Dabigatran etexilate: a new oral thrombin inhibitor

The beneficial effects of a direct thrombin inhibitor, dabigatran etexilate, on the development and stability of atherosclerotic lesions in apolipoprotein E-deficient mice : dabigatran etexilate and atherosclerosis

PURPOSE

Dabigatran etexilate (DE) constitutes a novel, direct thrombin inhibitor. Regarding the association of thrombin with atherogenesis, we assessed the effects of DE on the development and stability of atherosclerotic lesions in apolipoprotein-E deficient (ApoE-/-) mice.

MATERIALS-METHODS

Fifty male ApoE-/- mice were randomized to receive western-type diet either supplemented with DE 7.5 mg DE/g chow) (DE-group, n = 25) or matching placebo as control (CO-group, n = 25) for 12 weeks. After this period, all mice underwent carotid artery injury with ferric chloride and the time to thrombotic total occlusion (TTO) was measured. Then, mice were euthanatized and each aortic arch was analyzed for the mean plaque area, the content of macrophages, elastin, collagen, nuclear factor kappaB (NFκB), vascular cell adhesion molecule-1 (VCAM-1), matrix metalloproteinase-9 (MMP-9) and its inhibitor (TIMP-1).

RESULTS

DE-group showed significantly longer TTO compared to CO-group (8.9 ± 2.3 min vs 3.5 ± 1.1 min, p < 0.001) and the mean plaque area was smaller in DE-group than CO-group (441.00 ± 160.01 × 10(3) μm(2) vs 132.12 ± 32.17 × 10(3) μm(2), p < 0.001). Atherosclerotic lesions derived from DE-treated mice showed increased collagen (p = 0.043) and elastin (p = 0.031) content, thicker fibrous caps (p < 0.001) and reduced number of internal elastic lamina ruptures per mm of arterial girth (p < 0.001) when compared to CO-group. Notably, DE treatment seemed to promote plaque stability possibly by reducing concentrations of NFκB, VCAM-1, macrophages and MMP-9 and increasing TIMP-1 within atherosclerotic lesions (p < 0.05).

CONCLUSIONS

DE attenuates arterial thrombosis, reduces lesion size and may promote plaque stability in ApoE-/- mice. The plaque-stabilizing effects of chronic thrombin inhibition might be the result of the favorable modification of inflammatory mechanisms.

The discovery of dabigatran etexilate

Thromboembolic disease is a major cause of mortality and morbidity in the developed world and is caused by an excessive stimulation of coagulation. Thrombin is a key serine protease in the coagulation cascade and numerous efforts have been made to develop safe and effective orally active direct thrombin inhibitors (DTIs). Current anticoagulant therapy includes the use of indirect thrombin inhibitors (e.g., heparins, low-molecular-weight-heparins) and vitamin K antagonists such as warfarin. However there are several caveats in the clinical use of these agents including narrow therapeutic window, parenteral delivery, and food- and drug-drug interactions. Dabigatran is a synthetic, reversible DTI with high affinity and specificity for its target binding both free and clot-bound thrombin, and offers a favorable pharmacokinetic profile. Large randomized clinical trials have demonstrated that dabigatran provides comparable or superior thromboprophylaxis in multiple thromboembolic disease indications compared to standard of care. This minireview will highlight the discovery and development of dabigatran, the first in a class of new oral anticoagulant agents to be licensed worldwide for the prevention of thromboembolism in the setting of orthopedic surgery and stroke prevent in atrial fibrillation.

Antithrombotic therapy for stroke prevention in non-valvular atrial fibrillation

The world faces an epidemic of atrial fibrillation and atrial fibrillation-related stroke. An individual's risk of atrial fibrillation-related stroke can be estimated with the CHADS(2) or CHA(2)DS(2)VASc scores, and reduced by two-thirds with effective anticoagulation. Vitamin K antagonists, such as warfarin, are underused and often poorly managed. The direct thrombin inhibitor dabigatran etexilate and factor Xa inhibitors rivaroxaban and apixaban are new oral anticoagulants that are at least as efficacious and safe as warfarin. Their advantages are predictable anticoagulant effects, low propensity for drug interactions, and lower rates of intracranial haemorrhage than with warfarin. A disadvantage is the continuing need to develop and validate rapidly effective antidotes for major bleeding and standardised tests that accurately measure plasma concentrations and anticoagulant effects, together with the disadvantage of possible higher rates of gastrointestinal haemorrhage and greater expense than with warfarin. The new oral anticoagulants should increase the number of patients with atrial fibrillation at risk of stroke who are optimally anticoagulated, and reduce the burden of atrial fibrillation-related stroke.

