Reversal of rivaroxaban and dabigatran by prothrombin complex concentrate: a randomized, placebo-controlled, crossover study in healthy subjects

Prothrombin complex concentrate for direct factor Xa inhibitor-associated bleeding or before urgent surgery

INTRODUCTION

Factor Xa inhibitor (FXaI)-associated bleeding events are common and associated with substantial morbidity. Systematic evaluation of widely available, effective, and affordable FXaI bleed management strategies is needed.

MATERIALS AND METHODS

We conducted a single-center retrospective cohort study of FXaI-treated patients presenting to a tertiary academic medical center from January 2018 to May 2019 who received 25-50 IU/kg 4F-PCC for either FXaI-associated major bleeding or urgent surgery. The primary outcome was hemostatic efficacy, and the safety outcome was the 30-day risk of thromboembolism.

RESULTS

PCC was used to treat FXaI-associated bleeding in 83 cases (79.1 %) and was given before urgent surgery in 22 cases (20.9 %). Sixty-six patients were on apixaban, 38 were on rivaroxaban and one patient was on edoxaban. Intracranial hemorrhage (ICH) and gastrointestinal bleeding accounted for most bleeds (74.7 %). Median interval between last DOAC intake and presentation to triage was 9 h [IQR 5.3-14.8] and median PCC dosing was 40.0 IU/kg [IQR 28.5-46.6]. Forty-two patients (40.0 %) had pre-PCC FXaI levels drawn with median FXaI levels of 114.5 ng/mL [IQR 70.0-175.0]. Effective hemostasis occurred in 66.7 % [95%CI 55.4-76.3] of patients receiving PCC for bleeding and surgical hemostasis was rated as normal in 95.5 % (95%CI 76.5-100.0) for patients having urgent surgery. The 30-day risk of thromboembolism was 7.6 % [95%CI 3.7-14.5] and 22.9 % [95%CI 15.8-31.8] of patients died.

CONCLUSIONS

PCC for FXaI-associated bleeding was associated with hemostatic efficacy in two-thirds of patients and thromboembolic events were uncommon. PCC represents a promising treatment strategy for FXaI-associated bleeding.

3-Factor prothrombin complex concentrate versus 4-factor prothrombin complex concentrate for the reversal of oral factor Xa inhibitors

Multiple agents exist for the reversal of oral Factor Xa inhibitor (FXa) associated bleeding, including Coagulation FXa Recombinant, Inactivated zhzo (andexanet alfa) and 4-factor prothrombin complex concentrate (4F-PCC). While classified as a 3F-PCC product, Profilnine contains up to 35 IU of Factor VII (per 100 IU of Factor IX) in addition to therapeutic levels of Factors II, IX, and X, and has demonstrated a similar impact on prothrombin time and blood product usage in non-warfarin related bleeding. This was a retrospective, multicenter study at four medical centers of adult patients who presented with major bleeding associated with oral FXa inhibitors and received either 4F-PCC (n = 64) or 3F-PCC (n = 61). The primary outcome was hemostatic effectiveness. Secondary outcomes included the incidence of thromboembolism, in-hospital mortality, and length of stay. The most common indication for reversal was intracranial bleeding. For the primary outcome, 84% of all patients were rated as effective with no difference noted between the groups (p = 0.81). No significant difference between groups was found in the multivariable analysis adjusting for baseline differences between groups including race, total body weight, type of bleeding, and the use of antiplatelet therapy. There was no difference in the length of stay, in-hospital mortality, or the incidence of thromboembolism between the groups. Overall, no significant differences were found in the effectiveness or safety of 4F-PCC and 3F-PCC use in the management of oral FXa inhibitor-associated bleeding. Further investigations are warranted to explore the use of 3F-PCC for this indication and its safety and effectiveness.

Four-factor prothrombin complex concentrate is not inferior to andexanet alfa for the reversal or oral factor Xa inhibitors: An Eastern Association for the Surgery of Trauma multicenter study

BACKGROUND

Andexanet alfa (AA) is the only FDA-approved reversal agent for apixaban and rivaroxaban (DOAC). There are no studies comparing its efficacy with four-factor prothrombin complex concentrate (PCC). This study aimed to compare PCC to AA for DOAC reversal, hypothesizing noninferiority of PCC.

METHODS

We performed a retrospective, noninferiority multicenter study of adult patients admitted from July 1, 2018, to December 31, 2019, who had taken a DOAC within 12 hours of injury, were transfused red blood cells (RBCs) or had traumatic brain injury, and received AA or PCC. Primary outcome was PRBC unit transfusion. Secondary outcome with intensive care unit length of stay. MICE imputation was used to account for missing data and zero-inflated Poisson regression was used to account for an excess of zero units of RBC transfused. Two units difference in RBC transfusion was selected as noninferior.

RESULTS

Results: From 263 patients at 10 centers, 77 (29%) received PCC and 186 (71%) AA. Patients had similar transfusion rates across reversal treatment groups (23.7% AA vs. 19.5% PCC) with median transfusion in both groups of 0 RBC. According to the Poisson component, PCC increases the amount of RBC transfusion by 1.02 times (95% confidence interval, 0.79-1.33) compared with AA after adjusting for other covariates. The average amount of RBC transfusion (nonzero group) is 6.13. Multiplying this number by the estimated rate ratio, PCC is estimated to have an increase RBC transfusion by 0.123 (95% confidence interval, 0.53-2.02) units compared with AA.

CONCLUSION

PCC appears noninferior to AA for reversal of DOACs for RBC transfusion in traumatically injured patients. Additional prospective, randomized trials are necessary to compare PCC and AA for the treatment of hemorrhage in injured patients on DOACs.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

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.

Latest advances in the reversal strategies for direct oral anticoagulants

BACKGROUND

Since the late 2000s, Europe has granted approval for various thrombotic risk-related uses of direct oral anticoagulants (DOACs). Unlike traditional anticoagulants, DOACs do not necessitate routine coagulation monitoring. Nevertheless, clinical practice often encounters bleeding events associated with these medications, making the need for effective reversal strategies evident.

