Reversing anticoagulant effects of novel oral anticoagulants: role of ciraparantag, andexanet alfa, and idarucizumab

The methods for removal of direct oral anticoagulants and heparins to improve the monitoring of hemostasis: a narrative literature review

The assessment of hemostasis is necessary to make suitable decisions on the management of patients with thrombotic disorders. In some clinical situations, for example, during thrombophilia screening, the presence of anticoagulants in sample makes diagnosis impossible. Various elimination methods may overcome anticoagulant interference. DOAC-Stop, DOAC-Remove and DOAC Filter are available methods to remove direct oral anticoagulants in diagnostic tests, although there are still reports on their incomplete efficacy in several assays. The new antidotes for direct oral anticoagulants - idarucizumab and andexanet alfa - could be potentially useful, but have their drawbacks. The necessity to remove heparins is also arising as heparin contamination from central venous catheter or therapy with heparin disturbs the appropriate hemostasis assessment. Heparinase and polybrene are already present in commercial reagents but a fully-effective neutralizer is still a challenge for researchers, thus promising candidates remain in the research phase.

Costs and Healthcare Resource Utilization Associated with Idarucizumab or Andexanet Alfa Oral Anticoagulant Reversal in Patients Hospitalized with Life-Threatening Bleeds

Purpose: To assess costs and healthcare resource utilization (HCRU) associated with the use of idarucizumab for the reversal of dabigatran and andexanet alfa for the reversal of direct oral Factor Xa inhibitors. Methods: This retrospective study utilizing Premier Healthcare Database (PHD) included patients aged ≥18 years on direct oral anticoagulants (DOACs) who experienced life-threatening bleeds, discharged from the hospital during 5/1/2018–6/30/2019, and received idarucizumab or andexanet alfa. Inverse of treatment probability weighting (IPTW) method was used to balance patient and clinical characteristics between treatment cohorts. Results: Idarucizumab patients were older than andexanet alfa patients (median age 81 vs 77 years; p < 0.001), and less likely to experience intracranial hemorrhage (ICH) (37.1%vs 73.8%; p  =  0.001). After IPTW adjustment, idarucizumab patients incurred lower mean total hospital costs ($30,413  ±  $33,028 vs $44,477  ±  $30,036; p < 0.001),and mean intensive care unit (ICU) cost ($25,114  ±  $30,433 vs $43,484  ±  $29,335; p < 0.001). Conclusions: Anticoagulant reversal therapy with idarucizumab was associated with significantly lower adjusted mean total hospital and ICU costs compared with andexanet alfa. However, a higher prevalence of ICH bleeds was noted in the andexanet alfa group. Trial Registration: Not applicable.

Direct oral anticoagulants: a review on the current role and scope of reversal agents

New guideline recommendations prefer direct oral anticoagulants (DOACs) over warfarin in DOAC-eligible patients with atrial fibrillation and patients with venous thromboembolism. As expected with all antithrombotic agents, there is an associated increased risk of bleeding complications in patients receiving DOACs that can be attributed to the DOAC itself, or other issues such as acute trauma, invasive procedures, or underlying comorbidities. For the majority of severe bleeding events, the widespread approach is to withdraw the DOAC, then provide supportive measures and "watchful waiting" with the expectation that the bleeding event will resolve with time. However, urgent reversal of anticoagulation may be advantageous in patients with serious or life-threatening bleeding or in those requiring urgent surgery or procedures. Until recently, the lack of specific reversal agents, has affected the uptake of these agents in clinical practice despite a safer profile compared to warfarin in clinical trials. In cases of life-threatening or uncontrolled bleeding or when patients require emergency surgery or urgent procedures, idarucizumab has been recently approved for reversal of anticoagulation in dabigatran-treated patients and andexanet alfa for factor Xa inhibitor-treated treated patients. The current review summarizes the current clinical evidence and scope of these agents with the potential impact on DOAC use in clinical practice.

