[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.

Predictors of adherence to direct oral anticoagulants after cardiovascular or bleeding events in Medicare Advantage Plan enrollees with atrial fibrillation.

BACKGROUND: Direct oral anticoagulants (DOACs) are recommended for patients with atrial fibrillation (AF) given their improved safety profile. Suboptimal adherence to DOACs remains a significant concern among individuals with AF. However, the extent of adherence to DOACs following a cardiovascular or bleeding event has not been fully evaluated. OBJECTIVE: To evaluate the pattern of adherence trajectories of DOACs after a cardiovascular or bleeding event and to investigate the sociodemographic and clinical predictors associated with each adherence trajectory by using claims-based data. METHODS: This retrospective study was conducted among patients with AF prescribed with DOACs (dabigatran/apixaban/rivaroxaban) between July 2016 and December 2017 and who were continuously enrolled in the Texas-based Medicare Advantage Plan. Patients who experienced a cardiovascular or bleeding event while using the DOACs were further included in the analysis. The sample was limited to patients who experienced a clinical event such as a cardiovascular or bleeding event while using the DOACs. The clinical events considered in this study were cardiovascular (stroke, congestive heart failure, myocardial infarction, systemic embolism) and bleeding events. To assess adherence patterns, each patient with a DOAC prescription was followed up for a year after experiencing a clinical event. The monthly adherence to DOACs after these events was evaluated using the proportion of days covered (PDC). A group-based trajectory model incorporated the monthly PDC to classify groups of patients based on their distinct patterns of adherence. Predictors associated with each trajectory were assessed using a multinomial logistic regression model, with the adherent trajectory serving as the reference group in the outcome variable. RESULTS: Among the 694 patients with AF who experienced clinical events after the initiation of DOACs, 3 distinct adherence trajectories were identified: intermediate nonadherent (30.50%), adherent (37.7%), and low adherent (31.8%); the mean PDC was 0.47 for the intermediate nonadherent trajectory, 0.93 for the adherent trajectory, and 0.01 for low adherent trajectory. The low-income subsidy was significantly associated with lower adherence trajectories (odds ratio [OR] = 4.81; 95% CI = 3.07-7.51) and with intermediate nonadherent trajectories (OR = 1.57; 95% CI = 1.06-2.34). Also, nonsteroidal anti-inflammatory drug use was significantly associated with lower adherence trajectories (OR = 5.10; 95% CI = 1.95-13.36) and intermediate nonadherent trajectories (OR = 3.17; 95% CI = 1.26-7.93). Other predictors significantly associated with both nonadherent trajectories are type of DOACs (OR = 0.53; 95% CI = 0.35-0.79), presence of coronary artery disease (OR = 1.89; 95% CI = 1.01-3.55), and having 2 or more clinical events (OR = 1.65; 95% CI = 1.09-2.50). CONCLUSIONS: Predictors identified provide valuable insights into the suboptimal adherence of DOACs among Medicare Advantage Plan enrollees with AF, which can guide the development of targeted interventions to enhance adherence in this high-risk patient population.

Effectiveness of edoxaban in portal vein thrombosis associated with liver cirrhosis.

Portal vein thrombosis (PVT) worsens the long-term prognosis of patients with cirrhosis; however, the optimal treatment remains to be determined. Reports on the efficacy of direct oral anticoagulants are increasing, and further evidence is needed. Therefore, we investigated the effectiveness of treatment with edoxaban in patients with PVT. We retrospectively reviewed the outcomes of edoxaban and warfarin as antithrombotic therapies for PVT. The median overall survival time was 4.2 years in patients with PVT, with a 1-year survival rate of 70.7% and a 5-year survival rate of 47.9%. The leading cause of death was hepatocellular carcinoma. The overall response rate for thrombolysis in the edoxaban group was 76.7% compared to 29.4% in the warfarin group, and edoxaban significantly improved PVT compared to warfarin. In addition, edoxaban provided long-term improvement of PVT. Warfarin, on the other hand, was temporarily effective but did not provide long-term benefits. The Child-Pugh and albumin-bilirubin scores did not change after edoxaban or warfarin use. No deaths occurred due to adverse events associated with edoxaban or warfarin. Edoxaban as a single agent can achieve long-term recanalization without compromising the hepatic reserves. Edoxaban is easy to initiate, even in an outpatient setting, and could become a major therapeutic agent for the treatment of PVT.

