Effects of Rivaroxaban on Biomarkers of Coagulation and Inflammation: A Post Hoc Analysis of the X-VeRT Trial

Disturbed atrial metabolism, shear stress, and cardiac load contribute to atrial fibrillation after ablation: AXAFA biomolecule study

AIMS

Different disease processes can combine to cause atrial fibrillation (AF). Their contribution to recurrent AF after ablation in patients is not known. Cardiovascular processes associated with recurrent AF after AF ablation were determined by quantifying biomolecules related to inflammation, metabolism, proliferation, fibrosis, shear stress, atrial pressure, and others in the AXAFA biomolecule study.

METHODS AND RESULTS

Twelve circulating cardiovascular biomolecules (ANGPT2, BMP10, CA125, hsCRP, ESM1, FABP3, FGF23, GDF15, IGFBP7, IL6, NT-proBNP, and hsTnT) were quantified in plasma samples obtained prior to a first AF ablation using high-throughput, high-precision assays. Cox regression was used to identify biomolecules associated with recurrent AF during the first 3 months after AF ablation. In 433 patients (64 years [58, 70]; 33% women), baseline concentrations of ANGPT2, BMP10, hsCRP, FGF23, FABP3, GDF15, and NT-proBNP were elevated in patients with recurrent AF (120/433; 28%). After adjustment for 11 clinical features and randomized treatment, elevated NT-proBNP [hazard ratio (HR) 1.58, 95% confidence interval (1.29, 1.94)], ANGPT2 [HR 1.37, (1.12, 1.67)], and BMP10 [HR 1.24 (1.02, 1.51)] remained associated with recurrent AF. Concentrations of ANGPT2, BMP10, and NT-proBNP decreased in patients who remained arrhythmia free, but not in patients with recurrent AF, highlighting their connection to AF. The other eight biomarkers showed unchanged concentrations.

CONCLUSION

Elevated concentrations of ANGPT2, BMP10, and NT-proBNP are associated with recurrent AF after a first AF ablation, suggesting that processes linked to disturbed cardiomyocyte metabolism, altered atrial shear stress, and increased load contribute to AF after AF ablation in patients.

Rivaroxaban Plasma Concentration and Clinical Outcomes on Older Patients with Non-valvular Atrial Fibrillation and Pulmonary Infection

INTRODUCTION

Infection may induce thrombotic and hemorrhagic events; however, it is currently unclear whether the inflammatory response affects the coagulation function and the clinical efficacy and safety of rivaroxaban in older patients with non-valvular atrial fibrillation (NVAF).

OBJECTIVE

This project aimed to assess the effectiveness and safety of the non-vitamin K antagonist oral anticoagulant rivaroxaban in older patients with NVAF complicated by infection, and to provide a basis for possible drug dose adjustment.

METHODS

A total of 152 NVAF patients aged ≥ 65 years admitted to the Fifth People's Hospital of Shanghai from June 2020 to May 2022 were included in this prospective, observational study. The changes in steady-state plasma concentration of rivaroxaban and FXa inhibition rate were compared between patients with and without infection, and the impact on the occurrence of infection, thrombotic events, and bleeding events was compared through 1-year follow-up.

RESULTS

Our results showed that patients in the infection group had abnormal inflammation markers, as well as an increased occurrence of bleeding and thrombotic events during hospitalization and follow-up. The high incidence of bleeding events in patients was closely related to the occurrence of infection, lymphocyte reduction, and increased neutrophil-lymphocyte ratio. The increase in thrombotic events was related to a decrease in rivaroxaban plasma concentration. Bleeding events in patients taking anticoagulant drugs are not necessarily due to drug accumulation.

CONCLUSIONS

Timely control of infection, assessment of bleeding and thrombotic risks, and selection of appropriate anticoagulation treatment strategies should be made in older NVAF patients who develop pulmonary infection.

CLINICAL TRIALS REGISTRATION

Chinese Clinical Trial Registry Number ChiCTR2000033144.

