The EXPAND study: Efficacy and safety of rivaroxaban in Japanese patients with non-valvular atrial fibrillation

Antiplatelets for Cardiovascular Disease in Non-valvular AF with Rivaroxaban: A Subanalysis of the EXPAND Study

AIM

In this subanalysis of the EXPAND study, we evaluated the risks and benefits of rivaroxaban plus antiplatelet therapy (APT) for patients with non-valvular atrial fibrillation (NVAF) complicated by stable coronary artery disease (CAD), ischemic stroke, or peripheral artery disease (PAD).

METHODS

From the EXPAND study population (n=7,141), patients with NVAF complicated by stable CAD (n=886), ischemic stroke (n=1,231), or PAD (n=160) were included. Patients complicated by any of them were set as ALL (n=2,030). Patients were all treated with rivaroxaban (10 or 15 mg/day) with (+) or without (-) APT. Efficacy outcomes were symptomatic stroke＋systemic embolism (SE), symptomatic stroke＋SE＋myocardial infarction＋cardiovascular death, and all-cause death. Safety outcomes included major and any bleeding. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for differences between the APT(+) and APT(-) groups.

RESULTS

There were no significant differences in the efficacy outcomes between the APT(+) and APT(-) groups in the ALL cohort or in the CAD and STROKE sub-cohorts. In the PAD subcohort, the HR [95% CI] for all-cause death in the APT(+) group increased (4.43 [1.05-18.71]; p=0.043). In the APT(+) group, the HR [95% CI] for any bleeding increased in the ALL cohort (1.28 [1.01-1.62]; p=0.044) and STROKE subcohort (1.42 [1.01-2.01]; p=0.047), and for major bleeding in the CAD subcohort (2.00 [1.01-3.93]; p=0.046).

CONCLUSIONS

Rivaroxaban with APT did not reduce ischemic outcomes in patients with stable CAD or ischemic stroke; however, it did increase the risk of bleeding in patients with stable CAD or ischemic stroke.

[Oral anticoagulation with Edoxaban for stroke prevention in patients with atrial fibrillation: Analysis of 1-year follow-up data of routine clinical practice in Germany, Austria and Switzerland (DACH) from the ETNA-AF registry]

Hintergrund

Orale Nicht-Vitamin-K-Antikoagulanzien (NOAKs) sind sicher und wirksam in der Schlaganfallprävention bei Patienten mit Vorhofflimmern (AF). Es gibt jedoch nur wenige Daten zur Sicherheit und Wirksamkeit der oralen Antikoagulation mit Edoxaban im deutschsprachigen Raum in der Routineversorgung. Wir berichten über die Ein-Jahres-Ergebnisse der Patienten, die in Deutschland, Österreich und der Schweiz (DACH) im Rahmen der ETNA-AF-Europa-Studie mit Edoxaban zur Schlaganfallprävention behandelt wurden.

Methoden

Die ETNA-AF-Europa-Studie (Clinicaltrials.gov:NCT02 944 019) ist eine multizentrische, prospektive Beobachtungsstudie, in die mit Edoxaban zur Schlaganfallprävention bei AF behandelte Patienten (n = 13 092) aus 852 Zentren in 10 europäischen Ländern aufgenommen wurden. Die DACH-Kohorte besteht aus 5457 (41,7 %) Patienten aus Zentren in Deutschland, Österreich und der Schweiz.

Resultate

Die Patienten (74 Jahre, 2384 [44 %] Frauen) hatten im Mittel einen CHA 2 DS 2 -VASc-Score von 3,2 ± 1,4 – und eine labelkonforme Dosierung von Edoxaban wurde von 4309 Patienten (78,9 %) eingenommen. Nach einem Beobachtungszeitraum von einem Jahr traten bei 42 Patienten (0,8 %/Jahr) ein Schlaganfall oder ein systemisch embolisches Ereignis auf, und bei 36 Patienten (0,7 %/Jahr) kam es zu einem schweren Blutungsereignis, was bei 10 Patienten (0,2 %/Jahr) auf eine intrakranielle Blutung und bei 13 Patienten (0,3 %/Jahr) auf eine schwere gastrointestinale (GI) Blutung zurückzuführen war. Schwere und klinisch relevante, nicht schwere Blutungen zusammengenommen ereigneten sich bei insgesamt 72 Patienten (1,4 %/Jahr) über den Beobachtungszeitraum. Die Gesamtmortalität lag bei 179 Patienten (3,4 %/Jahr), wobei 85 (1,6 %/Jahr) an einer kardiovaskulären Todesursache verstarben. Bei Patienten mit einem erhöhten Lebensalter, einem gebrechlichen Allgemeinzustand, einem CHA 2 DS 2 -VASc-Score ≥ 4 zeigten sich eine höhere Gesamtmortalität und eine höhere Rate von Schlaganfällen sowie schweren Blutungsereignissen.

Schlussfolgerung

In Deutschland, Österreich und der Schweiz ist die Ereignisrate der Schlaganfälle und schweren Blutungen bei Patienten, die zur Schlaganfallprävention bei AF mit Edoxaban behandelt wurden, niedrig. Eine zunehmende Morbidität geht mit einer höheren Rate der relevanten klinischen Endpunkte einher.

Understanding Antithrombotic Agents for Rehabilitation Therapy: A Comprehensive Narrative Review

In rehabilitation medicine, attention must be paid to the medication. Among them, antithrombotic drugs are used for the initial treatment and secondary prevention of stroke, so as a basic knowledge, the pharmacological actions, characteristics, indications, and precautions for the use of antithrombotic drugs should be known. Antithrombotic agents are divided into antiplatelet agents and anticoagulants, and the appropriate antithrombotic agent is selected according to the main disease or condition. Antiplatelet agents include aspirin, clopidogrel, ticlopidine, prasugrel, ticagrelor, and cilostazol. Each antiplatelet agent has a different mechanism of action, characteristics, and indications, and should be prescribed with due consideration. Anticoagulants include heparin, synthetic Xa inhibitors, direct oral anticoagulants (DOACs), synthetic antithrombin agents, and warfarin. Knowledge of the mechanism of action, characteristics, and indications of each anticoagulant is necessary, as well as monitoring and dose adjustment. With regard to ischemic cerebrovascular disease (ICD) and antithrombotic agents, the first step is to classify cerebral infarction and to determine whether antiplatelet agents or anticoagulants should be used. Bleeding and recurrence prevention are important considerations in the selection of appropriate antithrombotic agents for the pathophysiology of ICD.

Effectiveness and safety of reduced-dose rivaroxaban for elderly patients with non-valvular atrial fibrillation: A subanalysis of the EXPAND study

BACKGROUND

Establishing the appropriate rivaroxaban dose in older patients with non-valvular atrial fibrillation (NVAF) is important because of the high risk of adverse events. In this EXPAND study subanalysis, we examined the safety and efficacy of standard-dose (15 mg/day) and non-recommended reduced-dose (10 mg/day) rivaroxaban in patients aged ≥65 years with NVAF and preserved renal function.

METHODS

The entire analysis population (ALL cohort [n = 3982]; ≥65 years) was divided into early elderly (ELD) (65-74 years [n = 1444]) and late ELD (≥75 years [n = 2386]) sub-cohorts. Each sub-cohort was divided into reduced-dose and standard-dose groups. Kaplan-Meier survival curves with adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were used to assess efficacy (thromboembolic events) and safety (hemorrhagic events) outcomes.

