Direct oral anticoagulants versus warfarin for preventing stroke and systemic embolic events among atrial fibrillation patients with chronic kidney disease

Efficacy and Safety of Direct Oral Anticoagulants Versus Warfarin in Saudi Patients With Atrial Fibrillation

INTRODUCTION

Atrial fibrillation (AF) significantly heightens stroke risk, which can be mitigated through anticoagulation therapy. Although warfarin was traditionally employed for this purpose, the use of direct-acting oral anticoagulants (DOACs) is on the rise.

METHODS

This retrospective study, which spanned from June 2016 to January 2018, focused on adult patients diagnosed with AF. Their treatments, either via warfarin or DOACs (apixaban, rivaroxaban, and dabigatran), were evaluated. Data analysis was done using Statistical Product and Service Solutions (SPSS, version 21; IBM SPSS Statistics for Windows, Armonk, NY). This study aims to evaluate the safety and effectiveness of DOACs versus warfarin in preventing thromboembolic complications among Saudi patients with AF.

RESULTS

A total of 396 patients with AF, averaging 66 ± 14 years of age, were part of the study. Among them, there were slightly more female patients (205 or 51.8%). The majority of patients (223 or 56.3%) were treated with a DOAC, while the rest (173 or 43.7%) received warfarin. Furthermore, 93 patients (23.5%) were taking anti-platelet drugs. Statistically, the rate of ischemic stroke was significantly higher among patients treated with DOACs than with warfarin (p=0.005), but bleeding rates were similar in both groups. Specifically, the DOACs apixaban and rivaroxaban showed a significant association with the occurrence of stroke when compared to warfarin (p=0.012 and p=007, respectively).

CONCLUSION

Overall, both DOACs and warfarin presented similar results regarding hemorrhagic complications when treating AF patients. However, the DOACs apixaban and rivaroxaban displayed higher risks of ischemic stroke compared to warfarin.

Direct oral anticoagulants versus vitamin K antagonists in patients with atrial fibrillation and stage 5 chronic kidney disease under dialysis: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In patients with atrial fibrillation (AF) and normal or slightly impaired renal function, the use of direct oral anticoagulants (DOACs) is preferable to vitamin K antagonists (VKAs). However, in patients undergoing hemodialysis, the efficacy, and safety of DOACs compared with VKAs are still unknown.

PURPOSE

To review current evidence about the safety and efficacy of DOACs compared to VKAs, in patients with AF and chronic kidney disease under hemodialysis.

METHODS

We systematically searched PubMed, Scopus, and Cochrane databases for RCTs comparing DOACs with VKAs for anticoagulation in patients with AF on dialysis therapy. Outcomes of interest were: (1) stroke; (2) major bleeding; (3) cardiovascular mortality; and (4) all-cause mortality. Statistical analysis was performed using RevMan 5.1.7 and heterogeneity was assessed by I2 statistics.

RESULTS

Three randomized controlled trials were included, comprising a total of 383 patients. Of these, 218 received DOACs (130 received apixaban; 88 received rivaroxaban), and 165 were treated with VKAs (116 received warfarin; 49 received phenprocoumon). The incidence of stroke was significantly lower in patients treated with DOACs (4.7%) compared with those using VKAs (9.5%) (RR 0.42; 95% CI 0.18-0.97; p = 0.04; I2 = 0%). However, the difference was not statistically significant in the case of ischemic stroke specifically (RR 0.42; 95% CI 0.17-1.04; p = 0.06; I2 = 0%). As for the major bleeding outcome, the DOAC group (11%) had fewer events than the VKA group (13.9%) but without statistical significance (RR 0.75; 95% CI 0.45-1.28; p = 0.29; I2 = 0%). There was no significant difference between groups regarding cardiovascular mortality (RR 1.23; 95% CI 0.66-2.29; p = 0.52; I2 = 13%) and all-cause mortality (RR 0.98; 95% CI 0.77-1.24; p = 0.84; I2 = 16%).

CONCLUSION

This meta-analysis suggests that in patients with AF on dialysis, the use of DOACs was associated with a significant reduction in stroke, and a numerical trend of less incidence of major bleeding compared with VKAs, but in this case with no statistical significance. Results may be limited by a small sample size or insufficient statistical power.

Direct oral anti-Xa anticoagulants versus warfarin in newly diagnosed atrial fibrillation and CKD: the Korean National Health Insurance Data

Introduction

Despite the benefits of direct oral anti-Xa anticoagulants (DOACs), the risk-benefit profile of DOAC therapy compared to warfarin therapy in patients with non-valvular atrial fibrillation (AF) and chronic kidney disease (CKD), including end-stage renal disease (ESRD), is uncertain.

Methods

We conducted a retrospective study using the Korea National Health Insurance Database from 2013 to 2018. We evaluated patients with incident non-valvular AF and CKD. The primary and secondary effectiveness outcomes were ischemic stroke and all-cause mortality. The primary safety outcomes included intracranial hemorrhage, gastrointestinal bleeding, and extracranial or unclassified major bleeding.

Results

Among the 1,885 patients evaluated, 970 (51.5%) initiated warfarin therapy, and 915 (48.5%) initiated DOAC therapy. During a mean follow-up period of 23.8 months, there were 293 and 214 cases of ischemic stroke and all-cause death, respectively. Kaplan-Meier survival analysis showed significantly lower all-cause mortality in DOAC users than in warfarin users. In multivariate Cox regression analyses, DOAC therapy had a hazard ratio for all-cause mortality of 0.41 (95% CI, 0.30-0.56; p < 0.001) compared to warfarin therapy. Additionally, DOAC therapy significantly reduced intracranial hemorrhage and gastrointestinal bleeding.

Discussion

Our study demonstrates that DOAC therapy has a better risk-benefit profile than warfarin therapy in patients with AF and CKD. Further well-designed clinical trials are needed to clarify the benefits of DOACs in this patient population.

The Safety of Direct Oral Anticoagulants Compared to Warfarin in Patients Hospitalized With Acute Kidney Injury

BACKGROUND

Direct oral anticoagulants (DOACs) are preferred over warfarin for many indications, though their safety has not been well established in patients with acute renal impairment.

OBJECTIVE

The purpose of this study was to evaluate the frequency of bleeding complications associated with DOACs compared with warfarin in patients admitted to the hospital with acute kidney injury (AKI).

METHODS

This was a retrospective cohort study evaluating patients admitted to the Penn Medicine Lancaster General Hospital with a diagnosis of AKI from October 2017 through September 2021 and receiving therapy with oral anticoagulants. Comparing DOACs with warfarin, the primary endpoint was the percent frequency of composite major and minor bleeding during the admission and within 30 days of discharge.

RESULTS

There were 112 hospitalization encounters included in the study. Of these, 42 (37.5%) patients were receiving warfarin and 70 (62.5%) patients were receiving DOAC therapy before admission. There was a higher frequency of the primary endpoint of bleeding in patients receiving DOACs as compared with warfarin, though this was not statistically significant (18.5% vs. 11.9%, respectively, P = 0.432). There were no differences between groups in the frequency of major bleeding, minor bleeding, or transfusions. Patients receiving DOAC therapy were more likely to experience anticoagulation-related readmissions or emergency department visits compared with patients on warfarin therapy (11.4% vs. 0%, P = 0.024).

CONCLUSION AND RELEVANCE

Direct oral anticoagulants and warfarin were associated with statistically similar rates of bleeding in patients presenting with AKI. Further research is necessary to elucidate if DOACs are safer than warfarin in this patient population.

Renal Function and Clinical Outcomes Among Elderly Patients With Nonvalvular Atrial Fibrillation From ANAFIE

Background

Advancing age, decreasing renal function, and atrial fibrillation are strongly associated. Real-world evidence of direct oral anticoagulant (DOAC) use among elderly patients ≥75 years of age with nonvalvular atrial fibrillation and renal dysfunction is limited.

Objectives

This study sought to assess 2-year outcomes and anticoagulant treatment, stratified by renal function.

Methods

Enrolled patients were divided into 4 subgroups by creatinine clearance (CrCl) to determine the impact of renal dysfunction on clinical outcomes.

Results

Of 32,275 patients, 26,202 with CrCl data were analyzed (median follow-up 2.00 [IQR: 1.92-2.00] years); 1.3% of patients had CrCl <15 mL/min, 10.7% had CrCl 15 to <30 mL/min, 33.4% had CrCl 30 to <50 mL/min, 35.8% had CrCl ≥50 mL/min, and 18.9% had unknown CrCl. Cumulative incidences of stroke/systemic embolic events, major bleeding, major plus clinically relevant nonmajor bleeding, cardiovascular death, all-cause death, and net clinical outcomes increased with decreasing CrCl. In multivariable Cox regression analysis, lower CrCl emerged as an independent risk factor for these clinical outcomes, except for major bleeding, compared with CrCl ≥50 mL/min. The effectiveness and safety of DOACs over warfarin were similar or better across 3 CrCl subgroups with CrCl 15 mL/min or more. DOAC use was associated with a lower risk of stroke/systemic embolic events, major bleeding, cardiovascular death, all-cause death, and net clinical outcome compared with warfarin in patients with CrCl 30 to <50 mL/min.

