Aspirin plus warfarin compared to aspirin alone after acute coronary syndromes: an updated and comprehensive meta-analysis of 25,307 patients

Thrombin as target for prevention of recurrent events after acute coronary syndromes

The mechanism underlying thrombus formation in acute coronary syndrome (ACS) involves both platelets and thrombin. While both pathways are targeted in acute care, platelet inhibition has been predominantly administered in the chronic phase, yet thrombin plays a key role in platelet activation and fibrin formation. Among ACS patients, there is also a persistent chronic increase in thrombin generation, which is associated with a higher rate of adverse events. In the setting of post-ACS care with rivaroxaban or vorapaxar, targeting thrombin has been associated with decreased thrombin generation and reduced cardiovascular events, but has been associated with increased bleeding risk. We explored the evidence supporting thrombin generation in the pathophysiology of recurrent events post-ACS and the role of thrombin as a viable therapeutic target. One specific target is factor XI inhibition, which is involved in thrombin generation, but may also allow for the preservation of normal hemostasis.

Non-vitamin-K-antagonist oral anticoagulants (NOACs) after acute myocardial infarction: a network meta-analysis

BACKGROUND

Balancing the risk of bleeding and thrombosis after acute myocardial infarction (AMI) is challenging, and the optimal antithrombotic therapy remains uncertain. The potential of non-vitamin K antagonist oral anticoagulants (NOACs) to prevent ischaemic cardiovascular events is promising, but the evidence remains limited.

OBJECTIVES

To evaluate the efficacy and safety of non-vitamin-K-antagonist oral anticoagulants (NOACs) in addition to background antiplatelet therapy, compared with placebo, antiplatelet therapy, or both, after acute myocardial infarction (AMI) in people without an indication for anticoagulation (i.e. atrial fibrillation or venous thromboembolism).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, the Conference Proceedings Citation Index - Science, and two clinical trial registers in September 2022 with no language restrictions. We checked the reference lists of included studies for any additional trials.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) that evaluated NOACs plus antiplatelet therapy versus placebo, antiplatelet therapy, or both, in people without an indication for anticoagulation after an AMI.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked the results of searches to identify relevant studies, assessed each included study, and extracted study data. We conducted random-effects pairwise analyses using Review Manager Web, and network meta-analysis using the R package 'netmeta'. We ranked competing treatments by P scores, which are derived from the P values of all pairwise comparisons and allow ranking of treatments on a continuous 0-to-1 scale.

MAIN RESULTS

We identified seven eligible RCTs, including an ongoing trial that we could not include in the analysis. Of the six RCTs involving 33,039 participants, three RCTs compared rivaroxaban with placebo, two RCTs compared apixaban with placebo, and one RCT compared dabigatran with placebo. All participants in the six RCTs received concomitant antiplatelet therapy. The available evidence suggests that rivaroxaban compared with placebo reduces the rate of all-cause mortality (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.69 to 0.98; number needed to treat for an additional beneficial outcome (NNTB) 250; 3 studies, 21,870 participants; high certainty) and probably reduces cardiovascular mortality (RR 0.83, 95% CI 0.69 to 1.01; NNTB 250; 3 studies, 21,870 participants; moderate certainty). There is probably little or no difference between apixaban and placebo in all-cause mortality (RR 1.09, 95% CI 0.88 to 1.35; number needed to treat for an additional harmful outcome (NNTH) 334; 2 studies, 8638 participants; moderate certainty) and cardiovascular mortality (RR 0.99, 95% CI 0.77 to 1.27; number needed to treat not applicable; 2 studies, 8638 participants; moderate certainty). Dabigatran may reduce the rate of all-cause mortality compared with placebo (RR 0.57, 95% CI 0.31 to 1.06; NNTB 63; 1 study, 1861 participants; low certainty). Dabigatran compared with placebo may have little or no effect on cardiovascular mortality, although the point estimate suggests benefit (RR 0.72, 95% CI 0.34 to 1.52; NNTB 143; 1 study, 1861 participants; low certainty). Two of the investigated NOACs were associated with an increased risk of major bleeding compared to placebo: apixaban (RR 2.41, 95% CI 1.44 to 4.06; NNTH 143; 2 studies, 8544 participants; high certainty) and rivaroxaban (RR 3.31, 95% CI 1.12 to 9.77; NNTH 125; 3 studies, 21,870 participants; high certainty). There may be little or no difference between dabigatran and placebo in the risk of major bleeding (RR 1.74, 95% CI 0.22 to 14.12; NNTH 500; 1 study, 1861 participants; low certainty). The results of the network meta-analysis were inconclusive between the different NOACs at all individual doses for all primary outcomes. However, low-certainty evidence suggests that apixaban (combined dose) may be less effective than rivaroxaban and dabigatran for preventing all-cause mortality after AMI in people without an indication for anticoagulation.

AUTHORS' CONCLUSIONS

Compared with placebo, rivaroxaban reduces all-cause mortality and probably reduces cardiovascular mortality after AMI in people without an indication for anticoagulation. Dabigatran may reduce the rate of all-cause mortality and may have little or no effect on cardiovascular mortality. There is probably no meaningful difference in the rate of all-cause mortality and cardiovascular mortality between apixaban and placebo. Moreover, we found no meaningful benefit in efficacy outcomes for specific therapy doses of any investigated NOACs following AMI in people without an indication for anticoagulation. Evidence from the included studies suggests that rivaroxaban and apixaban increase the risk of major bleeding compared with placebo. There may be little or no difference between dabigatran and placebo in the risk of major bleeding. Network meta-analysis did not show any superiority of one NOAC over another for our prespecified primary outcomes. Although the evidence suggests that NOACs reduce mortality, the effect size or impact is small; moreover, NOACs may increase major bleeding. Head-to-head trials, comparing NOACs against each other, are required to provide more solid evidence.

Pharmacodynamic Drug-Drug Interactions and Bleeding Outcomes in Patients with Atrial Fibrillation Using Non-Vitamin K Antagonist Oral Anticoagulants: a Nationwide Cohort Study

PURPOSE

Pharmacodynamic drug-drug interactions (PD DDIs) may influence the safety of non-vitamin K antagonist oral anticoagulants (NOACs), but the extent to which PD DDIs increase bleeding risks, remains unclear. Therefore, the impact of PD DDIs on bleeding outcomes in NOAC-treated patients with atrial fibrillation (AF) was investigated.

METHODS

Using Belgian nationwide data, NOAC-treated AF patients were included between 2013-2019. Concomitant use of PD interacting drugs when initiating NOAC treatment was identified.

RESULTS

Among 193,072 patients, PD DDIs were identified in 114,122 (59.1%) subjects. After multivariable adjustment, concomitant use of PD interacting drugs was associated with significantly higher risks of major or clinically-relevant non-major bleeding (adjusted hazard ratio (aHR) 1.19, 95% confidence interval (CI) (1.13-1.24)), gastrointestinal (aHR 1.12, 95%CI (1.03-1.22)), urogenital (aHR 1.21, 95%CI (1.09-1.35)) and other bleeding (aHR 1.28, 95%CI (1.20-1.36)), compared to NOAC-treated AF patients without PD interacting drug use. Increased bleeding risks were most pronounced with P2Y12 inhibitors (aHR 1.62, 95%CI (1.48-1.77)) and corticosteroids (aHR 1.53, 95%CI (1.42-1.66)), followed by selective serotonin or serotonin and norepinephrine reuptake inhibitors (SSRI/SNRI, aHR 1.26, 95%CI (1.17-1.35)), low-dose aspirin (aHR 1.14, 95%CI (1.08-1.20)) and non-steroidal anti-inflammatory drugs (NSAID, aHR 1.10, 95%CI (1.01-1.21)). Significantly higher intracranial bleeding risks in NOAC users were observed with SSRI/SNRIs (aHR 1.50, 95%CI (1.25-1.81)) and corticosteroids (aHR 1.49, 95%CI (1.21-1.84)).