RESULTS

The aHR for major bleeding did not differ between the dosages in any of the cohorts (aHRs: 0.86-0.93). There were no significant differences in the occurrence of stroke + systemic embolism (SE) or stroke + SE + myocardial infarction (MI) + cardiovascular (CV) death among the cohorts. The aHR for MI/unstable angina + interventional/CV surgery + CV death was higher with 10-mg/day rivaroxaban than 15-mg/day rivaroxaban in the ALL cohort (aHR: 1.56 [95% CI 1.02-2.37], p = 0.039) and the late ELD sub-cohort (aHR: 1.86 [95% CI 1.01-3.42], p = 0.045).

CONCLUSIONS

Reduced-dose rivaroxaban may increase the risk of coronary artery events. The use of rivaroxaban 15 mg/day in patients with NVAF aged ≥75 years with preserved renal function was supported.

Off-label underdosing of four individual NOACs in patients with nonvalvular atrial fibrillation: A systematic review and meta-analysis of observational studies

BACKGROUND

Although several meta-analyses have examined the effects of off-label underdosing of nonvitamin K antagonist oral anticoagulants (NOACs) compared with their recommended doses in patients with atrial fibrillation (AF), they combined different kinds of NOACs in their primary analyses. Herein, we first conducted a meta-analysis to separately assess the effects of off-label underdosing versus on-label dosing of four individual NOACs on adverse outcomes in the AF population.

METHODS

The PubMed and Embase database were systemically searched until November 2021 to identify the relevant studies. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were pooled by utilizing a random-effects model.

RESULTS

A total of nine studies with 144,797 patients taking NOACs were included in the meta-analysis. In the pooled analysis, off-label underdosing of rivaroxaban was related to an increased risk of stroke or systemic embolism (HR = 1.31, 95% CI 1.05-1.63; p = .02), whereas off-label underdosing of apixaban was associated with a higher risk of all-cause death (HR = 1.21, 95% CI 1.05-1.40; p = .01). When comparing off-label underdosing versus on-label dosing of dabigatran or edoxaban, no differences were found in the primary and secondary clinical outcomes.

CONCLUSION

Off-label underdosing of rivaroxaban may increase the risk of stroke or systematic embolism, whereas off-label underdosing of apixaban may heighten the incidence of all-cause death.

Population pharmacokinetic and pharmacodynamic analysis of rivaroxaban in Chinese patients with non-valvular atrial fibrillation

Rivaroxaban, a direct factor Xa inhibitor, is widely used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to conduct a population pharmacokinetic-pharmacodynamic (PK-PD) analysis of rivaroxaban in Chinese patients with NVAF to assess ethnic differences and provide model-based precision dosing. A total of 256 rivaroxaban plasma concentrations and 244 prothrombin time (PT) measurements were obtained from 195 Chinese NVAF patients from a prospective clinical trial. The population PK-PD model was developed using nonlinear mixed effects modeling (NONMEM) software. The PK of rivaroxaban was adequately described using a one-compartment model with first-order adsorption and elimination. Estimated glomerular filtration rate (eGFR) was identified as a major covariate for apparent clearance. No single nucleotide polymorphism was identified as a significant covariate. PT exhibited a linear relationship with rivaroxaban concentration. Total bilirubin (TBIL) and eGFR were identified as significant covariates for baseline PT. According to the Monte Carlo simulation, 15 mg for Chinese patients with eGFR ≥50 mL/min and normal liver function yielded an exposure comparable to 20 mg for Caucasian patients. Patients with moderately impaired renal function may require a lower dose of rivaroxaban to avoid overexposure. Moreover, there was an approximate 26% increase in PT levels in patients with TBIL of 34 μmol/L and eGFR of 30 mL/min, which could increase the risk of major bleeding. The established population PK-PD model could inform individualized dosing for Chinese NVAF patients who are administered rivaroxaban.

Population Pharmacokinetics and Dose Optimization Based on Renal Function of Rivaroxaban in Thai Patients with Non-Valvular Atrial Fibrillation

Low-dose rivaroxaban has been used in Asian patients with direct oral anticoagulants (DOACs) eligible for atrial fibrillation (AF). However, there are few pharmacokinetic (PK) data in Thai patients to support precise dosing. This study aimed to develop a population PK model and determine the optimal rivaroxaban doses in Thai patients. A total of 240 Anti-Xa levels of rivaroxaban from 60 Thai patients were analyzed. A population PK model was established using the nonlinear mixed-effect modeling approach. Monte Carlo simulations were used to predict drug exposures at a steady state for various dosages. Proportions of patients having rivaroxaban exposure within typical exposure ranges were determined. A one-compartment model with first-order absorption best described the data. Creatinine clearance (CrCl) and body weight significantly affected CL/F and V/F, respectively. Regardless of body weight, a higher proportion of patients with CrCl < 50 mL/min receiving the 10-mg once-daily dose had rivaroxaban exposures within the typical exposure ranges. In contrast, a higher proportion of patients with CrCl ≥ 50 mL/min receiving the 15-mg once-daily dose had rivaroxaban exposures within the typical exposure ranges. The study’s findings suggested that low-dose rivaroxaban would be better suited for Thai patients and suggested adjusting the medication’s dose in accordance with renal function.

Impact of different dose reduction criteria for anti-Xa direct oral anticoagulants on bleeding complications: A single center observational study

Background

Each direct oral anticoagulant (DOAC) has different dose reduction criteria. Here, we evaluated the differences in the doses of three anti-Xa DOACs and clinical events based on the dose reduction criteria in patients with atrial fibrillation (AF).

Methods

Consecutive AF patients prescribed with anti-Xa DOACs [rivaroxaban (Riva), apixaban (Apix), and edoxaban (Edox)] between April 2011 and May 2016 were retrospectively evaluated. The incidences of thromboembolic and bleeding events were evaluated by the end of December 2020, focusing on the dose proportion.

Results

A total of 786 patients (72 ± 10 years old, 66.9% male) were enrolled in this study [Riva (n = 337), Apix (n = 239), and Edox (n = 210)]. The proportion of reduced dose prescriptions was significantly greater for Edox (79.2%) than Riva (38.7%) or Apix (31.9%). A Kaplan-Meier analysis showed that the incidence of minor bleeding was significantly higher in the Apix than other groups (p < .001), even after propensity score matching. The standard dose of Apix had significantly higher bleeding events than the other DOACs (p < .001). Moreover, 23.2% and 51.6% of the patients with a standard dose of Apix were fulfilled with the dose reduction criteria for Riva and Edox and had more minor bleeding events than the unfulfilled ones (p = .046).

Conclusions

The patients with a standard dose of Apix had a higher incidence of minor bleeding events than the other dosages. A reduced dose of apixaban was not prone to being chosen because of the dose reduction criteria, which may have been associated with a higher minor bleeding rate in patients with Apix.