Andexanet for Factor Xa Inhibitor-Associated Acute Intracerebral Hemorrhage.

BACKGROUND: Patients with acute intracerebral hemorrhage who are receiving factor Xa inhibitors have a risk of hematoma expansion. The effect of andexanet alfa, an agent that reverses the effects of factor Xa inhibitors, on hematoma volume expansion has not been well studied. METHODS: We randomly assigned, in a 1:1 ratio, patients who had taken factor Xa inhibitors within 15 hours before having an acute intracerebral hemorrhage to receive andexanet or usual care. The primary end point was hemostatic efficacy, defined by expansion of the hematoma volume by 35% or less at 12 hours after baseline, an increase in the score on the National Institutes of Health Stroke Scale of less than 7 points (scores range from 0 to 42, with higher scores indicating worse neurologic deficit) at 12 hours, and no receipt of rescue therapy between 3 hours and 12 hours. Safety end points were thrombotic events and death. RESULTS: A total of 263 patients were assigned to receive andexanet, and 267 to receive usual care. Efficacy was assessed in an interim analysis that included 452 patients, and safety was analyzed in all 530 enrolled patients. Atrial fibrillation was the most common indication for factor Xa inhibitors. Of the patients receiving usual care, 85.5% received prothrombin complex concentrate. Hemostatic efficacy was achieved in 150 of 224 patients (67.0%) receiving andexanet and in 121 of 228 (53.1%) receiving usual care (adjusted difference, 13.4 percentage points; 95% confidence interval [CI], 4.6 to 22.2; P = 0.003). The median reduction from baseline to the 1-to-2-hour nadir in anti-factor Xa activity was 94.5% with andexanet and 26.9% with usual care (P<0.001). Thrombotic events occurred in 27 of 263 patients (10.3%) receiving andexanet and in 15 of 267 (5.6%) receiving usual care (difference, 4.6 percentage points; 95% CI, 0.1 to 9.2; P = 0.048); ischemic stroke occurred in 17 patients (6.5%) and 4 patients (1.5%), respectively. There were no appreciable differences between the groups in the score on the modified Rankin scale or in death within 30 days. CONCLUSIONS: Among patients with intracerebral hemorrhage who were receiving factor Xa inhibitors, andexanet resulted in better control of hematoma expansion than usual care but was associated with thrombotic events, including ischemic stroke. (Funded by Alexion AstraZeneca Rare Disease and others; ANNEXA-I ClinicalTrials.gov number, NCT03661528.).

Development of immediate-release formulation with reliable absorption of rivaroxaban in various meal regimes.

The bioavailability of rivaroxaban at the higher doses (15 and 20 mg) is considerably reduced when the drug is administered on an empty stomach. This can lead to inadequate anticoagulant effect, and therefore, it is recommended to use the higher doses at fed state. However, proper posology may represent a barrier for some patients. Therefore, the aim of this study was to evaluate innovative rivaroxaban-containing formulations designed to eliminate the food effect to ensure reliable absorption and thus to improve patient adherence with the treatment. Three prototypes (Cocrystal, HPMCP and Kollidon) with rivaroxaban were developed and their bioavailability and food effect in comparison to the reference product was tested in open label, randomized, single oral dose, crossover studies, where test products were administered under fasting and fed conditions and the reference product was administered under fed conditions. Comparable bioavailability for all tested prototypes both under fed and fasting conditions was demonstrated as the 90% confidence intervals of the geometric mean ratios for area under the concentration-time curve remained within the standard acceptance range of 80.00%-125.00%. An innovative immediate release form of rivaroxaban with no food effect on drug bioavailability has been developed, which may represent an important step toward increasing adherence, improving treatment outcome and reducing health care costs.

