Life-threatening vaginal bleeding after starting rivaroxaban treatment.

This is a case report of a 44-year-old premenopausal woman who was admitted to hospital due to uncontrollable and life-threatening vaginal bleeding after starting rivaroxaban treatment for atrial fibrillation. She had a medical history with menorrhagia due to an intrauterine fibroma. She did not respond sufficiently to factor X supplement or other non-surgical medical interventions. The bleeding subsided after bilateral embolization of aa. uterinae.

Effective application of a direct-acting oral anticoagulants reversal agent in acute type A aortic dissection repair: A case report.

There are insufficient reports on the use of andexanet alfa in cardiac surgery. A 67-year-old man was diagnosed with type A aortic dissection and performed emergent surgery. His medical history included atrial fibrillation treated with Edoxaban. We performed total arch replacement. Despite administration of enough protamine, fresh frozen plasma, and platelet administration, controlling bleeding was difficult. Thus, Andexanet Alfa was initiated after CPB withdrawal. Surgical bleeding was dramatically controlled after its administration. There were no findings suggestive of an embolic event. In conclusion, administration of Andexanet Alfa is safe after cardiopulmonary bypass withdrawal.

[Interference of oral anti-Xa anticoagulants during monitoring of unfractionated heparin treatments: practical and future attitudes]. / Interférence des anticoagulants oraux directs anti-Xa lors de la surveillance des traitements par héparine non-fractionnée : attitudes pratiques et à venir.

Contrary to direct oral anticoagulants (DOAC), unfractionated heparin (UFH) requires daily monitoring when administered at therapeutic dose. At present, UFH monitoring is preferably carried out by measuring plasma anti-Xa activity, however, in patients previously treated with an anti-Xa DOAC and switched to UFH, there is a high risk of DOAC interfering with the measurement of UFH anti-Xa activity. Residual anti-Xa DOAC in the sample can lead to an overestimation of the anticoagulant activity attributed to heparin and thus to incorrect anticoagulation. This risk of interference should not be overlooked because interference may occur even at concentration of DOAC below the hemostatic safety threshold and can last several days. To overcome this issue, several alternatives are being studied. This note provides an update on anti-Xa DOAC interference and different strategies available in current practice. It also underlines the importance of communication between biologists and clinicians on anticoagulant treatments received by patients.

[Is monitoring of anti-factor Xa levels required for low molecular weight heparin prophylaxis of venous thromboembolism in critically ill patients?]

The incidence and mortality of venous thromboembolism (VTE) are high in critically ill patients, and there is still a risk of VTE and bleeding after the use of fixed-dose low molecular weight heparin (LMWH) for prophylaxis. The level of anti-factor Xa is not up to standard after LMWH prophylaxis in patients with surgery or trauma. The condition of critically ill patients is complicated, and the proportion of patients with low antithrombin III is high, which can affect the prophylactic efficacy of LMWH and contribute to VTE occurrence. There is currently no consensus on whether adjusting LMWH dose according to anti-factor Xa levels can reduce VTE occurrence in critically ill patients. High-quality multicenter randomized controlled studies are needed in the future to establish new approaches for precise prevention of VTE in critically ill patients.

In cryptogenic stroke and atrial cardiopathy, apixaban did not reduce recurrent stroke vs. aspirin.

SOURCE CITATION: Kamel H, Longstreth WT Jr, Tirschwell DL, et al; ARCADIA Investigators. Apixaban to prevent recurrence after cryptogenic stroke in patients with atrial cardiopathy: the ARCADIA randomized clinical trial. JAMA. 2024;331:573-581. 38324415.

Pharmacokinetics of single-dose rivaroxaban under fed state in obese vs. non-obese subjects: An open-label controlled clinical trial (RIVOBESE-PK).

