Direct oral anticoagulants for stroke prevention in atrial fibrillation: treatment outcomes and dosing in special populations

Factor Xa inhibitors versus warfarin in patients with non-valvular atrial fibrillation and diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

Background

Patients with non-valvular atrial fibrillation with diabetes face increased stroke and cardiovascular risks. This study compares factor Xa inhibitors and warfarin using data from randomized controlled trials (RCTs).

Methods

MEDLINE, Embase, and Cochrane CENTRAL databases were searched for RCTs comparing the risk of efficacy and safety of any factor Xa inhibitors with dose-adjusted warfarin by diabetes status. Incidence of stroke/systemic embolism, major bleeding, intracranial hemorrhage, ischemic stroke, all-cause mortality, risk of hemorrhagic stroke, and myocardial infarction were among the outcomes of interest. A generic inverse-weighted random-effects model was used to calculate hazard ratios (HRs) with 95 percent confidence intervals (CIs).

Results

After applying exclusion criteria, four RCTs containing 19 818 patients were included in the analysis. Compared with warfarin, meta-analysis showed statistically significant reduction in incidence of stroke/systemic embolism (HR 0.80 [95% CI 0.69-0.92]; P=0.002), intracranial hemorrhage (HR 0.49 [95% CI 0.37-0.65]; P<0.001), and risk of hemorrhagic stroke (HR 0.37 [95% CI 0.20-0.66]; P=0.001) in patients on factor Xa inhibitors. However, there was no discernible difference between two treatment arms in incidence of major bleeding (HR 0.93 [95% CI 0.84-1.04]; P=0.19), ischemic stroke (risk ratio (RR) 0.90 [95% CI 0.73-1.12; P=0.34), myocardial infarction (RR 0.88 [95% CI 0.67-1.15]; P=0.35), and all-cause mortality (RR 0.89 [95% CI 0.79-1.01]; P=0.06).

Conclusion

Factor Xa inhibitors show a favorable balance between efficacy and safety compared with warfarin, which is consistent across a wide range of patients with atrial fibrillation known to be at high risk for both ischemic and bleeding events.

Efficacy and Safety of Direct Oral Anticoagulants (DOACs) Versus Warfarin in Atrial Fibrillation Patients with Prior Stroke: a Systematic Review and Meta-analysis

BACKGROUND

The purpose of this meta-analysis was to compare efficacy and safety of direct oral anticoagulants (DOACs) to warfarin for secondary stroke prevention among adult patients with atrial fibrillation and prior stroke.

METHODS

Major repositories were screened for randomized controlled trials (RCTs), RCT subgroups, and observational studies (OBSs, divided in claims and non-claims). Occurrences of ischemic stroke or transient ischemic attack, systemic embolism, all-cause mortality, intracranial hemorrhage (ICH), and major bleeding were outcomes of interest. Hazard ratios (HRs) and their confidence intervals (95%CIs) were pooled using random-effects models for each study design. Claims studies were analyzed separately from non-claims, while RCT subgroups were grouped with OBSs (non-claims) as the randomization was broken.

RESULTS

Of 8647 articles, 20 were included (one RCT, six RCT subgroups, nine claims, and four non-claims). Comparing DOACs to warfarin, pooled HRs (95%CI) were consistently in favor of DOACs although some did not reach statistical significance: for ischemic stroke, 0.84 (0.66-1.07) in claims; 0.90 (0.77-1.06) in non-claims and RCT subgroups; for systemic embolism, 0.77 (0.62-0.96) in claims; 0.86 (0.77-0.96) in non-claims and RCT subgroups; for all-cause mortality, 0.57 (0.33-0.99) in claims; 0.87 (0.79-0.96) in non-claims and RCT subgroups; for ICH, 0.72 (0.39-1.33) in claims; 0.51 (0.38-0.67) in non-claims and RCT subgroups; and for major bleeding, 0.86 (0.71-1.03) in claims; 0.90 (0.76-1.08) for non-claims and RCT subgroups.

CONCLUSION

DOACs were associated with better efficacy and safety profiles than warfarin in atrial fibrillation patients with prior stroke, more specifically a lower risk of systemic embolism, all-cause mortality, and ICH.