OBJECTIVES

The study aims to take stock of current reversal strategies for DOACs, with a particular emphasis on the latest compounds that have been developed or are currently under development.

METHODS

For obtaining information regarding the ongoing reversal strategies and the compounds under development, we referred to ClinicalTrials website, PubMed, and Google Scholar.

RESULTS

In 2024, two specific antidotes to DOACs have already received approval when reversal of anticoagulation is needed owing to life-threatening or uncontrolled bleeding: idarucizumab that reverses the effects of dabigatran, and andexanet alfa, designed to counteract activated factor X inhibitors such as apixaban and rivaroxaban. Furthermore, ciraparantag, a potential universal reversal agent, is currently in advanced stages of clinical development. Concerns remain regarding the safety of specific reversal agents, especially concerning the risk of thrombosis. Additionally, the cost of these antidotes remains high. Consequently, nonspecific strategies to counteract anticoagulant medications, including activated charcoal, hemodialysis, and concentrates of coagulation factors, still have utility.

CONCLUSION

With the validation of specific and nonspecific antidotes, DOACs could supplant traditional oral anticoagulants. This progress represents a significant advancement in anticoagulation therapy. However, ongoing research is crucial to address remaining safety concerns of the specific reversion agents of DOACs in clinical practice.

Reversal and resumption of anticoagulants in patients with anticoagulant-associated intracerebral hemorrhage

The use of anticoagulants has become more frequent due to the progressive aging population and increased thromboembolic events. Consequently, the proportion of anticoagulant-associated intracerebral hemorrhage (AAICH) in stroke patients is gradually increasing. Compared with intracerebral hemorrhage (ICH) patients without coagulopathy, patients with AAICH may have larger hematomas, worse prognoses, and higher mortality. Given the need for anticoagulant reversal and resumption, the management of AAICH differs from that of conventional medical or surgical treatments for ICH, and it is more specific. Understanding the pharmacology of anticoagulants and identifying agents that can reverse their effects in the early stages are crucial for treating life-threatening AAICH. When patients transition beyond the acute phase and their vital signs stabilize, it is important to consider resuming anticoagulants at the right time to prevent the occurrence of further thromboembolism. However, the timing and strategy for reversing and resuming anticoagulants are still in a dilemma. Herein, we summarize the important clinical studies, reviews, and related guidelines published in the past few years that focus on the reversal and resumption of anticoagulants in AAICH patients to help implement decisive diagnosis and treatment strategies in the clinical setting.

4-Factor Prothrombin Complex Concentrate Dosing Strategies: A Retrospective Evaluation

ObjectivesDetermine indication specific 4-Factor prothrombin complex concentrate (4FPCC) dosing strategies within a hospital system and subsequent effectiveness. Background: 4FPCC is FDA approved for reversal of vitamin K antagonists (VKA) for acute major bleeding or need for urgent surgery/invasive procedure. Since its approval, off label use has expanded to include direct oral anticoagulant reversal and perioperative hemostasis. Optimal dosing strategies remain controversial, and recent studies have evaluated fixed-dose regimens with lower doses than those recommended in product labeling. Methods/Materials: Retrospective cohort with manual chart review for patients who received 4FPCC spanning 2 years. Primary outcome was to characterize dosing. Secondary outcomes were INR normalization, hemostatic efficacy, in-hospital mortality, and renal function change. Results: Of the 300 patients evaluated, 80% received 4FPCC for anticoagulant reversal, with 66% of those for VKA and 34% for DOAC. The remaining 20% received 4FPCC for a non-reversal indication. Of the patients requiring anticoagulation reversal, 25% received doses lower than recommended and 6% received higher. 71% of patients received 4FPCC for life-threatening bleed, and 45% of them had intracranial hemorrhage. Higher mortality with higher than recommended doses was the only statistically significant secondary outcome (P = .018). Conclusion: We found that lower doses than recommended were used in a significant number of patients. The higher than recommended doses group constituted a small proportion of patients and the higher mortality was attributed to patient acuity on presentation. Additional studies evaluating dosing approach are required to determine lowest effective dosing for various indications.

Non-traumatic Spinal Subdural Hemorrhage Associated With Rivaroxaban Use

Spinal subdural hematoma (SSDH) is a rare medical emergency that can cause permanent neurological deficits. The disease is characterized by sudden onset back pain, sensorimotor changes, and bladder and autonomic dysfunction. This is often associated with the use of anticoagulants, blood dyscrasias, and recent spinal procedures. We present a case of a 63-year-old male maintained on rivaroxaban for nonvalvular atrial fibrillation clinically presenting with abrupt onset back pain that rapidly progressed to sensorimotor deficits and bladder dysfunction. Rivaroxaban, a selective inhibitor of factor Xa, has been approved by the Food and Drug Administration (FDA) for the reduction of stroke risk and systemic embolism in nonvalvular atrial fibrillation. We postulate that rivaroxaban played a major role in triggering the spinal hemorrhage. This case highlights the very limited documented cases of spontaneous subdural spinal hemorrhages associated with rivaroxaban use.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Comparison of outcomes for fixed and weight-based four-factor prothrombin complex concentrate dosing regimens

OBJECTIVES

Although fixed dose regimens using four-factor prothrombin complex concentrate (4F-PCC) are more widely accepted, using a 'one size fits all' approach remains an area of uncertainty. The primary objective of this study was to compare percentages of haemostasis between fixed dose and weight-based dose 4F-PCC regimens for multiple bleed types and anticoagulants. Secondary objectives compared differences in the time to administration and in-hospital mortality.

METHODS

This retrospective, cohort study took place at a community hospital and included patients ≥18 years of age receiving 4F-PCC for major bleeding while on either warfarin or a factor-Xa inhibitor between January 2015 and December 2022. Patients received either fixed dose (treatment) or weight-based dose (comparison). Patients who had been treated for a non-urgent procedure, with unknown haemorrhage source, not on anticoagulation, coagulopathic from hepatic failure, had received dabigatran or were allergic to heparin were excluded. Fisher's exact test and logistic regression were used to analyse primary and secondary outcomes.

