Targeted Anti-Anticoagulants

Clinical Care Pathway and Management of Major Bleeding Associated with Nonvitamin K Antagonist Oral Anticoagulants: A Modified Delphi Consensus from Saudi Arabia and UAE

Background

The nonvitamin K antagonist oral anticoagulants (NOACs) have become the mainstay anticoagulation therapy for patients requiring oral anticoagulants (OACs) in the Gulf Council Cooperation (GCC) countries. The frequency of NOAC-associated major bleeding is expected to increase in the Emergency Department (ED). Nonetheless, we still lack local guidelines and recommendations for bleeding management in the region. The present Delphi-based consensus aims to establish a standardized and evidence-based clinical care pathway for managing NOAC-associated major bleeding in the Kingdom of Saudi Arabia (KSA) and the United Arab Emirates (UAE).

Methods

We adopted a three-step modified Delphi method to develop evidence-based recommendations through two voting rounds and an advisory meeting between the two rounds. A panel of 11 experts from the KSA and UAE participated in the consensus development.

Results

Twenty-eight statements reached the consensus level. These statements addressed key aspects of managing major bleeding events associated with NOACs, including the increased use of NOAC in clinical practice, clinical care pathways, and treatment options.

Conclusion

The present Delphi consensus provides evidence-based recommendations and protocols for the management of NOAC-associated bleeding in the region. Patients with major DOAC-induced bleeding should be referred to a well-equipped ED with standardized management protocols. A multidisciplinary approach is recommended for establishing the association between NOAC use and major bleeding. Treating physicians should have prompt access to specific reversal agents to optimize patient outcomes. Real-world evidence and national guidelines are needed to aid all stakeholders involved in NOAC-induced bleeding management.

Practical issues in measuring the anticoagulant effect of direct oral anticoagulants

The classical oral anticoagulants are increasingly being replaced in clinical practice by new antithrombotic drugs, which act by enabling direct inhibition of coagulation factor IIa (FIIa) or factor Xa (FXa). These drugs have multiple acronyms, including NOACs (new, non-vitamin K antagonist) or DOACs (direct oral anticoagulants), and currently include dabigatran (FIIa inhibitor), and rivaroxaban, apixaban, and edoxaban (FXa inhibitors). These drugs are approved for stroke prevention in patients with non-valvular atrial fibrillation and the prevention and treatment of venous thromboembolism. The "mantra" that DOACs do not require laboratory monitoring is not entirely correct because laboratory testing for drug effects is needed in many situations, because they influence hemostasis tests and in situations in which urgent measurement of DOACs is required. This should be very important to consider in the clinical situation for numbers of indications and increasing numbers of patients on DOACs therapy. The main aim of this article is to provide practical issues to general laboratory testing for DOACs, as well as to help avoid diagnostic errors associated with hemostasis testing. The assays for DOAC quantification must be available in medical centers on a whole day basis, to facilitate optimal drug management in conditions when things go wrong or in urgent cases of immediate reversal of anticoagulation or appropriate administration of a specific antidote.

International Normalized Ratio as a Screening Test for Assessment of Anticoagulant Activity for Patients Treated With Rivaroxaban or Apixaban: A Pilot Study

Introduction: In patients treated with direct oral anti activated factor X (anti-FXa) anticoagulants such as apixaban and rivaroxaban, there are several emergency and non-emergency conditions in which anticoagulation activity should be measured. The validity of the common global clotting tests, prothrombin time and international normalized ratio (PT/INR) for determination of blood levels of these drugs, has been widely investigated. As the anticoagulation activity evaluation “calibrated anti-FXa” of these drugs is relatively more expensive and less available, we aimed to build a prediction model for anticoagulation activity assessment based on INR values.

Methods and Findings: One hundred sixty samples from 80 hospitalized patients treated with apixaban or rivaroxaban were tested using PT/INR and Anti-FXa chromogenic assay. Two blood samples, trough and peak, were collected from each subject. Participants were randomly divided into two equal groups. One group (n = 40) was used to build the model, which was validated by the second group (n = 40). There was a strong correlation between anti-FXa concentrations and INR in rivaroxaban treated patients (r = 0.899, p < 0.001). Therefore, we were able to build a formula for rivaroxaban patient group which reliably represent the relationship between these two parameters. The correlation in apixaban treated patients was less predictive (r = 0.798, p < 0.001) and the formula suggested could not be validated.

Conclusions: In our study, we developed a formula that estimates the anticoagulant activity of rivaroxaban by obtaining INR values. Where anti-FXa assay is unavailable, our proposed formula may be considered as a screening test for rivaroxaban.

