran etexilate, an oral direct thrombin inhibitor, was approved by the Food and Drug Administration to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation based on the outcomes of the Randomized Evaluation of Long-term anticoagulant therapY (RE-LY) study. Although this study provides robust data on the efficacy and safety of dabigatran, there may be differences in the drug use and outcomes in routine clinical practice following drug approval. In this retrospective chart review study, we describe the use of dabigatran in 160 patients in 4 adult hospitals (1 academic and 3 community), including appropriate prescribing for indication, starting dose, concomitant anticoagulant and antiplatelet use, and clinical outcomes such as bleeding, myocardial infarction, and stroke. The study revealed appropriate indication of nonvalvular atrial fibrillation in 145 (91%) of the 160 patients. The dose of dabigatran was appropriate in 90% of the patients, with the most common cause of inappropriate dosing due to perceived bleeding risk. Over a follow-up period of 6 months, bleeding complications were noted in 6 patients still taking dabigatran, 5 of which were gastrointestinal bleeding. Our study underscores the importance of prescriber education regarding the appropriate indication, dosage, and safety of dabigatran with active participation of pharmacists in this process.

New oral anticoagulants and the cancer patient

Indications for anticoagulation are common in patients with malignancy. Cancer patients have an increased risk of developing venous thromboembolic events or may have other indications for anticoagulation, such as atrial fibrillation. New oral anticoagulants (NOACs) are now available that offer increased options for anticoagulation beyond the traditional vitamin K antagonists and low molecular weight heparins that have long been the cornerstone of treatment. This review will focus on the three NOACs that are currently approved for use in the U.S.: the direct thrombin inhibitor, dabigatran, and the factor Xa inhibitors, apixaban and rivaroxaban. Oncologists are likely to encounter an increasing number of patients taking these agents at the time of their cancer diagnosis or to have patients who develop indications for anticoagulation during the course of their disease. The basic pharmacology, current clinical indications, and approach to the use of NOACs in the cancer patient will be reviewed.

Evaluation of dabigatran exposures reported to poison control centers

BACKGROUND

Dabigatran is a novel oral anticoagulant for which a well-defined range of toxicity and proven antidote has not been established.

OBJECTIVE

The primary objective of this study was to characterize dabigatran exposures reported to poison centers by dose ingested, clinical effects, treatments used, and managment sites to gain a better understanding of patient outcomes.

METHODS

A retrospective database review was conducted for dabigatran exposures reported to the National Poison Data System for the American Association of Poison Control Centers (AAPCC) over the period October 2010 to December 2012.

RESULTS

There were 802 human dabigatran exposures involving adults predominantly (91% of cases). Exposure chronicity was acute in 43%, acute-on-chronic in 46%, and chronic in 11%, with the most common reason for an exposure call being an unintentional therapeutic error (70.6%). The most common management sites were on-site in 72% of cases and within a health care facility for 26%. Bleeding events and coagulopathies were the most commonly observed clinical effects. Treatments administered included activated charcoal, blood and coagulation products, hemodialysis, and supportive measures. Confirmed outcomes included death in 13 patients (1.6%), major effects in 23 (2.9%), and moderate effects in 50 (6.2%). More severe outcomes were significantly associated with adverse drug reactions, patients ≥65 years of age, those treated with blood and coagulation products and/or dialysis, and renal dysfunction (P < .05). Children experienced few moderate effects and no major effects or deaths.

CONCLUSIONS

Severe outcomes from dabigatran exposures were not common, occurring in approximately 5% of cases.

