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

Direct oral anticoagulant use in nonvalvular atrial fibrillation with valvular heart disease: a systematic review

Direct oral anticoagulants (DOACs) are indicated for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF), which, according to the American College of Cardiology/American Heart Association/Heart Rhythm Society atrial fibrillation (AF) guidelines, excludes patients with rheumatic mitral stenosis, a mechanical or bioprosthetic heart valve, or mitral valve repair. However, the data regarding use of DOACs in AF patients with other types of valvular heart disease (VHD) are unclear. We aimed to summarize and evaluate the literature regarding the safety and efficacy of DOAC use in NVAF patients with other types of VHD. After an extensive literature search, a total of 1 prospective controlled trial, 4 subanalyses, and 1 abstract were identified. Efficacy of the DOAC agents in NVAF patients with VHD mirrored the overall trial results. Bleeding risk was significantly increased in VHD patients treated with rivaroxaban, but not for dabigatran or apixaban. Of the bioprosthetic valve patients enrolled in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial, no safety or efficacy concerns were identified. In conclusion, subanalyses of DOAC landmark AF trials revealed that dabigatran, rivaroxaban, and apixaban may be safely used in AF patients with certain types of VHD: aortic stenosis, aortic regurgitation, and mitral regurgitation. More evidence is needed before routinely recommending these agents for patients with bioprosthetic valves or mild mitral stenosis. Patients with moderate to severe mitral stenosis or mechanical valves should continue to receive warfarin, as these patients were excluded from all landmark AF trials.

New oral anticoagulants and dual antiplatelet therapy: Focus on apixaban

The combination of AF and coronary artery disease not only is a common clinical setting, it is also a complex setting to deal with anticoagulation and antiplatelet therapy, and it is associated with significantly higher mortality rates. Unfortunately, there are no sufficient data available to optimally guide clinical practice in such settings. This review focuses specifically on newer oral anticoagulants (NOACs) associated with dual antiplatelet therapy (DAPT) in patients with coronary artery disease undergoing percutaneous coronary intervention (PCI). There are no randomized studies comparing vitamin K antagonists and NOACs in patients with AF undergoing PCI either for acute coronary syndromes or for stable patients, i.e. those patients who have an indication to receive DAPT. Moreover, new antiplatelet agents such as ticagrelor and prasugrel have entered the market for acute coronary syndromes. So far, there are no large-scale randomized studies published evaluating these newer antiplatelet agents in patients with AF receiving either vitamin K antagonists or NOACs, adding to the uncertainty on how to use these antithrombotics in combination when both coronary artery disease (unstable or stable patients) and AF converge in a given patient. The lack of large outcome trials and the large number of possible combinations are reflected in the wide variety of practices in the real world. To date, given the lack of data, watchfulness when using NOACs as component of DAPT or triple oral antithrombotic therapy is warranted.

Effectiveness and Safety of an Independently Run Nurse Practitioner Outpatient Cardioversion Program (2009 to 2014)

Sustained growth in the arrhythmia population at Stanford Health Care led to an independent nurse practitioner-run outpatient direct current cardioversion (DCCV) program in 2012. DCCVs performed by a medical doctor, a nurse practitioner under supervision, or nurse practitioners from 2009 to 2014 were compared for safety and efficacy. A retrospective review of the electronic medical records system (Epic) was performed on biodemographic data, cardiovascular risk factors, medication history, procedural data, and DCCV outcomes. A total of 869 DCCVs were performed on 557 outpatients. Subjects were largely men with an average age of 65 years; 1/3 were obese; most had atrial fibrillation; and majority of subjects were on warfarin. The success rate of the DCCVs was 93.4% (812 of 869) with no differences among the groups. There were no short-term complications: stroke, myocardial infarction, or death. The length of stay was shortest in the NP group compared to the other groups (p <0.001). In conclusion, the success rate of DCCV in all groups was extremely high, and there were no complications in any of the DCCV groups.

Anticoagulation Therapy Considerations in Factor VII Deficiency

Factor VII (FVII) deficiency is the most prevalent rare bleeding disorder in the USA and affects approximately 1 out of every 500,000 people. Warfarin inhibits the synthesis of FVII, in addition to other clotting factors. Warfarin is contraindicated in patients with bleeding tendencies or blood dyscrasias; therefore, the literature regarding the use of warfarin in FVII deficiency is very limited. We report a successful re-challenge of warfarin therapy in a patient with FVII deficiency. A 70-year-old woman with FVII deficiency experienced a significant decrease in FVII activity and subsequent vaginal bleeding roughly 5 weeks after starting warfarin for atrial fibrillation. The patient was switched to aspirin therapy. Nearly 4 years later, warfarin therapy was re-attempted by a different haematologist. After 9 months, FVII activity remained in an acceptable range and no bleeding events had occurred. In addition, once the maintenance dose was established, the international normalized ratio remained within the goal range (1.5-2.0) for the majority of assessments. Regarding future considerations, we hypothesize that anticoagulants that do not directly affect FVII, such as the direct oral anticoagulants, would carry less risk of bleeding complications and therefore may be safer alternatives to warfarin to reduce the risk of thromboembolic stroke in patients with atrial fibrillation and FVII deficiency.

Stroke Prevention in Atrial Fibrillation: Focus on Latin America

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with an estimated prevalence of 1-2% in North America and Europe. The increased prevalence of AF in Latin America is associated with an ageing general population, along with poor control of key risk factors, including hypertension. As a result, stroke prevalence and associated mortality have increased dramatically in the region. Therefore, the need for effective anticoagulation strategies in Latin America is clear. The aim of this review is to provide a contemporary overview of anticoagulants for stroke prevention. The use of vitamin K antagonists (VKAs, eg, warfarin) and aspirin in the prevention of stroke in patients with AF in Latin America remains common, although around one fifth of all AF patients receive no anticoagulation. Warfarin use is complicated by a lack of access to effective monitoring services coupled with an unpredictable pharmacokinetic profile. The overuse of aspirin is associated with significant bleeding risks and reduced efficacy for stroke prevention in this patient group. The non-VKA oral anticoagulants (NOACbs) represent a potential means of overcoming many limitations associated with VKA and aspirin use, including a reduction in the need for monitoring and a reduced risk of hemorrhagic events. The ultimate decision of which anticoagulant drug to utilize in AF patients depends on a multitude of factors. More research is needed to appreciate the impact of these factors in the Latin American population and thereby reduce the burden of AF-associated stroke in this region.

Comparative effectiveness and safety of oral anticoagulants for atrial fibrillation in real-world practice: a population-based cohort study protocol

INTRODUCTION

Anticoagulants are arguably the most important drug family of all, based on the frequency and duration of their use, and the clinical importance and frequency of benefits and harms. Several direct acting oral anticoagulants (DOACs) have recently joined warfarin for the treatment of atrial fibrillation, with a resultant significant expansion in use of oral anticoagulants (OACs). Our objectives are to compare safety and effectiveness of DOACs versus warfarin in a full population where anticoagulation management is good and to identify which types of patients do better with DOACs versus warfarin and vice versa.