Anti-Inflammatory and Anticancer Effects of Anticoagulant Therapy in Patients with Malignancy

Optimizing the anticoagulation therapy is of pivotal importance in patients with a malignant tumor, as venous thromboembolism (VTE) has become the second-leading cause of death in this population. Cancer can highly increase the risk of thrombosis and bleeding. Consequently, the management of cancer-associated VTE is complex. In recent years, translational research has intensified, and several studies have highlighted the role of inflammatory cytokines in cancer growth and progression. Simultaneously, the pleiotropic effects of anticoagulants currently recommended for VTE have emerged. In this review, we describe the anti-inflammatory and anticancer effects of both direct oral anticoagulants (DOACs) and low-molecular-weight heparins (LWMHs).

Inflammasome Signaling, Thromboinflammation, and Venous Thromboembolism

Venous thromboembolism (VTE) remains a major health burden despite anticoagulation advances, suggesting incomplete management of pathogenic mechanisms. The NLRP3 (NACHT-, LRR- and pyrin domain-containing protein 3) inflammasome, interleukin (IL)-1, and pyroptosis are emerging contributors to the inflammatory pathogenesis of VTE. Inflammasome pathway activation occurs in patients with VTE. In preclinical models, inflammasome signaling blockade reduces venous thrombogenesis and vascular injury, suggesting that this therapeutic approach may potentially maximize anticoagulation benefits, protecting from VTE occurrence, recurrence, and ensuing post-thrombotic syndrome. The nonselective NLRP3 inhibitor colchicine and the anti-IL-1β agent canakinumab reduce atherothrombosis without increasing bleeding. Rosuvastatin reduces primary venous thrombotic events at least in part through lipid-lowering independent mechanisms, paving the way to targeted anti-inflammatory strategies in VTE. This review outlines recent preclinical and clinical evidence supporting a role for inflammasome pathway activation in venous thrombosis, and discusses the, yet unexplored, therapeutic potential of modulating inflammasome signaling to prevent and manage VTE.

The role of coagulome in the tumor immune microenvironment

The rising incidence and persistent thrombosis in multiple cancers including those that are immunosuppressive highlight the need for understanding the tumor coagulome system and its role beyond hemostatic complications. Immunotherapy has shown significant benefits in solid organ tumors but has been disappointing in the treatment of hypercoagulable cancers, such as glioblastoma and pancreatic ductal adenocarcinomas. Thus, targeting thrombosis to prevent immunosuppression seems a clinically viable approach in cancer treatment. Hypercoagulable tumors often develop fibrin clots within the tumor microenvironment (TME) that dictates the biophysical characteristics of the tumor tissue. The application of systems biology and single-cell approaches highlight the potential role of coagulome or thrombocytosis in shaping the tumor immune microenvironment (TIME). In-depth knowledge of the tumor coagulome would provide unprecedented opportunities to better predict the hemostatic complications, explore how thrombotic stroma modulates tumor immunity, reexamine the significance of clinical biomarkers, and enable steering the stromal versus systemic immune response for boosting the effectiveness of immune checkpoint inhibitors in cancer treatment. We focus on the role of coagulation factors in priming a suppressive TIME and the huge potential of existing anticoagulant drugs in the clinical settings of cancer immunotherapy.

Rivaroxaban attenuates neutrophil maturation in the bone marrow niche

Pharmacological inhibition of factor Xa by rivaroxaban has been shown to mediate cardioprotection and is frequently used in patients with, e.g., atrial fibrillation. Rivaroxaban's anti-inflammatory actions are well known, but the underlying mechanisms are still incompletely understood. To date, no study has focused on the effects of rivaroxaban on the bone marrow (BM), despite growing evidence that the BM and its activation are of major importance in the development/progression of cardiovascular disease. Thus, we examined the impact of rivaroxaban on BM composition under homeostatic conditions and in response to a major cardiovascular event. Rivaroxaban treatment of mice for 7 days markedly diminished mature leukocytes in the BM. While apoptosis of BM-derived mature myeloid leukocytes was unaffected, lineage-negative BM cells exhibited a differentiation arrest at the level of granulocyte-monocyte progenitors, specifically affecting neutrophil maturation via downregulation of the transcription factors Spi1 and Csfr1. To assess whether this persists also in situations of increased leukocyte demand, mice were subjected to cardiac ischemia/reperfusion injury (I/R): 7 d pretreatment with rivaroxaban led to reduced cardiac inflammation 72 h after I/R and lowered circulating leukocyte numbers. However, BM myelopoiesis showed a rescue of the leukocyte differentiation arrest, indicating that rivaroxaban's inhibitory effects are restricted to homeostatic conditions and are mainly abolished during emergency hematopoiesis. In translation, ST-elevation MI patients treated with rivaroxaban also exhibited reduced circulating leukocyte numbers. In conclusion, we demonstrate that rivaroxaban attenuates neutrophil maturation in the BM, which may offer a therapeutic option to limit overshooting of the immune response after I/R.