Efficacy and Safety of Non-recommended Dose of New Oral Anticoagulants in Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

Introduction: The real-world treatment of atrial fibrillation (AF) often involves the prescription of new oral anticoagulants (NOACs) using dosing both lower and higher than recommended guidelines. Our study aimed to evaluate the efficacy and safety of non-recommended dosage of NOACs in AF patients. Methods: A systematic search was performed for relevant studies across multiple electronic databases (PubMed, Embase, Cochrane Library, Clinical Trials Registry) from inception to May 1, 2021. Multicenter randomized trials and observational studies were selected with key reporting measures for inclusion involved efficacy outcomes including stroke or systemic thromboembolism along with safety endpoints assessing major or clinically relevant bleeding events. Results: A total of 11 eligible studies were included involving 48,648 patients receiving recommended dose of NOACs and 50,116 patients receiving non-recommended dosage. Compared to AF patients treated with recommended dose regimens, administration of low dose of NOACs was associated with higher risk of stroke/systemic embolism (RR = 1.24, 95% CI 1.14-1.35, P < 0.00001), but without reducing bleeding risk (RR = 1.18, 95% CI 0.91-1.53, P = 0.21) and a higher risk of all-cause mortality (RR = 1.58, 95% CI 1.25-1.99, P = 0.0001). Moreover, high dose of NOACs was associated with higher risk of stroke and systemic embolism efficacy (RR = 1.71, 95% CI 1.06-2.76, P = 0.03) and a non-significant trend to a greater risk of major or clinically relevant bleeding (RR = 1.57, 95% CI 0.96-2.58, P = 0.07). Conclusions: AF patients treated with low dose of NOACs showed equivalent safety but with worse efficacy compared with recommended dose. High dose of NOACs was not superior to recommended dose regimens in preventing stroke/systemic embolism outcomes in AF patients.

Latest outcomes of transcatheter left atrial appendage closure devices and direct oral anticoagulant therapy in patients with atrial fibrillation over the past 5 years: a systematic review and meta-analysis

Left atrial appendage closure (LAAC) are emerging treatment for patients with atrial fibrillation (AF). However, data on the safety, efficacy, and medications for LAAC devices in patients with AF are lacking. We aimed to investigate the incidence of all-cause mortality, stroke, and major bleeding in AF patients with LAAC devices and DOACs. Moreover, we aimed to investigate the incidence rate of device-related thrombus (DRT) and the medications used in the management of AF patients with LAAC devices to gain insights into achieving better outcome. Based on a literature search using PubMed, EMBASE, Cochrane Library, and Web of Science databases between January 2015 and December 2020, eight LAAC device studies that used WATCHMAN and Amulet, and three DOAC studies that used rivaroxaban, with a total of 24,055 AF patients (LAAC devices, n = 2855; DOAC, n = 21,200), were included. A random-effects model was used to incorporate heterogeneity among studies. The pooled incidence of events per person-years were as follows: all-cause mortality, 0.06 (95% confidence interval [CI] 0.02-0.10) for WATCHMAN, 0.04 (95% CI 0.00-0.14) for Amulet, and 0.03 (95% CI 0.01-0.04) for rivaroxaban; stroke; 0.02 (95% CI 0.00-0.04) for WATCHMAN, 0 for Amulet, and 0.01 (95% CI 0.01-0.02) for rivaroxaban; major bleeding, 0.04 (95% CI 0.02-0.06) for WATCHMAN, 0.02 (95% CI 0.00-0.06) for Amulet, and 0.02 (95% CI 0.01-0.03) for rivaroxaban. The incidence rate of DRT was 2.3%, and complications were reported in 9%. The incidence of all-cause mortality, stroke, and major bleeding were similar between LAAC devices and DOACs. The rate of complications was acceptable, and those of DRT were lower than the average incidence reported in previous studies. However, further follow-up is needed. Concomitant anticoagulant and antiplatelet therapies should be further evaluated to find the optimal regimen for AF patients with LAAC devices.

Off-Label Underdosing or Overdosing of Non-vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation: A Meta-Analysis

Background: Several studies have investigated the role of off-label non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation (AF). We aimed to compare the effectiveness and safety outcomes between off-label underdose or overdose vs. on-label dose of NOACs in AF patients.

Methods: The PubMed database was systematically searched until August 2021. Observational cohorts were included if they compared the outcomes of off-label underdose or overdose with on-label dose of NOACs in AF patients. The risk ratios (RRs) and 95% confidence intervals (CIs) were pooled using a fixed-effects model (I² ≤ 50%) or a random-effects model (I² > 50%).

Results: A total of 15 observational studies were included. Compared with on-label dose of NOACs, off-label underdose of NOACs was associated with increased risks of stroke or systemic embolism (RR = 1.09, 95% CI 1.02–1.16), and all-cause death (RR = 1.29, 95% CI 1.10–1.52) but not ischemic stroke (RR = 1.34, 95% CI 0.76–2.36), myocardial infarction (RR = 1.08, 95% CI 0.92–1.28), major bleeding (RR = 0.97, 95% CI 0.89–1.05), intracranial hemorrhage (RR = 1.12, 95% CI 0.90–1.40), and gastrointestinal bleeding (RR = 0.96, 95% CI 0.85–1.07), whereas off-label overdose of NOACs was associated with increased risks of SSE (RR = 1.20, 95% CI 1.05–1.36), all-cause death (RR = 1.22, 95% CI 1.06–1.39), and major bleeding (RR = 1.33, 95% CI 1.16–1.52) but not gastrointestinal bleeding (RR = 1.18, 95% CI 0.99–1.42) and myocardial infarction (RR = 0.98, 95% CI 0.75–1.30).

Conclusion: Compared with on-label dose of NOACs, off-label underdose was associated with increased risks of stroke or systemic embolism and all-cause death, whereas off-label overdose of NOACs was associated with increased risks of stroke or systemic embolism, all-cause death, and major bleeding.

Effectiveness and Safety of Rivaroxaban by General Practitioners - A Multicenter, Prospective Study in Japanese Patients With Non-Valvular Atrial Fibrillation (GENERAL)

BACKGROUND

Direct oral anticoagulants have become a standard therapy for non-valvular atrial fibrillation (NVAF). However, little is known about their effectiveness/safety when prescribed by general practitioners to treat high-risk populations such as the elderly, those who are frail or have cognitive dysfunction.

METHODS AND RESULTS

In this multicenter, prospective study, a total of 5,717 NVAF patients (mean age 73.9 years) receiving rivaroxaban were registered by general practitioners, with a maximum 3-year follow up (mean 2.0±0.5 years). The primary endpoint was a composite of stroke and systemic embolism (SE). The annual incidence (per 100 person-years) of stroke/SE was 1.23% and for major bleeding, it was 0.63%. Multivariate analyses identified age ≥75 years (hazard ratio [HR]; 2.67, P<0.001) and history of ischemic stroke (HR; 1.89, P=0.005) as significant risk factors of stroke/SE, with history of major bleeding (HR; 14.9, P<0.001) and warfarin use (HR; 2.15, P=0.002) as risk factors for major bleeding events. Neither cognitive dysfunction, defined by the receipt of anti-dementia medications, nor frailty, evaluated by the classification of the Japanese Long-term Care Insurance system, correlated with stroke/SE or major bleeding events.

CONCLUSIONS

The low incidence of adverse events, including stroke/SE and bleeding, in patients prescribed rivaroxaban by general practitioners supports its use as a safe and efficacious treatment in the standard clinical care of high-risk patient populations.

Real-world safety and effectiveness of rivaroxaban using Japan-specific dosage during long-term follow-up in patients with atrial fibrillation: XAPASS

BACKGROUND

The Xarelto Post-Authorization Safety and Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) was designed to investigate safety and effectiveness during long-term follow-up of rivaroxaban treatment, using reduced doses compared with other global regions, in Japanese patients with non-valvular atrial fibrillation in real-world clinical practice.

METHODS

In this prospective, open-label, single-arm, observational study, 11,308 patients with non-valvular atrial fibrillation newly prescribed rivaroxaban (15/10 mg once daily) at 1416 sites across Japan were enrolled and followed for a mean of 2.5 years.