METHODS AND ANALYSIS

This is a retrospective cohort study of all adults living in British Columbia who have a diagnosis of atrial fibrillation in hospital or medical service data, and a first prescription for an OAC. Coprimary outcomes are ischaemic stroke and systemic embolism (benefit) and major bleeding (harm). Secondary outcomes include net clinical benefit (composite of stroke, systemic embolism, major bleeds, myocardial infarction, pulmonary embolism and death), drug discontinuation and individual composite item occurrence. We will estimate the effects of treatment in a 2-year follow-up period, using time-to-event models with propensity score adjustment to control confounding. Secondary analyses will examine 'as treated' outcomes.

ETHICS AND DISSEMINATION

The protocol, data creation plan, privacy impact statement and data sharing agreements have been approved. Dissemination is planned via conferences and publications as well as directly to drug policy leaders. Information on the overall comparative effectiveness and safety of DOACs versus warfarin in a country with high quality anticoagulation management, as well as for vulnerable subgroups, will be an important addition to the literature.

Selecting antithrombotic therapy for stroke prevention in atrial fibrillation: Health professionals' feedback on a decision support tool

A Computerised Antithrombotic Risk Assessment Tool was developed for assisting the selection of antithrombotic therapy based on the risk versus benefit assessment. In view of the recent availability of the novel oral anticoagulants, this tool has been updated to CARATV2.0. To explore health professionals' perspectives on the tool, semi-structured interviews were conducted in seven pharmacists, seven specialists, six general practitioners and six nurses, who were involved in management of antithrombotic therapy for atrial fibrillation. Three overarching themes emerged: (1) CARATV2.0 provides comprehensive structured assessment of patients and could assist with the prescription and review of antithrombotic therapy, (2) subjective issues such as health professionals' and patients' preferences for a particular antithrombotic therapy may affect the usefulness of CARATV2.0 and (3) CARATV2.0 requires integration into existing systems and processes. The majority of health professionals surveyed would like to use CARATV2.0 in practice, believing it would improve antithrombotic use and might reduce stroke incidence.

Optimising stroke prevention in patients with atrial fibrillation: application of the GRASP-AF audit tool in a UK general practice cohort

BACKGROUND

Oral anticoagulation (OAC) is recommended for effective stroke prevention in the majority of atrial fibrillation patients but is often under-utilised.

AIM

To use the Guidance on Risk Assessment and Stroke Prevention in the Atrial Fibrillation (GRASP-AF) tool to risk stratify patients, identify antithrombotic therapy received, and determine predictors of stroke and death in a UK general practice cohort.

DESIGN AND SETTING

Retrospective-observational cohort study in 11 general practices in Darlington, England, with 105 000 patients.

METHOD

The study included patients with atrial fibrillation (AF) identified from GP databases using the GRASP-AF tool. Stroke risk was determined by CHADS2 and CHA2DS2-VASc scores.

RESULTS

A total of 2259 (2.15%) patients with AF (mean age 76 years [SD 12]; 46% female) were identified. Use of CHA2DS2-VASc rather than CHADS2 increased the proportion eligible for OAC from 86.0% to 92.5%. Of those with CHA2DS2-VASc score of ≥2, 39.7% were not receiving appropriate OAC, and of those with CHADS2 score of ≥1, 39.5% were not receiving appropriate OAC. Antiplatelet monotherapy was utilised in 33-40% of patients at high risk of stroke. During 12-month follow-up, 67 (3.0%) patients experienced a stroke and 214 (9.5%) died. Use of OAC significantly reduced stroke risk (odds ratio [OR] 0.60, 95% confidence intervals [CI] = 0.45 to 0.81) and death (OR = 0.54, 95% CI = 0.38 to 0.75, P<0.001) among patients at moderate-high risk of stroke. Use of antiplatelet agents also independently predicted death (OR = 0.69, 95% CI = 0.50 to 0.94; P = 0.020).

CONCLUSION

Most patients with AF in general practice are at high risk of stroke, but OAC is under-utilised in about 40%. Risk of stroke and death was significantly reduced by OAC, yet antiplatelet monotherapy was inappropriately used in approximately 25% of patients at risk of stroke. Optimal implementation of the CHA2DS2-VASc score in the GRASP-AF tool could help prevent more strokes annually.

Re-Initiation of Dabigatran and Direct Factor Xa Antagonists After a Major Bleed

Direct oral anticoagulants (DOACs) are a relatively recent addition to the oral anticoagulant armamentarium, and provide an alternative to the use of vitamin K antagonists such as warfarin. Regardless of the type of agent used, bleeding is the major complication of anticoagulant therapy. The decision to restart oral anticoagulation following a major hemorrhage in a previously anticoagulated patient is supported largely by retrospective studies rather than randomized clinical trials (mostly with vitamin K antagonists), and remains an issue of individualized clinical assessment: the patient's risk of thromboembolism must be balanced with the risk of recurrent major bleeding. This review provides guidance for clinicians regarding if and when a patient should be re-initiated on DOAC therapy following a major hemorrhage, based on the existing evidence.

Appropriateness of Apixaban Dosing to Prevent Stroke in Patients with Atrial Fibrillation: A Pilot Study

BACKGROUND

The ARISTOTLE study investigated apixaban, at a dose of 5 mg PO bid, for the prevention of stroke in patients with atrial fibrillation; however, it has been noted anecdotally that many patients are receiving 2.5 mg PO bid, despite being eligible for the full dosage. A recent study examining the use of dabigatran and rivaroxaban found that many patients were receiving these medications inappropriately; however, a literature search conducted in April 2016 showed that apixaban had not been formally studied in this context.

OBJECTIVE

To evaluate the appropriateness of apixaban dosing for stroke prevention in patients with atrial fibrillation, relative to the dose used in the ARISTOTLE study and recommendations in the product monograph.

METHODS

This retrospective chart review was conducted at a 300-bed Canadian teaching hospital. All inpatients with atrial fibrillation for whom apixaban was prescribed for stroke prevention in March 2015 were considered for inclusion. The appropriateness of apixaban dosing was determined in relation to the ARISTOTLE methodology and product monograph recommendations (i.e., 5 mg PO bid, with a lower dosage of 2.5 mg PO bid if warranted on the basis of age, weight, or serum creatinine level).

RESULTS

A total of 47 patients were included, of whom 25 (53%) were receiving apixaban inconsistent with the ARISTOTLE study and the product monograph. Limitations of the current study included small sample size, single-centre setting, and retrospective design, which precluded determination of each prescriber's rationale for dosage choice.

