Reversal agents for non-vitamin K antagonist oral anticoagulants

Reversal of direct oral anticoagulants: guidance from the SSC of the ISTH

The currently approved direct oral anticoagulants (DOACs) are increasingly used in clinical practice. Although serious bleeding risks are lower with DOACs than with vitamin K antagonists, bleeding remains the most frequent side effect. Andexanet alfa and idarucizumab are the currently approved specific reversal agents for oral factor (F)Xa inhibitors and dabigatran, respectively. Our prior guidance document was published in 2016, but with more information available on the utility and increased use of these reversal agents and other bleeding management strategies, we have updated this International Society on Thrombosis and Haemostasis guidance document on DOAC reversal. In this narrative review, we compare the mechanism of action of specific and nonspecific reversal agents, review the clinical data supporting their use, and provide guidance on when reversal is indicated. In addition, we briefly discuss the reversal of oral FXIa inhibitors, a new class of DOACs currently under clinical development.

Impact of elevated direct factor Xa inhibitor plasma levels on perioperative blood loss in patients undergoing urgent surgery

INTRODUCTION

Data on the perioperative bleeding risk associated with elevated plasma levels of direct factor Xa inhibitors (FXa inhibitors) are limited. This study examines perioperative red blood cell (RBC) loss in patients undergoing urgent surgery with a residual FXa inhibitor level exceeding 100 mcg/L and without preoperative FXa inhibitor reversal.

METHODS

This retrospective analysis includes data from 32 patients who underwent urgent noncardiac surgery between 2018 and 2022. This study aims to analyze perioperative RBC loss in patients undergoing urgent surgery with a residual FXa inhibitor level exceeding 100 mcg/L and without preoperative FXa inhibitor antidote-based reversal or unspecific treatment with 4-factor prothrombin complex concentrate (PCC). All patients were managed using a watch-and-wait strategy.

RESULTS

The last determination of FXa inhibitor plasma concentration prior to surgery showed a median of 245 mcg/L (IQR 144-345), with a median time interval of 3.8 h (IQR 2.4-7.2) before incision. Median RBC loss during surgery was 49 mL (IQR 0-253), 189 mL (IQR 104-217) until POD1 and 254 mL (IQR 58-265) until POD3. Only one patient required intraoperative treatment with 4-factor-PCC and none required reversal with andexanet alfa. Linear regression models found no significant influence of FXa inhibitor plasma levels on intraoperative RBC loss. Rivaroxaban was associated with higher RBC loss until postoperative Day 1 compared with apixaban. No thromboembolic events were observed.

CONCLUSION

Despite markedly elevated plasma concentrations of residual direct FXa inhibitors, perioperative RBC loss was limited in patients undergoing urgent noncardiac surgery. The intraoperative watch-and-wait strategy with selective intraoperative FXa inhibitor reversal or treatment only when required appears to be an appropriate approach.

Perioperative Management of Patients Taking Direct Oral Anticoagulants: A Review

Importance

Direct oral anticoagulants (DOACs), comprising apixaban, rivaroxaban, edoxaban, and dabigatran, are commonly used medications to treat patients with atrial fibrillation and venous thromboembolism. Decisions about how to manage DOACs in patients undergoing a surgical or nonsurgical procedure are important to decrease the risks of bleeding and thromboembolism.

Observations

For elective surgical or nonsurgical procedures, a standardized approach to perioperative DOAC management involves classifying the risk of procedure-related bleeding as minimal (eg, minor dental or skin procedures), low to moderate (eg, cholecystectomy, inguinal hernia repair), or high risk (eg, major cancer or joint replacement procedures). For patients undergoing minimal bleeding risk procedures, DOACs may be continued, or if there is concern about excessive bleeding, DOACs may be discontinued on the day of the procedure. Patients undergoing a low to moderate bleeding risk procedure should typically discontinue DOACs 1 day before the operation and restart DOACs 1 day after. Patients undergoing a high bleeding risk procedure should stop DOACs 2 days prior to the operation and restart DOACs 2 days after. With this perioperative DOAC management strategy, rates of thromboembolism (0.2%-0.4%) and major bleeding (1%-2%) are low and delays or cancellations of surgical and nonsurgical procedures are infrequent. Patients taking DOACs who need emergent (<6 hours after presentation) or urgent surgical procedures (6-24 hours after presentation) experience bleeding rates up to 23% and thromboembolism as high as 11%. Laboratory testing to measure preoperative DOAC levels may be useful to determine whether patients should receive a DOAC reversal agent (eg, prothrombin complex concentrates, idarucizumab, or andexanet-α) prior to an emergent or urgent procedure.

Conclusions and Relevance

When patients who are taking a DOAC require an elective surgical or nonsurgical procedure, standardized management protocols can be applied that do not require testing DOAC levels or heparin bridging. When patients taking a DOAC require an emergent, urgent, or semiurgent surgical procedure, anticoagulant reversal agents may be appropriate when DOAC levels are elevated or not available.

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.

How I treat pediatric venous thromboembolism in the DOAC era

ABSTRACT

The direct oral anticoagulants (DOACs) rivaroxaban and dabigatran are newly licensed for the treatment and prevention of venous thromboembolism (VTE) in children and mark a renaissance in pediatric anticoagulation management. They provide a convenient option over standard-of-care anticoagulants (heparins, fondaparinux, and vitamin K antagonists) because of their oral route of administration, child-friendly formulations, and significant reduction in monitoring. However, limitations related to therapeutic monitoring when needed and the lack of approved reversal agents for DOACs in children raise some safety concerns. There is accumulating experience of safety and efficacy of DOACs in adults for a broad scope of indications; however, the cumulative experience of using DOACs in pediatrics, specifically for those with coexisting chronic illnesses, is sparse. Consequently, clinicians must often rely on their experience for treating VTE and extrapolate from data in adults while using DOACs in children. In this article, the authors share their experience of managing 4 scenarios that hematologists are likely to encounter in their day-to-day practice. Topics addressed include (1) appropriateness of indication; (2) use for special populations of children; (3) considerations for laboratory monitoring; (4) transition between anticoagulants; (5) major drug interactions; (6) perioperative management; and (7) anticoagulation reversal.

Dose-Related Effectiveness of Andexanet Alfa for Reversal of Apixaban Anticoagulation in a Porcine Polytrauma Model

BACKGROUND

 Andexanet alfa (andexanet) is a reversal agent for use in patients with life-threatening or uncontrolled bleeding treated with oral factor Xa (FXa) inhibitors. There are limited data on the dose-response relationship of andexanet and FXa inhibitor-related bleeding.

OBJECTIVE

 The aim of this study was to assess the dose-related effectiveness of andexanet in reducing blood loss, improving survival, and reversing apixaban anticoagulation in a porcine polytrauma model.

