Updated European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist anticoagulants in patients with non-valvular atrial fibrillation

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.

Impact of Renal Function on Outcomes With Edoxaban in the ENGAGE AF-TIMI 48 Trial

Background:

Edoxaban, an oral factor Xa inhibitor with 50% renal clearance, was noninferior to well-managed warfarin for stroke or systemic embolism (S/SE) prevention and reduced bleeding in patients with atrial fibrillation. We evaluated the efficacy and safety of edoxaban versus warfarin across the range of baseline creatinine clearance (CrCl) in the ENGAGE AF-TIMI 48 trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation–Thrombolysis in Myocardial Infarction Study 48) with a focus on the higher-dose edoxaban regimen (HDER) and the upper range of CrCl.

Methods:

A total of 14 071 patients with atrial fibrillation at moderate to high risk for stroke were randomized to warfarin or HDER (60 mg daily or a 50% dose reduction to 30 mg daily for CrCl 30–50 mL/min, body weight of ≤60 kg, or use of a potent phosphorylated glycoprotein inhibitor). CrCl <30 mL/min was exclusionary. End points of S/SE, International Society on Thrombosis and Haemostasis major bleeding, and the net clinical outcome of S/SE/major bleeding or death were evaluated by intention-to-treat analysis using the prespecified CrCl cut point of 50 mL/min and additional exploratory cut points with the Cockcroft-Gault formula. A sensitivity analysis was performed with the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula for estimating renal function.

Results:

The relative risk of S/SE with HDER versus warfarin in patients with CrCl >50 mL/min (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.72–1.04) was similar to that in patients with CrCl ≤50 mL/min (HR, 0.87; 95% CI, 0.65–1.18; P for interaction=0.94). Several exploratory analyses suggested lower relative efficacy for the prevention of S/SE with HDER compared with warfarin at higher levels of CrCl (CrCl ≤50 mL/min: HR, 0.87; 95% CI, 0.65–1.18; CrCl >50–95 mL/min: HR, 0.78; 95% CI, 0.64–0.96; CrCl >95 mL/min: HR, 1.36; 95% CI, 0.88–2.10; P for interaction=0.08). Bleeding rates were lower at all levels of CrCl with HDER ( P for interaction=0.11). Because of the preserved effect on bleeding, the net clinical outcome was more favorable with HDER across the range of CrCl ( P for interaction=0.73). Similar findings were observed in the sensitivity analysis using the CKD-EPI formula.

Conclusions:

Although there was an apparent decrease in relative efficacy to prevent arterial thromboembolism in the upper range of CrCl, the safety and net clinical benefit of HDER compared with warfarin are consistent across the range of renal function.

Clinical Trial Registration:

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00781391.

Intravenous Thrombolysis after Reversal of Dabigatran by Idarucizumab: A Case Report

We describe a 75-year-old female patient with nonvalvular atrial fibrillation who presented with acute ischemic stroke during treatment with dabigatran 2 × 110 mg per day. After informed consent, we reversed the anticoagulant effects of dabigatran using idarucizumab and applied an intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator (off-label use). An intracerebral hemorrhage was excluded after systemic thrombolysis. Despite the IVT, the patient's clinical condition deteriorated and she developed an ischemic lesion in the right pons, the right thalamus and right cerebellum. To date, the literature lacks data concerning the thrombolytic treatment of acute ischemic stroke in patients after specific reversal of the non-vitamin K oral anticoagulant dabigatran using idarucizumab. Given the rapid and sustainable efficacy of idarucizumab, the reversal of dabigatran followed by thrombolysis seems to be safe, but further studies and register data are still needed to confirm our preliminary observation, especially to provide additional data concerning the risk-benefit evaluation.