CONCLUSIONS

Pharmacists and physicians should be vigilant in ensuring that patients with atrial fibrillation are receiving the appropriate dosage of apixaban to optimize the risk-benefit ratio of this therapy.

Reasons for and consequences of vitamin K antagonist discontinuation in very elderly patients with non-valvular atrial fibrillation

Essentials Anticoagulation in the elderly is still a challenge and suspension of warfarin is common. This is an observational study reporting reasons and consequences of warfarin suspension. Vascular disease, age, time in therapeutic range, and bleedings are associated with suspension. After suspension for bleeding or frailty, patients remain at high-risk of death or complications.

SUMMARY

Background Anticoagulation in elderly patients with non-valvular atrial fibrillation (NVAF) is still a challenge, and discontinuation of warfarin is common. The aim of this study was to analyze the aspects related to warfarin discontinuation in a real-world population. Methods This was an observational cohort study on very elderly NVAF patients naive to warfarin therapy (VENPAF). The included subjects were aged at least 80 years, and started using warfarin after a diagnosis of NVAF. Warfarin discontinuation was assessed, and the reason reported for discontinuation, the person who decided to stop treatment, subsequent antithrombotic therapy and mortality, ischemic and bleeding events were collected. Results Over a period of 5 years, warfarin was discontinued in 148 of 798 patients. Despite similar CHA2 DS2 -VASc scores, the frequencies of thromboembolic and major bleeding events were significantly higher (P = 0.01 and P = 0.001, respectively) and the time in therapeutic range (TTR) was significantly lower (P < 0.001) in patients who discontinued warfarin. Independent risk factors for warfarin discontinuation were vascular disease (hazard ratio [HR] 2.5, P < 0.001), age ≥ 85 years (HR 1.4, P = 0.04), TTR < 60% (HR 1.8, P = 0.001), and bleeding events (HR 2.3, P < 0.001). The main reasons for warfarin discontinuation were physician-perceived frailty or low life-expectancy (45.9%), bleeding complications (19.6%), and sinus rhythm restoration (16.9%). Event and death rates were very high, especially in frail patients and in those with bleeding complications. Conclusions Warfarin discontinuation is frequent in very elderly patients, and is associated with increased risks of death and adverse events. Identification of elderly patients who are at high risk of bleeding and the poor quality of anticoagulation during warfarin are still unsolved clinical problems.

Short-Term Risk of Bleeding During Heparin Bridging at Initiation of Vitamin K Antagonist Therapy in More Than 90 000 Patients With Nonvalvular Atrial Fibrillation Managed in Outpatient Care

Background

Several studies have recently examined the risks of bleeding and of ischemic stroke and systemic embolism associated with perioperative heparin bridging anticoagulation in patients with nonvalvular atrial fibrillation. However, few studies have investigated bridging risks during vitamin K antagonist initiation in outpatient settings.

Methods and Results

A retrospective cohort study was conducted on individuals starting oral anticoagulation between January 2010 and November 2014 for nonvalvular atrial fibrillation managed in outpatient care and identified from French healthcare insurance. Bleeding and ischemic stroke and systemic embolism events were identified from the hospitalization database. Adjusted hazard ratios with 95% CI were estimated using Cox models during the first and 2 following months of anticoagulation. Of 90 826 individuals, 30% had bridging therapy. A total of 318 (0.35%) cases of bleeding and 151 (0.17%) ischemic stroke and systemic embolism cases were identified during the first month of follow‐up and 231 (0.31%) and 122 (0.16%) during the 2 following months, respectively. At 1 month of follow‐up, the incidence of bleeding was higher in the bridged group compared with the nonbridged group (0.47% versus 0.30%; P<0.001), and this increased risk persisted after adjustment for covariates (hazard ratio=1.60; 95% CI, 1.28–2.01). This difference disappeared after the first month of treatment (0.93; 0.70–1.23). No significant difference in the occurrence of ischemic stroke and systemic embolism was observed either at 1 month of follow‐up or later.

Conclusions

At vitamin K antagonist initiation for nonvalvular atrial fibrillation managed in ambulatory settings, bridging therapy is associated with a higher risk of bleeding and a similar risk of arterial thromboembolism compared with no bridging therapy.

Decision-making about the use of non-vitamin K oral anticoagulant therapies for patients with atrial fibrillation

Until recently, vitamin K antagonists, warfarin being the most commonly used agent in the United States, have been the only oral anticoagulant therapies available to prevent stroke in patients with atrial fibrillation (AF). In the last 5 years four new, non-vitamin K oral anticoagulants, the so-called NOACs or novel oral anticoagulants, have come to market and been approved by the Federal Drug Administration. Despite comparable if not superior efficacy in preventing AF-related stroke, and generally lower risks of major hemorrhage, particularly intracranial bleeding, the uptake of these agents has been slow. A number of barriers stand in the way of the more widespread use of these novel agents. Chief among them is concern about the lack of antidotes or reversal agents. Other concerns include the need for strict medication adherence, since missing even a single dose can lead to a non-anticoagulated state; out-of-pocket costs for patients; the lack of easily available laboratory tests to quantitatively assess the level of anticoagulant activity when these agents are being used; contraindications to use in patients with severe chronic kidney disease; and black-box warnings about the increased risk of thromboembolic events if these agents are discontinued prematurely. Fortunately, a number of reversal agents are in the pipeline. Three reversal agents, idarucizumab, andexanet alfa, and aripazine, have already progressed to human studies and show great promise as either antidotes for specific drugs or as universal reversal agents. The availability of these reversal agents will likely increase the clinical use of the non-vitamin K oral anticoagulants. In light of the many complex and nuanced issues surrounding the choice of an optimal anticoagulant for any AF patient, a patient-centered/shared decision-making approach will be useful.

Edoxaban versus enoxaparin-warfarin in patients undergoing cardioversion of atrial fibrillation (ENSURE-AF): a randomised, open-label, phase 3b trial

BACKGROUND

Edoxaban, an oral factor Xa inhibitor, is non-inferior for prevention of stroke and systemic embolism in patients with atrial fibrillation and is associated with less bleeding than well controlled warfarin therapy. Few safety data about edoxaban in patients undergoing electrical cardioversion are available.

METHODS

We did a multicentre, prospective, randomised, open-label, blinded-endpoint evaluation trial in 19 countries with 239 sites comparing edoxaban 60 mg per day with enoxaparin-warfarin in patients undergoing electrical cardioversion of non-valvular atrial fibrillation. The dose of edoxaban was reduced to 30 mg per day if one or more factors (creatinine clearance 15-50 mL/min, low bodyweight [≤60 kg], or concomitant use of P-glycoprotein inhibitors) were present. Block randomisation (block size four)-stratified by cardioversion approach (transoesophageal echocardiography [TEE] or not), anticoagulant experience, selected edoxaban dose, and region-was done through a voice-web system. The primary efficacy endpoint was a composite of stroke, systemic embolic event, myocardial infarction, and cardiovascular mortality, analysed by intention to treat. The primary safety endpoint was major and clinically relevant non-major (CRNM) bleeding in patients who received at least one dose of study drug. Follow-up was 28 days on study drug after cardioversion plus 30 days to assess safety. This trial is registered with ClinicalTrials.gov, number NCT02072434.