Cardioversion in Acute Atrial Fibrillation Without Anticoagulation

A major concern in cardioversion of newly detected atrial fibrillation is the risk of thromboembolic events. The vast majority of these events occur in the first week following cardioversion. Transesophageal echocardiography has demonstrated that thrombus and dense spontaneous echo contrast may occur in the left atrium and left atrial appendage in patients with acute atrial fibrillation (<48 hours) scheduled for cardioversion. Moreover, atrial function may become impaired immediately following successful cardioversion. The risk of thromboembolic events increases with the presence of stroke risk factors, such as heart failure, hypertension, diabetes, prior stroke, female sex and age above 65-75 years. Thus, the current guidelines of the ESC and ACC/AHA/Heart Rhythm Society recommend that patients with acute atrial fibrillation should undergo cardioversion under cover of unfractionated or low-molecular weight heparin followed by oral anticoagulation for at least 4 weeks in patients in patients at moderate-to-high risk for stroke. In line with the guidelines, new evidence from a large patient population suggests that after successful cardioversion of acute atrial fibrillation, patients have a low overall risk of thromboembolic events without any anticoagulation when they have no risk factors for thromboembolism. In contrast, the risk is in the range of 10% in patients with multiple classic risk factors for thromboembolism.

Joint use of cardio-embolic and bleeding risk scores in elderly patients with atrial fibrillation

BACKGROUND

Scores for cardio-embolic and bleeding risk in patients with atrial fibrillation are described in the literature. However, it is not clear how they co-classify elderly patients with multimorbidity, nor whether and how they affect the physician's decision on thromboprophylaxis.

METHODS

Four scores for cardio-embolic and bleeding risks were retrospectively calculated for ≥ 65 year old patients with atrial fibrillation enrolled in the REPOSI registry. The co-classification of patients according to risk categories based on different score combinations was described and the relationship between risk categories tested. The association between the antithrombotic therapy received and the scores was investigated by logistic regressions and CART analyses.

RESULTS

At admission, among 543 patients the median scores (range) were: CHADS2 2 (0-6), CHA2DS2-VASc 4 (1-9), HEMORR2HAGES 3 (0-7), HAS-BLED 2 (1-6). Most of the patients were at high cardio-embolic/high-intermediate bleeding risk (70.5% combining CHADS2 and HEMORR2HAGES, 98.3% combining CHA2DS2-VASc and HAS-BLED). 50-60% of patients were classified in a cardio-embolic risk category higher than the bleeding risk category. In univariate and multivariable analyses, a higher bleeding score was negatively associated with warfarin prescription, and positively associated with aspirin prescription. The cardio-embolic scores were associated with the therapeutic choice only after adjusting for bleeding score or age.

CONCLUSION

REPOSI patients represented a population at high cardio-embolic and bleeding risks, but most of them were classified by the scores as having a higher cardio-embolic than bleeding risk. Yet, prescription and type of antithrombotic therapy appeared to be primarily dictated by the bleeding risk.

An explanation of recommendation differences: illustrations from recent atrial fibrillation guidelines

The development of guidelines and their use in all areas of medicine has greatly expanded in recent years. However, despite a shared evidence base, recommendations provided by different professional societies and healthcare authorities often vary considerably. The rapid advances in atrial fibrillation (AF) and the multiplicity of guidelines devoted to AF have made it particularly susceptible to this problem. Many nonmedical aspects are important in the development of guidelines, and without understanding them correct interpretation of guidelines is difficult. Conflicts of interest, the regulatory environment, and local data all influence guidelines. Nuanced wording, resource availability, and strategic purpose add complexity to guideline recommendations. This article reviews major AF guidelines from around the world and discusses aspects which have nothing to do with the scientific evidence base in order to help the practicing physician understand and make better use of differing guideline recommendations.

Impact of atrial fibrillation on stroke-related healthcare costs

BACKGROUND

Limited data exist on the economic implications of stroke among patients with atrial fibrillation (AF). This study assesses the impact of AF on healthcare costs associated with ischemic stroke (IS), hemorrhagic stroke (HS), or transient ischemic attack (TIA).