Gastrointestinal disorders and dabigatran

Anticoagulants play an important role in the prevention and treatment of a variety of acute and chronic thromboembolic disorders such as primary prevention and treatment of venous thromboembolism or prevention of stroke and systemic embolism in atrial fibrillation just to name of few. Within recent years, a promising new oral anticoagulant, the direct thrombin inhibitor dabigatran etexilate (dabigatran) successfully underwent clinical development and has emerged as an alternative to vitamin K antagonists according to a variety of recently revised and updated international guidelines referring to the indication of stroke prevention in atrial fibrillation. Considering the intensive clinical use of vitamin K antagonists in the mentioned indication as well as the widespread and increasing therapeutic need on one hand and the likely availability of a more efficacious alternative with fewer limitations in clinical practice on the other, there is good reason to assume that the use of dabigatran may be broad within the general medical community in the near future. Based on what is currently published in the public domain and clinical trial data it is suggested that dabigatran etexilate is associated with higher rates of dyspeptic symptoms compared to warfarin. Therefore, it is the authors' intent to review and discuss this potential dyspeptic side effect profile of dabigatran and potential counter measures from a gastroenterologist's perspective.

Dabigatran effects on the international normalized ratio, activated partial thromboplastin time, thrombin time, and fibrinogen: a multicenter, in vitro study

BACKGROUND

Patients receiving the direct thrombin inhibitor dabigatran may have selected anticoagulation assays performed as part of routine care. The effect of dabigatran on the international normalized ratio (INR), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen requires clarification.

OBJECTIVE

To describe the effect of dabigatran on selected assays in North America and the United Kingdom.

METHODS

Pooled normal plasma enriched with dabigatran at concentrations of 25, 50, 75, 100, 125, 150, 200, 300, 400, and 500 ng/mL were sent blinded to 19 centers in the US, the UK, and Canada to assess the effect of dabigatran on routine coagulation screening tests, the INR, aPTT, TT, and fibrinogen.

RESULTS

Data were returned from 16 centers. For effects on INR, Neoplastine CI Plus and Simplastin HTF were the most sensitive and Thromborel S the least sensitive to increasing dabigatran concentrations. For the aPTT, all reagents demonstrated decreasing sensitivity to increasing dabigatran concentrations. Measured fibrinogen either demonstrated no change or factitious decrease with increasing dabigatran concentrations. Commercial TT methods were very sensitive to low concentrations of dabigatran, with 9 of 10 reporting sites exceeding test limits at dabigatran concentrations of 100 ng/mL.

CONCLUSIONS

The INR, aPTT, and TT rise as dabigatran concentrations increase. Both the INR and aPTT increase in a linear pattern with marginal slopes, creating challenges in using these assays as reliable means for assessing the amount of dabigatran present. The commercial TT assay is very sensitive at low concentrations of dabigatran. Fibrinogen test results may be either unaffected or lower in the presence of dabigatran.

[Scope of the latest RE-LY substudies: clinical implications]

The approval of the use of dabiatran in stroke prevention in patients with nonvalvular atrial fibrilation (NVAF) is based on the results of the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial, one of the largest studies to date in this entity. In this trial, dabigatran showed similar safety and efficacy to warfarin in primary and secondary prevention of stroke in patients with AF. At a dose of 150 mg twice daily, dabigatran was superior to warfarin in the prevention of stroke or systemic embolism and the 110 mg dose twice daily showed similar efficacy and greater safety, given the lower incidence of hemorrhage. These results were consistently found in the various subanalyses, with some slight differences of interest for clinical practice. The ideal candidates for dabiatran are patients with NVAF suitable for cardioversion, who require short periods of anticoagulation, patients in remote geographical areas with difficulty in achieving good anticoagulation control or good control with anti-vitamin K treatment due to IRN fluctuations, and patients with a low risk of hemorrhage and a CHADS score ≥ 3 and/or with prior stroke, whenever there are no contraindications. The choice of dabigatran dose should be evaluated according to the patient's individual characteristics (caution must be exercised when prescribing this drug in the elderly and in renal insufficiency) and embolic and/or hemorrhagic risk. Studies of the long-term safety of this drug, pharmacoeconomic analyses in Spain and post-commercialization pharmacovigilance data are required before the definitive uses of this drug can be established.