Conclusions

Incidences of major clinical outcomes increased with decreasing renal function in elderly nonvalvular atrial fibrillation patients. DOACs were effective and safe even in patients with renal dysfunction (CrCl 15-<50 mL/min). (Prospective Observational Study in Late-Stage Elderly Patients with Non-Valvular Atrial Fibrillation: All Nippon AF In Elderly Registry [ANAFIE Registry]; UMIN000024006).

Oral Anticoagulation in Patients with Chronic Kidney Disease and Non-Valvular Atrial Fibrillation: The FAERC Study

Atrial fibrillation (AF) is the most common arrhythmia in patients with chronic kidney disease (CKD), and its presence is associated with a higher risk of stroke and mortality.

MATERIAL AND METHODS

The FAERC study performed a retrospective multicentre analysis of historical cohorts in which data were collected from arrhythmia diagnosis onwards.

RESULTS

We analysed a Spanish cohort of 4749 patients with CKD (mean eGFR 33.9 mL/min) followed up in the nephrology clinic, observing a 12.2% prevalence of non-valvular AF. In total, 98.6% of these patients were receiving anticoagulant treatment, mainly with coumarins (79.7%). Using direct-acting oral anticoagulants (DOACs) was associated with fewer cerebrovascular events than using acenocoumarol, but in contrast with other studies, we could not corroborate the association of risk of bleeding, coronary events, or death with a type of anticoagulant prescribed.

CONCLUSIONS

Atrial fibrillation is highly prevalent in renal patients. Direct-acting anticoagulants seem to be associated with fewer ischemic-embolic complications, with no differences in bleeding, coronary events, or mortality rates.

Thrombodynamics Test in Assessing the Risk of Thrombus Formation in Patients with Atrial Fibrillation Taking Direct Oral Anticoagulants

Aim. To evaluate thrombus characteristics in patients with atrial fibrillation (AF) taking different direct oral anticoagulants (DOACs) using Thrombodynamics test.Materials and methods. Thrombodynamics test was performed in 100 patients with paroxysmal and permanent forms of AF taking different DOACs, dose choice was done in accordance with the instructions for drugs use. For analysis samples of fresh citrated platelet-free plasma were taken just before regular DOACs dose intake (trough concentration). Statistical data processing was carried out using R software packages.Results. All patients had no history of thrombosis or bleeding before inclusion in this study. All parameters of Thrombodynamics test taken at residual concentration of DOACs were in general within reference values, that is in the area of normal coagulation: spatial clot growth rate (V) – 26.56 (25.0; 29.2) μm/min, the time to the start of clot growth (Tlag) – 1.05 (0.85; 1.27) min, initial spatial clot growth rate (Vi) – 44.3±7.7 μm/min, stationary spatial clot growth rate (Vst) – 26.5 (24.9; 28.4) μm/min, clot size (CS) – 999.7 (912.9; 1084.7) μm, clot density (D) – 22883.1±3199.9 arb. units. D was appeared to be higher in women [22947.7 (21477.5; 22947.7) vs men [22124.8 (19722.8; 22124.8), p=0.035] and Tlag was significantly higher in patients with chronic heart failure [1.2 (1.0; 1.2) vs 1.0 (0.8; 1.0), p=0.008]. A correlation was found between level of creatinine and Tlag parameter, glomerular filtration rate (GFR) and clot density. With an increase in the level of creatinine in the blood and a decrease in GFR, respectively, there was an increase in Tlag parameter (p-value 0.038); with an increase in GFR, clot density decrease (p-value 0.005).

Conclusion. All parameters of Thrombodynamics test on residual concentration of DOACs were within reference values that indicated optimal anticoagulant effect of all DOACs. The obtained data of normal coagulation at the residual concentration of the anticoagulant are consistent with the previously obtained data on the safety and effectiveness of DOACs using other methods. Further studies with clinical end points are needed to assess the clinical value of this method.

Efficacy and safety of novel oral anticoagulants in patients with atrial nonvalvular atrial fibrillation and diabetes mellitus: a systematic review and meta-analysis

OBJECTIVE

This study incorporates the results of subgroup analyses of currently published randomized controlled trials (RCTs) and real-world cohort studies to compare the effectiveness and safety of new direct oral anticoagulants (NOACs) and warfarin among nonvalvular atrial fibrillation patients with diabetes.

METHODS

The PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov databases were searched. Five retrospective cohort studies and four subgroup analyses of RCTs were included in this meta-analysis.

RESULTS

A meta-analysis of the data of 26,7272 patients showed that for patients with nonvalvular atrial fibrillation and diabetes, NOACs can significantly reduce the incidence of stroke/systemic embolism (SSE), ischaemic stroke, and haemorrhagic stroke compared with warfarin, with no significant difference in major bleeding and all-cause mortality. Additionally, NOACs were superior to warfarin in the incidence of intracranial bleeding, gastrointestinal bleeding, myocardial infarction, and vascular death.

CONCLUSIONS

Among nonvalvular atrial fibrillation patients with diabetes, NOACs were associated with a lower risk of SSE versus warfarin, with no significant difference in major bleeding. Therefore, NOACs may be a better clinical choice.

Current Use of Oral Anticoagulation Therapy in Elderly Patients with Atrial Fibrillation: Results from an Italian Multicenter Prospective Study-The ISNEP Study

Background: Atrial fibrillation (AF) is the most common heart arrhythmia, and its prevalence increases with age. Oral Anticoagulant Therapy (OAT) with non-vitamin K antagonist oral anticoagulants (NOACs) or vitamin K antagonists (VKAs) is essential to avoid thromboembolic events in AF. However, this treatment is associated with a high risk of bleeding and low adherence in elderly patients. Aim: The aim was to evaluate the real-world use of OAT in a population of patients aged ≥80 years in twenty-three Italian centers and to investigate the tolerance of and patient satisfaction with this therapy. Methods: The ISNEP Study is a multicenter cross-sectional study enrolling patients with AF and aged ≥80 years and treated with either NOACs or VKAs. A written questionnaire was administered to each patient to evaluate the adherence to and patient satisfaction with this therapy. Results: The study included 641 patients with a mean age of 85 (82−87) years. The use of NOACs was reported in 93.0% of cases, with the remaining 7.0% treated with VKAs. A history of stroke events was reported in five (11.1%) and one (0.2%) patients in the VKA and NOAC groups, respectively. The rate of referred ecchymosis/epistaxis was significantly higher in the VKA group compared to the NOAC group (p < 0.001). Patients receiving NOACs reported a substantial improvement in their quality of life compared to the VKA group. Conclusions: A small, but not negligible, proportion of elderly AF patients is still treated with VKAs. Patients treated with NOAC have a higher level of satisfaction with the therapy and complete adherence.

Sulfonated non-saccharide molecules and human factor XIa: Enzyme inhibition and computational studies

Human factor XIa (FXIa) is a serine protease in the intrinsic coagulation pathway. FXIa has been actively targeted to develop new anticoagulants that are associated with a reduced risk of bleeding. Thousands of FXIa inhibitors have been reported, yet none has reached the clinic thus far. We describe here a novel class of sulfonated molecules that allosterically inhibit FXIa with moderate potency. A library of 18 sulfonated molecules was evaluated for the inhibition of FXIa using a chromogenic substrate hydrolysis assay. Only six molecules inhibited FXIa with IC₅₀ values of 4.6-29.5 μM. Michaelis-Menten kinetics indicated that sulfonated molecules are allosteric inhibitors of FXIa. Inhibition of FXIa by these molecules was reversed by protamine. The molecules also showed moderate anticoagulant effects in human plasma with preference to prolong activated partial thromboplastin time. Their binding to an allosteric site in the catalytic domain of FXIa was modeled to illustrate potential binding mode and potential important Arg/Lys residues. Particularly, inhibitor 16 (IC₅₀  = 4.6 µM) demonstrated good selectivity over a panel of serine proteases including those in the coagulation process. Inhibitor 16 did not significantly compromise the viability of three cell lines. Overall, the reported sulfonated molecules serve as a new platform to design selective, potent, and allosteric inhibitors of FXIa for therapeutic applications.

Safety of Non-Vitamin K Antagonist Oral Anticoagulant Treatment in Patients with Chronic Kidney Disease and Kidney Transplant Recipients

The use of novel oral anticoagulants in patients with impaired renal function or undergoing immunosuppressive therapy is limited due to the risk of drug-to-drug interactions and anticoagulation-related adverse events. This article aims to assess the current data on the safety of direct-acting oral anticoagulant-based therapy in the population of kidney transplant recipients and patients with impaired renal function. The most important factors affecting the safety of treatment are the incidence of bleeding events, thromboembolic events, deaths and drug-to-drug interactions. The available data were compared to the findings on warfarin-based anticoagulation. Findings on the use of novel oral anticoagulants in kidney transplant recipients are limited yet promising in terms of safety and efficacy of use. However, current recommendations state that the co-administration of non-vitamin K antagonist oral anticoagulants with several immunosuppressive agents is contraindicated.

