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

The 2023 WSES guidelines on the management of trauma in elderly and frail patients

BACKGROUND

The trauma mortality rate is higher in the elderly compared with younger patients. Ageing is associated with physiological changes in multiple systems and correlated with frailty. Frailty is a risk factor for mortality in elderly trauma patients. We aim to provide evidence-based guidelines for the management of geriatric trauma patients to improve it and reduce futile procedures.

METHODS

Six working groups of expert acute care and trauma surgeons reviewed extensively the literature according to the topic and the PICO question assigned. Statements and recommendations were assessed according to the GRADE methodology and approved by a consensus of experts in the field at the 10th international congress of the WSES in 2023.

RESULTS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage, including drug history, frailty assessment, nutritional status, and early activation of trauma protocol to improve outcomes. Acute trauma pain in the elderly has to be managed in a multimodal analgesic approach, to avoid side effects of opioid use. Antibiotic prophylaxis is recommended in penetrating (abdominal, thoracic) trauma, in severely burned and in open fractures elderly patients to decrease septic complications. Antibiotics are not recommended in blunt trauma in the absence of signs of sepsis and septic shock. Venous thromboembolism prophylaxis with LMWH or UFH should be administrated as soon as possible in high and moderate-risk elderly trauma patients according to the renal function, weight of the patient and bleeding risk. A palliative care team should be involved as soon as possible to discuss the end of life in a multidisciplinary approach considering the patient's directives, family feelings and representatives' desires, and all decisions should be shared.

CONCLUSIONS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage based on assessing frailty and early activation of trauma protocol to improve outcomes. Geriatric Intensive Care Units are needed to care for elderly and frail trauma patients in a multidisciplinary approach to decrease mortality and improve outcomes.

Antidote vs. unspecific hemostatic agents for the management of direct oral anticoagulant-related bleeding in trauma

PURPOSE OF REVIEW

The advent of direct oral anticoagulants (DOACs) marks a significant milestone in anticoagulant treatment. However, DOACs can exacerbate bleeding, which is challenging for the treating clinician, especially when combined with traumatic injury.

RECENT FINDINGS

In major bleeding associated with DOACs, rapid reversal of the anticoagulant effects is crucial. Recent observational and nonrandomized interventional trials have demonstrated the effectiveness of the specific antidotes andexanet alfa and idarucizumab as well as the unspecific prothrombin complex concentrates (PCCs) to counteract the anticoagulant effects of DOACs. The European Society of Anaesthesiology and Intensive Care guideline for severe perioperative bleeding and the European trauma guideline propose divergent recommendations for the use of andexanet alfa and PCC to obtain hemostasis in Factor Xa inhibitor-related bleeding. The conflicting recommendations are due to limited evidence from clinical studies and the potential increased risk of thromboembolic complications after the administration of andexanet. Regarding dabigatran-associated major bleeding, both guidelines recommend the specific reversal agent idarucizumab as first-line therapy.

SUMMARY

Current guidelines recommend specific antidots and PCCs in DOAC-related major bleeding. Prospective randomized trials comparing specific vs. nonspecific hemostatic agents in the perioperative setting are needed to evaluate the effectiveness and safety of the hemostatic agents.

Management of DOAC-related bleeding in cancer patients: a single center-case series

Venous thromboembolism (VTE) and stroke carry significant mortality and morbidity in cancer patients. Direct oral anticoagulants (DOACs) have been demonstrated to be effective for the treatment of VTE and prevention of stroke in atrial fibrillation (AF). Bleeding rates are variable and are based on the cancer type and the patient's specific risk factors. There are approved specific antidotes for DOAC-associated bleeding. Other strategies are available for bleeding reversal, including the use of prothrombin complex concentrate (PCC). No randomized studies have compared head-to-head the efficacy and safety of reversal agents. We aim to examine the safety and effectiveness of hemostatic agents in cancer patients with DOAC-related major bleeding. A retrospective chart review study of patients at MD Anderson Cancer Center with DOAC-related major bleeding between 2014 and 2019. Bleeding severity and clinical hemostasis were described based on ISTH guidelines and the Sarode criteria, respectively. The rates of thrombotic complications and mortality at 30-day from the index bleeding event were described. We identified 23 patients with DOAC-related major bleeding; 14 patients received PCC and 9 patients received andexanet alfa. The most common sites of bleeding were the gastrointestinal tract and intracranial. Effective hemostasis and 30-day mortality were similar to reported results from other reports of outcomes of reversal agents for DOAC related-bleeding in non-cancer patients. One patient in each treatment group experienced a thrombotic event. Further larger scale studies are needed to confirm our findings in cancer patients.