Management of venous thromboembolism in patients with advanced gastrointestinal cancers: what is the role of novel oral anticoagulants?

Venous thromboembolism (VTE) is a frequent complication of gastrointestinal cancers that increases morbidity and may impact mortality. Low-molecular-weight heparins (LMWHs) and vitamin K antagonists (VKAs) are standard anticoagulation options for the ambulatory gastrointestinal cancer patient with VTE, but both of these agents are challenging to use for various reasons. Novel oral anticoagulants (NOAs) are new, orally available anticoagulants designed to be easier to administer with more reliable pharmacokinetics that eliminate the need for frequent monitoring of various laboratory parameters. This paper reviews the existing efficacy and safety data for the use of NOAs dabigatran etexilate, rivaroxaban, and apixaban and discusses the potential role of these agents in the management of gastrointestinal cancer-related VTE.

Dabigatran: a primer for neurosurgeons

OBJECTIVE

This study sought to present an overview of dabigatran, a new anticoagulant, and to discuss the implications for the perioperative management of patients taking dabigatran.

METHODS

We reviewed the English literature pertaining to the new oral anticoagulant, dabigatran (Pradaxa).

RESULTS

Dabigatran has the advantage of providing rapid and steady anticoagulation without requiring laboratory monitoring. However, the fact that no practical, reliable method of monitoring of the anticoagulant effects is available constitutes a challenge when contemplating urgent neurosurgical procedures in patients treated with this medication. Although the risk of intracranial hemorrhage with dabigatran was lower than with warfarin in the large trial leading to the approval of the drug, the management of these complications may be problematic because there is no current antidote.

CONCLUSIONS

We present a basic overview of dabigatran, discuss the implications for the perioperative management of patients taking this new anticoagulant, and offer recommendations for the management of intracranial hemorrhage related to this drug.

Prevention of stroke in patients with atrial fibrillation: anticoagulant and antiplatelet options

As the population ages, the prevalence of atrial fibrillation (AF) continues to rise. The most feared complication of this common cardiac arrhythmia is cardioembolic stroke. Strokes related to AF are associated with greater morbidity and mortality than ischemic strokes of most other etiologies and impose a substantial economic burden on healthcare systems around the world. Until recently, warfarin was the sole anticoagulant proven effective for stroke prevention patients with AF at elevated risk, but its narrow therapeutic margin and variable dose response limited clinical utility. The emergence of new anticoagulants that offer equal or superior efficacy, greater safety and the convenience of fixed oral dosing may make warfarin the less preferred option. This review provides an update on recent advancements in antithrombotic therapy for stroke prevention in patients with AF.

Dabigatran for stroke prevention in nonvalvular atrial fibrillation: answers to challenging "real-world" questions

Dabigatran etexilate is a novel, oral, reversible, direct thrombin inhibitor that constitutes a major breakthrough for stroke prevention in patients with nonvalvular atrial fibrillation (AF). Dabigatran was the first new oral anticoagulant approved in Europe and became available in Portugal, for stroke prevention in nonvalvular AF, earlier than in most European countries. This paper is the joint effort of a panel of experts from different specialties and provides information on the use of dabigatran, in anticipation of the challenges that will come with increased usage.

Reversal of antithrombotic agents

Anticoagulants are the mainstay of therapy for thromboembolic diseases. In addition to the more traditional agents, new oral anticoagulants, including dabigatran etexilate, rivaroxaban, and apixaban, have been shown to be effective across several indications. Bleeding is a serious complication associated with any anticoagulant, but many of the traditional parenteral and new oral agents do not currently have specific antidotes. This review describes available and future options for the reversal of the effects of anticoagulants, in particular the new oral agents and discusses current management strategies for bleeding events in clinical practice.