CONCLUSION

Concomitant use of PD interacting drugs, especially P2Y12 inhibitors and corticosteroids, was associated with higher major, gastrointestinal, urogenital, and other bleeding risks in NOAC-treated AF patients. Remarkably, higher intracranial bleeding risks were observed with SSRI/SNRIs and corticosteroids.

Role of cerebral microbleeds in acute ischemic stroke and atrial fibrillation

Cerebral microbleeds (CMBs) are commonly detected in the brains of patients with acute ischemic stroke (AIS). With the development of neuroimaging, clinicians are paying more attention to the presence of CMBs. CMBs were found to significantly increase the risk of intracranial hemorrhagic transformation and hemorrhage in patients with AIS, especially in patients with concurrent atrial fibrillation (AF). Additionally, the presence of CMBs is thought to be a symbol of a high risk of recurrent ischemic stroke (IS). A few researchers have found that the presence of CMBs has no significant effect on the prognosis of patients with AIS. Therefore, the current views on the role of CMBs in the prognoses of patients with IS are controversial. The use of anticoagulants and other drugs has also become a dilemma due to the special influence of CMBs on the prognosis of these patients. Due to the large number of patients with AF and CMBs, many studies have been conducted on the effects of CMBs on these patients and subsequent pharmacological treatments. However, at present, there are no relevant guidelines to guide the secondary preventive treatment of patients with stroke, CMBs, and AF. In this paper, we summarized the role of CMBs in AIS combined with AF and relevant preventive measures against the recurrence of stroke and the occurrence of intracerebral hemorrhage to help clarify the specifics of drug therapies for this group of patients.

Five-Year Impacts of Antithrombotic Therapy Based on 10-Year Clinical Outcomes of Cypher™ Stent Implantation

Introduction

Few researchers have investigated the optimal long-term antithrombotic therapy regimen, especially after first-generation drug-eluting stent (DES) use. This study aimed to evaluate the impact of mid-term antithrombotic therapy on long-term outcomes in patients treated with the first sirolimus-eluting coronary stent (Cypher™).

Methods

Between 2004 and 2009, 1021 patients underwent Cypher™ implantation at our institute; among them, 567 patients had available data on antithrombotic therapy at year 5. We assessed patients’ antithrombotic therapy at year 5 post Cypher™ implantation and examined their association with adverse events from year 5 to year 10 post Cypher™ implantation.

Results

Patients with dual-antiplatelet therapy (DAPT) at year 5 had significantly lower risk of stent thrombosis (ST) than those with single-antiplatelet therapy (SAPT) (hazard ratio [HR] 0.24, p = 0.034). The HR of major bleeding in DAPT, compared to SAPT, was high, but the difference was not significant (HR 1.72, p = 0.26). Risk of major bleeding was significantly higher in patients on oral anticoagulants (OAC) than in those in other groups (OAC/SAPT; HR 5.31, p = 0.0048, OAC/DAPT; HR 3.08, p = 0.022), without significant reduction in the risk of cardiovascular events.

Conclusions

The incidence of ST after Cypher™ implantation in patients with DAPT at year 5 was significantly lower than that in SAPT. However, the risk of bleeding was higher with DAPT than with SAPT. Moreover, the risk of major bleeding was significantly higher in patients on anticoagulant therapy than in other patients. New options for the use of antithrombotic drugs after percutaneous coronary intervention warrant further studies on the optimal antithrombotic therapy for first-generation DES.

Left Ventricular Thrombus Following Acute Myocardial Infarction: JACC State-of-the-Art Review

The incidence of left ventricular (LV) thrombus following acute myocardial infarction has markedly declined in recent decades caused by advancements in reperfusion and antithrombotic therapies. Despite this, embolic events remain the most feared complication of LV thrombus necessitating systemic anticoagulation. Mechanistically, LV thrombus development depends on Virchow's triad (ie, endothelial injury from myocardial infarction, blood stasis from LV dysfunction, and hypercoagulability triggered by inflammation, with each of these elements representing potential therapeutic targets). Diagnostic modalities include transthoracic echocardiography with or without ultrasound-enhancing agents and cardiac magnetic resonance. Most LV thrombi develop within the first 2 weeks post-acute myocardial infarction, and the role of surveillance imaging appears limited. Vitamin K antagonists remain the mainstay of therapy because the efficacy of direct oral anticoagulants is less well established. Only meager data support the routine use of prophylactic anticoagulation, even in high-risk patients.

Atherothrombotic factors and atherosclerotic cardiovascular events: the multi-ethnic study of atherosclerosis

AIMS

Traditional atherosclerotic cardiovascular disease (ASCVD) risk factors fail to address the full spectrum of the complex interplay of atherosclerotic and atherothrombotic factors integral to ASCVD events. This study sought to examine the association between atherothrombotic biomarkers and ASCVD events.

METHODS AND RESULTS

The association between atherothrombotic biomarkers and 877 ASCVD events with and without adjustment for traditional risk factors was evaluated via Cox proportional hazards models and factor analysis in 5789 Multi-Ethnic Study of Atherosclerosis participants over a median follow-up of 14.7 years. Factor analysis accounted for multidimensional relationship and shared variance among study biomarkers, which identified two new variables: a thrombotic factor (Factor 1), principally defined by shared variance in fibrinogen, plasmin-antiplasmin complex, factor VIII, D-dimer, and lipoprotein(a), and a fibrinolytic factor (Factor 2), principally defined by shared variance of plasminogen and oxidized phospholipids on plasminogen. In a model including both factors, the thrombotic factor was associated with the higher risk of ASCVD events [hazard ratio (HR) 1.57, 95% confidence interval (CI) 1.45, 1.70], while the fibrinolytic factor was associated with the lower risk of ASCVD events (HR 0.76, 95% CI 0.70, 0.82), with estimated ASCVD free survival highest for low atherothrombotic Factor 1 and high atherothrombotic Factor 2.

CONCLUSION

Two atherothrombotic factors, one representative of thrombotic propensity and the other representative of fibrinolytic propensity, were significantly and complementarily associated with incident ASCVD events, remained significantly associated with incident ASCVD after controlling for traditional risk factors, and have promise for identifying patients at high ASCVD event risk specifically due to their atherothrombotic profile.

Left Ventricular Dysfunction Among Patients With Embolic Stroke of Undetermined Source and the Effect of Rivaroxaban vs Aspirin: A Subgroup Analysis of the NAVIGATE ESUS Randomized Clinical Trial

Importance

It is uncertain whether anticoagulation is superior to aspirin at reducing recurrent stroke in patients with recent embolic strokes of undetermined source (ESUS) and left ventricular (LV) dysfunction.

Objective

To determine whether anticoagulation is superior to aspirin in reducing recurrent stroke in patients with ESUS and LV dysfunction.