RESULTS

94 patients met the inclusion criteria; 38 patients were assigned to the treatment group and 56 to the comparator group. There was no statistical evidence of a difference in the achievement of haemostasis between groups (45% vs 46%, p=0.872). The fixed dose patients received the dose on average 13 min faster than weight-based (32 min vs 46 min, p=0.031). There was no difference in mortality (29% vs 29%, p=0.968).

CONCLUSION

Fixed 4F-PCC regimens may achieve similar outcomes and a faster time to administration compared with weight-based regimens.

Clinical Relevance of Preclinical and Clinical Studies of Four-Factor Prothrombin Complex Concentrate for Treatment of Bleeding Related to Direct Oral Anticoagulants

Direct oral anticoagulants (DOACs) are widely used for the prevention and treatment of venous thromboembolism and stroke. When emergency reversal of DOAC-related anticoagulation is required, specific DOAC reversal agents are recommended, including idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. However, specific reversal agents are not always available, andexanet alfa has not been approved for urgent surgery, and clinicians need to know the patient's anticoagulant medication before administering these treatments. Four-factor prothrombin complex concentrates (4F-PCCs) are recognized as nonspecific, alternative hemostatic agents for treatment of DOAC-related bleeding. Evidence from preclinical and clinical studies shows that they may reduce the anticoagulant effects of DOACs and may help control DOAC-related bleeding. However, randomized controlled trials are lacking, and most data are from retrospective or single-arm prospective studies in bleeding associated with activated factor X inhibitors. There are no clinical data showing the efficacy of 4F-PCC for the treatment of bleeding in dabigatran-treated patients. This review focuses on the current evidence of 4F-PCC use in controlling bleeding associated with DOACs and provides an expert opinion on the relevance of these data for clinical practice. The current treatment landscape, unmet needs, and future directions are also discussed.

Recommendations for the use of andexanet alfa in the management of bleeding in patients on oral factor Xa inhibitors in Switzerland: Guideline from the Working Party Hemostasis of the Swiss Society of Hematology

Anticoagulants are essential in preventing and treating thrombosis. Unfortunately, their use is accompanied by an enhanced risk of bleeding. Since the introduction of direct oral anticoagulants (DOACs), the risk of major bleeding has been reduced but not eliminated. Major bleeding events related to the use of factor Xa inhibitors can be challenging to manage. In recent years, four-factor prothrombin complex concentrates have been used in patients with severe bleeding taking oral direct factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). Andexanet alfa (OndexxyaTM, AstraZeneca AG) is a specially designed recombinant version of human factor Xa that acts as a decoy receptor to reverse the effects of factor Xa inhibitors. Since 2 December 2020, andexanet alfa has been used in Switzerland for adult patients receiving apixaban or rivaroxaban when reversal of anticoagulation is required because of life-threatening or uncontrolled bleeding. However, the use of andexanet alfa remains a challenge owing to its cost, the reported thrombotic complications and the fact that its efficacy mainly relates to intracranial haemorrhage. Moreover, the use of nonspecific reversal agents together with andexanet alfa is controversial. The present recommendations on the use of andexanet alfa in the management of bleeding in patients on factor Xa inhibitors in Switzerland were developed by a group of Swiss experts from the Working Party Hemostasis of the Swiss Society of Hematology. These recommendations aim to provide support to clinicians in their decision-making in the management of patients with major bleeding receiving factor Xa inhibitors.

Effect of PCC on Thrombin Generation among Patients on Factor Xa Inhibitors with Major Bleeding or Needing Urgent Surgery (GAUGE): Design and Rationale

Background  Direct factor Xa inhibitors (FXaIs) account for most oral anticoagulant use and FXaI-associated bleeding events are common. Clinicians have variable national and regional access to specific FXaI reversal agents such as andexanet alfa. Many centers have adopted the use of prothrombin complex concentrates (PCCs) as hemostatic therapy for FXaI-associated major bleeding events. PCC does not impact circulating FXaI levels and its mechanism of action to achieve hemostasis in FXaI-associated bleeding is uncertain. While PCC increases quantitative thrombin generation assay (TGA) parameters, it does not correct FXaI-altered thrombin generation kinetics, nor does it normalize thrombin generation. Clinical data supporting the use of PCC are based on cohort studies reporting clinical hemostatic efficacy, which is difficult to measure. The benefits of PCC for FXaI-associated bleeding beyond supportive care are uncertain. Objective  GAUGE is a prospective observational study designed to measure the effects of four-factor PCC administration (Octaplex) on TGA parameters among patients with FXaI-associated bleeding or needing urgent surgery. Methods  Laboratory outcomes will include the mean paired change in TGA parameters from pre- to post-PCC administration and the proportion of participants whose post-PCC TGA values fall within a defined reference range. Clinical outcomes will include hemostatic efficacy, thromboembolic complications, and all-cause death at 30 days post-PCC. Conclusion  Development of a viable and universally accessible FXaI bleed management strategy is crucial. GAUGE will provide in vivo data on the effects of PCC among patients with FXaI-associated bleeding.

Real-world clinical outcomes among US Veterans with oral factor xa inhibitor-related major bleeding treated with andexanet alfa or 4-factor prothrombin complex concentrate