Direct thrombin inhibitors in cardiovascular disease

Limitations of commonly used anticoagulants, unfractionated heparin, low-molecular-weight heparin, and oral vitamin K antagonists have prompted the development of alternative therapies. Direct thrombin inhibitors are a new class of anticoagulants that bind directly to thrombin and inhibit its interaction with substrates. In this Review, we critically examine the evidence from randomized controlled trials for the efficacy and safety of the parenteral direct thrombin inhibitors bivalirudin and argatroban, and the novel oral direct thrombin inhibitor dabigatran etexilate, in cardiovascular and thrombotic disease.

The role of structural information in the discovery of direct thrombin and factor Xa inhibitors

The quest for novel medications to treat thromboembolic disorders such as venous thrombosis, pulmonary embolism and stroke received a boost when the 3D structures of two major players in the blood coagulation cascade were determined in 1989 and 1993. Structure-guided design of inhibitors of thrombin (factor IIa, fIIa) and factor Xa (fXa) eventually led to the discovery of potent, selective, efficacious, orally active and safe compounds that proved successful in clinical studies. In 2008, the direct thrombin inhibitor dabigatran etexilate developed by Boehringer Ingelheim became the first novel antithrombotic molecular entity to enter the market in 50 years. Additional compounds targeting factor Xa were subsequently granted marketing authorization or are in late-stage clinical studies. In this review, I use selected case studies to describe the discovery of novel fIIa and fXa inhibitors, with a particular emphasis on the pre-eminent role that structural information played in this process.

The management of anticoagulants perioperatively

Perioperative management of anticoagulants requires one to balance the patient's risk factors for operative bleeding, the type of operation to be performed, and the patient's risk of thromboembolism. At present, no set algorithm exists for the perioperative management of all the anticoagulants. In this article, we address the perioperative management of the most commonly used anticoagulants seen in practice today, such as warfarin, heparin, dabigatran, clopidogrel, and aspirin, for the most commonly performed general thoracic operations.

Novel Oral Anticoagulation in Management of Venous Thromboembolism, Atrial Fibrillation, and Acute Coronary Syndrome

Venous thromboembolism (VTE) is a major public health concern since the incidence of VTE rises substantially with age. Furthermore, the diagnosis can be elusive since patients can present differently, causing delay in diagnosis and initiation of treatment and resulting in major morbidity and mortality. In addition to accuracy and precision in diagnosis, antithrombotic therapies are the cornerstones of VTE management. In traditional paradigm, vitamin K antagonists (warfarin), indirect factor Xa inhibitors, and heparin are the foundation in management of VTE. Warfarin has been the only available oral anticoagulant therapy for several decades. Although warfarin is effective in both treatment and prophylaxis against VTE, there are several limitations. Therefore, the novel anticoagulation therapies, including rivaroxaban, apixaban, and dabigatran etexilate, have apparent advantages over warfarin in terms of clinical efficacy and adverse effects. The objective of this review is to describe the background and clinical implications of these novel anticoagulants.

Dabigatran: Will it Replace Warfarin for Stroke Prevention in Atrial Fibrillation?

Dabigatran, a direct thrombin inhibitor, is the first oral alternative to warfarin for stroke prevention in atrial fibrillation. Dabigatran offers several potential advantages over warfarin including ease of dosing, fewer drug interactions, and the lack of required coagulation monitoring. However, its overall effectiveness and safety will depend upon appropriate patient selection. This article discusses factors that should be taken into account when considering dabigatran for patients with atrial fibrillation.

Effects of FEIBA on platelet and leucocyte activation in severe haemophilia patients with inhibitors

Factor eight inhibitory bypassing agent (FEIBA) is used as a therapeutic option in haemophilia patients who have developed inhibitors. The measurement of thrombin generation has been applied to monitor the efficacy of FEIBA. However, a major concern about the clinical use of FEIBA is whether or not an increase in thrombin activity causes subsequent platelet activation and risk of thrombosis. Our aim is to evaluate whether FEIBA causes platelet and leucocyte activation in haemophilia patients with inhibitors. We evaluated the effects of FEIBA on platelet and leucocyte activity in correlation with thrombin generation. Initially, an in vitro study was conducted to evaluate the effects of FEIBA on platelet and leucocyte activity (using flow cytometry) using peripheral blood from normal volunteers. We then performed an ex vivo study looking at the effect of FEIBA on the above parameters in two haemophiliacs with high-titre inhibitors. A parallel study was also carried out ex vivo to evaluate thrombin generation using a thrombinoscope. FEIBA did not cause platelet or leucocyte activation in either the in vitro or ex vivo studies but showed a predictable increase in thrombin generation. Our study is the first one to address the effect of FEIBA on platelet and leucocyte function. We found no evidence of 'systemic' platelet activation. The findings suggest that whilst FEIBA improves global haemostasis, platelet activation is likely to be contained to the site of injury and systemic platelet activation, a previously feared consequence of FEIBA infusion that that may have contributed to thrombotic risk is absent.