Comparison of apixaban versus aspirin for the prevention of latent bioprosthetic aortic valve thrombosis: study protocol for a prospective randomized trial.

BACKGROUND: The optimal antithrombotic strategy early after aortic valve replacement surgery with a biological valve remains controversial due to lack of high-quality evidence. Either oral anticoagulants or acetylsalicylic acid should be considered for the first 3 months. Hypo-attenuated leaflet thickening on cardiac computed tomography has been associated with latent bioprosthetic valve thrombosis and may be prevented with anticoagulation. We hypothesize that anticoagulation with apixaban is superior to single antiplatelet therapy with acetylsalicylic acid in reducing hypo-attenuated leaflet thickening of bioprosthetic aortic valve prostheses. METHODS: In this prospective, open-label, randomized trial, patients undergoing isolated aortic valve replacement surgery with rapid deployment bioprosthetic valves will be randomized. The treatment group will receive 5 mg of apixaban twice a day for the first 3 months and 100 mg of acetylsalicylic acid thereafter. The control group will be administered 100 mg of acetylsalicylic acid once a day, indefinitely. After the 3-month treatment period, a contrast-enhanced electrocardiogram-gated cardiac computed tomography will be performed to identify hypo-attenuated leaflet thickening of the bioprosthetic valve. The primary objective of the study is to assess the impact of apixaban on the prevention of hypo-attenuated leaflet thickening at 3 months. The secondary and exploratory endpoints will be clinical outcomes and safety profiles of the two strategies. DISCUSSION: Antithrombotic therapy after aortic valve replacement is used to prevent valve thrombosis and systemic thromboembolism. Latent bioprosthetic valve thrombosis is a precursor of clinically significant prosthetic valve dysfunction or thromboembolic events. The hallmark feature of latent bioprosthetic valve thrombosis is hypo-attenuated leaflet thickening on cardiac computed tomography. Subclinical leaflet thrombosis occurs frequently in bioprosthetic aortic valves, more commonly in transcatheter than in surgical valves. There is no evidence on the effect of direct oral anticoagulants on the incidence of hypo-attenuated leaflet thickening after surgical aortic valve replacement with rapid deployment bioprostheses. TRIAL REGISTRATION: ClinicalTrials.gov NCT06184113. Registered on December 28, 2023.

Physiologically based absorption modeling to predict the bioequivalence of two apixaban formulations.

The equivalence of absorption rates and extents between generic drugs and their reference formulations is crucial for ensuring therapeutic comparability. Bioequivalence (BE) studies are widely utilized and play a pivotal role in substantiating the approval and promotional efforts for generic drugs. Virtual BE simulation is a valuable tool for mitigating risks and guiding clinical BE studies, thereby minimizing redundant in vivo BE assessments. Herein, we successfully developed a physiologically based absorption model for virtual BE simulations, which precisely predicts the BE of the apixaban test and reference formulations. The modeling results confirm that the test and reference formulations were bioequivalent under both fasted and fed conditions, consistent with clinical studies. This highlights the efficacy of physiologically based absorption modeling as a powerful tool for formulation screening and can be adopted as a methodological and risk assessment strategy to detect potential clinical BE risks.

Safety and Efficacy of Direct Oral Anticoagulants vs Warfarin in Patients With Obesity and Venous Thromboembolism: A Retrospective Analysis.