Oral factor Xa (FXa) inhibitors significantly reduce incidence of stroke and thromboembolic events in patients with atrial fibrillation or venous thromboembolism. Due to various factors and the lack of a randomized controlled trial comparing andexanet alfa to usual care, non-specific replacement agents including 4 F-PCC are still used off-label for FXa inhibitor bleed management. Clinical and mortality data were extracted from the inpatient medical data and Veteran Affairs (VA) vital status files over the time of March 2014 through December 2020. Propensity score-weighted models were used for this retrospective cohort study using data from the Veterans Affairs Informatics and Computing Infrastructure (VINCI). The study included 255 patients (85-andexanet alfa and 170-4 F-PCC) exposed to an oral factor Xa inhibitor and hospitalized with an acute major, gastrointestinal (GI), intracranial (ICH) or other bleed. In-hospital mortality was significantly lower in the andexanet alfa cohort compared to the 4 F-PCC cohort (10.6% vs. 25.3%, p = 0.01). Propensity score-weighted Cox models reveal a 69% lower hazard of in-hospital mortality for those treated with andexanet alfa (HR 0.31, 95% CI 0.14-0.71) compared to those treated with 4 F-PCC. Additionally, those treated with andexanet alfa had a lower 30-day mortality rate and lower 30-day hazard of mortality in the weighted Cox model (20.0% vs. 32.4%, p = 0.055; HR 0.54, 95% CI 0.30-0.98) compared to those treated with 4 F-PCC. Among 255 US veterans with major bleeding in the presence of an oral factor Xa inhibitor, treatment with andexanet alfa was associated with lower in-hospital and 30-day mortality than treatment with 4 F-PCC.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Thrombin generation in real life bleeding patients on oral anticoagulants reversed (or not) with (activated) prothrombin complex concentrate

BACKGROUND

Bleeding during oral anticoagulant therapy is currently codified by expert guidelines. Monitoring of coagulation during bleeding events is challenging. Our study sought to assess thrombin generation assay (TGA) in direct oral anticoagulant-treated patients without bleeding (WB), bleeding without reversal therapy (BR-), and bleeding with reversal therapy (BR+).

METHODS

We conducted a prospective, monocentric study from June 2015 to June 2018. For all bleeding groups, TGA was evaluated using platelet-poor plasma collected upon arrival at emergency (T0), and 30 min (T1), 6 h (T2) and 24 h (T3) after reversal therapy (if indicated) following activation by tissue factor 5 pM and phospholipids.

RESULTS

Overall, 292 patients participated, including 91 BR+, 94 BR-, and 107 WB patients. At T0, vitamin K antagonist reversed (VKA-BR+) patients experienced a significant decrease in TGA parameters (ETP and peak) compared with VKA without bleeding (VKA-WB). Compared with healthy controls, VKA-BR+ patients reversed by four-factor prothrombin complex concentrate (4F-PCC) displayed comparable TGA 's ETP and peak at T1, T2, and T3, whereas direct anti-Xa BR+ patients reversed by 4F-PCC or activated prothrombin complex concentrate (aPCC) reached thrombin generation parameters that exceeded normal range at T2 and T3.

CONCLUSIONS

In VKA-treated patients reversed by 4F-PCC, TGA parameters were normalized, whereas in rivaroxaban or apixaban-treated patients reversed by 4F-PCC or aPCC, TGA parameters exceeded normal range. Further studies are needed to compare the efficacy and safety of a different dose of reversal therapy and the impact on coagulation parameters.

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.

Outcomes of 4-factor Prothrombin Complex Concentrate in Patients With Liver Disease and Nonvitamin K Antagonist-Related Coagulopathy: A Retrospective Study

The administration of 4-factor prothrombin complex concentrate (4F-PCC) has expanded beyond its Food and Drug Administration (FDA)-approved indication for the emergent reversal of vitamin K antagonists (VKAs). Therefore, this study aimed to evaluate the risks and benefits associated with the expanded use of 4F-PCC. We conducted a single-center retrospective review of 4F-PCC administrations at our university hospital. Of the 159 patients who received 4F-PCC, 76% (n = 121) and 24% (n = 38) received it for the FDA-approved indication in the vitamin K-related coagulopathy (VKA) group and for expanded use in the nonvitamin K-related coagulopathy (nVKA) group, respectively. The expanded use of 4F-PCC was associated with a less robust reduction in the international normalized ratio (INR) (INR of -0.7 ± 1.3 vs INR of -1.6 ± 1.8, P = .002), and fewer patients in the nVKA group achieved a postadministration INR of less than1.5 (11% vs 79%, P = .001) than those in the VKA group. Furthermore, the 30-day mortality rate was significantly higher in the nVKA cohort than in the VKA cohort (42% vs 20%, P = .04). Notably, based on our data, underlying differences in the patient's comorbidities, particularly advanced liver disease, may have contributed to the observed outcome variations, including mortality rate. Therefore, factors, including comorbidities and the underlying etiology of coagulopathy, should be considered when deciding on the expanded use of 4F-PCC. Further research is needed to better understand the potential risks and benefits of 4F-PCC in expanded use scenarios, and the clinical decision to use 4F-PCC outside its FDA-approved indication should be made carefully, considering this information.

Patient factors associated with receiving reversal therapy in oral anticoagulant-related intracerebral hemorrhage

BACKGROUND

We aimed to describe baseline characteristics of patients with oral anticoagulant-related intracerebral hemorrhage (OAC-ICH) in Sweden and to identify predictive variables associated with receiving hemostatic treatment in the event of OAC-ICH.

METHODS

We performed an observational study based on data from Riksstroke and the Swedish Causes of Death Register to define baseline characteristics of patients with OAC-ICH who received reversal treatment compared with patients who did not receive reversal treatment during 2017-2019. Predictive analysis was performed using multivariable logistic regression to identify odds ratios for factors associated with receiving OAC reversal treatment.

RESULTS

We included 1902 patients ((n = 1146; OAC reversal treatment) (n = 756; no OAC reversal treatment)). The proportion of non-Vitamin K oral anticoagulant associated ICH (NOAC-ICH) patients who received reversal treatment was 48.4% and the proportion of Vitamin K antagonist-associated ICH (VKA-ICH) patients was 72.9%. Factors associated with a lower odds of receiving reversal treatment were increased age (OR = 0.98; 95% CI: 0.96-0.99), previous stroke (OR = 0.78; 95% CI: 0.62-0.98), comatose LOC (OR = 0.36;95%CI: 0.27-0.48; ref. = alert), pre-stroke dependency (OR = 0.72; 95% CI: 0.58-0.91), and NOAC treatment (OR = 0.34; 95% CI: 0.28-0.42). Care at a university hospital was not associated with higher odds of receiving reversal treatment compared to treatment at a county hospital.

