Oral anticoagulants in coronary heart disease (Section IV). Position paper of the ESC Working Group on Thrombosis - Task Force on Anticoagulants in Heart Disease

Non-Vitamin K Antagonist Oral Anticoagulants in Coronary Artery Disease

The prevention of atherothrombotic events is the primary goal in the treatment of patients with arteriosclerotic disorders. Despite recent improvements in the management of coronary artery disease (CAD) with revascularization techniques and antiplatelet therapy, some patients remain at risk of recurrent cardiovascular events. This could be related to additional thrombin generation. As a result, there has been interest in developing novel therapies to prevent thromboembolic events, targeting thrombin-mediated pathways. These include non-vitamin K antagonist oral anticoagulants (NOACs). This article aims to summarize the recent clinical studies that investigated the role of NOACs in CAD.

Family history in first degree relatives of patients with premature cardiovascular disease

BACKGROUND

Family history (FH) of cardiovascular disease (CVD) in first degree relatives (FDR) is a major risk factor, especially for premature events. Data are sparse on FH of different manifestations of CVD among FDRs of patients with premature myocardial infarction (MI), chronic stable angina (CSA) or peripheral vascular disease (PVD).

METHODS

We obtained FHs from first degree relatives (parents or siblings) of 230 consecutive patients with premature (men < 60 and women < 65 years) CVD, including 79 wth MI, 39 CSA, 51 PVD and 61 blood donors. Among 1225 parents or siblings, 421 had MI, 222 CSA, 261PVD and 321 were among blood donors.

RESULTS

FH of MI were 5.6% (18/321) among blood donors, 14.0% (59/421) among patients with premature MI, 14.4% (32/222) CSA, and 8.0% (21/261) PVD. (all p < 0.05). For FH of CSA the corresponding frequencies were 3.7% 5.2%, 11.3%, and 6.9%. (all p < 0.05). For PVD, the corresponding frequencies were 2.1%, 3.4%, 0.9% and 0.7%, respectively. (p = ns).

CONCLUSIONS

These data are compatible with the hypothesis that FH of MI, CSA and PVD are significantly different for patients with premature MI or CSA but not PVD.

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.

Comparing the Cost Effectiveness of Non-vitamin K Antagonist Oral Anticoagulants with Well-Managed Warfarin for Stroke Prevention in Atrial Fibrillation Patients at High Risk of Bleeding

BACKGROUND

Several studies have compared the cost effectiveness of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin using results from clinical trials evaluating NOACs. However, the time in therapeutic range (TTR) of warfarin groups ranged across clinical trials, and all were below the therapeutic goal of 70%. We compared the cost effectiveness of edoxaban 60 mg, apixaban 5 mg, dabigatran 150 mg, dabigatran 110 mg, rivaroxaban 20 mg, and well-managed warfarin with a TTR of 70% in preventing stroke among patients with atrial fibrillation at high risk of bleeding.

METHODS

For the six treatments, we used a Markov state-transition model to quantify lifetime costs in $US and effectiveness in quality-adjusted life-years (QALYs). We simulated relative risk ratios of clinical events with each NOAC versus warfarin with a TTR of 70% using published regression models that predict how the incidence of thrombotic or hemorrhagic events changes for each unit change in TTR. We re-ran our analysis for two other estimates of TTR: 65 and 75%.

RESULTS

Treatment with edoxaban 60 mg cost $US127,520/QALY gained compared with warfarin with a TTR of 70% and cost $US41,860/QALY gained compared with warfarin with a TTR of 65%. However, warfarin with a TTR of 75% was more effective and less expensive than all NOACs. For three levels of TTR, apixaban 5 mg, dabigatran 150 mg, dabigatran 110 mg, and rivaroxaban 20 mg were dominated strategies.

CONCLUSIONS

The comparative cost effectiveness of edoxaban and warfarin is highly sensitive to TTR. At the $US100,000/QALY willingness-to-pay threshold, our results suggest that warfarin is the most cost-effective treatment for patients who can achieve a TTR of 70%.