FINDINGS

Between March 25, 2014, and Oct 28, 2015, 2199 patients were enrolled and randomly assigned to receive edoxaban (n=1095) or enoxaparin-warfarin (n=1104). The mean age was 64 years (SD 10·54) and mean CHA₂DS₂-VASc score was 2·6 (SD 1·4). Mean time in therapeutic range on warfarin was 70·8% (SD 27·4). The primary efficacy endpoint occurred in five (<1%) patients in the edoxaban group versus 11 (1%) in the enoxaparin-warfarin group (odds ratio [OR] 0·46, 95% CI 0·12-1·43). The primary safety endpoint occurred in 16 (1%) of 1067 patients given edoxaban versus 11 (1%) of 1082 patients given enoxaparin-warfarin (OR 1·48, 95% CI 0·64-3·55). The results were independent of the TEE-guided strategy and anticoagulation status.

INTERPRETATION

ENSURE-AF is the largest prospective randomised clinical trial of anticoagulation for cardioversion of patients with non-valvular atrial fibrillation. Rates of major and CRNM bleeding and thromboembolism were low in the two treatment groups.

FUNDING

Daiichi Sankyo provided financial support for the study.

Incidence of left atrial abnormalities under treatment with dabigatran, rivaroxaban, and vitamin K antagonists

Background

Non-vitamin K antagonist oral anticoagulants (NOACs) such as dabigatran or rivaroxaban are alternatives to vitamin K antagonists (VKAs) for prevention of stroke and systemic embolism in patients with atrial fibrillation (AF) and atrial flutter (AFL). Incidences of risk factors for left atrium (LA) and left atrial appendage (LAA) thrombus formation, such as dense spontaneous echo contrast (SEC), low LAA velocity (LAAV) <20 cm/s under treatment with dabigatran and rivaroxaban in comparison with VKAs are unknown.

Methods

We studied 306 patients with AF (94 %) and AFL (6 %) undergoing transesophageal echocardiography. Patients received VKAs (n = 138), dabigatran (n = 68), or rivaroxaban (n = 100) for at least 3 weeks prior to investigation. Time in therapeutic range was 67 % for VKA. Mean CHADS₂ score and CHA₂DS₂-VASc score were 1.3 and 2.5, respectively. Left atrial abnormality was defined as either dense SEC, low LAAV <20 cm/s, or thrombus.

Results

Any LA abnormality occurred in 9, 3, and 5 % of patients receiving VKA, dabigatran, and rivaroxaban, respectively. The most frequent abnormality was LAA thrombus (VKA: 4 %, dabigatran: 0 %, rivaroxaban: 2 %) and low LAAV of less than 20 cm/s (VKA: 4 %, dabigatran: 1 %, rivaroxaban: 1 %), followed by dense SEC (VKA: 2 %, dabigatran: 1 %, rivaroxaban: 2 %). Results of uni- and multivariate analyses revealed a numerically lower but not significantly different frequency of any LA abnormality under dabigatran (OR 0.4, 95 % Cl 0.08 − 1.88, p = 0.25) and rivaroxaban (OR 0.65, 95 % Cl 0.22 − 1.98, p = 0.45) compared to VKA.

Conclusion

With respect to the incidence of LA abnormalities, dabigatran and rivaroxaban are not inferior to VKA.

New Oral Anticoagulants in Nonvalvular Atrial Fibrillation

The choice of an oral anticoagulant (OAC) for patients with nonvalvular atrial fibrillation (NVAF) is a major and complex clinical decision taking into account the individual risk-benefit ratio and bearing in mind the chronicity of therapy. This review focuses on the safety and efficacy of new oral anticoagulants (NOACs) compared with conventional vitamin K antagonists (VKA) in patients with NVAF. Current data suggest that NOACs are at least as effective and safe as VKAs for most NVAF subjects. The NOACs do not mandate dietary restrictions and regular pharmacodynamic monitoring, and they seem to have lesser incidence of intracranial or fatal bleeding when compared with VKAs. However, both dabigatran 150 twice daily and rivaroxaban have a slightly higher incidence of gastrointestinal bleeding when compared with VKAs. The article will delineate the current knowledge as well as scientific gaps related to the choice and dosage of anticoagulation regimens for various NVAF subsets and will address certain common clinical scenarios requiring special considerations. The article also addresses the shortcomings of NOACs: lack of therapeutic pharmacokinetic and pharmacodynamic targets, absence of tools to assess compliance and efficacy, rigid and limited dosage options, and absence of effective and inexpensive reversal agents.

Pharmacist Interventions Regarding the Appropriateness of Apixaban, Rivaroxaban, Dabigatran, and Warfarin in a University-Affiliated Outpatient Clinic

Background: Direct oral anticoagulants (DOACs) have become available recently as an alternative to warfarin in appropriate patients. Few studies have been conducted that evaluate pharmacist-managed services for the management of the DOACs. Objective: To review the appropriateness of DOAC therapy and warfarin therapy in adult patients in a university-affiliated outpatient clinic and the need for further monitoring of these agents. Methods: A retrospective chart review was conducted of patients receiving a DOAC or warfarin therapy. Indication, dose, duration, age, weight, adherence, drug interactions, bleeding risk/history, renal function, and hepatic function were evaluated for DOACs and warfarin. If prescribed warfarin, international normalized ratio readings were also obtained. The pharmacists made verbal recommendations to primary care prescribers regarding findings, and changes to therapy were reviewed and documented. Results: A total of 175 patient charts were reviewed (49% DOACs, 51% warfarin). Twenty-five percent of prescribed DOACs should have been avoided due to inappropriate indication or renal function. The majority of these were switched to warfarin after discussion with the primary care provider. Of patients prescribed DOACs, 22% had a history of poor adherence to therapy and half of these were switched to warfarin. An additional 24% of prescribed DOACs were inappropriate due to incorrect dosing, major drug interactions, and/or renal dosing; however, these medications could be appropriate if adjustments are made. Nineteen percent of patients on warfarin therapy would be a candidate for DOAC therapy. Conclusion: Although there were limitations to this analysis, the results demonstrate that additional intervention is needed to improve appropriate prescribing and monitoring of the DOACs. Pharmacists can meet this need by providing medication reviews of novel anticoagulants and educating physicians.