[Safety and effectiveness of oral anticoagulation in patients with atrial fibrillation and renal insufficiency - a real-world perspective]

Non-vitamin-K dependent oral anti-coagulants (NOAC) are the current therapeutic standard for preventing strokes in patients with atrial fibrillation (AF) and should be preferred over vitamin K antagonists (VKA) in this indication. This recommendation applies also to patients with VHF and concomitant chronic kidney disease (CKD). Real World Evidence (RWE), i. e., structured data from clinical practice, extends and confirms the clinical evidence generated in more formalized clinical trials with NOAC and VKA. In addition, RWE in respect to the indication showed that the superiority of NOAC versus the VKA warfarin can also be extrapolated to phenprocoumon, the commonly used VKA in Germany. Furthermore, data include evidence that the typical progression of CKD appears to be less pronounced in individuals treated with NOAC compared to those treated with VKA.

Arrhythmias in Chronic Kidney Disease

Arrhythmias cause disability and an increased risk of premature death in the general population but far more so in patients with renal failure. The association between the cardiac and renal systems is complex and derives in part from common causality of renal and myocardial injury from conditions including hypertension and diabetes. In many cases, there is a causal relationship, with renal dysfunction promoting arrhythmias and arrhythmias exacerbating renal dysfunction. In this review, the authors expand on the challenges faced by cardiologists in treating common and uncommon arrhythmias in patients with renal failure using pharmacological interventions, ablation and cardiac implantable device therapies. They explore the most important interactions between heart rhythm disorders and renal dysfunction while evaluating the ways in which the coexistence of renal dysfunction and cardiac arrhythmia influences the management of both.

Safety and Efficacy of DOACs in Patients with Advanced and End-Stage Renal Disease

The prevalence of chronic kidney disease (CKD) is increasing due to the aging of the population and multiplication of risk factors, such as hypertension, arteriosclerosis and obesity. Impaired renal function increases both the risk of bleeding and thrombosis. There are two groups of orally administered drugs to prevent thromboembolic events in patients with CKD who require anticoagulation: vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs). Although VKAs remain the first-line treatment in patients with advanced CKD, treatment with VKAs is challenging due to difficulties in maintaining the appropriate anticoagulation level, tendency to accelerate vascular calcification and faster progression of CKD in patients treated with VKAs. On the other hand, the pleiotropic effect of DOACs, including vascular protection and anti-inflammatory properties along with comparable efficacy and safety of treatment with DOACs, compared to VKAs observed in preliminary reports encourages the use of DOACs in patients with CKD. This review summarizes the available data on the efficacy and safety of DOACs in patients with CKD and provides recommendations regarding the choice of the optimal drug and dosage depending on the CKD stage.

Impact of Renal Function on Effectiveness and Safety Associated With Low Dose Dabigatran in Non-valve Atrial Fibrillation Patients After Catheter Ablation

Aim: The purpose of this study is to compare the effectiveness and safety of 110 mg dabigatran in non-valve atrial fibrillation (NVAF) patients with different eGFRs.

Methods: We conducted a single-center retrospective cohort study to investigate the effectiveness and safety of 110 mg dabigatran for NVAF patients between January 2017 and December 2018 based on the eGFR category.

Results: A total of 560 NVAF patients who treated with 110 mg dabigatran were included for analysis. In 12 months, the Kaplan-Meier survival curves indicated that the lower eGFR subgroups were more likely to experience thrombosis, bleeding, and cumulative events earlier (P = 0.021 for thrombosis; P = 0.026 for bleeding; P = 0.001 for cumulative events). Gastrointestinal bleeding occurred more frequently in the moderate group than in other groups (6.94% in the moderate group vs. 1.54% in the mild group vs. 1.22% in the normal group, P = 0.028). By multivariate analysis, chronic kidney disease (P = 0.043; OR = 4.273, 95% CI 1.043–17.543) and diabetes mellitus (P = 0.023; OR = 2.194, 95% CI 1.114–4.323) were independent predictors of the composite endpoints. A positive linear relationship was observed between eGFR levels and occurrence rate of thrombosis and bleeding under anticoagulation patients with 110 mg dabigatran (R² = 0.432 and R² = 0.784, respectively).

Conclusions: Impaired renal function was associated with decreased safety and increased thrombosis risks in NVAF patients taking low dose dabigatran.

Non-valvular Atrial Fibrillation in CKD: Role of Vitamin K Antagonists and Direct Oral Anticoagulants. A Narrative Review

Atrial fibrillation (AF) is the most common arrhythmia in chronic kidney disease (CKD), with a close bidirectional relationship between the two entities. The presence of CKD in AF increases the risk of thromboembolic events, mortality and bleeding. Vitamin K antagonists (VKA) have been the mainstay of treatment for the prevention of thromboembolic events in AF until recently, with confirmed benefits in AF patients with stage 3 CKD. However, the risk-benefit profile of VKA in patients with AF and stages 4-5 CKD is controversial due to the lack of evidence from randomized controlled trials. Treatment with VKA in CKD patients has been associated with conditions such as poorer anticoagulation quality, increased risk of bleeding, faster progression of vascular/valvular calcification and higher risk of calciphylaxis. Direct oral anticoagulants (DOACs) have shown equal or greater efficacy in stroke/systemic embolism prevention, and a better safety profile than VKA in post-hoc analysis of the pivotal randomized controlled trials in patients with non-valvular AF and stage 3 CKD, yet evidence of its risk-benefit profile in more advanced stages of CKD is scarce. Observational studies associate DOACs with a good safety/effectiveness profile compared to VKA in non-dialysis CKD patients. Further, DOACs have been associated with a lower risk of acute kidney injury and CKD development/progression than VKA. This narrative review summarizes the evidence of the efficacy and safety of warfarin and DOACs in patients with AF at different CKD stages, as well as their effects on renal function, vascular/valvular calcification and bone health.

Safety and Efficacy of Vitamin K Antagonists versus Rivaroxaban in Hemodialysis Patients with Atrial Fibrillation: A Multicenter Randomized Controlled Trial

BACKGROUND

In patients with normal renal function or early stage CKD, the risk-benefit profile of direct oral anticoagulants (DOACs) is superior to that of vitamin K antagonists (VKAs). In patients on hemodialysis, the comparative efficacy and safety of DOACs versus VKAs are unknown.

METHODS

In the Valkyrie study, 132 patients on hemodialysis with atrial fibrillation were randomized to a VKA with a target INR of 2-3, 10 mg rivaroxaban daily, or rivaroxaban and vitamin K2 for 18 months. Patients continued the originally assigned treatment and follow-up was extended for at least an additional 18 months. The primary efficacy end point was a composite of fatal and nonfatal cardiovascular events. Secondary efficacy end points were individual components of the composite outcome and all-cause death. Safety end points were life-threatening, major, and minor bleeding.

RESULTS

Median (IQR) follow-up was 1.88 (1.01-3.38) years. Premature, permanent discontinuation of anticoagulation occurred in 25% of patients. The primary end point occurred at a rate of 63.8 per 100 person-years in the VKA group, 26.2 per 100 person-years in the rivaroxaban group, and 21.4 per 100 person-years in the rivaroxaban and vitamin K2 group. The estimated competing risk-adjusted hazard ratio for the primary end point was 0.41 (95% CI, 0.25 to 0.68; P=0.0006) in the rivaroxaban group and 0.34 (95% CI, 0.19 to 0.61; P=0.0003) in the rivaroxaban and vitamin K2 group, compared with the VKA group. Death from any cause, cardiac death, and risk of stroke were not different between the treatment arms, but symptomatic limb ischemia occurred significantly less frequently with rivaroxaban than with VKA. After adjustment for competing risk of death, the hazard ratio for life-threatening and major bleeding compared with the VKA group was 0.39 (95% CI, 0.17 to 0.90; P=0.03) in the rivaroxaban group, 0.48 (95% CI, 0.22 to 1.08; P=0.08) in the rivaroxaban and vitamin K2 group and 0.44 (95% CI, 0.23 to 0.85; P=0.02) in the pooled rivaroxaban groups.

CONCLUSIONS

In patients on hemodialysis with atrial fibrillation, a reduced dose of rivaroxaban significantly decreased the composite outcome of fatal and nonfatal cardiovascular events and major bleeding complications compared with VKA.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Oral Anticoagulation in Hemodialysis, NCT03799822.

