Performance of direct oral anticoagulant (DOAC) testing by hemostasis laboratories: The Australasian/Asia-Pacific experience

INTRODUCTION

Direct oral anticoagulants (DOACs) reflect anticoagulation agents given to treat or prevent thrombosis, having largely replaced vitamin K antagonists (VKAs) such as warfarin. DOACs are given in fixed daily doses and generally do not need monitoring. However, there may be a variety of reasons that justify measurement of plasma DOAC levels in individual patients.

METHODS

We report updated findings for DOAC testing in our geographic region, using recent data from the RCPAQAP, an international external quality assessment (EQA) program, currently with some 40-60 participants in each of the different DOAC (rivaroxaban, apixaban, dabigatran) modules, to assess laboratory performance in this area. Data has been assessed for the past 5 years (2019-2023 inclusive), with 20 samples each per DOAC.

RESULTS

Data shows a limited repertoire of assays in use, and mostly consistency in reported numerical values when assessing proficiency samples. Available assays mostly comprised reagents from four manufacturing suppliers. There was good consistency across what participants identified as 'DOAC detected', but some variability when participants attempted to grade DOAC levels as low vs moderate vs high. Inter-laboratory/method coefficient of variation (CVs) were generally <15% for each DOAC, when present at >100 ng/mL.

CONCLUSION

We hope our findings, reflecting on mostly consistent reporting of DOAC levels and interpretation provides reassurance for clinicians requesting these measurements, and helps support their implementation in regions where there is a paucity of test availability.

Quantitative Benefit-Risk Evaluation of Rivaroxaban in Patients After Peripheral Arterial Revascularization: The VOYAGER PAD Trial

BACKGROUND

The VOYAGER PAD (Efficacy and Safety of Rivaroxaban in Reducing the Risk of Major Thrombotic Vascular Events in Subjects With Symptomatic Peripheral Artery Disease Undergoing Peripheral Revascularization Procedures of the Lower Extremities) trial compared rivaroxaban (2.5 mg twice a day) plus aspirin with aspirin alone in patients with symptomatic peripheral artery disease requiring endovascular or surgical limb revascularization, with 50% receiving clopidogrel background therapy. The New Drug Indication application includes benefit-risk assessments using clinical judgment to balance benefits against risks. During its review, the US Food and Drug Administration requested additional quantitative benefit-risk analyses with formal weighting approaches.

METHODS AND RESULTS

Benefits and risks were assessed using rate differences between treatment groups (unweighted analysis). To account for clinical importance of the end points, a multi-criteria decision analysis was conducted using health state utility values as weights. Monte Carlo simulations incorporated statistical uncertainties of the event rates and utility weights. Intent-to-treat and on-treatment analyses were conducted. For unweighted intent-to-treat analyses, rivaroxaban plus aspirin would result in 120 (95% CI, -208 to -32) fewer events of the primary composite end point (per 10 000 patient-years) compared with aspirin alone. Rivaroxaban caused an excess of 40 (95% CI, 8-72) Thrombolysis in Myocardial Infarction major bleeding events, which was largely driven by nonfatal, nonintracranial hemorrhage Thrombolysis in Myocardial Infarction major bleeding events. For weighted analyses, rivaroxaban resulted in the utility equivalent of 13.7 (95% CI, -85.3 to 52.6) and 68.1 (95% CI, 7.9-135.7) fewer deaths per 10 000 patient-years (intent-to-treat and on-treatment, respectively), corresponding to probabilities of 64.4% and 98.7%, respectively, that benefits outweigh risks favoring rivaroxaban per Monte Carlo simulation.

CONCLUSIONS

These analyses show a favorable benefit-risk profile of rivaroxaban therapy in the VOYAGER PAD trial, with findings generally consistent between the unweighted and weighted approaches.

Case report: Severe hepatopathy following rivaroxaban administration in a dog

Rivaroxaban, a specific factor Xa inhibitor and commonly utilized anticoagulant, has been known to cause hepatotoxicity and liver failure in humans. Although rivaroxaban is frequently used in veterinary medicine, hepatotoxicity has not been previously reported in dogs. The current case report describes a dog that developed severe hepatopathy following rivaroxaban administration for a large right pulmonary artery thrombus. An estimated 6-year-old spayed female mixed-breed dog developed anorexia and lethargy 9 days after rivaroxaban administration began. Subsequent labwork revealed severe hepatocellular hepatopathy, and rivaroxaban was discontinued. Additional diagnostics did not reveal an underlying etiology, although hepatic cytology could be consistent with a toxic injury. The hepatopathy and clinical signs improved after rivaroxaban was discontinued. The time to onset, type of hepatopathy, and time to resolution were all similar to those reported for human cases. This case provides precedence to advocate for improved and closer monitoring of dogs receiving factor Xa inhibitors. In cases of suspected hepatotoxicity with no other identifiable cause, a risk-benefit analysis should be performed, and discontinuation of rivaroxaban administration or alternative anticoagulant medications should be considered.

Efficacy and Safety of Combination Therapy with Low-Dose Rivaroxaban in Patients with Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objectives: To review the evidence on the effectiveness and safety of low-dose-rivaroxaban 2.5 mg twice daily (LDR) in patients with coronary artery disease (CAD) and/or peripheral artery disease (PAD) taking antiplatelets. Methods: We performed a systematic review and meta-analysis of randomized controlled trials (RCTs). Efficacy endpoints were cardiovascular events (CVEs), myocardial infarction, stroke, all-cause, and cardiovascular death. Any, major, fatal bleeding, and intracranial hemorrhage (ICH) were safety endpoints. Numbers needed to treat (NNT), and numbers needed to harm (NNH) were also calculated. Results: Seven RCTs were included with 45,836 patients: 34,276 with CAD and 11,560 with PAD. Overall, 4247 CVEs and 3082 bleedings were registered. LDR in association with either any antiplatelet drug or aspirin (ASA) alone reduced the risk of CVEs (hazard ratio [HR] 0.86, 95% confidence interval [95%CI] 0.78-0.94) and ischemic stroke (HR 0.68, 95%CI 0.55-0.84). LDR + ASA increased the risk of major bleeding (HR 1.71, 95%CI 1.38-2.11) but no excess of fatal bleeding or ICH was found. The NNT to prevent one CVE for LDR + ASA was 63 (43-103) and the NNH to cause major bleeding was 107 (77-193). Conclusions: The combination of LDR with either antiplatelet drugs or low-dose aspirin reduces CVEs and ischemic stroke in patients with CAD/PAD. There was an increased risk of major bleeding but no excess of fatal or ICH was found. LDR seems to have a favorable net clinical benefit compared to ASA treatment alone.

Comparison of the Efficacy and Safety of Rivaroxaban and Low Molecular Heparin in Preventing Venous Thromboembolism in Inpatient Cancer Patients

BACKGROUND

There are few studies on using rivaroxaban and low molecular heparin (LMWH) to prevent venous thromboembolism (VTE) in hospitalized cancer patients.

OBJECTIVE

We conducted a retrospective study to evaluate the efficacy and safety of rivaroxaban versus LMWH for the primary prevention of VTE in inpatient cancer patients.

METHODS

Information on patients was collected through 6-month follow-up and medical record inquiries. Clinical outcomes included VTE, total bleeding, thrombosis, major bleeding, minor bleeding, all-cause death, and a composite endpoint of bleeding, thrombosis, and death.

RESULTS

A total of 602 hospitalized cancer patients were included in this study. During 6 months of follow-up, there were 26 VTE events (8.6%), 42 total bleeding events (7.0%), 62 all-cause deaths (10.3%), and 140 composite endpoints (23.3%). After adjusting for various confounding factors, there were no significant differences between the rivaroxaban and LMWH for VTE events (OR = 0.851, 95% CI [0.387-1.872], P=0.688), total bleeding (OR = 1.690, 95% CI [0.768-3.719], P = 0.192], thrombosis events (OR = 0.919, 95% CI [0.520-1.624], P = 0.772], major bleeding (OR = 0.276, 95% CI [0.037-2.059], P = 0.209), all-cause death (OR = 0.994, 95% CI [0.492-2.009], P = 0.987), and composite endpoints (OR = 0.994, 95% CI [0.492-2.009], P = 0.987), while minor bleeding (OR = 3.661 95% CI [1.000-7.083], P = 0.050) was significantly higher in the rivaroxaban than in the LMWH.

CONCLUSIONS AND RELEVANCE

In thromboprophylaxis in inpatient cancer patients, rivaroxaban has a similar rate of VTE and bleeding events as LMWH. Our results may provide a reference for the clinical use of rivaroxaban to prevent VTE in hospitalized cancer patients.

Bioequivalence Study of Capsules versus Film Tablets Containing Rivaroxaban in Healthy Caucasian Subjects under Fasting and Fed Conditions

The bioequivalence (BE) of orally administered capsules versus film tablets containing 20  and 10 mg of rivaroxaban was assessed in 2 single-dose, open-label, randomized 2-way crossover trials with a washout period of at least 1 week. The study for the 10 mg strength was conducted under fasting conditions (n = 68) and the study for the 20 mg strength under fed conditions (n = 52). Blood samples were collected over a 36-hour period and concentrations were assayed using a liquid chromatography tandem mass spectrometry method. Pharmacokinetic (PK) evaluation was performed with the program Phoenix WinNonlin, for non-compartmental assessment of data. After administration of 10 mg rivaroxaban under fasting conditions, mean Area Under the time - concentration Curve until the last blood sampling point (AUCt ), Area Under the time - concentration Curve until infinity (AUC∞ ), and maximum plasma concentration (Cmax ) were comparable (972 ng/mL*h, 1048 ng/mL*h, and 111 ng/mL, respectively, for the test and 1013 ng/mL*h, 1070 ng/mL*h and 130 ng/mL, respectively, for the reference formulation). Mean AUCt , AUC∞ , and Cmax were also comparable under fed conditions after administration of 20 mg rivaroxaban (2145 ng/mL*h, 2198 ng/mL*h and 275 ng/mL, respectively, for the test and 1856 ng/mL*h, 1916 ng/mL*h and 240 ng/mL, respectively, for the reference formulation). The 90% confidence intervals for all PK parameters were within the acceptance range of 80%-125%, suggesting BE between the generic product and the innovator product in healthy Caucasian male subjects. A clinically relevant difference in the tolerability and safety of the treatments was not detected. Study results indicated that the capsule formulations were bioequivalent with the film tablet formulations.