The evidence of rivaroxaban's pharmacokinetics in obese compared with non-obese populations remains inconclusive. We aimed to compare the pharmacokinetic profile of rivaroxaban between obese and non-obese populations under fed state. Participants who met the study's eligibility criteria were assigned into one of two groups: obese (body mass index ≥35 kg/m2) or non-obese (body mass index 18.5-24.9 kg/m2). A single dose of rivaroxaban 20 mg was orally administered to each participant. Nine blood samples over 48 h, and multiple urine samples over 18 h were collected and analyzed for rivaroxaban concentration using ultra-performance liquid chromatography coupled with tandem mass detector. Pharmacokinetic parameters were determined using WinNonlin software. Thirty-six participants were recruited into the study. No significant changes were observed between obese and non-obese participants in peak plasma concentration, time to reach peak plasma concentration, area under the plasma concentration-time curve over 48 h or to infinity, elimination rate constant, half-life, apparent volume of distribution, apparent clearance, and fraction of drug excreted unchanged in urine over 18 h. Rivaroxaban's exposure was similar between the obese and non-obese subjects, and there were no significant differences in other pharmacokinetic parameters between the two groups. These results suggest that dose adjustment for rivaroxaban is probably unwarranted in the obese population.

Periprocedural Edoxaban Management and Clinical Outcomes in Patients Undergoing Transcatheter Cardiovascular Procedures in the EMIT-AF/VTE Program.

Clinical trial registration number: NCT02950168, NCT02951039.

Effect of drug interactions with non-vitamin-K oral anticoagulants on thromboembolic events in patients with nonvalvular atrial fibrillation.

Introduction: Few real-world studies have investigated drug-drug interactions (DDIs) involving non-vitamin-K antagonist oral anticoagulants (NOACs) in patients with nonvalvular atrial fibrillation (NVAF). The interactions encompass drugs inducing or inhibiting cytochrome P450 3A4 and permeability glycoprotein. These agents potentially modulate the breakdown and elimination of NOACs. This study investigated the impact of DDIs on thromboembolism in this clinical scenario. Method: Patients who had NVAF and were treated with NOACs were selected as the study cohort from the National Health Insurance Research Database of Taiwan. Cases were defined as patients hospitalised for a thromboembolic event and who underwent a relevant imaging study within 7 days before hospitalisa-tion or during hospitalisation. Each case was matched with up to 4 controls by using the incidence density sampling method. The concurrent use of a cytochrome P450 3A4/permeability glycoprotein inducer or inhibitor or both with NOACs was identified. The effects of these interactions on the risk of thromboembolic events were examined with univariate and multivariate conditional logistic regressions. Results: The study cohort comprised 60,726 eligible patients. Among them, 1288 patients with a thromboembolic event and 5144 matched control patients were selected for analysis. The concurrent use of a cytochrome P450 3A4/permeability glycoprotein inducer resulted in a higher risk of thromboembolic events (adjusted odds ratio [AOR] 1.23, 95% confidence interval [CI] 1.004-1.51). Conclusion: For patients with NVAF receiving NOACs, the concurrent use of cytochrome P450 3A4/ permeability glycoprotein inducers increases the risk of thromboembolic events.

Observational study of frailty in older Japanese patients with non-valvular atrial fibrillation receiving anticoagulation therapy.

The number of patients with atrial fibrillation is increasing, and frailty prevalence increases with age, posing challenges for physicians in prescribing anticoagulants to such patients because of possible harm. The effects of frailty on anticoagulant therapy in older Japanese patients with nonvalvular atrial fibrillation (NVAF) are unclear. Herein, we prescribed rivaroxaban to Japanese patients with NVAF and monitored for a mean of 2.0 years. The primary endpoint was stroke or systemic embolism. The secondary endpoints were all-cause or cardiovascular death, composite endpoint, and major or non-major bleeding. Frailty was assessed using the Japanese long-term care insurance system. A multiple imputation technique was used for missing data. The propensity score (PS) was obtained to estimate the treatment effect of frailty and was used to create two PS-matched groups. Overall, 5717 older patients had NVAF (mean age: 73.9 years), 485 (8.5%) were classified as frail. After PS matching, background characteristics were well-balanced between the groups. Rivaroxaban dosages were 10 and 15 mg/day for approximately 80% and the remaining patients, respectively. Frailty was not associated with the primary endpoint or secondary endpoints. In conclusion, frailty does not affect the effectiveness or safety of rivaroxaban anticoagulant therapy in older Japanese patients with NVAF.Trial registration: UMIN000019135, NCT02633982.