Between a rock and a hard place: resumption of oral anticoagulant therapy after intracranial hemorrhage

Intracranial hemorrhage (ICH) is the most feared and lethal complication of oral anticoagulant (OAC) therapy. Resumption of OAC after ICH has long posed a challenge for clinicians, complicated by the expanding range of anticoagulant agents available in modern clinical practice, including direct OACs and, more recently, factor XI and XII inhibitors. A review of the current literature found support for resuming OAC in the majority of patients after ICH based on pooled retrospective data showing that resumption is associated with a lower risk of mortality and thromboembolism without a significantly increased risk of recurrent hemorrhage. The optimal time to resume OAC is less clear; however, the available evidence suggests that the composite risk of both recurrent hemorrhage and thromboembolism is likely minimized, somewhere between 4 and 6 weeks, after ICH in most patients. Specific considerations to guide the optimal resumption time in the individual patient include ICH location, mechanism, and anticoagulant class. Patients with mechanical heart valves and intracerebral malignancy represent high-risk groups who require more nuanced decision making. Here, we appraise the literature with the aim of providing a practical guide for clinicians while also discussing priorities for future investigation.

Site-directed mutagenesis of tissue factor pathway inhibitor-binding exosite D60A on factor VII results in a new factor VII variant with lower coagulant activity

Background

Recombinant factor (F)VIIa (rFVIIa) has been approved by the US Food and Drug Administration for the treatment of hemophilia A and B with inhibitors and congenital FVII deficiency. Moreover, the investigational uses of rFVIIa are becoming of interest since it can be used to treat various clinical bleeding conditions. However, there is evidence showing that rFVIIa is a potent procoagulant agent that potentially leads to an increased risk of thrombotic complications.

Objectives

To design a new rFVII with lower coagulant activity that could potentially be used as an alternative hemostatic agent aiming to minimize the risk of thrombogenicity.

Methods

D60A was introduced into the F7 sequence by polymerase chain reaction-based mutagenesis. Wild type (WT) and D60A were generated in human embryonic kidney 293T cells by stable transfection. FVII coagulant activities were determined by amidolytic cleavage of the FVIIa-specific substrate, 2-step FXa generation, thrombin generation (TG), and clot-based assays.

Results

WT and D60A demonstrated similar FVIIa amidolytic activity. However, D60A showed approximately 50% activity on FX activation and significantly longer lag time in the TG assay than that shown by WT. The clotting time produced by D60A spiked in FVII-deficient plasma was significantly prolonged than that of WT. Additionally, the ex vivo plasma half-lives of WT and D60A were comparable.

Conclusion

D60A demonstrated lower coagulant activities, most likely due to the weakening of FX binding, leading to impaired FX activation and delayed TG and fibrin formation. Considering that a plasma FVII level of 15% to 25% is adequate for normal hemostasis, D60A is a molecule of interest for future development of an rFVII with a lesser extent of thrombogenicity.

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.

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.

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.

CM-352 EFFICACY IN A MOUSE MODEL OF ANTICOAGULANT-ASSOCIATED INTRACRANIAL HAEMORRHAGE

BACKGROUND

Intracranial haemorrhage (ICH) is one of the major devastating complications of anticoagulation. Matrix metalloproteinases (MMPs) inhibition has been proposed as a novel pharmacological approach for ICH treatment.

OBJECTIVES

We evaluated the effects of CM-352 (MMPs-fibrinolysis inhibitor) in an experimental ICH model associated with oral anticoagulants as compared with clinically used prothrombin concentrate complex (PCC).