CONCLUSION

Treatment with a reversal agent following OAC-ICH was related to several patient factors including type of OAC drug. We identified that only 48% of patients with NOAC-ICH received hemostatic treatment despite an increase in these cases. Further studies are required to guide the use of reversal therapies more precisely, particularly in NOAC-ICH.

Direct Oral Anticoagulant Reversal in the Pediatric Emergency Department

ABSTRACT

Direct oral anticoagulants have been used in the adult population for years and are being used more frequently in pediatrics. Direct oral anticoagulants are chosen preferentially because they do not require close outpatient monitoring, have an equal or better safety profile, and are easy for patients to take. Warfarin is the previous, more commonly used oral anticoagulant and acts as a vitamin K antagonist. Direct oral anticoagulants mechanism of action is different in that they directly inhibit part of the coagulation cascade accomplishing the same end goal. Given their differing mechanisms, they require alternate medications for proper reversal when concerned about overdose of life-threatening bleeds. This review will outline the most commonly used direct oral anticoagulants in pediatric populations and the supporting (mainly adult) data available for proper reversal of these medications in times of need.

Sequential low molecular weight heparin and rivaroxaban for venous thromboprophylaxis in pelvic and acetabular trauma

INTRODUCTION

Patients with pelvic trauma are at high risk of thromboembolic complications, but effective methods of prophylaxis are still to be accepted widely. The incidence of venous thromboembolism (VTE) has been reported to be as high as 61%, which represents the commonest cause of morbidity and mortality in this cohort. New oral anticoagulants are now available and may be used instead of LMWH injections for extended prophylaxis. Rivaroxaban has not been comprehensively considered in the previous pelvic and acetabular trauma literature, but its known benefits include increased patient compliance, especially in the minority of patients who are unable to self-administer injections, and that it does not require monitoring.

MATERIALS AND METHODS

All patients referred to our pelvic trauma service between 2015 and 2020 were considered for this study, exclusion criteria involved those patients who had contraindications to rivaroxaban, those who were referred to our service but were never managed at our centre and those managed by other teams (e.g. neurosurgery). Operative patients were initially managed with LMWH until 24 h post-operatively when they started rivaroxaban. Conservatively managed patients started Rivaroxaban straight away. Data were collected on demographics, injury mechanism, fracture classification and clinically relevant VTE and bleeding events up until 3 months post discharge.

RESULTS

The overall incidence of VTE was 2%. These represented 3 DVTs and 3 PEs, and occurred in patients who were managed operatively. No major bleeding events were observed. There were two minor bleeding events, both occurring in patients who were managed conservatively with rivaroxaban alone, and they did not require further intervention. 90% of patients surveyed expressed preference for oral prophylaxis. Reported compliance with rivaroxaban was 100%.

CONCLUSION

Our data show that this VTE regimen protocol is safe and effective in this group of injured patients and is at least non-inferior to the standard prophylaxis of LMWH alone.

A short review of ciraparantag in perspective of the currently available anticoagulant reversal agents

Despite the improved safety-profile of direct oral anticoagulants (DOACs), bleeding complications remain an important side effect of anticoagulant treatment. Although anticoagulant-specific antidotes are available, an universal anticoagulant reversal agent in case of life-threatening bleeding or emergency surgery is not yet available. Ciraparantag, a synthetic small molecule that inactivates heparins and DOAC, is a promising new reversal agent that has been investigated in phase 2 trials. In this short review we provide an overview of the preclinical and clinical evidence of ciraparantag, and compare strengths and weaknesses of ciraparantag and the currently available anticoagulant reversal strategies.

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.

Pharmacotherapy for pulmonary embolism: new anticoagulants

Background: Pulmonary embolism is associated with reduced survival and considerable economic burden worldwide. In Korea, the incidence of pulmonary embolism has been gradually increasing. Older individuals are at an increased risk for pulmonary embolism and anticoagulation-related bleeding events. Typically, heparin and vitamin K antagonists are employed to treat pulmonary embolism; however, these agents present numerous limitations. Hence, novel anticoagulants with improved safety and efficacy profiles are urgently needed.Current Concepts: Direct oral anticoagulants (DOACs), including direct thrombin (coagulation factor II) inhibitors and selective inhibitors of coagulation factor Xa, have emerged as alternative agents. Phase III, large-scale clinical trials have revealed that DOACs are non-inferior to standard therapy during initial and long-term treatment of pulmonary embolism, considering the safety profile. Evidence-based clinical guidelines recommend that primary care clinicians employ DOACs over warfarin to achieve anticoagulation.Discussion and Conclusion: For over 70 years, the standard therapy for most patients with pulmonary embolism has involved heparin administration, overlapped and followed by a vitamin K antagonist. Recently developed DOACs against coagulation factor Xa or thrombin might overcome limitations of standard therapy, including the need for injection and regular dose adjustment with laboratory monitoring. These limitations hinder the management of patients with pulmonary embolism and negatively impact the patient’s quality of life. Four DOACs, including apixaban, dabigatran, edoxaban, and rivaroxaban, are currently available for treating pulmonary embolism in Korea, which could simplify the therapeutic strategy.

In vitro reversal of direct factor Xa inhibitors: Direct comparison of andexanet alfa and prothrombin complex concentrates Cofact and Beriplex/Kcentra

Background

Both andexanet alfa and four-factor prothrombin complex concentrate (4F-PCC) are clinically applied reversal agents for direct factor Xa inhibitors (FXaIs) in emergency situations. Controversy exists whether 4F-PCC is as effective as andexanet alfa in correcting FXaI anticoagulation.

Objective

This in vitro study was designed to directly compare andexanet alfa with two different 4F-PCCs (Cofact and Beriplex/Kcentra) in their ability to correct FXaI anticoagulation.

Method

Normal plasma was spiked with apixaban or rivaroxaban. Reversal of anticoagulation was assessed using a thrombin generation assay and a fibrin generation-clot lysis test.