Design, Setting, and Participants

Post hoc exploratory analysis of data from the New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial vs Aspirin to Prevent Embolism in ESUS (NAVIGATE ESUS) trial, a randomized, phase 3 clinical trial with enrollment from December 2014 to September 2017. The study setting included 459 stroke recruitment centers in 31 countries. Patients 50 years or older who had neuroimaging-confirmed ESUS between 7 days and 6 months before screening were eligible. Of the 7213 NAVIGATE ESUS participants, 7107 (98.5%) had a documented assessment of LV function at study entry and were included in the present analysis. Data were analyzed in January 2021.

Interventions

Participants were randomized to receive either 15 mg of rivaroxaban or 100 mg of aspirin once daily.

Main Outcomes and Measures

The study examined whether rivaroxaban was superior to aspirin at reducing the risk of (1) the trial primary outcome of recurrent stroke or systemic embolism and (2) the trial secondary outcome of recurrent stroke, systemic embolism, myocardial infarction, or cardiovascular mortality during a median follow-up of 10.4 months. LV dysfunction was identified locally through echocardiography and defined as moderate to severe global impairment in LV contractility and/or a regional wall motion abnormality. A Cox proportional hazards model was used to assess for treatment interaction and to estimate the hazard ratios for those randomized to rivaroxaban vs aspirin by LV dysfunction status.

Results

LV dysfunction was present in 502 participants (7.1%). Of participants with LV dysfunction, the mean (SD) age was 67 (10) years, and 130 (26%) were women. Among participants with LV dysfunction, annualized primary event rates were 2.4% (95% CI, 1.1-5.4) in those assigned to rivaroxaban vs 6.5% (95% CI, 4.0-11.0) in those assigned aspirin. Among the 6605 participants without LV dysfunction, rates were similar between those assigned to rivaroxaban (5.3%; 95% CI, 4.5-6.2) vs aspirin (4.5%; 95% CI, 3.8-5.3). Participants with LV dysfunction assigned to rivaroxaban vs aspirin had a lower risk of the primary outcome (hazard ratio, 0.36; 95% CI, 0.14-0.93), unlike those without LV dysfunction (hazard ratio, 1.16; 95% CI, 0.93-1.46) (P for treatment interaction = .03). Results were similar for the secondary outcome.

Conclusions and Relevance

In this post hoc exploratory analysis, rivaroxaban was superior to aspirin in reducing the risk of recurrent stroke or systemic embolism among NAVIGATE ESUS participants with LV dysfunction.

Trial Registration

ClinicalTrials.gov Identifier: NCT02313909.

Clinical factors associated with peripheral artery disease in patients with documented coronary artery disease: A post hoc analysis of the COMPASS trial

BACKGROUND AND AIMS

Patients with coronary artery disease (CAD) who also have peripheral artery disease (PAD) are at high risk of subsequent cardiovascular events and mortality. Despite this, PAD in patients with CAD often remains undiagnosed. The objective of this analysis was to assess clinical factors that predict the presence of PAD in patient with documented CAD who also have PAD.

METHODS

In a post hoc analysis of patients with CAD in the COMPASS trial, we developed separate prediction models for symptomatic lower extremity PAD and documented carotid artery disease (Model 1), asymptomatic lower extremity PAD defined as ABI <0.9 (Model 2) and for any PAD (symptomatic or asymptomatic; Model 3). Using logistic regression models, candidate variables were chosen to predict the presence of PAD. Overall model performance was evaluated for discrimination and calibration using the concordance statistic and Hosmer and Lemeshow Goodness-of-fit chi-square, respectively. The final model was validated by bootstrapping.

RESULTS

Of 23,402 participants, 3484 (14.9%) had a history of symptomatic PAD or carotid artery disease (Model 1), 1422 (5.7%) participants had asymptomatic PAD (Model 2) and 4906 (20.6%) had any PAD (Model 3). Model 1 demonstrated a C-statistic of 0.667 and goodness-of-fit p-value of 0.859. Model 2 demonstrated a C-statistic of 0.626 and goodness-of-fit p-value of 0.250. Model 3 demonstrated a C-statistic of 0.646 and goodness-of-fit p-value of 0.240.

CONCLUSION

Routinely available clinical information is only marginally useful to identify patients with CAD and concomitant PAD.

Oral anticoagulation and outcomes in patients with acute myocardial infarction: Insights from the Hungarian Myocardial Infarction Registry

INTRODUCTION

Anticoagulation reduces the risk of stroke and embolization and is recommended in most patients with atrial fibrillation. Patients after coronary intervention and acute coronary syndromes require antiplatelet treatment. Although oral anticoagulation (OAC) therapy may interfere with the outcome of patients after coronary intervention, its exact impact remains unclear. Importantly, risk-benefit relations may be considerably different after myocardial infarction.

MATERIAL AND METHODS

Data of patients registered from the Hungarian Myocardial Infarction Registry, a mandatory nationwide program for hospitals treating patients with myocardial infarction, were processed. Patients registered between 01.2014. and 12.2017 were included. All-cause mortality, the composite of cardiac events (MACE), and transfusion were compared between patients receiving OAC treatment and a propensity score (PS) matched control group. Subgroup analyses of different anticoagulation and antiplatelet strategies were performed with propensity weighted Cox proportional hazards' models to estimate risk during the first year after the index event.

RESULTS

From 30 681 patients 1875 cases received OAC treatment and had apparently worse prognosis. After PS-matching, however, we found no difference regarding mortality (hazard ratio [HR]: 0.91 95% CI 0.77-1.09, P = .303), MACE (HR: 0.92 95% CI 0.78-1.09, P = .335) or transfusion (HR: 1.21, 95% CI 0.97-1.49, P = .086). In PS-adjusted analyses for the OAC group, patients who received aspirin were associated with lower mortality (HR: 0.77, 95% CI: 0.60-0.997, P = .048) and MACE (HR:0.73, 95% CI 0.58-0.92, P = .008) compared to those without aspirin.

CONCLUSIONS

In patients with acute myocardial infarction, the prognosis of OAC-treated patients was comparable to the PS matched control; however, the omission of aspirin therapy was associated with unfavorable outcomes.

Antithrombotic therapy in diabetes: which, when, and for how long?

Cardiovascular disease remains the main cause of mortality in individuals with diabetes mellitus (DM) and also results in significant morbidity. Premature and more aggressive atherosclerotic disease, coupled with an enhanced thrombotic environment, contributes to the high vascular risk in individuals with DM. This prothrombotic milieu is due to increased platelet activity together with impaired fibrinolysis secondary to quantitative and qualitative changes in coagulation factors. However, management strategies to reduce thrombosis risk remain largely similar in individuals with and without DM. The current review covers the latest in the field of antithrombotic management in DM. The role of primary vascular prevention is discussed together with options for secondary prevention following an ischaemic event in different clinical scenarios including coronary, cerebrovascular, and peripheral artery diseases. Antiplatelet therapy combinations as well as combination of antiplatelet and anticoagulant agents are examined in both the acute phase and long term, including management of individuals with sinus rhythm and those with atrial fibrillation. The difficulties in tailoring therapy according to the variable atherothrombotic risk in different individuals are emphasized, in addition to the varying risk within an individual secondary to DM duration, presence of complications and predisposition to bleeding events. This review provides the reader with an up-to-date guide for antithrombotic management of individuals with DM and highlights gaps in knowledge that represent areas for future research, aiming to improve clinical outcome in this high-risk population.