METHODS AND RESULTS

A retrospective analysis of MarketScan claims data (2005-2011) for AF patients ≥18 years old with ≥1 inpatient claim for stroke, or ≥1 ED or inpatient claim for TIA as identified by ICD-9-CM codes who had ≥12 months continuous enrollment prior to initial stroke. Initial event- and stroke-related costs 12 months post-index were compared among patients with AF and without AF. Adjusted costs were estimated, controlling for demographics, comorbidities, anticoagulant use, and baseline resource use. Data from 23,807 AF patients and 136,649 patients without AF were analyzed. Unadjusted mean cost of the index event was $20,933 for IS, $59,054 for HS, $8616 for TIA hospitalization, and $3395 for TIA ED visit. After controlling for potential confounders, adjusted mean incremental costs (index plus 12-month post-index) for AF patients were higher than those for non-AF patients by: $4726, $7824, and $1890 for index IS, HS, TIA (identified by hospitalization), respectively, and $1700 for TIA (identified by ED) (all P<0.01). In multivariate regression analysis, AF was associated with a 20% (IS), 13% (HS), and 18% (TIA) increase in total stroke-related costs.

CONCLUSION

Stroke-related care for IS, HS, and TIA is costly, especially among individuals with AF. Reducing the risk of AF-related stroke is important from both clinical and economic standpoints.

Evaluation of pharmacist-managed dabigatran in an inpatient setting

BACKGROUND

Although therapeutic drug monitoring is not required for patients receiving dabigatran to determine therapeutic efficacy, there are a number of other factors to consider. Currently, there are no studies evaluating pharmacist-led management of dabigatran.

OBJECTIVE

The role of inpatient pharmacists related to the management of dabigatran was evaluated.

METHODS

All adult patients who received at least 1 dose of dabigatran with a length of stay greater than 24 hours in a single-center, community hospital between May 2011 and August 2012 were retrospectively reviewed (n = 176).

RESULTS

Almost half of the patients (46%) required pharmacist intervention related to dabigatran management during hospital admission. Of patients receiving dabigatran prior to hospital admission, 18.4% were admitted on an inappropriate home dose. Transitioning between dabigatran and alternative anticoagulants accounted for the majority of pharmacist interventions (74.2%), with patients transitioning from unfractionated heparin to dabigatran occurring most frequently. Renal impairment requiring dose adjustment or drug discontinuation occurred in 6.3% of patients, whereas 6.8% of patients required pharmacist intervention for procedural anticoagulation. Inpatient therapy was determined to be relatively safe, with few patients (1.7%) requiring permanent discontinuation of dabigatran as a result of a bleeding complication.

CONCLUSION

Pharmacists significantly contributed to the safe and appropriate use of dabigatran during hospitalization.

Use of novel oral anticoagulants for patients with atrial fibrillation: systematic review and clinical implications

Atrial fibrillation (AF), a common arrhythmia, increases the risk of ischemic stroke. Stroke and bleeding scores for patients with AF can help to stratify risk and determine the need for antithrombotic therapy, for which warfarin has been the gold standard. Although highly effective, warfarin has several limitations that can lead to its underuse. Data from randomized, Phase III clinical trials of the novel oral anticoagulants, dabigatran, a direct thrombin inhibitor, and rivaroxaban and apixaban, both factor Xa inhibitors, indicate these drugs are at least noninferior to warfarin for the prevention of stroke and systemic embolism. They are easier to administer, and have an equivalent or lower risk of bleeding versus warfarin. A better understanding of the risks and benefits of the novel oral anticoagulants, and their use in clinical practice, will prepare clinicians to anticipate and address educational and clinical needs of AF patients and their families, and promote evidence-based prescription of appropriate and safe anticoagulation therapy.

Preventing stroke in patients with atrial fibrillation

Adults with atrial fibrillation are at an increased risk for stroke. New oral antithrombotic agents are now available to help prevent stroke and other thromboembolic events. This article provides an update on factors to consider when determining various treatment options for these high-risk patients in hopes of improving outcomes.

