The reversal effect of prothrombin complex concentrate (PCC), activated PCC and recombinant activated factor VII against anticoagulation of Xa inhibitor

Co-administration of Four-Factor Prothrombin Complex Concentrate With Andexanet alfa for Reversal of Nontraumatic Intracranial Hemorrhage

Objective: Andexanet alfa is approved for the reversal of life-threatening or uncontrolled bleeding due to factor-Xa inhibitors. Data are limited on outcomes for patients who receive both andexanet alfa and 4-factor prothrombin complex concentrate (4F-PCC). The aim of this case series is to evaluate the safety and efficacy outcomes in patients receiving the two agents in combination. Methods: Electronic medical records of patients who received both 4F-PCC and andexanet alfa for nontraumatic intracranial hemorrhage from January 2019 to March 2022 were retrospectively reviewed. Hemostatic efficacy and complications related to concurrent use of 4F-PCC with andexanet alfa were documented. Results: Nine patients received 4F-PCC and andexanet alfa for reversal of factor Xa inhibitor-associated intracranial bleeding, eight of whom required reversal of apixaban. Of these nine patients, five patients died within 28 days for a 56% incidence of mortality. The average time from 4F-PCC administration to andexanet alfa administration was 3 hours and 9 minutes. Most doses of andexanet alfa were given for concern for bleed expansion after 4F-PCC administration. Hemostatic efficacy based on stability of repeat computed tomography scans post-administration of both agents was found in six patients (66.67%), with a 55.56% n incidence of thromboembolism, including two pulmonary embolisms, two deep vein thromboses, and one renal artery thrombosis. Conclusion: Risks and benefits should be weighed to determine if there is benefit to adding andexanet alfa to 4F-PCC in patients with incomplete hemostasis and life-threatening hemorrhage. The combination of andexanet alfa and 4F-PCC may increase the risk of thrombotic complications without improving mortality.

Clinical guideline on reversal of direct oral anticoagulants in patients with life threatening bleeding

BACKGROUND

Anticoagulation is essential for the treatment and prevention of thromboembolic events. Current guidelines recommend direct oral anticoagulants (DOACs) over vitamin K antagonists in DOAC-eligible patients. The major complication of anticoagulation is serious or life-threatening haemorrhage, which may necessitate prompt haemostatic intervention. Reversal of DOACs may also be required for patients in need of urgent invasive procedures. This guideline from the European Society of Anaesthesiology and Intensive Care (ESAIC) aims to provide evidence-based recommendations and suggestions on how to manage patients on DOACs undergoing urgent or emergency procedures including the treatment of DOAC-induced bleeding.

DESIGN

A systematic literature search was performed, examining four drug comparators (dabigatran, rivaroxaban, apixaban, edoxaban) and clinical scenarios ranging from planned to emergency surgery with the outcomes of mortality, haematoma growth and thromboembolic complications. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to assess the methodological quality of the included studies. Consensus on the wording of the recommendations was achieved by a Delphi process.

RESULTS

So far, no results from prospective randomised trials comparing two active comparators (e.g. a direct reversal agent and an unspecific haemostatic agent such as prothrombin complex concentrate: PCC) have been published yet and the majority of publications were uncontrolled and observational studies. Thus, the certainty of evidence was assessed to be either low or very low (GRADE C). Thirty-five recommendations and clinical practice statements were developed. During the Delphi process, strong consensus (>90% agreement) was achieved in 97.1% of recommendations and consensus (75 to 90% agreement) in 2.9%.

DISCUSSION

DOAC-specific coagulation monitoring may help in patients at risk for elevated DOAC levels, whereas global coagulation tests are not recommended to exclude clinically relevant DOAC levels. In urgent clinical situations, haemostatic treatment using either the direct reversal or nonspecific haemostatic agents should be started without waiting for DOAC level monitoring. DOAC levels above 50 ng ml-1 may be considered clinically relevant necessitating haemostatic treatment before urgent or emergency procedures. Before cardiac surgery under activated factor Xa (FXa) inhibitors, the use of andexanet alfa is not recommended because of inhibition of unfractionated heparin, which is needed for extracorporeal circulation. In the situation of DOAC overdose without bleeding, no haemostatic intervention is suggested, instead measures to eliminate the DOACs should be taken. Due to the lack of published results from comparative prospective, randomised studies, the superiority of reversal treatment strategy vs. a nonspecific haemostatic treatment is unclear for most urgent and emergency procedures and bleeding. Due to the paucity of clinical data, no recommendations for the use of recombinant activated factor VII as a nonspecific haemostatic agent can be given.

CONCLUSION

In the clinical scenarios of DOAC intake before urgent procedures and DOAC-induced bleeding, practitioners should evaluate the risk of bleeding of the procedure and the severity of the DOAC-induced bleeding before initiating treatment. Optimal reversal strategy remains to be determined in future trials for most clinical settings.