[Interdisciplinary aspects of oral anticoagulation with NOACs in atrial fibrillation]

Stroke prophylaxis with non-vitamin K-dependent oral anticoagulants (NOAKs) in patients with non-valvular atrial fibrillation (nvVHF) is now firmly established in routine clinical practice. The definition of nvVHF includes the absence of a mechanical heart valve and AF not associated with moderate- or high-grade mitral valve stenosis. The management of oral anticoagulation (OAC) requires a high degree of interdisciplinarity. Not least for this reason, uncertainties are repeatedly observed in practice, which can have far-reaching consequences for the individual patient. For this reason, a committee consisting of representatives from general medicine, geriatrics, cardiology, nephrology and neurology has gathered to identify aspects of practical relevance from the various disciplines and to jointly develop practical guidelines to improve therapy safety for patients in everyday life.

Background characteristics and anticoagulant usage patterns of elderly non-valvular atrial fibrillation patients in the ANAFIE registry: a prospective, multicentre, observational cohort study in Japan

OBJECTIVE

To explore anticoagulant usage patterns stratified by stroke and bleeding risk in elderly patients with non-valvular atrial fibrillation (NVAF).

DESIGN

Prospective, multicentre, observational cohort study.

SETTING

The real-world All Nippon AF In the Elderly (ANAFIE) registry.

PARTICIPANTS

Japanese patients aged ≥75 years with NVAF (n=32 726).

OUTCOME MEASURES

The distribution of stroke and bleeding risk scores, and the selection of anticoagulant regimen for patients at high stroke and bleeding risk.

RESULTS

Overall, 18 185 (55.6%) patients had a high risk of stroke (CHADS₂ score ≥3). Of these, 12 561 (38.4% of the total ANAFIE population) had a low bleeding risk (HAS-BLED ≤2) and 5624 (17.2%) had a high bleeding risk (HAS-BLED ≥3). Significant differences were noted between the high versus low bleeding risk groups in sex, height, weight, systolic blood pressure and rates of abnormality of lipid metabolism, gastrointestinal disease, cerebrovascular disorders, chronic kidney disease, angina pectoris, respiratory disease, primary malignant tumour, dementia and fall history within the past year (all p<0.0001). Patients with high stroke and bleeding risks had a lower anticoagulant usage rate versus the low bleeding risk group, and 8.7% and 5.8%, respectively, were not receiving any anticoagulant (p<0.0001). Patients in the high bleeding risk group had a higher usage of warfarin versus the low bleeding risk group (p<0.0001); more patients (14.0%) in the high bleeding risk group receiving warfarin had time in the therapeutic range <40%, versus those in the low bleeding risk group (11.6%, p=0.0146). Direct-acting oral anticoagulants (DOACs) were used less in the high bleeding risk group, without notable differences in the DOAC dose distribution between the two groups.

CONCLUSIONS

In elderly NVAF patients at high stroke risk, significant demographic and clinical differences were observed according to bleeding risk. Administration of low-dose DOACs was frequent, but the dose distribution was unaffected by bleeding risk.

TRIAL REGISTRATION NUMBER

UMIN000024006 (http://www.umin.ac.jp/).

Real-World Data on Characteristics and Management of Community Patients Receiving Anticoagulation Therapy Who Presented with Acute Bleeding to the Emergency Department at a Regional Australian Hospital: A Prospective Observational Study

Objective

To study patients receiving anticoagulants with or without antiplatelet therapy presenting at a regional Australian hospital with bleeding. The main aims are to explore: (1) patients' characteristics and management provided; (2) association between the type of anticoagulant and antiplatelet agent used and the requirement of reversal; (3) and the length of hospital stay (LoS) in conjunction with bleeding episode and management.

Methods

A prospective cross-sectional review of medical records of all patients who presented at a tertiary referral centre with bleeding while receiving anticoagulation therapy between January 2016 and June 2018. Data included: patients, demographics, investigations (kidney and liver function tests, coagulation profile, FBC), LoS, bleeding site, type of and reason for anticoagulation therapy, and management provided. Data analysis included descriptive statistics, χ² association, and regression models.

Results

Among the 144 eligible patients, 75 (52.1%) were male, and the mean age was 76 years (SD=11.1). Gastrointestinal tract bleeding was the most common (n=48, 33.3%), followed by epistaxis (n=32, 22.2%). Atrial fibrillation was the commonest reason for anticoagulation therapy (n=65, 45.1%). Warfarin was commonly used (n=74, 51.4%), followed by aspirin (n=29, 20.1%), rivaroxaban (n=26, 18.1%), and apixaban (n=12, 8.3%). The majority had increased blood urea nitrogen (n=67, 46.5%), while 58 (40.3%) had an elevated serum creatinine level, and 59 (41.0%) had a mild reduction in eGFR. Thirty-five of the warfarinised patients (47.3%) had an INR above their condition's target range despite normal liver function. Severe anaemia (Hb<80g/L) was reported in 88 patients (61.1%). DOACs were associated with a reduced likelihood of receiving reversal (B= -1.7, P=<.001), and with a shorter LoS (B= -4.1, P=.046) when compared with warfarin, LMWH, and antiplatelet therapy.

Conclusion

Warfarin use was common among patients who presented with acute bleeding, and the INR in many warfarinised patients exceeded the target for their condition. DOACs were associated with a reduced likelihood of receiving reversal and a shorter LoS than warfarin, LMWH, which might support a broader application of DOACs into community practice.

Effect of Rivaroxaban or Apixaban in Atrial Fibrillation Patients with Stage 4-5 Chronic Kidney Disease or on Dialysis

BACKGROUND

Anticoagulant treatment in non-valvular atrial fibrillation (AF) patients with severe chronic kidney disease (CKD) or on dialysis remains a matter of debate. The object of this study was to quantify the benefit-risk profiles of rivaroxaban or apixaban versus warfarin in AF patients with stage 4-5 CKD or on dialysis.

METHOD

A comprehensive search of the Cochrane Library, PubMed, Ovid, and Google Scholar databases was performed for eligible studies that comparing the effect and safety of rivaroxaban or apixaban versus warfarin in AF patients with stage 4-5 CKD or on dialysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were abstracted, and then pooled using a random-effects model.

RESULTS

A total of seven studies, one post hoc analysis of RCT and six observational cohorts, were included in this meta-analysis. Compared with warfarin use, the use of rivaroxaban or apixaban was significantly associated with reduced risks of all-cause death (HR = 0.82, 95% CI 0.72-0.93) and gastrointestinal bleeding (HR = 0.87, 95% CI 0.80-0.95). There were no significant differences in the risks of stroke or systemic embolism (rivaroxaban, HR = 0.71, 95% CI 0.43-1.19; apixaban, HR = 0.86, 95%CI 0.68-1.09) and major bleeding (rivaroxaban, HR = 0.96, 95% CI 0.64-1.45; apixaban, HR = 0.56, 95%CI 0.28-1.12).

CONCLUSIONS

Current evidence suggests that rivaroxaban or apixaban are safe and at least as effective as warfarin in patients with AF and stage 4-5 CKD or on dialysis.

Relationship between the degree of renal dysfunction and the safety and efficacy outcomes in patients with atrial fibrillation receiving direct oral anticoagulants

BACKGROUND

The clinical evaluation of a direct oral anticoagulant (DOAC) treatment for atrial fibrillation (AF) patients with renal dysfunction has not been sufficiently studied. This study aimed to evaluate the safety and efficacy of DOACs for patients with a severely impaired renal function.

METHODS

This was a retrospective and observational study in a single center. We enrolled 894 consecutive AF patients who were prescribed DOACs, and divided them into three groups based on their creatinine clearance (CrCl) value: CrCl ≥ 50 mL/min group (n = 634), CrCl 30-49 mL/min group (n = 207), and CrCl 15-29 mL/min group (n = 53). We evaluated the occurrence of major bleeding (MB) as the safety outcome and thromboembolic events (TEs) as the efficacy outcome during the follow-up.

RESULTS

The incidence of MB in the CrCl 15-29 mL/min group was significantly higher than in the other groups (CrCl ≥ 50 mL/min group, 0.8/100 person-years; CrCl 30-49 mL/min group, 1.2/100 person-years; CrCl 15-29 mL/min group, 9.0/100 person-years, log rank test, P < .001). On the other hand, there was no significant difference in the incidence of TEs among the three groups. A multivariate analysis using a Cox proportional hazard model adjusted for the age revealed that the CrCl 15-29 mL/min group was significantly associated with increased MB compared to the CrCl ≥ 50 mL/min group (hazard ratio: 9.76, 95% confidence interval: 2.69-35.5, P < .001). Similar results were observed when adjusting for other multiple clinical factors.

CONCLUSION

This study demonstrated that the degree of renal dysfunction was a significant prognostic factor for MB in AF patients receiving DOACs.

Pharmacokinetics and dialytic clearance of apixaban during in vitro continuous renal replacement therapy

Background

To evaluate the transmembrane clearance (CL_TM) of apixaban during modeled in vitro continuous renal replacement therapy (CRRT), assess protein binding and circuit adsorption, and provide initial dosing recommendations.