Efficacy and Safety of Rivaroxaban for Extremely Aged Patients with Venous Thromboembolism: A Retrospective, Cross-Sectional Real-World Study.

Background: Rivaroxaban, a non-vitamin K antagonist oral anticoagulant, has become widely used for the management of venous thromboembolism (VTE) in adult patients. However, few trials have explored the efficacy and safety of rivaroxaban in VTE patients over 80 years of age. This necessitates further real-world studies of rivaroxaban across elderly populations. Methods: We performed a retrospective single center study involving extremely aged VTE sufferers treated with rivaroxaban. The sample comprised 121 patients newly initiated on rivaroxaban diagnosed between January 2018 and January 2020. Patients were followed up for no less than 2 years. The effectiveness outcome was the disappearance of thromboembolism. The safety outcome was the incidence of major bleeding events. Comorbidities and complications were recorded throughout the entire study. Results: The efficacy outcome occurred in 114 of 121 patients (94.21%) and the safety outcome occurred in 12 of 121 patients (9.91%). Increased hemorrhages were observed in patients with infection (15.15% vs 7.80%), but no significant difference was observed due to limited sample size (P=0.3053). Patients with an age-adjusted Charlson comorbidity index score higher than 6 points exhibited higher bleeding rates (14.08% vs 4.00%; P=0.0676) and lower thrombus cure rates (88.73% vs 100%; P=0.0203). Key conclusions: Patients with infection should be more careful of bleeding events during rivaroxaban therapy. An age-adjusted Charlson comorbidity index score higher than 6, which predicted poor survival, indicated inferior safety and efficacy of rivaroxaban. Aim: To investigate the efficacy and safety of Rivaroxaban in an aged venous thromboembolism patient population under real-world conditions.

Clinical guidance for unfractionated heparin dosing and monitoring in critically ill patients.

INTRODUCTION: Unfractionated heparin is a widely used anticoagulant in critically ill patients. It has a well-established safety profile and remains an attractive option for clinicians due to its short half-life and reversibility. Heparin has a unique pharmacokinetic profile, which contributes to significant inter-patient and intra-patient variability in effect. The variability in anticoagulant effect combined with heparin's short half-life mean close monitoring is required for clinical efficacy and preventing adverse effects. To optimize heparin use in critically ill patients, effective monitoring assays and dose adjustment strategies are needed. AREAS COVERED: This paper explores the use of heparin as an anticoagulant and optimal approaches to monitoring in critically ill patients. EXPERT OPINION: Conventional monitoring assays for heparin dosing have significant limitations. Emerging data appear to favor using anti-Xa assay monitoring for heparin anticoagulation, which many centers have successfully adopted as the standard. The anti-Xa assay appears have important benefits relative to the aPTT for heparin monitoring in critically ill patients, and should be considered for broader use.

Cost-Effectiveness and Budget Impact Analysis of Apixaban and Rivaroxaban Versus Warfarin in the Prevention of Stroke in Patients With Non-Valvular Atrial Fibrillation (NVAF) in Iran.

INTRODUCTION: This study evaluates the cost-effectiveness of Apixaban and Rivaroxaban, compared to Warfarin, for stroke prevention in patients with non-valvular atrial fibrillation in Iran. METHOD: A Markov model with a 30-year time horizon was employed to simulate and assess different treatment strategies' cost-effectiveness. The study population comprised Iranian adults with NVAF, identified through specialist consultations, hospital visits, and archival record reviews. Direct medical costs, direct nonmedical, and indirect costs were included. Quality-adjusted life years (QALY) were assessed using an EQ-5D questionnaire. This study utilized a cost-effectiveness threshold of $11 134 per QALY. RESULTS: Apixaban demonstrated superior cost-effectiveness compared to Rivaroxaban and Warfarin. Over 30 years, total costs were lower in the Apixaban and Rivaroxaban groups compared to the Warfarin group ($126.18 and $109.99 vs. $150.49). However, Apixaban showed higher total QALYs gained compared to others (0.134 vs. 0.133 and 0.116). The incremental cost-effectiveness ratio for comparing Apixaban to Warfarin was calculated at -1332.83 cost per QALY, below the threshold of $11 134, indicating Apixaban's cost-effectiveness. Sensitivity analyses confirmed the robustness of the findings, with ICER consistently remaining below the threshold. Over 5 years (2024-2028) of Apixaban usage, the incremental cost starts at USD 70 250 296 in the first year and gradually rises to USD 71 770 662 in the fifth year. DSA and PSA were assessed to prove the robustness of the results. CONCLUSION: This study shows that Apixaban is a cost-effective option for stroke prevention in non-valvular atrial fibrillation patients in Iran compared to Warfarin.