RESULTS

In total, 10,664 and 10,628 patients were included in the safety and effectiveness analyses, respectively. In the safety population, mean (standard deviation) age was 73.1 (9.8) years and Congestive heart failure, Hypertension, Age ≥75 years, Diabetes mellitus, previous Stroke/TIA (2 points) (CHADS2) score was 2.2 (1.3). Incidences (95% confidence intervals) of any and major bleeding were 3.77 (3.53-4.01) and 1.16 (1.03-1.29) events per 100 patient-years, respectively. Age ≥75 years, creatinine clearance <50 mL/min, diabetes mellitus, and vascular disease were independently associated with incidence of major bleeding. The primary composite effectiveness outcome of stroke, non-central nervous system systemic embolism, and myocardial infarction occurred at an incidence (95% confidence interval) of 1.32 (1.18-1.46) events per 100 patient-years. Age ≥75 years, hypertension, prior ischemic stroke/transient ischemic attack, and concomitant use of antiplatelets were independently associated with incidence of the composite outcome of stroke, non-central nervous system systemic embolism, and myocardial infarction.

CONCLUSION

In the XAPASS, a large-scale study involving a broad range of patients with non-valvular atrial fibrillation newly prescribed rivaroxaban using Japan-specific dosage in real-world clinical practice, no unexpected safety or effectiveness concerns were detected during up to 5 years of follow-up.

Association of Low Body Weight with Clinical Outcomes in Elderly Atrial Fibrillation Patients Receiving Apixaban-J-ELD AF Registry Subanalysis

PURPOSE

Although direct oral anticoagulants are effective and safe in preventing stroke in atrial fibrillation (AF) patients with low body weight, data remain limited in AF patients with extremely low body weight (<50 kg). We aimed to investigate the association of this body weight category with clinical outcomes in elderly AF patients receiving apixaban.

METHODS

The J-ELD AF Registry is a large-scale, multicenter prospective observational study of Japanese non-valvular AF patients aged ≥ 75 years taking on-label doses of apixaban. The entire cohort (3025 patients from 110 institutions) was divided into three body weight subgroups: >60 kg (n = 1019, 33.7%), 50-60 kg (n = 1126, 37.2%), and <50 kg (n = 880, 29.1%).

RESULTS

The event incidence rates (/100 person years) were 1.69, 1.82, and 1.23 for stroke or systemic embolism (P = 0.60); 1.37, 1.73, and 2.73 for bleeding requiring hospitalization (P = 0.154); 2.02, 2.67, and 4.92 for total death (P = 0.003); and 0.73, 0.95, and 1.23 for cardiovascular death (P = 0.57), respectively. After adjusting for confounders by Cox regression analysis, body weight <50 kg was not an independent risk for stroke or systemic embolism, bleeding requiring hospitalization, total death, or cardiovascular death.

CONCLUSIONS

The incidence of events in each body weight group was comparable for stroke or systemic embolism and bleeding requiring hospitalization, and body weight <50 kg might not be an independent risk for death in Japanese non-valvular AF patients aged ≥ 75 years taking on-label doses of apixaban.

Ischemic stroke, hemorrhage, and mortality in patients with non-valvular atrial fibrillation and renal dysfunction treated with rivaroxaban: sub-analysis of the EXPAND study

The EXPAND Study demonstrated the effectiveness and safety of rivaroxaban in patients with non-valvular atrial fibrillation (NVAF) in routine clinical practice in Japan. This sub-analysis was conducted to reveal the effectiveness and safety of rivaroxaban in Japanese NVAF patients according to baseline creatinine clearance (CrCl) levels and rivaroxaban doses in the EXPAND Study. We examined 6806 patients whose baseline CrCl data were available and classified them into 2 groups: normal renal function group with CrCl ≥ 50 mL/min (n = 5326, 78%) and renal dysfunction group with CrCl < 50 mL/min (n = 1480, 22%). In the normal renal function group, 1609 (30%) received 10 mg/day (under-dose), while in the renal dysfunction group, 108 (7%) received 15 mg/day (over-dose). In the normal renal function group, under-dose of rivaroxaban was associated with higher all-cause mortality, while in the renal dysfunction group, over-dose was associated with higher incidence of major bleeding. In contrast, the incidence of stroke or systemic embolism was not different between the 2 groups regardless of the dose of rivaroxaban. In the propensity score matched analysis to adjust the difference in characteristics according to doses of rivaroxaban, the incidences of clinical outcomes were comparable between the 2 dose groups in both renal function groups. These results indicate that the dose of rivaroxaban should be reduced depending on the renal function, considering the balance between risks of bleeding and ischemia.

Effect of non-recommended doses versus recommended doses of direct oral anticoagulants in atrial fibrillation patients: A meta-analysis

Background

Several observational studies have shown that the inappropriate dosing use of direct oral anticoagulants (DOACs) in atrial fibrillation (AF) that does not conform to recommendations is becoming a widespread phenomenon. Therefore, we performed a meta‐analysis and systematic review to assess the effect of non‐recommended doses versus recommended doses of DOACs on the effectiveness and safety outcomes among AF patients.

Methods

The PubMed and Ovid databases were systematically searched to identify the relevant studies until December 2020. The effect estimates were hazard ratios (HRs) and 95% confidence intervals (CIs), which were pooled using a fixed‐effects model (I² ≤ 50%) or a random‐effects model (I² > 50%).

Results

A total of 11 studies were included in this meta‐analysis. Compared with recommended dosing of DOACs, non‐recommended low dosing of DOACs was associated with increased risks of stroke or systemic embolism (SSE, HR = 1.29, 95% CI 1.12–1.49) and all‐cause death (HR = 1.37, 95% CI 1.15–1.62), but not the ischemic stroke, myocardial infarction, gastrointestinal bleeding, intracranial bleeding, and major bleeding. Compared with recommended dosing of DOACs, non‐recommended high dosing of DOACs was associated with increased risks of SSE (HR = 1.44, 95% CI 1.01–2.04), major bleeding (HR = 1.99, 95% CI 1.48–2.68), and all‐cause death(HR = 1.38, 95% CI 1.02–1.87).

Conclusion

Compared with recommended dosing of DOACs, non‐recommended low dosing of DOACs was associated with increased risks of SSE and all‐cause death. Further study should confirm the findings of non‐recommended high dosing versus recommended dosing of DOACs.

Rivaroxaban versus low-molecular weight heparin plus warfarin prevents portal vein system thrombosis after splenectomy and pericardial devascularization: A randomized clinical trial

This study aimed to evaluate the safety and efficacy of rivaroxaban in preventing portal vein system thrombosis (PVST) in patients with liver cirrhosis after splenectomy and pericardial devascularization. 70 cirrhotic patients undergoing splenectomy and pericardial devascularization were randomly assigned to rivaroxaban treatment (n=35) or low-molecular weight heparin (LMWH) plus warfarin treatment (n=35) for 30 days in this randomized controlled trial. The primary endpoint is the PVST formation. Ultrasound doctors and radiologists were blinded to the randomization results. Both groups received routine outpatient inspection every month and were followed for one year. 17 patients (48.6 %) in rivaroxaban group developed PVST, compared with 27 patients (77.1 %) in LMWH plus warfarin group (P=0.025). The incidence of PVST during the first year postoperation was significantly lower in rivaroxaban group than in LMWH plus warfarin group (F=7.901, P=0.006). The intra-group comparisons versus baseline showed the liver function improved from POD 21 to POM 1, and coagulation function improved from POM 2, in rivaroxaban group. In contrast, the liver function improved from POM 1 to POM 2, and coagulation function improved from POM 4, in LMWH plus warfarin group. The prophylactic use of rivaroxaban significantly decreases the incidence of PVST after splenectomy and pericardial devascularization in cirrhotic patients compared to LMWH plus warfarin treatment. Besides, rivaroxaban treatment was safe and effective and associated with better liver and coagulation functions improvement than LMWH plus warfarin treatment.