Methods

Apixaban was added to the CRRT circuit and serial pre-filter bovine blood samples were collected along with post-filter blood and effluent samples. All experiments were performed in duplicate using continuous veno-venous hemofiltration (CVVH) and hemodialysis (CVVHD) modes, with varying filter types, flow rates, and point of CVVH replacement fluid dilution. Concentrations of apixaban and urea were quantified via liquid chromatography-tandem mass spectrometry. Plasma pharmacokinetic parameters for apixaban were estimated via noncompartmental analysis. CL_TM was calculated via the estimated area under the curve (AUC) and by the product of the sieving/saturation coefficient (SC/SA) and flow rate. Two and three-way analysis of variance (ANOVA) models were built to assess the effects of mode, filter type, flow rate, and point of dilution on CL_TM by each method. Optimal doses were suggested by matching the AUC observed in vitro to the systemic exposure demonstrated in Phase 2/3 studies of apixaban. Linear regression was utilized to provide dosing estimations for flow rates from 0.5–5 L/h.

Results

Mean adsorption to the HF1400 and M150 filters differed significantly at 38 and 13%, respectively, while mean (± standard deviation, SD) percent protein binding was 70.81 ± 0.01%. Effect of CVVH point of dilution did not differ across filter types, although CL_TM was consistently significantly higher during CRRT with the HF1400 filter compared to the M150. The three-way ANOVA demonstrated improved fit when CL_TM values calculated by AUC were used (adjusted R² 0.87 vs. 0.52), and therefore, these values were used to generate optimal dosing recommendations. Linear regression revealed significant effects of filter type and flow rate on CL_TM by AUC, suggesting doses of 2.5–7.5 mg twice daily (BID) may be needed for flow rates ranging from 0.5–5 L/h, respectively.

Conclusion

For CRRT flow rates most commonly employed in clinical practice, the standard labeled 5 mg BID dose of apixaban is predicted to achieve target systemic exposure thresholds. The safety and efficacy of these proposed dosing regimens warrants further investigation in clinical studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02248-7.

Ten years of non-vitamin K antagonists oral anticoagulants for stroke prevention in atrial fibrillation: is warfarin obsolete?

Currently, four non-vitamin K antagonists oral anticoagulants (NOACs) are available for stroke prevention in atrial fibrillation (AF). These have been in clinical use for up to 10 years now. Besides data of the initial phase III clinical trials, now clinical data, several sub-studies, meta-analyses, and studies in special clinical settings and specific patient populations are available. This review shall give an overview on the history of NOAC development, sum up study data and ‘real-world’ clinical data as well as discuss several special clinical settings like NOAC treatment in patients that require coronary artery stenting or cardioversion (CV). Furthermore, treatment considerations in special patient populations like patients with renal impairment, obesity, or patients requiring NOACs for secondary prevention are discussed. The significance of NOAC treatment will be discussed under consideration of the recently published 2020 ESC/EACTS Guidelines for the diagnosis and management of AF.

[Safety performance of rivaroxaban versus warfarin in patients with atrial fibrillation and advanced chro-nic kidney disease]

Aim To evaluate safety of using rivaroxaban in patients with stage 4 chronic kidney disease (CKD) or transient, stable decline of glomerular filtration rate (GFR) to 15-29 ml /min / 1.73 m2 in the presence of atrial fibrillation (AF).Material and methods This multicenter prospective, randomized study included patients admitted to cardiology departments from 2017 through 2019. Of 10 224 admitted patients 109 (3 %) patients with AF and stage 4 CKD or a stable decline of GFR to 15-29 ml /min / 1.73 m2 were randomized at 2:1 ratio to the rivaroxaban 15 mg /day (n=73) treatment group or to the warfarin treatment group (n=36). The primary endpoint was development of BARC and ISTH major, minor, and clinically relevant minor bleeding. Mean follow-up duration was 18 months.Results Patients receiving warfarin had a significantly higher incidence of BARC (n=26 (72.2 %) vs. n=31 (42.4 %), р&lt;0.01) and ISTH (n=22 (61.1 %) vs. n=27 (36.9 %), p&lt;0.01) minor bleeding and all ISTH clinically relevant (minor clinically relevant and major bleedings) n=10 (27.7 %) vs. n=8 (10.9 %), р=0.03]. The number of repeated hospitalizations was 65 (43% of patients) in the rivaroxaban treatment group and 27 (48% of patients) in the warfarin treatment group (р=0.57), including 24 (36.9 %) and 11 (40.7 %) emergency admissions in the rivaroxaban and warfarin treatment groups, respectively (р=0.96). Significant improvement of changes in creatinine clearance and GFR (by CKD-EPI and Cockroft-Gault) was observed in the rivaroxaban treatment group.Conclusion The study provided evidence for a more beneficial safety profile of rivaroxaban compared to warfarin in patients with AF and advanced CKD.

Position paper on the safety/efficacy profile of direct oral anticoagulants in patients with chronic kidney disease. Consensus document from the SIN, FCSA and SISET

Direct oral anticoagulants (DOAC) are mostly prescribed to prevent cardioembolic stroke in patients with non-valvular atrial fibrillation (AF). An increasing number of guidelines recommend DOAC in AF patients with preserved renal function for the prevention of thromboembolism, and an increased use of DOAC in daily practice has been recorded also in elderly patients. Ageing is associated with a reduction in glomerular filtration rate, and impaired renal function, regardless of the cause, increases the risk of bleeding. Multiple medication use (polypharmacy) for treating superimposed co-morbidities is common in both elderly and chronic kidney disease (CKD) patients and drug-drug interaction may cause accumulation of DOAC, thereby increasing the risk of bleeding. The safety profile of DOAC in patients with CKD has not been defined with any certainty, particularly in those with severely impaired renal function or end stage renal disease. This has been due to the heterogeneity of studies and the relative paucity of data. This document reports the position of three Italian scientific societies engaged in the management of patients with atrial fibrillation who are treated with DOAC and present with CKD.

Position paper on the safety/efficacy profile of Direct Oral Anticoagulants in patients with Chronic Kidney Disease: Consensus document of Società Italiana di Nefrologia (SIN), Federazione Centri per la diagnosi della trombosi e la Sorveglianza delle terapie Antitrombotiche (FCSA) and Società Italiana per lo Studio dell'Emostasi e della Trombosi (SISET)

Direct oral anticoagulants (DOAC) are mostly prescribed to prevent cardioembolic stroke in patients with non-valvular atrial fibrillation (AF). An increasing number of guidelines recommend DOAC in AF patients with preserved renal function for the prevention of thromboembolism and an increased use of DOAC in daily practice is recorded also in elderly patients. Aging is associated with a reduction of glomerular filtration rate and impaired renal function, regardless of the cause, increases the risk of bleeding. Multiple medication use (polypharmacy) for treating superimposed co-morbidities is common in both elderly and chronic kidney disease (CKD) patients and drug-drug interaction may cause accumulation of DOAC, thereby increasing the risk of bleeding. There is uncertainty on the safety profile of DOAC in patients with CKD, particularly in those with severely impaired renal function or end stage renal disease, due to the heterogeneity of studies and the relative paucity of data. This document reports the position of three Italian scientific societies engaged in the management of patients with atrial fibrillation who are treated with DOAC and present with CKD.

Increased Incident Ischemic Stroke Risk in Advanced Kidney Disease: A Large-Scale Real-World Data Study

INTRODUCTION

Evidence using real-world data is sparse regarding the effects of oral anticoagulants (OACs) among patients with kidney disease. The aim of this study was to investigate the effects of kidney disease on ischemic stroke (IS) or systemic embolism (SE) among patients taking OAC, using large-scale real-world data in Japan.

METHODS

This was a retrospective cohort study using claims data and health checkup data from health insurance associations in Japan, from January 2005 to June 2017. We enrolled 21,581 patients diagnosed with atrial fibrillation (AF). Of the total population, 11,848 (54.9%) patients were taking OAC. A Cox proportional hazards model was used to examine the effect of kidney disease on IS/SE with or without OAC.

RESULTS

During follow-up, 208 participants who were not taking OAC (mean follow-up 2.6 years) and 200 who were taking OAC (mean follow-up 3.0 years) experienced IS/SE. The % IS/SE incidence rates with and without kidney disease were 2.42/person-year and 0.63/person-year in the total population, 3.66/person-year and 0.76/person-year in the group without OAC use, and 1.52/person-year and 0.55/person-year in patients with OAC use, respectively. Hazard ratios (HRs) and 95% confidence intervals (CIs) of kidney disease for IS/SE were high, irrespective of OAC, even after adjustment: adjusted HR 2.62 (95% CI: 1.72-3.99) without OAC and adjusted HR 2.03 (95% CI: 1.20-3.44) with OAC; p = 0.193 for interaction between no OAC and OAC. Although bleeding risk was also high for kidney disease irrespective of OAC use (HR 2.93 [95% CI: 2.27-3.77] in the total population, HR 3.08 [95% CI: 2.15-4.43] in the group without OAC, and HR 2.73 [95% CI: 1.90-3.91] in the group with OAC use), net clinical benefit indicated that the benefit of OAC use exceeded the risk of bleeding: HR 4.50 (95% CI: 0.76-8.23) among those with kidney disease and HR 0.35 (95% CI: 0.04-0.66) among those without kidney disease.