Considerations for use of direct oral anticoagulants in arterial disease

Cardiovascular diseases including coronary heart disease, stroke, and peripheral arterial disease were responsible for an estimated 18 million deaths in 2017. Despite advances in management over the past several decades, these patients continue to have substantial risk of subsequent cardiovascular events. We provide a narrative review of randomized clinical trials evaluating direct oral anticoagulants (DOACs) for the treatment of acute coronary syndromes, noncardioembolic ischemic stroke, embolic stroke of undetermined source, and peripheral arterial disease. In these conditions, considerations for use of single antiplatelet therapy, dual antiplatelet therapy, or low-dose DOACs used together with antiplatelet therapy are presented.

Features of Risk Stratification, Diagnosis and Secondary Prevention in Patients with Multifocal Arterial Disease. Part 2: Treatment Options

The similarity of the pathogenesis of atherosclerosis and atherothrombotic complications, regardless of their location, makes the approaches to secondary prevention similar, which include lifestyle modification, pharmacotherapy of hemodynamic disorders, metabolic changes and hemostasis. Secondary prophylaxis in patients with multifocal arterial lesions using antihypertensive, antithrombotic and lipid-lowering therapy provides a more pronounced decrease in the incidence of cardiovascular complications than in lesions of single vascular lesions due to a higher initial risk. However, these treatments do not reduce the risk to the level that is achieved by treating patients with less atherosclerotic lesion. In this regard, it is of interest to use the currently available new methods and regimens of drug therapy in patients with multifocal arterial lesions, which make it possible to more intensively influence the mechanisms of atherosclerosis progression and more effectively prevent the development of its complications.

Antithrombotic Management of Elderly Patients With Coronary Artery Disease

Antithrombotic therapy represents the mainstay of treatment in patients with coronary artery disease (CAD), including elderly patients who are at increased risk for ischemic recurrences. However, the elderly population is also more vulnerable to bleeding complications. Numerous mechanisms, including abnormalities in the vasculature, thrombogenicity, comorbidities, and altered drug response, contribute to both increased thrombotic and bleeding risk. Age-related organ changes and drug-drug interactions secondary to polypharmacy lead to distinct pharmacokinetic and pharmacodynamic profiles of antithrombotic drugs. Overall these factors contribute to the risk-benefit profiles of antithrombotic therapies in elderly subjects and underscore the need for treatment regimens that can reduce bleeding while preserving efficacy. Given that the prevalence of CAD, as well as concomitant diseases with thromboembolic potential, such as atrial fibrillation, increases with age and that the elderly population is in continuous growth, understanding the safety and efficacy of different antithrombotic regimens is pivotal for patient-centered care. In the present overview the authors appraise the available data on the use of antithrombotic therapy in older patients with CAD to assist with the management of this high-risk population and define knowledge gaps that can set the basis for future research.

Features of Antithrombotic Therapy in Patients with Multifocal Arterial Disease

Multifocal arterial injury is common in patients with atherosclerotic cardiovascular diseases and is associated with increased risk of cardiovascular complications and death. Administration of more intensive antithrombotic therapy, particularly combinations of acetylsalicylic acid and a "vascular" dose of rivaroxaban, in patients with multifocal arterial injury is characterized by a beneficial ratio of efficiency and safety due to a pronounced decrease in the risk of cardiovascular complications. Detection of peripheral artery diseases in patients with ischemic heart disease and atherosclerotic cerebrovascular pathology makes it possible to improve the risk stratification, optimize the diagnostic tactics and clarify indications for more intensive antithrombotic therapy.

Myocardial Infarction Complicated by Ischemic Stroke: Risk Factors, Prognosis, Unresolved Problems and Possible Methods of Prevention

The present work is devoted to the analysis of modern publications on various aspects of the development and course of ischemic stroke in the presence of acute myocardial infarction. A literature search was conducted on the websites of cardiological and neurological societies, as well as on the PubMed, EMBASE, eLibrary databases using the keywords: myocardial infarction, acute coronary syndrome, stroke, acute cerebrovascular accident, myocardial infarction, acute coronary syndrome, stroke. The authors of this review found that although stroke is a relatively rare complication of myocardial infarction, its prevention is an extremely significant task, since it is associated with high mortality, disability and a significant increase in the cost of treatment. So, it is extremely important to detect thrombosis of the left ventricular cavity in a timely manner, to register preexisting atrial fibrillation that occurs earlier or for the first time, followed by the appointment of anticoagulant therapy. Timely reperfusion treatment, the use of statins and modern dual antithrombotic therapy can reduce the risk of developing cerebrovascular accident in patients with myocardial infarction. It is likely that a decrease in the activity of subclinical inflammation after myocardial infarction will also reduce the risk of stroke, as was recently shown in the COLCOT study. Currently, it remains relevant to search for new knowledge about the risk factors for stroke, which complicated the course of myocardial infarction, which will allow developing more effective and personalized preventive measures in a patient with acute coronary syndrome.

Safety and efficacy of P2Y12 inhibitor monotherapy in patients undergoing percutaneous coronary interventions

Introduction: Antiplatelet therapy represents a key strategy for the prevention of thrombotic complications in patients with both acute and chronic coronary syndromes, particularly those undergoing percutaneous coronary intervention (PCI). Nevertheless, dual antiplatelet therapy (DAPT) is associated with a bleeding risk proportionate to its duration. Ever growing appreciation of the prognostic implications associated with bleeding and the development of safer stent platforms over the past years have led to a number of novel antiplatelet treatment strategies being tested among patients undergoing PCI. Areas covered: P2Y₁₂ inhibitor monotherapy after ashort course DAPT has emerged as ableeding reduction strategy to mitigate such risk while still preventing thrombotic complications. In this review we describe the latest evidence regarding the safety and efficacy of P2Y₁₂ inhibitor monotherapy in patients undergoing PCI in different clinical settings. Expert opinion: P2Y₁₂ inhibitor monotherapy after a brief period of DAPT has emerged as an effective approach to reduce the risk of bleeding without any tradeoff in efficacy (i.e., thrombotic complications). This strategy has shown consistent findings in a number of different clinical settings of patients undergoing PCI. Nevertheless, unanswered questions on the ideal patient and the precise P2Y₁₂ monotherapy regimen warrant further investigation.

Antithrombotic Effects of Combined PAR (Protease-Activated Receptor)-4 Antagonism and Factor Xa Inhibition

OBJECTIVE

PAR (protease-activated receptor)-4 antagonism has antiplatelet effects under conditions of high shear stress. We aimed to establish whether PAR4 antagonism had additive antithrombotic activity in the presence of factor Xa inhibition in an ex vivo model of acute arterial injury. Approach and Results: Fifteen healthy volunteers (29±6 years, 7 women) completed a phase zero double-blind randomized controlled crossover trial. Ex vivo platelet activation, platelet aggregation, and thrombus formation were measured following blood perfusion of low shear and high shear stress chambers. Upstream of the chambers, extracorporeal blood was admixed with (1) vehicle, (2) low-dose apixaban (20 ng/mL), (3) high-dose apixaban (80 ng/mL), (4) BMS-986141 (400 ng/mL), (5) BMS-968141 and low-dose apixaban, or (6) BMS-968141 and high-dose apixaban in 6 sequential studies performed in random order. Compared with vehicle, BMS-986141 demonstrated selective inhibition of PAR4-AP (agonist peptide)-stimulated platelet aggregation, platelet-monocyte aggregates, and P-selectin expression (P≤0.01 for all). Total thrombus area was reduced under both low shear and high shear stress conditions for all drug infusions (P<0.0001 for all versus vehicle). BMS-968141 reduced total (≤44.4%) and platelet-rich (≤39.3%) thrombus area, whereas apixaban reduced total (≤42.9%) and fibrin-rich (≤31.6%) thrombus area. Combination of BMS-986141 with apixaban caused a further modest reduction in total thrombus area (9.6%-12.4%), especially under conditions of high shear stress (P≤0.027).

