Effect of rivaroxaban on prothrombin fragment 1+2 compared with warfarin in patients with acute cardioembolic stroke: Insight from its serial measurement

Application of rivaroxaban in patients with non-valvular atrial fibrillation and end-stage kidney disease: A systematic review and meta-analysis

Background

Nowadays, the number of patients with non-valvular atrial fibrillation (NVAF) complicated by end-stage renal disease (ESKD) is increasing. There are significant challenges in anticoagulation with prescription drugs because of the high risk of bleeding and embolism among these patients. However, no randomized controlled trials (RCTs) of warfarin in combination with any non-vitamin K oral anticoagulant (NOACs) have been performed in patients with baseline creatinine clearance (CrCl) <25 ml/min, which makes it difficult to justify the use of anticoagulants in such patients. Then, we aimed to collect and summarize all evidence to enable the anticoagulation of rivaroxaban, which is less cleared by the kidneys, in patients with severe renal insufficiency and to complement and improve the evidence on the use of rivaroxaban for anticoagulation.

Methods

The present systematic review and meta-analysis searched the databases of PubMed, Embase, the Cochrane Library, CNKI, CBM, and Google Scholar for relevant studies from inception to 1 June 2022, with the restriction of English and Chinese. Eligible cohort studies and RCTs that reported efficacy outcomes [composite of stroke and systemic embolism (SSE), ischemic stroke (ICS), and systemic embolization] or safety outcomes [major bleeding, intracranial hemorrhage (ICH), and gastrointestinal bleeding (GIB)] of rivaroxaban in NVAF patients with ESKD were enrolled. Two authors completed the data extraction and quality assessment work, respectively. The Cochrane Collaboration tool for assessing the risk of bias was used for RCTs, and the NEW-Castle Ottawa scale was used for study quality assessment for cohort studies. Dichotomous variables were calculated as risk factors with 95% confidence intervals (CIs), and meta-analysis was performed to probe the effect of research design, rivaroxaban dose, and controlled drug factors on outcomes.

Results

In total, three studies were included for meta-analysis, involving 6,071 NVAF patients with ESKD, and two studies were included for qualitative analysis. All included studies were at low risk of bias. A meta-analysis demonstrated that mix-dose rivaroxaban caused no statistical discrepancy in the occurrence of thrombotic and bleeding events when compared to the control group (embolism, LogOR: -0.64, 95% CI: -1.05 to -0.23, P:0.25; bleeding, LogOR: -0.33, 95% CI: -0.63 to -0.03, P:0.15), and low-dose rivaroxaban produced similar results (embolism, LogOR: -1.04, 95% CI: -2.15 to 0.07, P:0.61; bleeding, LogOR: -0.81, 95% CI: -1.19 to -0.44, P:0.93).

Conclusion

In this study, low-dose rivaroxaban (10 mg, once a day) may benefit more than warfarin in patients with NVAF and ESKD.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42022330973.

The effect of rivaroxaban on biomarkers in blood and plasma: a review of preclinical and clinical evidence

Rivaroxaban is a direct, oral factor Xa inhibitor that is used for the prevention and treatment of various thromboembolic disorders. Several preclinical and clinical studies have utilized specific molecules as biomarkers to investigate the potential role of rivaroxaban beyond its anticoagulant activity and across a range of biological processes. The aim of this review is to summarize the existing evidence regarding the use of blood-based biomarkers to characterize the effects of rivaroxaban on coagulation and other pathways, including platelet activation, inflammation and endothelial effects. After a literature search using PubMed, almost 100 preclinical and clinical studies were identified that investigated the effects of rivaroxaban using molecular biomarkers. In agreement with the preclinical data, clinical studies reported a trend for reduction in the blood concentrations of D-dimers, thrombin-antithrombin complex and prothrombin fragment 1 + 2 following treatment with rivaroxaban in both healthy individuals and those with various chronic conditions. Preclinical and also some clinical studies have also reported a potential impact of rivaroxaban on the concentrations of platelet activation biomarkers (von Willebrand factor, P-selectin and thrombomodulin), endothelial activation biomarkers (matrix metalloproteinase-9, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) and inflammation biomarkers (interleukin-6, tumor necrosis factor-α and monocyte chemoattractant protein-1). Based on the results of biomarker studies, molecular biomarkers can be used in addition to traditional coagulation assays to increase the understanding of the anticoagulation effects of rivaroxaban. Moreover, there is preliminary evidence to suggest that rivaroxaban may have an impact on the biological pathways of platelet activation, endothelial activation and inflammation; however, owing to paucity of clinical data to investigate the trends reported in preclinical studies, further investigation is required to clarify these observations.