Comparative Safety and Effectiveness of Warfarin or Rivaroxaban Versus Apixaban in Patients With Advanced CKD and Atrial Fibrillation: Nationwide US Cohort Study

RATIONALE & OBJECTIVE

Head-to-head data comparing the effectiveness and safety of oral anticoagulants in patients with atrial fibrillation (AF) and advanced chronic kidney disease (CKD) are lacking. We compared the safety and effectiveness of warfarin or rivaroxaban versus apixaban in patients with AF and non-dialysis-dependent CKD stage 4/5.

STUDY DESIGN

Propensity score-matched cohort study.

SETTING & PARTICIPANTS

2 nationwide US claims databases, Medicare and Optum's deidentified Clinformatics Data Mart Database, were searched for the interval from January 1, 2013, through March 31, 2022, for patients with nonvalvular AF and CKD stage 4/5 who initiated warfarin versus apixaban (matched cohort, n=12,488) and rivaroxaban versus apixaban (matched cohort, n = 5,720).

EXPOSURES

Warfarin, rivaroxaban, or apixaban.

OUTCOMES

Primary outcomes included major bleeding and ischemic stroke. Secondary outcomes included all-cause mortality, major gastrointestinal bleeding, and intracranial bleeding.

ANALYTICAL APPROACH

Cox regression was used to estimate HRs, and 1:1 propensity-score matching was used to adjust for 80 potential confounders.

RESULTS

Compared with apixaban, warfarin initiation was associated with a higher rate of major bleeding (HR, 1.85; 95% CI, 1.59-2.15), including major gastrointestinal bleeding (1.86; 1.53-2.25) and intracranial bleeding (2.15; 1.42-3.25). Compared with apixaban, rivaroxaban was also associated with a higher rate of major bleeding (1.69; 1.33-2.15). All-cause mortality was similar for warfarin (1.08; 0.98-1.18) and rivaroxaban (0.94; 0.81-1.10) versus apixaban. Furthermore, no statistically significant differences for ischemic stroke were observed for warfarin (1.14; 0.83-1.57) or rivaroxaban (0.71; 0.40-1.24) versus apixaban, but the CIs were wide. Similar results were observed for warfarin versus apixaban in the positive control cohort of patients with CKD stage 3, consistent with randomized trial findings.

LIMITATIONS

Few ischemic stroke events, potential residual confounding.

CONCLUSIONS

In patients with AF and advanced CKD, rivaroxaban and warfarin were associated with higher rates of major bleeding compared with apixaban, suggesting a superior safety profile for apixaban in this high-risk population.

PLAIN-LANGUAGE SUMMARY

Different anticoagulants have been shown to reduce the risk of stroke in patients with atrial fibrillation, such as warfarin and direct oral anticoagulants like apixaban and rivaroxaban. Unfortunately, the large-scale randomized trials that compared direct anticoagulants versus warfarin excluded patients with advanced chronic kidney disease. Therefore, the comparative safety and effectiveness of warfarin, apixaban, and rivaroxaban are uncertain in this population. In this study, we used administrative claims data from the United States to answer this question. We found that warfarin and rivaroxaban were associated with increased risks of major bleeding compared with apixaban. There were few stroke events, with no major differences among the 3 drugs in the risk of stroke. In conclusion, this study suggests that apixaban has a better safety profile than warfarin and rivaroxaban.

Direct oral anticoagulants compared with warfarin in patients with left ventricular thrombus: a cohort study from China

Background

Current guidelines recommend vitamin K antagonist (VKA) for left ventricular (LV) thrombus. This study aimed to compare the effectiveness and safety of direct oral anticoagulant (DOAC) and warfarin in Chinese patients with LV thrombus.

Methods

Patients with LV thrombus admitted to Beijing Anzhen Hospital of Capital Medical University between January 2018 and January 2022, were enrolled in this cohort study. The primary endpoint was defined as thrombus resolution within 90 days. The secondary endpoints included thrombus resolution within 180 days, major bleeding events, and minor bleeding events. All patients were followed up for at least 90 days after diagnosis of LV thrombus. Patients were divided into the VKA and DOAC groups according to the anticoagulants. Differences in clinical endpoint events between the two groups were compared.

Results

This study included 129 and 111 patients in the VKA and DOAC groups, respectively. After adjusting for gender and smoking status, no significant difference was observed in thrombus resolution within 90 days between the VKA and DOAC groups. Additionally, there was no difference between the two groups in the secondary endpoints of thrombus resolution within 180 days, major bleeding, and minor bleeding. In subgroup analysis, rivaroxaban and dabigatran did not show significant differences in primary and secondary endpoints.

Conclusions

This study showed no significant difference in thrombus resolution between DOAC and warfarin. DOAC might be an alternative to warfarin for the treatment of LV thrombus. However, further large prospective studies are required to explore the efficacy and safety of DOAC in patients with LV thrombus.

Twice-daily rivaroxaban after percutaneous left atrial appendage closure for atrial fibrillation

Background and aim: Rivaroxaban is an emerging oral anticoagulant for postoperative anticoagulation after percutaneous left atrial appendage closure (LAAC). Because a once-daily dosing regimen of rivaroxaban causes fluctuations in the drug plasma concentration, we studied the feasibility and safety of twice-daily rivaroxaban as a postoperative anticoagulation regimen for patients with atrial fibrillation (AF) undergoing LAAC. Methods: This study involved patients with AF who underwent LAAC and took rivaroxaban postoperatively. A total of 326 patients who received a standard total dose (15 or 20 mg) of rivaroxaban based on their creatinine clearance rate were divided into the twice-daily (BID) rivaroxaban group (n = 208) and once-daily (QD) rivaroxaban group (n = 118) according to their anticoagulation strategy. Transesophageal echocardiography was recommended at 3-6 months postoperatively to check for device-related thrombosis (DRT). Clinical outcomes were evaluated during postoperative anticoagulation. Results: The median CHA2DS2-VASc score (4 [3, 5] vs. 4 [3, 5], p = 0.28) and HAS-BLED score (2 [2, 3] vs. 2 [2, 3], p = 0.48) were not significantly different between the groups. During the anticoagulation period (4.1 ± 0.7 vs. 4.1 ± 0.9 months, p = 0.58), 148 (71.2%) patients in the BID group and 75 (63.6%) in the QD group underwent follow-up transesophageal echocardiography. There were no statistically significant differences between the two groups in terms of DRT (1.4% vs. 2.7%, p = 0.60), minor bleeding (8.2% vs. 11.0%, p = 0.39), thromboembolic events (1.0% vs. 0.8%, p = 1.00), major bleeding (0.5% vs. 0.8%, p = 1.00), or death. Conclusion: A short course of twice-daily rivaroxaban following LAAC is a feasible alternative regimen with a low rate of major bleeding events, DRT, and thromboembolic events for patients with AF.

Direct oral anticoagulants compared to warfarin in long-term management of cerebral venous thrombosis: A comprehensive meta-analysis

Objectives

We compared the safety and efficacy of direct oral anticoagulants (DOACs) with those of warfarin in the long-term (≥6 months) treatment of cerebral venous thrombosis (CVT).

Methods

We searched electronic databases up to November 2023 to compare the use of DOACs and warfarin in CVT management. Modified Rankin scores (mRS), new intracranial hemorrhage, all-cause mortality, recurrence and nonrecanalisation events were used to assess outcome. RevMan v5.4 software and the Cochran-Mantel-Haenszel method were utilized to analyse data.

Results

A total of 25 studies involving 2301 patients were identified as having treated CVT with either DOACs or warfarin. Good long-term mRS scores 0-2 (risk ratio [RR] = 1.01, 95% CI = 0.98-1.03; p = 0.61), new intracranial hemorrhage (RR = 1.00, 95% CI = 0.48-2.08; p = 0.99), all-cause mortality (RR = 1.00, 95% CI = 0.50-1.98; p = 0.99), nonrecanalisation (RR = 0.95, 95% CI = 0.77-1.18; p = 0.65) and recurrence venous thrombosis events (RR = 0.63, 95% CI = 0.33-1.22; p = 0.17) were similar between the two treatment arms. Subgroup analysis found recurrence of venous thrombosis was lower in the rivaroxaban group compared to warfarin (2.2% vs. 8.5%, RR = 0.33, 95% CI = 0.11-0.98; p = 0.05).

Conclusion

DOACs and warfarin provide comparable long-term safety and efficacy profiles. DOACs may be preferred over warfarin due to their ease of clinical management.

Comparative analysis of andexanet alfa and prothrombin complex concentrate in reversing anticoagulation by rivaroxaban ex vivo

BACKGROUND

The comparative effectiveness of the specific antidote andexanet alfa vs the nonspecific therapy four-factor prothrombin complex concentrates (4F-PCCs) as reversal agents for direct factor Xa (FXa) inhibitors in severely bleeding patients is unclear. We hypothesised that specific reversal using andexanet alfa would be more effective than a high dose of PCC (50 IU kg-1) for reversing the FXa inhibitor rivaroxaban.

METHODS

The reversal potential of andexanet alfa, various 4F-PCCs, and activated PCC was investigated ex vivo in human blood anticoagulated with rivaroxaban (37.5, 75, 150, and 300 ng ml-1) using a panel of coagulation parameters, including conventional coagulation assays, thrombin generation, and a newly developed viscoelastometric device. We simulated in vivo conditions of coagulation activation and fibrin formation using flow chamber experiments of thrombogenicity potential under arterial flow conditions.

RESULTS

The 4F-PCCs normalised clotting profiles only at low rivaroxaban concentrations, whereas andexanet alfa and activated PCC significantly shortened clotting time at all rivaroxaban concentrations. Only andexanet alfa restored thrombin generation to baseline. Flow chamber results showed that various 4F-PCCs concentration-dependently restored clot formation.

CONCLUSIONS

In contrast to thrombin generation measurements, haemostatic reversal of rivaroxaban using high-dose 4F-PCCs exhibited similar efficacy as andexanet alfa in flow chamber experiments. The haemostatic effects of 4F-PCCs and andexanet alfa in the context of bleeding patients taking FXa inhibitors requires further study.