Rivaroxaban in patients with abdominal aortic aneurysm and high-sensitivity C-reactive protein elevation (BANBOO): study protocol for a randomized, controlled trial

BACKGROUND

Abdominal aortic aneurysm (AAA) is a fatal disease due to the tendency to rupture. The drug treatment for small AAA without surgical indications has been controversial. Previous studies showed that high-sensitivity C-reactive protein (hs-CRP) had become a potential biomarker of the disease, and the anti-inflammatory effect of rivaroxaban for AAA had been well established. Thus, we hypothesized that rivaroxaban could control the progression of AAA in patients with hs-CRP elevation.

METHODS

The study is a prospective, open-label, randomized, controlled clinical trial. Sixty subjects are recruited from the General Hospital of Northern Theatre Command of China. Subjects are randomly assigned (1:1) to the intervention arm (rivaroxaban) or control arm (aspirin). The primary efficacy outcome is the level of serum hs-CRP at 6 months. The secondary outcomes include imaging examination (the maximal diameter of AAA, the maximal thickness of mural thrombus, and the length of aneurysm), major adverse cardiovascular and cerebrovascular events (MACCE, including AAA transformation, non-fatal myocardial infarction, acute congestive heart failure, stent thrombosis, ischemia-driven target vessel revascularization, vascular amputation, stroke, cardiovascular death, and all-cause death), and other laboratory tests (troponin T, interleukin 6, D-dimer, and coagulation function).

DISCUSSION

The BANBOO trial tested the effect of rivaroxaban on the progression of AAA in patients with elevated Hs-CRP for the first time.

TRIAL REGISTRATION

ChiCTR2100051990, ClinicalTrials.gov, registered on 12 October 2021.

Combined Use of Tranexamic Acid and Rivaroxaban in Posterior/Transforaminal Lumbar Interbody Fusion Surgeries Safely Reduces Blood Loss and Incidence of Thrombosis: Evidence From a Prospective, Randomized, Double-Blind, Placebo-Controlled Study

STUDY DESIGN

A prospective, randomized, double-blind, placebo-controlled study.

OBJECTIVES

There are few studies examining the balance between preventing venous thrombus embolism (VTE) and reducing blood loss in posterior/transforaminal lumbar interbody fusion (PLIF/TLIF) surgeries. This study aimed to evaluate the efficacy and safety of the combine application of TXA and rivaroxaban in patients undergoing PLIF/TLIF and explore relevant factors related to blood loss and VTE.

METHODS

Patients in group A which was the control group received 0.9% NaCl solution intravenously. Group B was treated by an intravenous injection of 2 g tranexamic acid (TXA) and the local use of 1 g intraoperatively. Group C was treated the same as group B intraoperatively, and they received 10 mg rivaroxaban qd treatment postoperatively. Eligible patients with an Autar score ≤ 10 were randomly assigned to group A or group B. Patients with an Autar score >10 were allocated into group C.

RESULTS

The intraoperative blood loss and postoperative drainage were lower in groups B and C than in group A (P < .001). The blood transfusion rate in group B was lower than that in group A (P < .001), while the incidence of VTE in group C was lower (P < .001). Four factors were found to be positively correlated with obvious total blood loss (P < .05). The data showed that 5 factors were correlated with the development of a thrombus (P < .1).

CONCLUSIONS

The combination of TXA and rivaroxaban in PLIF/TLIF patients is safe and effective in reducing D-dimer levels associated with VTE and reducing blood loss.

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.