Dabigatran approaching the realm of heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a serious, immune mediated complication of exposure to unfractionated or low-molecular-weight heparin. Though rare, it is a condition associated with high morbidity and mortality that requires immediate change to alternative anticoagulants for the prevention of life-threatening thrombosis. The direct thrombin inhibitors lepirudin and argatroban are currently licensed for the treatment of HIT. Dabigatran, a novel oral anticoagulant (NOAC) with a similar mechanism of action and effective use in other indications, has recently been proposed as another therapeutic option in cases of HIT. This review serves as an introduction to using dabigatran for this purpose, detailing the clinical aspects of its administration, evidence of its performance compared to other anticoagulants, and the preliminary reports of HIT successfully treated with dabigatran. As the literature on this develops, it will need to include clinical trials that directly evaluate dabigatran against the other NOACs and current treatment options.

Comparative effectiveness and safety of non-vitamin K antagonist oral anticoagulants and warfarin in patients with atrial fibrillation: propensity weighted nationwide cohort study

OBJECTIVE

 To study the effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (novel oral anticoagulants, NOACs) dabigatran, rivaroxaban, and apixaban compared with warfarin in anticoagulant naïve patients with atrial fibrillation.

DESIGN

 Observational nationwide cohort study.

SETTING

 Three Danish nationwide databases, August 2011 to October 2015.

PARTICIPANTS

 61 678 patients with non-valvular atrial fibrillation who were naïve to oral anticoagulants and had no previous indication for valvular atrial fibrillation or venous thromboembolism. The study population was distributed according to treatment type: warfarin (n=35 436, 57%), dabigatran 150 mg (n=12 701, 21%), rivaroxaban 20 mg (n=7192, 12%), and apixaban 5 mg (n=6349, 10%).

MAIN OUTCOME MEASURES

 Effectiveness outcomes defined a priori were ischaemic stroke; a composite of ischaemic stroke or systemic embolism; death; and a composite of ischaemic stroke, systemic embolism, or death. Safety outcomes were any bleeding, intracranial bleeding, and major bleeding.

RESULTS

 When the analysis was restricted to ischaemic stroke, NOACs were not significantly different from warfarin. During one year follow-up, rivaroxaban was associated with lower annual rates of ischaemic stroke or systemic embolism (3.0% v 3.3%, respectively) compared with warfarin: hazard ratio 0.83 (95% confidence interval 0.69 to 0.99). The hazard ratios for dabigatran and apixaban (2.8% and 4.9% annually, respectively) were non-significant compared with warfarin. The annual risk of death was significantly lower with apixaban (5.2%) and dabigatran (2.7%) (0.65, 0.56 to 0.75 and 0.63, 0.48 to 0.82, respectively) compared with warfarin (8.5%), but not with rivaroxaban (7.7%). For the combined endpoint of any bleeding, annual rates for apixaban (3.3%) and dabigatran (2.4%) were significantly lower than for warfarin (5.0%) (0.62, 0.51 to 0.74). Warfarin and rivaroxaban had comparable annual bleeding rates (5.3%).

CONCLUSION

 All NOACs seem to be safe and effective alternatives to warfarin in a routine care setting. No significant difference was found between NOACs and warfarin for ischaemic stroke. The risks of death, any bleeding, or major bleeding were significantly lower for apixaban and dabigatran compared with warfarin.

Decision-making around antithrombotics for stroke prevention in atrial fibrillation: the health professionals' views

Background For stroke prevention in patients with atrial fibrillation (AF), the decision-making around antithrombotic therapy has been complicated by older age, multiple comorbidities, polypharmacy and the different pharmacological properties of warfarin and the nonvitamin K antagonist oral anticoagulants (NOACs). The complexity of decision-making has been associated with a reluctance by health professionals to use antithrombotic therapy, leading to poor clinical outcomes. In order to improve stroke prevention in patients with AF, the contemporary perspectives of health professionals on the decision-making around antithrombotic therapy needs exploration. Objective To elicit emerging themes describing health professionals' perspectives on the decision-making around antithrombotic therapy for stroke prevention in patients with AF. Setting Sydney metropolitan area of New South Wales, Australia. Method A qualitative study based on face-to-face interviews was conducted from August to October 2014. Seven pharmacists, seven specialists, six general practitioners and six nurses practising in the Sydney metropolitan area and managing antithrombotic therapy for AF were interviewed until theme saturation was achieved in each subgroup. Interview transcripts were analysed using manual inductive coding. Main outcome measure Emerging themes describing health professionals' perspectives on the decision-making around antithrombotic therapy for stroke prevention in patients with AF. Results Three overarching themes emerged. (1) Comprehensive assessment is necessary for decision-making but is not always implemented. Health professionals mostly focused on stroke risk assessment, not on the bleeding risk and medication safety issues. (2) Health professionals from different disciplines have different preferences for antithrombotic therapies. Although the majority of health professionals considered warfarin as the first-line therapy, NOACs were preferred by neurologists and haematologists. (3) Health professionals focused on different aspects of the decision making process: GPs and specialists were concerned about the appropriate prescription of antithrombotics, while pharmacists and nurses focused on daily medication management by patients. Conclusion The decision-making process appears to be partially preference based rather than systematic, and health professionals from various disciplines focus on different parts of the decision-making process.