DOAC-associated bleeding, hemostatic strategies, and thrombin generation assays - a review of the literature

Direct oral anticoagulants (DOACs) account for most oral anticoagulant use. DOAC-associated bleeding events are commonly encountered in clinical practice and are associated with substantial morbidity and mortality. Both specific reversal agents and nonspecific hemostatic therapies, such as prothrombin complex concentrates, are used in the management of DOAC-associated bleeding. Measuring hemostatic efficacy and demonstrating a clinical impact from these therapies among studies of bleeding patients is challenging. Thrombin generation assays provide information on the total hemostatic potential of plasma, and have emerged as a promising modality to both measure the impact of DOACs on coagulation and to evaluate the effects of hemostatic therapies among patients with DOAC-associated bleeding. The mechanisms by which nonspecific hemostatic agents impact coagulation and thrombin generation in the context of DOAC therapy are unclear. As a result, we undertook a review of the literature using a systematic search strategy with the goal of summarizing the effects of DOACs on thrombin generation and the effects of both specific reversal agents and nonspecific hemostatic therapies on DOAC-altered thrombin generation parameters. We sought to identify clinical studies focusing on whether altered thrombin generation is associated with clinical bleeding and whether correction of altered thrombin generation parameters predicts improvements in clinical hemostasis. Lastly, we sought to outline future directions for the application of thrombin generation assays toward anticoagulation therapies and the question of anticoagulation reversal.

A Historical Perspective on the Reversal of Anticoagulants

There has been a landmark shift in the last several decades in the management and prevention of thromboembolic events. From the discovery of parenteral and oral agents requiring frequent monitoring as early as 1914, to the development of direct oral anticoagulants (DOACs) that do not require monitoring or dose adjustment in the late 20th century, great advances have been achieved. Despite the advent of these newer agents, bleeding continues to be a key complication, affecting 2 to 4% of DOAC-treated patients per year. Bleeding is associated with substantial morbidity and mortality. Although specific reversal agents for DOACs have lagged the release of these agents, idarucizumab and andexanet alfa are now available as antagonists. However, the efficacy of these reversal agents is uncertain, and complications, including thrombosis, have not been adequately explored. As such, guidelines continue to advise the use of nonspecific prohemostatic agents for patients requiring reversal of the anticoagulant effect of these drugs. As the indications for DOACs and the overall prevalence of their use expand, there is an unmet need for further studies to determine the efficacy of specific compared with nonspecific pro-hemostatic reversal agents. In this review, we will discuss the evidence behind specific and nonspecific reversal agents for both parenteral and oral anticoagulants.

Cerebral Hemorrhage: Pathophysiology, Treatment, and Future Directions

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high morbidity and mortality. This review article focuses on the epidemiology, cause, mechanisms of injury, current treatment strategies, and future research directions of ICH. Incidence of hemorrhagic stroke has increased worldwide over the past 40 years, with shifts in the cause over time as hypertension management has improved and anticoagulant use has increased. Preclinical and clinical trials have elucidated the underlying ICH cause and mechanisms of injury from ICH including the complex interaction between edema, inflammation, iron-induced injury, and oxidative stress. Several trials have investigated optimal medical and surgical management of ICH without clear improvement in survival and functional outcomes. Ongoing research into novel approaches for ICH management provide hope for reducing the devastating effect of this disease in the future. Areas of promise in ICH therapy include prognostic biomarkers and primary prevention based on disease pathobiology, ultra-early hemostatic therapy, minimally invasive surgery, and perihematomal protection against inflammatory brain injury.

Use of Prothrombin Complex Concentrate in Oral Anticoagulant-Associated Major Bleeding

Severe bleeding remains the most significant adverse effect associated with both warfarin and the direct oral anticoagulant agents. Due to the life-threatening nature of these bleeds, knowledge and understanding of agents that are able to rapidly overcome the anticoagulation effects of these medications is paramount to their use. Worldwide, the most commonly used agent for this indication is prothrombin complex concentrate (PCC). This review summarizes the evidence on the use of PCC in this population and provides practical information regarding patient-specific administration considerations.

Four-factor prothrombin complex concentrate plus andexanet alfa for reversal of factor Xa inhibitor-associated bleeding: Case series

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

To manage factor Xa (FXa) inhibitor-associated bleeding, andexanet alfa or 4-factor prothrombin concentrate (4F-PCC) has been used to restore hemostasis. However, literature on the outcomes for patients who received both andexanet alfa and 4F-PCC is limited.

SUMMARY

We report a case series of 5 patients who received andexanet alfa plus 4F-PCC for reversal of FXa inhibitor-associated bleeding. Patients were included in this case series if they received both andexanet alfa and 4F-PCC for reversal of FXa inhibitor-associated bleeding. They were followed to either discharge or death, and in-hospital complications related to concurrent use of andexanet alfa and 4F-PCC were documented. We report an incidence of thromboembolism of 40% (2 of 5 cases) and an in-hospital mortality rate of 60% (3 of 5 cases). Taking these cases together with those in the existing literature, we found a total of 23 reported cases of safety outcomes with andexanet alfa plus 4F-PCC. The overall incidence of thromboembolism was 35% (8 of 23 cases).