BACKGROUND: Current venous thromboembolism guidelines recommend using direct oral anticoagulants (DOACs) over warfarin regardless of obesity status; however, evidence remains limited for the safety and efficacy of DOAC use in patients with obesity. This retrospective analysis sought to demonstrate the safety and efficacy of DOACs compared with warfarin in a diverse population of patients with obesity in light of current prescribing practices. METHODS: A retrospective cohort study was conducted at a large academic health system between July 2014 and September 2019. Adults with an admission diagnosis of deep vein thrombosis (DVT) or pulmonary embolism, with weight greater than 120 kg or a body mass index greater than 40, and who were discharged on an oral anticoagulant were included. Outcomes included occurrence of a thromboembolic event (DVT, pulmonary embolism, or ischemic stroke), bleeding event requiring hospitalization, and all-cause mortality within 12 months following index admission. RESULTS: Out of 787 patients included, 520 were in the DOAC group and 267 were in the warfarin group. Within 12 months of index hospitalization, thromboembolic events occurred in 4.23% of patients in the DOAC group vs 7.12% of patients in the warfarin group (hazard ratio, 0.6 [95% CI, 0.32-1.1]; P = .082). Bleeding events requiring hospitalization occurred in 8.85% of DOAC patients vs 10.1% of warfarin patients (hazard ratio, 0.93 [95% CI, 0.57-1.5]; P = .82). A DVT occurred in 1.7% and 4.9% of patients in the DOAC and warfarin groups, respectively (hazard ratio, 0.35 [95% CI, 0.15-0.84]; P = .046). CONCLUSION: No significant differences could be determined between DOACs and warfarin for cumulative thromboembolic or bleeding events, pulmonary embolism, ischemic stroke, or all-cause mortality. The risk of DVT was lower with apixaban and rivaroxaban. Regardless of patient weight or body mass index, physicians prescribed DOACs more commonly than warfarin.

Xa inhibitor edoxaban ameliorates hepatic ischemia-reperfusion injury via PAR-2-ERK 1/2 pathway.

Hepatic ischemia-reperfusion injury causes liver damage during surgery. In hepatic ischemia-reperfusion injury, the blood coagulation cascade is activated, causing microcirculatory incompetence and cellular injury. Coagulation factor Xa (FXa)- protease-activated receptor (PAR)-2 signaling activates inflammatory reactions and the cytoprotective effect of FXa inhibitor in several organs. However, no studies have elucidated the significance of FXa inhibition on hepatic ischemia-reperfusion injury. The present study elucidated the treatment effect of an FXa inhibitor, edoxaban, on hepatic ischemia-reperfusion injury, focusing on FXa-PAR-2 signaling. A 60 min hepatic partial-warm ischemia-reperfusion injury mouse model and a hypoxia-reoxygenation model of hepatic sinusoidal endothelial cells were used. Ischemia-reperfusion injury mice and hepatic sinusoidal endothelial cells were treated and pretreated, respectively with or without edoxaban. They were incubated during hypoxia/reoxygenation in vitro. Cell signaling was evaluated using the PAR-2 knockdown model. In ischemia-reperfusion injury mice, edoxaban treatment significantly attenuated fibrin deposition in the sinusoids and liver histological damage and resulted in both anti-inflammatory and antiapoptotic effects. Hepatic ischemia-reperfusion injury upregulated PAR-2 generation and enhanced extracellular signal-regulated kinase 1/2 (ERK 1/2) activation; however, edoxaban treatment reduced PAR-2 generation and suppressed ERK 1/2 activation in vivo. In the hypoxia/reoxygenation model of sinusoidal endothelial cells, hypoxia/reoxygenation stress increased FXa generation and induced cytotoxic effects. Edoxaban protected sinusoidal endothelial cells from hypoxia/reoxygenation stress and reduced ERK 1/2 activation. PAR-2 knockdown in the sinusoidal endothelial cells ameliorated hypoxia/reoxygenation stress-induced cytotoxicity and suppressed ERK 1/2 phosphorylation. Thus, edoxaban ameliorated hepatic ischemia-reperfusion injury in mice by protecting against micro-thrombosis in sinusoids and suppressing FXa-PAR-2-induced inflammation in the sinusoidal endothelial cells.

Perioperative Management in Patients with Atrial Fibrillation Treated with Non-Vitamin K Antagonist Oral Anticoagulants Undergoing Minor Bleeding Risk Procedure: Rationale and Protocol for the PERIXa Study.