Efficacy and Safety of Non-Vitamin K Antagonist Oral Anticoagulants After Cardioversion for Nonvalvular Atrial Fibrillation

BACKGROUND

Non-vitamin K oral anticoagulants (NOACs) are proven alternatives to vitamin K antagonists (VKAs) for the prevention of thromboembolism in patients with nonvalvular atrial fibrillation. However, there are few data on the efficacy and safety of NOAC therapy after cardioversion, where the risk of thromboembolic events is heightened.

METHODS

We performed a random-effects meta-analysis of patients who underwent both electrical and pharmacologic cardioversion for atrial fibrillation in the RE-LY, ROCKET-AF, ARISTOTLE, ENGAGE AF-TIMI 48, and X-VeRT trials. We assessed Mantel-Haenszel pooled estimates of risk ratio (RR) and 95% confidence intervals (CIs) for stroke/systemic embolism and major bleeding at ≤42 days of follow-up.

RESULTS

The analysis pooled 3949 patients in whom a total of 4900 cardioversions for atrial fibrillation were performed. Compared with VKAs, NOAC therapy was associated with a similar risk of stroke/systemic embolism (RR 0.84; 95% CI, 0.34-2.04) and major bleeding (RR 1.12; 95% CI, 0.52-2.42); no significant statistical heterogeneity was found among studies (Cochrane Q P = .59, I(2) = 0% for stroke/systemic embolism; P = .47; I(2) = 0% for major bleeding).

CONCLUSIONS

The short-term incidences of thromboembolic and major hemorrhagic events after cardioversion on NOACs were low and comparable to those observed on dose-adjusted VKA therapy. Non-vitamin K oral anticoagulants are a reasonable alternative to VKAs in patients undergoing cardioversion.

Impact of CHA2DS2VASc Score on Candidacy for Anticoagulation in Patients With Atrial Fibrillation: A Multi-payer Analysis

PURPOSE

The purpose of this study is to report on the effect of using CHA₂DS₂VASc (congestive heart failure, hypertension, age ≥75 years [doubled], type 1 or type 2 diabetes mellitus, stroke or transient ischemic attack or thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease, or aortic plaque], age 65-75 years, sex category [female]) rather than CHADS₂ (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and prior stroke) to determine candidacy for anticoagulant prophylaxis in insured patients with atrial fibrillation (AF).

METHODS

Six administrative claims databases that included medical and pharmacy claims for patients aged ≥18 years with a new or existing diagnosis of AF and patient outcomes assessed for 1 year after diagnosis were analyzed. Retrospective health plan data analyses were performed using a software tool (Anticoagulant Quality Improvement Analyzer). Study measures included stroke risk (identified by CHADS₂ and CHA₂DS₂VASc scores), bleeding risk (identified by the Anticoagulation and Risk Factors in Atrial Fibrillation score), and anticoagulant use.

FINDINGS

A total of 115,906 patients with AF (range of mean ages among the 6 databases, 56-79 years) met the inclusion criteria. All ranges reported represent the minimum and maximum values among the 6 databases. Using the CHA₂DS₂VASc compared with the CHADS₂ index to assess stroke risk resulted in a 23% to 32% increase in patients considered potential candidates for anticoagulant prophylaxis. This translated to a 38% to 114% increase in the number of ostensibly undertreated patients. Among patients with high stroke and low bleeding risk, 18% to 28% more patients were considered potential candidates for anticoagulation treatment using CHA₂DS₂VASc compared with CHADS₂, or a 57% to 151% increase in the number of undertreated patients.

IMPLICATIONS

Use of the CHA₂DS₂VASc score to determine the risk of stroke increased the number of AF patients for whom oral anticoagulation would be recommended. Additional research is needed to determine whether this paradigm shift to greater use of oral anticoagulants improves patient outcomes.

Re-initiation of dabigatran and direct factor Xa antagonists after a major bleed

Direct oral anticoagulants (DOACs) are a relatively recent addition to the oral anticoagulant armamentarium, and provide an alternative to the use of vitamin K antagonists such as warfarin. Regardless of the type of agent used, bleeding is the major complication of anticoagulant therapy. The decision to restart oral anticoagulation following a major hemorrhage in a previously anticoagulated patient is supported largely by retrospective studies rather than randomized clinical trials (mostly with vitamin K antagonists), and remains an issue of individualized clinical assessment: the patient’s risk of thromboembolism must be balanced with the risk of recurrent major bleeding. This review provides guidance for clinicians regarding if and when a patient should be re-initiated on DOAC therapy following a major hemorrhage, based on the existing evidence.

Evolving antithrombotic treatment patterns for patients with newly diagnosed atrial fibrillation

OBJECTIVE

We studied evolving antithrombotic therapy patterns in patients with newly diagnosed non-valvular atrial fibrillation (AF) and ≥1 additional stroke risk factor between 2010 and 2015.

METHODS

39 670 patients were prospectively enrolled in four sequential cohorts in the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF): cohort C1 (2010-2011), n=5500; C2 (2011-2013), n=11 662; C3 (2013-2014), n=11 462; C4 (2014-2015), n=11 046. Baseline characteristics and antithrombotic therapy initiated at diagnosis were analysed by cohort.

RESULTS

Baseline characteristics were similar across cohorts. Median CHA₂DS₂-VASc (cardiac failure, hypertension, age ≥75 (doubled), diabetes, stroke (doubled)-vascular disease, age 65-74 and sex category (female)) score was 3 in all four cohorts. From C1 to C4, the proportion of patients on anticoagulant (AC) therapy increased by almost 15% (C1 57.4%; C4 71.1%). Use of vitamin K antagonist (VKA)±antiplatelet (AP) (C1 53.2%; C4 34.0%) and AP monotherapy (C1 30.2%; C4 16.6%) declined, while use of non-VKA oral ACs (NOACs)±AP increased (C1 4.2%; C4 37.0%). Most CHA₂DS₂-VASc ≥2 patients received AC, and this proportion increased over time, largely driven by NOAC prescribing. NOACs were more frequently prescribed than VKAs in men, the elderly, patients of Asian ethnicity, those with dementia, or those using non-steroidal anti-inflammatory drugs, and current smokers. VKA use was more common in patients with cardiac, vascular, or renal comorbidities.

CONCLUSIONS

Since NOACs were introduced, there has been an increase in newly diagnosed patients with AF at risk of stroke receiving guideline-recommended therapy, predominantly driven by increased use of NOACs and reduced use of VKA±AP or AP alone.

TRIAL REGISTRATION NUMBER

NCT01090362; Pre-results.

Atrial fibrillation is associated with an increased risk of myocardial infarction: Insights from a meta-analysis

BACKGROUND AND AIMS

The presence of atrial fibrillation (AF) markedly increases the risk of stroke and mortality in patients. Whether AF is a risk factor for myocardial infarction (MI) is discrepant from current studies. The aim of this meta-analysis was to ascertain the association of AF with incident MI.