Resuming anticoagulant therapy after intracerebral bleeding

The clinical benefit of resuming anticoagulant treatment after an anticoagulants-associated intracranial hemorrhage (ICH) is debated. No randomized trial has been conducted on this particular clinical issue. The risk of ICH recurrence from resuming anticoagulant therapy is expected to be higher after index lobar than deep ICH and in patients with not amendable risk factors for ICH. Retrospective studies have recently shown improved survival with resumption of treatment after index anticoagulants-associated ICH. Based on these evidences and on the risk for thromboembolic events without anticoagulant treatment, resumption of anticoagulation should be considered in all patients with mechanical heart valve prosthesis and in those with amendable risk factors for anticoagulants-associated ICH. Resumption with direct oral anticoagulants appears a reasonable option for non-valvular atrial fibrillation (NVAF) patients at moderate to high thromboembolic risk after deep ICH and for selected NVAF patients at high thromboembolic risk after lobar ICH. For VTE patients at high risk for recurrence, resumption of anticoagulation or insertion of vena cava filter should be tailored on the estimated risk for ICH recurrence.

Efficacy and Safety of Edoxaban in Elderly Patients With Atrial Fibrillation in the ENGAGE AF-TIMI 48 Trial

Background

Elderly patients with atrial fibrillation are at higher risk of both ischemic and bleeding events compared to younger patients. In a prespecified analysis from the ENGAGE AF‐TIMI 48 trial, we evaluate clinical outcomes with edoxaban versus warfarin according to age.

Methods and Results

Twenty‐one thousand one‐hundred and five patients enrolled in the ENGAGE AF‐TIMI 48 trial were stratified into 3 prespecified age groups: <65 (n=5497), 65 to 74 (n=7134), and ≥75 (n=8474) years. Older patients were more likely to be female, with lower body weight and reduced creatinine clearance, leading to higher rates of edoxaban dose reduction (10%, 18%, and 41% for the 3 age groups, P<0.001). Stroke or systemic embolic event (1.1%, 1.8%, and 2.3%) and major bleeding (1.8%, 3.3%, and 4.8%) rates with warfarin increased across age groups (P_trend<0.001 for both). There were no interactions between age group and randomized treatment in the primary efficacy and safety outcomes. In the elderly (≥75 years), the rates of stroke/systemic embolic event were similar with edoxaban versus warfarin (hazard ratio 0.83 [0.66–1.04]), while major bleeding was significantly reduced with edoxaban (hazard ratio 0.83 [0.70–0.99]). The absolute risk difference in major bleeding (−82 events/10 000 pt‐yrs) and in intracranial hemorrhage (−73 events/10 000 pt‐yrs) both favored edoxaban over warfarin in older patients.

Conclusions

Age has a greater influence on major bleeding than thromboembolic risk in patients with atrial fibrillation. Given the higher rates of bleeding and death with increasing age, treatment of elderly patients with edoxaban provides an even greater absolute reduction in safety events over warfarin, compared to treatment with edoxaban versus warfarin in younger patients.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00781391.