The Comparison of Therapeutic Efficacy Between Dabigatran Versus Warfarin in Patients With Nonvalvular Atrial Fibrillation

BACKGROUND

Novel oral anticoagulants and warfarin are widely used for stroke prevention in patients with atrial fibrillation. The anticoagulation status of patients receiving warfarin or rivaroxaban has been studied. In this study, we aimed to evaluate the effect of dabigatran and warfarin on preventing thrombin generation (TG).

METHODS

This retrospective study enrolled 237 nonvalvular atrial fibrillation (NVAF) subjects treated with 110 mg dabigatran etexilate twice daily and 224 NVAF patients received adjusted-dose warfarin (international normalized ratio [INR] of 2 to 3)). Coagulation assays, prothrombin fragment 1  +  2 (F1+2), calibrated automated thrombogram, and thrombin-antithrombin complex (TAT) were detected at the steady state.

RESULTS

Activated partial thromboplastin time (APTT), antithrombin III activity, fibrinogen, and lag time showed no difference between the two groups. Compared to the dabigatran group, prothrombin time and INR values were higher in the warfarin group (all P < .001). Thrombin time, endogenous thrombin potential, peak TG (Cmax), F1+2, and TAT were lower in the warfarin group. The inhibition of TG was still stronger in the warfarin group when the patients were divided into subgroups.

CONCLUSION

Conventional coagulation assays are suboptimal for assessing the coagulation status of dabigatran. TG could be used as supplementary assays to evaluate the anticoagulation effect of oral anticoagulants. Our results suggest that warfarin may inhibit TG more aggressively than dabigatran in patients regardless of age and kidney function.

Reduced Rivaroxaban Dose Versus Dual Antiplatelet Therapy After Left Atrial Appendage Closure

Background:

Percutaneous left atrial appendage closure (LAAC) exposes to the risk of device thrombosis in patients with atrial fibrillation who frequently have a contraindication to full anticoagulation. Thereby, dual antiplatelet therapy (DAPT) is usually preferred. No randomized study has evaluated nonvitamin K antagonist oral anticoagulant after LAAC, and we decided to evaluate the efficacy and safety of reduced doses of rivaroxaban after LAAC.

Methods:

ADRIFT (Assessment of Dual Antiplatelet Therapy Versus Rivaroxaban in Atrial Fibrillation Patients Treated With Left Atrial Appendage Closure) is a multicenter, phase IIb study, which randomized 105 patients after successful LAAC to either rivaroxaban 10 mg (R 10 , n=37), rivaroxaban 15 mg (R 15 , n=35), or DAPT with aspirin 75 mg and clopidogrel 75 mg (n=33). The primary end point was thrombin generation (prothrombin fragments 1+2) measured 2 to 4 hours after drug intake, 10 days after treatment initiation. Thrombin-antithrombin complex, D-dimers, rivaroxaban concentrations were also measured at 10 days and 3 months. Clinical end points were evaluated at 3-month follow-up.

Results:

The primary end point was reduced with R 10 (179 pmol/L [interquartile range (IQR), 129–273], P <0.0001) and R 15 (163 pmol/L [IQR, 112–231], P <0.0001) as compared with DAPT (322 pmol/L [IQR, 218–528]). We observed no significant reduction of the primary end point between R 10 and R 15 while rivaroxaban concentrations increased significantly from 184 ng/mL (IQR, 127–290) with R 10 to 274 ng/mL (IQR, 192–377) with R 15 , P <0.0001. Thrombin-antithrombin complex and D-dimers were numerically lower with both rivaroxaban doses than with DAPT. These findings were all confirmed at 3 months. The clinical end points were not different between groups. A device thrombosis was noted in 2 patients assigned to DAPT.

Conclusions:

Thrombin generation measured after LAAC was lower in patients treated by reduced rivaroxaban doses than DAPT, supporting an alternative to the antithrombotic regimens currently used after LAAC and deserves further evaluation in larger studies.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03273322.

Prothrombotic Responses After Catheter Ablation for Atrial Fibrillation During Uninterrupted Oral Anticoagulant Agent Administration

OBJECTIVES

The aim of this study was to evaluate the extent of changes in prothrombotic responses after catheter ablation for atrial fibrillation (AF) under uninterrupted oral anticoagulant agent (OAC) administration.