Results

Andexanet alfa, applied at clinically recommended doses, was effective in restoring thrombin generation as evidenced by correction of thrombin generation lag time, peak thrombin, and endogenous thrombin potential (ETP). Clotting time and clot resistance to fibrinolytic breakdown was corrected over the full range of applied FXaI (0-800 ng/ml). 4F-PCC in increasing doses (0.625, 1.25 and 2 IU/ml; approximately 25, 50, and 80 IU/kg) only partially restored thrombin generation lag time and clotting time. Partial correction to overnormalization of peak thrombin and ETP was observed, depending on FXaI concentration and PCC dose. Clot resistance to fibrinolytic breakdown was dose-dependently improved to above normal. Beriplex/Kcentra was consistently less effective than Cofact.

Conclusion

Both andexanet alfa and 4F-PCC improved coagulation that is hampered by FXaIs. While andexanet alfa corrected all thrombin generation parameters, 4F-PCC predominantly increased peak thrombin and ETP. Especially heparin-free 4F-PCC also improved clot stability against fibrinolytic breakdown. Beriplex/Kcentra contains heparin, and this may have caused reduced effectivity compared to Cofact.

Role of Direct Oral Anticoagulants for Post-operative Venous Thromboembolism Prophylaxis

Venous thromboembolism (VTE) is one of the leading causes of post-operative morbidity and mortality. Over previous decades, heparin and warfarin were the predominant therapeutic options for post-operative thromboprophylaxis. However, their use is limited by drawbacks including a narrow therapeutic range, numerous food and drug interactions, and the need for regular monitoring for dose adjustments. Recently, direct oral anticoagulants (DOACs), such as dabigatran etexilate (a direct thrombin inhibitor) and apixaban, rivaroxaban and edoxaban (direct factor Xa inhibitors), have been developed to overcome these issues. DOACs have shown promising results in Phase III clinical trials for post-operative VTE prophylaxis. This review summarises the pharmacological profile of DOACs and highlights the use of DOACs in post-operative VTE prophylaxis based on the available clinical trial data.

Reversing direct factor Xa or thrombin inhibitors: Factor V addition to prothrombin complex concentrate is beneficial in vitro

Background

Prothrombin complex concentrate (PCC) is a human plasma‐derived mixture of partially purified vitamin K‐dependent coagulation factors (VKCF). Current therapeutic indication is treatment and perioperative prophylaxis of bleeding in acquired VKCF deficiency. Off‐label uses include treatment of direct factor Xa‐ or thrombin inhibitor‐associated bleeds, treatment of trauma‐induced coagulopathy, and hemorrhagic complications in patients with liver disease.

Objective

Considering PCC as a general prohemostatic drug, we argued that its clinical efficacy can benefit from supplementation with coagulation factors that are absent in the current PCC formulation. In this study, we focused on factor V.

Methods

We mimicked a coagulopathy in vitro by spiking whole blood or derived plasma with the direct oral anticoagulants (DOAC) rivaroxaban or dabigatran. We studied DOAC reversal by PCC and factor V concentrate (FVC) using a thrombin generation assay, thromboelastography, fibrin generation clot lysis test, and microfluidic thrombus formation under flow.

Results

In DOAC‐treated plasma, PCC increased the amount of thrombin generated. The addition of FVC alone or in combination with PCC caused a partial correction of the thrombin generation lag time and clotting time. In DOAC‐treated whole blood, the combination of PCC and FVC synergistically improved clotting time under static conditions, whereas complete correction of fibrin formation was observed under flow. Clot strength and clot resistance toward tissue plasminogen activator‐induced lysis were both increased with PCC and further enhanced by additional FVC.

Conclusion

Our in vitro study demonstrates a beneficial effect of the combined use of PCC and FVC in DOAC reversal.

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.

Andexanet Alfa Versus Prothrombin Complex Concentrates/Blood Products as Apixaban/Rivaroxaban Reversal Agents: A Survey Among Pediatric Hematologists

Direct oral factor Xa inhibitors (DXIs) are approved for use in adult patients with non-valvular heart disease for stroke prevention, and the treatment/prevention of venous thromboembolism (VTE). Recent pediatric clinical trials have demonstrated safety and efficacy of direct oral anticoagulants (DOACs) in the treatment of VTE. However, there is a lack of evidence regarding the use of andexanet alfa and prothrombin complex concentrates (PCC) for anticoagulation reversal of DXIs in the pediatric population. To better understand current DXI reversal strategies in this age group, a 10-question survey was conducted among pediatric hematology members of the Hemostasis and Thrombosis Research Society. Seventeen percent completed the survey (27 of 163 pediatric hematology members) with 74% (n = 20) reporting their use of DXIs for the treatment and prevention of VTE. Forty-four percent (n = 12) would choose andexanet alfa as first-line treatment for life-threatening bleeding while 52% (n = 14) would use PCC first with one individual choosing recombinant factor VII for DXI reversal. Clinical studies of andexanet alfa and PCC for the management of DXI-associated life-threatening bleeding require further investigation in the pediatric population.

High-dose versus low-dose 4-factor prothrombin complex concentrate for factor Xa inhibitor reversal in intracranial hemorrhage

BACKGROUND & PURPOSE

4-factor prothrombin complex concentrate (4FPCC) is used off-label for factor Xa (FXa) inhibitor-associated intracranial hemorrhage (ICH). Guideline recommendations provide various 4FPCC dosing regimens for FXa inhibitor reversal in this setting. We evaluated 4FPCC weight-based dosing and outcomes in FXa inhibitor-associated ICH.

METHODS

We conducted a multi-center, retrospective, cohort study of ICH patients between July 2017 and February 2020. Patients were greater than 18 years of age, received 4FPCC, and were taking apixaban, rivaroxaban, or edoxaban. Patients were separated into high- (≥35 units/kg) or low-dose (<35 units/kg) 4FPCC groups. The primary outcome was hemostasis achievement. Secondary outcomes included in-hospital mortality, intensive care unit and hospital length of stay, discharge disposition, and thrombotic events. Outcomes were evaluated with binary logistic regression.