METHODS

 Apixaban was given orally to 40 male pigs for 3 days at a dose of 20 mg/d. On day 3, following bilateral femur fractures and blunt liver injury, animals (n = 8/group) received andexanet (250-mg bolus, 250-mg bolus + 300-mg 2-hour infusion, 500-mg bolus, or 500-mg bolus + 600-mg 2-hour infusion) or vehicle (control). Total blood loss was the primary endpoint. Coagulation parameters were assessed for 300 minutes or until death. Data were analyzed with a mixed-model analysis of variance.

RESULTS

 Administration of 250-mg bolus + 300-mg infusion, andexanet 500-mg bolus, and 500-mg bolus + 600-mg infusion significantly decreased total blood loss by 37, 58, and 61%, respectively (all p < 0.0001), with 100% survival. Andexanet 250-mg bolus was ineffective in reducing total blood loss (6%) and mortality (63% survival) versus controls. Andexanet 500-mg bolus ± infusion neutralized anti-FXa activity to less than 50 ng/mL. Andexanet neutralization of thrombin generation and thromboelastometry parameters was dose and infusion time dependent.

CONCLUSION

 In a porcine polytrauma model with major bleeding on apixaban, andexanet dose dependently decreased anti-FXa activity. Lower anti-FXa levels (<50 ng/mL) with andexanet 500-mg bolus ± infusion were correlated with 60% less blood loss and 100% survival versus controls.

Effect of antiplatelet and anticoagulant medication use on injury severity and mortality in patients with traumatic brain injury treated in the intensive care unit

BACKGROUND

Antiplatelet and anticoagulant medication are increasingly common and can increase the risks of morbidity and mortality in traumatic brain injury (TBI) patients. Our study aimed to quantify the association of antiplatelet or anticoagulant use in intensive care unit (ICU)-treated TBI patients with 1-year mortality and head CT findings.

METHOD

We conducted a retrospective, multicenter observational study using the Finnish Intensive Care Consortium database. We included adult TBI patients admitted to four university hospital ICUs during 2003-2013. The patients were followed up until the end of 2016. The national drug reimbursement database provided information on prescribed medication for our study. We used multivariable logistic regression models to assess the association between TBI severity, prescribed antiplatelet and anticoagulant medication, and their association with 1-year mortality.

RESULTS

Of 3031 patients, 128 (4%) had antiplatelet and 342 (11%) anticoagulant medication before their TBI. Clopidogrel (2%) and warfarin (9%) were the most common antiplatelets and anticoagulants. Three patients had direct oral anticoagulant (DOAC) medication. The median age was higher among antiplatelet/anticoagulant users than in non-users (70 years vs. 52 years, p < 0.001), and their head CT findings were more severe (median Helsinki CT score 3 vs. 2, p < 0.05). In multivariable analysis, antiplatelets (OR 1.62, 95% CI 1.02-2.58) and anticoagulants (OR 1.43, 95% CI 1.06-1.94) were independently associated with higher odds of 1-year mortality. In a sensitivity analysis including only patients over 70, antiplatelets (OR 2.28, 95% CI 1.16-4.22) and anticoagulants (1.50, 95% CI 0.97-2.32) were associated with an increased risk of 1-year mortality.

CONCLUSIONS

Both antiplatelet and anticoagulant use before TBI were risk factors in our study for 1-year mortality. Antiplatelet and anticoagulation medication users had a higher radiological intracranial injury burden than non-users defined by the Helsinki CT score. Further investigation on the effect of DOACs on mortality should be done in ICU-treated TBI patients.

Direct oral anticoagulants and their antagonists in perioperative practice

PURPOSE OF REVIEW

Review management strategies for patients receiving nonvitamin K direct-acting oral anticoagulants (DOACs).

RECENT FINDINGS

Updated clinical trials and guidelines continue to further define optimal management for patients on DOACs requiring emergency surgery or procedural interventions. In addition, specific bleeding management strategies that include either specific or nonspecific antagonists are becoming available.

SUMMARY

Most currently used DOACs are factor Xa inhibitors and should be stopped for 24-48 h for elective surgical procedures in patients at risk for bleeding and potentially longer for dabigatran, depending on renal function. Idarucizumab, a specific dabigatran reversal agent, has been studied in surgical patients and is currently approved for use. For Xa inhibitors apixaban and rivaroxaban, although andexanet alfa is approved for medical bleeds, it is not approved for surgical patients, has a short duration of effect, and costs $12 500 per gram. When managing DOAC-treated patients requiring emergency surgery, when stopping the DOAC and delaying surgery is not feasible, standard approaches should include hemostatic, hemodynamic, and transfusional support. Due to higher risk associated with therapeutic agents used to manage DOAC-related bleeding, increasing data supports the potential off-label use of prothrombin complex concentrate (PCC).

Case Report: Extended Duration Andexanet Alfa Infusion in a Surgical Trauma Patient

Background: Andexanet alfa (andexanet) is the only FDA-approved medication for reversal of apixaban and rivaroxaban anticoagulation for life-threatening or uncontrolled bleeding. Infusion modifications may be required in surgical patients undergoing prolonged operative intervention but have not previously been described. Case Report: A 78-year-old woman on rivaroxaban for atrial fibrillation was admitted to the trauma service for a mechanical fall, sustaining a T4 burst fracture with severe canal stenosis and spinal cord edema resulting in loss of strength and sensation in her legs. Clinically relevant rivaroxaban activity was verified with an elevated low molecular weight heparin anti-factor Xa assay, and laboratory confirmed coagulopathy was demonstrated by a prolonged prothrombin time, thromboelastography (TEG) R-time, and activated clotting time (ACT). The patient required urgent surgical intervention for spinal fixation. Given the expected prolonged duration of the procedure, standard dose andexanet was initiated with a prolonged infusion at half the standard rate during the operation. The procedure was successful and intraoperative TEGs demonstrated normalization of R-time and ACT throughout the procedure. The patient did not experience any complications postoperatively and successfully discharged to inpatient rehabilitation. Conclusion: Modifications to the andexanet infusion may be required in surgical patients requiring rivaroxaban reversal for a prolonged procedure. Further data are needed to determine the optimal approach to infusion modification.

Direct oral anticoagulants or vitamin K antagonists in emergencies: comparison of management in an observational study

Background

Restoring hemostasis in patients on oral anticoagulants presenting with major hemorrhage (MH) or before surgical intervention has changed, with the replacement of vitamin K antagonist (VKA) with direct oral anticoagulants (DOACs).

Objectives

To observe the difference in urgent hemostatic management between patients on VKA and those on DOACs.

Methods

A multicenter observational study evaluated the variation in laboratory testing, hemostatic management, mortality, and hospital length of stay (LOS) in patients on VKA or DOACs presenting with MH or urgent hemostatic restoration.