Efficacy and Safety of Direct Oral Anticoagulants for Acute Treatment of Venous Thromboembolism in Older Adults: A Network Meta-Analysis of Randomised Controlled Trials.

OBJECTIVE: This systematic review and network meta-analysis aimed to evaluate the efficacy and safety of direct oral anticoagulants (DOACs) in adults aged 75 and over undergoing acute venous thromboembolism (VTE) treatment. METHODS: PubMed, Embase and the CENTRAL were searched up to 25 December 2023. The incidence of VTE recurrence and bleeding events was assessed. Employing a frequentist network meta-analysis approach, interventions not directly compared could be indirectly assessed through the 95% confidence interval (CI), enhancing the interpretability of the search results. The surface under the cumulative ranking curves (SUCRA) was utilized to generate the relative ranking probabilities for each group. RESULTS: Our study, analysing 6 randomised controlled trials with 3665 patients, compares direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) in adults aged 75 and over with acute venous thromboembolism. Edoxaban reduces VTE recurrence risk compared with VKAs (risk ratio [RR] .50, 95% CI 0.27 - .95), while apixaban significantly decreases bleeding risk compared with VKAs (RR .23, 95% CI 0.08 - .69), edoxaban (RR .28, 95% CI 0.09 - .86) and rivaroxaban (RR .28, 95% CI 0.09 - .86). Despite low overall evidence quality, apixaban consistently ranks highest for both efficacy and safety. Findings underscore the nuanced efficacy-safety balance in this population, emphasizing cautious interpretation due to evidence limitations. CONCLUSION: Apixaban emerges as a favourable choice for acute VTE treatment in the elderly, displaying reduced bleeding risk compared to other treatments while maintaining comparable efficacy. Future studies should explore diverse anticoagulants efficacy and safety in older populations. Additionally, clinical prediction models tailored to geriatric cohorts are crucial for guiding treatment duration decisions.

Long-term effectiveness and safety of edoxaban in patients with atrial fibrillation: 4-year data from the ETNA-AF-Europe study.

BACKGROUND: To assess long-term effectiveness and safety of edoxaban in Europe. METHODS AND RESULTS: ETNA-AF-Europe, a prospective, multinational, multi-centre, post-authorisation, observational study was conducted in agreement with the European Medicines Agency. The primary and secondary objectives assessed real-world safety (including bleeding and deaths) and effectiveness (including stroke, systemic embolic events and clinical edoxaban use), respectively. Median (interquartile range) age of the 13,164 patients was 75.0 (68.0-80.0) years; CHA2DS2-VASc and HAS-BLED scores were 3.0 (2.0-4.0) and 2.0 (1.0-2.0), respectively. Follow-up duration was 3.98 (3.21-4.05) years. Patients on edoxaban 30 mg (n = 3042) at baseline were older (80.0 vs 73.0 years), more likely assessed as frail by investigators (27.0% vs 6.6%) and had more comorbidities than those on edoxaban 60 mg (n = 9617; missing dosing information for n = 505). Annualised event rates of all-cause and cardiovascular death in the overall population, edoxaban 60 mg and edoxaban 30 mg groups were 4.1%, 2.8% and 8.4%, and 1.0%, 0.7% and 2.0%, respectively. Annualised rates of stroke were relatively constant throughout the follow-up, transient ischaemic attack and systemic embolism were < 1% in the overall population. Rates of any major and major gastrointestinal bleeding were low, with slightly higher rates for edoxaban 30 vs 60 mg group. Intracranial haemorrhage was uncommon (0.2%). CONCLUSIONS: In European patients with AF, long-term therapy with edoxaban is associated with low and relatively constant annualised rates of stroke and major bleeding. Differences in outcomes between the two approved doses are attributable to differences in clinical characteristics.