CONCLUSION

This case series adds to the limited literature describing the outcomes for patients receiving andexanet alfa plus 4F-PCC. We encourage other institutions to report safety data on administering both agents.

"In Less than No Time": Feasibility of Rotational Thromboelastometry to Detect Anticoagulant Drugs Activity and to Guide Reversal Therapy

Anticoagulant drugs (i.e., unfractionated heparin, low-molecular-weight heparins, vitamin K antagonists, and direct oral anticoagulants) are widely employed in preventing and treating venous thromboembolism (VTE), in preventing arterial thromboembolism in nonvalvular atrial fibrillation (NVAF), and in treating acute coronary diseases early. In certain situations, such as bleeding, urgent invasive procedures, and surgical settings, the evaluation of anticoagulant levels and the monitoring of reversal therapy appear essential. Standard coagulation tests (i.e., activated partial thromboplastin time (aPTT) and prothrombin time (PT)) can be normal, and the turnaround time can be long. While the role of viscoelastic hemostatic assays (VHAs), such as rotational thromboelastometry (ROTEM), has successfully increased over the years in the management of bleeding and thrombotic complications, its usefulness in detecting anticoagulants and their reversal still appears unclear.

Bleeding phenotype of patients with moderate haemophilia A and B assessed by thromboelastometry and thrombin generation

INTRODUCTION

Predicting the bleeding phenotype is crucial for the management of patients with moderate haemophilia. Global coagulation assays evaluate haemostasis more comprehensively than conventional methods.

AIM

To explore global coagulation assays and the bleeding phenotype of patients with moderate haemophilia A (MHA) and B (MHB).

METHODS

The MoHem study is a cross-sectional, multicentre study covering Nordic patients with MHA and MHB. Thromboelastometry in whole blood and thrombin generation (TG) in platelet-poor plasma (1, 2.5 and 5 pM tissue factor (TF)) were compared with joint health (Haemophilia Joint Health Score (HJHS)) and treatment modality.

RESULTS

We report on 61 patients from Oslo and Helsinki: 24 MHA and 37 MHB. By TG (2.5 pM TF), patients who had been without replacement therapy during the previous 12 months depicted higher endogenous thrombin potential (P = .03). In contrast, those who had low ETP (< median) captured higher HJHS (P = .02). Patients who had undergone orthopaedic surgery generated least thrombin (P = .02). By thromboelastometry, those without the need of factor consumption had short clotting times, and quick times to maximum velocity (< median values) (P = .03). Factor VIII/factor IX activity (FVIII/FIX:C) did not align with the bleeding phenotype, but FIX:C ≤ 3 IU/dL was associated with lower peak thrombin (P = .03).

CONCLUSION

TG differentiated patients with moderate haemophilia according to HJHS, annual factor consumption, and whether orthopaedic surgery had been performed. Thromboelastometry differentiated according to factor consumption only. Global coagulation assays may assist predicting the bleeding phenotype in moderate haemophilia.

Investigation of the Optimal Dose aPCC in Reversing the Effect of Factor Xa Inhibitors-An In Vitro Study

Factor (F) Xa inhibitors are safe and effective alternatives to warfarin. There are concerns about the lack of a reversal strategy in case of serious bleeds or need for emergency surgery in situations when the antidote andexanet alfa is not available. Factor concentrates are widely used, but there are few clinical studies regarding the reversal effect of activated prothrombin complex concentrate (aPCC). Because of the feared thrombogenicity, administration of the lowest effective dose would be desirable. To determine the lowest concentration of aPCC sufficient to reverse the effect of rivaroxaban and apixaban. Blood from 18 healthy volunteers were supplemented with apixaban or rivaroxaban. aPCC was added to obtain 10 different concentrations ranging from 0.08-1.60 U/mL. Thromboelastometry and thrombin generation assay were used to assess the reversal effect. aPCC concentrations of 0.08 and 0.16 U/mL restored thromboelastometry clotting time to baseline in apixaban (P = 1.0) and rivaroxaban (P = 1.0)-containing samples, respectively. The concentrations 0.08 U/mL (P = 0.5) and 0.24 U/mL (P = 0.2) were sufficient to restore thrombin generation. Concentrations of 0.56 U/mL and higher, caused significantly higher ETP than baseline in apixaban-containing samples (P < 0.05). aPCC concentrations lower than previously reported were effective in reversing the effect of FXa inhibitors in vitro.

Factor VIII Inhibitor Bypassing Activity (FEIBA) Reversal for Apixaban and Rivaroxaban in Patients With Acute Intracranial and Nonintracranial Hemorrhage

BACKGROUND

The clinical use of factor VIII inhibitor bypassing activity (FEIBA) for factor Xa (FXa) inhibitor reversal is derived from small studies with notable variation in patient eligibility for use, dosage regimens, concurrent supportive care, and outcome measures. Consequently, additional effectiveness and safety data are warranted to expand the literature evaluating FEIBA for FXa inhibitor reversal.