Results

Of the 1194 patients analyzed, 783 had MH (61% VKA) and 411 required urgent hemostatic restoration before surgery (56% VKA). Compared to the international normalized ratio (97.6%), plasma DOAC levels were measured less frequently (<45%), and the time taken from admission for the coagulation sample to reach the laboratory varied widely (median, 52.3 minutes; IQR, 24.8-206.7). No significant plasma DOAC level (<50 ng/mL) was found in up to 19% of patients. There was a poor relationship between plasma DOAC level and the usage of a hemostatic agent. When compared with patients receiving VKA (96.5%) or dabigatran (93.7%), fewer patients prescribed a factor Xa inhibitor (75.5%) received a prohemostatic reversal agent. The overall 30-day mortality for MH (mean: 17.8%) and length of stay (LOS) (median: 8.7 days) was similar between VKA and DOAC patients.

Conclusion

In DOAC patients, when compared to those receiving VKA, plasma DOAC levels were measured less frequently than the international normalized ratio and had a poor relationship with administering a hemostatic reversal agent. In addition, following MH, mortality and LOS were similar between VKA and DOAC patients.

What's fishy about protamine? Clinical use, adverse reactions, and potential alternatives

Protamine, a highly basic protein isolated from salmon sperm, is the only clinically available agent to reverse the anticoagulation of unfractionated heparin. Following intravenous administration, protamine binds to heparin in a nonspecific electrostatic interaction to reverse its anticoagulant effects. In clinical use, protamine is routinely administered to reverse high-dose heparin anticoagulation in cardiovascular procedures, including cardiac surgery with cardiopulmonary bypass. Despite the lack of supportive evidence regarding protamine's effectiveness to reverse low-molecular-weight heparin, it is recommended in guidelines with low-quality evidence. Different dosing strategies have been reported for reversing heparin in cardiac surgical patients based on empiric dosing, pharmacokinetics, or point-of-care measurements of heparin levels. Protamine administration is associated with a spectrum of adverse reactions that range from vasodilation to life-threatening cardiopulmonary dysfunction and shock. The life-threatening responses appear to be hypersensitivity reactions due to immunoglobulin E and/or immunoglobulin G antibodies. However, protamine and heparin-protamine complexes can activate complement inflammatory pathways and inhibit other coagulation factors. Although alternative agents for reversing heparin are not currently available for clinical use, additional research continues evaluating novel therapeutic approaches.

Oral Anticoagulation in Patients With Advanced Chronic Kidney Disease and Atrial Fibrillation: Beyond Anticoagulation

The optimal approach to prevent stroke and systemic embolism in patients with advanced chronic kidney disease (CKD) and atrial fibrillation remains unresolved. We conducted a narrative review to explore areas of uncertainty and opportunities for future research. First, the relationship between atrial fibrillation and stroke is more complex in patients with advanced CKD than in the general population. The currently employed risk stratification tools do not adequately discriminate between patients deriving a net benefit and those suffering a net harm from oral anticoagulation. Anticoagulation initiation should probably be more restrictive than is currently advocated by official guidelines. Recent evidence reveals that the superior benefit-risk profile of non-vitamin K antagonist oral anticoagulants (NOACs) vs vitamin K antagonists (VKAs) observed in the general population and in moderate CKD can be extended to advanced CKD. The NOACs yield better protection against stroke, cause less major bleeding, are associated with less acute kidney injury and a slower decline of CKD, and are associated with a lower incidence of cardiovascular events than VKAs. The VKAs may be harmful in CKD patients, in particular in patients with a high bleeding risk and labile international normalized ratio. The better safety and efficacy of NOACs as opposed to VKAs may be particularly evident in advanced CKD as a result of better on-target anticoagulation with NOACs, harmful off-target vascular effects of VKAs, and beneficial off-target vascular effects of NOACs. The intrinsic vasculoprotective effects of NOACs are supported by animal experimental evidence as well as by findings of large clinical trials and may result in use of NOACs beyond their anticoagulant properties.

Direct Oral Anticoagulants: An Updated Systematic Review of Their Clinical Pharmacology and Clinical Effectiveness and Safety in Patients With Nonvalvular Atrial Fibrillation

Direct oral anticoagulants have been an increasingly used class of drugs in the setting of nonvalvular atrial fibrillation, defying vitamin K antagonists' monopoly when it comes to anticoagulation due to its several limitations. Direct oral anticoagulants (DOACs) have entered the market as a noninferior and safer option in comparison with vitamin K antagonists, as their respective phase III clinical trials proved. The aim of this article was to update and summarize data on their clinical pharmacology and to review real-world data to know their comparative effectiveness and safety. We performed a systematic review using PubMed, Google Scholar, Embase, and Web of Science as search engines. Regarding pharmacodynamics, there were no substantial changes reported from their original profile. There were many advances in the knowledge about clinical pharmacokinetics of DOACs that have had a direct impact on their clinical use, mainly related to drug-drug interactions. In a real-world setting, DOACs have shown to be noninferior in preventing thromboembolic events compared to vitamin K antagonists. In regards to safety, DOACs have shown a lower bleeding risk relative to warfarin. Comparison between DOACs has demonstrated rivaroxaban to have the highest bleeding risk. Overall, the evidence gathered showed few changes from the original data presented in phase III clinical trials, concluding that their real-world use coincides greatly with them.

Research Opportunities in Stroke Prevention for Atrial Fibrillation: A Report From a National Heart, Lung, and Blood Institute Virtual Workshop

Atrial fibrillation (AF) is one of the strongest risk factors for ischemic stroke, which is a leading cause of disability and death. Given the aging population, increasing prevalence of AF risk factors, and improved survival in those with cardiovascular disease, the number of individuals affected by AF will continue increasing over time. While multiple proven stroke prevention therapies exist, important questions remain about the optimal approach to stroke prevention at the population and individual patient levels. Our report summarizes the National Heart, Lung, and Blood Institute virtual workshop focused on identifying key research opportunities related to stroke prevention in AF. The workshop reviewed major knowledge gaps and identified targeted research opportunities to advance stroke prevention in AF in the following areas: (1) improving risk stratification tools for stroke and intracranial hemorrhage; (2) addressing challenges with oral anticoagulants; and (3) delineating the optimal roles of percutaneous left atrial appendage occlusion and surgical left atrial appendage closure/excision. This report aims to promote innovative, impactful research that will lead to more personalized, effective use of stroke prevention strategies in people with AF.

A new model to predict the risk of major gastrointestinal bleeding in patients on direct oral anticoagulants (dabigatran and rivaroxaban)

AIMS

The aim of this study was to identify factors associated with gastrointestinal bleeding (GIB) in patients on direct oral anticoagulants (DOACs) and develop a risk score that would provide an effective tool for the clinical assessment of GIB.

METHODS

This was a multicentre retrospective analysis of clinical and follow-up data of patients treated with DOACs. The score was developed through logistic regression. The performance of score was evaluated using the area under the receiver operating characteristic curve (AUC), sensitivity, specificity and Hosmer-Lemeshow test.