Managing atrial fibrillation in the global community: The European perspective

Atrial fibrillation is a common, global problem, with great personal, economic and social burdens. As populations age it increases in prevalence and becomes another condition that requires careful chronic management to ensure its effects are minimised. Assessment of the risk of stroke using well established risk prediction models is being aided by modern computerised databases and the choice of drugs to prevent strokes is ever expanding to try and improve the major cause of morbidity in AF. In addition, newer drugs for controlling rhythm are available and guidelines are constantly changing to reflect this. As well as medications, modern techniques of electrophysiology are becoming more widely embraced worldwide to provide more targeted treatment for the underlying pathophysiology. In this review we consider these factors to concisely describe how AF can be successfully managed.

Warfarin for prevention of thrombosis among long-term care residents with atrial fibrillation: evidence of continuing low use despite consideration of stroke and bleeding risk

Objectives

The aims of the study were to evaluate usage rates of warfarin in stroke prophylaxis and the association with assessed stages of stroke and bleeding risk in long-term care (LTC) residents with atrial fibrillation (AFib).

Methods

A cross-sectional analysis of two LTC databases (the National Nursing Home Survey [NNHS] 2004 and an integrated LTC database: AnalytiCare) was conducted. The study involved LTC facilities across the USA (NNHS) and within 19 states (AnalytiCare). It included LTC residents diagnosed with AFib (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] diagnostic code 427.3X). Consensus guideline algorithms were used to classify residents by stroke risk categories: low (none or 1+ weak stroke risk factors), moderate (1 moderate), high (2+ moderate or 1+ high). Residents were also classified by number of risk factors for bleeding (0–1, 2, 3, 4+). Current use of warfarin was assessed. A logistic regression model predicted odds of warfarin use associated with the stroke and bleeding risk categories.

Results

The NNHS and AnalytiCare databases had 1,454 and 3,757 residents with AFib, respectively. In all, 34 % and 45 % of residents with AFib in each respective database were receiving warfarin. Only 36 % and 45 % of high-stroke-risk residents were receiving warfarin, respectively. In the logistic regression model for the NNHS data, when compared with those residents having none or 1+ weak stroke risk and 0–1 bleeding risk factors, the odds of receiving warfarin increased with stroke risk (odds ratio [OR] = 1.93, p = 0.118 [1 moderate risk factor]; OR = 3.19, p = 0.005 [2+ moderate risk factors]; and OR = 8.18, p ≤ 0.001 [1+ high risk factors]) and decreased with bleeding risk (OR = 0.83, p = 0.366 [2 risk factors]; OR = 0.47, p ≤ 0.001 [3 risk factors]; OR = 0.17, p ≤ 0.001 [4+ risk factors]). A similar directional but more constrained trend was noted for the AnalytiCare data: only 3 and 4+ bleeding risk factors were significant.

Conclusions

The results from two LTC databases suggest that residents with AFib have a high risk of stroke. Warfarin use increased with greater stroke risk and declined with greater bleeding risk; however, only half of those classified as appropriate warfarin candidates were receiving guideline-recommended anticoagulant prophylaxis.

Comparison of Medical Costs of Patients With Atrial Fibrillation Unsuitable for Warfarin Treatment With Apixaban or Aspirin Based on AVERROES Trial

Background:

The AVERROES trial name is the following: The Apixaban Versus Acetylsalicylic Acid (ASA) to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment (AVERROES) trial demonstrated that apixaban reduced the risk of stroke relative to aspirin, without significantly increasing major bleeding risk in patients with atrial fibrillation (AF) considered unsuitable for warfarin therapy. Based on AVERROES trial results, this study compared the medical costs for clinical end points among patients with AF treated with either apixaban or aspirin.

Methods:

Medical costs per patient-year for clinical events were determined. Based on clinical event rates for patients in the AVERROES trial, medical costs excluding drug costs were estimated for apixaban- and aspirin-treated patient groups.