Dual Pathway Inhibition with Rivaroxaban and Aspirin Reduces Inflammatory Biomarkers in Atherosclerosis

ABSTRACT

Dual pathway inhibition (DPI) with low-dose rivaroxaban and aspirin in patients with coronary artery disease (CAD) and/or peripheral artery disease (PAD) reduces the occurrence of cardiovascular (CV) events; however, the underlying mechanisms explaining these latter CV benefits are not clearly understood. Our explorative observational study aimed to evaluate the effect of dual pathway inhibition on plasma inflammation and coagulation markers among real-world patients with CAD and/or PAD. We prospectively included all consecutive patients with an established diagnosis of CAD and/or PAD treated with aspirin 100 mg once daily (OD) and rivaroxaban 2.5 mg twice daily (TD). Clinical evaluation and laboratory analyses, including hemoglobin, renal function (creatinine, urea, and cystatin-C), coagulation markers (INR and aPTT), inflammation markers (IL-6, CRP, lipoprotein-associated phospholipase A2, and copeptin), and growth differentiation factor-15 (GDF-15), were conducted at baseline, before starting treatment, and at 4 and 24 weeks after study drug administration. Fifty-four consecutive patients (mean age 66 ± 7 years; male 83%) who completed the 6-month follow-up were included. At 24-week follow-up, a statistically significant reduction in IL-6 serum levels [4.6 (3.5-6.5) vs. 3.4 (2.4-4.3) pg/mL ; P = 0.0001] and fibrinogen [336 (290-390) vs. 310 (275-364) mg/dL; P = 0.04] was shown; moreover, a significant increase in GDF-15 serum level [1309 (974-1961) vs. 1538 (1286-2913) pg/mL; P = 0.002] was observed. Hemoglobin, renal function, and cardiovascular homeostasis biomarkers remain stable over the time. The anti-Xa activity at both [0.005 (0-0.02) vs. 0.2 (0.1-0.34); P < 0.0001) significantly increased. The dual pathway inhibitions with low-dose rivaroxaban and aspirin in patients with CAD and/or PAD were associated with the reduction of inflammation biomarkers.

Pathophysiological mechanisms of thrombosis in acute and long COVID-19

COVID-19 patients have a high incidence of thrombosis, and thromboembolic complications are associated with severe COVID-19 and high mortality. COVID-19 disease is associated with a hyper-inflammatory response (cytokine storm) mediated by the immune system. However, the role of the inflammatory response in thrombosis remains incompletely understood. In this review, we investigate the crosstalk between inflammation and thrombosis in the context of COVID-19, focusing on the contributions of inflammation to the pathogenesis of thrombosis, and propose combined use of anti-inflammatory and anticoagulant therapeutics. Under inflammatory conditions, the interactions between neutrophils and platelets, platelet activation, monocyte tissue factor expression, microparticle release, and phosphatidylserine (PS) externalization as well as complement activation are collectively involved in immune-thrombosis. Inflammation results in the activation and apoptosis of blood cells, leading to microparticle release and PS externalization on blood cells and microparticles, which significantly enhances the catalytic efficiency of the tenase and prothrombinase complexes, and promotes thrombin-mediated fibrin generation and local blood clot formation. Given the risk of thrombosis in the COVID-19, the importance of antithrombotic therapies has been generally recognized, but certain deficiencies and treatment gaps in remain. Antiplatelet drugs are not in combination with anticoagulant treatments, thus fail to dampen platelet procoagulant activity. Current treatments also do not propose an optimal time for anticoagulation. The efficacy of anticoagulant treatments depends on the time of therapy initiation. The best time for antithrombotic therapy is as early as possible after diagnosis, ideally in the early stage of the disease. We also elaborate on the possible mechanisms of long COVID thromboembolic complications, including persistent inflammation, endothelial injury and dysfunction, and coagulation abnormalities. The above-mentioned contents provide therapeutic strategies for COVID-19 patients and further improve patient outcomes.

