Reversal of target-specific oral anticoagulants

Perioperative management of patients receiving non-vitamin K antagonist oral anticoagulants: up-to-date recommendations

Indications of non-vitamin K antagonist oral anticoagulants (NOACs), consisting of two types: direct thrombin inhibitor (dabigatran) and direct factor Xa inhibitor (rivaroxaban, apixaban, and edoxaban), have expanded over the last few years. Accordingly, increasing number of patients presenting for surgery are being exposed to NOACs, despite the fact that NOACs are inevitably related to increased perioperative bleeding risk. This review article contains recent clinical evidence-based up-to-date recommendations to help set up a multidisciplinary management strategy to provide a safe perioperative milieu for patients receiving NOACs. In brief, despite the paucity of related clinical evidence, several key recommendations can be drawn based on the emerging clinical evidence, expert consensus, and predictable pharmacological properties of NOACs. In elective surgeries, it seems safe to perform high-bleeding risk surgeries 2 days after cessation of NOAC, regardless of the type of NOAC. Neuraxial anesthesia should be performed 3 days after cessation of NOACs. In both instances, dabigatran needs to be discontinued for an additional 1 or 2 days, depending on the decrease in renal function. NOACs do not require a preoperative heparin bridge therapy. Emergent or urgent surgeries should preferably be delayed for at least 12 h from the last NOAC intake (better if > 24 h). If surgery cannot be delayed, consider using specific reversal agents, which are idarucizumab for dabigatran and andexanet alfa for rivaroxaban, apixaban, and edoxaban. If these specific reversal agents are not available, consider using prothrombin complex concentrates.

Emergency care of patients receiving non-vitamin K antagonist oral anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs), which inhibit thrombin (dabigatran) and factor Xa (rivaroxaban, apixaban, edoxaban) have been introduced in several clinical indications. Although NOACs have a favourable benefit-risk profile and can be used without routine laboratory monitoring, they are associated-as any anticoagulant-with a risk of bleeding. In addition, treatment may need to be interrupted in patients who need surgery or other procedures. The objective of this article, developed by a multidisciplinary panel of experts in thrombosis and haemostasis, is to provide an update on the management of NOAC-treated patients who experience a bleeding episode or require an urgent procedure. Recent advances in the development of targeted reversal agents are expected to help streamline the management of NOAC-treated patients in whom rapid reversal of anticoagulation is required.

Anticoagulation strategies for venous thromboembolism: moving towards a personalised approach

Four non-vitamin K antagonist oral anticoagulants (NOACs) have now been evaluated in clinical trials, providing new therapeutic options for the treatment of venous thromboembolism (VTE). Recent position statements call for a move towards tailored recommendations for the treatment of VTE, to better define in whom and under what conditions a particular anticoagulant may improve clinical outcomes. Here we review the phase III data on NOAC trials for the treatment of VTE, assessing the favourability of agents for particular patient subgroups and aetiologies. Where the data permit, individualised risks of recurrent VTE events and bleeding are presented.

Clinical impact and course of major bleeding with edoxaban versus vitamin K antagonists

Edoxaban is a once-daily direct oral anticoagulant (DOAC). The Hokusai-VTE study revealed that, after initial treatment with heparin, edoxaban was non-inferior to and safer than vitamin K antagonists (VKA) in the prevention of recurrent deep-vein thrombosis and pulmonary embolism. This is the first report on the clinical relevance and management of bleeding events with edoxaban. All major bleeding events were classified blindly by three study-independent adjudicators. Predefined criteria were used to classify severity of clinical presentation and, separately, the clinical course and outcome into four categories. Major bleeding occurred in 56 patients treated with edoxaban and 65 patients treated with VKA. The severest categories (3 or 4) of the clinical presentation were assigned to 46 % of the major bleeding episodes in edoxaban recipients versus 58 % of the major bleeds in VKA recipients (odds ratio [OR] 0.62, 95 % confidence interval [CI] 0.30–1.27, p = 0.19). Clinical course was classified as severe (category 3 or 4) in 23 % of the edoxaban and 29 % of the VKA associated bleeds (OR 0.73, 95 % CI 0.32–1.66, p = 0.46). In conclusion, edoxaban associated major bleeding events have a comparable clinical presentation and course to major bleeds with VKA in patients treated for venous thromboembolism in the Hokusai-VTE study. These results may assure physicians that it is safe to prescribe this medication. If a major bleeding during edoxaban treatment occurs, its clinical presentation and clinical course are not worse than in VKA-treated patients.