Spotlight on idarucizumab and its potential for the reversal of anticoagulant effects of dabigatran

Idarucizumab is the first targeted antidote of dabigatran, a direct oral anticoagulant used for prevention and treatment of venous thromboembolism and prevention of stroke in atrial fibrillation. Idarucizumab is a humanized fragment of a monoclonal antibody, which binds dabigatran reversibly with high affinity and, when administered intravenously, immediately neutralizes its anticoagulant effect. It is rapidly cleared by the kidney with captured dabigatran. In Phase I and II trials, no significant adverse events have been reported. Specifically, idarucizumab has no anticoagulant or procoagulant effect by itself. Idarucizumab is currently being evaluated in an ongoing Phase III trial, in patients treated with dabigatran presenting with severe active bleeding or requiring emergency surgery or an invasive procedure and are at high risk of bleeding. The results of the interim analysis confirm the ability of idarucizumab to neutralize dabigatran instantaneously, without rebound effect, except in rare patients with very high baseline levels of anticoagulant. Although not definitely proving clinical efficacy, due to the noncontrolled design of the trial and the heterogeneity of patient conditions, these promising results on an intermediate criterion with strong rationale have led to the approval of idarucizumab for these indications. However, several questions are unresolved. First, activity measurement of dabigatran in blood, useless in current practice, could be useful to guide the treatment and avoid over- or underutilization of the antidote; but so far, it has not been largely available in real time. Second, the translation of anticoagulant neutralization to an effect on mortality and better outcome is highly dependent on the global management of these patients, especially rapid diagnosis, supportive care, and easy access to antidote administration. Although idarucizumab represents a remarkable achievement in drug design and development, whether it will be an important step toward improved safety of patients treated with dabigatran in the real world will have to be demonstrated in the postmarketing phase.

An update on laboratory measurements of Dabigatran: Smart specific and calibrated dedicated assays for measuring anti-IIa activity in plasma

Use of Direct Oral Anticoagulants (DOACs) is continuously increasing for clinical application. The first product released was Dabigatran, which was proposed for many preventive and curative applications, especially for prevention of stroke in patients with non-valvular atrial fibrillation. Although measurement of Dabigatran Anti-IIa activity in plasma is not requested on a routine basis, in some situations its measurement is clinically useful. Especially, before an emergency surgery in treated patients, where its presence at high concentrations, which will expose the patient at an increased bleeding risk, has to be excluded. Hence, smart, specific, rapid and accurate quantitative assays are warranted as an essential required. Hemoclot™ Thrombin Inhibitors and Biophen® DTI were specifically designed for these applications, and can be used on all automated instruments with a standard range protocol for measuring concentrations at peak, or with a low range protocol for testing residual concentrations. Both functional assays have a good correlation with the reference LC-MS/MS method, and concentrations measured are similar. Performances of these assays and interferences of various substances or drugs are discussed. Some differences in variations of clotting times are observed between mechanical or optical clot detection instruments, which could be explained by the fibrin clot structure, altered by direct Factor Xa inhibitors, and more especially Rivaroxaban. Both clotting and chromogenic assays offer a safe and accurate quantitative measurement of Dabigatran in plasma in all situations where this determination is requested. In short this manuscript provides an in depth update on current opinions on laboratory aspects of measuring Dabigatran concentrations in plasma, when required.

Effective management of venous thromboembolism in the community: non-vitamin K antagonist oral anticoagulants

Anticoagulation therapy is essential for the effective treatment and secondary prevention of venous thromboembolism (VTE). For many years, anticoagulation for acute VTE was limited to the use of initial parenteral heparin, overlapping with and followed by a vitamin K antagonist. Although highly effective, this regimen has several limitations and is particularly challenging when given in an ambulatory setting. Current treatment pathways for most patients with deep-vein thrombosis typically involve initial hospital or community-based ambulatory care with subsequent follow-up in a secondary care setting. With the introduction of non-vitamin K antagonist oral anticoagulants (NOACs) into routine clinical practice, it is now possible for the initial acute management of patients with deep-vein thrombosis to be undertaken by primary care. As hospital admissions associated with VTE become shorter, primary care will play an increasingly important role in the long-term management of these patients. Although the NOACs can potentially simplify patient management and improve clinical outcomes, primary care physicians may be less familiar with these new treatments compared with traditional therapy. To assist primary care physicians in further understanding the role of the NOACs, this article outlines the main differences between NOACs and traditional anticoagulation therapy and discusses the benefit–risk profile of the different NOACs in the treatment and secondary prevention of recurrent VTE. Key considerations for the use of NOACs in the primary care setting are highlighted, including dose transition, risk assessment and follow-up, duration of anticoagulant therapy, how to minimize bleeding risks, and the importance of patient education and counseling.