Marine Antithrombotics

Thrombosis remains a prime reason of mortality worldwide. With the available antithrombotic drugs, bleeding remains the major downside of current treatments. This raises a clinical concern for all patients undergoing antithrombotic therapy. Novel antithrombotics from marine sources offer a promising therapeutic alternative to this pathology. However, for any potential new molecule to be introduced as a real alternative to existing drugs, the exhibition of comparable anticoagulant potential with minimal off-target effects must be achieved. The relevance of marine antithrombotics, particularly sulfated polysaccharides, is largely due to their unique mechanisms of action and lack of bleeding. There have been many investigations in the field and, in recent years, results have confirmed the role of potential marine molecules as alternative antithrombotics. Nonetheless, further clinical studies are required. This review covers the core of the data available so far regarding the science of marine molecules with potential medical applications to treat thrombosis. After a general discussion about the major biochemical steps involved in this pathology, we discuss the key structural and biomedical aspects of marine molecules of both low and high molecular weight endowed with antithrombotic/anticoagulant properties.

Multicenter experience with photoselective vaporization of the prostate on men taking novel oral anticoagulants

Objective

Photoselective vaporization of the prostate (PVP) is a widely performed surgical procedure for benign prostatic obstruction. This approach has become particular favoured for men on anti-platelet and anticoagulation agents such as clopidogrel and warfarin but there is minimal published experience in the setting of novel oral anticoagulants (NOACs). This study was to examine the perioperative outcomes in men on NOACs undergoing PVP, with particular reference to perioperative morbidity.

Methods

A retrospective analysis of PVP datasets was undertaken from three centres in Sydney (Australia), Toulouse (France) and Boston (USA). Subjects who had been treated whilst on NOACs without discontinuation or bridging were identified. Perioperative outcomes and treatment parameters were examined and morbidity recorded according to Clavien-Dindo (CD) classification.

Results

There were a total of 20 subjects who had undergone PVP whilst NOACs had been continued during the perioperative period. The mean age was 77±6.5 years. The mean prostate volume, energy utilization and vaporisation time was 94±56 mL, 301±211 kJ, and 35±21 min respectively. The mean postoperative duration of catheterization and duration of hospitalization was 2.2±2.4 days and 2.4±2.4 days respectively. There was a single episode of urinary tract infection and four subjects required re-catheterisation for non-hematuric retentions.

Conclusions

This study supports the safety of men on NOACs undergoing PVP. Whilst this study represents the largest experience of PVP in these men, larger studies are necessary to confirm the safety of PVP in this group of men undergoing BPH-related surgery.

Assay-Based Differentiation in the Neutralization Profile of Unfractionated Heparin, Enoxaparin, and Fondaparinux by Andexanet Alfa

Andexanet alfa is a recombinant factor Xa decoy protein, designed to reverse bleeding associated with oral anti-Xa agents. Andexanet alfa is also reported to neutralize the effects of heparin-related drugs. This study focused on the neutralization profiles of unfractionated heparin (UFH), enoxaparin, and, a chemically synthetic pentasaccharide, fondaparinux by andexanet alfa. Whole blood clotting studies were carried out using thromboelastography (TEG) and activated clotting time (ACT). The anticoagulant profile of UFH, enoxaparin, and fondaparinux was studied using the activated partial thromboplastin time (aPTT), thrombin time (TT), and amidolytic anti-Xa, and anti-IIa methods. Thrombin generation inhibition was studied using the calibrated automated thrombogram system. Reversal of each of these agents was studied by supplementing andexanet alfa at 100 µg/mL. In the TEG, andexanet alfa produced almost a complete reversal of the anticoagulant effects of UFH and enoxaparin; however, it augmented the effects of fondaparinux. In the ACT, aPTT, and TT, UFH produced strong anticoagulant effects that were almost completely neutralized by andexanet alfa. Enoxaparin produced milder anticoagulant responses that were partially neutralized, whereas fondaparinux did not produce any sizeable effects. In the anti-Xa and anti-IIa assays, UFH exhibited partial neutralization whereas enoxaparin and fondaparinux did not show any neutralization. All agents produced varying degrees of the inhibition of thrombin generation, which were differentially neutralized by andexanet alfa. These results indicate that andexanet alfa is capable of differentially neutralizing anticoagulant and antiprotease effects of UFH and enoxaparin in an assay-dependent manner. However, andexanet alfa is incapable of neutralizing the anti-Xa effects of fondaparinux.