Rectus Sheath Hematoma Associated with Apixaban

Apixaban is an oral anticoagulant that directly inhibits Factor Xa and is indicated for the prophylaxis and treatment of deep venous thrombosis and stroke prevention in non-valvular atrial fibrillation. Rectus sheath hematoma is a rare, life-threatening complication of anticoagulant treatment. We describe a case of an elderly patient on apixaban for the treatment of deep venous thrombosis who developed severe abdominal pain during hospitalization. Computed tomography of the abdomen revealed left rectus sheath hematoma. Apixaban was discontinued and the patient was monitored for extension of the hematoma. After 2 days she was discharged home. Outpatient computed tomography 1 month later showed complete resolution of the rectus sheath hematoma. We recommend that clinicians become aware of the potential for rare and serious bleeding complications of anticoagulants and identify the need for early recognition and prompt management.

Clinical Application of Prothrombin Complex Concentrate in Blood Management in Patients

Management of patients receiving anticoagulants is a major factor in achieving better outcomes. Anticoagulant therapy may need to be discontinued or rapidly reversed before urgent surgery or invasive procedures. In these situations, treatment with concentrated vitamin K, fresh frozen plasma, and/or clotting factors can achieve more rapid anticoagulant reversal than can drug discontinuation alone. Activated prothrombin complex concentrate is used to treat hemophiliac patients with acquired factor VIII inhibitors. Nonactivated prothrombin complex concentrates are used for anticoagulant reversal. The concentrates are effective within minutes of dosing, providing a nearly immediate decrease in the international normalized ratio. The concentrates are lyophilized powders that can be quickly reconstituted, do not require ABO blood typing before use, and contain 25 times the concentration of vitamin K-dependent clotting factors compared with fresh frozen plasma. Studies suggest that the concentrates are associated with better clinical end points than is fresh frozen plasma.

Guidance for the practical management of the direct oral anticoagulants (DOACs) in VTE treatment

Venous thromboembolism (VTE) is a serious medical condition associated with significant morbidity and mortality, and an incidence that is expected to double in the next forty years. The advent of direct oral anticoagulants (DOACs) has catalyzed significant changes in the therapeutic landscape of VTE treatment. As such, it is imperative that clinicians become familiar with and appropriately implement new treatment paradigms. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance for VTE treatment with the DOACs. When possible, guidance statements are supported by existing published evidence and guidelines. In instances where evidence or guidelines are lacking, guidance statements represent the consensus opinion of all authors of this manuscript and are endorsed by the Board of Directors of the Anticoagulation Forum.

The authors of this manuscript first developed a list of pivotal practical questions related to real-world clinical scenarios involving the use of DOACs for VTE treatment. We then performed a PubMed search for topics and key words including, but not limited to, apixaban, antidote, bridging, cancer, care transitions, dabigatran, direct oral anticoagulant, deep vein thrombosis, edoxaban, interactions, measurement, perioperative, pregnancy, pulmonary embolism, reversal, rivaroxaban, switching, \thrombophilia, venous thromboembolism, and warfarin to answer these questions. Non- English publications and publications > 10 years old were excluded. In an effort to provide practical information about the use of DOACs for VTE treatment, answers to each question are provided in the form of guidance statements, with the intent of high utility and applicability for frontline clinicians across a multitude of care settings.

North American Thrombosis Forum, AF Action Initiative Consensus Document

The North American Thrombosis Forum Atrial Fibrillation Action Initiative consensus document is a comprehensive yet practical briefing document focusing on stroke and bleeding risk assessment in patients with atrial fibrillation, as well as recommendations regarding anticoagulation options and management. Despite the breadth of clinical trial data and guideline recommendation updates, many clinicians continue to struggle to synthesize the disparate information available. This problem slows the uptake and utilization of updated risk prediction tools and adoption of new oral anticoagulants. This document serves as a practical and educational reference for the entire medical community involved in the care of patients with atrial fibrillation.