Dabigatran etexilate for stroke prevention in patients with atrial fibrillation: resolving uncertainties in routine practice

Dabigatran etexilate is a new oral anticoagulant recently approved in Europe for the prevention of stroke or systemic embolism in adult patients with non-valvular atrial fibrillation (AF) and at least one risk factor for stroke. With a fast onset of action and a predictable anticoagulant effect obviating the need for coagulation monitoring, dabigatran etexilate offers practical advantages over vitamin K antagonists in clinical practice. However, clinicians may have questions about practical aspects of dabigatran etexilate use including monitoring anticoagulant efficacy, interruption for surgical or invasive procedures and management of bleeding. This review article aims to address these concerns and provide guidance on the use of dabigatran etexilate in special situations, such as acute coronary syndromes and cardiac revascularisation. In addition, cut-off values for different coagulation assay results associated with an increased risk of bleeding are given.

Heparin-induced thrombocytopenia: in vitro studies on the interaction of dabigatran, rivaroxaban, and low-sulfated heparin, with platelet factor 4 and anti-PF4/heparin antibodies

Heparin is a widely used anticoagulant. Because of its negative charge, it forms complexes with positively charged platelet factor 4 (PF4). This can induce anti-PF4/heparin IgG Abs. Resulting immune complexes activate platelets, leading to the prothrombotic adverse drug reaction heparin-induced thrombocytopenia (HIT). HIT requires treatment with alternative anticoagulants. Approved for HIT are 2 direct thrombin inhibitors (DTI; lepirudin, argatroban) and danaparoid. They are niche products with limitations. We assessed the effects of the DTI dabigatran, the direct factor Xa-inhibitor rivaroxaban, and of 2-O, 3-O desulfated heparin (ODSH; a partially desulfated heparin with minimal anticoagulant effects) on PF4/heparin complexes and the interaction of anti-PF4/heparin Abs with platelets. Neither dabigatran nor rivaroxaban had any effect on the interaction of PF4 or anti-PF4/heparin Abs with platelets. In contrast, ODSH inhibited PF4 binding to gel-filtered platelets, displaced PF4 from a PF4-transfected cell line, displaced PF4/heparin complexes from platelet surfaces, and inhibited anti-PF4/heparin Ab binding to PF4/heparin complexes and subsequent platelet activation. Dabigatran and rivaroxaban seem to be options for alternative anticoagulation in patients with a history of HIT. ODSH prevents formation of immunogenic PF4/heparin complexes, and, when given together with heparin, may have the potential to reduce the risk for HIT during treatment with heparin.

Dabigatran etexilate versus warfarin in management of non-valvular atrial fibrillation in UK context: quantitative benefit-harm and economic analyses

OBJECTIVES

To determine the incremental net health benefits of dabigatran etexilate 110 mg and 150 mg twice daily and warfarin in patients with non-valvular atrial fibrillation and to estimate the cost effectiveness of dabigatran in the United Kingdom.

DESIGN

Quantitative benefit-harm and economic analyses using a discrete event simulation model to extrapolate the findings of the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) study to a lifetime horizon.

SETTING

UK National Health Service. Population Cohorts of 50,000 simulated patients at moderate to high risk of stroke with a mean baseline CHADS(2) (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes mellitus, previous Stroke/transient ischaemic attack) score of 2.1.

MAIN OUTCOME MEASURES

Quality adjusted life years (QALYs) gained and incremental cost per QALY of dabigatran compared with warfarin.

RESULTS

Compared with warfarin, low dose and high dose dabigatran were associated with positive incremental net benefits of 0.094 (95% central range -0.083 to 0.267) and 0.146 (-0.029 to 0.322) QALYs. Positive incremental net benefits resulted for high dose dabigatran in 94% of simulations versus warfarin and in 76% of those versus low dose dabigatran. In the economic analysis, high dose dabigatran dominated the low dose, had an incremental cost effectiveness ratio of £23,082 (€26,700; $35,800) per QALY gained versus warfarin, and was more cost effective in patients with a baseline CHADS(2) score of 3 or above. However, at centres that achieved good control of international normalised ratio, such as those in the UK, dabigatran 150 mg was not cost effective, at £42,386 per QALY gained.