Andexanet alfa or prothrombin complex concentrate for acute reversal of oral factor Xa inhibitors: monitoring of antidote effects

This study in vitro comprehensively assessed reversal of the anticoagulant effects of rivaroxaban, an oral factor Xa inhibitor, using andexanet alfa and various prothrombin complex concentrate (PCC) products in a battery of tests. In static coagulation assays, andexanet alpha outperformed PCCs except for activated PCC being more effective in standard coagulation times. However, in a flow chamber model mimicking arterial shear, both andexanet alpha and high-concentration PCC restored fibrin formation, but not platelet adhesion. In the Russell's viper venom test and anti-Xa assay, only andexanet alpha could be tested for efficacy. The antidote effects of andexanet alpha and PCCs in restoring coagulation can be qualitatively or selectively demonstrated using in vitro coagulation tests.

Efficacy and safety of factor Xa inhibitors in low body weight patients

STUDY OBJECTIVE

The purpose of this study is to provide evidence for the safety and efficacy of factor Xa inhibitors in patients with a weight ≤60 kg or BMI < 18.5 kg/m2 .

DESIGN

Multicenter, retrospective, cohort study.

SETTING

Twenty-two Ascension Health hospitals.

PATIENTS

Low-body-weight adult patients (weight ≤ 60 kg or BMI < 18.5 kg/m2 ) receiving treatment for atrial fibrillation or venous thromboembolism.

INTERVENTION

Factor Xa inhibitors (apixaban or rivaroxaban) or warfarin.

MEASUREMENTS AND MAIN RESULTS

This study included 2538 patients between the factor Xa inhibitors (n = 1695) and warfarin (n = 843) groups with a mean weight of 53.5 ± 5.5 kg and BMI of 20.7 ± 3.1 kg/m2 . No significant difference in time to major bleeding was noted after controlling for potential confounders (HR 1.03, 95% CI 0.70-1.53, p = 0.87); similar results were seen following propensity score matching. Thromboembolism (5.3% vs. 6.2%, p = 0.38), composite major + clinically relevant nonmajor bleeding (9.8% vs. 11.5%, p = 0.18), and all-cause mortality (10.7% vs. 12.8%, p = 0.12) were similar between patients receiving factor Xa inhibitors versus warfarin.

CONCLUSION

No differences in safety or effectiveness were noted between factor Xa inhibitors versus warfarin. These findings provide encouraging evidence to support the use of factor Xa inhibitors in low-body-weight patients.

Partial Segmental Thrombosis of the Corpus Cavernosum Associated With Inappropriate Sildenafil Use

The case presented is of a 39-year-old male with severe right groin pain and perineal pain the morning after sexual intercourse with the use of sildenafil without a diagnosis of erectile dysfunction. Partial segmental thrombosis of the corpus cavernosum (PSTCC) was diagnosed using magnetic resonance imaging and treated with direct oral anticoagulation without complications. Sildenafil use has been noted as an inciting factor for PSTCC in only two other cases of less than 60 cases reported in the literature and has even been used successfully as a component of therapeutic management of PSTCC in another previous case.

Factors associated with disease progression in patients with atrial fibrillation and heart failure anticoagulated with rivaroxaban

BACKGROUND

Patients with atrial fibrillation (AF) and heart failure (HF) have a high risk of thromboembolism and other outcomes and anticoagulation is recommended.

HYPOTHESIS

This study was aimed to explore the risk factors associated with HF worsening in patients with AF and HF taking rivaroxaban in Spain.

METHODS

Multicenter, prospective, observational study that included adults with AF and chronic HF, receiving rivaroxaban ≥4 months before entering. HF worsening was defined as first hospitalization or emergency visit because of HF exacerbation.

RESULTS

A total of 672 patients from 71 Spanish centers were recruited, of whom 658 (97.9%) were included in the safety analysis and 552 (82.1%) in the per protocol analysis. At baseline, mean age was 73.7 ± 10.9 years, 64.9% were male, CHA2 DS2 -VASc was 4.1 ± 1.5, HAS-BLED was 1.6 ± 0.9% and 51.3% had HF with preserved ejection fraction. After 24 months of follow-up, 24.9% of patients developed HF worsening, 11.6% died, 2.9% had a thromboembolic event, 3.1% a major bleeding, 0.5% an intracranial bleeding and no patient had a fatal hemorrhage. Older age, the history of chronic obstructive pulmonary disease, the previous use of vitamin K antagonists, and restrictive or infiltrative cardiomyopathies, were independently associated with HF worsening. Only 6.9% of patients permanently discontinued rivaroxaban treatment.

CONCLUSIONS

Approximately one out of four patients with HF and AF treated with rivaroxaban developed a HF worsening episode after 2 years of follow-up. The identification of those factors that increase the risk of HF worsening could be helpful in the comprehensive management of this population.

Assessing the Safety and Efficacy of Rivaroxaban for Stroke Prevention in Patients With Atrial Fibrillation: A Systemic Review and Meta-Analysis

An effective anticoagulation therapy is required for patients with atrial fibrillation because it presents a significant risk of stroke. The current study evaluates the relative safety as well as efficacy of rivaroxaban in patients who are diagnosed with atrial fibrillation. A thorough literature review of relevant databases was conducted, focusing on academic and clinical studies that were published from 2017 onward. Inclusion criteria comprised randomized controlled trials and other observational studies comparing the incidence of stroke and the safety index of rivaroxaban in atrial fibrillation. We followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) for data overview reporting and overview. A total of 21 studies were selected based on the inclusion criteria. A total of 19/21 studies advocated the adoption of rivaroxaban for minimizing stroke incidence. Rivaroxaban also showed superiority in achieving the therapeutic objectives, i.e., reduction in the incidence of stroke. The results for rivaroxaban against warfarin showed an improved safety index and effectiveness of rivaroxaban. The total effect size for the analysis was calculated to be Z=2.62 (p-value=0.009). The individual effect of all studies favored the "rivaroxaban" group. The heterogeneity in the study was as follows: tau2=0.10; chi2=110.10, df=6; I2=95%. The second analysis for risk reduction and incidence of stroke after rivaroxaban therapy also showed a bias towards rivaroxaban therapy. The combined effect for the analysis was found to be as follows: HR=0.73 ((95% CI: 0.50, 1.07). The total effect was calculated to be Z=1.61 (p-value= 0.10). The heterogeneity was found to be as follows: tau2= 0.20, chi2=89.97, df=6, I2=93%. Standard dosing of rivaroxaban emerges as a preferred strategy for stroke prevention, balancing efficacy and safety. Clinical decision-making should consider individual patient characteristics and future research should delve into specific subpopulations and long-term outcomes to further refine treatment guidelines.

Effect of a High-Fat Diet on the Pharmacokinetics and Safety of Rivaroxaban in Healthy Chinese Subjects

The effects of food on the pharmacokinetics (PKs) and safety of 10-mg rivaroxaban tablets in healthy Chinese subjects were investigated from 1 bioequivalence trial. The bioequivalence trial was designed as randomized, open-label, 2-sequence, 4-period crossover under both fasted and fed conditions. A total of 56 healthy subjects were enrolled, 62.5% were male. These subjects received a single oral 10-mg dose of rivaroxaban with a 7-day washout between 4 periods. Serial PK samples were collected and plasma concentrations were analyzed using validated high-performance liquid chromatography-mass spectrometry. Pharmacokinetic parameters were calculated by noncompartmental methods. The BE module of WinNonLin was used for statistical analysis of the maximum concentration (Cmax ), the area under the concentration-time curve from zero to the final measurable concentration (AUC0-t ), and the area under the concentration-time curve from time zero to infinity (AUC0-∞ ) of rivaroxaban in plasma. Compared with the fasted state, the Cmax , AUC0-t , and AUC0-∞ of rivaroxaban significantly increased by 47%, 28%, and 26%, respectively, with oral administration of rivaroxaban 10 mg in the fed state. The incidence of adverse events (AEs) was similar between the fasted and fed states, and no serious AEs were observed. Food significantly increased the exposure to rivaroxaban 10 mg in Chinese subjects.

Real-World Reversal of Factor Xa Inhibition in the Setting of Major Life-Threatening Bleeding or Urgent Surgery

Background: Management of major life-threatening bleeding with factor Xa (FXa) inhibition poses complex challenges involving novel direct reversal agents competing with non-specific preexisting strategies. The recent availability of andexanet alfa (AA) led to a health-system guideline incorporating its use alongside the most commonly used historic agent, four-factor prothrombin complex concentrate (4F-PCC). Objectives: The objective was to characterize the use and efficacy of AA and 4F-PCC for reversal of FXa inhibition after implementation of the health-system guideline. Methods: This multi-hospital, retrospective cohort study included patients aged >18 years administered either AA or 4F-PCC between October 2018 to June 2020 with the indication for urgent reversal of FXa inhibitor-induced coagulopathy. The primary outcome assessed hemostatic efficacy between treatment groups. Secondary outcomes evaluated adjunct blood product administration, incidence of repeat pharmacologic reversal, incidence of thromboembolism, intensive care unit and hospital length of stays, and in-hospital mortality. Results: Eighty-five patients were included; 33 patients received AA and 52 patients received 4F-PCC. Effective hemostasis was achieved at similar rates in both treatment groups (84.8% vs 76.9%; P = .373). Thrombotic events occurring during the observed hospitalization were more frequent among the AA treated group (18% vs 3.8%, P = .027). No differences were observed for other secondary outcomes. Conclusion: Guideline use resulted in similar rates of effective hemostasis with a higher incidence of VTE in patients receiving AA. Further exploration with a larger, prospective study to evaluate these findings is warranted.

The Effect of Rivaroxaban in the Complementary Therapy of Sudden Sensorineural Hearing Loss

Background

Due to the importance of sudden sensorineural hearing loss (SSNHL) and the possible role of blood coagulation in its mechanism and the likely therapeutic effect of anticoagulants and also the lack of studies in this field, this study aimed to evaluate the effect of rivaroxaban (RXA) in the treatment of this disease.

Materials and Methods

The present double-blind randomized clinical trial study was performed on 34 patients with SSNHL. Patients were randomly divided into two groups. In the first group, in addition to corticosteroid therapy (CST), RXA 10 mg tablets were used daily for 10 days (RXA group), and in the second group, only CST (CST group) treatment was prescribed. Hearing recovery was then assessed and recorded according to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) criteria.

