Management of bleeding in patients treated with direct oral anticoagulants

Mortality Rate in Upper Gastrointestinal Bleeding Associated with Anti-Thrombotic Therapy Before and During Covid-19 Pandemic

INTRODUCTION

During the last few years, a progressive higher proportion of patients have had upper gastrointestinal bleeding (UGIB) related to antithrombotic therapy. The introduction of direct oral anticoagulant (DOAC) and COVID-19 pandemic may change the incidence, mortality, and follow-up, especially in patients at high risk of bleeding.

PATIENTS AND METHODS

We studied the use of anti-thrombotic therapy (AT) in patients with upper gastrointestinal bleeding for 5 years (January 2017-December 2021) including Covid-19 pandemic period (March 2020-December 2021). We analyzed mortality rate, rebleeding rate and need for transfusion in patients with AT therapy compared with those without AT therapy and risk factors for mortality, and also the incidence of gastrointestinal bleeding in patients admitted for COVID-19 infection.

RESULTS

A total of 824 patients were admitted during Covid-19 pandemic period and 1631 before pandemic period; a total of 426 cases of bleeding were recorded in patients taking antithrombotic therapy and the frequency of antithrombotic therapy in patients with UGIB was higher in pandemic period (24.39% versus 13.8%). Unadjusted mortality was 12.21%, similar with patients with no antithrombotic treatment but age-adjusted mortality was 9.62% (28% lower). The rate of endoscopy was similar but fewer therapeutic procedures were required. Mean Hb level was 10% lower, and more than 60% of patients required blood transfusion.

CONCLUSION

Mortality was similar compared with patients with no antithrombotic therapy, fewer therapeutic endoscopies were performed and similar rebleeding rate and emergency surgery were noted. Hb level was 10% lower and a higher proportion of patients required blood transfusions. Mortality was higher in DOAC treatment group compared with VKA patients but with no statistical significance. The rate of upper gastrointestinal bleeding in Covid-19 positive hospitalized cases was 0.58%. The mortality risk in multivariate analysis was associated with GB score, with no endoscopy performed, with obscure and variceal bleeding and with LMWH versus VKA therapy.

SHR2285, the first selectively oral FXIa inhibitor in China: Safety, tolerability, pharmacokinetics and pharmacodynamics combined with aspirin, clopidogrel or ticagrelor

Purpose: To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of SHR2285, the first oral coagulation factor XIa (FXIa) inhibitor developed in China in combination with aspirin, clopidogrel or ticagrelor in healthy subjects. Methods: This study was a single-center, randomized, double-blind, placebo-controlled (only SHR2285) design (NCT04945616). A total of 52 healthy subjects, 29 male and 23 female, were completed in this study. The subjects were divided into three groups: A, B and C, 16 subjects in group A [aspirin + clopidogrel + placebo or SHR2285 200 mg bid (1:3, 4 received placebo and 12 received SHR2285)] 16 subjects in group B [aspirin + clopidogrel + placebo or SHR2285 300 mg bid (1:3, 3 received placebo and 13 received SHR2285)] and 20 subjects in group C (aspirin + ticagrelor + placebo or SHR2285 300 mg bid (2:3, 8 received placebo and 12 received SHR2285)), respectively. All groups were administered orally for six consecutive days. Safety, tolerability, pharmacokinetics and pharmacodynamics parameters were assessed. Results: 1) SHR2285 was well tolerated, and all adverse events were mild. There was no evidence of an increased risk of bleeding. 2) After 6 days of twice-daily administration, SHR2285 could reach a steady state. The mean half-life of SHR2285 in group A, group B and group C was 13.9 h, 14.5 h and 13.8 h, respectively. 3) SHR2285 markedly inhibited FXI activity and prolonged activated partial thromboplastin time (APTT). In group A, group B and group C, the mean maximum inhibition rate of FXI activity was 84.8%, 89.3% and 92.2% and the mean maximum prolongation of APTT was 2.08-fold, 2.36-fold and 2.26-fold, respectively. Conclusion: These data suggest that SHR2285, a potential oral FXIa inhibitor, is expected to become a novel, safe and effective anticoagulant when combined with aspirin, clopidogrel or ticagrelor.