METHODS

Studies were identified through PubMed, CENTRAL, EMBASE, reviews and reference lists of relevant papers. Results of the MI outcome were presented as hazard ratio (HR) and 95% confidence interval (CI). Statistical analyses were performed with Stata 12.0 (Stata Corp LP, College Station, Texas, USA).

RESULTS

Twelve studies, with a total of 169,306 patients, were included in the analysis. AF was associated with a 47% increased risk of MI (HR:1.47; 95% CI: 1.21-1.80; p = 0.000; I² = 84.1%), while in patients free of coronary heart disease at baseline the risk could be increased by 71% (HR:1.71; 95% CI: 1.36-2.14; p = 0.000; I² = 83.1%). Moreover, patients with AF had higher MI risk in the studies with lower mean age (<60 years) (HR:1.66; 95% CI: 1.26-2.20; p = 0.000; I² = 82.9%) than in the studies with higher mean age (≥60 years) (HR:1.35; 95% CI: 1.00-1.82; p = 0.000; I² = 84.9%). Sex difference also existed, and the association between AF and MI was stronger in women (HR:2.02; 95% CI: 1.60-2.56; p = 0.017; I² = 61.0%) than in men (HR:1.44; 95% CI: 1.13-1.84; p = 0.000; I² = 76.1%).

CONCLUSIONS

AF is associated with an increased risk of incident MI, especially in patients free of coronary heart disease at baseline, young patients and women. The findings need confirmation in well-designed observational trials.

Secondary Stroke Prevention: Improving Diagnosis and Management with Newer Technologies

Treatment of hypertension, diabetes, high cholesterol, smoking cessation, and healthy lifestyle have all contributed to the decline in the incidence of vascular disease over the last several decades. Patients who suffer an acute stroke are at a high risk for recurrence. Introduction of newer technologies and their wider use allows for better identification of patients in whom the risk of recurrence following an acute stroke may be very high. Traditionally, the major focus for diagnosis and management has focused on patient history, examination, imaging for carotid stenosis/occlusion, and detection of AF and paroxysmal AF (PAF) with 24-48 h cardiac monitoring. This review focuses on the usefulness of three newer investigative tools that are becoming widely available and lead to better prevention. Continuous ambulatory blood pressure measurements for 24 h or longer and 3D Doppler measures of the carotid arteries provide key useful information on the state of vascular health and enhance our ability to monitor the response to preventive therapies. Furthermore, the detection of PAF can be significantly improved with prolonged cardiac monitoring for 3 weeks or longer, enabling the initiation of appropriate prevention therapy. This review will focus on the potential impact and importance of these emerging technologies on the prevention of recurrent stroke in high-risk patients.

Clinical management and outcome of major bleeding in patients on treatment with vitamin K antagonists

BACKGROUND

The optimal management of major bleeding associated with vitamin K antagonists remains unclear.

OBJECTIVES

The aim of the study was to assess the determinants of outcome of vitamin K antagonists-associated major bleeding and the outcome of bleeding in relation with the therapeutic management.

METHODS

Patients hospitalized for major bleeding while on vitamin K antagonists were included in a prospective, cohort study. Major bleeding was defined according to the criteria of the International Society of Thrombosis Haemostasis. The primary study outcome was death at 30days from major bleeding.

RESULTS

544 patients were included in this study, of which 282 with intracranial hemorrhage. Prothrombin complex concentrates were used in 51% and in 23% of patients with intracranial hemorrhage or non-intracranial major bleeding, respectively (p<0.001); fresh frozen plasma was used in 7% and in 17% of patients with intracranial hemorrhage or non-intracranial major bleeding (p<0.001). Death at 30days occurred in 100 patients (18%), 72 patients with intracranial hemorrhage and 28 patients with non-intracranial major bleeding. Age over 85years, low Glasgow Coma Scale score and shock were independent predictors of death at 30days. Invasive procedures were associated with decreased risk of death.

CONCLUSIONS

Among the patients hospitalized for major bleeding while on vitamin K antagonists, the risk for death is substantial. The risk for death is associated with the clinical severity of major bleeding as assessed by the GCS score and by the presence of shock more than with the initial localization of major bleeding (ICH vs other sites).

Apixaban compared with parenteral heparin and/or vitamin K antagonist in patients with nonvalvular atrial fibrillation undergoing cardioversion: Rationale and design of the EMANATE trial

BACKGROUND

Stroke prevention in anticoagulation-naïve patients with atrial fibrillation undergoing cardioversion has not been systematically studied.

OBJECTIVE

To determine outcomes in anticoagulation-naïve patients (defined as those receiving an anticoagulant for <48 hours during the index episode of atrial fibrillation) scheduled for cardioversion.

METHODS

This is a randomized, prospective, open-label, real-world study comparing apixaban to heparin plus warfarin. Early image-guided cardioversion is encouraged. For apixaban, the usual dose is 5 mg BID with a dose reduction to 2.5 mg BID if 2 of the following are present: age >80 years, weight <60 kg, or serum creatinine >1.5 mg/dL. If cardioversion is immediate, a single starting dose of 10 mg (or 5 mg if the dose is down-titrated) of apixaban is administered. Cardioversion may be attempted up to 90 days after randomization. Patients are followed up for 30 days after cardioversion or 90 days postrandomization if cardioversion is not performed within that timeframe. Outcomes are stroke, systemic embolization, major bleeds, clinically relevant nonmajor bleeding, and death, all adjudication-blinded.

STATISTICS

The warfarin-naive cohort from the ARISTOTLE study was considered the closest data set to the patients being recruited into this study. The predicted incidence of stroke, systemic embolism, and major bleeding within 30 days after randomization was approximately 0.75%. To adequately power for a noninferiority trial, approximately 48,000 participants would be needed, a number in excess of feasibility. The figure of 1,500 patients was considered clinically meaningful and achievable.

CLINICAL CONTEXT

This first prospective cardioversion study of a novel anticoagulant in anticoagulation-naïve patients should influence clinical practice.

Trends in antithrombotic therapy for atrial fibrillation: Data from the Veterans Health Administration Health System

BACKGROUND

Although controversial, several prior studies have suggested that oral anticoagulants (OACs) are underused in the US atrial fibrillation (AF) population. Appropriate use of OACs is essential because they significantly reduce the risk of stroke in those with AF. In the >2 million Americans with AF, OACs are recommended when the risk of stroke is moderate or high but not when the risk of stroke is low. To quantify trends and guideline adherence, we evaluated OAC use (either warfarin or dabigatran) in a 10-year period in patients with new AF in the Veterans Health Administration.

METHODS

New AF was defined as at least 2 clinical encounters documenting AF within 120 days of each other and no previous AF diagnosis (N = 297,611). Congestive Heart Failure, Hypertension, Age > 75, Diabetes, and Stroke (CHADS2) scores were determined using age and diagnoses of hypertension, diabetes, heart failure, and stroke or transient ischemic attack during the 12 months before AF diagnosis. Receipt of an OAC within 90 days of a new diagnosis of AF was evaluated using VA pharmacy data.