Results

This study showed that the grade of hearing recovery in the RXA group (58.8%) was higher than the CST group (47.1%), but this difference was not significant (P value >0.05). Also, RXA treatment increased the odds of hearing recovery, and this difference was not statistically significant (odd ratio (95% confidence interval)(OR (95% CI): 2.327 (0.180-18.082); P value = 0.518). In contrast, delay to treatment, more increased PTA (pure tone average (PTA)), and having vertigo reduced the odds of hearing recovery by 0.138-, 0.019-, and 0.069-fold, respectively (P value <0.05).

Conclusion

According to the results of this study, although the percentage of hearing recovery was higher in the RXA group, in general, the results of the two treatments were not significantly different.

Non-vitamin-K-antagonist oral anticoagulants (NOACs) after acute myocardial infarction: a network meta-analysis

BACKGROUND

Balancing the risk of bleeding and thrombosis after acute myocardial infarction (AMI) is challenging, and the optimal antithrombotic therapy remains uncertain. The potential of non-vitamin K antagonist oral anticoagulants (NOACs) to prevent ischaemic cardiovascular events is promising, but the evidence remains limited.

OBJECTIVES

To evaluate the efficacy and safety of non-vitamin-K-antagonist oral anticoagulants (NOACs) in addition to background antiplatelet therapy, compared with placebo, antiplatelet therapy, or both, after acute myocardial infarction (AMI) in people without an indication for anticoagulation (i.e. atrial fibrillation or venous thromboembolism).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, the Conference Proceedings Citation Index - Science, and two clinical trial registers in September 2022 with no language restrictions. We checked the reference lists of included studies for any additional trials.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) that evaluated NOACs plus antiplatelet therapy versus placebo, antiplatelet therapy, or both, in people without an indication for anticoagulation after an AMI.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked the results of searches to identify relevant studies, assessed each included study, and extracted study data. We conducted random-effects pairwise analyses using Review Manager Web, and network meta-analysis using the R package 'netmeta'. We ranked competing treatments by P scores, which are derived from the P values of all pairwise comparisons and allow ranking of treatments on a continuous 0-to-1 scale.

MAIN RESULTS

We identified seven eligible RCTs, including an ongoing trial that we could not include in the analysis. Of the six RCTs involving 33,039 participants, three RCTs compared rivaroxaban with placebo, two RCTs compared apixaban with placebo, and one RCT compared dabigatran with placebo. All participants in the six RCTs received concomitant antiplatelet therapy. The available evidence suggests that rivaroxaban compared with placebo reduces the rate of all-cause mortality (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.69 to 0.98; number needed to treat for an additional beneficial outcome (NNTB) 250; 3 studies, 21,870 participants; high certainty) and probably reduces cardiovascular mortality (RR 0.83, 95% CI 0.69 to 1.01; NNTB 250; 3 studies, 21,870 participants; moderate certainty). There is probably little or no difference between apixaban and placebo in all-cause mortality (RR 1.09, 95% CI 0.88 to 1.35; number needed to treat for an additional harmful outcome (NNTH) 334; 2 studies, 8638 participants; moderate certainty) and cardiovascular mortality (RR 0.99, 95% CI 0.77 to 1.27; number needed to treat not applicable; 2 studies, 8638 participants; moderate certainty). Dabigatran may reduce the rate of all-cause mortality compared with placebo (RR 0.57, 95% CI 0.31 to 1.06; NNTB 63; 1 study, 1861 participants; low certainty). Dabigatran compared with placebo may have little or no effect on cardiovascular mortality, although the point estimate suggests benefit (RR 0.72, 95% CI 0.34 to 1.52; NNTB 143; 1 study, 1861 participants; low certainty). Two of the investigated NOACs were associated with an increased risk of major bleeding compared to placebo: apixaban (RR 2.41, 95% CI 1.44 to 4.06; NNTH 143; 2 studies, 8544 participants; high certainty) and rivaroxaban (RR 3.31, 95% CI 1.12 to 9.77; NNTH 125; 3 studies, 21,870 participants; high certainty). There may be little or no difference between dabigatran and placebo in the risk of major bleeding (RR 1.74, 95% CI 0.22 to 14.12; NNTH 500; 1 study, 1861 participants; low certainty). The results of the network meta-analysis were inconclusive between the different NOACs at all individual doses for all primary outcomes. However, low-certainty evidence suggests that apixaban (combined dose) may be less effective than rivaroxaban and dabigatran for preventing all-cause mortality after AMI in people without an indication for anticoagulation.

AUTHORS' CONCLUSIONS

Compared with placebo, rivaroxaban reduces all-cause mortality and probably reduces cardiovascular mortality after AMI in people without an indication for anticoagulation. Dabigatran may reduce the rate of all-cause mortality and may have little or no effect on cardiovascular mortality. There is probably no meaningful difference in the rate of all-cause mortality and cardiovascular mortality between apixaban and placebo. Moreover, we found no meaningful benefit in efficacy outcomes for specific therapy doses of any investigated NOACs following AMI in people without an indication for anticoagulation. Evidence from the included studies suggests that rivaroxaban and apixaban increase the risk of major bleeding compared with placebo. There may be little or no difference between dabigatran and placebo in the risk of major bleeding. Network meta-analysis did not show any superiority of one NOAC over another for our prespecified primary outcomes. Although the evidence suggests that NOACs reduce mortality, the effect size or impact is small; moreover, NOACs may increase major bleeding. Head-to-head trials, comparing NOACs against each other, are required to provide more solid evidence.

The use of andexanet alpha in the Polish setting: An interdisciplinary protocol. Expert consensus statement of the Polish Cardiac Society

Andexanet alfa (AA) is a recombinant inactive analog of human activated factor X (FXa), effectively reversing the effects of its inhibitors - rivaroxaban and apixaban, which are available in Poland. The drug was approved for clinical use registration after the publication of the results of the ANNEXA-4 trial (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of FXa Inhibitors 4), in which its efficacy in restoring hemostasis in life-threatening hemorrhages in patients receiving using the aforementioned anticoagulants was demonstrated. Hence, AA is now recommended for patients on apixaban or rivaroxaban therapy with massive and uncontrollable hemorrhages, including hemorrhagic strokes (HS) and gastrointestinal bleeding. Drug-specific chromogenic anti-Xa assays are generally best suited for estimating rivaroxaban and apixaban plasma levels, aside from direct assessment of their concentrations. The absence of anti-Xa activity, determined using these assays, allows us to rule out the presence of clinically relevant plasma concentrations of any FXa inhibitor. On the other hand, the dose of AA should not be modified based on the results of coagulation tests, as it depends solely on the time that elapsed since the last dose of FXa inhibitor and oon the dose and type of FXa inhibitor. AA is administered as an intravenous (i.v.) bolus, followed by an i.v. infusion of the drug. The maximum reversal of anti-Xa activity occurs within two minutes of the end of the bolus treatment, with the continuation of the continuous i.v. infusion allowing the effect to be maintained for up to two hours afterwards. Because anticoagulant activity can reappear after the infusion is completed, it is currently unclear at what point after AA administration FXa inhibitors or heparin should be re-administered. In Poland AA is starting to become available and its urgent need to administer it to patients with severe bleeding on apixaban or rivaroxaban.

Proteomic analysis of extracellular vesicle cargoes mirror the cardioprotective effects of rivaroxaban in patients with venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) remains a significant cause of morbidity and mortality worldwide. Rivaroxaban, a direct oral factor Xa inhibitor, mediates anti-inflammatory and cardiovascular-protective effects besides its well-established anticoagulant properties; yet, these remain poorly characterized. Extracellular vesicles (EVs) are considered proinflammatory messengers regulating a myriad of (patho)physiological processes and may be highly relevant to the pathophysiology of VTE. The effects of Rivaroxaban on circulating EVs in VTE patients remain unknown. We have established that differential EV biosignatures are found in patients with non-valvular atrial fibrillation anticoagulated with Rivaroxaban versus warfarin. Here, we investigated whether differential proteomic profiles of circulating EVs could also be found in patients with VTE.

METHODS AND RESULTS

We performed comparative label-free quantitative proteomic profiling of enriched plasma EVs from VTE patients anticoagulated with either Rivaroxaban or warfarin using a tandem mass spectrometry approach. Of the 182 quantified proteins, six were found to be either exclusive to, or enriched in, Rivaroxaban-treated patients. Intriguingly, these proteins are involved in negative feedback regulation of inflammatory and coagulation pathways, suggesting that EV proteomic signatures may reflect both Rivaroxaban's anti-coagulatory and anti-inflammatory potential.

CONCLUSIONS

These differences suggest Rivaroxaban may have pleiotropic effects, supporting the reports of its emerging anti-inflammatory and cardiovascular-protective characteristics relative to warfarin.

Factors associated with early, late, and very late stent thrombosis among patients with acute coronary syndrome undergoing coronary stent placement: analysis from the ATLAS ACS 2-TIMI 51 trial

Background

Stent thrombosis (ST) is an uncommon but serious complication of stent implantation. This study aimed to explore factors associated with early, late, and very late ST to help guide risk assessment and clinical decision-making on ST.

Methods

The analysis included patients who received stent placement for the index acute coronary syndrome (ACS). Cumulative incidence of ST was assessed at 30 days (early ST), 31-360 days (late ST), 361-720 days (very late ST), and up to 720 days. Cox proportional hazards models were used to assess associations between ST and various factors, including patient characteristics [i.e., age, sex, ACS presentation, history of hypertension, smoking, diabetes, prior myocardial infarction (MI), heart failure, prior ischemic stroke, and cancer], laboratory tests [i.e., positive cardiac biomarker, hemoglobin, platelet count, white blood cell (WBC) count], and treatment [i.e., drug-eluting stent (DES) vs. bare-metal stent (BMS) and anticoagulant with rivaroxaban vs. placebo].

Results

Among the 8,741 stented patients, 155 ST events (2.25%) occurred by Day 720. The cumulative incidences of early, late, and very late ST were 0.80%, 0.81%, and 0.77%, respectively. After multivariable adjustment, age ≥ 75 [hazard ratio (HR) = 2.13 (95% confidence interval, CI: 1.26-3.60)], a history of prior MI [HR = 1.81 (95% CI: 1.22-2.68)], low hemoglobin level [HR = 2.34 (95% CI: 1.59-3.44)], and high WBC count [HR = 1.58 (95% CI: 1.02-2.46)] were associated with a greater risk of overall ST, whereas DES [HR = 0.56 (95% CI: 0.38-0.83)] and rivaroxaban therapy [HR = 0.63 (95% CI: 0.44-0.88)] were associated with a lower risk of overall ST up to 720 days. Low hemoglobin level and high WBC count were associated with early ST (low hemoglobin: HR = 2.35 [95% CI: 1.34-4.12]; high WBC count: HR = 2.11 [95% CI: 1.17-3.81]). Low hemoglobin level and prior MI were associated with a greater risk of late ST (low hemoglobin: HR = 2.32 [95% CI: 1.26-4.27]; prior MI: HR = 2.98 [95% CI: 1.67-5.31]), whereas DES was associated with a lower risk of late ST [HR = 0.33 (95% CI: 0.16-0.67)]. Age ≥75 years was associated with very late ST.