Preadmission Oral Anticoagulation for Atrial Fibrillation/Flutter and Death or Thrombotic Events During COVID-19 Admission

Atrial fibrillation/flutter (AF) and COVID-19 are associated with an elevated risk of arterial and venous thrombosis. Whether preadmission oral anticoagulation (OAC) for AF reduces the incidence of in-hospital death or thrombotic events among patients with COVID-19 is unknown. We identified 630 patients with pre-existing AF and a hospitalization diagnosis of COVID-19 and stratified them according to preadmission OAC use. Multivariable logistic regression was employed to relate preadmission OAC to composite in-hospital mortality or thrombotic events. Unadjusted composite in-hospital mortality or thrombotic complications occurred less often in those on than not on preadmission OAC (27.1% vs 46.8%, p <0.001). After adjustment, the incidence of composite in-hospital all-cause mortality or thrombotic complications remained lower with preadmission OAC (odds ratio 0.37, confidence interval 0.25 to 0.53, p <0.0001). Secondary outcomes including all-cause mortality (16.3% vs 24.9%, p = 0.007), intensive care unit admission (14.7% vs 29.0%, p <0.001), intubation (6.4% vs 18.6%, p <0.001), and noninvasive ventilation (18.6% vs 27.5%, p = 0.007) occurred less frequently, and length of stay was shorter (6 vs 7 days, p <0.001) in patients on than those not on preadmission OAC. A higher CHA₂DS₂-VASc score was associated with an increased risk of thrombotic events. In conclusion, among patients with baseline AF who were hospitalized with COVID-19, those on preadmission OAC had lower rates of death, arterial and venous thrombotic events, and less severe COVID-19.

Put out the fire: The pleiotropic anti-inflammatory action of non-vitamin K oral anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs) should be the preferred anticoagulant strategy for preventing ischemic stroke in patients with atrial fibrillation (AF) at increased thromboembolic risk and for treating deep venous thromboembolism (DVT) in the general population. Beyond their inhibiting action on the activated factor X (FXa) or thrombin (FIIa), NOACs showed some pleiotropic anti-inflammatory effects. The present review aimed to describe the role of FXa and FIIa in the inflammation pathway and the potential anti-inflammatory effects of NOACs.

DOACs and Atherosclerotic Cardiovascular Disease Management: Can We Find the Right Balance Between Efficacy and Harm

PURPOSE OF REVIEW

The balance between efficacy and harm remains a challenge in the adoption of non-vitamin K antagonist direct oral anticoagulants (DOACs) for secondary atherosclerotic disease prevention. We provide a comprehensive review of the evidence for and against the addition of DOACs to the current management of atherosclerotic cardiovascular disease, including stable coronary artery disease (CAD), acute coronary syndrome (ACS), peripheral artery disease (PAD), and percutaneous coronary interventions (PCI).

RECENT FINDINGS

The DOAC class exerts pleiotropic effects on atherosclerotic progression through coagulation and inflammatory pathways. In ACS, low-dose DOAC provides no added efficacy in the setting of dual antiplatelet therapy; however, full-dose DOAC increases bleeding. Efficacy-safety profile favor use of low-dose rivaroxaban in select stable CAD or PAD patients. Atrial fibrillation patients undergoing PCI resort to dual therapy with DOAC due to prohibitory bleeding with triple anti-thrombotic therapy. Evidence favors DOAC use in CAD and PAD; however, careful individual considerations must be undertaken.

Increased Prevalence of Elevated D-Dimer Levels in Patients on Direct Oral Anticoagulants: Results of a Large Retrospective Study

Elevated D-dimer levels during anticoagulant therapy with vitamin K antagonists (VKA) are associated with an increased risk of thrombosis. It has been hypothesized that elevated D-dimer levels in patients receiving direct oral anticoagulants (DOACs) also indicate an increased risk of thrombosis recurrence, but data on the distribution of D-dimer levels in patients with VTE on DOACs are sparse. In the present study we retrospectively analyzed D-dimer levels in patients taking DOACs after first or recurrent venous thrombosis (n = 1,716, 1,126 thereof rivaroxaban, 481 apixaban, 62 edoxaban, and 47 dabigatran). Patients on VKA (n = 402) served as control group. Thrombotic events in the study population were categorized into distal deep venous thrombosis (DVT, n = 552 patients), distal DVT with pulmonary embolism (PE, n = 166), proximal DVT (n = 685), proximal DVT with PE (n = 462), PE without DVT (n = 522), DVT of the upper extremity (n = 78), cerebral venous sinus thrombosis (CVST, n = 48), and other venous thrombosis (n = 74). In VKA users a median D-dimer level of 0.20 mg/l was observed. In patients on DOACs D-dimer levels were significantly higher, with 0.26 mg/l for rivaroxaban, 0.31 mg/l for apixaban (P &lt; 10−16 each), 0.24 mg/l for edoxaban (P = 2 × 10−5), and 0.25 mg/l for dabigatran (P = 4 × 10−4). These differences in comparison to patients on VKA treatment could not be explained by the patients' age, sex, body mass index, and type of thrombosis as these characteristics did not differ significantly between cohorts. Moreover, the prevalence of D-dimer levels above age-adjusted cut-offs [≥0.50 mg/l in ≤50-year-old patients, ≥(age × 0.01) mg/l in &gt;50-year-old patients] was higher in patients on rivaroxaban (13.9%, RR 1.74, 95% CI 1.21–2.50), apixaban (17.0%, RR 2.14, 95% CI 1.45–3.15) and dabigatran (23.4%, RR 2.94, 95% CI 1.59–5.44) than in patients on VKA (8.0%). In patients on edoxaban D-dimer levels above the reference range were observed in 14.5%, but no statistical significance was reached in comparison to the VKA cohort. In conclusion, the obtained data suggest, that the type of oral anticoagulant should be considered in the clinical assessment of D-dimer levels in thrombosis patients. Further studies are warranted to evaluate a potential association between elevated D-dimer levels and thrombosis risk in patients on DOACs.