RESULTS

The 11 903 patients had a mean age of 65.1 years. In multivariate analysis, age ≥65 years, alcohol use, history of peptic ulcer, history of major bleeding, abnormal liver function or renal function, cancer, platelet count <100 × 10⁹ /L, anaemia, and concurrent antiplatelet agent or non-steroidal anti-inflammatory drug treatment were independent risk factors for GIB, and concurrent treatment with gastrointestinal protective agents were a protective factor. The Alfalfa-DOAC-GIB score was constructed using these 12 factors. The AUC of the Alfalfa-DOAC-GIB score was 0.77 (95% CI 0.74-0.81), which was higher than that of the HAS-BLED score (0.69; 95% CI 0.65-0.72) and the New score (0.65; 95% CI 0.61-0.68).

CONCLUSIONS

Based on 12 factors, we developed a gastrointestinal bleeding risk score. The newly developed Alfalfa-DOAC-GIB score has better predictive value than the HAS-BLED score and the New score, and might be an effective tool to help reduce the occurrence of GIB in patients using DOACs.

Perioperative Management of Antithrombotic Therapy: An American College of Chest Physicians Clinical Practice Guideline

BACKGROUND

The American College of Chest Physicians Clinical Practice Guideline on the Perioperative Management of Antithrombotic Therapy addresses 43 Patients-Interventions-Comparators-Outcomes (PICO) questions related to the perioperative management of patients who are receiving long-term oral anticoagulant or antiplatelet therapy and require an elective surgery/procedure. This guideline is separated into four broad categories, encompassing the management of patients who are receiving: (1) a vitamin K antagonist (VKA), mainly warfarin; (2) if receiving a VKA, the use of perioperative heparin bridging, typically with a low-molecular-weight heparin; (3) a direct oral anticoagulant (DOAC); and (4) an antiplatelet drug.

METHODS

Strong or conditional practice recommendations are generated based on high, moderate, low, and very low certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology for clinical practice guidelines.

RESULTS

A multidisciplinary panel generated 44 guideline recommendations for the perioperative management of VKAs, heparin bridging, DOACs, and antiplatelet drugs, of which two are strong recommendations: (1) against the use of heparin bridging in patients with atrial fibrillation; and (2) continuation of VKA therapy in patients having a pacemaker or internal cardiac defibrillator implantation. There are separate recommendations on the perioperative management of patients who are undergoing minor procedures, comprising dental, dermatologic, ophthalmologic, pacemaker/internal cardiac defibrillator implantation, and GI (endoscopic) procedures.

CONCLUSIONS

Substantial new evidence has emerged since the 2012 iteration of these guidelines, especially to inform best practices for the perioperative management of patients who are receiving a VKA and may require heparin bridging, for the perioperative management of patients who are receiving a DOAC, and for patients who are receiving one or more antiplatelet drugs. Despite this new knowledge, uncertainty remains as to best practices for the majority of perioperative management questions.

In Vivo Anticoagulant and Antithrombic Activity of Depolymerized Glycosaminoglycan from Apostichopus japonicus and Dynamic Effect-Exposure Relationship in Rat Plasma

Glycosaminoglycan from Apostichopus japonicus (AHG) and its depolymerized fragments (DAHGs) are anticoagulant fucosylated chondroitin sulfate. The aim of this study was to further evaluate the anticoagulant and antithrombic activity of AHG and DAHGs, as well as reveal the dynamic relationship between exposure and effect in vivo. The results demonstrated that AHG100 (Mw~100 kDa), DAHG50 (Mw~50 kDa), and DAHG10 (Mw~10 kDa) exhibited potent anticoagulant activity by inhibiting intrinsic factor Xase complex (FXase) as well as antithrombin-dependent factor IIa (FIIa) and factor Xa (FXa). These glycosaminoglycans markedly prevented thrombosis formation and thrombin-induced platelet aggregation in a dose- and molecular weight-dependent manner in vitro and in vivo. The further bleeding time measurement indicated that DAHG10 exhibited obviously lower hemorrhage risks than native AHG100. Following oral administration, DAHG10 could be absorbed into blood, further dose-dependently prolonging activated partial thromboplastin time (APTT) and thrombin time (TT) as well as inhibiting FXa and FIIa partially through FXase. Anticoagulant activity was positively associated with plasma concentration following oral administration of DAHG10. Our study proposed a new point of view to understand the correlation between effects and exposure of fucosylated chondroitin sulfate as an effective and safe oral antithrombotic agent.

Reversal of apixaban and rivaroxaban with andexanet alfa prior to invasive or surgical procedures

BACKGROUND

Outcomes following andexanet alfa reversal of factor Xa inhibitors in patients requiring urgent or emergent invasive procedures are lacking. This study aimed to describe efficacy and safety outcomes following andexanet alfa administration within 24 h of an invasive procedure.

METHODS

This single-center, observational, retrospective study included patients who received andexanet alfa within 24 h of an invasive or surgical procedure. The primary outcome was hemostatic efficacy graded as excellent, good, or poor using similar definitions to the ANNEXA-4 criteria. Secondary outcomes included hospital discharge disposition, intensive care unit (ICU) and hospital length of stay, 30-day mortality, 30-day thromboischemic event rates, and serum coagulation assay changes pre- and postreversal.

RESULTS

Forty-four patients met inclusion criteria; of these, 27 (62.8%) received apixaban and 16 (37.2%) were treated with rivaroxaban prior to admission. The indications for reversal were categorized as intracranial (n = 20 [45.5%]) or extracranial (n = 24 [54.5%]) sites. Majority of patients required emergent operative procedures (18 [40.9%]), followed by invasive device placement (10 [22.7%]) or arterial embolization (9 [20.5%]). Thirty-eight (86.4%) patients were able to be adequately graded for hemostatic efficacy. Overall, 30 (78.9%) patients achieved excellent or good hemostasis within 24 h after periprocedural administration of andexanet alfa (19 [82.6%] apixaban vs. 11 [78.6%] rivaroxaban; 12 [80.0%] intracranial events vs. 18 [78.3%] extracranial events). Discharge disposition was most often to a short- or long-term care facilities (27 [61.4%]). Thirty-day mortality and thromboischemic complications occurred in 15 (34.1%) and 12 (27.3%) patients, respectively. Prothrombin time and antifactor Xa assay results were significantly decreased after andexanet alfa administration (p < 0.05) while thromboelastogram assay values (reaction time, kinetic time, and activated clotting time) showed nonsignificant changes pre- versus postreversal.

CONCLUSION

Andexanet alfa may be used for urgent or emergent reversal of apixaban and rivaroxaban peri-procedurally with promising hemostatic outcomes. Further prospective, comparative clinical research is warranted.

Bleeding disorders in implant dentistry: a narrative review and a treatment guide

Purpose

Considering a high prevalence of congenital and especially acquired bleeding disorders, their heterogeneity and the multitude of possible treatments strategies, a review of the scientific data on this topic is needed to implement a treatment guide for healthcare professionals.

Methods

A selective literature review was performed via PubMed for articles describing oral surgery / dental implant procedures in patients with congenital and acquired bleeding disorders. Out of the existing literature, potential treatment algorithms were extrapolated.