RESULTS

Overall, initiation of an OAC fell from 51.3% in 2002 to 43.1% in 2011. For patients with CHADS2 score of 0, 1, 2, 3, 4, and 5-6, the proportions of patients prescribed an OAC showed a relative decrease of 26%, 23%, 14%, 12%, 9%, and 13%, respectively (P < .001). Clopidogrel use was stable at 10% of the AF population.

CONCLUSIONS

Among US veterans with new AF and additional risk factors for stroke, only about half receive OAC, and the proportion is declining.

Validation Of The HAS-BLED Tool In Atrial Fibrillation Patients Receiving Rivaroxaban

Background: Atrial fibrillation (Afib) patients are at an increased risk of stroke. Patients at moderate to high risk of stroke typically receive antithrombotics, placing them at an increased risk of bleeding. The HAS-BLED tool has been validated in Afib patients receiving warfarin for prediction of major bleeding events. Although HAS-BLED has been researched in patients receiving warfarin, this tool has not been validated with the novel anticoagulant rivaroxaban. Methods: The trial design was retrospective case-control approved by the Institutional Review Board at University of Tennessee Medical Center. Patients who were identified as having a bleeding event were cross-referenced with a list of patients receiving rivaroxaban. Inclusion criteria were adult patients with atrial fibrillation who were taking rivaroxaban for at least six months, with a CHA₂DS₂-VASc score greater than or equal to 2 OR CHADS₂ score greater than or equal to 1. The primary endpoint is the predictive ability of HAS-BLED as measured through the c-statistic. Secondary endpoints include correlation of HAS-BLED and bleeding risk. Results: After reviewing 9621 medical records, 15 patients met the inclusion criteria for major bleeding. Ninety patients were randomly selected for inclusion as the matched control group. The predictive ability of HAS-BLED was not statistically significant (c statistic = 0.68; p = 0.07), but did show some diagnostic ability to predict major bleeding events. Patients with major bleeding were more likely to have a history of bleeding and use concomitant antiplatelet agents. There were significantly more patients with a HAS-BLED score greater than or equal to 3 in the patients that experienced a major bleeding event. Conclusion: HAS-BLED demonstrated some diagnostic ability to predict major bleeding events in patients receiving rivaroxaban but this was not statistically significant due to limited sample size.

Antithrombotic Usage Patterns in the Era of New Oral Anticoagulant Options for Atrial Fibrillation

BACKGROUND

Appropriate treatment reduces the risk of stroke in patients with atrial fibrillation (AF). Despite the known benefits of warfarin, anticoagulation prescribing rates remain inadequate in high-risk patients. Over the last 6 years, 4 novel oral anticoagulants have been approved for use for stroke prophylaxis in non-valvular AF (NVAF), which may allow prescribers to tailor therapy for each NVAF patient.

OBJECTIVE

The goal of this investigation was to determine the effect of dabigatran and rivaroxaban availability on the rate of anticoagulant prescribing at hospital discharge in patients with a principal diagnosis of NVAF.

METHODS

A retrospective chart review of adult patients presenting with NVAF (CHADS2 score ≥2) was conducted using a historical control group of patients from 2009 compared to patients admitted in 2012 following formulary availability of dabigatran and rivaroxaban. In addition to antithrombotic therapy prescribed, subsequent hospitalizations during a 1-year period were reviewed for major bleeding and stroke events.

RESULTS

Two hundred patients were enrolled in the study. The rate of anticoagulant prescribing in the 2009 and 2012 groups was 68.3% and 77.1%, respectively (p = .16). Of the patients in the 2012 group prescribed an anticoagulant, 58 (64%) received warfarin, 26 (28%) received dabigatran, and 7 (8%) received rivaroxaban. One patient (1.2%) in the 2009 group and 4 patients (4.4%) in the 2012 group had a major bleed (p = .4).

CONCLUSION

There was no statistical difference in the rate of anticoagulant prescribing between the 2 groups. Despite the availability of additional anticoagulant options, the rate of prescribing remains suboptimal in this high-risk population.

Anticoagulated patient's perception of their illness, their beliefs about the anticoagulant therapy prescribed and the relationship with adherence: impact of novel oral anticoagulant therapy - study protocol for The Switching Study: a prospective cohort study

Background

Anticoagulant therapy is prescribed for millions of patients worldwide for the prevention and treatment of both arterial and venous thrombosis. Historically, only vitamin K antagonists have been available for clinicians to prescribe. The anticoagulation landscape is changing. The recent availability of the novel oral anticoagulants overcome many of the disadvantages associated with vitamin K antagonists. However the lack of formal monitoring and clinic follow-up is a concern for clinicians, as medication adherence is being assumed, which is known to decline in patients prescribed medications for chronic conditions. The switching study is a programme of work investigating the association between medication adherence and patient’s beliefs about anticoagulation therapy (warfarin and subsequently novel oral anticoagulants), together with beliefs about their illness and anticoagulation related quality of life.

Methods/design

The anticoagulation database at King’s College Hospital will be interrogated and two groups of patients will be identified; those with a time in therapeutic range on warfarin of ≥75 % and those <50 %. These groups of patients will have their illness perceptions, anticoagulation specific quality of life and beliefs about medications compared. Those patients in the time in therapeutic range <50 % group, will be then be invited to switch to a novel oral anticoagulant, as per local guidance. Those patients, who do switch, will then be followed longitudinally and have their adherence, illness perceptions, anticoagulation specific quality of life and beliefs about medications, re-evaluated on the novel agent. The results from these sub-studies, will inform a clinical pathway to support patients on these novel agents, which will be evaluated in an independent group of patients.

Discussion

The results from the switching study will be used to develop a clinical pathway to support patient’s prescribed novel oral anticoagulant therapy long-term.

Electronic supplementary material

The online version of this article (doi:10.1186/s12878-016-0061-9) contains supplementary material, which is available to authorized users.

A Comparison Between NOACs and Warfarin on Time to Elective Cardioversion

Cardioversion of atrial fibrillation is a procedure that has been commonly performed for over half a century. There is known to be an elevated risk of thromboembolism around the time of cardioversion, which has been shown to be drastically reduced with oral anticoagulation. The consistency of therapeutic anticoagulation in the weeks leading up to elective cardioversion is an important factor in the safety of the procedure. Until recently, the only option for oral anti-coagulation was Warfarin. The challenges of dosing Warfarin to achieve a therapeutic INR are well documented. In recent years, novel oral anticoagulant medications have been developed, which are thought to provide a consistent intensity of anticoagulation and do not require routine monitoring or dose adjustment. The purpose of this review is to examine the literature pertaining to a comparison of Warfarin versus novel oral anti-coagulants with respect to time of elective cardioversion.