An Update on the Reversal of Non-Vitamin K Antagonist Oral Anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs) include thrombin inhibitor dabigatran and coagulation factor Xa inhibitors rivaroxaban, apixaban, edoxaban, and betrixaban. NOACs have several benefits over warfarin, including faster time to the achieve effect, rapid onset of action, fewer documented food and drug interactions, lack of need for routine INR monitoring, and improved patient satisfaction. Local hemostatic measures, supportive care, and withholding the next NOAC dose are usually sufficient to achieve hemostasis among patients presenting with minor bleeding. The administration of reversal agents should be considered in patients on NOAC's with major bleeding manifestations (life-threatening bleeding, or major uncontrolled bleeding), or those who require rapid anticoagulant reversal for an emergent surgical procedure. The Food and Drug Administration (FDA) has approved two reversal agents for NOACs: idarucizumab for dabigatran and andexanet alfa for apixaban and rivaroxaban. The American College of Cardiology (ACC), American Heart Association (AHA), and Heart Rhythm Society (HRS) have released an updated guideline for the management of patients with atrial fibrillation that provides indications for the use of these reversal agents. In addition, the final results of the ANNEXA-4 study that evaluated the efficacy and safety of andexanet alfa were recently published. Several agents are in different phases of clinical trials, and among them, ciraparantag has shown promising results. However, their higher cost and limited availability remains a concern. Here, we provide a brief review of the available reversal agents for NOACs (nonspecific and specific), recent updates on reversal strategies, lab parameters (including point-of-care tests), NOAC resumption, and agents in development.

Direct-Acting Oral Anticoagulants and Their Reversal Agents-An Update

Background: Over the last ten years, a new class of drugs, known as the direct-acting oral anticoagulants (DOACs), have emerged at the forefront of anticoagulation therapy. Like the older generation anticoagulants, DOACs require specific reversal agents in cases of life-threatening bleeding or the need for high-risk surgery. Methods: Published literature was searched, and information extracted to provide an update on DOACS and their reversal agents. Results: The DOACs include the direct thrombin inhibitor—dabigatran, and the factor Xa inhibitors—rivaroxaban, apixaban, edoxaban, and betrixaban. These DOACs all have a rapid onset of action and each has a predictable therapeutic response requiring no monitoring, unlike the older anticoagulants, such as warfarin. Two reversal agents have been approved within the last five years: idarucizumab for the reversal of dabigatran, and andexanet alfa for the reversal of rivaroxaban and apixaban. Additionally, ciraparantag, a potential “universal” reversal agent, is currently under clinical development. Conclusions: A new generation of anticoagulants, the DOACs, and their reversal agents, are gaining prominence in clinical practice, having demonstrated superior efficacy and safety profiles. They are poised to replace traditional anticoagulants including warfarin.

Current status of oral anticoagulant reversal strategies: a review

Utilization of direct oral anticoagulants (DOAC) have steadily increased since their approval and are now recommended over warfarin for both stroke prevention in nonvalvular atrial fibrillation and treatment of venous thromboembolism (VTE). With increased DOAC use, the number of major bleeding events requiring medical intervention will continue to rise. Until 2015, warfarin maintained an advantage as the only oral anticoagulant with a specific reversal agent. Since then, idarucizumab has been approved for dabigatran reversal and recently, andexanet alfa was granted approval for the reversal of apixaban or rivaroxaban in patients with life-threatening or uncontrolled bleeding events. Due to the manufacturing practices required to yield these reversal therapies, they are available at high cost to hospital systems and as a result, have been met with resistance. Data exists describing both prothrombin complex concentrates (PCC) and andexanet alfa for DOAC reversal, however, without head-to-head comparison. Until future studies are available, current literature must be critically evaluated to aid in the clinical decision-making process of how to treat patients with life-threatening DOAC-related bleeding.