Results

In order to assess the susceptibility to bleeding, risk stratification can be used for both congenital and acquired coagulation disorders. This risk stratification, together with an appropriate therapeutic pathway, allows for an adequate and individualized therapy for each patient. A central point is the close interdisciplinary cooperation with specialists. In addition to the discontinuation or replacement of existing treatment modalities, local hemostyptic measures are of primary importance. If local measures are not sufficient, systemically administered substances such as desmopressin and blood products have to be used.

Conclusions

Despite the limited evidence, a treatment guide could be developed by means of this narrative review to improve safety for patients and practitioners. Prospective randomized controlled trials are needed to allow the implementation of official evidence-based guidelines.

Dynamic Combinatorial Optimization of In Vitro and In Vivo Heparin Antidotes

Heparin-like macromolecules are widely used in clinics as anticoagulant, antiviral, and anticancer drugs. However, the search of heparin antidotes based on small synthetic molecules to control blood coagulation still remains a challenging task due to the physicochemical properties of this anionic polysaccharide. Here, we use a dynamic combinatorial chemistry approach to optimize heparin binders with submicromolar affinity. The recognition of heparin by the most amplified members of the dynamic library has been studied with different experimental (SPR, fluorescence, NMR) and theoretical approaches, rendering a detailed interaction model. The enzymatic assays with selected library members confirm the correlation between the dynamic covalent screening and the in vitro heparin inhibition. Moreover, both ex vivo and in vivo blood coagulation assays with mice show that the optimized molecules are potent antidotes with potential use as heparin reversal drugs. Overall, these results underscore the power of dynamic combinatorial chemistry targeting complex and elusive biopolymers.

Non-Vitamin K Oral Anticoagulant After Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Objective: We aimed to compare non-vitamin K oral anticoagulants (NOACs) with a traditional antithrombotic such as vitamin K antagonist (VKA) and antiplatelet agents in patients after transcatheter aortic valve replacement (TAVR). Methods: We conducted a search in PubMed, EMBASE, and the Cochrane Library until November 2021 for studies involving comparisons of any type of NOACs, including dabigatran, apixaban, rivaroxaban, and edoxaban, with VKA or antiplatelet agents after TAVR. A comparison of NOACs versus VKA was performed in patients with an indication for oral anticoagulation. In addition, we compared NOACs versus antiplatelet in patients without such indication. We calculated the hazard ratios with 95% confidence intervals (CIs) to determine long-term outcomes. The primary outcome was a combined endpoint consisting of all-cause mortality, stroke, major bleeding, or any related clinical adverse events. Secondary outcomes were all-cause mortality, major bleeding, and stroke, respectively. Results: A total of 10 studies including 10,563 patients after TAVR were included in this meta-analysis. There were no significant differences in any of the long-term outcomes between the NOAC and VKA groups. Although there were no significant differences in the combined endpoint, major bleeding, or stroke, a significant difference was observed in the all-cause mortality (HR 1.74, 95% CI 1.25-2.43, p = 0.001) between the NOAC and antiplatelet groups. Conclusion: For patients with an indication for oral anticoagulation after TAVR, NOACs seem to be associated with noninferior outcomes compared with VKA therapy. However, for patients without an indication for oral anticoagulation, NOACs appear to be associated with a higher risk of all-cause death as compared with antiplatelet treatment. Systematic Review Registration: https://clinicaltrials.gov/, identifier CRD42020155122.

Optimizing adherence and persistence to non-vitamin K antagonist oral anticoagulant therapy in atrial fibrillation

Atrial fibrillation (AF) is associated with an increased risk of stroke, which can be prevented by the use of oral anticoagulation. Although non-vitamin K antagonist oral anticoagulants (NOACs) have become the first choice for stroke prevention in the majority of patients with non-valvular AF, adherence and persistence to these medications remain suboptimal, which may translate into poor health outcomes and increased healthcare costs. Factors influencing adherence and persistence have been suggested to be patient-related, physician-related, and healthcare system-related. In this review, we discuss factors influencing patient adherence and persistence to NOACs and possible problem solving strategies, especially involving an integrated care management, aiming for the improvement in patient outcomes and treatment satisfaction.

Effects of direct oral anticoagulants dabigatran and rivaroxaban on the blood coagulation function in rabbits

The aim of this study was to explore the effects of dabigatran and rivaroxaban on the activities of various coagulation factors. To achieve that, 60 rabbits were randomly divided into experimental groups that received different doses of dabigatran or rivaroxaban. The effects of dabigatran and rivaroxaban on the activities of FII, FV, FVIII, FX, and activated protein C (APC) were analyzed. In the dabigatran groups, activated partial thromboplastin time and thromboplastin time (TT) were prolonged after drug administration, and the activities of FII, FV, FVIII, and FX were inhibited as the drug concentration increased. Low doses of dabigatran inhibited APC activity. In the rivaroxaban groups, APTT and TT were not significantly prolonged after drug administration. In contrast, the high-dose rivaroxaban group exhibited prolonged PT, and the degree of inhibition of the activities of FII, FV, FVIII, and FX increased as the drug concentration increased. Rivaroxaban had no significant effect on APC activity regardless of dosage. As the drug concentration increased, both NOACs had more significant inhibitory effects on the activities of FII, FV, FVIII, and FX. Low concentrations of dabigatran generated an inhibitory effect on APC activity, while high concentrations of dabigatran had no significant effect. Rivaroxaban had no significant effect on APC activity.

Perioperative management of antithrombotic therapy: a case-based narrative review

The periprocedural management of patients who are receiving vitamin K antagonists, direct oral anticoagulants and antiplatelet therapy is a common and challenging clinical scenario as the decision to interrupt or continue these medications is anchored on patient and procedure-related risks for bleeding and thrombosis. Adding to the complexity of clinical management is the fact that anticoagulants have varied pharmacokinetic and pharmacodynamic properties and indications for clinical use. In many minimal-bleed-risk procedures, anticoagulants can be safely continued, without interruption, whereas in cases where anticoagulants cannot be safely continued, the timing of interruption and resumption, as well as the need for heparin bridging requires consideration. Perioperative antithrombotic management scenarios occur most often in patients with atrial fibrillation, mechanical heart valves, coronary stents, and cerebrovascular disease as such patients are likely to be prescribed anticoagulant and/or antiplatelet therapy. The objective of this case-based narrative review is to provide a practical evidence-based approach to the perioperative management of patients on anticoagulation and antiplatelet therapy. Four clinical scenarios will be provided: (1) managing patients in whom anticoagulants can be continued; (2) perioperative management of direct oral anticoagulants; (3) management of patients on dual antiplatelet therapy; and (4) anticoagulant management for emergency or urgent surgery.