Background: While treatment interruption of non-vitamin K antagonist oral anticoagulants (NOACs) for elective surgery or procedures among patients with atrial fibrillation (AF) is becoming more prevalent, there remains insufficient evidence regarding the optimal perioperative management of NOACs, particularly procedures with minor bleeding risks. Objective: This study aims to evaluate the safety and effectiveness of a simplified, standardized protocol for perioperative management of direct factor Xa inhibitors in patients, with AF undergoing procedures associated with minor bleeding risk. Methods: This multicenter, prospective single-arm registry study plans to enroll patients undergoing procedures with minor bleeding risk who were prescribed direct factor Xa inhibitors for AF. The procedures with minor bleeding risk will include gastrointestinal endoscopy for diagnostic purposes, selected dental procedures, and ocular surgery for cataracts or glaucoma. For apixaban, patients will withhold the last evening dose and resume either from the evening dose of the procedure day or the following morning, depending on the bleeding risk of the patient. For edoxaban or rivaroxaban, patients will withhold only a single dose on the procedure day. The primary outcome is the occurrence of major bleeding events within 30 days. Secondary outcomes include systemic thromboembolism, all-cause mortality, and a composite of major and clinically relevant non-major bleeding events. Conclusion: This study has the potential to generate evidence regarding the safety of perioperative management for patients, with AF undergoing procedures associated with minor bleeding risk. Trial Registration: Clinicaltrials.gov: NCT05801068.

Reversal or Repletion Treatment Strategies and Outcomes of Patients With Major Bleeding Events Managed in the Emergency Department: Large Real-Life Investigation in the Northwestern Healthcare District of Tuscany.

OBJECTIVE: To verify the incidence of bleeding events in patients on ongoing anticoagulant treatment in the real world and compare the results of different reversal or repletion strategies currently available for pharmacological treatment. METHODS: Patients managed in the emergency department (ED) with major bleeding events, on ongoing anticoagulation were stratified according to bleeding site and reversal or repletion therapy with andexanet alfa (ADX), idarucizumab (IDA), prothrombin complex concentrate (PCC), and vitamin K (Vit-K). ENDPOINT: Death at 30 days was compared in the subgroups with cerebral hemorrhage (CH) and gastrointestinal (GI) bleeding. RESULTS: Of the 809,397 visits in the years 2022-2023 at 6 EDs in the northwestern health district of Tuscany, 5372 patients with bleeding events were considered; 3740 were excluded due to minor bleeding or propensity score matching. Of the remaining 1632 patients with major bleeding, 548 on ongoing anticoagulation were enrolled; 334 received reversal or repletion agents. Patients with CH (n = 176) and GI bleeding (n = 108) represented the primary analysis cohorts in the study's strategic treatment assessment. Overall, 30-day survival of patients on ongoing aFXa treatment receiving on-label ADX versus off-label PCC showed a relative increase of 71%, while 30-day survival of patients on ongoing aFII receiving on-label IDA versus off-label PCC showed a relative increase of 30%; no substantial difference was found when comparing on-label PCC combined with Vit-K versus off-label Vit-K alone. Indeed, patients undergoing on-label ADX or IDA showed a statistically significant difference over off-label PCC (ADX vs. PCC: n = 15, events = 4, mean ± SD 82.50 ± 18.9, vs. 49, 13, 98.82 ± 27, respectively; analysis of variance [ANOVA] variance 8627; P < 0.001; posthoc test diff 32, 95% confidence interval: 28-35; P < 001; IDA vs. PCC: 20, 5, 32.29 ± 15.0 vs. 2, 1, 28.00 ± 0.0, respectively; ANOVA 1484; P < 0.001; posthoc test -29, -29 -29, respectively; P = n.d.). On-label PCC combined with Vit-K showed overall a slight statistically significant difference versus off-label Vit-K alone (52, 16, 100.58 ± 22.6 vs. 53, 11, 154.62 ± 29.8, respectively; ANOVA 310; P < 0.02; posthoc test 4, 0.7-7.2, respectively; P < 0.02). Data were confirmed in the group of patients with CH (ADX vs. PCC: n = 13, events = 3, mean ± SD 91.55 ± 18.6 vs. 78, 21, 108.91 ± 20.9, respectively; ANOVA variance 10,091, F = 261; P < 0.001; posthoc difference test 36, 95% confidence interval: 30-41; P < 0.001; IDA vs. PCC: 10, 2, 4.50 ± 2.5 vs. 78, 21, 108.91 ± 20.9, respectively; ANOVA 16,876,303, respectively; P < 0.001; posthoc test 41, 34-47, respectively; P < 0.001). On-label PCC combined with Vit-K showed an overall slight statistically significant difference compared with off-label Vit-K alone (P < 0.01 and P < 0.001 in the subgroups of CH and GI bleeding). CONCLUSIONS: Patients undergoing specific reversal therapy with on-label ADX or IDA, when treated with aFXa or aFII anticoagulants, respectively, showed statistically elevated differences in 30-day death compared with off-label repletion therapy with PCC. Overall, 30-day survival of patients on ongoing aFXa or aFII receiving on-label reversal therapy with ADX or IDA compared with off-label PCC repletion agents showed an increase of 71% and 30%, respectively.