Rivaroxaban compared with low-dose aspirin in individuals with type 2 diabetes and high cardiovascular risk: a randomised trial to assess effects on endothelial function, platelet activation and vascular biomarkers

AIMS/HYPOTHESIS

Individuals with type 2 diabetes mellitus and subclinical inflammation have stimulated coagulation, activated platelets and endothelial dysfunction. Recent studies with the direct factor Xa inhibitor rivaroxaban in combination with low-dose aspirin demonstrated a significant reduction of major cardiovascular events, especially in individuals with type 2 diabetes and proven cardiovascular disease. Therefore, we asked the question of whether treatment with rivaroxaban could influence endothelial function, arterial stiffness and platelet activation.

METHODS

We conducted a multi-centre, prospective, randomised, open-label trial in 179 participants with type 2 diabetes (duration 2-20 years), subclinical inflammation (high-sensitivity C-reactive protein 2-10 mg/l) and at least two traits of the metabolic syndrome to compare the effects of the direct factor Xa inhibitor rivaroxaban (5 mg twice daily) vs aspirin (100 mg every day) on endothelial function (assessed by forearm occlusion plethysmography), skin blood flow (assessed by laser-Doppler fluxmetry), arterial stiffness (assessed by pulse wave velocity) and serum biomarkers of endothelial function and inflammation. Furthermore, we investigated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in platelets, the concentration of platelet-derived microparticles (PMPs) and the effects of isolated PMPs on HUVEC proliferation in vitro.

RESULTS

Rivaroxaban treatment for 20 weeks (n = 89) resulted in a significant improvement of post-ischaemic forearm blood flow (3.6 ± 4.7 vs 1.0 ± 5.2 ml/100 ml, p = 0.004), a numerically increased skin blood flow and reduced soluble P-Selectin plasma level vs aspirin. We did not find significant differences of arterial stiffness or further biomarkers. Neither rivaroxaban nor aspirin influenced VASP phosphorylation of platelets. The number of PMPs increased significantly with both rivaroxaban (365.2 ± 372.1 vs 237.4 ± 157.1 μl^-1, p = 0.005) and aspirin (266.0 ± 212.7 vs 201.7 ± 162.7 μl^-1, p = 0.021). PMPs of rivaroxaban-treated participants stimulated HUVEC proliferation in vitro compared with aspirin. Rivaroxaban was associated with a higher number of bleeding events.

CONCLUSIONS/INTERPRETATION

Our findings indicate that the direct factor Xa inhibitor rivaroxaban improved endothelial function in participants with type 2 diabetes and subclinical inflammation but also increased the risk of bleeding.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02164578.

FUNDING

The study was supported by a research grant from Bayer Vital AG, Germany.