Comparison of the Safety and Efficacy of Direct Oral Anticoagulants and Warfarin in Atrial Fibrillation or Venous Thromboembolism in Patients with Renal Impairment: Systematic Review, Meta-Analysis and Network Meta-Analysis

BACKGROUND

Due to the high risk of ischemic and arterial or venous bleeding events in atrial fibrillation (AF) or venous thromboembolism (VTE) patients with renal impairment (RI), selection of appropriate anticoagulant regimen is important. Therefore, we systematically reviewed and compared the safety and effects of oral anticoagulants in AF and VTE patients with RI.

METHODS

Eligible articles were identified through a literature search in PubMed, Embase, ClinicalTrials.gov, and the Cochrane Library for studies published between January 2008 and November 2020. Network meta-analysis was conducted with STATA 14.0 to analyze the effects and safety of each drug with regard to different levels of renal function.

RESULTS

15 studies including 82,931 patients (76,957 with AF and 5974 with VTE) were analyzed. Compared with those of warfarin, the risk ratios of effect and safety outcomes of apixaban were 0.70 (95% confidence interval [CI] 0.60-0.82) and 0.56 (95% CI 0.42-0.76) in AF patients and 0.33 (95% CI 0.19-0.59) and 0.95 (95% CI 0.68-1.34) in VTE patients. Apixaban had the first or second highest probability of being ranked first with respect to surface under the cumulative ranking curve (SUCRA) scores in the prevention of major bleeding events, while in the prevention of ischemic events, rivaroxaban showed a higher SUCRA score (0.78-0.92) in mild RI patients and dabigatran showed a higher SUCRA value (0.90-0.99) in moderate RI patients.

CONCLUSIONS AND RELEVANCE

In the systematic review and meta-analysis, for AF or VTE patients with RI, direct oral anticoagulants performed comparably to or better than warfarin with regard to safety and effects. The network meta-analysis indicated that for patients with mild RI, apixaban might be safer for patients with a lower risk of ischemic events, while rivaroxaban might be suitable for patients with a lower risk of bleeding events. For patients with moderate RI, apixaban could reduce the risk of ischemic events without increasing the risk of bleeding events. For AF patients with severe RI, apixaban, rivaroxaban, and warfarin showed a similar effect. These results might provide suggestions for clinical arterial and venous thrombosis prevention.

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.

Dental implants and risk of bleeding in patients on oral anticoagulants: a systematic review and meta-analysis

Background

Dental implant placement is safe and predictable, yet optimal management of anticoagulated patients remains controversial. Whilst cessation of anticoagulation pre-operatively should decrease risks of bleeding, risk of thrombosis increases. We aim to define risk of bleeding in patients on oral anticoagulation who are undergoing dental implant placement, in order to establish best management.

Methods

This systematic review is registered with the National Institute for Health Research (NIHR) PROSPERO database (Registration No: CRD42021233929). We performed a systematic review as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. Studies were identified using an agreed search strategy within the OVID Gateway (this included Pubmed, MEDLINE, Cochrane Collaborative). Studies assessing bleeding complications in patients who were undergoing dental implant placement were selected. The primary outcome was bleeding events in anticoagulated patients undergoing dental implant placement. Secondary outcomes included any complication requiring further intervention.

Results

We identified 182 studies through screening, and after review of titles and abstracts reduced this to 8 studies. In these studies, 1467 participants received at least 2366 implants. Studies were analysed for quality using the ROBINS-I risk of bias tool. Four studies were retrospective case reviews, and four were prospective reviews, three of which also blinded the operator to anticoagulation status. There was significant heterogeneity between the included studies. Meta-analysis showed an increased risk of bleeding (RR, 2.30; 95% CI, 1.25-4.24 p = 0.37 I = 7%) when implants were placed in the presence of anticoagulation however these were not clinically significant haemorrhagic events.

Conclusion

The continuation of anticoagulants peri-operatively during dental implant surgery does increase the risk of clinically non-significant peri- and post-operative bleeding. Dental implant surgery encompasses a broad spectrum of procedures ranging from minor to more invasive surgery with simple local haemostatic measures mitigating the risk of bleeding. The decision to discontinue anticoagulants prior to dental implant surgery must consider patient and surgical factors with the clinician undertaking a risk-balance assessment.

Antithrombotics in Patients With a Femoral Neck Fracture: Evaluating Daily Practice in an Observational Cohort Study

INTRODUCTION

Geriatric hip fracture patients are characterized by frailty due to multiple comorbidities, such as cardiovascular disease, in which the use of antithrombotics is frequent. The aim of this study is to assess the effect of antithrombotics on perioperative care and patient outcomes after hip hemiarthroplasty following current guidelines.

MATERIALS AND METHODS

This observational cohort study included all consecutively admitted patients with a femoral neck fracture requiring hip hemiarthroplasty between January 1st 2010, and May 16th 2016, in two level II trauma teaching hospitals. Patients with multiple trauma injuries were excluded.

RESULTS

In total, n = 907 patients (68% female (n = 615), median age 84 years) were included of which n = 142 used a vitamin K antagonist (VKA) and n = 213 used antiplatelet (AP) therapy. Both were associated with more packed cell supplementation (.4 ± 1.1 units and .3 ± .8 units vs .2 ± .6 units, P < .001 and P = .03, respectively). VKA was associated with more hematomas compared no antithrombotics (23% vs 11%, P = .001). VKA had a longer time to surgery compared to no antithrombotics and AP (24 hours vs 19 and 20 hours, P < .001 and P < .001, respectively) and longer admission duration (9 days vs 7 days P < .001. There were no differences in 30 day mortality nor in 1-year mortality rates.

DISCUSSION

All modifiable causes for deep SSI, such as hematomas, should be prevented in acute hip fracture surgery. Since antithrombotics are associated with hematomas, an optimal handling in perioperative setting is necessary.

CONCLUSION

VKA was associated with longer time to surgery, more hematomas, and longer admission duration. VKA and AP were associated with more packed cell supplementation.

Andexanet Alfa Use for Small Bowel Obstruction Patient With History of Sugiura Procedure

This case report is about a 51-year-old active duty male with JAK2 mutation and medical history significant for prehepatic portal hypertension from portal vein thrombus on lifelong anticoagulation with rivaroxaban, an oral factor Xa inhibitor, presenting with closed-loop small bowel obstruction requiring emergent laparotomy. We present this surgical case as it required emergent reversal of the oral factor Xa inhibitor with andexanet alfa.

ROTEM Testing for Direct Oral Anticoagulants

Direct oral anticoagulants (DOACs) are increasingly used worldwide for the prevention of stroke in patients with atrial fibrillation and to prevent or treat venous thromboembolism. In situations such as serious bleeding, the need for urgent surgery/intervention or the management of a thromboembolic event, the laboratory measurement of DOACs levels or anticoagulant activity may be required. Rotational thromboelastometry (ROTEM) is a viscoelastic hemostatic assay (VHA) which has been used in emergencies (trauma and obstetrics), and surgical procedures (cardiac surgery and liver transplants), but experience with this assay in DOACs-treated patients is still limited. This article reviews the use of ROTEM in the setting of DOACs therapy, focusing on DOACs-associated bleeding and the use of this VHA for the management of reversal strategies for DOACs-associated anticoagulation.