In vitro reversal of supratherapeutic rivaroxaban levels with coagulation factor concentrates

BACKGROUND

A bleeding patient undergoing therapy with new oral anticoagulants is every clinician's nightmare as no specific reversal agent is available yet. This in vitro study investigated the effect of prothrombin complex concentrate (PCC), recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrate (aPCC) on supratherapeutic rivaroxaban concentrations using standard laboratory parameters (prothrombin time [PT], activated partial thromboplastin time [aPTT] and PT ratio) and thromboelastometry (clotting time [CT]).

MATERIALS AND METHODS

Blood samples from 10 healthy volunteers were collected and spiked with a supratherapeutic dose of rivaroxaban. Afterwards PCC, rFVIIa and aPCC were added in two doses. The laboratory parameters were measured and thromboelastometry was performed.

RESULTS

The addition of the reversal agents had the following statistically significant effects (all p<0.01): +25 IU/kg PCC: CT -15 s, aPTT +5 s; +50 IU/kg PCC: aPTT +11 s; +90 μg rFVIIa: CT -141 s; +25 IU/kg aPCC: CT -142 s, aPTT -9 s, PT ratio +14%, PT -10.5 s; +50 IU/kg aPCC: CT -118 s, aPTT -7 s, PT ratio +17%, PT -12.2 s.

DISCUSSION

rFVIIa and aPCC, but not PCC, appear to shorten coagulation times significantly in standard laboratory and thromboelastometry assays. These results need confirmation through evaluation of these agents in the clinical setting.

Limb-threatening Deep Venous Thrombosis Complicating Warfarin Reversal with Three-factor Prothrombin Complex Concentrate: A Case Report

BACKGROUND

Three- and four-factor prothrombin complex concentrates (PCC) are gaining popularity for acute reversal of vitamin K antagonist-associated bleeding. Although acute thrombosis after PCC administration has been described, it seems to be rare.

CASE REPORT

An 83-year-old woman on warfarin for history of deep venous thrombosis (DVT) presented to the Emergency Department with life-threatening gastrointestinal bleeding, requiring urgent PCC administration. After stabilization, she subsequently developed a new limb-threatening upper-extremity DVT. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: As PCC therapy gains popularity for reversal of anticoagulant-induced bleeding in urgent bleeding scenarios, the emergency physician must be aware of the complications of PCC administration, including new limb-threatening DVT.

Clinical impact and course of major bleeding with rivaroxaban and vitamin K antagonists

BACKGROUND

Rivaroxaban is a new oral anticoagulant (NOAC) that can be prescribed in a fixed dose, making regular monitoring and dose adjustments unnecessary. It has been proven to be safe and effective in comparison with enoxaparin/vitamin K antagonists (LMWH/VKA) for the (extended) treatment of venous thromboembolism in the EINSTEIN studies. Nevertheless, there is a need for information regarding the clinical impact of (major) bleeding events with NOACs such as rivaroxaban.

OBJECTIVES

A post-hoc analysis was performed to compare the severity of clinical presentation and subsequent clinical course of major bleeding with rivaroxaban vs. LMWH/VKA.

METHODS

Two investigators performed a blinded classification of major bleeding using a priori defined criteria. During the EINSTEIN studies, data concerning the clinical course and measures applied were prospectively collected for each major bleed.

RESULTS

Treatment with LMWH/VKA caused more major bleeding events (1.7%) than rivaroxaban (1.0%; hazard ratio, 0.54; 95% confidence interval [CI], 0.37-0.79). Major bleeding events during rivaroxaban therapy had a milder presentation (23% were adjudicated to the worst categories vs. 38% for LMWH/VKA; hazard ratio or HR, 0.35; 95% CI, 0.17-0.74; P = 0.0062). The clinical course was severe in 25% of all major bleeding events associated with rivaroxaban, compared with 33% of LMWH/VKA-associated bleeds (HR, 0.46; 95% CI, 0.22-0.96; P = 0.040).