Vascular Protective Effects of New Oral Anticoagulants in Patients with Atrial Fibrillation

This study was designed to determine the efficacy of a new oral anticoagulant (NOAC) therapy for the prevention of endothelial dysfunction and atherosclerosis progression in patients with atrial fibrillation (AF). Sixty-five AF patients with a CHA2DS2-VASc score ≥2 without previous history of cardiovascular disease were registered and randomly assigned to either an NOAC group (dabigatran or rivaroxaban) or the warfarin group. Reactive hyperemia peripheral arterial tonometry (RH-PAT) measurements reflecting endothelial function were taken using Endo-PAT2000. Carotid intima–media thickness (IMT) was measured at baseline, 12 months, and 24 months, and several biomarkers were also analyzed. For the primary end point, the reactive hyperemia index (RHI) for the NOAC group was 1.5 ± 0.4 and that for the warfarin group was 1.6 ± 0.5. The left and right carotid IMT was 0.7 mm in the NOAC groups and 0.8 mm in the warfarin group. At 12 months, RHI was 1.6 ± 0.3 for the dabigatran group, 1.6 ± 0.5 for the rivaroxaban group, and 1.6 ± 0.3 for the warfarin group. The three groups did not differ statistically with respect to change in left and right carotid IMT at 12 and 24 months, respectively. The biomarkers for endothelial function and atherosclerosis were not significantly different. There was a trend of reduced P-selectin levels in the NOAC group compared to the warfarin group. In patients with AF, there were no significant differences in the prevention of endothelial dysfunction and atherosclerosis progression between the NOAC and warfarin groups.

Characteristics of atherosclerosis in femoropopliteal artery and its clinical relevance

Atherosclerosis is a systemic disease with different faces. Despite identical or similar pathogenetic mechanisms, atherosclerotic lesions and their clinical manifestations vary in different parts of the vascular system. Peripheral arterial disease (PAD) represents one of the most frequent clinical manifestations of atherosclerosis with predominant location in the superficial femoral artery (SFA). Morphological characteristics of atherosclerotic plaques in peripheral arteries differ from lesions in the coronary and carotid arteries. Plaques in SFA have more fibrotic components, less lipids and inflammatory cells, which makes them more stable and less prone to rupture. Factors that determine the different structure of plaques in SFA compared to coronary arteries include hemodynamic forces, vasa vasorum and calcification. Low shear stress in SFA in the adductor canal is one of the factors which determines frequent atherosclerotic lesions in this region. Lower lipid content and fewer inflammatory cells explain higher stability of SFA plaques. The specific structure of SFA plaques may require preventive and therapeutic measures, which to some extent differ from prevention of coronary atherosclerosis and may include inhibition of fibrotic proliferation in SFA plaques and calcification. Revascularization of PAD differs from procedures used in coronary arteries and requires specific technical expertise and devices.

Impact of Transcatheter Aortic Valve Implantation on Thrombin Generation and Platelet Function

BACKGROUND

 Transcatheter aortic valve implantation (TAVI) is an evolving treatment of severe aortic valve stenosis. However, thromboembolic events such as stroke are common, predominantly early after TAVI. Optimal periprocedural antithrombotic regime is unknown. Especially, as antithrombotic medication enhances bleeding risk, thrombin generation and platelet function are crucial in the pathogenesis of ischemic events. However, the impact of the TAVI procedure on thrombin formation and platelet reactivity is not known by now.

METHODS

 We evaluated thrombin levels using thrombin-antithrombin (TAT) complexes and prothrombin fragments (PTFs) using enzyme-linked immunosorbent assay. Furthermore, platelet reactivity was measured via light transmission aggregometry before and 2 hours after TAVI in 198 patients.

RESULTS

 TAT complexes and PTF F1 + 2 substantially increased during TAVI. Postprocedurally, TAT complexes and PTF were significantly higher after TAVI compared with percutaneous coronary intervention due to acute myocardial infarction, while preprocedural TAT complexes and PTF F1 + 2 did not differ. In contrast, platelet reactivity was not altered early after TAVI. Only adenosine diphosphate-induced aggregation was reduced, reflecting preprocedural loading with clopidogrel.

CONCLUSION

 In this pilot study, we were able to demonstrate that thrombin generation is significantly increased early after TAVI, while platelet function is not affected. Increased thrombin concentrations may contribute to the high risk of postprocedural thromboembolic events. This leads to the hypothesis that extended peri-interventional anticoagulation early after TAVI may be an approach to reduce thromboembolic events.