METHODS

ICH was induced by collagenase injection into the striatum of WT (C57BL/6J) anticoagulated mice (warfarin or rivaroxaban) and Mmp10 -/- mice. Hematoma volume and neurological deficits were measured 24h later by diaminobenzidine staining and different behavioural test. Circulating plasminogen activator inhibitor-1 (PAI-1) activity and interleukin-6 (IL-6) were measured in plasma samples and local inflammation was assessed by neutrophil infiltration. Finally, fibrinolytic effects of MMP-10 and rivaroxaban were evaluated by thromboelastometry and thrombin-activatable fibrinolysis inhibitor (TAFI) activation assays.

RESULTS

Only PCC reduced haemorrhage volume and improved functional outcome in warfarin-ICH, but both, PCC and CM-352 treatments, diminished haemorrhage volume (46%, p<0.01 and 64%, p<0.001, respectively) and ameliorated functional outcome in rivaroxaban-ICH. We further demonstrated that CM-352, but not PCC decreased neutrophil infiltration in the haemorrhage area at 24h. The effect of CM-352 could be related to MMP-10 inhibition since Mmp10-/- mice showed lower haemorrhage volume, better neurological score, reduced IL-6 levels and neutrophil infiltration, and increased PAI-1 after experimental ICH. Finally, we found that CM-352 reduced MMP-10 and rivaroxaban-related fibrinolytic effects in thromboelastometry and TAFI activation.

CONCLUSIONS

CM-352 treatment, by diminishing MMPs and rivaroxaban-associated fibrinolytic effects, might be a novel antihaemorrhagic strategy for rivaroxaban-associated ICH.

Prothrombin complex concentrates for the urgent reversal of apixaban and rivaroxaban - an Australian retrospective cohort study

BACKGROUND

Direct acting oral anticoagulants (DOACs) are now commonly prescribed medications. Urgent reversal of their anticoagulant effect is sometimes required in emergency situations. In Australia, a specific reversal agent for factor Xa (FXa)- inhibitor DOACs is not available. Instead, two non-specific haemostatic agents, activated prothrombin complex concentrate (aPCC) and 3 factor-prothrombin complex concentrate (3F-PCC), are used off-label despite a paucity of evidence for their effectiveness or safety.

METHODS

We conducted a single-centre retrospective cohort study to investigate the use of aPCC and 3F-PCC for patients on FXa-inhibitor DOACs who present with a significant bleeding event or who require urgent surgery. The primary outcome was haemostatic efficacy according to prespecified criteria. Safety outcomes included the thromboembolic event rate and all-cause mortality during the hospital admission.

RESULTS

A total of 51 patients were included in the study (36 patients who had a spontaneous bleeding even (SBE) and 15 non-bleeding patients who required urgent perioperative management). Thirty-one patients received aPCC and 20 patients received 3F-PCC. Haemostasis was adjudicated as effective in all assessable patients (n = 50; 100%). Thromboembolic events occurred in three patients who received aPCC and one patient who received 3F-PCC. All-cause mortality was 7.8% (4 patients).

CONCLUSIONS

Both aPCC and 3F-PCC are useful adjuncts for the management of patients who require urgent reversal of the anticoagulant effect of FXa-inhibitor DOACs. However, the risk of thromboembolism in this patient group requires careful consideration. Prospective, comparator studies are needed along with the development of guidelines that reflect the availability of haemostatic agents in Australia. This article is protected by copyright. All rights reserved.

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.

Direct (new) oral anticoagulants (DOACs): Drawbacks, bleeding and reversal

BACKGROUND AND OBJECTIVE

Direct (new) Oral Anticoagulants (DOACs) have emerged as a contemporary and promising option in the treatment of thromboses and VTE, while protecting the coagulation cascade against untoward bleeding events. They are used in the management and prophylaxis of Venous Thromboembolism (VTE) and other thrombotic diseases. The most prominent complication of these agents is bleeding. These agents have similar or lower rates of major intracranial hemorrhages, while they had a higher risk of major gastrointestinal bleeding when compared to warfarin. This manuscript is aimed to revise and update the literature findings to outline the side effects of DOACs in various clinical scenarios.

METHODS

A narrative review of currently published studies was performed. Online database searches were performed for clinical trials published before July 2021, on the efficacy and adverse effects attributed to the anticoagulant treatment, especially DOACs. A literature search via electronic databases was carried out, beginning with the usage of the agents in the Western Languages papers. The search terms initially included direct (new) oral anticoagulants, dabigatran, rivaroxaban, apixaban, edoxaban, idarucizumab, andexanet, prothrombin complex concentrates, and fresh frozen plasma. Papers were examined for methodological soundness before being included.