CONCLUSIONS

In the presence of factor Xa inhibition, PAR4 antagonism with BMS-986141 further reduces thrombus formation, especially under conditions of high shear stress. This suggests the potential for additive efficacy of combination PAR4 antagonism and factor Xa inhibition in the prevention of atherothrombotic events.

Proton Pump Inhibitor Utilization in Veteran Patients on Combined Antithrombotic Therapy and Validation of Simplified Bleeding Risk Score

BACKGROUND

Concomitant use of anticoagulant and antiplatelet agents can increase the risk of gastrointestinal bleed (GIB). Use of proton pump inhibitors (PPIs) has been proposed to decrease the risk of GIB in patients on combined antithrombotic therapy (CAT).

OBJECTIVE

To describe the current utilization of PPIs in veteran patients on CAT and associated clinical predictors of GIB.

METHODS

This retrospective study included patients on CAT receiving PPIs, with at least one of the CAT agents initiated between January 1, 2018 and October 30, 2018. Data were extracted from the computerized patient record system. Primary end point included estimating proportion of patients on CAT receiving PPI co-therapy, describing patient characteristics, and identifying clinical predictors of GIB. Secondary outcomes included reporting GIB events and all-cause mortality. Additional outcome was to validate the five-factor risk score (FFRS) for GIB in patients on CAT and compare its overall predictive performance to HAS-BLED score.

RESULTS

This study reports an overall rate of PPI co-therapy in patients on CAT of 40.9% (484/1181), with only 22.3% of patients on CAT receiving PPI for GIB prophylaxis. There was no difference in the mean follow up duration of PPI users and PPI co-therapy (264.01 vs 271.92 days; p=0.3761). Current alcohol use (p=0.005), current smokers (p=0.022), chronic kidney disease (p=0.004), peptic ulcer disease (p<0.001), and non-steroidal anti-inflammatory drug use (p=0.048) were significant predictors of GIB in multivariate analyses of our study cohort. We further provide exploratory validation that use of a simplified FFRS to predict GIB showed a trend towards better overall predictive performance as compared to HAS-BLED score (C-statistic: 0.738; 95% CI 0.684-0.787 for FFRS vs C-statistic: 0.596; 95% CI 0.538-0.653 for HAS-BLED; p=0.0094).

CONCLUSION

This study reports lower rate of PPI co-therapy in veteran patients on CAT per currently available guidance. Further we explore utilization of simplified FFRS model to predict GIB in patients on CAT with long-term PPI co-therapy.

Pleiotropic actions of factor Xa inhibition in cardiovascular prevention: mechanistic insights and implications for anti-thrombotic treatment

Atherosclerosis is a chronic inflammatory disease in which atherothrombotic complications lead to cardiovascular morbidity and mortality. At advanced stages, myocardial infarction, ischaemic stroke, and peripheral artery disease, including major adverse limb events, are caused either by acute occlusive atherothrombosis or by thromboembolism. Endothelial dysfunction, vascular smooth muscle cell activation, and vascular inflammation are essential in the development of acute cardiovascular events. Effects of the coagulation system on vascular biology extend beyond thrombosis. Under physiological conditions, coagulation proteases in blood are pivotal in maintaining haemostasis and vascular integrity. Under pathological conditions, including atherosclerosis, the same coagulation proteases (including factor Xa, factor VIIa, and thrombin) become drivers of atherothrombosis, working in concert with platelets and vessel wall components. While initially atherothrombosis was attributed primarily to platelets, recent advances indicate the critical role of fibrin clot and plasma coagulation factors. Mechanisms of atherothrombosis and hypercoagulability vary depending on plaque erosion or plaque rupture. In addition to contributing to thrombus formation, factor Xa and thrombin can affect endothelial dysfunction, oxidative stress, vascular smooth muscle cell function as well as immune cell activation and vascular inflammation. By these mechanisms, they promote atherosclerosis and contribute to plaque instability. In this review, we first discuss the postulated vasoprotective mechanisms of protease-activated receptor signalling induced by coagulation enzymes under physiological conditions. Next, we discuss preclinical studies linking coagulation with endothelial cell dysfunction, thromboinflammation, and atherogenesis. Understanding these mechanisms is pivotal for the introduction of novel strategies in cardiovascular prevention and therapy. We therefore translate these findings to clinical studies of direct oral anticoagulant drugs and discuss the potential relevance of dual pathway inhibition for atherothrombosis prevention and vascular protection.

Rivaroxaban in Acute Coronary Syndromes: We Have a Compass and an Atlas, But Where Are We Headed?

See Article by Gibson et al

Predicted effect of ticagrelor on the pharmacokinetics of dabigatran etexilate using physiologically based pharmacokinetic modeling

Dabigatran etexilate (DABE) is a direct oral anticoagulant (DOAC) and may be combined with ticagrelor, a P2Y₁₂ inhibitor with antiplatelet effects. This combination of antiplatelet drugs and anticoagulants would increases the risk of bleeding in patients. In addition, the potential drug interaction may further increase the risk of bleeding. At present, there is scarce research to clarify the results of the interaction between the two. Therefore, we conducted this study to identify the potential impact of ticagrelor on the pharmacokinetics of DABE using physiologically based pharmacokinetic (PBPK) modeling. The models reasonably predicted the concentration-time profiles of dabigatran (DAB), the transformation form after DABE absorption, and ticagrelor. For pharmacokinetic drug-drug interaction (DDI), exposure to DAB at steady state was increased when co-administrated with ticagrelor. The C_max and AUC_0-t of DAB were raised by approximately 8.7% and 7.1%, respectively. Meanwhile, a stable-state ticagrelor co-administration at 400 mg once-daily increased the C_max and AUC_0-t of DAB by approximately 12.8% and 18.8%, respectively. As conclusions, Ticagrelor slightly increased the exposure of DAB. It is possible to safely use ticagrelor in a double or triple antithrombotic regimen containing DABE, only considering the antithrombotic efficacy, but not need to pay much attention on the pharmacokinetic DDI.

Combination Antiplatelet and Oral Anticoagulant Therapy in Patients With Coronary and Peripheral Artery Disease

Antiplatelet therapy is the mainstay for the treatment of acute and chronic arterial disease involving the coronary and peripheral beds. However, questions remain about optimal antithrombotic therapy for long-term treatment of chronic vascular disease. The observation that dual antiplatelet therapy with acetylsalicylic acid and clopidogrel was associated with lower thrombotic event rates than acetylsalicylic acid monotherapy in patients with acute coronary syndromes and those undergoing percutaneous coronary intervention changed the treatment paradigm. Moreover, the demonstration that more pharmacodynamically potent P2Y₁₂ inhibitors than clopidogrel were associated with fewer thrombotic event occurrences further solidified the dual antiplatelet therapy approach. However, recurrent thrombotic events occur in ≈1 in 10 patients in the first year following an acute coronary syndrome event, despite treatment with the most potent P2Y₁₂ inhibitors, a limitation that has stimulated interest in exploring the efficacy and safety of approaches using anticoagulants on top of antiplatelet therapy. These investigations have included treatment with very-low-dose oral anticoagulation, and even its replacement of acetylsalicylic acid in the presence of a P2Y₁₂ inhibitor, in patients stabilized after an acute coronary syndrome event. Recent basic and translational studies have suggested noncanonical effects of coagulation factor inhibition that may further modulate clinical benefits. This in-depth review will discuss developments in our understanding of the roles that platelets and coagulation factors play in atherothrombosis and review the rationale and clinical evidence for combining antiplatelet and oral anticoagulant therapy in patients with coronary and peripheral artery disease.