Non-Vitamin K Oral Anticoagulants in Stroke Patients: Practical Issues

Non-vitamin-K oral anticoagulants (NOACs) represent a major advance in the prevention of stroke in patients with atrial fibrillation (AF), offering a similar, if not superior, efficacy and safety profile and several practical advantages over oral vitamin K antagonists (VKAs). The rapid onset of action of the NOACs, their relatively short half-live, and the availability of specific reversal agents may be advantageous when managing acute ischemic strokes, and in the post-stroke, post-transient ischemic attack, and post-intracranial hemorrhage settings. In this review article, we offer practical guidance on the use of NOACs in these settings, focusing on managing the acute event and on initiating or resuming anticoagulation for secondary prevention. We also assess the use of NOACs to prevent stroke and bleeding in patients with AF who have chronic kidney disease, are elderly, or cognitively impaired, and we offer guidance on optimizing the use of NOACs and VKAs in these patient groups in the absence of evidence-based guidelines.

Efficacy of prothrombin complex concentrates for the emergency reversal of dabigatran-induced anticoagulation

Dabigatran is effective in decreasing the risk of ischaemic stroke in patients with atrial fibrillation. However, like all anticoagulants, it is associated with a risk of bleeding. In cases of trauma or emergency surgery, emergency reversal of dabigatran-induced anticoagulation may be required. A specific reversal agent for dabigatran, idarucizumab, has been approved by the US Food and Drug Administration. Alternative reversal agents are available, such as prothrombin complex concentrates (PCCs) and activated PCCs (aPCCs). In this review we evaluate the role of PCCs and aPCCs in the reversal of dabigatran anticoagulation and consider which tests are appropriate for monitoring coagulation in this setting. Pre-clinical studies, small clinical studies and case reports indicate that PCCs and aPCCs may be able to reverse dabigatran-induced anticoagulation in a dose-dependent manner. However, dosing based on coagulation parameters can be difficult because available assays may not provide adequate sensitivity and specificity for measuring anticoagulation induced by dabigatran or the countering effects of PCCs/aPCCs. In addition, PCCs or aPCCs can potentially provoke thromboembolic complications. Despite these limitations and the fact that PCCs and aPCCs are not yet licensed for dabigatran reversal, their use appears to be warranted in patients with life-threatening haemorrhage if idarucizumab is not available.

Use of direct oral anticoagulants with regional anesthesia in orthopedic patients

The use of direct oral anticoagulants including apixaban, rivaroxaban, and dabigatran, which are approved for several therapeutic indications, can simplify perioperative and postoperative management of anticoagulation. Utilization of regional neuraxial anesthesia in patients receiving anticoagulants carries a relatively small risk of hematoma, the serious complications of which must be acknowledged. Given the extensive use of regional anesthesia in surgery and the increasing number of patients receiving direct oral anticoagulants, it is crucial to understand the current clinical data on the risk of hemorrhagic complications in this setting, particularly for anesthesiologists. We discuss current data, guideline recommendations, and best practice advice on effective management of the direct oral anticoagulants and regional anesthesia, including in specific clinical situations, such as patients undergoing major orthopedic surgery at high risk of a thromboembolic event, or patients with renal impairment at an increased risk of bleeding.