Results and Conclusions:

Based on AVERROES trial results, among patients with AF unsuitable for warfarin therapy, apixaban use was estimated to be associated with a mean medical cost avoidance of US$735 in a patient-year relative to aspirin. The primary driver was the significant reduction in ischemic stroke rate. The medical cost reduction associated with apixaban use was consistent in sensitivity analyses.

Incidence and cost of stroke and hemorrhage in patients diagnosed with atrial fibrillation in France

BACKGROUND

Stroke represents a major complication of atrial fibrillation (AF). The current anticoagulation options for stroke prevention increase hemorrhage risk. The objective of the study was to estimate the incidence and costs of hospitalization for stroke and hemorrhage in patients with AF who are eligible for stroke prevention.

METHODS

Patients hospitalized for AF were identified from the French National hospital database (Programme Médicalisé des Systèmes d'Information) and a calculated stroke risk score (congestive heart failure, hypertension [blood pressure consistently >140/90 mm Hg], age ≥75 years, diabetes mellitus, and previous stroke, transient ischemic attack [CHADS2]). Adult patients eligible for stroke prevention (CHADS2 >0) were enrolled. The incidence of hospitalization for stroke and hemorrhage was calculated over a 2-year period. Costs of acute care were determined using diagnosis related groups (DRGs) and corresponding National Hospital Tariffs. Rehabilitation costs were analyzed for patients with strokes and classified by stroke severity.

RESULTS

Sixty-one thousand five hundred eighty-two patients were identified with a mean age of 75.0 ± 11.0 years and a mean CHADS2 score of 1.90 ± 0.99. The 24-month cumulative incidence of any stroke was 32.1 cases/1,000 patients with AF (ischemic, 60%; hemorrhagic, 24%; unspecified, 16%), and that of hemorrhage was 53.1 cases/1,000 patients with AF (gastrointestinal, 26%; intracranial, 5%; other, 69%). The mean costs of ischemic and hemorrhagic strokes were €4,848 and €7,183 (mild), €10,909 and €14,298 (moderate), €29,065 and €29,701 (severe), and €6,035 and €4,590 (fatal), respectively. The mean costs of hemorrhage by type were €3,601 (gastrointestinal), €7,331 (intracranial), €3,941 (other major), and €2,552 (nonmajor).

CONCLUSIONS

The incidence and cost of hospitalization for hemorrhage should be considered in the global burden of AF. These data should be useful for pharmacoeconomic evaluation of new oral anticoagulant medications. Such real-world studies may be relevant for monitoring mid- to long-term morbidity and mortality in the AF population.

Triple Antiplatelet Therapy and Combinations with Oral Anticoagulants After Stent Implantation

Triple oral anticoagulation or triple antiplatelet therapies may be administered for various reasons. They reduce cardiac complications following percutaneous coronary intervention and stroke or other thromboembolic phenomenon in conditions such as atrial fibrillation. There is an elevated risk of severe bleeding, so it is necessary to balance risk and benefits. Newer oral anticoagulants and antiplatelet drugs may be considered; the number of options is increasing. This article examines triple therapies and the efficacy and safety of combinations of traditional anticoagulant and antiplatelet drugs, and reviews clinical trial data on novel agents. Guidelines to inform clinical decision-making are presented.

Factors influencing doctors' selection of dabigatran in non-valvular atrial fibrillation

RATIONALE, AIMS AND OBJECTIVES

This study was designed to examine the factors that influence doctors' decision in initiating or switching from warfarin to dabigratran.

METHOD

A survey questionnaire was sent to 181 doctors who were most likely to prescribe dabigatran (e.g. cardiologists and general internists) at the University of California, San Francisco Medical Center between November 2011 and February 2012. Survey participants were asked to complete an electronic or a paper version of the questionnaire, which consisted of 17 multiple-choice questions. Fisher's exact test and Cochran-Mantel-Haenszel test were used to compare survey responses between cardiologists and general internists.