RESULTS

Severe bleeding episodes require aggressive interventions for successful management. Therefore, bleeding should be evaluated in special regard to the location and rate of hemorrhage, and total volume of blood loss. Patient's age, weight and organ dysfunctions (e.g., kidney/liver failure or chronic respiratory diseases) directly affect the clinical course of overdose.

CONCLUSION

Management recommendations for hemorrhage associated with DOAC use vary, depending on the class of the culprit agent (direct thrombin inhibitor vs. FXa inhibitor), the clinical status of the patient (mild/ moderate vs. severe/life-threatening), and capabilities of the institution. Specific reversal agents (i.e., idarucizumab and andexanet alfa) can be used if available, while prothrombin complex concentrates, fresh frozen plasma and/ or tranexamic acid can also be employed as nonspecific replacement agents in the management of DOAC-related bleeding diathesis.

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.

In vitro characterization of CT-001-a short-acting factor VIIa with enhanced prohemostatic activity

BACKGROUND

Traumatic injury and the associated acute bleeding are leading causes of death in people aged 1 to 44 years. Acute bleeding in pathological and surgical settings also represents a significant burden to the society. Yet there are no approved hemostatic drugs currently available. While clinically proven as an effective pro-coagulant, activated factor VII (FVIIa) use in acute bleeding has been hampered by unwanted thromboembolic events. Enhancing the ability of FVIIa to quickly stop a bleed and clear rapidly from circulation may yield an ideal molecule suitable for use in patients with acute bleeding.

OBJECTIVES

To address this need and the current liability of FVIIa, we produced a novel FVIIa molecule (CT-001) with enhanced potency and shortened plasma residence time by cell line engineering and FVIIa protein engineering for superior efficacy for acute bleeding and safety.

METHODS

To address safety, CT-001, a FVIIa protein with 4 desialylated N-glycans was generated to promote active recognition and clearance via the asialoglycoprotein receptor. To enhance potency, the gamma-carboxylated domain was modified with P10Q and K32E, which enhanced membrane binding.

RESULTS

Together, these changes significantly enhanced potency and clearance while retaining the ability to interact with the key hemostatic checkpoint proteins antithrombin and tissue factor pathway inhibitor.

CONCLUSIONS

These results demonstrate that a FVIIa molecule engineered to combine supra-physiological activity and shorter duration of action has the potential to overcome the current limitations of recombinant FVIIa to be a safe and effective approach to the treatment of acute bleeding.

Pathogenesis of heparin-induced thrombocytopenia

There are currently no effective substitutes for high intensity therapy with unfractionated heparin (UFH) for cardiovascular procedures based on its rapid onset of action, ease of monitoring and reversibility. The continued use of UFH in these and other settings requires vigilance for its most serious nonhemorrhagic complication, heparin induced thrombocytopenia (HIT). HIT is an immune prothrombotic disorder caused by antibodies that recognize complexes between platelet factor 4 (PF4) and polyanions such as heparin (H).The pathogenicity of anti-PF4/H antibodies is likely due to the formation of immune complexes that initiate intense procoagulant responses by vascular and hematopoietic cells that lead to the generation of platelet microparticles, monocyte and endothelial cell procoagulant activity, and neutrophil extracellular traps, among other outcomes. The development of anti-PF4/H antibodies after exposure to UFH greatly exceeds the incidence of clinical disease, but the biochemical features that distinguish pathogenic from nonpathogenic antibodies have not been identified. Diagnosis relies on pretest clinical probability, screening for anti-PF4/H antibodies and documentation of their platelet activating capacity. However, both clinical algorithms and test modalities have limited predictive values making diagnosis and management challenging. Given the unacceptable rates of recurrent thromboembolism and bleeding associated with current therapies, there is an unmet need for novel rational nonanticoagulant therapeutics based on the pathogenesis of HIT. We will review recent developments in our understanding of the pathogenesis of HIT and its implications for future approaches to diagnosis and management.