Rivaroxaban-associated intracranial hemorrhage in Saudi atrial fibrillation patients

Atrial fibrillation is the most common cardiac arrhythmia. Anticoagulation therapy effectively reduces systemic embolization in patients with non-valvular atrial fibrillation, but intracranial hemorrhage (ICH) is a major possible complication. This study assessed the real-time rate of rivaroxaban-associated ICH in Saudi patients.We retrospectively reviewed patients with ICH during rivaroxaban therapy, assessing clinical features and outcomes.Four cases out of 690 patients were identified in total, indicating an incidence of ICH during rivaroxaban therapy of 0.58%. Hematoma expansion developed in 1 case. Three out of four patients were discharged after ICH, and 1 patient died.The incidence of rivaroxaban-related ICH was similar to that previously reported, and the risk of hematoma expansion was low. Further studies are required to validate our results.

Long-term efficacy and safety of anticoagulation after atrial fibrillation ablation: data from the JACRE registry

BACKGROUND

Catheter ablation (CA) is an important strategy for managing atrial fibrillation (AF). However, long-term anticoagulation strategies and clinical outcomes following CA, including thromboembolism and bleeding, have not yet been elucidated.

METHODS

We established a prospective registry, called the JACRE registry, for patients on rivaroxaban or warfarin administration who received CA for AF. The outcomes up to 30 days following the procedure were reported previously. The present study involved longer follow-up of patients enrolled in this registry to evaluate long-term anticoagulation strategies and clinical outcomes.

RESULTS

Data of 975 patients (rivaroxaban, n = 823; warfarin, n = 152) were collected from 27 institutes. Patient population had mean age 63.7 ± 10.3 years, 710 (72.8%) males, mean CHA₂DS₂-VASc score 1.9 ± 1.5, and mean follow-up period 28.7 ± 12.7 months after the index procedure. Anticoagulants were continued in 496 (50.9%) patients during the follow-up. Thromboembolism occurred in 3 patients, hemorrhagic stroke in 5, and major bleeding events in 9 (annualized event rate, 0.13%, 0.22%, and 0.40% per patient-year, respectively). There were no differences in the composite event rate of thromboembolism and International Society on Thrombosis and Haemostasis major bleeding between rivaroxaban and warfarin cohorts (0.53% and 0.55% per patient-year, respectively).

CONCLUSIONS

Long-term incidence of thromboembolism was extremely low in patients with AF treated with CA, while that of major bleeding was not especially low. Clinical Trials Registry: UMIN000032829 / UMIN000032830.

Anti-Factor Xa Activity of Standard and Japan-Specific Doses of Rivaroxaban in Thai Patients With Non-Valvular Atrial Fibrillation

BACKGROUND

Recommended rivaroxaban doses for stroke prevention in atrial fibrillation (SPAF) are 20 and 15 mg/day in patients with normal and reduced renal function, respectively, but lower doses (15 and 10 mg) have been tested and approved in Japan. It is not known whether 15 and 10 mg rivaroxaban are appropriate in other Asian populations. This study compared the anti-Factor Xa (FXa) activity of 20 and 15 mg rivaroxaban in Thai patients with normal renal function and 15 and 10 mg rivaroxaban in patients with reduced renal function.

METHODS AND RESULTS

Sixty non-valvular atrial fibrillation patients receiving rivaroxaban (mean [±SD] age 69.3±9.1 years, mean creatinine clearance 59.2±22.7 mL/min) were enrolled. The anti-FXa activity of standard rivaroxaban and Japan-specific doses was measured at peak and trough concentrations. Median anti-FXa activity at peak concentrations was significantly higher for the standard than Japan-specific dose. Median anti-FXa activity measured at the trough was significantly higher for the standard dose only in those with impaired renal function. A higher proportion of patients receiving the Japan-specific rather than standard dose had anti-FXa activity at peak concentrations within the expected range (87.7% vs. 64.4%; P=0.001). One-third of those receiving the standard dose had anti-FXa activity higher than the expected range.

CONCLUSIONS

A significantly higher proportion of Thai patients receiving the Japan-specific dose of rivaroxaban had anti-FXa activity at peak concentrations within the expected range.

Impact of creatinine clearance on clinical outcomes in elderly atrial fibrillation patients receiving apixaban: J-ELD AF Registry subanalysis

BACKGROUND

Randomized clinical trials demonstrated the efficacy and safety of apixaban in preventing stroke in patients with atrial fibrillation (AF). However, data on patients with low creatinine clearance (CCr), especially CCr 15-29 mL/min, are limited.

METHODS

The J-ELD AF Registry is a large-scale, multicenter prospective observational study of Japanese nonvalvular AF patients aged ≥75 years taking on-label dose (standard dose of 5 mg bid or reduced dose of 2.5 mg bid) of apixaban. The entire cohort (3,015 patients from 110 institutions) was divided into 3 CCr subgroups: CCr ≥50 mL/min (n = 1,165, 38.6%), CCr 30-49 mL/min (n = 1,395, 46.3%), and CCr 15-29 mL/min (n = 455, 15.1%).

RESULTS

The event incidence rates (/100 person-years) were 1.76, 1.39, and 1.67 for stroke or systemic embolism (log rank P = .762); 1.39, 1.93, and 3.13 for bleeding requiring hospitalization (log rank P = .159); 1.75, 2.76, and 7.87 for total deaths (log rank P < .001); and 0.46, 0.84, and 2.62 for cardiovascular deaths (log rank P < .001), respectively. After adjusting for confounders by Cox regression analysis, CCr 15-29 was an independent risk for total death and cardiovascular death but not for stroke or systemic embolism, or bleeding requiring hospitalization.

CONCLUSIONS

The incidence of events in each CCr value group was comparable for stroke or systemic embolism and bleeding requiring hospitalization, and significantly higher for total deaths and cardiovascular deaths only in the CCr 15- to 29-mL/min group, in Japanese nonvalvular AF patients aged ≥75 years.

The problem of underdosing with direct-acting oral anticoagulants in elderly patients with nonvalvular atrial fibrillation

Unless contraindicated, anticoagulant therapy should be prescribed to elderly patients with atrial fibrillation. Direct-acting oral anticoagulants (DOACs) are superior to vitamin K antagonists for preventing stroke. This, together with their higher net clinical benefit, makes DOACs the treatment of choice in this population. However, due to the concerns about bleeding and the need for dose adjustment based on clinical variables, underdosing of DOACs is common and the risk of stroke high. Drugs with more easily adjusted doses are likely associated with a lower risk of dosing errors and, therefore, a greater protective effect. Correct dosing can ensure a maximal net benefit of DOACs in elderly patients with atrial fibrillation.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

Outcomes associated with under-dosing of rivaroxaban for management of non-valvular atrial fibrillation in real-world Japanese clinical settings