An update on neurocritical care for intracerebral hemorrhage

Introduction: Intracerebral hemorrhage remains one of the leading causes of death and disability worldwide with few established interventions that improve neurologic outcome. Research dedicated to better understanding and treating hemorrhagic strokes has multiplied in the past decade. Areas Covered: This review aims to discuss the current landscape of management of intracerebral hemorrhage in a critical care setting and provide updates regarding developments in therapeutic interventions and targets. PubMed was utilized to review recent literature, with a focus on large trials and meta-analyses, which have shaped current practice. Published committee guidelines were also included. A focus was placed on research published after 2015 in an effort to supplement previous reviews included in this publication. Expert Opinion: Literature pertaining to ICH management has allowed for a greater understanding of ineffective strategies as opposed to those of benefit. Despite this, mortality has improved worldwide, which may be the result of growing research efforts. Areas of future research that will impact mortality and improve neurologic outcomes include prevention of hematoma expansion, optimization of blood pressure targets, effective coagulopathy reversal, and minimally invasive surgical techniques to reduce hematoma burden.

Comparison of reversal activity and mechanism of action of UHRA, andexanet, and PER977 on heparin and oral FXa inhibitors

Anticoagulants such as unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), fondaparinux, and direct oral anticoagulants (DOACs) targeting thrombin (IIa) or factor Xa (FXa) are widely used in prevention and treatment of thromboembolic disorders. However, anticoagulant-associated bleeding is a concern that demands monitoring and neutralization. Protamine, the UFH antidote, has limitations, while there is no antidote available for certain direct FXa inhibitors. Improved antidotes in development include UHRA (Universal Heparin Reversal Agent) for all heparin anticoagulants; andexanet alfa (andexanet), a recombinant antidote for both direct FXa inhibitors and LMWHs; and ciraparantag (PER977), a small-molecule antidote for UFH, LMWHs, and certain DOACs. The binding affinities of these antidotes for their presumed anticoagulant targets have not been compared. Here, isothermal titration calorimetry (ITC) was used to determine the affinity of each antidote for its putative targets. Clotting and chromogenic FXa assays were used to characterize neutralization activity, and electron microscopy was used to visualize the effect of each antidote on clot morphology in the absence or presence of anticoagulant. ITC confirmed binding of UHRA to all heparins, and binding of andexanet to edoxaban and rivaroxaban, and to the antithrombin-enoxaparin complex. PER977 was found to bind heparins weakly, but not the direct FXa inhibitors studied. For UHRA and andexanet, an affinity at or below the micromolar level was found to correlate with neutralization activity, while no reversal activity was observed for the PER977/anticoagulant systems. Standard metrics of clot structure were found to correlate weakly with PER977's activity. This is the first study comparing 3 antidotes in development, with each exerting activity through a distinct mechanism.

Novel reversal agents and laboratory evaluation for direct-acting oral anticoagulants (DOAC): An update

Novel oral anticoagulants (NOACs) are no longer "novel" but their reversal agents definitely are. Although NOACs enjoy high clinical efficacy, monitoring and reversal of their effect is a challenge which this review attempts to surmount. Ideally, for NOAC activity measurement, specific anti-Factor IIa levels and anti -Factor Xa levels should be monitored (chromogenic assays), but such tests are not readily available. Modifications of the existing coagulation tests catering to this unmet need for quantification of DOAC activity have been reviewed. The available United States Food and Drug Administration (FDA) approved reversal agents, idarucizumab for dabigatrin and andexanet alfa for anti-Xa direct acting oral anticoagulants have given promising results but are prohibitively priced. Medline, Embase, and Scopus databases were thoroughly searched for clinical trials on laboratory investigations and specific as well as non-specific reversal-agents for DOACs.

Management of Non-tumoral Portal Vein Thrombosis in Patients with Cirrhosis

Non-tumoral portal vein thrombosis (PVT) remains a highly relevant topic in the field of hepatology and liver transplantation with much surrounding controversy. Although multiple studies have shown that PVT is associated with adverse outcomes with increased morbidity and mortality rates, others have not reported the same clinical impact of PVT, arguing rather that incident PVT reflects worsening portal hypertension and the natural history of the disease. Despite this uncertainly, PVT is a dilemma facing the clinician on a daily basis often requiring a multidisciplinary team-based approach between hepatologists, transplant surgeons, interventional radiologists and hematologists. In this review, the authors provide a summary of the evidence supporting best clinical practices in the management of non-tumoral PVT in patients with cirrhosis.