CONCLUSIONS

Rivaroxaban-associated major bleeding events occurred less frequently, had a milder presentation and appeared to take a less severe clinical course compared with major bleeding with LMWH/VKA.

Management of anticoagulation in patients with acute gastrointestinal bleeding

Acute gastrointestinal bleeding represents the most common adverse event associated with the use of oral anticoagulant therapy. Due to increasing prescription of anticoagulants worldwide, gastroenterologists are more and more called to deal with bleeding patients taking these medications. Their management is challenging because several issues have to be taken into account, such as the severity of bleeding, the intensity of anticoagulation, the patient's thrombotic risk and endoscopy findings. The recent introduction into the marketplace of new direct oral anticoagulants, for whom specific reversal agents are still lacking, further contributes to make the decision-making process even more demanding. Available evidence on this topic is limited and practice guidelines by gastroenterology societies only marginally address key issues for clinicians, including when and how to reverse coagulopathy, the optimal timing of endoscopy and when and how to resume anticoagulation thereafter. The present paper reviews the evidence in the literature and provides practical algorithms to support clinicians in the management of patients on anticoagulants who present with acute gastrointestinal bleeding.

New oral anticoagulants - a practical guide

Oral direct inhibitors of thrombin and activated factor Xa are approved as new anticoagulant drugs. In contrast to vitamin K antagonists (VKA) and heparins, the new agents have single targets in the coagulation cascade and more predictable pharmacokinetics, but they lack validated and available antidotes. Unlike VKA, they do not require routine monitoring of coagulation. However, the measurement of their pharmacologic effects might be of value in selected patients. They interfere with the routine coagulation tests, which should be interpreted with caution. Specific tests exist and can be used in case of emergencies. Adequate supportive care and temporary removal of all antithrombotic agents constitute the basis for management of serious bleeding complications. The administration of coagulation factors, such as fresh frozen plasma, prothrombin complex concentrates or recombinant activated FVII, can benefit in life-threatening bleeding or emergency surgery. Specific antidotes for non-vitamin K oral anticoagulants are in clinical development.

This review aims at answering in a brief and simplified manner some clinical questions.

Emergency reversal of dabigatran for emergency surgery

An 80-year-old woman had the anticoagulant effect of dabigatran etexilate reversed using factor eight inhibitor bypassing activity (FEIBA) in order to facilitate emergency surgery for an incarcerated femoral hernia. She had atrial fibrillation was taking the anticoagulant for stroke prevention. That afternoon her international normalised ratio (INR) was 1.3 and activated partial thromboplastin time ratio (APPTr) was 2.17, having taken dabigatran that morning. 3000 units of FEIBA and 10 mg of vitamin K were administered and she was taken to theatre for emergency surgery. Surgery was successful, total blood loss was less than 100 mL and there were no complications. The following morning she had an INR of 1.1 and APPTr of 1.49. She made an uneventful postoperative recovery and was discharged home. There is a limited evidence base guiding practice in the clinical scenario described. The only controlled studies available are animal experiments.

Pulmonary embolism: current and new treatment options

BACKGROUND

Pulmonary embolism (PE) can be a life-threatening emergency. Accurate diagnostic techniques and patient-specific management strategies are necessary to ensure favorable clinical outcomes.

METHODS

Relevant guidelines, articles, reviews, and abstracts were identified using a narrative approach in PubMed/MEDLINE, Google Scholar, clinicaltrials.gov and nice.org.uk. English-language articles published in 2000-2014 were initially identified using the search terms: novel OAC, pulmonary embolism, venous thromboembolism, diagnosis, treatment, rivaroxaban, apixaban, dabigatran, and edoxaban. The initial literature search was supported by a 'snowballing' style literature search, and relevant articles were included based on a professional judgment of relevance.

SCOPE

We discuss the diagnosis of PE and the categorization of risk for subgroups, which may assist with making treatment decisions. We review current guidance on acute and long-term treatment, possible limitations of traditional anticoagulant therapy, and the development of direct oral anticoagulants, which may significantly alter the management of patients with PE. Finally, we discuss special considerations in high-risk and hard-to-treat subpopulations that may benefit from the improved benefit-risk profile offered by these newer agents.