Efficacy and Safety of Novel Oral Anticoagulants in Atrial Fibrillation: A Systematic Review

In recent times, novel oral anticoagulants (NOACs)/direct oral anticoagulants (DOACs) have emerged as an alternative to the traditionally used Vitamin K oral antagonists (VKA) like warfarin for the treatment of atrial fibrillation (AF). This systematic review and meta-analysis aims to evaluate the efficacy and safety of NOACs in patients with AF and, thus, the related thromboembolic risks and sequelae. Of the 131 published articles we examined, 11 were included in an in-depth systematic review. The articles we reviewed were from the past ten years, from 2013 onward. The analysis derived the efficacy and safety of NOACs in patients with AF and also included different patients' baseline characteristics and subgroups. This systematic review reiterates previous research findings of superior efficacy and safety of the use of NOACs in the AF population and also illuminates certain head-to-head comparisons of individual NOACs with warfarin. It digressed into subgroups of patients with different baseline characteristics to provide evidence and support the existing guidelines for the use of NOACs in the treatment of AF. Overall, there is marked efficacy and safety of NOACs in patients with AF, be they elderly or Asian, with decreased renal function, or with other comorbidities. Adherence to NOACs was also satisfactory. Despite such a review, there needs to be more research on vast subgroups and also on reversal antidotes like andexanet alfa and idarucizumab, as well as more head-to-head analysis between NOACs over a long duration of study, which would provide more answers and pinpoint reasons as to the differences that exist between demographics and subgroups in the usage of NOACs.

The optimum anticoagulation time after endovascular thrombectomy for atrial fibrillation-related large vessel occlusion stroke: a real-world study

OBJECTIVES

To investigate the relationship between the initiation time of anticoagulation after endovascular treatment (EVT) and the outcomes in atrial fibrillation (AF)-related acute ischemic stroke (AIS) patients.

METHODS

In this prospective registry study, from March 2013 to June 2022, patients with anterior circulation territories AF-related AIS who underwent EVT within 24 h were included. The primary outcome was favorable [modified Rankin Scale (mRS) 0-1) at ninety days and the secondary outcome was hemorrhage events after anticoagulants. Factors affecting the outcomes were pooled into multivariate regression and ROC curve analysis.

RESULTS

Of 234 eligible patients, there were 63 (26.9%) patients achieved a favorable outcome. The symptomatic intracranial hemorrhage (sICH), ICH, and systemic hemorrhage events after anticoagulants occurred in 8 (3.4%), 28 (12.0%), and 39 (16.7%) patients, severally. A longer EVT to anticoagulation time (p = 0.033) was associated with an unfavorable outcome (mRS 3-6). An earlier EVT to anticoagulation time was the independent risk factor of sICH (p = 0.043), ICH (p = 0.005), and systemic hemorrhage (p = 0.005). There was no significant difference in recurrent AIS/ transient ischemic attack (TIA) or mortality among patients who started anticoagulation at ≤ 4 days, ≥ 15 days, or 4 to 15 days. The optimum cut-off for initiating anticoagulants to predict a favorable outcome and hemorrhage events was 4.5 days and 3.5 days after EVT, respectively.

CONCLUSIONS

In AF-related AIS, the time of EVT to anticoagulation is an independent factor of the functional outcome and hemorrhage events after anticoagulation. The optimal initiate time of anticoagulant after EVT is 4.5 days.

CLINICALTRIALREGISTER

NCT03754738.

Combination of platelet-to-lymphocyte ratio and D-dimer for the identification of cardiogenic cerebral embolism in non-valvular atrial fibrillation

Background

Non-valvular atrial fibrillation (NVAF) is the most common cause of cardiogenic cerebral embolism (CCE). However, the underlying mechanism between cerebral embolism and NVAF is indefinite, and there is no effective and convenient biomarker to identify potential risk of CCE in patients with NVAF in clinic. The present study aims to identify risk factors for interpreting the potential association of CCE with NVAF and providing valuable biomarkers to predict the risk of CCE for NVAF patients.