Direct oral anticoagulants for treatment of deep vein thrombosis: overview of systematic reviews

A number of limitations of standard therapy with warfarin for deep vein thrombosis (DVT) have been established. This overview of systematic reviews presents the baseline results for efficacy and safety of the new direct oral anticoagulants (DOACs) thrombin inhibitors, and activated factor X (Xa) inhibitors in patients with DVT. Searches were run on PubMed and the Cochrane Database of Systematic Reviews. Twenty-three studies were retrieved, and one systematic review was judged eligible. This review scored maximum according to AMSTAR criteria and included 7,596 patients for analysis of thrombin inhibitors and 16,356 patients for analysis of factor Xa inhibitors. The results of the meta-analysis indicate that DOACs are similar for DVT treatment when compared to standard treatment with warfarin. The incidence of major bleeding is somewhat lower in patients treated with factor Xa inhibitors and similar to standard therapy when treated with direct thrombin inhibitors.

Andexanet Alfa: First Global Approval

Intravenous andexanet alfa [coagulation factor Xa (recombinant), inactivated-zhzo; Andexxa^®] is a first-in-class recombinant modified factor Xa protein that has been developed by Portola Pharmaceuticals as a universal antidote to reverse anticoagulant effects of direct or indirect factor Xa inhibitors. In May 2018, andexanet alfa received its first global approval in the USA for use in patients treated with rivaroxaban and apixaban, when reversal of anticoagulant effects is required in life-threatening or uncontrolled bleeding. Intravenous andexanet alfa is under regulatory review in the EU and is undergoing clinical development in Japan. This article summarizes the milestones in the development of andexanet alfa leading to this first global approval for reversing anticoagulation of rivaroxaban and apixaban in adults.

Portal vein thrombosis in cirrhotic patients - it is always the small pieces that make the big picture

Portal vein thrombosis (PVT) is a frequent and serious complication in patients with liver cirrhosis (LC). Recently, a new classification of PVT was proposed, although the functional component was not completed included. The status of liver disease (compensated/decompensated) should be added to this classification. Reduced portal flow velocity and the acquired hypercoagulable status associated with LC are the main risk factors for PVT development, although endothelial dysfunction may play an important role that needs to be further evaluated. The European Association for the Study of the Liver and the American Association for the Study of Liver Disease recommend that the anticoagulant treatment should be consider in cirrhotic patients with PVT. Low molecular weight heparin and vitamin K antagonists proved their efficacy and relatively safety in PVT treatment, although in addition to recanalization rates, more complex end-points such as mortality and decompensation rate should be evaluated. The new oral anticoagulant therapies offers the advantage of oral administration in the absence of laboratory monitoring, however, there are a few reports regarding their use in cirrhotic patients, most of them referring to compensated isolated cases. Transjugular intrahepatic portosystemic shunt could be an alternative if thrombosis progresses despite anticoagulatant therapy and/or when PVT is associated with portal hypertension complications. The aim of this editorial is to discuss the different aspects of pathophysiology, clinical relevance, diagnosis and management of PVT in patients with LC.

Prothrombin complex concentrate versus placebo, no intervention, or other interventions in critically bleeding patients associated with oral anticoagulant administration: a protocol for a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Acute critical bleeding is one of the most feared complications during treatment with oral anticoagulating agents. As more patients undergo treatment with anticoagulating agents, critically bleeding episodes in patients with vitamin K antagonists, thrombin inhibitor, or factor Xa inhibitor-inducted coagulopathy will be encountered frequently by physicians. Hence, an effective treatment capable of reversing the iatrogenic coagulopathy in the acute setting is needed. In randomised clinical trials and observational studies, prothrombin complex concentrate has been reported to be superior to other acute interventions, and many guidelines recommend prothrombin complex concentrate in treatment of critically bleeding patients. The aim of this systematic review is to synthesise the evidence of the effects of prothrombin complex concentrate compared with placebo, no intervention, or other treatment options in critically bleeding patients treated with oral anticoagulants.

METHODS/DESIGN

A comprehensive search for relevant published literature will be undertaken in Cochrane Central Register of Controlled Trials, MEDLINE, Embase, WHO International Clinical Trials Registry Platform, Science Citation Index, regulatory databases, and trial registers. We will include randomised clinical trials comparing prothrombin complex concentrate versus placebo, no intervention, or other interventions in critically bleeding patients with oral anticoagulant-induced coagulopathy. Data extraction and risk of bias assessment will be handled by two independent review authors. Meta-analysis will be performed as recommended by Cochrane Handbook for Systematic Reviews of Interventions, bias will be assessed with domains, and trial sequential analysis will be conducted to control random errors. Certainty will be assessed by GRADE.