Drug levels and bleeding complications in atrial fibrillation patients treated with direct oral anticoagulants

Essentials Currently, DOACs are given at fixed doses and do not require laboratory monitoring. Direct oral anticoagulant-specific measurements were performed at trough and peak. Patients who developed bleeding events showed higher DOAC plasma levels at peak. This study suggests the need of a more accurate DOAC dose assessment.

BACKGROUND

Direct oral anticoagulants (DOACs) are administered at fixed dose. The aim of the study was to evaluate the relationship between DOAC C-trough or C-peak plasma levels and bleeding complications in patients with non-valvular atrial fibrillation (NVAF).

METHODS

Five hundred sixty five consecutive naive NVAF patients were enrolled. The DOAC measurements at C-trough and at C-peak (available in 411 patients) were performed at steady state, within the first month of treatment. Major bleeding (MB), clinically relevant non-major bleeding (CRNMB), and minor bleeding (MinB), occurring during 1 year of follow-up after blood sampling, were recorded. For each DOAC, interval of C-trough and C-peak levels was subdivided into four equal classes and results were attributed to these classes; the median values of results were also calculated.

RESULTS

Two hundred eight patients were on apixaban, 185 on dabigatran, and 172 on rivaroxaban. For 1-[qqqdeletezzz] year follow up for all patients, we observed: 19 MB (3.36%), 6 CRNMB (1.06%), and 47 MinB (8.31%). The prevalence of bleeding patients with anticoagulant levels in the upper classes of C-peak activity (II + III + IV) was higher than that in the lowest class. Normalized results of C-peak levels were higher in patients with bleeding than in those without bleeding.

CONCLUSIONS

Bleeding complications during DOAC treatment were more frequent among atrial fibrillation (AF) patients with higher C-peak anticoagulant levels. In addition to a previous study that showed an increased risk of thrombotic complications in the patients with low C-trough levels, this study seems to indicate that patients with NVAF on DOACs would need a more accurate definition of their optimal therapeutic window.

Management of major bleeding and outcomes in patients treated with direct oral anticoagulants: results from the START-Event registry

The management of major bleeding in patients treated with direct oral anticoagulants (DOACs) is still not well established. START-Events, a branch of the START registry (Survey on anTicoagulated pAtients RegisTer) (NCT02219984), aims to describe the actual management of bleeding or recurrent thrombotic events in routine clinical practice. We here present the results of the management of bleeding patients. The START-Event registry is a prospective, observational, multicenter, international study. Baseline characteristics (demographic, clinical, risk factors) of patients, laboratory data at admission and during follow-up, site of bleeding, therapeutic strategies, and outcomes at the time of hospital discharge and after 6 months were recorded on a web-based case report form. Between January 2015 and December 2016, 117 patients with major bleeding events were enrolled. Non-valvular atrial fibrillation (NVAF) was the indication for treatment in 84% (62% males); 53 patients had intracranial bleeding (13 fatal), 42 had gastrointestinal bleeding (1 fatal), and 22 had bleeding in other sites. Therapeutic interventions for the management of bleeding were performed in 71% of patients. Therapeutic strategies with/without surgery or invasive procedures included: fluid replacement or red blood cells transfusion, prothrombin complex concentrates (3 or 4 factors), antifibrinolytic drugs, and the administration of idarucizumab. Creatinine, blood cell count, and PT/aPTT were the most frequent tests requested, while specific DOAC measurements were performed in 23% of patients. Mortality during hospitalization was 11.9%, at 6-month follow-up 15.5%. Our data confirm a high heterogeneity in the management of bleeding complications in patients treated with DOACs.

Low drug levels and thrombotic complications in high-risk atrial fibrillation patients treated with direct oral anticoagulants

Essentials Direct oral anticoagulants (DOACs) do not require laboratory monitoring currently. DOAC specific measurements were performed at trough in patients with atrial fibrillation. Patients who developed thromboembolic events showed lower DOAC plasma levels. This study supports the concept of measuring DOAC levels at steady state.