Interplay between inflammation and thrombosis in cardiovascular pathology

Thrombosis is the most feared complication of cardiovascular diseases and a main cause of death worldwide, making it a major health-care challenge. Platelets and the coagulation cascade are effectively targeted by antithrombotic approaches, which carry an inherent risk of bleeding. Moreover, antithrombotics cannot completely prevent thrombotic events, implicating a therapeutic gap due to a third, not yet adequately addressed mechanism, namely inflammation. In this Review, we discuss how the synergy between inflammation and thrombosis drives thrombotic diseases. We focus on the huge potential of anti-inflammatory strategies to target cardiovascular pathologies. Findings in the past decade have uncovered a sophisticated connection between innate immunity, platelet activation and coagulation, termed immunothrombosis. Immunothrombosis is an important host defence mechanism to limit systemic spreading of pathogens through the bloodstream. However, the aberrant activation of immunothrombosis in cardiovascular diseases causes myocardial infarction, stroke and venous thromboembolism. The clinical relevance of aberrant immunothrombosis, referred to as thromboinflammation, is supported by the increased risk of cardiovascular events in patients with inflammatory diseases but also during infections, including in COVID-19. Clinical trials in the past 4 years have confirmed the anti-ischaemic effects of anti-inflammatory strategies, backing the concept of a prothrombotic function of inflammation. Targeting inflammation to prevent thrombosis leaves haemostasis mainly unaffected, circumventing the risk of bleeding associated with current approaches. Considering the growing number of anti-inflammatory therapies, it is crucial to appreciate their potential in covering therapeutic gaps in cardiovascular diseases.

Potential Therapeutic Roles for Direct Factor Xa Inhibitors in Coronavirus Infections

Human factor Xa (FXa) is a serine protease of the common coagulation pathway. FXa is known to activate prothrombin to thrombin, which eventually leads to the formation of cross-linked blood clots. While this process is important in maintaining hemostasis, excessive thrombin generation results in a host of thrombotic conditions. FXa has also been linked to inflammation via protease-activated receptors. Together, coagulopathy and inflammation have been implicated in the pathogenesis of viral infections, including the current coronavirus pandemic. Direct FXa inhibitors have been shown to possess anti-inflammatory and antiviral effects, in addition to their established anticoagulant activity. This review summarizes the pharmacological activities of direct FXa inhibitors, their pharmacokinetics, potential drug–drug interactions and adverse effects, and the details of clinical trials involving direct FXa inhibitors in coronavirus disease 2019 (COVID-19) patients.

Comparison of Inflammatory Mediators in Patients With Atrial Fibrillation Using Warfarin or Rivaroxaban

Background: Atrial fibrillation (AF) is the most common arrhythmia associated with high risk of venous thromboembolism. Inflammatory mechanisms may be involved in the pathophysiology of AF and in the AF-related thrombogenesis, and patients with AF might benefit from the use of anticoagulants with anti-inflammatory properties. However, the evidence is still scarce, and it points out the need of trials seeking to investigate the levels of inflammatory mediators in patients with AF under different anticoagulant therapies. Therefore, this study was designed to define whether patients with AF treated either with an activated coagulation factor X (FXa) inhibitor (rivaroxaban) or with a vitamin K inhibitor (warfarin) present changes in peripheral levels of inflammatory mediators, mainly cytokines and chemokines. Methods: A total of 127 subjects were included in this study, divided into three groups: patients with non-valvular atrial fibrillation (NVAF) using warfarin (N = 42), patients with NVAF using rivaroxaban (N = 29), and controls (N = 56). Plasma levels of inflammatory mediators were quantified by immunoassays. Results: Patients with AF (both warfarin and rivaroxaban groups) presented increased levels of inflammatory cytokines in comparison with controls. The use of rivaroxaban was associated with decreased levels of inflammatory cytokines in comparison with warfarin. On the other hand, patients with AF using rivaroxaban presented increased levels of the chemokines (MCP-1 in comparison with warfarin users; MIG and IP-10 in comparison with controls). Conclusions: AF is associated with an inflammatory profile that was less pronounced in patients on rivaroxaban in comparison with warfarin users. Further studies are necessary to assess the clinical implications of our results and whether patients with AF would benefit from rivaroxaban anti-inflammatory effects.