RESULTS

Of 390 patients identified, 89 were included with 74 and 15 in the high- vs low-dose groups, respectively. Mean (SD) age was 76.6 (±10.8) years. Most were taking a FXa inhibitor for atrial fibrillation (76.4%) and apixaban was the most common FXa inhibitor (65.2%). Hemostasis achievement was greater in the high- vs low-dose group (89.2% vs 46.7%; OR 11.2; 95% CI 2.4-52.6, P = 0.002). Thrombotic events were 8.2% and 6.7% in the high vs low-dose groups, respectively (OR 0.8; 95% CI 0.08-8.2, P = 0.87). No statistically significant differences were found in secondary outcomes.

CONCLUSION

In patients with FXa inhibitor-associated ICH, high-dose 4FPCC was associated with increased odds of hemostasis achievement. There was no difference in thrombotic events.

Strategies for the prevention and treatment of bleeding in patients treated with dabigatran: an update

INTRODUCTION

Although dabigatran is safer than vitamin K antagonists, bleeding still occurs. Bleeding is an important cause of short-term morbidity and rarely mortality and can also have long-term consequences that are often under-appreciated. After bleeding, patients often do not restart treatment or are poorly adherent, which is associated with increased thromboembolism and mortality. Consequently, we need strategies to prevent and treat bleeding in patients with atrial fibrillation treated with dabigatran.

AREAS COVERED

We review a) relevant dabigatran pharmacology, b) the burden and consequences of bleeding, c) how to identify patients at high risk of bleeding; and d) existing and novel approaches to prevent and treat bleeding in dabigatran-treated patients.

EXPERT OPINION

Concerns about the risk of bleeding associated with anticoagulant therapy and emerging evidence of increased risk of thromboembolism and mortality after bleeding highlight the need for improved approaches to prevention and treatment of bleeding. Future research priorities should focus on improving our ability to prevent bleeding by identifying modifiable risk factors and the development of safer agents. The current front runners include drugs that selectively target the contact pathway of coagulation (e.g. factor XI). Targeting upstream drivers of thrombosis (e.g. inflammation) could help to further reduce the risk of thromboembolism.

Antithrombotic and Antiplatelet Drug Toxicity

Anticoagulant and antiplatelet drugs target a specific portion of the coagulation cascade or the platelet activation and aggregation pathway. The primary toxicity associated with these agents is hemorrhage. Understanding the pharmacology of these drugs allows the treating clinician to choose the correct antidotal therapy. Reversal agents exist for some of these drugs; however, not all have proven patient-centered outcomes. The anticoagulants covered in this review are vitamin K antagonists, heparins, fondaparinux, hirudin derivatives, argatroban, oral factor Xa antagonists, and dabigatran. The antiplatelet agents reviewed are aspirin, adenosine diphosphate antagonists, dipyridamole, and glycoprotein IIb/IIIa antagonists. Additional notable toxicities are also reviewed.

Reversing Rivaroxaban Anticoagulation as Part of a Multimodal Hemostatic Intervention in a Polytrauma Animal Model

BACKGROUND

Life-threatening bleeding requires prompt reversal of the anticoagulant effects of factor Xa inhibitors. This study investigated the effectiveness of four-factor prothrombin complex concentrate in treating trauma-related hemorrhage with rivaroxaban-anticoagulation in a pig polytrauma model. This study also tested the hypothesis that the combined use of a low dose of prothrombin complex concentrate plus tranexamic acid and fibrinogen concentrate could improve its subtherapeutic effects.

METHODS

Trauma (blunt liver injury and bilateral femur fractures) was induced in 48 anesthetized male pigs after 30 min of rivaroxaban infusion (1 mg/kg). Animals in the first part of the study received prothrombin complex concentrate (12.5, 25, and 50 U/kg). In the second part, animals were treated with 12.5 U/kg prothrombin complex concentrate plus tranexamic acid or plus tranexamic acid and fibrinogen concentrate. The primary endpoint was total blood loss postinjury. The secondary endpoints (panel of coagulation parameters and thrombin generation) were monitored for 240 min posttrauma or until death.

RESULTS

The first part of the study showed that blood loss was significantly lower in the 25 U/kg prothrombin complex concentrate (1,541 ± 269 ml) and 50 U/kg prothrombin complex concentrate (1,464 ± 108 ml) compared with control (3,313 ± 634 ml), and 12.5 U/kg prothrombin complex concentrate (2,671 ± 334 ml, all P < 0.0001). In the second part of the study, blood loss was significantly less in the 12.5 U/kg prothrombin complex concentrate plus tranexamic acid and fibrinogen concentrate (1,836 ± 556 ml, P < 0.001) compared with 12.5 U/kg prothrombin complex concentrate plus tranexamic acid (2,910 ± 856 ml), and there were no early deaths in the 25 U/kg prothrombin complex concentrate, 50 U/kg prothrombin complex concentrate, and 12.5 U/kg prothrombin complex concentrate plus tranexamic acid and fibrinogen concentrate groups. Histopathologic analyses postmortem showed no adverse events.

CONCLUSIONS

Prothrombin complex concentrate effectively reduced blood loss, restored hemostasis, and balanced thrombin generation. A multimodal hemostatic approach using tranexamic acid plus fibrinogen concentrate enhanced the effect of low doses of prothrombin complex concentrate, potentially reducing the prothrombin complex concentrate doses required for effective bleeding control.