Methods

641 NVAF patients diagnosed with CCE and 284 NVAF patients without any history of stroke were recruited in the present study. Clinical data including demographic characteristics, medical history, and clinical assessments, were recorded. Meanwhile, Blood cell counts, lipid profiles, high-sensitivity C-reactive protein, and coagulation function-related indicators were measured. Least absolute shrinkage and selection operator (LASSO) regression analysis was utilized to build a composite indicator model based on the blood risk factors.

Results

(1) CCE patients had significantly increased neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), and D-dimer levels as compared with patients in the NVAF group, and these three indicators can distinguish CCE patients from ones in the NVAF group with an area under the curve (AUC) value of over 0.750, respectively. (2) Using the LASSO model, a composite indicator, i.e., the risk score, was determined based on PLR and D-dimer and displayed differential power for distinguishing CCE patients from NVAF patients with an AUC value of over 0.934. (3) The risk score was positively correlated with the National Institutes of Health Stroke Scale and CHADS2 scores in CCE patients. (4) There was a significant association between the change value of the risk score and the recurrence time of stroke in initial CCE patients.

Conclusions

The PLR and D-dimer represent an aggravated process of inflammation and thrombosis in the occurrence of CCE after NVAF. The combination of these two risk factors can contribute to identifying the risk of CCE for patients with NVAF with an accuracy of 93.4%, and the greater in change of composite indicator, the shorter in the recurrence of CCE for NVAF patients.

Clinical Associations with the differences in rivaroxaban dosing in patients with atrial fibrillation stratified by three renal function formulae

Background

Clinical trials used Cockcroft-Gault (CG) formula to calculate the estimated glomerular filtration rate (eGFR) in order to dose rivaroxaban for patients with atrial fibrillation (AF).

Objectives

The aim of this study is to evaluate rivaroxaban dosing appropriateness in patients with AF with or without renal impairment based on the CG formula and other formulae, including Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the isotope dilution mass spectrometry (IDMS) traceable Modification of Diet in Renal Disease (MDRD) Study equation and the associated clinical outcomes.

Methodology

A retrospective cohort study conducted at Sultan Qaboos University Hospital (SQUH) from 1st January 2016 to 31st December 2020, included all adult patients (≥ 18 years) treated with rivaroxaban for AF and followed up for one year after starting the treatment.

Results

Based on the CG formula, the rivaroxaban dose was inappropriately prescribed in 27% of the patients (21% overdosed and 6% underdosed). Higher baseline creatinine (P=0.0014) and concurrent use of antiplatelet therapy (P<0.001) were associated with the tendency to rivaroxaban overdosing. Higher Body Mass Index (BMI) (P=0.002), female sex (P=0.032), and CKD (P=0.003) were associated with rivaroxaban underdosing. The degree of agreement between the renal function tests when comparing MDRD vs CG and CKD-EPI vs CG in terms of estimated glomerular filtration rate/creatine clearance (eGFR/CrCl) calculation was moderate (κ=0.46) and poor (κ=0.00), respectively, while, in terms of rivaroxaban dose appropriateness was almost perfect (κ=0.82) and substantial (κ=0.77). Clinical outcomes measured by stroke and bleeding events were not significantly different according to the appropriateness of the rivaroxaban dose.

Conclusion

This study has shown a relatively high consistency with the gold standard in dosing rivaroxaban in AF patients using CG formula. Treatment efficiency and safety were not affected by the proportion of dose inappropriateness found in this cohort.

The edoxaban‐M4 metabolite and measurement of edoxaban by chromogenic assays in human plasma

Introduction

Edoxaban is the only anti-Xa inhibitor metabolized in pharmacologically active moiety that could interfere with chromogenic anti-Xa assays, especially in case of drug-drug interactions or physiological disorders.

Materials and methods

We evaluated the contribution of the main metabolite of edoxaban, edoxaban-M4 (M4), in 79 plasma samples from patients taking edoxaban. The total anti-Xa activity was evaluated on three different chromogenic factor Xa-based assays. Results were compared with a validated ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry measurement. Edoxaban and its active M4 metabolite have also been spiked separately in normal pooled plasma to assess the sensitivity of chromogenic anti-Xa assays to both molecules individually.