SUMMARY

Background Direct oral anticoagulants (DOACs) are administered at fixed doses without the need for dose adjustment according to laboratory testing. High interindividual variability in drug blood levels has been shown with all DOACs. To evaluate a possible relationship between DOAC C-trough anticoagulant levels and thromboembolic events, 565 consecutive naive patients with atrial fibrillation (AF) were enrolled in this study performed within the START Laboratory Registry. Methods DOAC-specific measurements (diluted thrombin time or anti-activated factor II calibrated for dabigatran; anti-activated FX calibrated for rivaroxaban or apixaban) at C-trough were performed locally at steady state within 15-25 days after the start of treatment. For each DOAC, the interval of C-trough levels, from the limit of quantification to the highest value, was subdivided into four equal classes, and results were attributed to these classes; the median values of results were also calculated. Thromboembolic complications occurring during 1 year of follow-up were recorded. Results Thromboembolic events (1.8%) occurred in 10 patients who had baseline C-trough levels in the lowest class of drug levels. The incidence of thromboembolic events among patients with DOAC C-trough levels in the lowest level class was 2.4%, and that in the remaining groups was 0%. The patients with thrombotic complications also had a higher mean CHA2 DS2 -VASc score than that of the total patient population: 5.3 (95% confidence interval [CI] 4.3-6.3 versus 3.0 (95% CI 2.9-3.1). Conclusion In this study cohort, thrombotic complications occurred only in DOAC-treated AF patients who had very low C-trough levels, with a relatively high CHA2 DS2 -VASc score. Larger studies are warranted to confirm these preliminary observations.

The Use of Idarucizumab for Dabigatran Reversal in Clinical Practice: A Case Series

PURPOSE

To describe the use of idarucizumab (Praxbind, Boehringer Ingelheim) in routine clinical practice at a large urban academic medical center.

SUMMARY

Seven total doses of idarucizumab were administered to six unique patients from October 31, 2015, to October 31, 2016. The reversal agent was used in conjunction with local bleeding control measures, blood product transfusions, and acid-suppressive therapy. In 86% of cases, idarucizumab administration resulted in a successful cessation of bleeding by clinical assessment. Two patients expired due to coexisting conditions. Idarucizumab was administered to patients with normal baseline coagulation tests in 43% of cases. No adverse reactions related to idarucizumab were reported.

CONCLUSIONS

Idarucizumab administration resulted in successful resolution of bleeding by clinical assessment. The therapy for acute bleeding with use of dabigatran (Pradaxa, Boehringer Ingelheim) remains supportive care, in addition to idarucizumab in cases of severe or uncontrolled bleeding. Development of institution-specific protocols and better guidance for using baseline coagulation tests are needed.

Position Paper on laboratory testing for patients on direct oral anticoagulants. A Consensus Document from the SISET, FCSA, SIBioC and SIPMeL

Although direct oral anticoagulants (DOAC) do not require dose-adjustment on the basis of laboratory test results, the measurement of their anticoagulant effect is useful in special situations. This position paper issued by the Italian Scientific Societies that are mainly involved in the management of patients on DOAC is aimed at providing guidance to care-givers on which tests should be used and the situations in which testing is useful. The guidance is based on the data from the literature so far available and/or on consensus among experts.

Targeted Thromboelastographic (TEG) Blood Component and Pharmacologic Hemostatic Therapy in Traumatic and Acquired Coagulopathy

Trauma-induced coagulopathy (TIC) is a recently described condition which traditionally has been diagnosed by the common coagulation tests (CCTs) such as prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), platelet count, and fibrinogen levels. The varying sensitivity and specificity of these CCTs have led trauma coagulation researchers and clinicians to use Viscoelastic Tests (VET) such as Thromboelastography (TEG) to provide Targeted Thromboelastographic Hemostatic and Adjunctive Therapy (TTHAT) in a goal directed fashion to those trauma patients in need of hemostatic resuscitation. This review describes the utility of VETs, in particular, TEG, to provide TTHAT in trauma and acquired non-trauma-induced coagulopathy.

Clinical pearls: Laboratory assessments of direct oral anticoagulants (DOACS)

Direct oral anticoagulants (DOACS) are being used for stroke prevention in patients with atrial fibrillation as well as for prophylaxis and treatment of venous thromboembolism. Clinicians who treat, or may encounter, patients with DOAC exposure, should be aware of the limitations of coagulation testing in this setting, and seek counsel from their laboratory to understand the effects of DOACS on coagulation results. Generally, assays that employ clot based principles, or methods that require thrombin or Factor Xa activation or substrates may be affected by the presence of DOACS. The clinical laboratory should have an algorithmic testing plan for adequately assessing the presence of all DOACS and readily provide this information to clinicians. We describe Clinical Pearls for DOAC assessment using common and esoteric coagulation testing.