CONCLUSIONS

The direct oral anticoagulants may overcome several of the limitations associated with traditional anticoagulant therapy, potentially improving the standard of care for PE patients, including high-risk and hard-to-manage subgroups.

Perioperative management of patients receiving new oral anticoagulants: an international survey

New oral anticoagulants (NOACs) are increasingly replacing standard anticoagulants. These new drugs have been recently introduced in clinical practice, and specific knowledge regarding preoperative interruption, anticoagulation assessment, and reversal therapies is needed. In this article, 3 main areas related to perioperative NOACs management are discussed: (1) physicians' knowledge, (2) current practices, and (3) perspectives to improve management of patients treated with NOACs.

Preventive strategies against bleeding due to nonvitamin K antagonist oral anticoagulants

Dabigatran etexilate (DE), rivaroxaban, and apixaban are nonvitamin K antagonist oral anticoagulants (NOACs) that have been compared in clinical trials with existing anticoagulants (warfarin and enoxaparin) in several indications for the prevention and treatment of thrombotic events. All NOACs presented bleeding events despite a careful selection and control of patients. Compared with warfarin, NOACs had a decreased risk of intracranial hemorrhage, and apixaban and DE (110 mg BID) had a decreased risk of major bleeding from any site. Rivaroxaban and DE showed an increased risk of major gastrointestinal bleeding compared with warfarin. Developing strategies to minimize the risk of bleeding is essential, as major bleedings are reported in clinical practice and specific antidotes are currently not available. In this paper, the following preventive approaches are reviewed: improvement of appropriate prescription, identification of modifiable bleeding risk factors, tailoring NOAC's dose, dealing with a missed dose as well as adhesion to switching, bridging and anesthetic procedures.

Management of anticoagulant-related intracranial hemorrhage: an evidence-based review

The increased use of anticoagulants for the prevention and treatment of thromboembolic diseases has led to a rising incidence of anticoagulant-related intracranial hemorrhage (AICH) in the aging western population. High mortality accompanies this form of hemorrhagic stroke, and significant and debilitating long-term consequences plague survivors. Although management guidelines for such hemorrhages are available for the older generation anticoagulants, they are still lacking for newer agents, which are becoming popular among physicians. Supportive care, including blood pressure control, and reversal of anticoagulation remain the cornerstone of acute management of AICH. Prothrombin complex concentrates are gaining popularity over fresh frozen plasma, and reversal agents for newer anticoagulation agents are being developed. Surgical interventions are options fraught with complications, and are decided on a case-by-case basis. Our current state of understanding of this condition and its management is insufficient. This deficit calls for more population-based studies and therapeutic trials to better evaluate risk factors for, and to prevent and treat AICH.

Perioperative management of patients on new oral anticoagulants

Background

New oral anticoagulants (NOACs) offer an alternative to warfarin for preventing stroke in patients with atrial fibrillation. NOACs are expected to replace warfarin and other vitamin K antagonists for most of their indications in the future. Knowledge of the use of NOACs in the perioperative period is important for optimal care.

Methods

Studies that reported on the use of NOACs were identified, focusing on evidence-based guidance relating to the perioperative period. PubMed was searched for relevant articles published between January 2000 and January 2014.

Results

The anticipated expanded clinical use of NOACs such as rivaroxaban (Xarelto™), apixaban (Eliquis™) and dabigatran (Pradaxa™) has the potential to simplify perioperative anticoagulant management because of fewer drug–drug interactions, rapid onset of action, predictable pharmacokinetics and relatively short half-lives. However, coagulation status cannot be monitored by international normalized ratio and no antidotes are currently available. In elective surgery, it is important to discontinue the use of NOACs, with special consideration of renal function as route of elimination. Guidelines for the management of bleeding complications in patients on NOACs are provided, and may be considered for trauma and emergency surgery. Haemodialysis could be considered for bleeding with use of dabigatran. Better options for reversal of the effects of NOACs when bleeding occurs may follow with novel drugs.