DISCUSSION

As critical bleeding in patients treated with oral anticoagulants is an increasing problem, an up-to-date systematic review evaluating the benefits and harms of prothrombin complex concentrate is urgently needed. It is the hope that this review will be able to guide best practice in treatment and clinical research of these critically bleeding patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018084371.

Newer Oral Anticoagulants in the Treatment of Acute Portal Vein Thrombosis in Patients with and without Cirrhosis

BACKGROUND

Newer oral anticoagulants (NOACs) are being utilized increasingly for the treatment of venous thromboembolism (VTE). NOAC use is the standard of care for stroke prophylaxis in nonvalvular atrial fibrillation and treatment of acute VTE involving extremities and pulmonary embolism. In contrast, most guidelines in the literature support the treatment of acute portal vein thrombosis (PVT) with low molecular weight heparin (LMWH) and vitamin K antagonists (VKA). Literature evaluating NOAC use in the treatment of acute portal vein thrombosis is sparse. This review focuses on the safety and efficacy of the use of NOACs in the treatment of acute PVT in patients, with or without concomitant cirrhosis, based on the most recent data available in the current literature.

METHODS

A systematic review was conducted through a series of advanced searches in the following medical databases: PubMed, BioMed Central, Cochrane, and Google Scholar. Keywords utilized were as follows: NOAC, DOAC (direct oral anticoagulants), portal vein thrombosis, rivaroxaban, apixaban, dabigatran, and edoxaban. Articles related to newer anticoagulant use in patients with portal vein thrombosis were included.

RESULTS

The adverse events, including bleeding events (major and minor) and the failure of anticoagulation (propagation of thrombus or recurrence of PVT), are similar between the NOACs and traditional anticoagulants for the treatment of acute PVT, irrespective of the presence of cirrhosis.

CONCLUSIONS

Newer oral anticoagulants are safe and efficacious alternatives to traditional anticoagulation with low molecular weight heparin and vitamin K antagonists in the treatment of acute portal vein thrombosis with or without cirrhosis.

Severe haematuria of lower urinary tract origin with low dose dabigatran use in three Indian elderly patients: unresolved issues in the safety of novel oral anticoagulants

Dabigatran is a newer oral direct thrombin inhibitor approved by the United States Food and Drug Administration and the European Medicines Agency (EMA). The proper dosage of the drug, the potential for adverse drug reactions and the nature of bleeds with use of this drug as with other novel oral anticoagulants (NOACs), in the elderly population are still areas of uncertainty. Despite the existence of a specific antibody, idarucizumab which is an antidote to dabigatran toxicity, management of dabigatran-induced bleeds is an undefined area especially in resource constrained settings. We report severe haematuria with dabigatran in three elderly Indian patients at the lowest recommended therapeutic dose and explore these grey zones in dabigatran therapy.

Engineering a simple lateral flow device for animal blood coagulation monitoring

Increasing numbers of animals are diagnosed with thromboembolism, requiring anticoagulation treatment to prevent thrombotic events. Frequent and periodic coagulation monitoring is critical to ensure treatment effectiveness and patient safety by limiting blood coagulation ability within the desired therapeutic range. Point-of-care diagnostics is an ideal candidate for frequent coagulation monitoring due to rapid test results and no need for laboratory setting. This article reports the first utilization of no-reaction lateral flow assay (nrLFA) device for simple and low-cost animal blood coagulation monitoring in resource-limited setting. The nrLFA device consists of sample pad, analytical membrane and wicking pad, without conjugate pad, reagent printing or membrane drying. Citrated and heparinized animal blood were utilized to mimic different blood coagulation abilities in vitro by adding reversal agents CaCl2 and protamine sulfate. The travel distance of red blood cells (RBCs) on the nrLFA after a pre-determined test time serves as endpoint marker. Upon adding 500 mM CaCl2 solution to citrated bovine, canine, rabbit and equine blood, the average travel distance decreases from 10.9 to 9.4 mm, 8.8 to 5.7 mm, 12.6 to 9 mm, and 15.3 to 11.3 mm, respectively. For heparinized bovine and rabbit blood, the average distance decreases from 14.5 to 11.4 mm and from 9.8 to 7.2 mm, respectively, when adding 300 mg/l protamine sulfate solution. The effect of hematocrit on RBC travel distance in the nrLFA was also investigated. The nrLFA device will potentially improve treatment efficiency, patient safety, quality of life, and satisfaction for both animal patients and their owners.