Results

Spiked edoxaban or M4 provided different slopes of linear regression models between chromogenic and chromatographic measurement (from 0.97 for STA Liquid Anti-Xa to 1.10 for Biophen Heparin LRT Low with edoxaban and from 0.70 for Biophen DiXaI High to 0.83 for Biophen Heparin LRT High, respectively). A positive correlation is observed between the increase of the ratio M4/edoxaban with the difference between chromogenic and chromatographic measurements.

Conclusion

Edoxaban and M4 do not similarly impact chromogenic assays, leading to biased chromogenic estimations of ponderal concentrations. In patient samples, this impact is even more important at low concentrations or in the case of an increase in the M4/edoxaban ratio because of hepatic or renal impairments or in case of drug interactions. This study highlights the limitations and risks of error of expressing results in ponderal concentrations instead of global activity anti-Xa.

Evaluation of analytic and clinical performance of thrombin-antithrombin complex and D-dimer assay in prognosis of acute ischemic stroke

: To evaluate analytic and clinical performance of plasma thrombin-antithrombin complex (TAT) and D-dimer assay in assessing the severity and outcome of acute ischemic stroke. The prospective study was conducted and extended from January 2018 to December 2018. A total of 236 patients admitted within 24 h after neurologic symptoms onset were recruited. The median TAT and D-dimer levels were significantly higher in the acute ischemic stroke patients than in the controls. The average TAT levels in patients with mild, moderately severe and severe stroke were 1.75 [interquartile ranges (IQR), 1.1-2.6], 3.3 (IQR, 1.8-4.5) and 13.5 (IQR, 7.2-15.3) ng/ml. The D-dimer levels of respective patient groups were 0.39 (IQR, 0.22-0.73), 0.58 (IQR, 0.39-1.25) and 3.59 (IQR, 1.73-4.74) mg/l. With the optimal cut-off TAT level (1.75 ng/ml) determined from receiver operating characteristic analysis, the Area under the curve (AUC), the sensitivity and specificity of TAT for stroke diagnosis were 0.763, 58.1 and 87.8%. The cut-off D-dimer level was 0.38 mg/l and the AUC, the sensitivity and specificity were 0.772, 60.2 and 88.9%. The Area under the receiver operating characteristic curves (AUROCs) and sensitivity in the moderate to severe stroke increased to 0.903 and 86.9% for TAT, and 0.880 and 80.3% for D-dimer, respectively. Age and high TAT level were significant independent risk factors for stroke severity. Age, high initial National Institutes of Health Stroke Scale score and high TAT level were significant independent poor prognostic factors on multivariate analysis. TAT and D-dimer were superior in separating the moderate-to-severe stroke than mild stroke. A high TAT plasma level is an independent predictor for stroke severity and poor prognosis during 1-month follow-up.

Non-Vitamin K Antagonist Oral Anticoagulants Versus Warfarin in Patients with Atrial Fibrillation and Peripheral Artery Disease: a Systematic Review and Meta-Analysis

BACKGROUND

The efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) compared with warfarin in patients with atrial fibrillation (AF) and peripheral artery disease (PAD) remain largely unknown. Therefore, we conducted a meta-analysis to explore the effects of NOACs versus warfarin in this population.

METHODS

We systematically searched the PubMed and Embase databases, with no linguistic restrictions, until December 2019 for relevant randomized controlled trials (RCTs) and observational studies. A random-effects model using an inverse variance method was selected to pool the risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

A total of six studies (three post hoc analyses of RCTs and three cohort studies) were included in this meta-analysis. Among AF patients treated with NOACs and warfarin, individuals with PAD had increased rates of all-cause death (RR = 1.26, 95% CI 1.07-1.48) and cardiovascular death (RR = 1.32, 95% CI 1.06-1.64) compared with those without PAD. In AF patients with PAD, we observed a similar risk of thromboembolic events, bleeding, and death with NOACs as with warfarin. In addition, there were no interactions between PAD and non-PAD subgroups regarding any of the reported outcomes of NOACs versus warfarin in AF patients (all Pinteraction > 0.05).

CONCLUSIONS

Based on current evidence, AF patients with PAD are at a higher risk of death than those without PAD. Efficacy and safety outcomes with NOACs are comparable to those with warfarin, suggesting that the use of NOACs has effects similar to warfarin in AF patients with concomitant PAD.