Efficacy and Safety of Perioperative Bridging Anticoagulation in Patients with Atrial Fibrillation Undergoing Elective Surgical Procedures: A Meta-analysis

Objective: The study objective was to determine if peri-operative bridging anticoagulation in patients with atrial fibrillation is beneficial or harmful.Design: Systematic review and meta-analysis.Setting: Inpatient or in-hospital setting.Participants: Adults with atrial fibrillation having a CHADS2 score >1 undergoing elective surgical procedure on anticoagulation.Methods: A systemic search of multiple databases (Cochrane, Medline, PubMed) was performed regarding studies conducted on efficacy and safety of perioperative bridging anticoagulation in patients with atrial fibrillation. Studies identified were reviewed by two authors individually before inclusion. The results were then pooled using Review Manager to determine the combined effect. Stroke/systemic embolism was considered as the primary efficacy outcome. Major bleeding was the primary safety outcome.Results: The systematic search revealed 108 potential articles. The full texts of 28 articles were retrieved for assessment of eligibility. After full text review, 25 articles were excluded. Three articles met inclusion criteria. No significant difference in stroke/systemic embolism with bridging anticoagulation was noted (risk ratio, 1.25-95% confidence interval [CI], 0.55-2.85). Bridging was associated with significantly higher risk of major bleeding (risk ratio, 3.29-95% CI, 2.25-4.81).Conclusion: An individualized approach is required when initiating peri-operative bridging anticoagulation. There is certainly a higher risk of bleeding with bridging anticoagulation and no difference in stroke/systemic embolism. However, the results cannot be extrapolated to patients who have valvular atrial fibrillation or CHADS2 score of 5 or greater.

Emergency cardiac surgery for patients on NOACs in the NOAC era - Perspective

Excessive bleeding is an important cause of morbidity and mortality after cardiac surgery. Bleeding after cardiac surgery is multifactorial. Adherence to the proverbial 6 Ps remains the cornerstone of any strategy for management of postoperative bleeding after cardiac surgery. Recent years have seen a surge in the number of patients who have been prescribed novel oral anticoagulants (NOACs) for the prevention and treatment of thromboembolic events. This phenomenon has significant repercussions particularly for patients presenting for emergency cardiac surgery. The published evidence guiding management of such patients is limited and in the form of expert consensus. Plasma levels of NOAC >30 ng/ml necessitate specific therapeutic interventions to tackle excessive bleeding attributed to NOAC intake. Current recommendation is to consider using specific reversal agent if available. Otherwise, use of prothrombin complex concentrates is recommended.

Edoxaban (LIXIANA®) in the treatment of venous thromboembolism

Standard therapy for venous thromboembolism (VTE) includes the use of heparins and vitamin K antagonists. Randomized clinical trials have shown that non-vitamin K oral anticoagulants are as effective and safe as standard therapy in VTE treatment, with an improved pharmacological profile. Edoxaban, a direct inhibitor of factor Xa, has demonstrated noninferiority to standard therapy for the treatment of VTE, preserving a high safety profile even in long-term therapy, in frail patients and in severe clinical presentations. The present paper focuses on the role of edoxaban in VTE treatment, from general population to cancer patients, presenting the available data from randomized clinical trials and real world, to discuss edoxaban use in clinical practice.

Mechanisms, Prevention, and Treatment of Atrial Fibrillation After Cardiac Surgery: A Narrative Review

New onset of postoperative atrial fibrillation (AF) generally is recognized as a frequent and debilitating complication after cardiac surgery, contributing to a considerable health- care cost. Extensive research has been conducted to study the underlying mechanisms and risk factors of AF in the perioperative period. Many options have been suggested to lower the incidence, and the concurrent cost in health resources. This review attempts to synthesize the large body of existing literature on AF, as well as expand and illustrate the available knowledge on its management strategies. The latter incorporates recent developments in the anesthesthetic approach as well as in the pharmacologic arsenal. In addition, the current review provides a tool for understanding the pathophysiology of AF and for reducing the occurrence after cardiac surgery. By using it, clinicians can manage patients with AF in the perioperative period of cardiac surgery and minimize the relatively high economic cost that accompanies it.

Studies on fragment-based design of allosteric inhibitors of human factor XIa

Human factor XIa (hFXIa) has emerged as an attractive target for development of new anticoagulants that promise higher level of safety. Different strategies have been adopted so far for the design of anti-hFXIa molecules including competitive and non-competitive inhibition. Of these, allosteric dysfunction of hFXIa's active site is especially promising because of the possibility of controlled reduction in activity that may offer a route to safer anticoagulants. In this work, we assess fragment-based design approach to realize a group of novel allosteric hFXIa inhibitors. Starting with our earlier discovery that sulfated quinazolinone (QAO) bind in the heparin-binding site of hFXIa, we developed a group of two dozen dimeric sulfated QAOs with intervening linkers that displayed a progressive variation in inhibition potency. In direct opposition to the traditional wisdom, increasing linker flexibility led to higher potency, which could be explained by computational studies. Sulfated QAO 19S was identified as the most potent and selective inhibitor of hFXIa. Enzyme inhibition studies revealed that 19S utilizes a non-competitive mechanism of action, which was supported by fluorescence studies showing a classic sigmoidal binding profile. Studies with selected mutants of hFXIa indicated that sulfated QAOs bind in heparin-binding site of the catalytic domain of hFXIa. Overall, the approach of fragment-based design offers considerable promise for designing heparin-binding site-directed allosteric inhibitors of hFXIa.

When to Consider Deferral of Surgery in Acute Type A Aortic Dissection: A Review

Background

Acute type A aortic dissection (ATAAD) is a surgical emergency with an operative mortality of up to 30%, a rate which has not changed meaningfully in over two decades. A growing body of research has highlighted several comorbidities and presenting factors in which delay or permanent deferral of surgery may be considered; however, modern comprehensive summative reviews are lacking. The urgency and timing of this review are underscored by significant challenges in resource utilization posed by the COVID-19 pandemic. This review provides an update on the current understanding of risk assessment, surgical candidacy, and operative timing in patients with ATAAD.

Methods

A literature search was conducted through PubMed and Embase databases to identify relevant studies relating to risk assessment in ATAAD. Articles were selected via group consensus based on quality and relevance.

Results

Several patient factors have been identified which increase risk in ATAAD repair. In particular, frailty, advanced age, prior cardiac surgery, and use of novel anticoagulant medications have been studied. The understanding of malperfusion syndromes has also expanded significantly, including recommendations for surgical delay. Finally, approaches to triage have been significantly influenced by resource limitations related to the ongoing COVID-19 pandemic. While medical management remains a reasonable option in carefully selected patients at prohibitive risk for open surgery, endovascular therapies for treatment of ATAAD are rapidly evolving.

Conclusions

Early surgical repair remains the preferred treatment for most patients with ATAAD, however, improvements in risk stratification should guide appropriate delay or permanent deferral of surgery in select individuals.