The coagulation system in atherothrombosis: Implications for new therapeutic strategies

Clinical manifestations of atherosclerotic disease include coronary artery disease (CAD), peripheral artery disease (PAD), and stroke. Although the role of platelets is well established, evidence is now accumulating on the contribution of coagulation proteins to the processes of atherosclerosis and atherothrombosis. Coagulation proteins not only play a role in fibrin formation and platelet activation, but also mediate various biological and pathophysiologic processes through activation of protease-activated-receptors (PARs). Thus far, secondary prevention in patients with CAD/PAD has been the domain of antiplatelet therapy, however, residual atherothrombotic risks remain substantial. Therefore, combining antiplatelet and anticoagulant therapy has gained more attention. Recently, net clinical benefit of combining aspirin with low-dose rivaroxaban in patients with stable atherosclerotic disease has been demonstrated. In this review, based on the State of the Art lecture "Clotting factors and atherothrombosis" presented at the ISTH Congress 2017, we highlight the role of coagulation proteins in the pathophysiology of atherothrombosis, and specifically focus on therapeutic strategies to decrease atherothrombotic events by optimization of vascular protection.

Direct Oral Anticoagulants in Addition to Antiplatelet Therapy for Secondary Prevention After Acute Coronary Syndromes: A Systematic Review and Meta-analysis

Importance

Patients with acute coronary syndrome (ACS) remain at high risk for experiencing recurrent ischemic events. Direct oral anticoagulants (DOAC) have been proposed for secondary prevention after ACS.

Objective

To evaluate the safety and efficacy of DOAC in addition to antiplatelet therapy (APT) after ACS, focusing on treatment effects stratified by baseline clinical presentation (non-ST-segment elevation ACS [NSTE-ACS] vs ST-segment elevation myocardial infarction [STEMI]).

Data Sources

PubMed, Embase, BioMedCentral, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched from inception to March 1, 2017.

Study Selection

Randomized clinical trials on DOAC after ACS were evaluated for inclusion. Overall, 473 studies were screened, 19 clinical trials were assessed as potentially eligible, and 6 were included in the meta-analysis.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were used to abstract data and assess quality and validity. The risk of bias tool, version 2.0 (Cochrane) was used for risk of bias assessment. Data were pooled using random-effects models.

Main Outcomes and Measures

The prespecified primary efficacy end point was the composite of cardiovascular death, myocardial infarction, and stroke. The prespecified primary safety end point was major bleeding.

Results

Six trials that included 29 667 patients were identified (14 580 patients [49.1%] with STEMI and 15 036 [50.7%] with NSTE-ACS). The primary efficacy end point risk was significantly lower in patients who were treated with DOAC as compared with APT alone (odds ratio [OR], 0.85; 95% CI, 0.77-0.93; P < .001). This benefit was pronounced in patients with STEMI (OR, 0.76; 95% CI, 0.66-0.88; P < .001), while no significant treatment effect was observed in patients with NSTE-ACS (OR, 0.92; 95% CI, 0.78-1.09; P = .36; P for interaction = .09). With respect to safety, DOACs were associated with a higher risk of major bleeding as compared with APT alone (OR, 3.17; 95% CI, 2.27-4.42; P < .001), with consistent results in patients with STEMI (OR, 3.45; 95% CI, 1.95-6.09; P < .001) and NSTE-ACS (OR, 2.19; 95% CI, 1.38-3.48; P < .001; P for interaction = .23).

Conclusions and Relevance

To our knowledge, these findings are the first evidence to support differential treatment effects of DOAC in addition to APT according to ACS baseline clinical presentation. In patients with NSTE-ACS, the risk-benefit profile of DOAC appears unfavorable. Conversely, DOAC in addition to APT might represent an attractive option for patients with STEMI.

Non-vitamin K Antagonist Oral Anticoagulant After Acute Coronary Syndrome: Is There a Role?

Despite dual antiplatelet therapy (DAPT) including potent P2Y12 inhibitors, recurrent ischaemic events occur in a significant number of patients after acute coronary syndrome (ACS), warranting new antithrombotic strategies. Combinations of non-vitamin K antagonist oral anticoagulant (NOAC) with antiplatelet therapy have been tested in several large phases II and III randomised trials. Overall, current evidence suggests that the use of NOACs on top of DAPT after ACS reduces the rate of recurrent ischaemic events, albeit at the price of increased risk for major bleeding. In the particular field of patients with ACS and atrial fibrillation, NOACs may be associated with reduced bleeding complications compared with vitamin K antagonist. Further randomised trials evaluating low-dose NOAC combined with single antiplatelet therapy are warranted.