Once-daily rivaroxaban for long-term stroke prevention in patients with atrial fibrillation

Oral anticoagulation is the long-term standard of care for preventing stroke in patients with atrial fibrillation (AF). However, anticoagulation is associated with an increased risk of bleeding, such that its use should be based on the absolute risks of stroke and bleeding, and the relative benefit-risk profile of the individual patient. Non-vitamin K antagonist oral anticoagulants, including rivaroxaban, are alternatives to vitamin K antagonists such as warfarin in this setting, and are supported in treatment guidelines as the optimal choice for patients with AF at moderate to high risk of stroke. Rivaroxaban can be given in fixed doses without routine coagulation monitoring, and phase III studies have demonstrated its safety profile and efficacy in patients with non-valvular AF, including the elderly and those with co-morbidities. Moreover, rivaroxaban is administered once daily, which has advantages for optimal patient adherence to medication over the long term. The established efficacy and safety profile of rivaroxaban, together with its convenient once-daily dosing schedule, may contribute to improved patient outcomes and lead to sustained benefits for patients with non-valvular AF at risk of stroke.

[Current state of treatment strategies for atrial fibrillation]

Atrial fibrillation is the most common form of persistent cardiac arrhythmia with a greatly increasing prevalence due to an aging population and increasing cardiovascular risk factors. Apart from impairment of the quality of life atrial fibrillation is associated with a high morbidity, most importantly stroke and heart failure. The therapy is complex and aims at improving symptoms as well as the prevention of thromboembolic complications, heart failure and aggravating comorbidities. Based on individual patient characteristics and symptoms therapy is mainly based on heart rate control by pharmacological means or therapy for maintaining sinus rhythm. This treatment includes antiarrhythmic drugs and catheter ablation. Current research is aimed at the investigation of the electrophysiological mechanisms of recurrent therapy refractive atrial fibrillation and the question whether the maintenance of sinus rhythm can improve the prognosis of atrial fibrillation.

The Influence of Assay Selection on Prothrombin Time Measured in Patients Treated With Rivaroxaban for Nonvalvular Atrial Fibrillation

BACKGROUND

Prothrombin time (PT) can provide a qualitative assessment of the relative intensity of anticoagulation by rivaroxaban. More than ten types of assay are available for the measurement of PT in clinical settings, but it is not yet fully understood whether their interactions with rivaroxaban are uniform or inconsistent.

METHODS

We examined 139 blood samples from patients taking rivaroxaban. We measured PT using five different commercially available assays. We also evaluated the estimated rivaroxaban concentration using a chromogenic anti-factor Xa assay.

RESULTS

The median estimated concentration of rivaroxaban was 192 ng/ml (interquartile range 85-284 ng/ml). The correlation coefficient (r) between PT and the estimated concentrations of rivaroxaban was as follows: Thromborel S, r = 0.768; Thrombocheck PT, r = 0.861; Coagpia PT-N, r = 0.909; Neoplastin Plus, r = 0.882; and Triniclot PT Excel S, r = 0.870. The gradients of the regression plots differed more than fourfold, and the standard deviation of the regression line ranged from 1.001 to 2.980, which tended to be higher for the assays with the higher regression slope gradients.

CONCLUSION

The estimated concentration of rivaroxaban varied greatly depending on the assay, so the PT measured in patients taking rivaroxaban should be interpreted with caution.

Stroke Prevention in Atrial Fibrillation: A Clinical Perspective on Trials of the Novel Oral Anticoagulants

Atrial fibrillation (AF) is a common heart rhythm disturbance; its incidence increases with age, and it is also an independent risk factor for stroke. Anticoagulation has been proven as the most effective way to reduce the risk of stroke in patients with AF, and vitamin K antagonists have been used for decades as the gold standard treatment. Vitamin K antagonists have a narrow therapeutic window in addition to variable pharmacokinetics and pharmacodynamics, and they frequently interact with food and other drugs, requiring coagulation monitoring to ensure balance between safety and efficacy. The novel oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, and edoxaban selectively target either thrombin or Factor Xa and have predictable pharmacologic profiles, removing the need for routine coagulation monitoring. This article summarizes phase III data in patient subtypes and discusses controversies surrounding AF management with these agents. Results indicate that NOACs in non-valvular AF have an overall improved efficacy-safety profile compared with warfarin. Significantly fewer fatal bleeding events were observed in patients randomized to rivaroxaban, apixaban, or edoxaban compared with those on warfarin, and significant reductions in the incidence of life-threatening bleeding were observed in patients randomized to dabigatran. All four pivotal trials testing the NOACs against warfarin showed significantly lower rates of intracranial bleeding in patients administered NOACs. These results suggest that wider use of NOACs has the potential to improve outcomes for most patients with AF.