Conclusion

Management of NOACs in elective and emergency conditions requires knowledge of time of last intake of drug, current renal function and the planned procedure in order to assess the overall risk of bleeding. Currently no antidote exists to reverse the effects of these drugs.

The role of prothrombin complex concentrates in reversal of target specific anticoagulants

Over the past several years a new era for patients requiring anticoagulation has arrived. The approval of new target specific oral anticoagulants offers practitioners several advantages over traditionally used vitamin K antagonist agents including predictable pharmacokinetics, rapid onset of action, comparable efficacy and safety, all without the need for routine monitoring. Despite these benefits, hemorrhagic complicates are inevitable with any anticoagulation treatment. One of the major disadvantages of the new oral anticoagulants is lack of specific antidotes or reversal agents for patients with serious bleeding or need for urgent surgery. As use of the new target specific oral anticoagulants continues to increase, practitioners will need to understand both the pharmacodynamics and pharmacokinetic properties of the agents, as well as, the available literature with use of non-specific therapies to reverse anticoagulation. Four factor prothrombin complex concentrates have been available for several years in Europe, and recently became available in the United States with approval of Kcentra. These products have shown efficacy in reversing anticoagulation from vitamin K antagonists, however their usefulness with the new target specific oral anticoagulants is poorly understood. This article will review the properties of dabigatran, rivaroxaban and apixaban, as well as the limited literature available on the effectiveness of prothrombin complex concentrates in reversal of their anticoagulant effects. Additional studies are needed to more accurately define the role of prothrombin complex concentrates in patients with life threatening bleeding or who require emergent surgery, as current data is both limited and conflicting.

Pros and cons of new oral anticoagulants

The availability of new oral anticoagulants (NOACs) targeting either thrombin (dabigatran etexilate) or factor Xa (rivaroxaban and apixaban) for the prevention and treatment of thrombosis has been highly anticipated. NOACs have major pharmacologic advantages over vitamin K antagonists (eg, warfarin), including rapid onset/offset of action, few drug interactions, and predictable pharmacokinetics, eliminating the requirement for regular coagulation monitoring. Regulatory agencies have approved several NOACs for specific indications based on the results of clinical trials demonstrating efficacy and safety that are at least as good, if not better, than warfarin (for stroke prevention in atrial fibrillation and treatment and secondary prevention of venous thromboembolism) or low-molecular-weight heparin, which is injectable (for initial treatment of venous thromboembolism and thromboprophylaxis in patients undergoing hip or knee arthroplasty). However, the adoption of this new therapeutic class into clinical practice has been slower than expected due to several factors including concerns regarding medication adherence without laboratory monitoring, uncertainty about dosing in some patient populations (eg, renal dysfunction, marked extremes of body weight), and higher drug costs compared with warfarin. Other issues are the current absence of specific antidotes for NOACs and assays to measure drug levels at most centers. The indications for NOACs on the market will expand and at least one additional agent (edoxaban) will likely gain approval within the next 2 years. As practitioners gain familiarity with the drugs and healthcare systems adapt to their use, NOAC use will increase substantially over time. Warfarin, however, will continue to be an appropriate anticoagulant choice for many patients.

Recent pharmacological advances for treating venous thromboembolism: are we witnessing the demise of warfarin?

Vitamin K antagonists, such as warfarin, have been the mainstay in treatment and prophylaxis of venous thromboembolism. However, warfarin has many disadvantages including a narrow therapeutic window, numerous potential drug interactions, modulation of effect by alcohol and foods containing vitamin K and genetic variation in metabolism of warfarin, all of which contribute to the unpredictability of therapy. This has provided the impetus for developing new oral anticoagulants with a rapid onset of action, wide therapeutic window, predictable and reversible action, with few drug or dietary interactions, no requirement for routine coagulation monitoring or dose adjustment and acceptable cost. No single agent incorporates all these characteristics, but new factor Xa and direct thrombin inhibitors are being introduced into clinical practice that fulfil some of these aims. Here, we briefly discuss the current practice with its limitations and pitfalls, and then review important trials that have launched new oral anticoagulants into clinical practice.