Safety and efficacy of apixaban versus vitamin K antagonists in patients undergoing dialysis: a systematic review and meta-analysis.

BACKGROUND: This review aims to evaluate the safety and efficacy of apixaban vs. vitamin K antagonists (VKAs) in patients on dialysis. METHODS: All types of studies published on PubMed, Embase, CENTRAL, and Web of Science up to 10 September 2023 and comparing outcomes of apixaban vs. VKA in dialysis patients were eligible. RESULTS: Two randomized controlled trials (RCTs) and six retrospective studies were included. Apixaban treatment was associated with significantly lower risk of major bleeding (RR: 0.61; 95% CI: 0.48, 0.77; I2 = 50%) and clinically relevant non-major bleeding (RR: 0.82, 95% CI: 0.68, 0.98, I2 = 9%) compared to VKA. Meta-analysis also showed that the risk of gastrointestinal bleeding (RR: 0.74, 95% CI: 0.64, 0.85, I2 = 16%) and intracranial bleeding (RR: 0.64, 95% CI: 0.49, 0.84, I2 = 0%) was significantly reduced with apixaban. Meta-analysis showed no difference in the risk of ischemic stroke (RR: 0.40, 95% CI: 0.06, 2.69, I2 = 0%), mortality (RR: 1.26, 95% CI: 0.74, 2.16, I2 = 94%) and recurrent venous thromboembolism (RR: 1.02, 95% CI: 0.87, 1.21, I2 = 0%) between the two groups. Subgroup analysis of RCTs showed no difference in bleeding outcomes. CONCLUSIONS: Low-quality evidence from a mix of RCTs and retrospective studies shows that apixaban may have better safety and equivalent efficacy as compared to VKA in dialysis patients. Apixaban treatment correlated with significantly reduced risk of major bleeding and clinically relevant nonmajor bleeding in observational studies but not in RCTs. The predominance of retrospective data warrants caution in the interpretation of results.

Study Design of a Brazilian Observational Study of Edoxaban in Patients with Atrial Fibrillation (EdoBRA). / Desenho de Estudo de um Estudo Observacional Brasileiro sobre o uso de Edoxabana em Pacientes com Fibrilação Atrial (EdoBRA).

BACKGROUND: Clinical trials showed the safety of Edoxaban, a non-vitamin K-dependent oral anticoagulant (NOAC), and its efficacy to prevent stroke and systemic embolism in non-valvular atrial fibrillation (NVAF) patients and also to prevent and treat venous thromboembolism. However, additional research is needed to evaluate the safety and effectiveness of Edoxaban in a real-world scenario in the Brazilian population. OBJECTIVE: In order to understand the risks and benefits of Edoxaban use in routine clinical settings, the EdoBRA study is being conducted to gain insight into the safety and effectiveness of Edoxaban use in non-preselected patients with NVAF in Brazil. METHODS: The EdoBRA study is a multicenter, prospective, observational study conducted in 36 sites in Brazil. NVAF patients ≥ 18 years treated with commercially available Edoxaban who initiated treatment for at least 14 days and no longer than 90 days prior to enrollment, and who are not simultaneously participating in any interventional study are eligible for this study. Seven hundred patients are planned to be enrolled and one-year of follow up, with data collections expected at baseline and 3, 6, and 12 months after the study enrollment. The primary safety objective is ISTH Clinically Relevant Bleeding, and the secondary effectiveness objective focuses on relevant cardiovascular outcomes related to NVAF. CONCLUSION: EdoBRA observational study will generate relevant additional information about NOAC Edoxaban on various aspects of patient management in routine care, such as its safety and effectiveness profile in patients with NVAF in Brazil.