Hemorrhagic Transformation in Noncardioembolic Acute Ischemic Stroke: MRI Analysis From PACIFIC-STROKE.

BACKGROUND: In the phase 2 PACIFIC-STROKE trial (Proper Dosing and Safety of the Oral FXIa Inhibitor BAY 2433334 in Patients Following Acute Noncardioembolic Stroke), asundexian, an oral factor XIa inhibitor, did not increase the risk of hemorrhagic transformation (HT). In this secondary analysis, we aimed to investigate the frequency, types, and risk factors of HT on brain magnetic resonance imaging (MRI). METHODS: This was a secondary analysis of the PACIFIC-STROKE trial. Patients with mild-to-moderate acute noncardioembolic ischemic stroke were randomly assigned to asundexian or placebo plus guideline-based antiplatelet therapy. Brain MRIs were required at baseline (≤120 hours after stroke onset) and at 26 weeks or end-of-study. HT was defined using the Heidelberg classification and classified as early HT (identified on baseline MRI) or late HT (new HT by 26 weeks) based on iron-sensitive sequences. Multivariable logistic regression models were used to test factors that are associated with early HT and late HT, respectively. RESULTS: Of 1745 patients with adequate baseline brain MRI (mean age, 67 years; mean National Institutes of Health Stroke Scale score, 2.8), early HT at baseline was detected in 497 (28.4%). Most were hemorrhagic infarctions (hemorrhagic infarction type 1: 15.2%; HI2: 12.7%) while a few were parenchymal hematomas (parenchymal hematoma type 1: 0.4%; parenchymal hematoma type 2: 0.2%). Early HT was more frequent with longer symptom onset-to-MRI interval. Male sex, diabetes, higher National Institutes of Health Stroke Scale large (>15 mm) infarct size, cortical involvement by infarct, higher number of acute infarcts, presence of chronic brain infarct, cerebral microbleed, and chronic cortical superficial siderosis were independently associated with early HT in the multivariable logistic regression model. Of 1507 with follow-up MRI, HT was seen in 642 (42.6%) overall, including 361 patients (23.9%) with late HT (new HT: 306; increased grade of baseline HT: 55). Higher National Institutes of Health Stroke Scale, large infarct size, cortical involvement of infarct, and higher number of acute infarcts predicted late HT. CONCLUSIONS: About 28% of patients with noncardioembolic stroke had early HT, and 24% had late HT detectable by MRI. Given the high frequency of HT on MRI, more research is needed on how it influences treatment decisions and outcomes.

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.

Comparison of Fixed Versus Weight-Based Prothrombin Complex Concentrate Dosing Strategies for Factor Xa Inhibitor Reversal.