The approved dose of oral anticoagulant rivaroxaban for patients with non-valvular atrial fibrillation (NVAF) in Japan is 15 mg once daily (od) in patients whose creatinine clearance is ≥ 50 mL/min, but recent real-world studies have demonstrated that these patients often received less than the recommended dose due to bleeding concerns. The effect of under-dosing on safety and effectiveness outcomes remains unclear. We used 1-year follow-up data from the XAPASS, a real-world Japanese prospective, single-arm, observational study. Of the 11,308 patients, 6521 patients who completed a 1-year follow-up and had a creatinine clearance ≥ 50 mL/min were included in this sub-analysis. Primary endpoints were any bleeding and a composite of stroke/non-central nervous system systemic embolism (non-CNS SE)/myocardial infarction (MI). Among the 6521 patients, 4185 (64.2%; mean CHADS₂ score: 1.8) received the 15 mg od (recommended dose), whereas 2336 (35.8%; mean CHADS₂ score: 2.3) received 10 mg od (under-dose). After adjusting for patient characteristics by propensity scoring and inverse probability of treatment weighting, incidence rates of major bleeding were comparable between under-dosed patients and patients who received the recommended dose (1.34 vs. 1.63 events/100 patient-years, p = 0.197), although the incidence rates of stroke/non-CNS SE/MI were higher in under-dosed patients than in those who received the recommended dose (2.15 vs. 1.48 events/100 patient-years, p = 0.009). In Japanese clinical practice, some NVAF patients receive rivaroxaban doses inconsistent with the recommendation. Considering the total clinical benefit, the recommended dose may be preferable in terms of balance of safety and effectiveness.Clinicaltrials.gov NCT01582737.

Real-world outcomes of rivaroxaban treatment in elderly Japanese patients with nonvalvular atrial fibrillation

Direct oral anticoagulants (DOACs), such as rivaroxaban, reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). However, it is still unclear whether the stroke reduction benefit outweighs the bleeding risk in elderly Japanese patients with NVAF. The Xarelto Post-Authorization Safety and Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) was a real-world, prospective observational, post-marketing surveillance study on the safety and effectiveness of rivaroxaban in Japanese clinical practice. This sub-analysis evaluated the clinical outcomes of elderly patients aged ≥ 75 years. At the 1-year follow-up, there were 4,685 (48.91%) and 4,893 (51.09%) patients aged ≥ 75 and < 75 years, respectively. Safety and effectiveness outcomes were compared between patients aged ≥ 75 years and those aged < 75 years, and among 3 elderly sub-populations (age ranges: 75-79, 80-84, and ≥ 85 years). Patients aged ≥ 75 years had higher rates of major bleeding [2.22 vs. 1.35 events per 100 patient-years, hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.17-2.28] and composite of stroke (ischemic or hemorrhagic)/non-central nervous system (non-CNS) systemic embolism (SE)/myocardial infarction (MI) (2.41 vs. 1.21 events per 100 patient-years, HR 1.97, 95% CI 1.40-2.77) compared to patients aged < 75 years. Intracranial hemorrhage rates were < 1 event per 100 patient-years in both groups (0.85 vs. 0.59 events per 100 patient-years, HR 1.43, 95% CI 0.85-2.40). Kaplan-Meier curves of major bleeding and stroke/non-CNS SE/MI showed that no significant differences of cumulative event rates were identified among the 3 elderly sub-populations. Stepwise Cox regression analyses revealed that creatinine clearance (CrCl) (<50 mL/min), hepatic impairment, and hypertension were specific predictors for major bleeding and no specific predictors were found for stroke/non-CNS SE/MI in patients aged ≥ 75 years. In conclusion, safety and effectiveness event rates were higher in patients aged ≥ 75 years compared with those aged < 75 years, yet, no distinct differences were observed among the 3 elderly sub-populations.

Impact of direct oral anticoagulant off-label doses on clinical outcomes of atrial fibrillation patients: A systematic review

AIMS

Worldwide observational studies are evidencing discordance between guidelines and real-world practice regarding direct oral anticoagulant drug (DOAC) doses. This systematic review summarizes and evaluate DOACs use in real-world practice.

METHODS

This review was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines searching PubMed (MEDLINE) and Medscape databases.

RESULTS

Data from 75 studies showed that most of the patients treated with DOACs for stroke prevention in atrial fibrillation received doses in accordance to the guidelines. However, a significant number of patients received off-label doses (25-50% in most of the studies evaluated). DOAC overdosing was associated with increased all-cause mortality and worse bleeding events while underdosing was associated with increased cardiovascular hospitalization and, particularly for apixaban, with a nearly 5-fold increased risk of stroke.

CONCLUSION

Patients prescribed with off-label DOAC doses did not receive the full benefit of anticoagulation and presented an increased risk of stroke, bleeding and/or adverse effects.

Clinical benefits and risks of antithrombotic therapy in patients with atrial fibrillation with comorbidities - A report from the CHART-2 Study

BACKGROUND

The benefits of antithrombotic therapy (ATT) for atrial fibrillation (AF) are occasionally offset by major bleeding complications. However, the clinical benefits and risks of ATT in AF patients, with special references to comorbidities, such as heart failure (HF), coronary artery disease (CAD), and the patterns of AF, remain to be fully elucidated.

METHODS

A total of 3221 consecutive AF patients from our Chronic Heart Failure Analysis and Registry in the Tohoku District-2 (CHART-2) Study (N = 10,219) were divided into 4 groups based on ATT at enrollment; no-ATT, anticoagulant alone, antiplatelet alone, and both of them (AC&AP). Then, efficacy and safety outcomes including thromboembolic events, major bleeding, and mortality were evaluated among the 4 groups.

RESULTS

Anticoagulant monotherapy was associated with reduced risk of ischemic stroke in patients with but not in those without HF, CAD, or non-paroxysmal AF. Although there was no significant difference in major bleeding among the 4 groups, a composite of thromboembolism and major bleeding occurred more frequently in the AC&AP group, even in combination with anticoagulants and single antiplatelet therapy, indicating that the combination therapy is more harmful than anticoagulant monotherapy for AF patients, especially for those with HF or CAD. Lastly, no-ATT group was associated with worse prognosis compared with other 3 groups.

CONCLUSIONS

These results indicate that ATT is beneficial for AF patients particularly for those with HF, CAD, or non-paroxysmal AF and that among ATT, anticoagulant monotherapy may be most profitable for both clinical benefits and risks for AF patients.

Analysis of Effectiveness, Safety, and Bleeding Related to Rivaroxaban in Elderly Patients

This study explored the efficacy and safety of rivaroxaban in elderly patients, at different doses and age of patients, and analyzed risk factors of bleeding. A retrospective analysis was conducted of 299 patients aged 60 years or older who were admitted to the First Hospital of Jilin University between January 2016 and August 2018. It was found that the rate of bleeding events (but not embolism) significantly increased as the dose of oral rivaroxaban increased (P < .001), and with age, especially in patients aged ≥80 years (P = .001, both). The multivariate logistic regression analysis indicated that age (odds ratio [OR]: 2.963, 95% CI: 1.627-5.396) and the daily dose of rivaroxaban (OR: 2.325, 95% CI: 1.483-3.645) were independent risk factors for bleeding. The study determined that rivaroxaban anticoagulant therapy is effective in the elderly patients, but the risk of bleeding increases with age, and is a concern especially in the most old patients. The recommended daily dose of rivaroxaban is effective, but a lower dose is safer for the elderly patients.

Racial and Ethnic Differences in Response to Anticoagulation: A Review of the Literature

INTRODUCTION

Anticoagulants are among the most frequently prescribed medications in the United States. Racial and ethnic disparities in incidence and outcomes of thrombotic disorders are well-documented, but differences in response to anticoagulation are incompletely understood.

OBJECTIVE

The objective of this review is to describe the impact of race and ethnicity on surrogate and clinical end points related to anticoagulation and discuss racial or ethnic considerations for prescribing anticoagulants.