CONCLUSION

Although we found that OAC use was effective and recommended for patients with AF, advanced kidney disease is still an independent risk factor for IS/SE, even in patients taking OAC. Physicians should be aware of this risk and strictly control modifiable risk factors, regardless of OAC use.

Ischemic stroke and dose adjustment of oral Factor Xa inhibitors in patients with atrial fibrillation

BACKGROUND

Oral Factor Xa inhibitors for the prevention of stroke in atrial fibrillation require dose adjustment based on certain clinical criteria, but the off-label use of the reduced doses is common.

METHODS

Data from an observational registry including patients admitted with acute cerebral ischemia while taking oral Factor Xa inhibitors for atrial fibrillation between April 2016 and December 2018 were investigated. The dose regimen of the Xa inhibitor was classified as "appropriate", "underdosed" and "overdosed" in conformity with the European Medicines Agency labelling. The effect of underdosing on the functional factor Xa plasma level on admission, the clinical stroke severity and the functional outcome after 3 months were investigated.

RESULTS

254 patients with cerebral ischemia while on Factor Xa inhibitors were included. The dose regimen of the Factor Xa inhibitor was appropriate in 166 patients (65%), underdosed in 67 patients (26%) and overdosed in 21 patients (8%). Underdosing was associated with female sex, diabetes mellitus and higher CHA₂DS₂-Vasc scores. Underdosing independently predicted lower anti-Xa plasma levels on admission [median 69.4 ng/ml (IQR 0.0-121.6) vs. 129.2 ng/ml (65.5-207.2); p < 0.001], was associated with higher NIHSS scores on admission [median 5 (IQR 1-10) vs. 3 (1-7); p = 0.041] and worse functional outcome after 3 months (favorable outcome 26.9% vs. 46.9%; p = 0.025).

CONCLUSION

One in three patients with ischemic stroke during treatment with oral Xa inhibitors used inappropriate dose regimens. Underdosing was associated with lower functional plasma levels, higher clinical stroke severity and worse functional outcome.

Role of direct oral anticoagulants in patients with kidney disease

The anticoagulation field is experiencing a renaissance that began with regulatory approval of the direct thrombin inhibitor dabigatran, a direct oral anticoagulant (DOAC), in 2010. The DOAC medication class has rapidly evolved to include the additional approval of 4 direct factor Xa inhibitors. Commensurately, DOAC use has increased and collectively account for the majority of new anticoagulant prescriptions. Despite exclusion of patients with moderate-to-severe kidney disease from most pivotal DOAC trials, DOACs are increasingly used in this setting. An advantage of DOACs is similar or improved antithrombotic efficacy with less bleeding risk when compared with traditional agents. Several post hoc analyses, retrospective studies, claims data studies, and meta-analyses suggest that these benefits extend to patients with kidney disease. However, the lack of randomized controlled trial data in specific kidney disease settings, with their unique pathophysiology, should be a call to action for the kidney community to systematically study these agents, especially because early data suggest that DOACs may pose less risk of anticoagulant-related nephropathy than do vitamin K antagonists. Most DOACs are renally cleared and are significantly protein bound in circulation; thus, the pharmacokinetics of these drugs are influenced by reduced renal function and proteinuria. DOACs are susceptible to altered metabolism by P-glycoprotein inhibitors and inducers, including drugs commonly used for the management of kidney disease comorbidities. We summarize the currently available literature on DOAC use in kidney disease and illustrate knowledge gaps that represent important opportunities for prospective investigation.

A synthetic heparin mimetic that allosterically inhibits factor XIa and reduces thrombosis in vivo without enhanced risk of bleeding

BACKGROUND

Human factor XIa (FXIa) is an actively pursued target for development of safer anticoagulants. Our long-standing hypothesis has been that allosterism originating from heparin-binding site(s) on coagulation enzymes is a promising approach to yield safer agents.

OBJECTIVES

To develop a synthetic heparin mimetic as an inhibitor of FXIa so as to reduce clot formation in vivo but not carry high bleeding risk.

METHODS

We employed a gamut of methods involving synthetic chemistry, biophysical biochemistry, enzyme assays, blood and plasma coagulation assays, and in vivo thrombosis models in this work.

RESULTS

Sulfated chiro-inositol (SCI), a non-saccharide mimetic of heparin, was synthesized in three steps in overall yields of >50%. SCI inhibited FXIa with potency of 280 nmol/L and preferentially engaged FXIa's heparin-binding site to conformationally alter its active site. SCI inhibition of FXIa could be rapidly reversed by common antidotes, such as protamine. SCI preferentially prolonged plasma clotting initiated with recalcification, rather than thromboplastin, alluding to its intrinsic pathway-based mechanism. Human blood thromboelastography indicated good ex vivo anticoagulation properties of SCI. Rat tail bleeding and maximum-dose-tolerated studies indicated that no major bleeding or toxicity concerns for SCI suggesting a potentially safer anticoagulation outcome. FeCl3 -induced arterial and thromboplastin-induced venous thrombosis model studies in the rat showed reduced thrombus formation by SCI at 250 μg/animal, which matched enoxaparin at 2500 μg/animal.

CONCLUSIONS

Overall, SCI is a highly promising, allosteric inhibitor of FXIa that induces potent anticoagulation in vivo. Further studies are necessary to assess SCI in animal models mimicking human clinical indications.

Clinical outcomes and treatment patterns among Medicare patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease

Background

Patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease (CKD) have increased risk of adverse outcomes. This study evaluated treatment with oral anticoagulants and outcomes in elderly NVAF patients with CKD.

Methods

Retrospective observational cohort study of US Medicare fee-for-service patients aged ≥66 years with comorbid CKD (advanced: Stage 4 and higher; less advanced: Stages 1–3) and a new NVAF diagnoses from 2011–2013. All-cause mortality, stroke, major bleeding, and myocardial infarction rates were estimated for 1 year post-NVAF diagnosis. Associations between CKD stage and outcomes were evaluated with multivariate-adjusted Cox regression. We assessed oral anticoagulant (OAC) receipt within 90 days post-NVAF diagnosis and associations between OAC receipt and outcomes.

Results

There were 198,380 eligible patients (79,681 with advanced CKD). After adjustment for age, gender, and comorbidities, advanced CKD was associated with increased mortality (Stage 5 HR 1.47; 95% CI 1.42–1.52), MI (HR 1.48; 95% CI 1.33–1.64), stroke (HR 1.23; 95% CI 1.11–1.37) and major bleed (HR 1.44; 95% CI 1.36–1.53) risks. Among Medicare Part D enrollees who survived ≥90 days post-NVAF diagnosis, 65–71% received no OACs in the first 90 days. Those receiving warfarin (HR 0.73; 95% CI 0.71–0.75) or DOACs (HR 0.52; 95% CI 0.49–0.56) within the first 90 days had reduced mortality in the period 90 days to 1 year following NVAF diagnosis compared to those without.

Conclusion

Elderly NVAF patients with advanced CKD (Stage 4 or higher) had higher mortality risks and serious clinical outcomes than those with less advanced CKD (Stage 1–3). OAC use was low across all CKD stages, but was associated with a lower mortality risk than no OAC use in the first year post-NVAF diagnosis.

Non-vitamin K antagonist oral anticoagulants vs. vitamin-K antagonists in patients with atrial fibrillation and chronic kidney disease: a nationwide cohort study

Background

We aimed to compare effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) versus vitamin-K antagonists (VKA) in atrial fibrillation (AF) patients with chronic kidney disease (CKD) not receiving dialysis.

Methods

By using personal identification numbers, we cross-linked individual-level data from Danish administrative registries. We identified every citizen with a prior diagnosis of AF and CKD who initiated NOAC or VKA (2011–2017). An external analysis of 727 AF patients with CKD (no dialysis) was performed to demonstrate level of kidney function in a comparable population. Study outcomes included incidents of stroke/thromboembolisms (TEs), major bleedings, myocardial infarctions (MIs), and all-cause mortality. We used Cox proportional hazards models to determine associations between oral anticoagulant treatment and outcomes.

Results

Of 1560 patients included, 1008 (64.6%) initiated VKA and 552 (35.4%) initiated NOAC. In a comparable population we found that 95.3% of the patients had an estimated glomerular filtration rate (eGFR) < 59 mL/min. Patients treated with NOAC had a significantly decreased risk of major bleeding (hazard ratio (HR): 0.47, 95% confidence interval (CI): 0.26–0.84) compared to VKA. There was not found a significant association between type of anticoagulant and risk of stroke/TE (HR: 0.83, 95% CI: 0.39–1.78), MI (HR: 0.45, 95% CI: 0.18–1.11), or all-cause mortality (HR: 0.99, 95% CI: 0.77–1.26).