Conclusion

The study identified positive and negative associations with early, late, and very late ST. These variables may be useful in constructing risk assessment models for ST.

Clinical Trial Registration

http://www.clinicaltrials.gov, identifier NCT00809965.

Treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia in the world. Risk factor modification, anticoagulation, rhythm control, and rate control are the four pillars of its management. American College of Cardiology/American Heart Association (ACC/AHA) guidelines on management of AF were updated recently.

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

AIM

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

METHODS

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

STRUCTURE

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

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

AIM

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

METHODS

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

STRUCTURE

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

Nomogram for predicting bleeding events in nonvalvular atrial fibrillation patients receiving rivaroxaban: A retrospective study

Background and Aims

To construct a bleeding events prediction model of nonvalvular atrial fibrillation (NVAF) patients receiving rivaroxaban.

Methods

We conducted a retrospective cohort study in patients with NVAF who received rivaroxaban from June 2017 to March 2019. Demographic information and clinical characteristics were obtained from the electronic medical system. Univariate analysis was used to find the primary predictive factors of bleeding events in patients receiving rivaroxaban. Multiple analysis was conducted to screen the primary independent predictive factors selected from the univariate analysis. Finally, the independent influencing factors were applied to build a prediction model by using R software; then, a nomogram was established according to the selected variables visually, and the sensitivity and specificity of the model was evaluated.

Results

Twelve primary predictive factors were selected by univariate analysis from 46 variables, and multivariate analysis showed that older age, higher prothrombin time (PT) values, history of heart failure and stroke were independent risk factors of bleeding events. The area under curve (AUC) for this novel nomogram model was 0.828 (95% CI: 0.763-0.894). The mean AUC over 10-fold stratified cross-validation was 0.787, and subgroup analysis validation also showed a satisfied AUC. In addition, the decision curve analysis showed that the PT in combination with CHA2DS2-VASc and HASBLED was more practical and accurate for predicting bleeding events than using CHA2DS2-VASc and HASBLED alone.

Conclusions

PT in combination with CHA2DS2-VASc and HASBLED could be considered as a more practical and accurate method for predicting bleeding events in patients taking rivaroxaban.

Acute ischemic stroke and measurement of apixaban and rivaroxaban: an observational cohort implementation study

Background

Treatment with intravenous thrombolysis for acute ischemic stroke is contraindicated with intake of apixaban/rivaroxaban in the last 48 hours. Recent European Stroke Organization guidelines suggest that thrombolysis can be considered if anti-factor Xa activity (AFXa) is <0.5 × 103 IU/L with low-molecular-weight (LMWH) or unfractionated heparin (UFH) calibrated assays. Some centers also use apixaban/rivaroxaban-calibrated AFXa assays to identify patients with low drug concentrations.

Objectives

To prospectively evaluate the first year of implementation of drug-calibrated AFXa assays at our center with 2500 yearly admittances with suspected stroke.

Methods

Samples were analyzed on Sysmex CS-5100 instruments with Innovance anti-Xa reagents. Thrombolysis could be considered with drug concentrations <25 μg/L. Patients were registered in an institutionally approved quality register. Outcomes included (1) the number of patients receiving thrombolysis after drug measurement, (2) turn-around time for drug concentration measurements, and (3) sensitivity of LMWH/UFH AFXa to apixaban and rivaroxaban.

Results

Apixaban or rivaroxaban was measured in 148 samples, and 4 patients who previously would have been ineligible for thrombolysis were treated with thrombolysis. In total, thrombolysis was administered in 123 patient episodes in the study period. The median turn-around time for the drug measurements was 38 minutes. Apixaban concentrations of 25 μg/L and 50 μg/L corresponded to LMWH/UFH AFXa of 0.13 and 0.27 × 103 IU/L, respectively. There were too few rivaroxaban results for regression analysis.

Conclusion

Implementation of apixaban and rivaroxaban measurements led to a small increase in the number of patients receiving thrombolysis. Excluding significant concentrations of apixaban or rivaroxaban using LMWH/UFH AFXa may be feasible.

Portal Vein Thrombosis With Hypoplasia in the Left Lobe of the Liver: A Case Report

Portal vein thrombosis (PVT) is an acute-onset, emergent thrombotic disease that is difficult to diagnose without an apparent underlying disease unless the clinician actively suspects its presence. We present a case of acute PVT with underlying left lobe hypoplasia of the liver, a previously undescribed condition. A 79-year-old male patient presented to the emergency department with the chief complaint of anorexia. His medical history included hypertension and an old brain infarction. The patient had no history of surgery. Contrast-enhanced CT revealed the disappearance of the left lobe of the liver and defects in the contrast effect in the left portal vein. The diagnosis reached was PVT with left lobe hypoplasia of the liver. Hypoplasia of the liver manifests few symptoms and may be identified incidentally. Clinicians need to be aware that PVT can develop from various underlying conditions, including hypoplasia of the liver, and we recommend aggressive imaging studies to help detect the presence of PVT when encountering similar cases.

Comparison of the Correlation Between Coagulation Indices and Rivaroxaban Concentrations

BACKGROUND

Rivaroxaban has predictable pharmacokinetics and pharmacodynamics. However, monitoring rivaroxaban concentrations should be provided for special patients with hepatic insufficiency, high bleeding risk, and high thrombotic risk.

OBJECTIVE

This study aimed to correlate chromogenic anti-Xa assay, prothrombin time (PT), activated partial thromboplastin time (APTT), thromboelastogram reaction time (TEG R-time), and rivaroxaban concentration measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) (MS-Riva).

METHODS

Peripheral venous blood was collected from recruited patients 30 minutes before and 2 to 4 hours after drug administration. High-performance liquid chromatography-tandem mass spectrometry and chromogenic anti-Xa assay measured rivaroxaban concentration. Different assays were compared by Pearson correlation coefficient and Bland-Altman analysis.

RESULTS

A total of 104 patients with 191 plasma were included in the study. Overall analysis shows that chromogenic anti-Xa assay, PT, APTT, and TEG R-time strongly correlated with MS-Riva (r = 0.986; r = 0.884; r = 0.741; r = 0.739; P < 0.001). Rivaroxaban peak concentration detected by HPLC-MS/MS (MS-peak) showed a very strong correlation with the chromogenic anti-Xa assay (r = 0.977, P < 0.001) and moderate correlation with PT, APTT, and TEG R-time (r = 0.670; r = 0.571; r = 0.481, P < 0.001). Rivaroxaban trough concentration detected by HPLC-MS/MS (MS-trough) correlated strongly with the chromogenic anti-Xa assay (r = 0.884, P < 0.001), weakly with APTT (r = 0.313; P = 0.043), and not significantly with PT and TEG R-time (P = 0.140; P = 0.341).

CONCLUSION AND RELEVANCE

High-performance liquid chromatography-tandem mass spectrometry/MS is the preferred choice for monitoring peak and tough concentrations, followed by anti-Xa, while PT is only suitable for peak concentrations. This study can help the clinicians to better adjust the medication regimen and reduce the risk of recurrence of thrombosis as well as the risk of bleeding.

aspirin alone as a secondary prophylaxis in patients with chronic and symptomatic peripheral arterial disease in the United States

AIM

The objective in this study was to assess the clinical and economic implications of the inclusion of rivaroxaban as a secondary prophylaxis in patients with chronic or symptomatic peripheral artery disease (PAD) in the United States (US).

METHODS

A cost-consequence model was adapted to evaluate the economic impact of rivaroxaban plus aspirin in a hypothetical 1-million-member health plan. The model inputs were taken from multiple sources: efficacy and safety of rivaroxaban + aspirin vs. aspirin alone were abstracted from COMPASS and VOYAGER randomized clinical trials; the prevalence of chronic and symptomatic PAD and incidence rates of clinical events (major adverse cardiac events [MACE], major adverse limb events [MALE], and major bleeding), were abstracted from the analysis of claims data; healthcare costs of clinical events and wholesale acquisition costs for rivaroxaban were abstracted from the literature and Red Book, respectively (2022 USD). One-way sensitivity analyses and subgroup analyses were also conducted.

RESULTS

Over one year, with a 5% uptake of rivaroxaban, the model estimated rivaroxaban + aspirin to reduce 21 MACE/MALE events in the PAD patient population. The reduction in these clinical events offsets the increased risk of major bleeding (16 additional events), demonstrating a positive health benefit of the rivaroxaban addition. These benefits led to a $0.27 incremental cost per member per month (PMPM) to a US plan. The major driver of the incremental cost was the cost of rivaroxaban. In a subgroup of patients with the presence of any high-risk factor (heart failure, diabetes, renal insufficiency, or history of vascular disease affecting two or more vascular beds), the incremental PMPM cost was $0.13.

CONCLUSIONS

Rivaroxaban + aspirin was found to provide positive net clinical benefit on the annual number of MACE/MALE avoided, with a modest increase in the PMPM cost.

Direct oral anticoagulant concentrations and adherence in stroke patients

No therapeutic ranges linking drug concentrations of apixaban and rivaroxaban to clinical outcomes have been defined. We investigated whether direct oral anticoagulant (DOAC) concentrations among patients admitted to hospital with symptoms of stroke differed between those later verified to suffer an ischaemic cerebrovascular event (stroke or transient ischaemic attack) and those having other diagnoses (control group). Serum concentrations in 102 patients on DOAC for atrial fibrillation (84%) and thromboembolic disease (16%) were measured within 24 h of the acute event, employing ultra-high performance liquid chromatography with tandem mass spectrometry. We converted all concentrations to standardized trough levels. DOAC concentrations were lower in the 64 patients with verified ischaemic cerebrovascular event than in the 30 controls, 255 ± 155 versus 329 ± 144 nmol/L (p = 0.029), despite no statistically significant difference in self-reported adherence and daily dosages. Calculated concentrations were 5.4-596 nmol/L (median = 229 nmol/L) in the ischaemic stroke group and 41-602 nmol/L (median = 316 nmol/L) in controls. CHA2 DS2 -VASc score was significantly higher in the ischaemic stroke group than in controls (4.9 ± 1.6 versus 4.1 ± 1.7; p = 0.007). These results may suggest that patients with high cerebrovascular risk might benefit from higher DOAC levels than those with a lower risk.