Background: Our institution introduced fixed-dose prothrombin complex concentrate (PCC) to streamline order verification and medication administration. Previous studies using fixed-dose PCC for vitamin K antagonist reversal showed comparable efficacy to weight-based dosing. Objective: To compare fixed versus weight-based PCC dosing for reversal of Factor Xa Inhibitor (FXaI) effects. Methods: Retrospective cohort study conducted at a tertiary care academic medical center. Patients who received PCC to reverse the effects of apixaban or rivaroxaban were eligible. Subjects in the fixed-dose group (5000 units or 2000 units) were compared to weight-based PCC (50 units/kg). The primary outcome was time between order entry and medication administration. Secondary outcomes included: average PCC dose, postadministration procedures, achieved hemostasis, 30-day mortality, hospital length of stay, and adverse drug events. Results: 72 patients received fixed-dose PCC and 101 received weight-based PCC. Median time between order entry and administration was 4.5 min shorter in the fixed-dose group compared to weight-based (34.5 vs 39 min, P = .10). In patients who received fixed-dose, 79.2% achieved hemostasis versus 71.3% in the weight-based group (RR = 1.11, 95% CI = 0.94-1.32). There was no difference in the number of subsequent hemorrhage-related surgeries (29.2% vs 36.7%, RR = 0.80, 95% CI = 0.51-1.24) or mortality rate (26.4% vs 35.6%, RR = 0.73, 95% CI = 0.46-1.17). There were zero adverse drug events reported. Rates of thrombosis were 2.8% and < 1% (P = .57) in the fixed and weight-based groups, respectively. Conclusion and Relevance: The fixed-dosing strategy did not reduce time to PCC administration nor impact hemostasis or mortality. These data support that the fixed-dosing method is a viable option.

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.

A new model of portal vein thrombosis in rats with cirrhosis induced by partial portal vein ligation plus carbon tetrachloride and intervened with rivaroxaban.

BACKGROUND AND AIMS: Portal vein thrombosis (PVT) is a common complication of liver cirrhosis that can aggravate portal hypertension. However, there are features of both PVT and cirrhosis that are not recapitulated in most current animal models. In this study, we aimed to establish a stable animal model of PVT and cirrhosis, intervene with anticoagulant, and explore the related mechanism. METHODS: First, 49 male SD rats received partial portal vein ligation (PPVL), and 44 survival rats were divided into 6 groups: PPVL control group; 4-week, 6 -week, 8-week, and 10-week model group; and the rivaroxaban (RIVA)-treated group. The rats were intoxicated with or without carbon tetrachloride (CCl4) for 4-10 weeks. Seven normal rats were used as the normal controls. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and parameters for blood coagulation were all assayed with kits. Liver inflammation, collagen deposition and hydroxyproline (Hyp) levels were also measured. The extrahepatic macro-PVT was observed via portal vein HE staining, etc. The intrahepatic microthrombi was stained via fibrin immunohistochemistry. The portal blood flow velocity (PBFV) and diameter were detected via color Doppler ultrasound. Vascular endothelial injury was evaluated by von Willebrand Factor (vWF) immunofluorescence. Fibrinolytic activity was estimated by western blot analysis of fibrin and plasminogen activator inhibitor-1 (PAI-1). RESULTS: After PPVL surgery and 10 weeks of CCl4 intoxication, a rat model that exhibited characteristics of both cirrhosis and extra and intrahepatic thrombi was established. In cirrhotic rats with PVT, the PBFV decreased, both factors of pro- and anti-coagulation decreased, but with relative hypercoagulable state, vascular endothelial injured, and fibrinolytic activity decreased. RIVA-treated rats had improved coagulation function, increased PBFV and attenuated thrombi. This effect was related to the improvements in endothelial injury and fibrinolytic activity. CONCLUSIONS: A new rat model of PVT with cirrhosis was established through partial portal vein ligation plus CCl4 intoxication, with the characteristics of macrothrombi at portal veins and microthrombi in hepatic sinusoids, as well as liver cirrhosis. Rivaroxaban could attenuate PVT in cirrhosis in the model rats. The underlying mechanisms of PVT formation in the rat model and pharmacological action of rivaroxaban are related to the regulation of portal blood flow, coagulant factors, and vascular endothelial cell function.