OBJECTIVE

This study sought to determine the incidence of observed effective hemostasis within 24 hours of post-FEIBA® administration as well as in-hospital and 30-day post-discharge incidences of thromboembolic event (TEE) and mortality between apixaban and rivaroxaban in the intracranial hemorrhage (ICH) and non-ICH populations.

METHODS

This case series evaluated patients between January 1, 2014 through July 1, 2019 who received at least one FEIBA® dose for apixaban or rivaroxaban reversal secondary to acute ICH or non-ICH. Patient demographics, FEIBA® dosages, adjunct treatments, effectiveness, and safety outcomes were retrospectively collected from electronic medical record review. Modified hemostasis outcomes, adapted from criteria previously published by Sarode et al., TEE, and mortality between apixaban and rivaroxaban in the ICH and non-ICH populations were evaluated.

RESULTS

Among the 104 patients evaluated, 62 received apixaban and 42 rivaroxaban. Thirty apixaban and 25 rivaroxaban users experienced ICH, whereas 32 apixaban and 17 rivaroxaban users experienced non-ICH. Among the combined ICH and non-ICH populations, effective hemostasis occurred in 89%, TEE in 8%, and mortality in 13%. No statistically significant differences were observed within ICH and non-ICH populations receiving apixaban or rivaroxaban regarding effective hemostasis, TEE, or mortality.

CONCLUSION AND RELEVANCE

The combined ICH and non-ICH overall rates of effective hemostasis, TEE, and mortality were comparable to preexisting studies of FEIBA for factor Xa inhibitor reversal. The limitations inherent to the study design warrant a randomized controlled trial with an active comparator to confirm these observations.

Reversal Agents for the Direct Factor Xa Inhibitors: Biochemical Mechanisms of Current and Newly Emerging Therapies

The direct oral anticoagulants targeting coagulation factor Xa or thrombin are widely used as alternatives to vitamin K antagonists in the management of venous thromboembolism and nonvalvular atrial fibrillation. In case of bleeding or emergency surgery, reversal agents are helpful to counteract the anticoagulant therapy and restore hemostasis. While idarucizumab has been established as an antidote for the direct thrombin inhibitor dabigatran, reversal strategies for the direct factor Xa inhibitors have been a focal point in clinical care over the past years. In the absence of specific reversal agents, the off-label use of (activated) prothrombin complex concentrate and recombinant factor VIIa have been suggested as effective treatment options during inhibitor-induced bleeding complications. Meanwhile, several specific reversal agents have been developed. In this review, an overview of the current state of nonspecific and specific reversal agents for the direct factor Xa inhibitors is provided, focusing on the biochemistry and mechanism of action and the preclinical assessment of newly emerging therapies.

Activated prothrombin complex concentrates for direct oral anticoagulant-associated bleeding or urgent surgery: Hemostatic and thrombotic outcomes

INTRODUCTION

Studies evaluating the use of activated prothrombin complex concentrates (aPCCs) for DOAC-associated bleeding are sparse.

MATERIALS AND METHODS

We conducted a retrospective study of patients receiving aPCC for DOAC-associated bleeding or for pre-operative optimization of hemostasis prior to urgent surgery. The primary efficacy outcome was hemostatic efficacy, the primary safety outcome was the 30-day thromboembolic complication rate.

RESULTS

Eighty-two patients were included in the analysis; 14 patients on dabigatran, 39 patients on rivaroxaban and 29 patients on apixaban. Fifty-four patients received aPCC for major bleeding and 28 patients prior to urgent surgery. Mean aPCC dosing was 2974 IU (SD ± 857 IU). Hemostasis was deemed effective by ISTH criteria in 50% of cases and "Good" or "Moderate" by Sarode criteria in 45.2% and 14.3% of cases, respectively. Surgical hemostasis was rated as "Normal" in 84% of cases pre-operative administration. Median pre-aPCC INR was 1.6 (IQR 0.5) and median post-aPCC INR was 1.2 (IQR 0.2) (p < 0.00001). Median pre-aPCC aPTT was 36 s (IQR 12.8), median post-aPCC aPTT was 29 s (IQR 9.8) (p = 0.0001). The 30-day thromboembolic event rate was 6.1%.

CONCLUSION

Further study is needed to characterize the hemostatic effects and thromboembolic risk of aPCC among patients with DOAC-associated bleeding or for attempted normalization of hemostasis prior to urgent surgery.