Factor XI Inhibition for the Prevention of Venous Thromboembolism: An Update on Current Evidence and Future perspectives

During the past decade, emergence of direct oral anticoagulants (DOACs) has drastically improved the prevention of thrombosis. However, several unmet needs prevail in the field of thrombosis prevention, even in the DOACs’ era. The use of DOACs is still constrained and the drugs cannot be administered in every clinical scenario, such as an increased anticoagulant-associated bleeding risk, particularly in some specific populations (cancer – notably those with gastrointestinal or genitourinary cancer – and frail patients), the impossibility to be used in certain patients (eg, end-stage kidney failure during hemodialysis, pregnancy and breastfeeding), and their lack of efficacy in certain clinical scenarios (eg, mechanical heart valves, triple-positive antiphospholipid syndrome). Efforts to find a factor that upon antagonization prevents thrombosis but spares haemostasis have resulted in the identification of coagulation factor XI (FXI) as a therapeutic target. After briefly recapitulating the role of factor XI in the balance of haemostasis, we propose a narrative review of the key data published to date with compounds targeting factor XI to prevent thrombosis as well as the main ongoing clinical studies, opening up prospects for improving the care of patients requiring thrombosis prevention.

Therapeutic strategies for thrombosis: new targets and approaches

Antiplatelet agents and anticoagulants are a mainstay for the prevention and treatment of thrombosis. However, despite advances in antithrombotic therapy, a fundamental challenge is the side effect of bleeding. Improved understanding of the mechanisms of haemostasis and thrombosis has revealed new targets for attenuating thrombosis with the potential for less bleeding, including glycoprotein VI on platelets and factor XIa of the coagulation system. The efficacy and safety of new agents are currently being evaluated in phase III trials. This Review provides an overview of haemostasis and thrombosis, details the current landscape of antithrombotic agents, addresses challenges with preventing thromboembolic events in patients at high risk and describes the emerging therapeutic strategies that may break the inexorable link between antithrombotic therapy and bleeding risk.

Reversal agents for direct oral anticoagulants: considerations for hospital physicians and intensivists

Direct oral anticoagulants (DOACs) include dabigatran etexilate, a direct thrombin inhibitor, and specific inhibitors of activated coagulation factor X (FXa; e.g. apixaban, betrixaban, edoxaban, rivaroxaban). DOACs are associated with lower rates of major and fatal bleeding events compared with warfarin. Clinicians may need to achieve rapid reversal of anticoagulation effects of the DOACs in an emergency setting. Idarucizumab and andexanet alfa, which reverse the anticoagulant effects of dabigatran and FXa inhibitors, respectively, are DOAC reversal agents available in the US. Other reversal agents (e.g. ciraparantag for heparins, DOACs) are in development. Alternative nonspecific agents (e.g. fresh frozen plasma, prothrombin complex concentrate) are available. Nonspecific prohemostatic agents can counteract the anticoagulant action of DOACs in emergency situations, when specific reversal agents are unavailable. However, specific reversal agents are efficacious and safe and should be preferred when available. In this review, we discuss practical issues in the initiation of DOAC therapy, situations where reversal may be needed, coagulation assays, reversal agents, and post-reversal complications in the context of published evidence and guidelines.

Spontaneous Spinal Epidural Hematoma in a Patient on Rivaroxaban: Case Report and Literature Review

BACKGROUND

Spinal hematomas (SHs) are rare yet potentially debilitating causes of acute back pain. Although spontaneous SHs have been described in the setting of anticoagulation with warfarin or enoxaparin, few cases of spontaneous SH on direct oral anticoagulants (DOACs) have been reported.

CASE REPORT

We report a case of spontaneous spinal epidural hematoma in a patient on rivaroxaban. A 72-year-old man on rivaroxaban and aspirin presented with a 4-day history of nontraumatic back pain. In the emergency department he developed lower-extremity weakness and numbness, followed by urinary incontinence. Magnetic resonance imaging revealed spinal epidural hematoma at T11-L2. The patient underwent emergent decompression and hematoma evacuation and was discharged home 8 days later with complete resolution of symptoms. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Early recognition and surgical intervention for SHs with neurologic compromise is key to favorable outcome. Optimal timing of surgery in patients on DOACs requires an assessment of the risk of intraoperative or postoperative bleeding, an assessment of the patient's symptom progression, as well as an understanding of the pharmacokinetics of the DOAC used and possible reversal options available. We also review all published cases of spontaneous SHs in patients on DOACs and report on their management and outcomes.

Four-factor prothrombin complex concentrate improves thrombin generation and prothrombin time in patients with bleeding complications related to rivaroxaban: a single-center pilot trial

Background

Direct oral anticoagulants (DOACs) pose a great challenge for physicians in life-threatening bleeding events. The aim of this study was to test the efficacy of reversing the DOAC rivaroxaban using four-factor PCC (prothrombin complex concentrate), a non-specific reversing agent.