Dual-pathway inhibition for secondary and tertiary antithrombotic prevention in cardiovascular disease

Advances in antiplatelet therapies for patients with cardiovascular disease have improved patient outcomes over time, but the challenge of balancing the risks of ischaemia and bleeding remains substantial. Moreover, many patients with cardiovascular disease have a residual risk of ischaemic events despite receiving antiplatelet therapy. Therefore, novel strategies are needed to prevent clinical events through mechanisms beyond platelet inhibition and with an acceptable associated risk of bleeding. The advent of non-vitamin K antagonist oral anticoagulants, which attenuate fibrin formation by selective inhibition of factor Xa or thrombin, has renewed the interest in dual-pathway inhibition strategies that combine an antiplatelet agent with an anticoagulant drug. In this Review, we highlight the emerging pharmacological rationale and clinical development of dual-pathway inhibition strategies for the prevention of atherothrombotic events in patients with different manifestations of cardiovascular disease, such as coronary artery disease, cerebrovascular disease and peripheral artery disease.

Non-vitamin K antagonist oral anticoagulants (NOACs) post-percutaneous coronary intervention: a network meta-analysis

BACKGROUND

Clinicians must balance the risks of bleeding and thrombosis after percutaneous coronary intervention (PCI) in people with an indication for anticoagulation. The potential of non-vitamin K antagonists (NOACs) to prevent bleeding complications is promising, but evidence remains limited.

OBJECTIVES

To review the evidence from randomised controlled trials assessing the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) compared to vitamin K antagonists post-percutaneous coronary intervention (PCI) in people with an indication for anticoagulation.

SEARCH METHODS

We identified studies by searching CENTRAL, MEDLINE, Embase, the Conference Proceedings Citation Index - Science and two clinical trials registers in February 2019. We checked bibliographies of identified studies and applied no language restrictions.

SELECTION CRITERIA

We searched for randomised controlled trials (RCT) that compared NOACs and vitamin K antagonists for people with an indication for anticoagulation who underwent PCI.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked the results of searches to identify relevant studies, assessed each included study, and extracted study data. We conducted random-effects, pairwise analyses using Review Manager 5 and network meta-analyses (NMA) using the R package 'netmeta'. We ranked competing treatments by P scores, which are derived from the P values of all pairwise comparisons, and allow ranking of treatments on a continuous 0 to 1 scale.

MAIN RESULTS

We identified nine RCTs that met the inclusion criteria, but four were ongoing trials, and were not included in this analysis. We included five RCTs, with 8373 participants, in the NMA (two RCTs compared apixaban to a vitamin K antagonist, two RCTs compared rivaroxaban to a vitamin K antagonist, and one RCT compared dabigatran to a vitamin K antagonist). Very low- to moderate-certainty evidence suggests little or no difference between NOACs and vitamin K antagonists in death from cardiovascular causes (not reported in the dabigatran trial), myocardial infarction, stroke, death from any cause, and stent thrombosis. Apixaban (RR 0.85, 95% CI 0.77 to 0.95), high dose rivaroxaban (RR 0.86, 95% CI 0.74 to 1.00), and low dose rivaroxaban (RR 0.80, 95% CI 0.68 to 0.92) probably reduce the risk of recurrent hospitalisation compared with vitamin K antagonists. No studies looked at health-related quality of life. Very low- to moderate-certainty evidence suggests that NOACs may be safer than vitamin K antagonists in terms of bleeding. Both high dose dabigatran (RR 0.53, 95% CI 0.29 to 0.97), and low dose dabigatran (RR 0.38, 95% CI 0.21 to 0.70) may reduce major bleeding more than vitamin K antagonists. High dose dabigatran (RR 0.83, 95% CI 0.72 to 0.96), low dose dabigatran (RR 0.66, 95% CI 0.58 to 0.75), apixaban (RR 0,67 , 95% Cl 0.51 to 0.88), high dose rivaroxaban (RR 0.66, 95% CI 0.52 to 0.83), and low dose rivaroxaban (RR 0.71, 95% CI 0.57 to 0.88) probably reduce non-major bleeding more than vitamin K antagonists. The results from the NMA were inconclusive between the different NOACs for all primary and secondary outcomes.

AUTHORS' CONCLUSIONS

Very low- to moderate-certainty evidence suggests no meaningful difference in efficacy outcomes between non-vitamin K antagonist oral anticoagulants (NOAC) and vitamin K antagonists following percutaneous coronary interventions (PCI) in people with non-valvular atrial fibrillation. NOACs probably reduce the risk of recurrent hospitalisation for adverse events compared with vitamin K antagonists. Low- to moderate-certainty evidence suggests that dabigatran may reduce the rates of major and non-major bleeding, and apixaban and rivaroxaban probably reduce the rates of non-major bleeding compared with vitamin K antagonists. Our network meta-analysis did not show superiority of one NOAC over another for any of the outcomes. Head to head trials, directly comparing NOACs against each other, are required to provide more certain evidence.

Applying contemporary antithrombotic therapy in the secondary prevention of chronic atherosclerotic cardiovascular disease

For 4 decades, antithrombotic therapy with aspirin has been a cornerstone of secondary prevention for patients with chronic atherosclerotic cardiovascular disease (ASCVD). Unfortunately, despite the use of evidence-based therapies, patients with ASCVD continue to have recurrent major adverse cardiovascular events including death, myocardial infarction, and stroke-at a rate of approximately 2%-4% per year. To combat this continuing risk, several recent trials have evaluated the efficacy and safety of more intensive antithrombotic strategies through prolonged dual antiplatelet therapy (DAPT), combining a P2Y12 receptor antagonists and low-dose aspirin, or alternatively applying a dual pathway inhibition approach, combining low-dose non-vitamin K antagonist anticoagulant and low-dose aspirin. Both combination strategies have been shown to reduce recurrent ischemic events but at the cost of increased bleeding events. The clinical application of these antithrombotic strategies requires clinicians to assess and balance the risk of recurrent ischemic and bleeding events in an individual patient. Furthermore, clinicians may also need to adapt their antithrombotic strategies to achieve best patient outcomes, as ASCVD is a progressive disease and the risks of cardiovascular ischemic and bleeding events may shift over time. This state-of-the-art article reviews evidence from the trials and provides a practical approach to the application of DAPT and dual pathway antithrombotic therapy in the long-term management of patients with chronic ASCVD.

Clinical consequences of bleeding among individuals with a recent acute coronary syndrome: Insights from the APPRAISE-2 trial

Patients with a recent acute coronary syndrome (ACS) receiving oral antiplatelets and anticoagulants are at risk for bleeding and subsequent adverse non-bleeding-related events.