Dabigatran Reversal With Idarucizumab Preceding Thrombolysis in an Octogenarian Patient with Chronic Kidney Disease and Acute Stroke: A Case Report

BACKGROUND AND PURPOSE

Reversing the effect of dabigatran among patients with atrial fibrillation is important to normalize coagulation profile among patients who develop serious hemorrhage from any source. However, such intervention always has the potential to cause a prothrombotic state. Among patients suspected of ischemic stroke, Idarucizumab, may be administered preceding thrombolysis. This is a considerable option when given during the critical phase of revascularization.

METHODS

We report the case of an 84-year old, male, banker, known hypertensive with chronic renal disease. He has non valvular atrial fibrillation receiving Dabigatran at 75 mg twice daily and presented with symptoms of right-sided weakness, right hemisensory loss, facial asymmetry, and slurring of speech equating to National Institute of Health Stroke Scale (NIHSS) of 5. After coming into the hospital for a suspected stroke, 3 hours and 25 minutes after symptoms, complete reversal of Dabigatran with Idarucizumab was administered and intravenous thrombolysis was initiated 271 minutes post ictus. There was immediate improvement of the right upper extremity weakness and dysarthria 30 minutes post infusion. At 13 days post ictus, the patient was discharged with minimal right central facial palsy and right arm drift (NIHSS 2). Brain CT scan post revascularization did not reveal any hemorrhage and anticoagulant Apixaban 2.5 mg twice daily was started and maintained thereafter. Brain Magnetic Resonance Angiogram (MRA) showed complete recanalization of the left proximal MCA after 52 days.

CONCLUSION

Our case showed the effectiveness and safety of giving Idarucizumab followed by thrombolysis in Dabigatran-treated atrial fibrillation with ischemic stroke. Based on this case, the procedure can be performed in an elderly population with chronic kidney disease when administered close to the limit of threshold for thrombolysis.

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.

Correlation of Thromboelastography with Apparent Rivaroxaban Concentration: Has Point-of-Care Testing Improved?

BACKGROUND

Concern remains over reliable point-of-care testing to guide reversal of rivaroxaban, a commonly used factor Xa inhibitor, in high-acuity settings. Thromboelastography (TEG), a point-of-care viscoelastic assay, may have the ability to detect the anticoagulant effect of rivaroxaban. The authors ascertained the association of apparent rivaroxaban concentration with thromboelastography reaction time, i.e., time elapsed from blood sample placement in analyzer until beginning of clot formation, as measured using TEG and TEG6S instruments (Haemonetics Corporation, USA), hypothesizing that reaction time would correlate to degree of functional factor Xa impairment.

METHODS

The authors prospectively performed a diagnostic accuracy study comparing coagulation assays to apparent (i.e., indirectly assessed) rivaroxaban concentration in trauma patients with and without preinjury rivaroxaban presenting to a single center between April 2016 and July 2018. Blood samples at admission and after reversal or 24 h postadmission underwent TEG, TEG6S, thrombin generation assay, anti-factor Xa chromogenic assay, prothrombin time (PT), and ecarin chromogenic assay testing. The authors determined correlation of kaolin TEG, TEG6S, and prothrombin time to apparent rivaroxaban concentration. Receiver operating characteristic curve compared capacity to distinguish therapeutic rivaroxaban concentration (i.e., greater than or equal to 50 ng/ml) from nontherapeutic concentrations.

RESULTS

Eighty rivaroxaban patients were compared to 20 controls. Significant strong correlations existed between rivaroxaban concentration and TEG reaction time (ρ = 0.67; P < 0.001), TEG6S reaction time (ρ = 0.68; P < 0.001), and prothrombin time (ρ = 0.73; P < 0.001), however reaction time remained within the defined normal range for the assay. Rivaroxaban concentration demonstrated strong but not significant association with coagulation assays postreversal (n = 9; TEG reaction time ρ = 0.62; P = 0.101; TEG6S reaction time ρ = 0.57; P = 0.112) and small nonsignificant association for controls (TEG reaction time: ρ = -0.04; P = 0.845; TEG6S reaction time: ρ = -0.09; P = 0.667; PT-neoplastine: ρ = 0.19; P = 0.301). Rivaroxaban concentration (area under the curve, 0.91) and TEG6S reaction time (area under the curve, 0.84) best predicted therapeutic rivaroxaban concentration and exhibited similar receiver operating characteristic curves (P = 0.180).