Methods

Patients with life-threatening bleeding events during rivaroxaban treatment were included and administered 25 U kg⁻¹ of PCC. Blood samples were collected immediately prior to as well as after PCC treatment at predefined time intervals. The primary endpoint was defined as the difference in thrombin generation (TG) parameters ETP (endogenous thrombin potential) and C_max (peak thrombin generation) prior to and ten minutes subsequent to PCC treatment.

Results

Thirteen patients, of whom the majority suffered from intra-cranial haemorrhage (ICH) or subdural haemorrhage (SDH), were included and administered PCC. The results show that the ETP (TG) significantly (p = 0.001) improved by 68% and C_max (TG) by 54% (p = 0.001) during PCC treatment. In addition, the Quick value (prothrombin time: Quick^PT) significantly improved by 28% and the activated partial thromboplastin time (aPTT) was decreased by 7% ten minutes after PCC administration. C_max was reduced at baseline, but not ETP, aPTT or Quick^PT. Lag time until initiation (TG, t_lag), thromboelastometry clotting time (CT_EXTEM) and time to peak (TG, t_max) correlated best with measured rivaroxaban levels and were out of normal ranges at baseline, but did not improve after PCC administration. In 77% of the patients bleeding (ICH/SDH-progression) ceased following PCC administration. During the study three participants passed away due to other complications not related to PCC treatment. The possibility of thrombosis formation was also evaluated seven days after administering PCC and no thromboses were found.

Conclusions

This study shows that use of PCC improved ETP, C_max, Quick^PT and aPTT. However, of these parameters, only C_max was reduced at the defined baseline. It can be concluded that CT_EXTEM, t_lag and t_max correlated best with the measured rivaroxaban levels. The study drug was found to be safe. Nonetheless, additional studies specifically targeting assessment of clinical endpoints should be performed to further confirm these findings.

Clinical trial registration

EudraCT trial No. 2013–004484-31.

Electronic supplementary material

The online version of this article (10.1186/s12959-017-0158-9) contains supplementary material, which is available to authorized users.

The inflammatory reflex and neural tourniquet: harnessing the healing power of the vagus nerve

The CNS helps protect against tissue injury. The most important priorities include limiting blood loss and systemic inflammation. We elucidated two endogenous neural pathways that rapidly and specifically improve hemostasis and decrease inflammation through vagus nerve signaling. Activation of the neural tourniquet or inflammatory reflex via electrical vagus nerve stimulation (VNS) significantly improves outcomes in preclinical disease models. Currently, VNS is clinically approved for the treatment of medically refractory epilepsy and depression. The growing field of bioelectronic medicine will help physicians harness the Neural Tourniquet™ and inflammatory reflex for clinical use as well. Considering the substantial harm caused by uncontrolled bleeding and inflammation, electrical VNS may dramatically improve the care of millions of patients.

Anticoagulant options in atrial fibrillation: When new treatments become standard practice

Direct oral anticoagulants (DOACs) have expanded options for treating patients with atrial fibrillation (AF). However, DOACs are not warfarin substitutes, and NPs need to be aware of the difference. DOACs are first-line agents when treating AF, yet warfarin has not been replaced. Individualized patient characteristics drive current guidelines.

An update on the bleeding risks associated with DOACs

The direct oral anticoagulants (DOACs), also referred to as novel (or non-vitamin K antagonist) oral anticoagulants (NOACs), represent a major development in anticoagulation therapy due to their rapid onset of action, predictable dose-response with fixed doses and limited interactions with food and drugs.^1,2 However, these agents have been in widespread clinical use for less than a decade and, compared with extensive experience with warfarin, there is uncertainty relating to optimal laboratory monitoring of anticoagulation, perioperative management and treatment of bleeding.3 In addition, there is currently only one drug licensed in the UK for rapid reversal of the anticoagulant effect of a DOAC. Here, we review DOAC-related bleeding and the role of drugs to reverse the anticoagulant action of DOACs.

Decision Algorithms for Direct Oral Anticoagulant Use in Patients With Nonvalvular Atrial Fibrillation: A Practical Guide for Neurologists

Direct oral anticoagulants (DOACs) are valid alternative options to vitamin K antagonists due to their limited interactions with drugs or food and the fact that they do not require regular coagulation monitoring. To this regard, recent practice guidelines recommend that DOACs should be considered as first-line anticoagulant therapy for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). This review (1) outlines current international guidelines for the management of DOACs to prevent stroke in patients with NVAF, (2) outlines indications for elderly patients as well as specific settings including acute coronary syndromes and intracranial hemorrhage, and (3) offers a practical guide for the use of DOACs in neurological settings.