Rivaroxaban Effects Illustrate the Underestimated Importance of Activated Platelets in Thrombin Generation Assessed by Calibrated Automated Thrombography

Background: The direct oral anticoagulant rivaroxaban inhibiting specifically activated factor X (FXa) causes delayed thrombin generation (TG) as measured by calibrated automated thrombography (CAT). The implications of these changes for assessing bleeding or residual prothrombotic risks of patients are unclear in the absence of a better understanding of the underlying mechanism. Methods: We compared platelet rich plasma (PRP) without or with prior collagen-induced platelet aggregation (agPRP) in the CAT assay to better characterize TG in the presence of rivaroxaban. Results: In the presence of rivaroxaban, TG curves in agPRP showed a distinct profile with a rapidly ascending phase followed with a protracted phase. Inhibition of tissue factor pathway inhibitor amplified the first phase of the curve which was also modulated by procoagulant phospholipids. Inhibition of FXIIa-dependent FXI activation revealed that aggregated platelets influenced the first phase by a combination of extrinsic and intrinsic coagulation pathway initiations. Thrombin-dependent amplification of TG (even prior collagen activation) was responsible for the second phase of the TG curve. Conclusions: AgPRP fully includes platelet ability to support TG and reveal distinct TG phases in the presence of direct FXa inhibitors highlighting its potential use in an anticoagulated setting.

Prothrombin Complex Concentrates for Perioperative Vitamin K Antagonist and Non-vitamin K Anticoagulant Reversal

Vitamin K antagonist therapy is associated with an increased bleeding risk, and clinicians often reverse anticoagulation in patients who require emergency surgical procedures. Current guidelines for rapid anticoagulation reversal for emergency surgery recommend four-factor prothrombin complex concentrate and vitamin K coadministration. The authors reviewed the current evidence on prothrombin complex concentrate treatment for vitamin K antagonist reversal in the perioperative setting, focusing on comparative studies and in the context of intracranial hemorrhage and cardiac surgery. The authors searched Cochrane Library and PubMed between January 2008 and December 2017 and retrieved 423 English-language papers, which they then screened for relevance to the perioperative setting; they identified 36 papers to include in this review. Prothrombin complex concentrate therapy was consistently shown to reduce international normalized ratio rapidly and control bleeding effectively. In comparative studies with plasma, prothrombin complex concentrate use was associated with a greater proportion of patients achieving target international normalized ratios rapidly, with improved hemostasis. No differences in thromboembolic event rates were seen between prothrombin complex concentrate and plasma, with prothrombin complex concentrate also demonstrating a lower risk of fluid overload events. Overall, the studies the authors reviewed support current recommendations favoring prothrombin complex concentrate therapy in patients requiring vitamin K antagonist reversal before emergency surgery.

Reversing anticoagulation in the hemorrhaging patient

PURPOSE OF REVIEW

Anticoagulants in general, but especially the relatively new direct oral anticoagulants and platelet inhibitors, pose a great challenge for physicians in the hemorrhaging patient. The aim of the present review is to provide an overview on recent studies dealing with the reversal of anticoagulation in the hemorrhaging patient and to describe our therapeutic emergency strategy for those patients.

RECENT FINDINGS

A specific antidote for dabigatran is already on the market and antidotes for the direct and indirect factor Xa inhibitors are in development. Moreover, bleeding under platelet inhibitors remains critical with very little evidence on effective reversal strategies.

SUMMARY

To reverse anticoagulation in the hemorrhaging patient, specific antidotes should be the first option if available, followed by four-factor prothrombin complex concentrate (PCC), activated PCC and recombinant activated factor seven as the emergency strategy. Fibrinogen concentrate, antifibrinolytics and oral charcoal, respectively, can be considered as an additional measure. Massive blood loss and thrombocytopenia should be treated independently according to the respective, local guidelines for (massive) transfusion of blood and blood products.

A Low-Dose 4F-PCC Protocol for DOAC-Associated Intracranial Hemorrhage

Purpose:

Current guidelines favor 4F-PCC over plasma for reversal of warfarin. Uncertainty remains on the hemostatic effectiveness and thrombotic risk of 4F-PCC for direct-acting oral anticoagulants (DOACs), particularly in patients with intracranial hemorrhage (ICH). This study sought to evaluate the effectiveness and safety of a lower dose protocol of 25 units/kg 4F-PCC for the management of DOAC-associated ICH in a real-world setting.

Materials and Methods:

This was a retrospective study of adult patients who received at least one dose of 4F-PCC from March 2014 to December 2015 for DOAC-associated ICH. The primary outcome was hemostatic effectiveness within 24 hours. The secondary outcome was thromboembolic events within 14 days.

Results:

Twenty-two patients received 4F-PCC for DOAC-associated ICH and were included in the analysis. Hemostasis was evaluable in 19 patients with post-4F-PCC imaging available and occurred in 18/19 (94.7%) patients. Thromboembolism occurred in 2 out of 22 patients (9.1%).

Conclusions:

The use of a lower dose protocol of 25 units/kg of 4F-PCC resulted in high rates of hemostasis in patients with DOAC-associated ICH. Two patients developed thrombotic events within 14 days of 4F-PCC administration.

The impact of prothrombin complex concentrates when treating DOAC-associated bleeding: a review

Background

Bleeding complications are a risk associated with all anticoagulants. Currently, the treatment options for the management of direct oral anticoagulant (DOAC)-associated bleeding are limited. Prothrombin complex concentrates (PCCs) have been proposed as a potential therapeutic option, and evidence regarding their use is increasing.