Why switch from warfarin to NOACs?

Several patients with non-valvular atrial fibrillation treated with warfarin or other vitamin-K antagonists (VKA) might benefit from switching to an oral non vitamin-K antagonist anticoagulant (NOAC). In the absence of randomised comparative trials of switching to NOACs versus maintaining VKA treatment, several considerations argue in favour of a switching strategy. First, there is conclusive evidence that haemorrhagic strokes and intracranial bleedings are much fewer in number with NOACs than with warfarin. The risk of intracranial bleeding is 52 % lower with NOACS than with warfarin, with extremes ranging from 33 to 70 %. Such benefit is applicable to different NOACs, and independent of the time-in-therapeutic range under warfarin. Patients at increased risk for intra-cranial bleeding (renal dysfunction, or prior stroke or intra-cranial bleeding) should benefit most from switching to NOACs. Patients with labile International Normalized Ratio are also considered good candidates for switching because of their increased risk of stroke, and the lack of interactions between the effects of NOACs versus warfarin and the time-in-therapeutic range. Furthermore, some NOACs proved to be superior to warfarin in reducing the risk of thromboembolic complications even in intention-to-treat analyses. As further advantage, NOACs show fewer drug-drug and drug-food interactions when compared with warfarin. Last, but not least, NOACs do not need frequent blood drawings except in patients with moderate renal dysfunction, in whom periodic controls of serum creatinine are generally advised. The higher cost remains a barrier to a wider use of NOACs, especially in low-income settings.

Novel oral anticoagulants in plastic surgery

Novel oral anticoagulants (NOACs) have emerged as a good alternative to warfarin in the prevention of stroke for patients with atrial fibrillation. NOAC use is increasing rapidly; therefore, greater understanding of their use in the perioperative period is important for optimal care. Studies and reviews that reported on the use of NOACs were identified, with particular focus on the perioperative period. PubMed was searched for relevant articles published between January 2000 and August 2015. The inevitable rise in the use of NOACs such as rivaroxaban (Xarelto™), apixaban (Eliquis™), edoxaban (Lixiana™) and dabigatran (Pradaxa™) may present a simplified approach to perioperative anticoagulant management due to fewer drug interactions, rapidity of onset of action and relatively short half-lives. Coagulation status, however, cannot reliably be monitored and no antidotes are currently available. When planning for discontinuation of NOACs, special consideration of renal function is required. Advice regarding the management of bleeding complications is provided for consideration in emergency surgery. In extreme circumstances, haemodialysis may be considered for bleeding with the use of dabigatran. NOACs will increasingly affect operative planning in plastic surgery. In order to reduce the incidence of complications associated with anticoagulation, the management of NOACs in the perioperative period requires knowledge of the time of last dose, renal function and the bleeding risk of the planned procedure. Consideration of these factors will allow appropriate interpretation of the current guidelines.

New Direct Oral Anticoagulants (DOAC) and Their Use Today

The ideal anticoagulant is oral, has a wide therapeutic range, predictable pharmacokinetics and pharmacodynamics, a rapid onset of action, an available antidote, minimal side effects and minimal interactions with other drugs or food. With the development of the novel direct oral anticoagulants (DOAC), we now have an alternative to the traditional vitamin K antagonists (VKA) for the prevention and treatment of thrombosis. DOACs have limited monitoring requirements and very predictable pharmacokinetic profiles. They were shown to be non-inferior or superior to VKA in the prophylaxis or treatment of thromboembolic events. Particularly in terms of safety they were associated with less major bleeding, including intracranial bleeding, thus providing a superior benefit for the prevention of stroke in patients with atrial fibrillation. Despite these advantages, there are remaining limitations with DOACs: their dependence on renal and hepatic function for clearance and the lack of an approved reversal agent, whereas such antidotes are successively being made available. DOACs do not need regular monitoring to assess the treatment effect but, on the other hand, they interact with other drugs and interfere with functional coagulation assays. From a practical point of view, the properties of oral administration, simple dosing without monitoring, a short half-life allowing for the possibility of uncomplicated switching or bridging, and proven safety overwhelm the disadvantages, making them an attractive option for short- or long-term anticoagulation.