Rivaroxaban Plus Aspirin Versus Aspirin Alone After Endovascular Revascularization for Symptomatic PAD: Insights From VOYAGER PAD

BACKGROUND

Rivaroxaban plus aspirin compared with aspirin alone reduced major cardiac and ischemic limb events after lower extremity revascularization (LER) in the VOYAGER PAD (Vascular Outcomes Study of ASA Along With Rivaroxaban in Endovascular or Surgical Limb Revascularization for Peripheral Artery Disease) trial. The effect has not been described in patients undergoing endovascular LER.

METHODS

The VOYAGER PAD trial randomized 6564 patients with symptomatic peripheral artery disease to a double-blinded treatment with 2.5 mg of rivaroxaban BID or matching placebo and 100 mg of aspirin daily. The primary efficacy outcome was a composite of acute limb ischemia, major amputation of a vascular pathogenesis, myocardial infarction, ischemic stroke, or cardiovascular death. The principal safety end point was Thrombolysis in Myocardial Infarction major bleeding. A prespecified subgroup of patients who underwent endovascular revascularization was included.

RESULTS

Endovascular LER occurred in 4379 (66.7%) patients and surgical LER in 2185 (33.3%). Over a 3-year follow-up, rivaroxaban reduced the risk of the primary outcome by 15% (hazard ratio [HR], 0.85 [95% CI, 0.76-0.96]) with an absolute risk reduction of 0.92% at 6 months and 1.04% at 3 years and a consistent benefit in those receiving endovascular (HR, 0.89 [95% CI, 0.76-1.03]) or surgical LER (HR, 0.81 [95% CI, 0.67-0.98]; P interaction=0.43). For endovascular-treated patients, rivaroxaban reduced the risk of acute limb ischemia or major amputation of a vascular pathogenesis by 30% (HR, 0.70 [95% CI, 0.54-0.90]; P=0.005) with an absolute risk reduction of 1.0% at 6 months and 2.0% at 3 years compared with aspirin alone. Among endovascular-treated patients, the median duration of concomitant dual antiplatelet therapy with clopidogrel treatment was 31 days (interquartile range, 30-58). There was a consistent benefit for rivaroxaban regardless of background clopidogrel. Thrombolysis in Myocardial Infarction major bleeding was significantly higher for the rivaroxaban and aspirin group for the endovascular cohort (HR, 1.66 [95% CI, 1.06-2.59]) with an absolute risk increase of 0.9% at 3 years with no increase in intracranial or fatal bleeding observed (HR, 0.86 [95% CI, 0.40-1.87]; P=0.71). Mortality with rivaroxaban was higher in the endovascular-treated patients (HR, 1.24 [95% CI, 1.02-1.52]), although this finding was isolated to specific regions.

CONCLUSIONS

Rivaroxaban added to aspirin or dual antiplatelet therapy after LER for peripheral artery disease reduces ischemic risk and increases major bleeding without an increased risk of intracranial or fatal bleeding. These benefits are consistent in those treated with endovascular and surgical approaches with significant benefits for major adverse limb events. These data support the use of rivaroxaban in addition to aspirin or dual antiplatelet therapy after endovascular intervention for symptomatic peripheral artery disease.

Comparison of rivaroxaban-based dual antithrombotic and antiplatelet therapies for symptomatic patients with lower-extremity peripheral artery disease post-revascularization: a retrospective cohort study

Background

Patients with symptomatic lower-extremity peripheral artery disease (LE-PAD) are prone to serious cardiovascular and limb events. Few studies have evaluated the effect of rivaroxaban-based dual antithrombotic therapy in high-risk patients with LE-PAD in Asian populations.

Objectives

To investigate the efficacy and safety of rivaroxaban-based dual antithrombotic therapy in symptomatic patients with LE-PAD.

Design

Retrospective cohort study.

Methods

This study included patients with LE-PAD treated at the Nanjing Drum Tower Hospital from 1 January 2018 to 31 December 2021. These participants were divided into antiplatelet (APT) or antiplatelet therapy combined with rivaroxaban (RAPT) groups. The efficacy outcomes in this study were the occurrence of major adverse cardiovascular events (MACE), including myocardial infarction, ischemic stroke, or death from cardiovascular causes, and major adverse limb events (MALE), including urgent revascularization, acute limb ischemia, and major amputation. The safety outcomes included major and clinically relevant non-major (CRNM) bleeding. Patients were followed up until the time of death or the end of the study (31 March 2023).

Results

We included 1144 patients with LE-PAD (APT: 502 patients; RAPT: 642 patients). The RAPT group had a lower risk of primary composite efficacy outcomes [hazard ratio (HR): 0.40] and a nonsignificant increase in major bleeding risk (HR: 2.33) than the APT group. The RATP group also had a significantly lower risk of secondary efficacy outcomes, including ischemic stroke (HR: 0.41), myocardial infarction (HR: 0.31), cardiovascular death (HR: 0.40), and MALE (HR: 0.65), than the APT group. The CRNM bleeding incidence varied between the two groups (HR: 3.96). Moreover, no significant interactions were observed between the subgroups and treatment groups in the composite efficacy analysis.

Conclusion

Rivaroxaban-based dual antithrombotic therapy significantly reduced the occurrence of MACE in patients with LE-PAD without increasing major bleeding events. High-risk patients benefited from the dual antithrombotic therapy.

One-year retrospective analysis of anti-FXa apixaban and rivaroxaban levels demonstrates utility for management decisions in various urgent and nonurgent clinical situations

OBJECTIVES

Quantification of direct oral anticoagulant (DOAC) plasma levels can guide clinical management, but insight into clinical scenarios surrounding DOAC-calibrated anti-FXa assays is limited.

METHODS

Apixaban- and rivaroxaban-calibrated chromogenic anti-Xa assays performed over a 1-year period were retrospectively analyzed. Patient demographics, DOAC history, concomitant medications, and renal/liver comorbidities were obtained. Indications for testing and associated clinical actions were reviewed. Machine learning (ML) models predicting clinical actions were evaluated.

RESULTS

In total, 371 anti-FXa apixaban and 89 anti-FXa rivaroxaban tests were performed for 259 and 67 patients in recurring urgent (acute bleeding, unplanned procedures) and nonurgent situations, including several scenarios not captured by existing testing recommendations (eg, drug monitoring, recurrent thromboembolic events, bleeding tendency). In urgent settings, andexanet reversal was guided by radiologic and clinical findings over DOAC levels in 14 of 32 instances, while 51% of apixaban patients qualified for nonreversal strategies through the availability of levels. Levels also informed procedure/intervention timing and supported management decisions when DOAC clearance or DOAC target levels were in question. The importance of clinical context was emphasized by exploratory ML models predicting particular clinical actions.

CONCLUSIONS

Although clinical situations are complex, DOAC testing facilitates clinical decision-making, including reversal, justifying more widespread implementation of these assays.

Sucrose acetate isobutyrate (SAIB) and glyceryl monooleate (GMO) hybrid nanoparticles for bioavailability enhancement of rivaroxaban: an optimization study

This study aims to improve the RXB bioavailability using hybrid nanoparticles. A modified melt dispersion technique created different formulas with varying GMO-SAIB: RXB and GMO: SAIB ratios, with fixed GMO-SAIB: poloxamer 407 ratios. The PS, PDI, ZP, and EE were measured to determine the optimal formula, which was selected using Design-Expert™ software. The optimized formula was lyophilized and tested for PS, PDI, ZP, and EE. The chosen lyophilized formula (L4) was characterized using FTIR, DSC, PXRD, dissolution studies, and pharmacokinetics studies. The study found correlations between variables and identified how GMO-SAIB concentration affects drug encapsulation. The dissolution parameters were calculated, including % Q5 and % DE). The % Q5 values were 68.4 ± 1.7% and 89.7 ± 3.6% for Xarelto and L4 tablets, respectively. The % DE values were 89.7 ± 0.4% and 97.5 ± 2.1% for Xarelto and L4 tablets, respectively. The AUC values were 2117.0 ng.h/mL (±77.3) and 3919.4 ng.h/mL (±134.8) for Xarelto and L4 tablets, respectively. The Cmax values were 241.3 ng/mL (±21.0) and 521.5 ng/mL (±91.5) for Xarelto and L4 tablets, respectively. In conclusion, the study found that using GMO-SAIB as co-formers effectively enhanced the bioavailability of RXB. The authors recommend using the hybrid nanoparticles technique and suggest further research to enhance its effectiveness for drug delivery.

Direct Oral Anticoagulants for the Treatment of Venous Thromboembolism in Obesity

Background: Direct oral anticoagulants (DOACs) are known to have similar efficacy with a decreased risk of bleeding when compared to warfarin for the treatment of venous thromboembolism (VTE). In patients with obesity, there are limited data regarding the safety and efficacy of DOACs. Despite concerns for both under- and over-dosing patients with extremes of body weight, there are no dose adjustment recommendations in the package inserts for any of the DOACs. Objective: To evaluate the safety and efficacy of DOACs versus warfarin for the treatment of VTE in patients with obesity. Methods: This single-center, retrospective cohort study included obese patients initiated on DOAC or warfarin therapy for VTE from January 2015 to January 2022. Patients with cancer, hypercoagulable disorders, end-stage kidney disease, or pregnancy were excluded. The primary endpoint was VTE recurrence. Secondary endpoints included major and minor bleeding. Results: A total of 120 patients met criteria for inclusion. Ninety-two received DOAC therapy and 28 received warfarin. The primary endpoint occurred in 4 patients in the DOAC group and 3 patients in the warfarin group (P = 0.35). Major bleeding occurred in 2 patients. Minor bleeding events occurred in 10 (8.33%) patients. Of those, 6 (6.5%) events occurred in patients receiving a DOAC and 4 (14.3%) events occurred in patients receiving warfarin (P = 0.28). Limitations of this study include the retrospective single-center study design. Conclusions: There was a comparable risk of bleeding and recurrent VTE between DOACs and warfarin in patients initiated on therapy for VTE.