Reversal agents for use with direct and indirect anticoagulants

PURPOSE

The properties of three oral anticoagulant-specific reversal agents are reviewed, and guidance is presented to assist pharmacists in planning for the agents' introduction to the market.

SUMMARY

Idarucizumab, which received Food and Drug Administration approval in October 2015, is a humanized monoclonal antibody fragment that immediately neutralizes the anticoagulant effect of dabigatran, as evidenced by reduced unbound dabigatran concentrations and normalized coagulation tests. Preliminary Phase III trial results demonstrated a median maximum reversal of 100%, a median time to bleeding cessation of 11.4 hours, and normal intraoperative hemostasis in 92% of patients requiring anticoagulation reversal before an urgent procedure. Andexanet alfa is a factor Xa (FXa) decoy that binds to direct and indirect FXa inhibitors. In Phase III trials in healthy volunteers, andexanet alfa reduced anti-FXa activity by more than 90%, reduced the concentration of unbound direct FXa inhibitor, and inhibited thrombin generation. Ciraparantag is a reversal agent under development for reversal of anticoagulation with direct and indirect FXa inhibitors and certain factor IIa inhibitors; it exerts its effect through hydrogen bonding. Concerns for thromboembolic events directly related to administration of idarucizumab, andexanet alfa, or ciraparantag have not arisen. Pharmacists need to begin preparing for the introduction of these specific reversal agents through protocol development and provider education; in addition, pharmacy departments need to plan for procurement and storage. The specific reversal agents should be incorporated into antithrombotic stewardship or other clinical pharmacy programs for surveillance.

CONCLUSION

As agents that provide rapid reversal of direct oral anticoagulant activity become available, advance planning will help hospitals to optimize their use.

[Perioperative management of patients on NOACs]

Regarding thromboembolic events, non-vitamin K antagonists, so-called new oral anticoagulative agents (NOACs), have widely enlarged prophylaxis and therapy. In contrast to vitamin K antagonists they can be administered in a definite dose and do not need any regular control of coagulation parameters. Thus being simple in handling, these drugs have become enormously attractive for both patient and physician.In spite of all their advantages NOACs have to be considered carefully. They have a significant disadvantage: the plasma concentration is not detectable by a simple blood test, nor is there any antidote available. As a consequence the bleeding risk remains unknown.In this review we focus on two different settings in routine surgical work: the preoperative management of patients undergoing elective surgery differs significantly from that needed in urgent surgery.

"Threshold-crossing": A Useful Way to Establish the Counterfactual in Clinical Trials?

A central question in the assessment of benefit/harm of new treatments is: how does the average outcome on the new treatment (the factual) compare to the average outcome had patients received no treatment or a different treatment known to be effective (the counterfactual)? Randomized controlled trials (RCTs) are the standard for comparing the factual with the counterfactual. Recent developments necessitate and enable a new way of determining the counterfactual for some new medicines. For select situations, we propose a new framework for evidence generation, which we call "threshold-crossing." This framework leverages the wealth of information that is becoming available from completed RCTs and from real world data sources. Relying on formalized procedures, information gleaned from these data is used to estimate the counterfactual, enabling efficacy assessment of new drugs. We propose future (research) activities to enable "threshold-crossing" for carefully selected products and indications in which RCTs are not feasible.

Poor comparability of coagulation screening test with specific measurement in patients receiving direct oral anticoagulants: results from a multicenter/multiplatform study

Essentials Prothrombin and partial thromboplastin time (PT/PTT) measure direct oral anticoagulants (DOACs). PT, PTT and specific tests for DOACs were performed on patients treated for atrial fibrillation. Normal PT/PTT don't exclude DOAC activity and their prolongation doesn't confirm DOAC action. The use of PT or PTT to evaluate DOAC activity could cause dangerous misinterpretations.

SUMMARY

Background Prothrombin time (PT) and activated partial thromboplastin time (APTT) have been proposed to measure the effect of oral anti-activated factor X (FXa) or anti-activated FII drugs, respectively. Aims To evaluate the relationships and responsiveness of PT and APTT versus direct oral anticoagulant (DOAC) concentrations measured with specific coagulation tests performed with different platforms in four Italian anticoagulation clinics. Methods Six hundred and thirty-five patients with atrial fibrillation participated in the study: 240 were receiving dabigatran, 264 were receiving rivaroxaban, and 131 were receiving apixaban. Blood was taken at trough and peak within the first month (15-25 days) of treatment. PT, APTT, diluted thrombin time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban were determined. Results For dabigatran, the correlation between APTT and dTT ranged from r = 0.80 to r = 0.62. For rivaroxaban, the correlation between the anti-FXa assay and PT ranged from r = 0.91 to r = 0.73. For apixaban, the correlation between the anti-FXa assay and PT was lower than for the two other drugs (r = 0.81 to r = 0.54). Despite the above significant correlations, the responsiveness of PT or APTT was relatively poor. A discrepancy between global testing and DOAC plasma concentrations was shown in a considerable proportion of patients, depending on the platform and drug, with values ranging from 6% to 62%. Conclusions Overall, poor responsiveness of the screening tests to DOAC concentrations was observed. PT and APTT normal values cannot exclude DOAC anticoagulant activity, and PT or APTT prolongation is not always associated with DOAC anticoagulant effect as determined with specific tests.