METHODS

A PubMed and MEDLINE search of clinical trials published between 1950 and May 2018 was conducted using search terms related to anticoagulation, specific anticoagulant drugs, race, and ethnicity. References of identified studies were also reviewed. English-language human studies on safety or efficacy of anticoagulants reporting data for different races or ethnicities were eligible for inclusion.

RESULTS

Seventeen relevant studies were identified. The majority of major trials reviewed for inclusion either did not include representative populations or did not report on the racial breakdown of participants. Racial differences in pharmacokinetics, dosing requirements, drug response, and/or safety end points were identified for unfractionated heparin, enoxaparin, argatroban, warfarin, rivaroxaban, and edoxaban.

CONCLUSIONS

Race appears to influence drug concentrations, dosing, or safety for some but not all direct oral anticoagulants. This information should be considered when selecting anticoagulant therapy for nonwhite individuals.

Cryoballoon Ablation Induced Hyperkalemia due to Possible Cold Agglutinin Disease

Cryoballoon ablation is a well-established therapeutic tool for paroxysmal atrial fibrillation (PAF). We herein report a rare case of a 69-year-old man with PAF undergoing hemodialysis due to chronic kidney disease who developed hyperkalemia caused by possible cold agglutinin disease during cryoballoon ablation therapy. During the procedure, his electrocardiogram showed wide QRS when we finished cryoablation therapy. We detected hyperkalemia and performed urgent hemodialysis. We should bear in mind that cold agglutinin disease can occur during cryoballoon ablation.

A multicenter prospective cohort study to investigate the effectiveness and safety of apixaban in Japanese elderly atrial fibrillation patients (J-ELD AF Registry)

BACKGROUND

A global, randomized clinical trial indicated the efficacy and safety of apixaban in stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). However, data in the elderly NVAF patients ≥75 years, especially those on reduced dose, are limited.

HYPOTHESIS

To confirm the current dose reduction criteria of apixaban in elderly NVAF patients.

METHOD

With a large-scale, multicenter prospective observational study, one-year outcomes after administration of on-label doses of apixaban were analyzed in Japanese NVAF patients aged ≥75 years. Endpoints were stroke or systemic embolism, bleeding requiring hospitalization, total death, and cardiovascular death.

RESULTS

A total of 3031 patients (average age, 81.7 years; female, 48.2%) taking standard (5 mg bid) or reduced dose (2.5 mg bid) of apixaban were enrolled from 110 facilities. Standard and reduced apixaban doses were administered in 1284 (42.4%) and 1747 (57.6%) patients, respectively. Event rates (/100 person-years) in standard and reduced dose groups were 1.67 and 1.56, respectively, for stroke or systemic embolism, 1.42 and 2.25 for bleeding requiring hospitalization, 1.41 and 4.46 for total death, and 0.41 and 1.36 for cardiovascular death. Reduced apixaban dose was not significantly associated with stroke or systemic embolism and bleeding requiring hospitalization, but was independently associated with total and cardiovascular death.

CONCLUSIONS

Incidences of stroke or systemic embolism and bleeding requiring hospitalization were similar between standard and reduced apixaban doses in the elderly NVAF patients. The incidences of total and cardiovascular death were significantly higher in the reduced dose group due to the coexisting higher risks in this group.

Clinical risk factors of stroke and major bleeding in patients with non-valvular atrial fibrillation under rivaroxaban: the EXPAND Study sub-analysis

For Japanese patients with non-valvular atrial fibrillation (NVAF), the risk of stroke and major bleeding events was assessed by using the CHADS_2, CHA₂DS₂-VASc, and HAS-BLED scores. The risk factors for embolism and major bleeding under DOAC may be different from current reports. We analyzed the data set of the EXPAND Study to determine the risk factors for events among Japanese NVAF patients in the era of direct oral anticoagulant. Using the data of EXPAND Study, the validity for predictability of the CHADS₂, CHA₂DS₂-VASc, and HAS-BLED scores was identified using the receiver operating characteristic curve analysis. Multivariate analysis was performed with the Cox proportional hazard model to determine the independent risk factors for stroke/systemic embolism and major bleeding among NVAF patients receiving rivaroxaban. Explanatory variables were selected based on the univariate analysis. A total of 7141 patients (mean age 71.6 ± 9.4 years, women 32.3%, and rivaroxaban 15 mg per day 56.5%) were included. Incidence rates of stroke/systemic embolism and major bleeding were 1.0%/year and 1.2%/year, respectively. The multivariate analysis revealed that only history of stroke was associated with stroke/systemic embolism (hazard ratio 3.4, 95% confidence interval 2.5-4.7, p < 0.0001). By contrast, age (1.7, 1.1–2.6, p = 0.0263), creatinine clearance (CrCl) 30–49 mL/min (1.6, 1.2-2.2, p = 0.0011), liver dysfunction (1.7, 1.1–2.8, p = 0.0320), history/disposition of bleeding (1.8, 1.0–3.0, p = 0.0348), and concomitant use of antiplatelet agents (1.6, 1.2–2.3, p = 0.0030) were associated with major bleeding. This sub-analysis showed that some components of the HAS-BLED score were independently associated with major bleeding in Japanese NVAF patients receiving anticoagulation therapy by rivaroxaban. Additionally, CrCl value of 30–49 mL/min was an independent predictor of major bleeding in patients receiving rivaroxaban.

International longitudinal registry of patients with atrial fibrillation and treated with rivaroxaban: RIVaroxaban Evaluation in Real life setting (RIVER)

Background

Real-world data on non-vitamin K oral anticoagulants (NOACs) are essential in determining whether evidence from randomised controlled clinical trials translate into meaningful clinical benefits for patients in everyday practice. RIVER (RIVaroxaban Evaluation in Real life setting) is an ongoing international, prospective registry of patients with newly diagnosed non-valvular atrial fibrillation (NVAF) and at least one investigator-determined risk factor for stroke who received rivaroxaban as an initial treatment for the prevention of thromboembolic stroke. The aim of this paper is to describe the design of the RIVER registry and baseline characteristics of patients with newly diagnosed NVAF who received rivaroxaban as an initial treatment.

Methods and results

Between January 2014 and June 2017, RIVER investigators recruited 5072 patients at 309 centres in 17 countries. The aim was to enroll consecutive patients at sites where rivaroxaban was already routinely prescribed for stroke prevention. Each patient is being followed up prospectively for a minimum of 2-years. The registry will capture data on the rate and nature of all thromboembolic events (stroke / systemic embolism), bleeding complications, all-cause mortality and other major cardiovascular events as they occur. Data quality is assured through a combination of remote electronic monitoring and onsite monitoring (including source data verification in 10% of cases). Patients were mostly enrolled by cardiologists (n = 3776, 74.6%), by internal medicine specialists 14.2% (n = 718) and by primary care/general practice physicians 8.2% (n = 417). The mean (SD) age of the population was 69.5 (11.0) years, 44.3% were women. Mean (SD) CHADS₂ score was 1.9 (1.2) and CHA₂DS₂-VASc scores was 3.2 (1.6). Almost all patients (98.5%) were prescribed with once daily dose of rivaroxaban, most commonly 20 mg (76.5%) and 15 mg (20.0%) as their initial treatment; 17.9% of patients received concomitant antiplatelet therapy. Most patients enrolled in RIVER met the recommended threshold for AC therapy (86.6% for 2012 ESC Guidelines, and 79.8% of patients according to 2016 ESC Guidelines).