RESULTS

A total of 65 survey responses were received (35.9% response rate). There were 13 cardiologists and 51 general internists who participated in the study. Cost (25%), renal function (21%) and CHADS2 score (18%) were the three factors doctors considered most often to determine a patient's eligibility for dabigatran in warfarin-naïve patients. On the other hand, histories of unstable international normalized ratio (37%) and missed appointments (17%) along with cost (19%) were most often considered in patients on warfarin. Cardiologists had prescribed dabigatran more often and had a significantly higher level of comfort with prescribing the drug than general internists (P = 0.003; 77% vs. 27%).

CONCLUSIONS

Cost was the most important factor influencing doctors' decision to prescribe dabigatran. Safety and effectiveness of dabigatran as well as patient preference were additional factors influencing their decision. General internists were less comfortable with prescribing dabigatran than cardiologists.

Bleeding as an outcome among patients with nonvalvular atrial fibrillation in a large managed care population

BACKGROUND

Patients with nonvalvular atrial fibrillation (NVAF) are at increased risk for stroke and bleeding events, but bleeding as an outcome has not been extensively studied in this patient population.

OBJECTIVES

The goal of this study was to estimate the incidence of bleeding events among patients with NVAF enrolled in managed care, investigate the relationships between bleeding incidence and bleeding and stroke risks, and estimate health care costs for patients who had a major bleeding event.

METHODS

Adults with commercial insurance or Medicare Advantage coverage and health care claims related to AF between January 2005 and June 2009 but with no evidence of valvular disease were included in this retrospective claims data analysis. Baseline stroke risk (CHADS2 [Congestive Heart Failure, Hypertension, Age >75 Years, Diabetes Mellitus, and Prior Stroke or Transient Ischemic Attack]) and bleeding risk (HAS-BLED [Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile International Normalized Ratios, Elderly, Drugs/Alcohol]) were estimated. Bleeding events were identified during the variable follow-up period, which lasted from the date of the first qualifying AF visit until the earlier of death, disenrollment from the health plan, or June 30, 2010. Bleeding events were classified as major, serious nonmajor, or minor. Health care costs for patients with major bleeding events were calculated.

RESULTS

Among 48,260 patients with NVAF (mean age, 67 years), 34% had an incident bleeding event during a mean (SD) follow-up period of 802 (540) days. Incidence rates for bleeding events of any severity and major events were 29.6 and 10.4 per 100 patient-years, respectively. Bleeding incidence rates increased with greater CHADS2 and HAS-BLED risk scores. All-cause health care costs for patients during a major bleeding event averaged $16,830. Average costs per patient with a major event increased from approximately $52 per day in the prebleeding period to approximately $63 per day in the postbleeding period. Costs for patients who did not experience a major bleeding event averaged approximately $38 per day.

CONCLUSIONS

Bleeding incidence among patients with NVAF in a real-world setting was high and increased with greater stroke and bleeding risk scores. Health care costs for patients with major bleeding events were elevated. All rights reserved.

Racial differences in the prevalence and outcomes of atrial fibrillation among patients hospitalized with heart failure

Background

The intersection of heart failure (HF) and atrial fibrillation (AF) is common, but the burden of AF among black patients with HF is poorly characterized. We sought to determine the prevalence of AF, characteristics, in‐hospital outcomes, and warfarin use associated with AF in patients hospitalized with HF as a function of race.

Methods and Results

We analyzed data on 135 494 hospitalizations from January 2006 through January 2012 at 276 hospitals participating in the American Heart Association's Get With The Guidelines HF Program. Multivariable logistic regression models using generalized estimating equations approach for risk‐adjusted comparison of AF prevalence, in‐hospital outcomes, and warfarin use. In this HF population, 53 389 (39.4%) had AF. Black patients had markedly less AF than white patients (20.8% versus 44.8%, P<0.001). Adjusting for risk factors and hospital characteristics, black race was associated with significantly lower odds of AF (adjusted odds ratio 0.52, 95% CI 0.48 to 0.55, P<0.0001). There were no racial differences in in‐hospital mortality; however, black patients had a longer length of stay relative to white patients. Black patients compared with white patients with AF were less likely to be discharged on warfarin (adjusted odds ratio 0.76, 95% CI 0.69 to 0.85, P<0.001).