Idarucizumab: A Review as a Reversal Agent for Dabigatran

Idarucizumab (Praxbind(®)), a humanized monoclonal antibody, is a specific reversal agent for the direct oral thrombin inhibitor dabigatran, available as its prodrug dabigatran etexilate (Pradaxa(®)). Idarucizumab is approved in several countries (including the USA, the EU, Canada and Australia) for use in adult patients on dabigatran when the reversal of its anticoagulant effects is required for emergency surgery/procedures or in the event of life-threatening or uncontrolled bleeding. In the ongoing pivotal RE-VERSE AD trial in these populations (n = 90), intravenous idarucizumab 5 g reversed dabigatran-induced prolongation of dilute thrombin time (dTT) and ecarin clotting time (ECT) within minutes. The median maximum percentage reversal was 100 % for both assays (primary endpoint). Idarucizumab normalized dTT and ECT in 88-98 % of patients who had elevated levels at baseline. After idarucizumab administration, bleeding stopped in 97 % of evaluable patients in the bleeding cohort within 24 h (median time to cessation of bleeding was 11.4 h), and the rate of normal intraoperative haemostasis was 92 % in the surgical cohort. Idarucizumab was generally well tolerated. In conclusion, idarucizumab is a unique and specific treatment option for the reversal of the anticoagulant effects of dabigatran in adult patients requiring emergency procedures or in the event of life-threatening or uncontrolled bleeding.

Measuring non-vitamin K antagonist oral anticoagulant levels: When is it appropriate and which methods should be used?

Background

Although the need for an emergency intervention may merit laboratory measurement of non-vitamin K antagonist oral anticoagulant (NOAC) concentration or anticoagulant activity, NOACs are not supposed to require routine monitoring due to their stable pharmacological profiles compared with warfarin.

Aims

To examine situations where NOAC measurement may be useful and to provide information about methodologies available to measure NOAC-related anticoagulation activity.

Summary of review

The routine coagulation tests, including prothrombin time, thrombin time, activated partial thromboplastin time, and international normalized ratio, have variable sensitivities to NOACs. Tests have been developed for use with specific NOACs, e.g. diluted thrombin time or chromogenic factor Xa assays. In emergency situations, such as severe bleeding, stroke, or a requirement for urgent surgery or procedures, there may be a need to assess anticoagulant activity to guide clinical decision making. In cases where neutralization of the anticoagulant effect is warranted, specific reversal agents are likely to become invaluable medical tools. Evidence to date suggests that dosing decisions for NOACs based on clinical features (e.g. age or renal function) can help optimize the benefit–risk balance without assessment of anticoagulant activity in non-emergency routine situations.

Conclusions

Regular monitoring of NOAC levels does not provide benefits and cannot be recommended at present. In some specific circumstances, e.g. severe bleeding, before urgent surgery, or before thrombolysis, measurement may be beneficial to assess whether a patient is actively anticoagulated. The availability of NOAC-specific reversal agents may change management practices in emergencies.

Reversal of Dabigatran with Idarucizumab

INTRODUCTION

The use of novel oral anticoagulants such as dabigatran has been increasing over the last five years. Indicated for use in the prevention of thromboembolic complications from non-valvular atrial fibrillation and for the treatment and prevention of venous thromboembolic disease, dabigatran is increasingly encountered clinically. Lack of an efficacious reversal agent has been a challenge for increased clinical 10 adoption, and for management of patients with bleeding complications while taking dabigatran, or those requiring urgent procedures while taking dabigatran. Idarucizumab, a monoclonal antibody fragment, has recently been approved for use to reverse anticoagulation with dabigatran in patients with serious bleeding.