Reversal Agents in the Era of NOACs

The incidence and prevalence of atrial fibrillation (AF) is expected to more than double between 2010 and 2030. Accordingly, the use of non-vitamin K oral anticoagulant (NOAC) agents for thromboembolic stroke prevention is anticipated to increase. The development of effective and safe antidotes is needed to address the unmet need for rapid anticoagulation reversal. The immediate role for these novel antidotes is for reversal of NOAC activity in life threatening bleeding and urgent surgical intervention. In addition, reversal agents may play an important role in simplifying bridging protocols in the peri-procedural period for catheter ablation of AF and elective surgery. Currently, novel reversal agents are either decoy drug receptors or small molecule non-specific anticoagulant activity inhibitors. These agents are at various stages of FDA investigation and approval, with emerging prospective data for safety and efficacy. The purpose of this review is to outline the currently developed NOAC molecular antagonists, their potential clinical roles and future directions.

Medication Reviews by a Clinical Pharmacist at an Irish University Teaching Hospital

Purpose: Pharmacist-led medication reviews in hospitals have shown improvement in patient outcomes. The aim of this study is to describe the prevalence and nature of pharmacist interventions (PIs) following a medication review in an Irish teaching hospital. Methods: PIs were recorded over a six-month period in 2015. PIs were assessed by a panel of healthcare professionals (n = 5) to estimate the potential of adverse drug events (ADEs). Descriptive statistics were used for the variables and the chi square test for independence was used to analyse for any association between the variables. Results: Of the 1216 patients (55.8% female; median age 68 years (interquartile range 24 years)) who received a medication review, 313 interventions were identified in 213 patients. 412 medicines were associated with PIs, of which drugs for obstructive airway disease (n = 82), analgesics (n = 56), and antibacterial products for systemic use (n = 50) were the most prevalent. A statistically significant association was found between PI and patient’s age ≥65 years (p = 0.000), as well as female gender (p = 0.037). A total of 60.7% of the PIs had a medium or high likelihood of causing an ADE. Conclusion: Pharmacist-led medication review in a hospital setting prevented ADEs. Patients ≥65 years of age and female patients benefited the most from the interventions.

New horizons in anticoagulation: Direct oral anticoagulants and their implications in oral surgery

BACKGROUND

Thrombotic disorders remain a leading cause of death in the Western World. For decades, vitamin K antagonists used in the prevention of this pathology, such as warfarin or sintrom, were the only oral agents available for long-term anticoagulation, in spite of their disadvantages.

MATERIAL AND METHODS

An electronic database search was carried out on MedLine and The Cochrane Library Plus, without restrictions on the type of study nor dates, in English and Spanish. Abstracts were reviewed, and complete articles if necessary, considering all articles that included recommendations on DOACs and oral surgery.

RESULTS

In recent years, the so-called "new oral anticoagulants" have been introduced in clinical practice to treat those patients whose medical conditions require long-term anticoagulant treatment, replacing traditional oral anticoagulants.

CONCLUSIONS

The new oral anticoagulants represent new therapeutic options, with a number of advantages such as poor interaction with food, minor drug interactions, and do not require periodic dose adjustments or routine controls. The purpose of this review is to establish an update on the new oral anticoagulants: Dabigatran, Rivarozaban, Apixaban and Edoxaban.