EDITOR’S PERSPECTIVE

Efficacy of prothrombin complex concentrate in the management of oral factor Xa inhibitors associated major bleed assessed by ISTH and ANNEXA-4 criteria

Direct oral anticoagulants (DOACs) are increasingly used for stroke prevention in atrial fibrillation and treatment and prevention of venous thromboembolism. They are also associated with bleeding risk. Existing literature suggests that prothrombin complex concentrate (PCC) administration may help control bleeding due to factor Xa inhibitors (FXaI). To determine the hemostatic efficacy of PCC in patients with major bleeding due to FXaI, we performed a retrospective chart review of 50 patients who presented with FXaI associated major bleeding that required urgent hemostatic management. Hemostatic assessment was performed using ISTH and ANNEXA-4 criteria. Twenty patients presented with intracranial hemorrhage (ICH), 20 had gastrointestinal bleeding, 3 had visceral bleeding, 3 had genitourinary bleeding, and 4 had miscellaneous types of bleeding. Fifty-six percent (28/50) had effective hemostasis using ISTH criteria and 84% (42/50) achieved effective hemostasis by ANNEXA-4 criteria. Hemostatic efficacy was similar by both tools for ICH (75% each). However, there was a major difference between ISTH and ANNEXA-4 hemostatic efficacy assessments for GI bleeding (45% and 95%, respectively). When comparing rivaroxaban and apixaban, there was no significant difference in effective hemostasis using either criteria, time to hemostasis, thromboembolic events, or patient mortality. Five (10%) patients had thromboembolic events within seven days of PCC administration, and the 30-day mortality rate was 14% (7/50). Our study shows similar efficacy, thromboembolic events, and mortality associated with PCC compared to andexanet alfa using ANNEXA-4 criteria, suggesting that PCC may be a viable alternative.

Low-dose versus standard-dose four-factor prothrombin complex concentrate for factor-Xa inhibitor reversal in spontaneous and traumatic intracranial hemorrhage

STUDY OBJECTIVES

Current neurocritical care guidelines recommend 50 IU/kg four-factor prothrombin complex concentrate (4PCC) for factor Xa inhibitor (FXaI) reversal in intracranial hemorrhage (ICH) based on few clinical studies conducted among non-ICH subjects. Two recent studies suggest that low-dose (25 IU/kg) 4PCC may be similar to 50 IU/kg in reversal of FXaI in ICH, and both 25 and 50 IU/kg doses are used in clinical practice for this indication. To our knowledge, no studies have directly compared 25 IU/kg versus 50 IU/kg 4PCC for FXaI reversal in ICH. The purpose of this study is to determine whether there is a difference in hemostatic efficacy between 25 IU/kg versus 50 IU/kg 4PCC for FXaI reversal in ICH.

DESIGN

This multicenter, retrospective cohort study was performed in five hospitals in central Texas from November 2013 to December 2019.

DATA SOURCE

Patients were identified with a medication use report of 4PCC and were classified in the low- or standard-dose group based on whether the 25 IU/kg or 50 IU/kg dose was received, respectively.

PATIENTS

A total of 93 patients were included (25 IU/kg, n = 62; 50 IU/kg, n = 31).

MEASUREMENTS AND MAIN RESULTS

There was no difference in hemostatic efficacy between groups (82.3% low dose vs. 83.9% standard dose, p = 0.846). No differences were identified in-hospital mortality, length of stay, thrombotic events, or the need for surgery or additional blood products between groups.

CONCLUSION

For the reversal of FXaI in ICH, a 25 IU/kg dose may be an effective alternative to 50 IU/kg 4PCC dosing.

Andexanet Alfa or Prothrombin Complex Concentrate for Factor Xa Inhibitor Reversal in Acute Major Bleeding: A Systematic Review and Meta-Analysis

OBJECTIVES

To combine evidence on andexanet alfa and prothrombin complex concentrates for factor Xa inhibitor-associated bleeding to guide clinicians on reversal strategies.

DATA SOURCES

Embase, Pubmed, Web of Science, and the Cochrane Library.

STUDY SELECTION

Observational studies and randomized clinical trials studying hemostatic effectiveness of andexanet alfa or prothrombin complex concentrate for acute reversal of factor Xa inhibitor-associated hemorrhage.

DATA EXTRACTION

Two independent reviewers extracted the data from the studies. Visualization and comparison of hemostatic effectiveness using Sarode et al or International Society of Thrombosis and Hemostasis Scientific and Standardization Committee criteria at 12 and 24 hours, (venous) thrombotic event rates, and inhospital mortality were performed by constructing Forest plots. Exploratory analysis using a logistic mixed model analysis was performed to identify factors associated with effectiveness and venous thromboembolic event.

DATA SYNTHESIS

A total of 21 studies were included (andexanet: 438 patients; prothrombin complex concentrate: 1,278 patients). The (weighted) mean effectiveness for andexanet alfa was 82% at 12 hours and 71% at 24 hours. The (weighted) mean effectiveness for prothrombin complex concentrate was 88% at 12 hours and 76% at 24 hours. The mean 30-day symptomatic venous thromboembolic event rates were 5.0% for andexanet alfa and 1.9% for prothrombin complex concentrate. The mean 30-day total thrombotic event rates for andexanet alfa and prothrombin complex concentrate were 10.7% and 3.1%, respectively. Mean inhospital mortality was 23.3% for andexanet versus 15.8% for prothrombin complex concentrate. Exploratory analysis controlling for potential confounders did not demonstrate significant differences between both reversal agents.

CONCLUSIONS

Currently, available evidence does not unequivocally support the clinical effectiveness of andexanet alfa or prothrombin complex concentrate to reverse factor Xa inhibitor-associated acute major bleeding, nor does it permit conventional meta-analysis of potential superiority. Neither reversal agent was significantly associated with increased effectiveness or a higher rate of venous thromboembolic event. These results underscore the importance of randomized controlled trials comparing the two reversal agents and may provide guidance in designing institutional guidelines.

Diagnosis and Management of Pediatric Venous Thromboembolism: New Therapies on the Horizon

ABSTRACT

The incidence of venous thromboembolism (VTE) is increasing in pediatric patients. Prompt recognition and evaluation of VTE in young patients could prevent significant morbidity or mortality. In contrast to VTE in adults, current treatment guidelines are largely based on expert opinion as limited randomized controlled trial data exist about the appropriate management in pediatric patients with traditional anticoagulants. However, recently approved direct-acting oral anticoagulants in adults are also being investigated in pediatric VTE and these data could inform future evidence-based treatment principles. Thus, healthcare providers must be well informed about the management of pediatric VTE and the data from these trials to date. This continuing medical education article will provide a summary of management of pediatric VTE with particular emphasis on emerging direct-acting oral anticoagulants.