AREAS COVERED

Herein we discuss the development and early clinical data evaluating the use of idarucizumab for dabigatran reversal. Expert commentary: Idarucizumab has been shown to be an efficacious reversal agent for patients receiving dabigatran. The drug provides a novel and clinically useful agent for patients with significant bleeding while receiving dabigatran, or those needing urgent invasive procedures.

Prothrombin Time Tests for the Monitoring of Direct Oral Anticoagulants and Their Evaluation as Indicators of the Reversal Effect

INTRODUCTION

The prompt assessment and the reversal of direct oral anticoagulants (DOACs) are urgent matters in the emergency care setting. Thus, we planned to elucidate the adequate prothrombin time (PT) test for the evaluation of the anticoagulant effects of various DOACs.

METHODS

The anticoagulant effects of rivaroxaban, apixaban, and edoxaban were measured with 3 PT tests (Triniclot PT Excel S, Neoplastin R, and Thromborel S). Human plasma was spiked with each DOAC at a range of 0 to 1000 ng/mL, and the PT was measured using each PT test. In another series, the reversal effect of either 4-factor prothrombin complex concentrate (PCC) or activated PCC (aPCC) was evaluated with each PT test.

RESULTS

All PT reagents correlated with the concentrations of each DOAC, however, the reactivity was considerably different between the DOACs and the PT tests. A prolonged PT with DOACs was reversed both by PCC and aPCC in a dose-dependent manner; however, Triniclot PT Excel S showed reprolongation of the PT with a higher dose of PCC.

CONCLUSION

The proper choice of PT test is necessary for the assessments of the anticoagulant activity of DOACs. It is also important to understand the different characteristics of each PT test for the assessment of the reversal effects of PCC.

Comparison of prothrombin time tests used in the monitoring of edoxaban and their evaluation as indicators of the reversal effect

Clinical demand for the prompt assessment of the activity of direct-acting factor Xa inhibitors in the emergency care setting is increasing. In the present study, we examined whether prothrombin time (PT) tests can serve as a clinically useful indicator of anti-factor Xa activity. In the first series, the in vitro effect of edoxaban on PT was evaluated by spiking human plasma with edoxaban and measuring PT using three different commercial PT tests. In the second series, the reversal effect of prothrombin complex concentrates (PCC) and activated PCC (aPCC) in edoxaban-spiked plasma was evaluated. In the third series, PT of plasma samples from patients administered either 15 or 30 mg/day of edoxaban was assessed, and the results were compared with edoxaban concentrations determined by a calibrated anti-factor Xa activity assay. The spike test revealed that all PT reagents positively correlated with edoxaban. The sensitivity to edoxaban varied among the three reagents and Triniclot(®) Excel S showed the best performance. Prolonged PT by edoxaban was reversed by PCC and aPCC in a dose-dependent manner; however, complete reversal was not achieved. Positive correlation between anti-factor Xa activity and PT was shown in the clinical samples at the edoxaban range from 0 to >300 ng/mL.

New Insights into the Pros and Cons of the Clinical Use of Vitamin K Antagonists (VKAs) Versus Direct Oral Anticoagulants (DOACs)

Vitamin K-antagonists (VKA) are the most widely used anticoagulant drugs to treat patients at risk of arterial and venous thrombosis for the past 50 years. Due to unfavorable pharmacokinetics VKA have a small therapeutic window, require frequent monitoring, and are susceptible to drug and nutritional interactions. Additionally, the effect of VKA is not limited to coagulation, but affects all vitamin K-dependent proteins. As a consequence, VKA have detrimental side effects by enhancing medial and intimal calcification. These limitations stimulated the development of alternative anticoagulant drugs, resulting in direct oral anticoagulant (DOAC) drugs, which specifically target coagulation factor Xa and thrombin. DOACs also display non-hemostatic vascular effects via protease-activated receptors (PARs). As atherosclerosis is characterized by a hypercoagulable state indicating the involvement of activated coagulation factors in the genesis of atherosclerosis, anticoagulation could have beneficial effects on atherosclerosis. Additionally, accumulating evidence demonstrates vascular benefit from high vitamin K intake. This review gives an update on oral anticoagulant treatment on the vasculature with a special focus on calcification and vitamin K interaction.

Novel antidotes for target specific oral anticoagulants

Target specific oral anticoagulants (dabigatran, rivaroxaban, apixaban, and edoxaban) are changing the landscape of anticoagulation. The major drawback is the absence of an effective antidote for severe bleedings and/or prior to procedures. Currently there are a few promising antidotes undergoing clinical trials. This review summarized the latest development in idarucizumab, andexanet alpha and PER977.