Expedited surgery does not increase transfusion rates for patients with geriatric hip fracture taking factor Xa inhibitors

Objectives

Geriatric patients who sustain hip fractures and are taking factor Xa inhibitors (Xa-I) experience surgical delay. Our institution developed a pharmacokinetic protocol to formally guide and expedite surgical timing for these patients. The protocol is based on the patient's renal function and timing of last Xa-I dose. For patients with impaired renal function, longer wait times are recommended. The purpose of this study was to determine the effects of this protocol for patients with geriatric hip fracture taking Xa-I.

Design

Retrospective cohort study.

Setting

Level 1 trauma center.

Patients/Participants

A total of 164 patients aged 65 and older who were taking Xa-I before admission and underwent hip fracture surgery; 68 patients in the Standard group (2014-2018) and 96 patients in the Expedited group (2020-2022, after protocol implementation).

Intervention

Hip fracture surgery.

Main Outcome Measurements

Time to surgery (TTS), transfusion rate, blood loss, 90-day complication rates.

Results

The median TTS was significantly shorter in the Expedited group (28.6 hours, interquartile range 21.3 hours) than in the Standard group (44.8 hours, interquartile range 21.1 hours) (P < .001). There were no differences in overall transfusion rates. Multivariable regression analysis demonstrated that time to surgery was not predictive of transfusion rate in all patients (OR 1.00, 95% CI 0.99-1.02, P = .652). There were no differences in blood loss or rates of 90-day complications.

Conclusion

Geriatric patients with hip fractures and taking factor Xa inhibitors may warrant earlier surgery without an increased risk of transfusion or bleeding.

Level of Evidence

Therapeutic Level III.

Association of type of oral anticoagulation with risk of bleeding in 45,114 patients with venous thromboembolism during initial and extended treatment-A nationwide register-based study

BACKGROUND

Safety data for different anticoagulant medications in venous thromboembolism (VTE) are scarce, in particular for extended treatment.

OBJECTIVES

To compare major bleeding rates depending on the choice of anticoagulation during initial (first 6 months) and extended treatment (6 months up to 5 years).

METHODS

A nationwide register-based study including cancer-free patients with a first-time VTE between 2014 and 2020. Cox proportional hazards models were used to compare bleeding rates.

RESULTS

We included 6558 patients on warfarin, 18,196 on rivaroxaban, and 19,498 on apixaban. At 6 months, 4750 (72.4%) remained on warfarin, 11,366 (62.5%) on rivaroxaban, and 11,940 (61.2%) on apixaban. During initial treatment, major bleeding rates were 3.86 (95% CI 3.14-4.58), 2.93 (2.55-3.31), and 1.95 (1.65-2.25) per 100 patient-years for warfarin, rivaroxaban, and apixaban, respectively, yielding adjusted hazard ratios (aHRs) of 0.89 (95% CI 0.71-1.12) for rivaroxaban versus warfarin, 0.55 (0.43-0.71) for apixaban versus warfarin, and 0.62 (0.50-0.76) for apixaban versus rivaroxaban. During extended treatment, major bleeding rates were 1.55 (1.19-1.91), 1.05 (0.85-1.26), and 0.96 (0.78-1.15) per 100 patient-years for warfarin, rivaroxaban, and apixaban, respectively, with aHRs of 0.72 (0.53-0.99) for rivaroxaban versus warfarin, 0.60 (0.44-0.82) for apixaban versus warfarin, and 0.85 (0.64-1.12) for apixaban versus rivaroxaban. Previous bleeding and increasing age were risk factors for bleeding both during initial and extended treatment.

CONCLUSION

Apixaban had a lower bleeding risk than warfarin or rivaroxaban during initial treatment. During extended treatment, bleeding risk was similar for apixaban and rivaroxaban, and higher with warfarin.

Preventive Therapies in Peripheral Arterial Disease

Atherosclerosis, while initially deemed a bland proliferative process, is now recognized as a multifactorial-lipoprotein-mediated inflammation-driven pathway. With the rising incidence of atherosclerotic disease of the lower extremity arteries, the healthcare burden and clinical morbidity and mortality due to peripheral artery disease (PAD) are currently escalating. With a healthcare cost burden of over 21 billion USD and 200 million patients afflicted worldwide, accurate knowledge regarding the pathophysiology, presentation, and diagnosis of the disease is crucial. The role of lipoproteins and their remnants in atherosclerotic vessel occlusion and plaque formation and progression has been long established. This review paper discusses the epidemiology, pathophysiology, and presentation of PAD. PAD has been repeatedly noted to portend to poor cardiovascular and limb outcomes. We discuss major therapeutic avenues for the prevention of major cardiovascular adverse events and major limb adverse events in patients with PAD.

The Association between Direct Oral Anticoagulants Prescribing Behavior and Non-Valvular Atrial Fibrillation Outcomes: An Instrumental Variable Analysis of Real-World Data

Several observational studies have compared apixaban with rivaroxaban in patients with non-valvular atrial fibrillation (NVAF), but these analyses may be confounded by unmeasured characteristics. This study used provider prescribing preference (PPP) as an instrumental variable (IV) to assess the association between prescriber choice of rivaroxaban vs. apixaban and the study outcomes of stroke/systemic embolism (SE), major bleeding, and death in a retrospective cohort of NVAF patients in the US. Initiators of either medication were linked to their prescribers and followed until the first of the study outcome, the end of rivaroxaban/apixaban use, or 365 days after initiation. PPP for each patient was the percent of rivaroxaban initiations issued by the provider for the prior 10 NVAF patients. Cox regression models tested associations between quintiles of PPP and each outcome. A total of 61,155 patients and 1726 providers were included. The IV was a strong predictor of rivaroxaban prescription (OR = 17.9; 95% CI: 16.6, 19.3). There were statistically significant associations between increasing preference for rivaroxaban and rates of major bleeding (ptrend = 0.041) and death (ptrend = 0.031), but not stroke/SE (ptrend = 0.398). This analysis provides evidence of the relative safety of apixaban over rivaroxaban for the risk of major bleeding and death.

Combination of Rivaroxaban and Amiodarone Increases Bleeding in Patients With Atrial Fibrillation

BACKGROUND

Rivaroxaban and amiodarone are commonly used for treating patients with atrial fibrillation. Drug-drug interactions between rivaroxaban and amiodarone may increase exposure to rivaroxaban. However, the clinical relevance of this drug-drug interaction is still not clear.

OBJECTIVE

The aim was to investigate the risk of bleeding in patients receiving a combination of rivaroxaban and amiodarone.

METHODS

This was a prospective observational study in which we included atrial fibrillation patients treated with rivaroxaban. The patients were divided into the rivaroxaban group and the combination of rivaroxaban and amiodarone group (the combination group). Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were performed to adjust between-group differences. The primary endpoint was defined as the time to the first occurrence of a composite of major, clinically relevant nonmajor, and minor bleeding.

RESULTS

In total, 481 atrial fibrillation patients were included in the analysis. After PSM, 154 patients in the rivaroxaban group were matched with 154 patients in the combination group. The bleeding events mainly consisted of clinically relevant nonmajor and minor bleeding. Only one patient experienced major bleeding. The primary outcome was recorded in 26.0% of patients in the combination group and 10.4% of patients in the rivaroxaban group (hazard ratio = 2.76, 95% CI = 1.55-4.93, P < 0.001). The bleeding risk was significantly higher in the combination group compared with that in the rivaroxaban group in the IPTW and stabilized IPTW analyses (hazard ratio = 2.17, 95% CI = 1.32-3.56, P = 0.002).

CONCLUSION AND RELEVANCE

The combination of rivaroxaban and amiodarone increased the risk of bleeding in patients with atrial fibrillation, especially clinically relevant nonmajor and minor bleeding. Physicians prescribing rivaroxaban and amiodarone together should be concerned about an increase in the risk of nonmajor bleeding.

dual antiplatelet therapy in endovascular treatment in peripheral artery disease and analysis of medication utilization of different lesioned vascular regions

Background

In the management of Peripheral Arterial Disease (PAD), the administration of anticoagulant or antiplatelet agents is imperative. The use of Dual Antiplatelet Therapy (DAPT) in conjunction with rivaroxaban has shown potential in mitigating adverse outcomes. Given the heterogeneity in the pathology of lower limb arteries, there is a compelling case for individualized treatment strategies.

Methods

In a single-center retrospective study on pharmacotherapy for peripheral artery disease, patients were treated with either aspirin combined with rivaroxaban or aspirin coupled with clopidogrel. The primary efficacy outcome encompassed a composite of increases in the Rutherford classification, acute limb ischemia, amputations due to vascular causes, target lesion revascularization, myocardial infarction, ischemic stroke, and cardiovascular death. The primary safety outcome was major bleeding, as defined by the Thrombolysis in Myocardial Infarction (TIMI) criteria; meanwhile, major bleeding as categorized by the International Society on Thrombosis and Haemostasis (ISTH) served as a secondary safety outcome. The study differentiated between two subgroups: patients with only above-the-knee and below-the-knee arterial lesions.

Results

From January 2016 to December 2021, 455 patients received either clopidogrel plus aspirin or rivaroxaban plus aspirin following endovascular treatment (EVT). The rivaroxaban group (n = 220) exhibited a lower incidence of primary efficacy outcomes [49.1% vs. 60.4%, hazard ratio (HR) 0.77, P = 0.006] but had more TIMI major bleeding events (5.9% vs. 2.1%, HR 2.6, P = 0.04). ISTH major bleeding events did not show a significant difference, though a higher percentage of rivaroxaban patients discontinued medication due to bleeding (10% vs. 4.7%, HR 2.2, P = 0.03). In the above-the-knee arterial disease subgroup, the rivaroxaban group demonstrated a lower incidence of primary efficacy outcomes (28.2% vs. 45.2%, HR 0.55, P = 0.02). In the below-the-knee arterial disease subgroup, no significant difference was observed in the occurrence of primary efficacy events between the two groups (58.7% vs. 64.8%, HR 0.76, P = 0.14).

Conclusion

Rivaroxaban plus aspirin improved outcomes compared to DAPT in patients with lower extremity artery disease. Similar findings were observed in the above-the-knee artery lesion-only group. However, in the below-the-knee artery lesion-only group, rivaroxaban plus aspirin did not surpass DAPT in efficacy. Regarding safety, rivaroxaban plus aspirin exhibited higher bleeding risks and more frequent treatment discontinuation than aspirin combined with clopidogrel.