CONCLUSIONS

Although TEG6S demonstrates significant strong correlation with rivaroxaban concentration, values within normal range limit clinical utility rendering rivaroxaban concentration the gold standard in measuring anticoagulant effect.

What we have learned about direct oral anticoagulant reversal

Bleeding is the main complication of oral anticoagulant (OAC) therapy, with major bleeds occurring in about 2% to 4% of OAC-treated patients per year. Although direct oral anticoagulants (DOACs) reduce the risk of major, fatal, and intracranial hemorrhage, major DOAC-related bleeding is associated with substantial morbidity and mortality, with case-fatality rates of 8% to 15% reported. Specific reversal agents for dabigatran (idarucizumab) and factor Xa inhibitors (andexanet) correct laboratory indices of anticoagulant effect. Clinical studies suggest that the majority of patients receiving these agents for DOAC-associated major bleeds experience clinical hemostasis. However, uncertainty remains regarding the incremental benefit of these agents and prothrombin complex concentrates over supportive measures alone, based on cohort studies that lacked control groups. Similar methodologic limitations preclude firm conclusions regarding the harms associated with use of these agents. Importantly, patients with DOAC-related major bleeding have substantial short-term risks of thrombosis and mortality, emphasizing the need for individualized patient assessment and protocolized bleed management strategies that include assessment of candidacy for safe resumption of OACs. With expanding indications and increasing prevalence of DOAC-eligible patients, bleeding complications and their management represent an ever-greater major health problem.

Consensus Report on Patient Blood Management in Cardiac Surgery by Turkish Society of Cardiovascular Surgery (TSCVS), Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care (SCTAIC)

Anemia, transfusion and bleeding independently increase the risk of complications and mortality in cardiac surgery. The main goals of patient blood management are to treat anemia, prevent bleeding, and optimize the use of blood products during the perioperative period. The benefit of this program has been confirmed in many studies and its utilization is strongly recommended by professional organizations. This consensus report has been prepared by the authors who are the task members appointed by the Turkish Society of Cardiovascular Surgery, Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care to raise the awareness of patient blood management. This report aims to summarize recommendations for all perioperative blood- conserving strategies in cardiac surgery.

Prothrombin complex concentrate for vitamin K antagonist reversal in acute bleeding settings: efficacy and safety

Introduction: Current guidelines recommend the administration of prothrombin complex concentrate in combination with vitamin K for normalization of coagulation in patients presenting with vitamin K antagonist-associated major bleeding, but until recently no adequately powered comparative trials had been conducted to support these recommendations. In this article, the authors review the evidence from studies assessing prothrombin complex concentrate treatment in these patients. Areas covered: A PubMed search (spanning January 1900 to September 2018) was conducted using the following search terms: prothrombin complex concentrate* AND (warfarin or (vitamin K antagonist*)), and papers relevant to major hemorrhagic events were identified; results from studies that used a randomized controlled trial (RCT) or a prospective design are presented here. Overall, the identified studies support the current guideline recommendations and indicate that prothrombin complex concentrates have at least similar safety profiles to other treatment options, such as fresh frozen plasma and recombinant activated factor VII. Expert opinion: It is hoped that the results from studies discussed here will inform future guideline updates; however, local clinical practice may also occasionally act as a barrier to adoption of guideline recommendations. There is an urgent need for further RCTs/prospective trials directly comparing PCC and plasma administration in acute bleeding settings.

Reversal of direct oral anticoagulants: Guidance from the Anticoagulation Forum

Two specific reversal agents for direct oral anticoagulants (DOACs) have been approved in the United States: idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. Non-specific prohemostatic agents such as prothrombin complex concentrate (PCC) and activated PCC have also been used for DOAC reversal. The goal of this document is to provide comprehensive guidance from the Anticoagulation Forum, a North American organization of anticoagulation providers, regarding use of DOAC reversal agents. We discuss indications for reversal, provide guidance on how the individual reversal agents should be administered, and offer suggestions for stewardship at the health system level.

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.

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.