New Anticoagulants for the Prevention and Treatment of Venous Thromboembolism

Anticoagulant drugs, like vitamin K antagonists and heparin, have been the mainstay for the treatment and prevention of venous thromboembolic disease for many years. Although effective if appropriately used, traditional anticoagulants have several limitations such as unpredictable pharmacologic and pharmacokinetic responses and various adverse effects including serious bleeding complications. New oral anticoagulants have recently emerged as an alternative because of their rapid onset/offset of action, predictable linear dose-response relationships and fewer drug interactions. However, they are still associated with problems such as bleeding, lack of reversal agents and standard laboratory monitoring. In an attempt to overcome these drawbacks, key steps of the hemostatic pathway are investigated as targets for anticoagulation. Here we reviewed the traditional and new anticoagulants with respect to their targets in the coagulation cascade, along with their therapeutic advantages and disadvantages. In addition, investigational anticoagulant drugs currently in the development stages were introduced.

First Reported Case of Hemopericardium Related to Dabigatran Use Reversed by New Antidote Idarucizumab

Dabigatran, the first novel oral anticoagulant (NOAC) with a reversal agent, heralded a paradigm shift in the treatment of nonvalvular atrial fibrillation. The potential for life-threatening hemorrhagic events with the use of NOACs has been highly debated since the effectiveness of reversal agents such as idarucizumab is based primarily on pharmacologic data. It is known that cancer patients are at an increased risk of bleeding with anticoagulation, though specific studies demonstrating the risks or efficacy of NOACs in this population are lacking. We provide the first report of hemopericardium resulting in multiorgan failure related to dabigatran use that was successfully reversed by idarucizumab in a man with prostate cancer on chemotherapy.

Dental management of patients taking novel oral anticoagulants (NOAs): Dabigatran

Background

A new group of oral anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban) with clear advantages over classic dicoumarin oral anticoagulants (warfarin and acenocoumarol) has been developed in recent years. Patients being treated with oral anticoagulants are at higher risk for bleeding when undergoing dental treatments.

Material and Methods

A literature search was conducted through April 2016 for publications in the ISI Web of Knowledge, PubMed and Cochrane Library using the keywords “dabigatran”, “rivaroxaban”, “apixaban”, “edoxaban”, “new oral anticoagulants”, “novel oral anticoagulants”, “bleeding” and “dental treatment”.

Results

There is no need for regular coagulation monitoring of patients on dabigatran therapy. Whether or not to temporarily discontinue dabigatran must be assessed according to the bleeding risk involved in the dental procedure to be performed.

Conclusions

The number of patients under treatment with new oral anticoagulants will increase in the coming years. It is essential to know about the pharmacokinetics and pharmacodynamics of new oral anticoagulants and about their interactions with other drugs. It is necessary to develop clinical guidelines for the perioperative and postoperative management of these new oral anticoagulants in oral surgical procedures, and to carefully evaluate the bleeding risk of dental treatment, as well as the thrombotic risk of suppressing the new oral anticoagulant.

Key words:Dabigatran, rivaroxaban, apixaban, edoxaban, novel oral anticoagulants, bleeding.

Antiplatelet and Anticoagulant Therapies for Prevention of Ischemic Stroke

Ischemic stroke represents one of the leading causes of death and disability in both the United States and abroad, particularly for patients with prior ischemic stroke or transient ischemic attack (TIA). A quintessential aspect of secondary stroke prevention is the use of different pharmacological agents, mainly antiplatelets and anticoagulants. Antiplatelets and anticoagulants exhibit their effect by blocking the activation pathways of platelets and the coagulation cascade, respectively. Clinical trials have demonstrated the safety and efficacy of antiplatelets for noncardioembolic stroke prevention, while anticoagulants are more often used for cardioembolic stroke prevention. Commonly used antiplatelets include aspirin, clopidogrel, and aggrenox (aspirin plus extended-release dipyridamole). Furthermore, commonly used anticoagulants include warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban. Each of these drugs has a unique mechanism of action, and they share some common adverse events such as gastrointestinal bleeding and intracranial hemorrhage in more serious cases. Consequently, physicians should carefully assess the benefits and risks of using different antiplatelet or anticoagulant therapies when managing patients with previous ischemic stroke or TIA. This review discuses the published literature on major clinical trials assessing the efficacy of different antiplatelet and anticoagulant drugs under varying circumstances and the subsequent guidelines that have been developed by the American Heart Association/American Stroke Association. Additionally, the role of imaging in stroke prevention is discussed.

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.