Efficacy and safety of direct oral anticoagulants vs. low molecular weight heparin for cancer-related venous thromboembolism: a meta-analysis of randomized trials

AIMS

To examine the efficacy and safety of direct oral anticoagulants (DOACs) vs. low molecular weight heparin (LMWH) in patients with cancer-related venous thromboembolism (VTE).

METHODS AND RESULTS

An electronic search of the MEDLINE, SCOPUS, and Cochrane databases without language restrictions was performed through April 2020 for randomized controlled trials that compared the outcomes with DOACs vs. LMWH among patients with cancer-related VTE. Summary estimates were reported using random effects model. The main efficacy outcome was VTE recurrence, while the main safety outcome was major bleeding . The final analysis included four randomized trials with a total of 2907 patients. The weighted mean follow-up was 6.1 months. Compared with LMWH, DOACs were associated with lower incidence of VTE recurrence [5.7% vs. 9.1%, risk ratio (RR) 0.62; 95% confidence interval (CI) 0.44-0.87; P = 0.01], driven by lower incidence of deep venous thrombosis (RR 0.60, 95% CI 0.39-0.93; P = 0.02). There was no difference in the incidence of major bleeding between DOACs and LMWH (4.8% vs. 3.6%, RR 1.33; 95% CI 0.84-2.11; P = 0.23). The incidence of all-cause mortality was similar (RR 0.99; 95% CI 0.84-1.16; P = 0.91). Subgroup analysis suggested no differences according to the type of DOAC regarding recurrent VTE or major bleeding (Pinteraction = 0.53 and Pinteraction = 0.11, respectively).

CONCLUSION

Among patients with cancer-related VTE, DOACs were associated with lower incidence of VTE recurrence and no difference in the incidence of major bleeding compared with LMWH. Future studies examining the subset of cancer patients who drive the most benefit are encouraged.

Epistaxis management on COVID-19-positive patients: Our early case experience and treatment

Epistaxis management on COVID‐19 patients is concerning for otolaryngologists due to the highly virulence and increased concentration within respiratory droplets and nasal secretions. Authors suggest initial management with oxymetazoline nasal drops and local pressure before considering nasal packing with absorbable material to prevent COVID‐19 transmission to surrounding healthcare workers.

Anticoagulation in Deep Venous Thrombosis: Current Trends in the Era of Non- Vitamin K Antagonists Oral Anticoagulants

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Anticoagulation therapy is the cornerstone of treatment in acute vein thrombosis (DVT) and it aims to reduce symptoms, thrombus extension, DVT recurrences, and mortality. The treatment for DVT depends on its anatomical extent, among other factors. Anticoagulation therapy for proximal DVT is clearly recommended (at least for 3 months), while AT for isolated distal DVT should be considered, especially in the presence of high thromboembolic risk factors. The optimal anticoagulant and duration of therapy are determined by the clinical assessment, taking into account the thromboembolic and bleeding risk in each patient in a case-by-case decision making. Non-Vitamin K antagonists oral anticoagulants (NOACs) were a revolution in the anticoagulation management of DVT. Nowadays, NOACs are considered as first-line therapy in the anticoagulation therapy for DVT and are recommended as the preferred anticoagulant agents by most scientific societies. NOACs offer a simple route of administration (oral agents), a rapid onset-offset of their action along with a good efficacy and safety profile in comparison with Vitamin K Antagonists (VKAs). However, there are issues about their efficacy and safety profile in specific populations with high thromboembolic and bleeding risks, such as renal failure patients, active-cancer patients, and pregnant women, in which VKAs and heparins were the standard care of treatment. Since the available data are promising for the use of NOACs in end-stage chronic kidney disease and cancer patients, several ongoing randomized trials are currently trying to solve that issues and give evidence about the safety and efficacy of NOACs in these populations.

Treatment strategies for patients with atrial fibrillation and anticoagulant-associated intracranial hemorrhage: an overview of the pharmacotherapy

INTRODUCTION

Oral anticoagulants (OAC) reduce stroke/systemic embolism and mortality risks in atrial fibrillation (AF). However, there is an inherent bleeding risk with OAC, where intracranial hemorrhage (ICH) is the most feared, disabling, and lethal complication of this therapy. Therefore, the optimal management of OAC-associated ICH is not well defined despite multiple suggested strategies.

AREAS COVERED

In this review, the authors describe the severity and risk factors for OAC-associated ICH and the associated implications for using DOACs in AF patients. We also provide an overview of the management of OAC-associated ICH and treatment reversal strategies, including specific and nonspecific reversal agents as well as a comprehensive summary of the evidence about the resumption of DOAC and the optimal timing.

EXPERT OPINION

In the setting of an ICH, supportive care/measures are needed, and reversal of anticoagulation with specific agents (including administration of vitamin K, prothrombin complex concentrates, idarucizumab and andexanet alfa) should be considered. Most patients will likely benefit from restarting anticoagulation after an ICH and permanently withdrawn of OAC is associated with worse clinical outcomes. Although the timing of OAC resumption is still under debate, reintroduction after 4-8 weeks of the bleeding event may be possible, after a multidisciplinary approach to decision-making.

A Review on the Use of Reversal Agents of Direct Oral Anticogulant Drugs in Case of Gastrointestinal Bleeding

BACKGROUND

Major bleeding is a life-threatening condition and a medical emergency with high mortality risk. It is often the complication of anticoagulant's intake. Anticoagulants are commonly used for the prevention and treatment of thrombotic events. The standard therapy with vitamin K antagonist (warfarin) has been frequently replaced by direct oral anticoagulants (DOACs). The latter agents (rivaroxaban, apixaban, edoxaban, dabigatran, and betrixaban) showed better efficacy and safety compared to standard warfarin treatment and they are recommended for the reduction of ischemic stroke. Literature data reported a high risk of gastrointestinal bleeding with DOACs, in particular with dabigatran and rivaroxaban. In case of life-threatening gastrointestinal bleeding, these patients could benefit from the use of reversal agents.

METHODS

We performed an electronic search on PUBMED of the literature concerning reversal agents for DOACs and gastrointestinal bleeding in the Emergency Department from 2004 to 2020.

AIM

This review summarizes the current evidence about three reversal agents idarucizumab, andexanet alfa and ciraparantag, and the use of the first two in the emergency setting in patients with active major bleeding or who need urgent surgery which physicians indicate for a better management approach in order to increase patient's safety.

CONCLUSION

Although these agents have been marketed for five years (idarucizumab) and two years (andexanet alfa) respectively, and despite guidelines considering antidotes as first-line agents in treating life-threatening hemorrhage when available, these antidotes seem to gain access very slowly in the clinical practice. Cost, logistical aspects and need for plasma level determination of DOAC for an accurate therapeutic use probably have an impact on this phenomenon.. An expert multidisciplinary bleeding team should be established so as to implement international guidelines based on local resources and organization.