Adjuvant Chinese Herbal Products for Preventing Ischemic Stroke in Patients with Atrial Fibrillation

OBJECTIVE

Chinese herbal products (CHPs) are widely used for atrial fibrillation (AF) in Taiwan. We investigated the effect of adjuvant CHPs in preventing ischemic stroke in patients with AF.

METHODS

Taiwanese patients in the Health Insurance Database newly diagnosed with AF during 2000-2011 were enrolled. Medication treatment with/without CHPs was administered within 7 days after the AF diagnosis. The clinical endpoint was an ischemic stroke. The Chi-square test, Fisher's exact test, and Student t test were used to examine differences between the traditional Chinese medicine (TCM) and non-TCM cohorts. Cox proportional hazard regression was used to assess the risk for ischemic stroke between two cohorts.

RESULTS

Three hundred and eleven patients underwent TCM treatment and 1715 patients did not. Compared to non-TCM users, TCM users had a lower incidence of stroke (12.59% vs. 1.93%, respectively) and lower risk of stroke [CHA2DS2-VASc score = 0-2 (hazard ratio = 0.20; 95% confidence interval = 0.06-0.65)]. Compared to non-TCM users, the stroke risk was significantly lower in TCM users with AF who were female or younger than 65 years, but not in males, people more than 65 years old, or people with comorbidities. Compared to TCM users, non-TCM users who received conventional treatment had a higher ischemic stroke risk. The risk for AF-related hospitalization was significantly lower in TCM users (0.64%) than in non-TCM users (38.1%).

CONCLUSIONS

Users of TCM with AF have a lower risk of new-onset ischemic stroke. Therefore, adjuvant CHP therapy may have a protective effect and may be used in AF patients to prevent ischemic stroke.

Direct oral anticoagulants: unique properties and practical approaches to management

Since 2009, four direct oral anticoagulants (DOACs) have been introduced for treatment of venous thromboembolism and stroke prevention in non-valvular atrial fibrillation. While they are currently first-line therapy for a majority of patients, there are a number of clinical situations where warfarin is preferable. In both randomised trials and real-world populations, use of DOACs significantly reduces the risk of intracranial haemorrhage as compared with warfarin. While drug-specific reversal agents are currently only available for dabigatran, andexanet alpha is pending approval for reversal of factor Xa inhibitors, reducing concerns about major bleeding for many patients and providers. DOACs can be held for 2-4 days prior to a procedure, depending on a patient's renal function, but should not be restarted too rapidly post-procedurally given their fast time to peak activity (∼2 hours). The anticoagulation clinic should play an important role in managing patients on all oral anticoagulation, both warfarin and DOACs.

Practical Considerations for the Use of Direct Oral Anticoagulants in Patients With Atrial Fibrillation

Atrial fibrillation (AF) is a significant risk factor for stroke and peripheral thromboembolic events (TEs). Preventing blood clots in the heart to reduce stroke and TE risk is a key goal of AF therapy. Traditional stroke risk assessment tools for patients with nonvalvular AF include the CHADS2 and CHA(2)DS(2)-VASc scores, while long-term outcome data with the newer direct oral anticoagulants (DOACs) are emerging. The goals of this review were to assess traditional therapies and existing treatment guidelines and to discuss key pharmacologic properties of the DOACS, noting how these may benefit at-risk patients with AF. This narrative review was developed on the basis of the authors’ clinical knowledge, extensive reading of the literature, and broad pharmacy experience in the management of patients with AF. Limitations of oral vitamin K antagonists (VKAs) include slow onset of action, the need for regular monitoring of their anticoagulation effect, significant food and drug interactions, and unpredictable dose–response properties. Key clinical trial data led to the approvals of apixaban, dabigatran etexilate, edoxaban, and rivaroxaban in the United States to reduce the risk of stroke and systemic embolism in patients with nonvalvular AF. With predictable pharmacologic properties and limited drug and/or dietary interactions, the DOACs offer several benefits over traditional oral anticoagulation therapy with VKA. However, they have limitations, including the absence of immediate reversal agents and limited options for monitoring their anticoagulation effects in clinical practice. As experience with the use of DOACs grows, optimized treatment regimens and improved patient care are expected.

The Utilization of Antithrombotic Therapy in Older Australians With Atrial Fibrillation

What is known and Objective:

Oral anticoagulants are essential drugs for the prevention of thromboembolic events in patients with atrial fibrillation (AF). Anticoagulants are, however, commonly withheld due to a perceived risk of severe adverse events. The underutilization of anticoagulants in patients with AF has been demonstrated internationally, but to date, there are limited data available in the Australian context. The aim of this study was to determine the utilization patterns of anticoagulants (including novel oral anticoagulants) with respect to stroke and bleeding risk among patients with AF within the community.

Methods:

We performed a nonexperimental, retrospective analysis designed to evaluate antithrombotic usage for AF in Australia. The utilization of antithrombotic therapy and the appropriateness of therapy were determined based on CHADS2, CHA2DS2-VASc and HAS-BLED risk stratification schemes. The presence of documented contraindications was used to determine the appropriateness of antithrombotic therapy.

What is new and Conclusion:

Anticoagulants were overutilized in patients at low risk of stroke and underutilized in patients at higher risk of stroke. As the HAS-BLED score increased, the likelihood of patients receiving an anticoagulant decreased regardless of CHADS2 or CHA2DS2-VASc scores.

The Role Of NOACs in Atrial Fibrillation Management: A Qualitative Study

Patients with atrial fibrillation (AF) benefit from anticoagulation to reduce stroke risk. However, 30-60% of patients with AF are not anticoagulated. This study explored physicians' reasons for under-treatment of AF, focusing on the role of the novel oral anticoagulants (NOACs). We interviewed primary care physicians and cardiologists involved in AF management in a variety of practice settings. We conducted interviews using a semi-structured format and analyzed the data using the Framework Method. Four themes emerged. First, the likelihood of physicians to prescribe NOACs depends upon their willingness to try new medications and their successful experience with them. Second, physicians typically balance the benefits and risks of anticoagulation in AF patients, although not always accurately. Third, patient convenience and preferences, as well as physician convenience, are important when considering anticoagulation. Finally, concerns regarding the out-of-pocket cost of NOACs deter many physicians from prescribing them. The persistence of under-treatment in AF despite the availability of effective therapies suggests that new strategies are needed to improve physician knowledge and practice. These strategies should enhance physician awareness of AF under-treatment, emphasize accurate assessment of bleeding risk among AF patients, compare the safety, efficacy, and convenience of NOACs relative to warfarin, and address physician concerns regarding the out-of-pocket cost of NOACs. Guidelines and decision supports which promote physician knowledge in these areas have the potential to increase oral anticoagulant use and reduce preventable morbidity and mortality.