METHODS

In this post hoc analysis, we evaluated 7,392 high-risk patients (median follow-up 241 days) with a recent ACS randomized to apixaban or placebo in APPRAISE-2. Clinical events during a 30-day period after Thrombolysis in Myocardial Infarction (TIMI) major/minor bleeding were analyzed using unadjusted and adjusted Cox proportional-hazards models.

RESULTS

In total, 153 (2.1%) patients experienced TIMI major/minor bleeding during follow-up. Bleeding risk for patients on triple therapy (apixaban, thienopyridine, and aspirin) was increased compared with those on dual therapy (apixaban plus aspirin: hazard ratio [HR] 2.02, 95% CI 1.08-3.79; thienopyridine plus aspirin: HR 1.99, 95% CI 1.41-2.83). Those receiving apixaban/aspirin had similar bleeding risk compared with those receiving thienopyridine/aspirin (HR 1.01, 95% CI 0.53-1.95). Patients who experienced TIMI major/minor bleeding had an increased risk of 30-day all-cause mortality (HR 24.7, 95% CI 15.34-39.66) and ischemic events (HR 6.7, 95% CI 3.14-14.14).

CONCLUSIONS

In a contemporary cohort of high-risk patients after ACS, bleeding was associated with a significantly increased risk of subsequent ischemic events and mortality regardless of antithrombotic or anticoagulant strategy. Patients receiving apixaban plus aspirin had a similar bleeding risk compared with those receiving thienopyridine plus aspirin. Interventions to improve outcomes in patients after ACS should include strategies to optimize the reduction in ischemic events while minimizing the risk of bleeding.

Development of New Antithrombotic Regimens for Patients with Acute Coronary Syndrome

Patients with acute coronary syndrome (ACS) require long-term antithrombotic intervention to reduce the risk of further ischemic events; dual antiplatelet therapy with a P2Y₁₂ inhibitor and acetylsalicylic acid (ASA) is the current standard of care. However, pivotal clinical trials report that patients receiving this treatment have a residual risk of approximately 10% for further ischemic events. The development of non-vitamin K antagonist oral anticoagulants (NOACs) has renewed interest in a 'dual pathway' strategy, targeting both the coagulation cascade and platelet component of thrombus formation. In the phase III ATLAS ACS 2 TIMI 51 trial, a 'triple therapy' approach (NOAC plus dual antiplatelet therapy) showed reduced ischemic events with rivaroxaban 2.5 mg twice daily, albeit at an increased risk of bleeding. Two studies have investigated the role of NOACs in combination with a P2Y₁₂ inhibitor, with or without ASA, in reducing bleeding risk in patients with atrial fibrillation undergoing percutaneous coronary intervention; two further studies are underway. Although these trials will help to inform optimal treatment protocols for secondary prevention of ACS, an individualized approach to treatment will be needed, taking account of the high frequency of co-morbid conditions found in this patient population.

French vascular physicians' practices in indicating antiplatelet and anticoagulation therapy in venous thromboembolism

Background: As antiplatelet therapy becomes widespread, physicians face the issue patients being treated with antiplatelet agents (APA) and anticoagulants for venous thromboembolism (VTE). Bleeding risk of this combination is increased 1.5-2.5-fold. The aim of this survey is to assess French vascular physician's management of this combination at the beginning of the treatment and at 6 months of treatment for VTE. Patients and methods: French vascular physicians were surveyed between September and December 2017, using 4 fictional scenarios regarding a VTE event diagnosed in a patient under antiplatelet therapy plus isolated questions in an online questionnaire, sent by the French Society of Vascular Medicine to its members. Out of 1812 physicians, 179 returned valid questionnaires: the response rate was 9.9%. Results: Firstly 97.2% of respondents acknowledged extra risk with this combination; and 63% ceased antiplatelet therapy when initiating anticoagulants; while 36% did not. Secondly, four strategies emerged: 31.4% ceased APA and prescribed full-dose anticoagulants at initiation and at 6 months; 32% associated reduced-dose anticoagulation with APA at 6 months, regardless of what they decided at initiation; 16.5% prescribed isolated full-dose anticoagulants at initiation and reduced-dose at 6 months; lastly 11.2% associated full-dose anticoagulant with antiplatelet therapy at initiation and at 6 months. Conclusions: French vascular physicians adopted different strategies according to estimated risk/benefit ratio. Prospective randomized controlled trials should compare these strategies in order to make recommendations.

Direct Oral Anticoagulants in Addition to Antiplatelet Therapy for Secondary Prevention after Acute Coronary Syndromes: a Review

PURPOSE OF REVIEW

As the management of acute coronary syndrome (ACS) continues to evolve, many old practices proved to be of a little benefit and other approaches established the new pillars of modern medicine. Treating ACS patients with dual antiplatelet therapy (DAPT) for a year by combining aspirin and a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) has resulted in better outcomes and is currently the standard of therapy. However, owing to the persistent activation of the coagulation cascade, patients may continue to experience recurrent ischemia and high mortality rates despite compliance with the dual antiplatelet therapy. Research is underway to establish new treatment modalities for secondary prevention post-ACS, including the use of the novel direct oral anticoagulants (DOACs).

RECENT FINDINGS

Multiple trials have been conducted to evaluate the use of DOACs for the secondary prevention after ACS. Recent emerging data showed that the addition of rivaroxaban in a very low dose of 2.5 mg twice daily to the regular DAPT regimen after ACS is beneficial in the reduction of major cardiovascular events, including recurrent myocardial infarction (MI) and strokes. On the other hand, other DOACs, including apixaban, did not show similar efficacy and did not improve the cardiovascular outcomes. Patients who experience an ACS continue to suffer long-term consequences and thromboembolic complications. Many studies have shown that after the initial ACS event, patients remain in a hypercoagulable state and are more prone to recurrent ischemic attacks including stroke, recurrent MI, or unstable angina (UA). With the objective of seeking better outcomes, it is imperative to explore more aggressive anticoagulation strategies in ACS patients. In this article, we discuss the progress that was made and the limitations we face regarding the role of different anticoagulants in this setting.

Oral anticoagulant use in cardiovascular disorders: a perspective on present and potential indications for rivaroxaban

BACKGROUND

Four non-vitamin-K-antagonist oral anticoagulants (NOACs) have been approved for use in various cardiovascular indications. The direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors apixaban, edoxaban and rivaroxaban are now increasingly used in clinical practice. For some of these agents, available data from real-world studies support the efficacy and safety data in phase III clinical trials.

OBJECTIVES

This review aims to summarize the current status of trials and observational studies of oral anticoagulant use over the spectrum of cardiovascular disorders (excluding venous thrombosis), provide a reference source beyond stroke prevention for atrial fibrillation (AF) and examine the potential for novel applications in the cardiovascular field.

METHODS

We searched the recent literature for data on completed and upcoming trials of oral anticoagulants with a particular focus on rivaroxaban.

RESULTS

Recent data in specific patient subgroups, such as patients with AF undergoing catheter ablation or cardioversion, have led to an extended approval for rivaroxaban, whereas the other NOACs have ongoing or recently completed trials in this setting. However, there are unmet medical needs for several arterial thromboembolic-related conditions, including patients with: AF and acute coronary syndrome, AF and coronary artery disease undergoing elective percutaneous coronary intervention, coronary artery disease and peripheral artery disease, implanted cardiac devices, and embolic stroke of unknown source.

CONCLUSION

NOACs may provide alternative treatment options in areas of unmet need, and numerous studies are underway to assess their benefit-risk profiles in these settings.