Review

Many studies supporting PCC have used preclinical models and healthy volunteers; however, more recently, observational studies have further improved insight into current DOAC reversal strategies. Multiple clinical practice guidelines now specifically suggest use of PCCs for this indication. Specific reversal agents for Factor Xa inhibitors may become available in the near future, but data on their efficacy are still emerging.

Conclusions

Ultimately, a multimodal approach may be the optimal strategy to restore haemostasis in patients presenting with DOAC-associated coagulopathy.

Electronic supplementary material

The online version of this article (10.1186/s12245-018-0215-6) contains supplementary material, which is available to authorized users.

Effect of low and moderate dose FEIBA to reverse major bleeding in patients on direct oral anticoagulants

OBJECTIVE

Management of acute, major or life threatening bleeding in the presence of direct acting oral anticoagulants (DOAC) is unclear. In the absence of a specific antidote, or in situations where there is a need for adjunctive therapy, the ideal prothrombin complex concentrate and dose is unclear. The goal of our study was to evaluate the outcomes of our reduced dosing strategy with FEIBA in patients experiencing a DOAC-related bleeding event.

DESIGN

Retrospective analysis of patients treated with FEIBA for a DOAC-related bleeding event.

SETTING

Academic medical center PATIENTS: Consecutive patients between May 2011 and April 2017 receiving FEIBA for a DOAC-related bleed INTERVENTIONS: None MEASUREMENTS & MAIN RESULTS: Of the 64 patients included in this analysis, 38 patients received low dose FEIBA (mean 10.0 ± 3.6 units/kg) and 26 received moderate dose (mean 24.3 ± 2.1 units/kg) FEIBA; an additional dose was requested in 6 patients. Six dabigatran patients received idarucizumab. 30 day event rates included 5 thromboembolic events (8%) and 9 (14%) patients expired. Follow-up CT-imaging for ICH, endoscopy/colonoscopy, or interventional radiology exams did not reveal any clinically concerning active bleeding or hematoma expansion except in 2 ICH patients with slight expansion between imaging sessions.

CONCLUSIONS

Low (<20 units/kg) to moderate (20-30 units/kg) doses of FEIBA, with the option for a repeat dose, may be an effective management strategy for obtaining hemostasis in DOAC-related major bleeding events.

Management of Intraoperative Coagulopathy

Intraoperative bleeding can be minimized with optimal preoperative preparation but cannot be completely prevented. There are circumstances when patients need emergent operative intervention, and thorough hemostatic evaluation and preparation is not possible. In this review, the authors summarize the recommendations for rapid reversal of vitamin K antagonists and direct oral anticoagulants before procedures. The authors review the potential causes for intraoperative bleeding and the methods for rapid and accurate diagnosis. The authors summarize the current evidence for treatment options, including transfusion of platelets and coagulation factors and the use of topical agents, antidotes to direct-acting anticoagulants, antifibrinolytics, and desmopressin.

Antidotes for the direct oral anticoagulants: What news?

The direct oral anticoagulants (DOACs) are recommended as the first-choice anticoagulants for both stroke prevention in patients with non-valvular atrial fibrillation and the treatment and secondary prevention of venous thromboembolism. DOACs cause bleeding, albeit less than warfarin. Most bleeding complications can be controlled by general reversal strategies and supportive care. However, in case of life-threatening bleeding, or when urgent invasive procedures are needed, a more rapid and thorough reversal may be required. Idarucizumab, andexanet alfa and ciraparantag have been developed as reversal agents for the DOACs. To date idarucizumab is the only approved antidote and is specific for dabigatran. Andexanet alfa, a reversal agent for the factor Xa inhibitors, is still under investigation, but its approval by regulatory agencies is expected soon. Ciraparantag, a universal antidote, is in an earlier stage of development. Based on the results of clinical trials to date, these compounds appear to be breakthrough for urgent and emergency reversal. When administered at fixed doses, they ensured a rapid, efficient and safe restoration of haemostasis. From a practical perspective, all hospitals should develop local protocols to ensure safe and efficient clinical implementation of reversal strategies. Post-marketing studies will be essential to assess the evolution of management strategies and to confirm the safety and effectiveness of these agents.

Advances in the Therapy of Bleeding Peptic Ulcer

Peptic ulcer bleeding remains an important medical emergency. Important recent advances are reviewed. These include further support for a more restrictive transfusion strategy aiming for a target haemoglobin of 70-90 g/L. The Glasgow-Blatchford score remains the most useful assessment score for identifying the lowest risk patients suitable for outpatient management and predicting the need for intervention. Newer scores such as the AIMS65 and Progetto Nazionale Emorragia Digestive score (PNED) may be more accurate in predicting mortality. Pre-endoscopy erythromycin improves outcomes and is underused. A new disposable Doppler probe appears to provide more accurate determination of both rebleeding risk and the success of endoscopic therapy than purely visual guidance. Over-the-scope clips and haemostatic powders appear to have some role as endoscopic salvage therapies. Non- H. pylori, non-aspirin/non-steroidal anti-inflammatory drug (NSAID) ulcers contribute to an increasing percentage of bleeding peptic ulcers and are associated with a high rebleeding rate. The optimal management of these ulcers remains to be determined.