The reversal effect of prothrombin complex concentrate (PCC), activated PCC and recombinant activated factor VII in apixaban-treated patients in vitro

BACKGROUND

The number of patients under treatment with FXa inhibitors is increasing, but there is no concensus on how to reverse their anticoagulant effect in case of a life-threatening bleeding. A specific antidote is not yet commercially available. Prothrombin complex concentrate (PCC), activated PCC (aPCC) and recombinant factor VIIa (rFVIIa) are suggested available reversal agents.

OBJECTIVES

To find the most effective reversal agent to apixaban and to determine the optimal dose.

PATIENTS/METHODS

PCC, aPCC, and rFVIIa at concentrations imitating 80%, 100%, and 125% of suggested therapeutic doses were added to blood drawn from apixaban-treated patients (n=30). aPCC was also tested in a 50% dose. Samples from healthy subjects (n=40) were used as controls. Thromboelastometry in whole blood (WB) and thrombin generation in platelet-poor plasma (PPP) were measured to assess the reversal effect.

RESULTS

aPCC shortened clotting time (CT) in WB, and increased the peak thrombin concentration and velocity index in PPP to a greater extent than PCC and rFVIIa. No significant differences were seen between rFVIIa and aPCC on thrombin generation lag time, or between PCC and aPCC on endogenous thrombin potential (ETP). The 50% dose of aPCC had a slightly inferior effect, but was comparable to the other reversal agents.

CONCLUSIONS

In this in vitro study the 80% dose of aPCC (40 IU/kg) reversed the anticoagulant effect of apixaban more effectively than the corresponding dose of rFVIIa and PCC both in WB (CT) and PPP (peak, ETP).

Severe trauma in the geriatric population

Geriatric trauma constitutes an increasingly recognized problem. Aging results in a progressive decline in cellular function which leads to a loose of their capacity to respond to injury. Some medications commonly used in this population can mask or blunt the response to injury. Falls constitute the most common cause of trauma and the leading cause of trauma-related deaths in this population. Falls are complicated by the widespread use of antiplatelets and anticoagulants, especially in patients with brain injury. Under-triage is common in this population. Evaluation of frailty could be helpful to solve this issue. Appropriate triaging and early aggressive management with correction of coagulopathy can improve outcome. Limitation of care and palliative measures must be considered in cases with a clear likelihood of poor prognosis.

Real-life experience with the specific reversal agent idarucizumab for the management of emergency situations in dabigatran-treated patients: a series of 11 cases

Non-vitamin K antagonist oral anticoagulants (NOACs) have a favorable benefit-risk profile compared with vitamin K antagonists. However, the lack of specific reversal agents has made the management of some patients receiving long-term treatment with NOACs problematic in emergency situations such as major bleeding events or urgent procedures. Idarucizumab, a fully humanized Fab antibody fragment that binds specifically and with high affinity to dabigatran, was recently approved for use in adult patients treated with dabigatran when rapid reversal of its anticoagulant effect is required. Clinical experience with idarucizumab is currently limited. We report 11 real-life clinical cases in which idarucizumab was used after multidisciplinary consultation in a variety of emergency situations including severe postoperative bleeding, emergency high-bleeding-risk surgery (hip/spine surgery and neurosurgery), invasive diagnostic testing (lumbar puncture), intracranial bleeding (pre-pontine subarachnoid hemorrhage and lobar intracerebral hemorrhage) and thrombolysis with recombinant tissue plasminogen activator for acute ischemic stroke. This case series illustrates the role of idarucizumab in improving patient safety in rare emergency situations requiring rapid reversal of the anticoagulant effect of dabigatran, while highlighting the importance of information and education about the availability and appropriate use of this recently approved specific reversal agent.

Rational Design of Protein C Activators

In addition to its procoagulant and proinflammatory functions mediated by cleavage of fibrinogen and PAR1, the trypsin-like protease thrombin activates the anticoagulant protein C in a reaction that requires the cofactor thrombomodulin and the endothelial protein C receptor. Once in the circulation, activated protein C functions as an anticoagulant, anti-inflammatory and regenerative factor. Hence, availability of a protein C activator would afford a therapeutic for patients suffering from thrombotic disorders and a diagnostic tool for monitoring the level of protein C in plasma. Here, we present a fusion protein where thrombin and the EGF456 domain of thrombomodulin are connected through a peptide linker. The fusion protein recapitulates the functional and structural properties of the thrombin-thrombomodulin complex, prolongs the clotting time by generating pharmacological quantities of activated protein C and effectively diagnoses protein C deficiency in human plasma. Notably, these functions do not require exogenous thrombomodulin, unlike other anticoagulant thrombin derivatives engineered to date. These features make the fusion protein an innovative step toward the development of protein C activators of clinical and diagnostic relevance.