Clinical effects with inhibition of multiple coagulative pathways in patients admitted for acute coronary syndrome

Platelets and the coagulation cascade play key roles in initiation, amplification, and perpetuation of acute coronary syndromes (ACS). In the past few years, there has been great progress in ACS antithrombotic treatment with the introduction of novel anticoagulants (fondaparinux and bivalirudin), more potent P2Y₁₂ inhibitors (prasugrel and ticagrelor) and protease-activated receptor antagonists (vorapaxar). Nonetheless, patients with ACS frequently have recurrent ischemic events despite the use of currently recommended dual antiplatelet therapy, revascularization procedures as appropriate, and other evidence-based secondary preventive measures. This is the rationale beyond intensification of antiplatelet therapy. However, the major downside of intensive antithrombotic therapy is bleeding. When treating ACS patients, clinicians should find the adequate balance between the reduction of thrombotic events by effective drug treatment and the induction of bleeding that is linked to the use of potent or multiple antithrombotic agents. Numerous antithrombotic cocktails including oral anticoagulants with or without aspirin have been tested in large clinical trials with the goal of further reduction of ischemia and bleeding risk. The aim of this review is to discuss clinical outcomes resulting from inhibition of multiple coagulative pathways in patients with ACS in light of evidence from large randomized controlled clinical trials.

The Role of Direct Oral Anticoagulants in Patients With Coronary Artery Disease

Despite contemporary management, patients with coronary artery disease (CAD) remain at high risk for thrombotic events. Several randomized controlled trials have evaluated the use of direct oral anticoagulants (DOACs) in patients with CAD, including in the setting of acute coronary syndrome (ACS) and stable CAD, and in patients with concomitant atrial fibrillation. Trials of apixaban and dabigatran in patients with ACS demonstrate no benefit with an increased risk of bleeding. Conversely, rivaroxaban at a reduced dose of 2.5 mg twice daily reduced thrombotic events and all-cause mortality when added to dual antiplatelet therapy in patients with ACS. Similarly, the addition of low-dose rivaroxaban to acetylsalicylic acid reduced the risk of thrombotic events in patients with stable CAD. However, the addition of a DOAC to antiplatelet therapy increased the risk of major bleeding. In patients with atrial fibrillation undergoing percutaneous coronary intervention, dual-pathway or low-dose triple therapy regimens including dabigatran or rivaroxaban reduced bleeding risk compared to traditional warfarin-based triple therapy, although it remains unclear whether these regimens preserve antithrombotic efficacy. DOAC-based antithrombotic regimens prove useful in patients with CAD in various settings; however, careful selection of patients and regimens per trial protocols are critical to achieving net benefit.

Dabigatran in patients with myocardial injury after non-cardiac surgery (MANAGE): an international, randomised, placebo-controlled trial

BACKGROUND

Myocardial injury after non-cardiac surgery (MINS) increases the risk of cardiovascular events and deaths, which anticoagulation therapy could prevent. Dabigatran prevents perioperative venous thromboembolism, but whether this drug can prevent a broader range of vascular complications in patients with MINS is unknown. The MANAGE trial assessed the potential of dabigatran to prevent major vascular complications among such patients.

METHODS

In this international, randomised, placebo-controlled trial, we recruited patients from 84 hospitals in 19 countries. Eligible patients were aged at least 45 years, had undergone non-cardiac surgery, and were within 35 days of MINS. Patients were randomly assigned (1:1) to receive dabigatran 110 mg orally twice daily or matched placebo for a maximum of 2 years or until termination of the trial and, using a partial 2-by-2 factorial design, patients not taking a proton-pump inhibitor were also randomly assigned (1:1) to omeprazole 20 mg once daily, for which results will be reported elsewhere, or matched placebo to measure its effect on major upper gastrointestinal complications. Research personnel randomised patients through a central 24 h computerised randomisation system using block randomisation, stratified by centre. Patients, health-care providers, data collectors, and outcome adjudicators were masked to treatment allocation. The primary efficacy outcome was the occurrence of a major vascular complication, a composite of vascular mortality and non-fatal myocardial infarction, non-haemorrhagic stroke, peripheral arterial thrombosis, amputation, and symptomatic venous thromboembolism. The primary safety outcome was a composite of life-threatening, major, and critical organ bleeding. Analyses were done according to the intention-to-treat principle. This trial is registered with ClinicalTrials.gov, number NCT01661101.

FINDINGS

Between Jan 10, 2013, and July 17, 2017, we randomly assigned 1754 patients to receive dabigatran (n=877) or placebo (n=877); 556 patients were also randomised in the omeprazole partial factorial component. Study drug was permanently discontinued in 401 (46%) of 877 patients allocated to dabigatran and 380 (43%) of 877 patients allocated to placebo. The composite primary efficacy outcome occurred in fewer patients randomised to dabigatran than placebo (97 [11%] of 877 patients assigned to dabigatran vs 133 [15%] of 877 patients assigned to placebo; hazard ratio [HR] 0·72, 95% CI 0·55-0·93; p=0·0115). The primary safety composite outcome occurred in 29 patients (3%) randomised to dabigatran and 31 patients (4%) randomised to placebo (HR 0·92, 95% CI 0·55-1·53; p=0·76).

INTERPRETATION

Among patients who had MINS, dabigatran 110 mg twice daily lowered the risk of major vascular complications, with no significant increase in major bleeding. Patients with MINS have a poor prognosis; dabigatran 110 mg twice daily has the potential to help many of the 8 million adults globally who have MINS to reduce their risk of a major vascular complication [corrected].

FUNDING

Boehringer Ingelheim and Canadian Institutes of Health Research.

Percutaneous coronary intervention and antiplatelet therapy in patients with atrial fibrillation receiving apixaban or warfarin: Insights from the ARISTOTLE trial

BACKGROUND

We assessed antiplatelet therapy use and outcomes in patients undergoing percutaneous coronary intervention (PCI) during the ARISTOTLE trial.

METHODS

Patients were categorized based on the occurrence of PCI during follow-up (median 1.8 years); PCI details and outcomes post-PCI are reported. Of the 18,201 trial participants, 316 (1.7%) underwent PCI (152 in apixaban group, 164 in warfarin group).

RESULTS

At the time of PCI, 84% (267) were on study drug (either apixaban or warfarin). Of these, 19% did not stop study drug during PCI, 49% stopped and restarted <5 days post-PCI, and 30% stopped and restarted >5 days post-PCI. At 30 days post-PCI, 35% of patients received dual -antiplatelet therapy (DAPT), 23% received aspirin only, and 13% received a P2Y₁₂ inhibitor only; 29% received no antiplatelet therapy. Triple therapy (DAPT + oral anticoagulant [OAC]) was used in 21% of patients, 23% received OAC only, 15% received OAC plus aspirin, and 9% received OAC plus a P2Y₁₂ inhibitor; 32% received antiplatelet agents without OAC. Post-PCI, patients assigned to apixaban versus warfarin had numerically similar rates of major bleeding (5.93 vs 6.73 events/100 patient-years; P = .95) and stroke (2.74 vs 1.84 events/100 patient-years; P = .62).

CONCLUSIONS

PCI occurred infrequently during follow-up. Most patients on study drug at the time of PCI remained on study drug in the peri-PCI period; 19% continued the study drug without interruption. Antiplatelet therapy use post-PCI was variable, although most patients received DAPT. Additional data are needed to guide the use of antithrombotics in patients undergoing PCI.