Calibrated Automated Thrombinography (CAT), a Tool to Identify Patients at Risk of Bleeding during Anticoagulant Therapy: A Systematic Review

Background  Bleeding is a feared adverse event during anticoagulant treatment. In patients on vitamin K antagonists, most bleedings occur with the international normalized ratio (INR) in the therapeutic range. Currently, identification of high-risk patients via laboratory methods is not reliable. In this systematic review, we assessed the ability of calibrated automated thrombin generation (CAT-TG) to predict bleeding in patients on anticoagulant treatment. Methods  A systematic search was executed in three databases: Medline, Embase, and Cochrane. Results  Seven studies were included; two were of good methodological quality. One study showed that patients on warfarin with INRs in range (2-3) admitted for hemorrhage ( n  = 28), had lower CAT-TG levels (endogenous thrombin potential [ETP]: 333 ± 89 nM/min) than patients on warfarin admitted for other reasons (ETP: 436 ± 207 nM/min; p  < 0.001). Another study found no difference in ETP or peak levels between bleeding and nonbleeding patients in PPP or PRP. When measured in whole blood, both levels were significantly lower in patients with bleeding compared with nonbleeding patients (median [interquartile range, IQR] ETP: 182.5 [157.2-2,847 nM/min] vs. median [IQR] ETP: 256.2 [194.9-344.2 nM/min]; p  < 0.001) and median [IQR] peak: 23.9 [19.6-41.8 nM] vs. median [IQR] peak: 39.1 [24.9-53.2 nM]; p  < 0.05). From the remaining studies, four suggested that CAT-TG is more sensitive in detecting hemostatic abnormalities than INR and one article found ETP and INR to be equally useful. However, insufficient data were provided to validate these conclusions. Conclusion  Studies investigating the direct association between decreased CAT-TG values and hemorrhagic events are rare. Therefore, the clinical consequences of low CAT-TG values remain to be further investigated.

Safety of 4-factor prothrombin complex concentrate (4F-PCC) for emergent reversal of factor Xa inhibitors

Background

Although factor Xa inhibitors have become a popular choice for chronic oral anticoagulation, effective drug reversal remains difficult due to a lack of specific antidote. Currently, 4-factor prothrombin complex concentrate (4F-PCC) is considered the treatment of choice for factor Xa inhibitor-related major bleeding. However, safety of 4F-PCC and its risk of thrombosis when used for this off-label purpose remain unclear. The purpose of this retrospective study is to determine the rate of thromboembolism when 4F-PCC is used for the emergent reversal of factor Xa inhibitors.

Methods

We conducted a single-center retrospective review of medical records between 2013 and 2017. Patients were included if they received 4F-PCC to reverse rivaroxaban, apixaban, or edoxaban for emergent invasive procedures or during episodes of major bleeding defined as bleeding with hemodynamic instability, fall in hemoglobin of 2 g/dL, or bleeding requiring blood transfusion. Thrombotic events including myocardial infarction, pulmonary embolism, deep vein thrombosis, cerebral vascular accident, and arterial thrombosis of the limb or mesentery were recorded if they occurred within 14 days of 4F-PCC administration. Data was analyzed using point and interval estimation to approximate the rate and confidence interval of thromboembolic events.

Results

Forty-three patients were identified in our review. Doses of 4F-PCC were determined by the treating physician and mainly ranged from 25 to 50 IU/kg. Twenty-two patients (51.2%) received both sequential compression devices (SCDs) and subcutaneous heparin for DVT prophylaxis. Twenty-one patients (48.8%) were placed on SCDs only. Three patients received concomitant FFP. Thrombotic events within 14 days of 4F-PCC administration occurred in 1 out of 43 patients (2.1%, 95% CI [0.1–12.3]). This thrombotic event was an upper extremity DVT which occurred 1 day after the patient received 1325 IU (25 IU/kg) of 4F-PCC to reverse rivaroxaban for traumatic intracranial hemorrhage. The patient was taken for emergent decompressive craniotomy after rivaroxaban reversal. In patients who did not undergo surgery or who underwent minor invasive procedures, no thrombotic events were noted.

Conclusion

Based on our preliminary data, the thromboembolic rate of 4F-PCC when given at a dose of 25–50 IU/kg to emergently reverse rivaroxaban and apixaban appears acceptable. Since many patients who require 4F-PCC to emergently reverse factor Xa inhibitors will be at high risk of developing thrombotic events, practitioners should be highly vigilant of these complications. Large, multicenter prospective trials are needed to further determine this risk.