Conclusions

Despite having many risk factors for AF, black patients, relative to white patients hospitalized for HF, had a lower prevalence of AF and lower prescription of guideline‐recommended warfarin therapy.

[The management of atrial fibrillation and characteristics of its current care in outpatients. AFABE observational study]

AIM

To provide insights into the characteristics and management of outpatients when their atrial fibrillation (AF) was first detected: diagnosis, treatment and follow-up in the context of the public health system.

DESIGN

AFABE is an observational, multicentre descriptive study with retrospective data collection relating to the practice patterns, management and initial strategies of treatment of patients with diagnosed AF in the context of primary care, emergency and cardiologists of the public health system.

SETTING

Primary and Specialist care. Baix Ebre region. Tarragona. Spain.

SUBJECTS

A representative sample of 182 subjects > 60-year-old with AF who have been randomized, recruited among the registered patients with AF in 22 primary care centres in the area of the study.

MESUREMENTS

Demographic data, comorbidities (AF), CHA2DS2-VASc and HAS_BLED scores, and practice patterns results between Primary Care and referral services.

RESULTS

A total of 182 patients were included (mean age 78.5 SD:7.3 years; 50% women). Most patients (68.3% 95%CI; 60.3-76.3) had the first contact in Primary Care, of which 56.3% (95%CI; 45.2-66.0) were sent to Hospital Emergency Department where 72.7% (95%CI: 63.5-79.0) of the oral anticoagulation and 58.4% (95%CI: 49.4-66.9) of antiarrhytmic treatments were started. More than half (55.9%:95%CI; 47.2-64.7, of patients with permanent AF were followed-up by the Cardiology department.

CONCLUSIONS

Most patients with newly diagnosed AF made a first contact with Primary Care, but around half were sent to Hospital Emergency departments, where they were treated with an antiarrhythmic and/or oral anticoagulation.

Recurrent intraventricular thrombus six months after ST-elevation myocardial infarction in a diabetic man: a case report

BACKGROUND

Percutaneous coronary intervention with placement of a drug-eluting stent in a diabetic patient with ST-elevation myocardial infarction is a relatively common procedure, and always requires subsequent treatment with dual antiplatelet therapy. It is sometimes necessary to add oral anticoagulation therapy because of individual clinical circumstances, which further increases the risk of bleeding.

CASE PRESENTATION

A 66-year-old hypertensive diabetic man with a history of gastrointestinal bleeding was admitted with an ST-elevation inferior myocardial infarction that had been evolving over 72 h. Electrocardiography showed ST segment elevation in the inferior leads and Q waves in the inferior and anterior leads. He reported a similar episode of chest pain 1 month previously, for which he had not sought medical treatment. Coronary angiography showed chronic occlusion of the mid-left anterior descending coronary artery, and acute occlusion of the mid-right coronary artery. He was treated by percutaneous coronary intervention, with placement of a drug-eluting stent in the right coronary artery. Soon after admission, transthoracic echocardiography showed abnormal left ventricular contractility and a large left intraventricular thrombus. Three weeks after admission, the patient was discharged on dual antiplatelet therapy (clopidogrel and aspirin) and oral anticoagulation therapy (acenocoumarol). Four months after discharge, transthoracic echocardiography showed absence of left ventricular thrombus and resolution of the abnormal contractility in the area supplied by the revascularized right coronary artery. Given the high risk of bleeding, oral anticoagulation therapy was stopped. Six months later, transthoracic echocardiography showed recurrent left ventricular apical thrombus, and an underlying hypercoagulable state was ruled out. Oral anticoagulation therapy was restarted on an indefinite basis, and dual antiplatelet therapy was continued.