Management of Venous Thromboembolism: Recent Advances in Oral Anticoagulation Therapy

OBJECTIVE

To review clinical data on direct oral anticoagulants (DOACs) used in the acute treatment of venous thromboembolism (VTE) as well as practical considerations when using these products.

DATA SOURCES

Searches of PubMed and Google Scholar for VTE, deep vein thrombosis, pulmonary embolism, and relevant drug international nonproprietary names were conducted. Additional online searches were conducted for prescribing information.

STUDY SELECTION AND DATA EXTRACTION

Relevant articles on dabigatran, rivaroxaban, apixaban, and edoxaban for the management of VTE compared with oral vitamin K antagonists (VKAs; published between 1966 and December 2015) were reviewed and summarized, together with information on dosing, pharmacokinetics/pharmacodynamics, and drug-drug interactions.

DATA SYNTHESIS

The DOACs have the potential to circumvent many of the disadvantages of VKAs. At a minimum, they greatly increase the available therapeutic options, thus providing a greater opportunity for clinicians to select a management option that best fits the needs of individual patients. Despite the significant advance that DOACs represent, they are not without risk and require careful consideration of a number of clinical issues to optimize safety and efficacy.

CONCLUSIONS

The emergence of DOACs for the management of thromboembolic disorders represents a paradigm shift from oral VKAs. The DOACs provide similar efficacy and improved safety in selected patients as compared with VKAs. Clinicians treating VTE need to be familiar with the intricacies involved in using these agents, including the appropriate dose selection for the relevant indication, avoidance of drug-drug and drug-disease interactions, and consideration of dose adjustments in specific clinical situations, such as organ dysfunction.

[Typical atrial flutter: Diagnosis and therapy]

Typical, cavotricuspid-dependent atrial flutter is the most common atrial macroreentry tachycardia. The incidence of atrial flutter (typical and atypical forms) is age-dependent with 5/100,000 in patients less than 50 years and approximately 600/100,000 in subjects > 80 years of age. Concomitant heart failure or pulmonary disease further increases the risk of typical atrial flutter.Patients with atrial flutter may present with symptoms of palpitations, reduced exercise capacity, chest pain, or dyspnea. The risk of thromboembolism is probably similar to atrial fibrillation; therefore, the same antithrombotic prophylaxis is required in atrial flutter patients. Acutely symptomatic cases may be subjected to cardioversion or pharmacologic rate control to relieve symptoms. Catheter ablation of the cavotricuspid isthmus represents the primary choice in long-term therapy, associated with high procedural success (> 97 %) and low complication rates (0.5 %).This article represents the third part of a manuscript series designed to improve professional education in the field of cardiac electrophysiology. Mechanistic and clinical characteristics as well as management of isthmus-dependent atrial flutter are described in detail. Electrophysiological findings and catheter ablation of the arrhythmia are highlighted.

How to choose appropriate direct oral anticoagulant for patient with nonvalvular atrial fibrillation

The novel oral anticoagulants or direct oral anticoagulants (DOAC) are becoming more common in clinical practice for the prevention of stroke in non-valvular atrial fibrillation (NVAF). The availability of several agents with similar efficacy and safety for stroke prevention in NVAF patients offers more selection, but at the same time requires certain knowledge to make a good choice. This comparative analysis provides an appraisal of the respective clinical trials and highlights much of what remains unknown about four FDA-approved agents: dabigatran, apixaban, rivaroxaban, and edoxaban. It details how the DOACs compare to warfarin and to one another summarizes pharmacologic and pharmacodynamic properties, and drug interactions from the stand point of practical consequences of these findings. Common misconceptions and reservations are addressed. The practical application of this data is intended to help choosing the most appropriate agent for individual NVAF patient.