Conclusions

The RIVER prospective registry will expand our knowledge of how rivaroxaban is prescribed in everyday practice and whether evidence from clinical trials can be translated to the broader cross-section of patients in the real world.

Trial registration

Unique identifier: NCT02444221. Registerd 14 May 2015; Retrospectively Registered.

Effectiveness of Nonvitamin K Antagonist Oral Anticoagulants and Warfarin for Preventing Further Cerebral Microbleeds in Acute Ischemic Stroke Patients with Nonvalvular Atrial Fibrillation and At Least One Microbleed: CMB-NOW Multisite Pilot Trial

BACKGROUND

Nonvitamin K antagonist oral anticoagulants (NOACs) are considered superior, or at least noninferior, to warfarin in preventing stroke or systemic embolism in patients with nonvalvular atrial fibrillation. Here, we recruited acute ischemic stroke patients with nonvalvular atrial fibrillation and at least one cerebral microbleed (CMB), and evaluated the proportion of patients who had an increased number of CMBs (%) after receiving anticoagulant therapy with NOACs or with warfarin for 12 months.

METHODS

This was a multicenter, prospective, observational cohort study at 20 centers, conducted between 2015 and 2017, in which we recruited 85 patients with at least one CMB detected by 1.5T magnetic resonance imaging (T2*WI) at baseline, who received NOACs or warfarin for at least 12 months. We compared the proportions of patients with increased numbers of CMBs in the NOACs and warfarin treatment groups.

RESULTS

The proportions of patients with increased numbers of CMBs at month 12 of treatment were 28.6% and 66.7% in the NOACs and warfarin groups, respectively. The new CMBs showed no specific regional localization in either group. In the NOACs and warfarin groups, physicians prescribed lower-than-standard dosing in 13.3% and 50% of the cases, respectively. The administration of reduced doses at physicians' discretion did not appear to alter the incidence of new CMBs.

DISCUSSION

This is the first evidence to suggest efficacy of NOACs for preventing further CMBs in patients with at least one CMB, although no statistical evaluation was carried out.

Rivaroxaban or Apixaban for Non-Valvular Atrial Fibrillation - Efficacy and Safety of Off-Label Under-Dosing According to Plasma Concentration

BACKGROUND

Practice-based investigations on direct oral anticoagulant (DOAC) treatment for non-valvular atrial fibrillation (NVAF) have shown that off-label under-dosing is increasingly becoming an issue. Here, we investigate the significance of drug monitoring to prevent undesirable under-dosing with DOAC. Methods and Results: In 255 outpatients with NVAF undergoing treatment with rivaroxaban or apixaban we estimated the cut-offs for bleeding events using drug plasma concentration (PC) data 3 h after drug treatment, that is, at the peak level. Furthermore, we evaluated the appropriateness of labeled and off-label dosing implemented for 348 patients using the obtainable PC threshold. A total of 73 off-label under-dose users of rivaroxaban (37% of all users and 63% of lower dose users) had acceptable peak PC (155-400 ng/mL). Additionally, 46 off-label under-dose users of apixaban (31% of all users and 55% of lower dose users) received appropriate doses according to peak PC threshold (90-386.4 ng/mL). These off-label under-dose users reported no bleeding or thromboembolic events during follow-up.

CONCLUSIONS

Anticoagulation monitoring enables personalized and appropriate off-label under-dosing in NVAF patients on rivaroxaban or apixaban through the measurement of peak PC during DOAC use.

Comparative Effectiveness and Safety of Rivaroxaban in Adults With Nonvalvular Atrial Fibrillation

BACKGROUND

All evidence regarding benefits and harms of rivaroxaban for stroke prevention has not been appraised yet.

STUDY QUESTION

What are the comparative effectiveness and safety of rivaroxaban in adults with nonvalvular atrial fibrillation?

DATA SOURCES

Randomized controlled trials (RCTs), meta-analyses, and observational studies were identified in several databases in October 2018.

STUDY DESIGN

Rapid review with evidence appraisal using the Grading of Recommendations Assessment, Development and Evaluation working group approach.

RESULTS

Two direct RCTs (23,021 patients) suggest that rivaroxaban is noninferior to warfarin in the prevention of stroke and systemic embolism (pooled relative risk [RR] 0.73, 95% confidence interval [CI], 0.43-1.24), reduces risk of hemorrhagic stroke (RR 0.59, 95% CI, 0.38-0.92), fatal bleeding (RR 0.49, 95% CI, 0.31-0.76), and cardiac arrest (RR 0.45, 95% CI, 0.25-0.82, 2 RCTs), but increases risk of major gastrointestinal bleeding (RR 1.46, 95% CI, 1.19-1.78). In observational studies, rivaroxaban is associated with lower risk of ischemic stroke (RR 0.87, 95% CI, 0.77-0.99, 222,750 patients), acute myocardial infarction (RR 0.61, 95% CI, 0.48-0.78, 73,739 patients), and intracranial hemorrhage (RR 0.64, 95% CI, 0.45-0.92, 197,506 patients) but higher risk of gastrointestinal bleeding (RR 1.30, 95% CI, 1.19-1.42, 188,968 patients) and higher risk of mortality when compared with warfarin in European studies (RR 1.19, 103,270 patients in the UK; RR 2.02, 22,358 patients in Denmark) but lower risk of mortality in Taiwan (RR 0.58, 40,000 patients). Network meta-analyses and observational studies suggest that rivaroxaban is associated with higher risk of bleeding when compared with apixaban (RR 2.14, 72,586 patients), dabigatran (RR 1.24, 67,102 patients), and edoxaban (RR 1.32, 71,683 patients).

CONCLUSIONS

Research on the long-term comparative effectiveness, safety, and effects on quality of life between rivaroxaban and other novel oral anticoagulants is urgently needed.

Primary and secondary prevention of stroke and systemic embolism with rivaroxaban in patients with non-valvular atrial fibrillation : Sub-analysis of the EXPAND Study

The EXPAND Study examined the real-world efficacy and safety of rivaroxaban for the prevention of stroke and systemic embolism (SE) in Japanese patients with non-valvular atrial fibrillation (NVAF). In this sub-analysis, we compared the differences in efficacy and safety between patients with and those without history of stroke or transient ischemic attack (TIA). This multicenter, prospective, non-interventional, observational, cohort study was conducted at 684 medical centers in Japan. A total of 7141 NVAF patients aged ≥ 20 years [mean age 71.6 ± 9.4 (SD) years] who were being or planned to be treated with rivaroxaban (10 mg/day, 43.5%; 15 mg/day, 56.5%) were followed for a mean period of 897.1 ± 206.8 days with a high follow-up rate (99.7%). The primary prevention group comprised patients without history of ischemic stroke or TIA (n = 5546, 77.7%), and the secondary prevention group comprised those with history of ischemic stroke or TIA (n = 1595, 22.3%). In the primary and secondary prevention groups, the incidence rate of stroke or SE (primary efficacy endpoint) was 0.7 and 2.2%/year, respectively (P < 0.001), and the incidence rate of major bleeding (primary safety endpoint) was 1.2 and 1.5%/year, respectively (P = 0.132). For major bleeding events, the incidence rate of intracranial bleeding was 0.4 and 0.8%/year (P = 0.002) in the primary and secondary prevention groups, respectively. This sub-analysis of the EXPAND Study showed that the Japan-specific dosages of rivaroxaban were effective and safe in Japanese NVAF patients with and those without ischemic stroke or TIA in routine clinical practice.