FUNDAMENTO: Os ensaios clínicos demonstraram a segurança da Edoxabana, um anticoagulante oral não dependente de vitamina K (NOAC), e a sua eficácia na prevenção de acidente vascular cerebral e embolia sistémica em pacientes com fibrilação atrial não valvar (FANV) e também na prevenção e tratamento de tromboembolismo venoso. No entanto, pesquisas adicionais são necessárias para avaliar a segurança e a eficácia da Edoxabana em um cenário real na população brasileira. OBJETIVO: A fim de compreender os riscos e benefícios do uso da Edoxabana em cenários clínicos de rotina, o estudo EdoBRA está sendo conduzido para obter informações sobre a segurança e eficácia do uso da Edoxabana em pacientes não pré-selecionados com FANV no Brasil. MÉTODOS: O estudo EdoBRA é um estudo multicêntrico, prospectivo e observacional, realizado em 36 centros no Brasil. São elegíveis para este estudo pacientes com FANV, ≥ 18 anos de idade, tratados com Edoxabana disponível comercialmente, que iniciaram o tratamento por pelo menos 14 dias e não mais do que 90 dias antes da data de inclusão no estudo, e que não estão participando de nenhum outro estudo de intervenção. Ao todo, 700 pacientes devem ser inscritos e acompanhados por um ano, com coletas de dados programadas para o período basal e 3, 6 e 12 meses após a inscrição no estudo. O objetivo primário de segurança é o sangramento clinicamente relevante (de acordo com critérios da Sociedade Internacional de Trombose e Hemostasia - ISTH), e o objetivo secundário de eficácia são desfechos cardiovasculares relevantes relacionados à FANV. CONCLUSÃO: O estudo observacional EdoBRA gerará informações adicionais relevantes sobre a Edoxabana enquanto NOAC em diversos aspectos do manejo de pacientes no atendimento clínico de rotina, como perfil de segurança e efetividade em pacientes com FANV no Brasil.

Aptameric hirudins as selective and reversible EXosite-ACTive site (EXACT) inhibitors.

Potent and selective inhibition of the structurally homologous proteases of coagulation poses challenges for drug development. Hematophagous organisms frequently accomplish this by fashioning peptide inhibitors combining exosite and active site binding motifs. Inspired by this biological strategy, we create several EXACT inhibitors targeting thrombin and factor Xa de novo by linking EXosite-binding aptamers with small molecule ACTive site inhibitors. The aptamer component within the EXACT inhibitor (1) synergizes with and enhances the potency of small-molecule active site inhibitors by many hundred-fold (2) can redirect an active site inhibitor's selectivity towards a different protease, and (3) enable efficient reversal of inhibition by an antidote that disrupts bivalent binding. One EXACT inhibitor, HD22-7A-DAB, demonstrates extraordinary anticoagulation activity, exhibiting great potential as a potent, rapid onset anticoagulant to support cardiovascular surgeries. Using this generalizable molecular engineering strategy, selective, potent, and rapidly reversible EXACT inhibitors can be created against many enzymes through simple oligonucleotide conjugation for numerous research and therapeutic applications.

Assessment of Days Alive Out of Hospital as a Possible End Point in Trials of Stroke Prevention for Atrial Fibrillation: A ROCKET AF Analysis.

BACKGROUND: Days alive out of hospital (DAOH) is an objective and patient-centered net benefit end point. There are no assessments of DAOH in clinical trials of interventions for atrial fibrillation (AF), and it is not known whether this end point is of clinical utility in these populations. METHODS AND RESULTS: ROCKET AF (Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation) was an international double-blind, double-dummy randomized clinical trial that compared rivaroxaban with warfarin in patients with atrial fibrillation at increased risk for stroke. We assessed DAOH using investigator-reported event data for up to 12 months after randomization in ROCKET AF. We assessed DAOH overall, by treatment group, and by subgroup, including age, sex, and comorbidities, using Poisson regression. The mean±SD number of days dead was 7.3±41.2, days hospitalized was 1.2±7.2, and mean DAOH was 350.7±56.2, with notable left skew. Patients with comorbidities had fewer DAOH overall. There were no differences in DAOH by treatment arm, with mean DAOH of 350.6±56.5 for those randomized to rivaroxaban and 350.7±55.8 for those randomized to warfarin (P=0.86). A sensitivity analysis found no difference in DAOH not disabled with rivaroxaban versus warfarin (DAOH not disabled, 349.2±59.5 days and 349.1 days±59.3 days, respectively, P=0.88). CONCLUSIONS: DAOH did not identify a treatment difference between patients randomized to rivaroxaban versus warfarin. This may be driven in part by the low overall event rates in atrial fibrillation anticoagulation trials, which leads to substantial left skew in measures of DAOH.