CONCLUSIONS

This analysis supports regulatory decisions that dabigatran offers a positive benefit to harm ratio when compared with warfarin. However, no subgroup for which dabigatran 110 mg offered any clinical or economic advantage over 150 mg was identified. High dose dabigatran will be cost effective only for patients at increased risk of stroke or for whom international normalised ratio is likely to be less well controlled.

[New anticoagulants. Characteristics, monitoring and management of bleeding]

Vitamin K antagonists and heparins have been standard anticoagulation drugs over the past decades. They are effective and safe but they have several drawbacks which has led to the development of new oral anticoagulants. Dabigatran etexilate is a specific oral thrombin inhibitor and rivaroxaban and apixaban are oral inhibitors of factor Xa. These agents produce a predictable anticoagulant response after fixed-dose administration so that routine coagulation monitoring is unnecessary. Currently, dabigatran etexilate, rivaroxaban and apixaban are licensed for thromboprophylaxis after elective total hip or knee replacement surgery. Since august 2011, dabigatran etexilate is licensed for patients with atrial fibrillation, rivaroxaban will follow. However, indications will be expanded e.g. for therapy of venous thromboembolism. It is important to be aware of the pharmacokinetic and pharmacodynamic profiles of these new agents. The drugs considerably influence the global test of coagulation thus making an interpretation of test results difficult. Currently, there is a lack of suitable coagulation tests to monitor anticoagulation in emergency cases, such as bleeding. Specific antidotes are not yet available.

Advances in anticoagulation: focus on dabigatran, an oral direct thrombin inhibitor

Dabigatran is an oral direct thrombin inhibitor with a rapid onset. Patients on dabigatran do not require coagulation monitoring. Recent prospective randomized trials have shown the efficacy of dabigatran for the prevention of venous thromboembolism after knee or hip arthroplasty and for the prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. Because dabigatran is cleared principally by the kidneys, dosage adjustments are required in the setting of renal dysfunction. There currently is no reversal agent for dabigatran although hemodialysis can facilitate its rapid removal in life-threatening circumstances. The management of severe bleeding associated with dabigatran also may include the administration of a procoagulant, such as recombinant activated factor VII. Based on recent guidelines, regional anesthesia should be used cautiously in patients taking this novel oral thrombin inhibitor.

Stroke Genetics Update: 2011

Although stroke remains a leading cause of disability and mortality worldwide, recently there have been significant advances related to our understanding of the genetic basis of stroke. Ongoing research efforts put us on the cusp for major breakthroughs in the field. In this review, we present the substantial evidence for the contribution of genetic variation to the development of stroke, and the difficulties posed in the study of stroke given the numerous genetically driven risk factors and stroke subtypes. We emphasize recent findings implementing candidate gene and genome-wide association approaches. We then discuss how emerging knowledge is informing and reshaping our understanding of stroke biology and how, in the near term, genetics may be used clinically to identify individuals who are at risk of disease or who may derive benefit from specific treatment modalities. Lastly, we address ongoing and future approaches that will continue to improve our understanding of stroke genetics.

Anticoagulation therapy in older adults newly diagnosed with atrial fibrillation

Atrial fibrillation (AF) is the most common chronic arrhythmia and the most serious heart rhythm irregularity in individuals older than 70. It is usually not life threatening in and of itself, but it can lead to serious medical problems, including stroke, additional heart rhythm problems, and heart failure. Symptoms of AF vary considerably. Some patients are asymptomatic and have a self-limiting arrhythmia of short duration that converts to normal sinus without any intervention. Symptomatic patients may experience minor palpitations, severe palpitations, or even more vague symptoms such as lightheadedness, shortness of breath, or fatigue. More serious symptoms, such as syncope, new or worsening heart failure, or a cerebral vascular accident, may occur. The initial goals of treatment include controlling ventricular rate and addressing anticoagulation status. New guidelines help clinicians effectively manage anticoagulant therapy for older adults newly diagnosed with AF.