Activated prothrombin complex concentrate to reverse the factor Xa inhibitor (apixaban) effect before emergency surgery: a case series

BACKGROUND

The lack of an antidote against factor Xa inhibitors in case of major bleeding or need for urgent surgery is a concern to clinicians. Guidelines on managing major bleeding in patients under anticoagulation with a factor Xa inhibitor suggest several hemostatic agents to reverse the effect, but there is no consensus regarding the choice of drug or appropriate dose. The ability of prothrombin complex concentrate, activated prothrombin complex concentrate, and recombinant factor VIIa to reverse the effect of factor Xa inhibitors has been evaluated in animal studies, in vitro studies, and healthy volunteers, but not yet in randomized clinical studies.

CASE PRESENTATION

We report a consecutive case series of patients under factor Xa inhibitor (apixaban) treatment who received activated prothrombin complex concentrate to reverse the anticoagulation effect before emergency cardiovascular surgery. Patient 1, a 63-year-old white man, was operated with replacement of the aortic valve; patient 2, a 65-year-old white man, underwent heart transplantation; patient 3, a 68-year-old white man, was operated for acute type A aortic dissection. They all received activated prothrombin complex concentrate 25 IU/kg immediately before surgery. In two of the cases, the global coagulation assay thromboelastometry (ROTEM™) was performed before and after administering activated prothrombin complex concentrate. The ROTEM™ clotting time was reduced from 1900 seconds to 740 seconds and from 1482 to 807 seconds, respectively, after administering a dose of 25 IU/kg activated prothrombin complex concentrate. The apixaban concentration before reversal was within the range considered to be the therapeutic level in all cases. No bleeding complications occurred during surgery, but one case was complicated with bleeding postoperatively. No thromboembolic complications were observed during or after surgery.

CONCLUSIONS

Activated prothrombin complex concentrate 25 IU/kg reversed the anticoagulation effect of apixaban effectively and safely before emergency cardiovascular surgery.

Pharmacological reversal of the direct oral anticoagulants-A comprehensive review of the literature

The direct oral anticoagulants (DOACs) are used for stroke prevention in atrial fibrillation (SPAF) and the prevention and treatment of venous thromboembolic disease (VTE). Although DOAC-associated bleeding events are less frequent as compared to vitamin K antagonists, there is significant concern surrounding physicians' ability to evaluate and manage DOAC-associated bleeding when it does occur. Idarucizumab is a specific reversal agent for dabigatran and is the agent of choice for dabigatran reversal in the setting of major bleeding or urgent surgery/procedures. There are no commercially available specific reversal agents for the direct Xa inhibitors. Although they have not been rigorously studied in DOAC-treated patients requiring urgent anticoagulant reversal, limited evidence from in vitro studies, animal bleeding models, human volunteer studies (in vivo and in vitro) and case series suggest that coagulation factor replacement with prothrombin complex concentrate (PCC) and activated PCC (FEIBA) may contribute to hemostasis. However, the safety and efficacy of these agents and the optimal dosing strategies remain uncertain.

Pharmacologic Reversal of Direct Oral Anticoagulants

Direct oral anticoagulants are becoming increasingly popular in outpatient use. These medications have lacked specific reversal agents. However, this is changing. The Federal Food and Drug Administration approved idarucizumab for reversal of dabigatran in 2016, and another agent, andexanet alfa, is currently in clinical trials for reversal of rivaroxaban and apixaban. This article examines the efficacy and safety of these emerging reversal agents, as well as other historical agents for reversal of direct oral anticoagulants.

Recent advances in the management of peptic ulcer bleeding

Acute upper gastrointestinal haemorrhage due to peptic ulcer bleeding remains an important cause of emergency presentation and hospital admission. Despite advances in many aspects of management, peptic ulcer bleeding is still associated with significant morbidity, mortality, and healthcare costs. Comprehensive international guidelines have been published, but advances as well as controversies continue to evolve. Important recent advances include the evidence supporting a more restrictive transfusion strategy aiming for a target haemoglobin of 70–90 g/l. Comparative studies have confirmed that the Glasgow–Blatchford score remains the most useful score for predicting the need for intervention as well as for identifying the lowest-risk patients suitable for outpatient management. New scores, including the AIMS65 and Progetto Nazionale Emorragia Digestiva score, may be more accurate in predicting mortality. Pre-endoscopy erythromycin appears to improve outcomes and is probably underused. High-dose oral proton pump inhibition (PPI) for 11 days after PPI infusion is advantageous in those with a Rockall score of 6 or more. Oral is as effective as parenteral iron at restoring haemoglobin levels after a peptic ulcer bleed and both are superior to placebo in this respect. Within endoscopic techniques, haemostatic powders and over-the-scope clips can be used when other methods have failed. A disposable Doppler probe appears to provide more accurate determination of both rebleeding risk and the success of endoscopic therapy than purely visual guidance. Non- Helicobacter pylori, non-aspirin/non-steroidal anti-inflammatory drug ulcers contribute an increasing percentage of bleeding peptic ulcers and are associated with a poor prognosis and high rebleeding rate. The optimal management of these ulcers remains to be determined.

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).