Conclusion

NOAC was associated with a lower risk of major bleeding in patients with AF and CKD compared to VKA. No difference was found in risk of stroke/TE, MI, and all-cause mortality.

A meta-epidemiological study of subgroup analyses in cochrane systematic reviews of atrial fibrillation

BACKGROUND

Information on subgroup assessments in systematic reviews (SR) of atrial fibrillation (AF) is limited. This review aims to describe subgroup analyses in AF SRs to inform the design of SRs and randomized trials as well as clinical practice.

METHODS

We conducted a cross sectional meta-epidemiological study of Cochrane AF reviews by searching AF (including variants) in the title, abstract, or keyword field without date or language restrictions (Issue 9; September 2018). Two reviewers independently extracted study characteristics to summarize frequency of subgroups pre-specified and conducted and report credibility of subgroup effects claimed.

RESULTS

Of 39 Cochrane reviews identified, 17 met inclusion criteria (including 168 reports of 127 randomized trials) and the majority (16; 94.1%) conducted meta-analysis of outcomes. Most (13; 76.5%) planned pre-specified subgroup analyses; 7 of which (41.2%) conducted subgroups. In these 7 reviews, 56 subgroups were planned, 17 (30.4%) conducted and 6 (10.7%) yielded subgroup effects. Variables such as co-morbid disease, stroke risk factors, prior stroke/transient ischemic attack, age, race, and sex represented 44% (24 subgroups) of all planned subgroups (8 conducted; 14.3%); however, information on covariate selection was lacking. Overall, more subgroups were planned than conducted (mean difference (95% CI) 2.3 (1.2-3.5, p < 0.001)). Of all subgroups conducted, anticoagulant characteristics comprised a third of all subgroup effects (n = 5, 35.7%). The credibility of subgroups identified (n = 14) was assessed and less than half (43%) represented one of a small number of pre-specified hypothesis and rarely were effects seen within studies (7%). Of 5 reviews that reported subgroup effects, only 3 discussed subgroup effects as part of the overall conclusions; none discussed credibility of subgroup effects.

CONCLUSIONS

This meta-epidemiological review of a subset of Cochrane AF reviews suggests that planning and reporting of subgroup analyses in AF reviews can be improved to better inform clinical management. Most pre-specified subgroup analyses were not performed, important variables (such as stroke, bleeding risk, and other comorbidities) were rarely examined and credibility of subgroup effects claimed was low. Future reviews should aim to identify important subgroups in their protocols and use recommended approaches to test subgroup effects in order to better support clinical decision-making.

Atrial Fibrillation and Stroke. A Review on the Use of Vitamin K Antagonists and Novel Oral Anticoagulants

Atrial fibrillation (AF) is the most common arrhythmia, ranging from 0.1% in patients <55 years to >9% in octogenarian patients. One important issue is represented by the 5-fold increased ischemic stroke risk in AF patients. Hence, the role of anticoagulation is central. Until a few years ago, vitamin K antagonists (VKAs) and low molecular weight heparin represented the only option to prevent thromboembolisms, though with risks. Novel oral anticoagulants (NOACs) have radically changed the management of AF patients, improving both life expectancy and life quality. This review aims to summarize the most recent literature on the use of VKAs and NOACs in AF, in light of the new findings.

Safety of Using Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Chronic Kidney Disease

The purpose of this review is to examine the possibilities and prospects for the use of direct oral anticoagulants for the prevention of thromboembolic complications in patients with atrial fibrillation and chronic kidney disease. Chronic kidney disease is an independent risk factor for cardiovascular complications. Atrial fibrillation is associated with a higher risk of developing chronic kidney disease and more rapid progression of existing renal pathology. The presence of chronic kidney disease in atrial fibrillation on the one hand leads to an increased risk of thromboembolism, and on the other to an increased risk of bleeding when using anticoagulants. The standard for the prevention of thromboembolic complications in atrial fibrillation, including those with concomitant renal pathology, was considered warfarin for many years. However, modern studies have shown that the use of warfarin may enhance vascular calcification in patients with chronic kidney disease, which in turn may lead to an increased risk of ischemic strokes.

Analyzing clinical recommendations, randomized studies, meta-analyzes and a systematic review on the use of anticoagulants in patients with atrial fibrillation and renal pathology, revealed the advantage of using direct oral anticoagulants over warfarin at stage 1-3 of chronic kidney disease. Data on the use of direct oral anticoagulants with a more pronounced renal dysfunction and in patients on dialysis is limited due to the lack of a sufficient number of large randomized studies. Due to the presence of renal clearance in all oral anticoagulants, their pharmacokinetics changes to some extent with a decrease in the glomerular filtration rate, which requires dose adjustment of drugs depending on creatinine clearance. Therefore, the use of anticoagulants for the prevention of thromboembolic complications during atrial fibrillation requires special attention in patients with chronic kidney disease.

Demystifying the Benefits and Harms of Anticoagulation for Atrial Fibrillation in Chronic Kidney Disease

Patients with CKD represent a vulnerable population where the risks of atrial fibrillation, ischemic stroke, and bleeding are all heightened. Although large randomized, controlled trials in the general population clearly demonstrate that the benefits of warfarin and direct-acting oral anticoagulants outweigh the risks of bleeding, no such studies have been conducted in patients when their creatinine clearance falls below 25-30 ml/min. Without randomized, controlled trial data, the role of anticoagulation in patients with CKD with atrial fibrillation remains unclear and our practice is informed by a growing body of imperfect literature such as observational and pharmacokinetic studies. This article aims to present a contemporary literature review of the benefits versus harms of anticoagulation in atrial fibrillation for patients with CKD stages 3, 4, 5, and 5 on dialysis. Although unanswered questions and areas of clinical equipoise remain, this piece serves to assist physicians in interpreting the complex body of literature and applying it to their clinical care.

Cause-Specific Mortality in Patients with Chronic Kidney Disease and Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with death in patients with chronic kidney disease (CKD). We examined the associations between AF and cause-specific mortality in a large CKD population.

METHODS

We included 62,459 patients with estimated glomerular filtration rate 15-59 mL/min/1.73 m2 (6,639 patients with AF and 55,820 without AF) followed in a large health care system. Outcomes included overall and cause-specific deaths (a) cardiovascular; (b) malignancy; and (c) non-cardiovascular/non-malignancy causes. Cox regression models for overall mortality and separate competing risk models for each major cause of death category were used to evaluate their respective associations with AF.

RESULTS

During a median follow-up of 4.1 years, 19,094 patients died; cause of death was known for 18,854 patients. After multivariable adjustment (demographics, comorbidities, relevant laboratory data, medication use, and kidney function), AF was associated with 23% (95% CI 18-29%) higher risk of all-cause mortality, 45% (95% CI 31-61%) higher risk of cardiovascular mortality and 13% (95% CI 3-22%) lower risk of malignancy-related mortality. Exclusion of patients with malignancy yielded similar results except for a lack of association between AF and malignancy-related deaths. Results were consistent across various stages of CKD.

CONCLUSIONS

In a non-dialysis-dependent CKD population, the presence of AF was associated with higher all-cause and cardiovascular mortality. These data suggest that patients with both CKD and AF are at high cardiovascular risk, and thus clinical practice (or trials) should aim at reducing the overall excess cardiovascular mortality (not stroke alone) in patients with AF and CKD.

Multiple spontaneous hemorrhages after commencing warfarin therapy

A 94 year-old Japanese woman with renal dysfunction was admitted to our hospital for congestive heart failure caused by atrial fibrillation with rapid ventricular response. Considering the risk of stroke, warfarin was commenced. However, she developed shock following brachial and retroperitoneal hemorrhage 4 days after starting warfarin despite not being over-anticoagulated. She recovered after receiving blood transfusion and intravenous vitamin K2. Bleeding during warfarin administration occurs more frequently in older individuals with lower glomerular filtration rates, especially within the first 30 days of warfarin treatment. Physicians should therefore check for unexpected bleeding after commencing warfarin and be prepared to reverse anticoagulation.

Clinical Pharmacology of Oral Anticoagulants in Patients with Kidney Disease

Oral anticoagulants are commonly used drugs in patients with CKD and patients with ESKD to treat atrial fibrillation to reduce stroke and systemic embolism. Some of these drugs are used to treat or prevent deep venous thrombosis and pulmonary embolism in patients with CKD who undergo knee and hip replacement surgeries. Warfarin is the only anticoagulant that is approved for use by the Food and Drug Administration in individuals with mechanical heart valves. Each oral anticoagulant affects the coagulation profile in the laboratory uniquely. Warfarin and apixaban are the only anticoagulants that are Food and Drug Administration approved for use in patients with CKD and patients with ESKD. However, other oral anticoagulants are commonly used off label in this patient population. Given the acquired risk of bleeding from uremia, these drugs are known to cause increased bleeding events, hospitalization, and overall morbidity. Each anticoagulant has unique pharmacologic properties of which nephrologists need to be aware to optimally manage patients. In addition, nephrologists are increasingly asked to aid in the management of adverse bleeding events related to oral anticoagulant use in patients with CKD and patients with ESKD. This article summarizes the clinical pharmacology of these drugs and identifies knowledge gaps in the literature related to their use.