[Albuminuria as a marker of atherosclerosis burden and a possible predictor of adverse events in patients with polyvascular disease]

BACKGROUND

The role of albuminuria as a marker of the atherosclerosis burden and a predictor of prognosis in patients with polyvascular disease (PD) has been little studied.

AIM

To evaluate the prevalence, association with atherosclerosis burden, and prognostic value of albuminuria in relation to cardiovascular and bleeding complications in patients with PD.

MATERIALS AND METHODS

The data was obtained from the prospective registry REGATA-1 (NCT04347200). Seventy four patients (75.7% males, median age 67 [61-69] years) with PD (CAD and peripheral arterial disease) were enrolled. All patients received aspirin and rivaroxaban 2.5 mg. The albumin-creatinine ratio in a single morning urine sample, estimated glomerular filtration rate (eGFR), and von Willebrand factor levels were determined.

RESULTS

Mild albuminuria (10-29 mg/g) was detected in 45.9% of patients, moderate and severe (≥30 mg/g) - in 29.7%; eGFR<60 ml/min - in 21.7%, chronic kidney disease (CKD) according to the full KDIGO criteria (eGFR and/or albuminuria ≥30 mg/g) - twice as often (39.2%). The frequency of nephroprotective therapy prescription was insufficient. The level of albuminuria did not correlate with von Willebrand factor (endothelial dysfunction marker), but was associated with affecting of 4-5 vascular beds (ROC AUC 0.775; p=0.011). During the follow-up (12 [8-18] months) 3 patients developed MACE, 11 - BARC 2-3 bleedings. Neither albuminuria nor eGFR were predictors of MACE, bleeding, or net clinical benefit. CKD (KDIGO) was also not associated with bleedings. CKD (KDIGO) was independent predictor of MACE (in significant multiple regression model beta - coefficient for CKD was 0.097; p=0.042), however, the small number of end points allows us to speak only of a hypothesis-generating trend. The implementation of CKD (KDIGO) has increased the predictive value of the REACH score.

CONCLUSION

Albuminuria is highly prevalent in patients with PD. It is a marker of atherosclerosis burden. CKD, diagnosed taking into account the level of albuminuria, can be used in a comprehensive assessment of cardiovascular risk in this category of patients.

Outcomes and factors associated with mortality in patients with atrial fibrillation and heart failure: FARAONIC study

BACKGROUND

Heart failure (HF) and atrial fibrillation (AF) are common and coexistent conditions.

HYPOTHESIS

To investigate the adverse events and mortality risk factors in patients with AF and HF treated with rivaroxaban in Spain.

METHODS

Multicenter, prospective and observational study with a follow-up of 2 years, that included adults, with a diagnosis of nonvalvular AF and chronic HF, anticoagulated with rivaroxaban at least 4 months before being enrolled.

RESULTS

A total of 672 patients from 71 Spanish centers were recruited, of whom 658 (97.9%) were included in the safety analysis and 552 (82.1%) in the per protocol analysis. At baseline, the mean age was 73.7 ± 10.9 years, 65.9% were male, 51.3% had HF with preserved ejection fraction and 58.7% were on New York Heart Association functional class II. CHA2 DS2 -VASc was 4.1 ± 1.5. During the follow-up, 11.6% of patients died and around one-quarter of patients were hospitalized or visited the emergency department, being HF worsening/progression the main cause (51.1%), with a 2.9% of thromboembolic events and 2.0% of acute coronary syndromes. Major bleeding occurred in 3.1% of patients, with 0.5% experiencing intracranial bleeding but no fatalities. Compliance with HF treatment was associated with a lower risk of death (hazard ratio: 0.092; 95% confidence interval: 0.03-0.31).

CONCLUSIONS

Among patients with HF and AF anticoagulated with rivaroxaban, incidences of thromboembolic or hemorrhagic complications were low. The most important factor for improving survival was compliance with HF drugs, what strengths the need for early treatment with HF disease-modifying therapy and anticoagulation.

Study of Rivaroxaban for Cerebral Venous Thrombosis: A Randomized Controlled Feasibility Trial Comparing Anticoagulation With Rivaroxaban to Standard-of-Care in Symptomatic Cerebral Venous Thrombosis

BACKGROUND

Emerging data suggest that direct oral anticoagulants may be a suitable choice for anticoagulation for cerebral venous thrombosis (CVT). However, conducting high-quality trials in CVT is challenging as it is a rare disease with low rates of adverse outcomes such as major bleeding and functional dependence. To facilitate the design of future CVT trials, SECRET (Study of Rivaroxaban for Cerebral Venous Thrombosis) assessed (1) the feasibility of recruitment, (2) the safety of rivaroxaban compared with standard-of-care anticoagulation, and (3) patient-centered functional outcomes.

METHODS

This was a phase II, prospective, open-label blinded-end point 1:1 randomized trial conducted at 12 Canadian centers. Participants were aged ≥18 years, within 14 days of a new diagnosis of symptomatic CVT, and suitable for oral anticoagulation; they were randomized to receive rivaroxaban 20 mg daily, or standard-of-care anticoagulation (warfarin, target international normalized ratio, 2.0-3.0, or low-molecular-weight heparin) for 180 days, with optional extension up to 365 days. Primary outcomes were annual rate of recruitment (feasibility); and a composite of symptomatic intracranial hemorrhage, major extracranial hemorrhage, or mortality at 180 days (safety). Secondary outcomes included recurrent venous thromboembolism, recanalization, clinically relevant nonmajor bleeding, and functional and patient-reported outcomes (modified Rankin Scale, quality of life, headache, mood, fatigue, and cognition) at days 180 and 365.

RESULTS

Fifty-five participants were randomized. The rate of recruitment was 21.3 participants/year; 57% of eligible candidates consented. Median age was 48.0 years (interquartile range, 38.5-73.2); 66% were female. There was 1 primary event (symptomatic intracranial hemorrhage), 2 clinically relevant nonmajor bleeding events, and 1 recurrent CVT by day 180, all in the rivaroxaban group. All participants in both arms had at least partial recanalization by day 180. At enrollment, both groups on average reported reduced quality of life, low mood, fatigue, and headache with impaired cognitive performance. All metrics improved markedly by day 180.

CONCLUSIONS

Recruitment targets were reached, but many eligible participants declined randomization. There were numerically more bleeding events in patients taking rivaroxaban compared with control, but rates of bleeding and recurrent venous thromboembolism were low overall and in keeping with previous studies. Participants had symptoms affecting their well-being at enrollment but improved over time.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03178864.

Reduced-Dose Rivaroxaban Is Associated with Lower All-Cause Mortality in Older Patients with Nonvalvular Atrial Fibrillation

BACKGROUND

Reduced-dose rivaroxaban (10 mg) was used in the J-ROCKET AF trial, demonstrating safety in the Asian population. It remains unclear whether treatment with reduced-dose versus full-dose rivaroxaban (20 mg/15 mg) is associated with all-cause mortality in older patients with nonvalvular atrial fibrillation. Proposed: To evaluate the effects of reduced-dose rivaroxaban on all-cause mortality in patients over 85.

METHODS

We retrospectively enrolled medical records representing the period from October 2012 to November 2016. The 2 × 2 factorial design incorporated age (≥85 vs. <85) and rivaroxaban use (reduced vs. full dose). The primary study outcomes were all-cause and cardiac-related mortality.

RESULTS

The study enrolled 2386 patients with a mean age of 76.6 ± 10.4 years; 51.8% were male. In the ≥85 group (n = 593), the reduced-dose subgroup had lower all-cause (5.3% vs. 10.6%, p = 0.02) and cardiac-related mortality (1.9% vs. 5.1%, p = 0.04), whereas the younger patients receiving reduced-dose rivaroxaban had higher all-cause mortality (3.7% vs. 1.8%, p = 0.01) but no difference in cardiac-related mortality (1.2% vs. 0.7%, p = 0.33). The rate of hospitalization for heart failure was significantly lower in the elderly group with reduced-dose rivaroxaban (7.2% vs. 15.7%, p < 0.01) but not in the younger group. After adjusting for confounders in the older group, treatment with reduced-dose rivaroxaban was associated with lower risk of all-cause mortality (adjusted HR (aHR): 0.40, 95% CI: 0.21-0.74, p < 0.01) and hospitalization for heart failure (aHR: 0.54, 95% CI: 0.29-0.99, p = 0.05). No associations were found between rivaroxaban dose and cardiac-related mortality in either group, nor between younger age and any outcome.

CONCLUSIONS

Reduced-dose rivaroxaban was associated with lower risks of all-cause mortality and hospitalization for heart failure in older patients with nonvalvular atrial fibrillation. Future studies can investigate the effect of reduced-dose rivaroxaban on prognoses in elderly individuals ≥85 years in the west.

Low-Dose Rivaroxaban to Prevent Recurrences of Venous Thromboembolism in Cancer: A Real-Life Experience with a Focus on Female Patients

BACKGROUND

The way in which to prevent recurrent venous thromboembolism (VTE) is an unmet clinical need in cancer patients. International guidelines only provide conditional recommendations and do not specify which anticoagulant and dose should be used. In the last 2 years, we have been using low-dose rivaroxaban to prevent VTE recurrences in cancer patients. The results of this real-life experience are presented in this study.

METHODS

All patients had cancer and had previously completed a cycle of at least six months of full-dose anticoagulation for the treatment of a VTE index event, before receiving a prescription of low-dose rivaroxaban (10 mg once daily) for secondary prevention of VTE. Effectiveness and safety of this therapeutic regimen were evaluated in terms of VTE recurrences, major bleedings (MB), and clinically relevant non-major bleedings (CRNMB).

RESULTS

The analysis included 106 cancer patients. Their median age was 60 years (IQR 50-69). Metastatic cancer was present in 87 patients (82.1%). Six patients (5.7%) had brain metastases. Over a median follow-up time of 333 days (IQR 156-484), the incidence of VTE recurrences was 3.8% (95%CI 1.0-9.4), with a recurrence rate of 4.0 per 100 person-years (95%CI 1.1-10.2). We observed no MB (0.0%) and three CRNMB (2.8%) (95%CI 0.6-8.1).

CONCLUSIONS

Low-dose rivaroxaban is potentially effective and safe in cancer patients that require prevention of recurrent VTE. Large-scale studies are needed to confirm these findings.