BACKGROUND

Catheter ablation for AF has a potential risk for prothrombotic activation and silent thromboembolic events.

METHODS

A total of 814 patients (n = 172 [warfarin], n = 153 [dabigatran], n = 134 [rivaroxaban], and n = 301 [apixaban] patients undergoing AF ablation and a control group of 54 patients undergoing non-AF ablation) were included. Uninterrupted OACs were administered during the procedure in patients with AF. Blood samples were collected the day before and 3 days after the procedure.

RESULTS

At baseline, D-dimer levels were within normal limits (≤1.0 μg/ml) in more than 90% of the patients in all groups. However, after 3 days, this proportion decreased to 67%, 73%, 59%, 68%, and 65% in the warfarin, dabigatran, rivaroxaban, apixaban, and control groups, respectively (p = 0.180). Changes in prothrombin fragment 1+2 levels differed (p < 0.001), whereas fibrin monomer complex levels 3 days after ablation at a trough were equivalent within normal ranges among the groups (p = 0.146). Multivariate analysis revealed that age, CHA₂DS₂-VASc score, first session, and radiofrequency ablation were independent predictors of increased D-dimer levels after the procedure. Various changes in prothrombotic markers were observed between the warfarin and direct OAC groups after propensity score matching analyses.

CONCLUSIONS

The coagulation cascade was activated after catheter ablation for AF under uninterrupted OAC administration. The changes in various prothrombotic markers differed among the OAC groups.

Effect of apixaban compared with warfarin on coagulation markers in atrial fibrillation

Objectives

Compare the effect of apixaban and warfarin on coagulation and primary haemostasis biomarkers in atrial fibrillation (AF).

Methods

The biomarker substudy from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial included 4850 patients with AF randomised to treatment with apixaban or warfarin. Sixty per cent of patients used vitamin K antagonist (VKA) within 7 days before randomisation. Prothrombin fragment 1+2 (F1+2), D-dimer, soluble CD40 ligand (sCD40L) and von Willebrand factor (vWF) antigen were analysed at randomisation and after 2 months of study treatment.

Results

In patients not on VKA treatment at randomisation, F1+2 and D-dimer levels were decreased by 25% and 23%, respectively, with apixaban, and by 59% and 38%, respectively, with warfarin (p<0.0001 for treatment differences for both). In patients on VKA at randomisation, F1+2 and D-dimer levels increased by 41% and 10%, respectively, with apixaban and decreased by 37% and 11%, respectively, with warfarin (p<0.0001 for treatment differences for both). sCD40L levels were slightly increased at 2 months, regardless of VKA or randomised treatment. Apixaban and warfarin also both reduced vWF antigen regardless of VKA treatment. The efficacy (stroke) and safety (bleeding) of apixaban compared with warfarin was similar irrespectively of biomarker levels at 2 months.

Conclusions

Treatment with apixaban compared with warfarin for stroke prevention in patients with AF was associated with less reduction in thrombin generation and fibrin turnover. This effect of apixaban could contribute to the clinical results where apixaban was superior to warfarin both in stroke prevention and in reducing bleeding risk.

Trial registration number

NCT00412984.

Thrombin Generation Biomarkers Decline With Parenteral Anticoagulation-An Overlooked Means of Anticoagulation Monitoring?

Anticoagulation therapy is administered to patients to prevent or stop thrombin generation in vivo. Although plasma tests of in vivo thrombin generation have been available for more than 2 decades, they are not routinely used in clinical trials or practice to monitor anticoagulation therapy. We observed a fall in one such marker, the D-dimer antigen, in patients receiving anticoagulation therapy. We therefore conducted a systematic review of the medical literature to document the change in serum biomarkers of thrombin generation following the initiation of anticoagulation therapy. Using a defined search strategy, we screened PubMed and Embase citations and identified full-length articles published in English. Eighteen articles containing serial changes in 1 of 3 markers of thrombin generation (D-dimer antigen, thrombin–antithrombin complexes, and prothrombin fragment 1+2 antigen levels) in the 14 days following the initiation of anticoagulation were identified. Even though the assays used varied considerably, each of the 3 markers of thrombin generation declined in the initial period of anticoagulation therapy, with changes evident as early as 1 day after beginning therapy. These observations provide a rationale for further exploration of these markers as measures of the adequacy of anticoagulation using classic as well as novel anticoagulants. Particular patient groups that would benefit from additional means of monitoring anticoagulation therapy are discussed.