Atrial fibrillation in dialysis patients: is there a place for non-vitamin K antagonist oral anticoagulants?

Atrial fibrillation (AF) occurs approximately in 3% of general population, with greater prevalence in elderly. Non-vitamin K-dependent oral anticoagulant agents (NOACs) according to the current European guidelines are recommended for patients with AF at high risk for stroke as a first-choice treatment. NOACs are not inferior to warfarin or some of them are better than warfarin in reducing the rate of ischemic stroke. Moreover, they significantly reduce the rate of intracranial hemorrhages, major bleedings, and mortality compared with warfarin. Nevertheless according to ESC guidelines, NOACs are not recommended in patients with creatinine clearance < 30 mL/min. Observational studies provide contradictive data. Only few new trials are ongoing. Therefore, it is not clear if NOACs should be in the future prescribed to patients with advanced CKD and those on dialysis. Moreover, the risk of stroke and bleeding is much higher in such population than in patients without end-stage renal disease (ESRD). The authors provide data on pros and cons of use of NOACs in ESRD patients with AF.

Dosing challenges with direct oral anticoagulants in the elderly: a retrospective analysis

Background

Direct oral anticoagulants (DOACs) provide patients with attractive options for anticoagulation in atrial fibrillation (AF). However, dosing these agents in the elderly can be challenging due to factors such as drug interactions, reduced renal function, and less frequent monitoring. This study addressed this challenge by reviewing the dosing of three commonly used DOACs (i.e. apixaban, dabigatran, and rivaroxaban) in elderly patients managed at a pharmacist-run anticoagulation clinic.

Methods

This was a single-center, retrospective cohort study. A total of 98 cases of DOAC therapy in patients with AF aged 75 years or older receiving care at a large urban healthcare center were identified via chart review. Dosing of each DOAC was assessed at therapy initiation and throughout treatment whenever a serum creatinine was reported, using the Cockcroft-Gault equation to estimate creatinine clearance (CrCl). Dose excursions (defined as instances where patients were exposed to non-Food and Drug Administration (FDA)-approved doses) were documented in each case. Rationales for dose excursions were determined by study investigators via review of progress notes and categorized using clinical judgement.

Results

Upon therapy initiation apixaban was dosed in accordance with FDA recommendations in 92.9% of patient cases, dabigatran in 91.2% of cases, and rivaroxaban in 86.1% of cases (p = 0.70). FDA-recommended dosing was maintained throughout treatment at the highest rates with dabigatran (88.2% versus 78.6% with apixaban and 58.3% with rivaroxaban; p = 0.01, p = 0.005 for dabigatran versus rivaroxaban). The most common rationales for dose excursion were fluctuation in estimated CrCl near the dosing cutoff, and recommendations from nonpharmacist providers co-managing the patient.

Conclusions

Prescribing and maintaining FDA-recommended doses of DOAC agents in the elderly is more challenging than initially perceived. Fluctuations in renal function, comorbidities, and concomitant antiplatelet use may necessitate more individualized dosing strategies with these agents.

Direct-Acting Oral Anticoagulants as Prophylaxis Against Thromboembolism in the Nephrotic Syndrome

We report 2 cases of apixaban use as prophylaxis against thromboembolism in the nephrotic syndrome (NS), and review the existing literature on direct-acting oral anticoagulant (DOAC) use in this scenario. Our cases appear to be the first reported use of apixaban as prophylaxis against thromboembolism in NS. We report our systematic review of the existing literature on direct-acting oral anticoagulant (DOAC) use in NS, and discuss theoretical issues relevant to their therapeutic use in this clinical scenario. We searched electronic databases such as OVID, EMBASE, PubMed, and CENTRAL, DARE. The search to identify studies and the application of inclusion and exclusion criteria was performed in duplicate independently. We identified 1 pilot randomized study, 3 case reports, and 3 conference proceedings abstracts relating to DOAC use in NS. These reports all pertain to the treatment of clinically evident thrombosis in NS with rivaroxaban, edoxaban, and dabigatran rather than prophylaxis against thrombosis. Although the existing literature on DOAC use in NS is limited, initial preliminary experience appears promising.

Anticoagulation for Stroke Prevention in Older Adults with Atrial Fibrillation and Comorbidity: Current Evidence and Treatment Challenges

The burden of atrial fibrillation (AF) is projected to increase substantially over the next decade in parallel with the aging of the population. The increasing age, level of comorbidity, and polypharmacy will complicate the treatment of older adults with AF. For instance, advanced age and chronic kidney disease have been shown to increase the risk of both thromboembolism and bleeding in patients with AF. Frailty, recurrent falls and polypharmacy, while very common among elderly patients with AF, are often overlooked in the clinical decision making despite their significant interaction with oral anticoagulant (OAC) and profound impact on the patient's clinical outcomes. Such factors should be recognized, evaluated and considered in a comprehensive decision-making process. The introduction of non-vitamin K oral anticoagulants has radically changed the management of AF allowing for a more individualized selection of OAC. An understanding of the available data regarding the performance of each of the available OAC in a variety of at risk patient populations is paramount for the safe and effective management of this patient population. The aim of this review is to appraise the current evidence, point out the gaps in knowledge, and provide recommendations regarding stroke prevention in older adults with AF and comorbid conditions.

Direct oral anticoagulants versus warfarin for preventing stroke and systemic embolic events among atrial fibrillation patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is an independent risk factor for atrial fibrillation (AF), which is more prevalent among CKD patients than the general population. AF causes stroke or systemic embolism, leading to increased mortality. The conventional antithrombotic prophylaxis agent warfarin is often prescribed for the prevention of stroke, but risk of bleeding necessitates regular therapeutic monitoring. Recently developed direct oral anticoagulants (DOAC) are expected to be useful as alternatives to warfarin.

OBJECTIVES

To assess the efficacy and safety of DOAC including apixaban, dabigatran, edoxaban, and rivaroxaban versus warfarin among AF patients with CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register (up to 1 August 2017) through contact with the Information Specialist using search terms relevant to this review. Studies in the Specialised Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) which directly compared the efficacy and safety of direct oral anticoagulants (direct thrombin inhibitors or factor Xa inhibitors) with dose-adjusted warfarin for preventing stroke and systemic embolic events in non-valvular AF patients with CKD, defined as creatinine clearance (CrCl) or eGFR between 15 and 60 mL/min (CKD stage G3 and G4).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed quality, and extracted data. We calculated the risk ratio (RR) and 95% confidence intervals (95% CI) for the association between anticoagulant therapy and all strokes and systemic embolic events as the primary efficacy outcome and major bleeding events as the primary safety outcome. Confidence in the evidence was assessing using GRADE.

MAIN RESULTS

Our review included 12,545 AF participants with CKD from five studies. All participants were randomised to either DOAC (apixaban, dabigatran, edoxaban, and rivaroxaban) or dose-adjusted warfarin. Four studies used a central, interactive, automated response system for allocation concealment while the other did not specify concealment methods. Four studies were blinded while the other was partially open-label. However, given that all studies involved blinded evaluation of outcome events, we considered the risk of bias to be low. We were unable to create funnel plots due to the small number of studies, thwarting assessment of publication bias. Study duration ranged from 1.8 to 2.8 years. The large majority of participants included in this study were CKD stage G3 (12,155), and a small number were stage G4 (390). Of 12,545 participants from five studies, a total of 321 cases (2.56%) of the primary efficacy outcome occurred per year. Further, of 12,521 participants from five studies, a total of 617 cases (4.93%) of the primary safety outcome occurred per year. DOAC appeared to probably reduce the incidence of stroke and systemic embolism events (5 studies, 12,545 participants: RR 0.81, 95% CI 0.65 to 1.00; moderate certainty evidence) and to slightly reduce the incidence of major bleeding events (5 studies, 12,521 participants: RR 0.79, 95% CI 0.59 to 1.04; low certainty evidence) in comparison with warfarin.

AUTHORS' CONCLUSIONS

Our findings indicate that DOAC are as likely as warfarin to prevent all strokes and systemic embolic events without increasing risk of major bleeding events among AF patients with kidney impairment. These findings should encourage physicians to prescribe DOAC in AF patients with CKD without fear of bleeding. The major limitation is that the results of this study chiefly reflect CKD stage G3. Application of the results to CKD stage G4 patients requires additional investigation. Furthermore, we could not assess CKD stage G5 patients. Future reviews should assess participants at more advanced CKD stages. Additionally, we could not conduct detailed analyses of subgroups and sensitivity analyses due to lack of data.