CONCLUSIONS

The present case illustrates the need for repeat transthoracic echocardiography following the withdrawal of oral anticoagulation therapy in patients with ST-elevation myocardial infarction, both to monitor thrombus status and to assess left ventricular segmental contraction. In patients who require anticoagulation, avoidance of a drug-eluting stent is strongly preferred and second-generation stents are recommended. The alternative regimen of oral anticoagulation and clopidogrel may be considered in this scenario. In patients with recurrent intraventricular thrombus an underlying hypercoagulable state should be ruled out.

Laboratory testing of rivaroxaban in routine clinical practice: when, how, and which assays

A number of target-specific oral anticoagulants (TSOAs) have been developed in recent years, and some have shown considerable promise in large-scale, randomized clinical trials in the prevention and treatment of thromboembolism. Unlike traditional anticoagulants, such as vitamin K antagonists, these TSOAs exhibit predictable pharmacokinetics and pharmacodynamics. Among these agents, rivaroxaban, a direct Factor Xa inhibitor, has been approved for clinical use in many countries for the management of several thromboembolic disorders. As with the other TSOAs, rivaroxaban is given at fixed doses without routine coagulation monitoring. However, in certain patient populations or special clinical circumstances, measurement of drug exposure may be useful, such as in suspected overdose, in patients with a haemorrhagic or thromboembolic event during treatment with an anticoagulant, in those with acute renal failure, or in patients who require urgent surgery. This article summarizes the influence of rivaroxaban on commonly used coagulation assays and provides practical guidance on laboratory testing of rivaroxaban in routine practice. Both quantitative measurement (using the anti-Factor Xa method) and qualitative measurement (using prothrombin time, expressed in seconds) are discussed, together with some practical considerations when performing these tests and interpreting the test results.

Clinical performance of bleeding risk scores for predicting major and clinically relevant non-major bleeding events in patients receiving warfarin

BACKGROUND

Oral anticoagulant therapy is associated with an increased risk of hemorrhage, which can be assessed by bleeding risk scores. We evaluated the performance of five validated scores for predicting major and clinically relevant non-major bleeding events in patients receiving warfarin.

METHODS AND RESULTS

We conducted an ambispective, single-center cohort study of 321 consecutive patients enrolled in an academic anticoagulation clinic. The following scores were calculated: modified Outpatient Bleeding Risk Index, Contemporary Bleeding Risk Model, HEMORR(2)HAGES (Hepatic or Renal Disease, Ethanol Abuse, Malignancy, Older Age, Reduced Platelet Count or Function, Re-Bleeding, Hypertension, Anemia, Genetic Factors, Excessive Fall Risk and Stroke), ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation), and HAS-BLED (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile International Normalized Ratio, Elderly, Drugs/Alcohol). Main outcomes were major bleeding and a composite of major plus clinically relevant non-major bleeding. Incidence rates for all group were 3.8 (95% confidence interval [CI] 2.0-6.4) and 11.9 (95% CI 8.6-16.4) events per 100 patient-years for major bleeding and major plus clinically relevant non-major bleeding, respectively. Agreement among the five scores was low to moderate (Kendall's tau-b coefficients 0.22-0.54). For major bleeding, the c-statistics ranged from 0.606 to 0.735, whereas for major plus clinically relevant non-major bleeding, they ranged from 0.549 to 0.613. For all scores, the 95% CI for the c-statistics crossed 0.5 or was very close. Among high-risk patients, the hazard ratios for major bleeding ranged from 0.90 to 39.01, whereas for major plus clinically relevant non-major bleeding, they ranged from 1.52 to 8.71. For intermediate-risk patients, no score, except the Contemporary Bleeding Risk Model, produced statistically significant hazard ratios.

CONCLUSION

The scores demonstrated poor agreement and low to moderate discriminatory ability. General clinical implementation of these scores cannot be recommended yet.