Progressively Worsening Premature Coronary Artery Disease: Adding Anticoagulation Stabilizes–Reverses Clinical Symptomatic Disease Progression in Thrombophilic–Atherothrombotic Patients: A Pilot Study

In 35 patients with 116 severe premature cardiovascular disease (CVD) events (median age: 48 years), 14 having worsening CVD despite maximal intervention, we evaluated thrombophilia and speculated that anticoagulation might arrest–reverse progressive thrombophilic–atherothrombotic CVD. Thrombophilia–hypofibrinolysis in the 35 patients was compared to 110 patients with venous thromboembolism (VTE) without CVD and to 110 healthy normal controls. Efficacy–safety of anticoagulation was prospectively assessed in 14 of the 35 patients whose CVD worsened over 2 years despite maximal medical–surgical intervention. At entry on maximally tolerated lipid-lowering therapy, median low-density lipoprotein was 88 mg/dL. Measures of thrombophilia–hypofibrinolysis in the 35 cases differed from 110 VTE controls only for the lupus anticoagulant, present in 6 (21%) of 28 cases versus 4 (4%) of 91 VTE controls ( P = .01), and for high anticardiolipin antibodies (ACLAs) immunoglobulin G, 5 (14%) of 35 cases versus 4 of 108 VTE controls (4%), P = .04. The 14 patients who were anticoagulated differed from 110 VTE controls only for the lupus anticoagulant, 38% versus 4%, P = .001, and for high lipoprotein (a), 46% versus 17%, P = .028, respectively. The 14 patients with atherothrombosis having inexorably worsening CAD despite maximal medical–surgical therapy were anticoagulated for 6.5 years (median), with clinical CVD progression arrested in 12 (86%), and all 12 became asymptomatic. In the 35 patients with premature CVD, thrombophilia was pervasive, comparable to or more severe than in VTE controls without CVD. When CVD progressively worsens despite maximal intervention, thrombophilia and atherosclerosis (atherothrombosis) are commonly concurrent, and the downhill course of CVD may be arrested–stabilized by anticoagulation.

The role of oral anticoagulant therapy in patients with acute coronary syndrome

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y₁₂ receptor antagonist represents the current standard of care to prevent atherothrombotic recurrences in patients with acute coronary syndrome (ACS). However, despite the use of DAPT, the recurrence rate of cardiovascular ischemic events still remains high. This persistent risk may be in part attributed to the sustained activation of the coagulation cascade leading to generation of thrombin, which may continue to play a key role in thrombus formation. The use of vitamin K antagonists (VKAs) as a strategy to reduce atherothrombotic recurrences after an ACS has been previously tested, leading to overall unfavorable outcomes due to the high risk of bleeding complications. The recent introduction of non-VKA oral anticoagulants (NOACs), characterized by a better safety profile and ease of use compared with VKA, has led to a reappraisal of the use of oral anticoagulant therapy for secondary prevention in ACS patients. The present article provides an overview of the rationale and prognostic role of oral anticoagulant therapy in ACS patients as well as recent updated clinical data, in particular with NOACs, in the field and future perspectives on this topic.

Pharmacological and Non-pharmacological Treatments for Stroke Prevention in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is associated with significant risk of stroke and other thromboembolic events, which can be effectively prevented using oral anticoagulation (OAC) with either vitamin K antagonists (VKAs) or non-VKA oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, or edoxaban. Until recently, VKAs were the only available means for OAC treatment. NOACs had similar efficacy and were safer than or as safe as warfarin with respect to reduced rates of hemorrhagic stroke or other intracranial bleeding in the respective pivotal randomized clinical trials (RCTs) of stroke prevention in non-valvular AF patients. Increasing “real-world” evidence on NOACs broadly confirms the results of the RCTs. However, individual patient characteristics including renal function, age, or prior bleeding should be taken into account when choosing the OAC with best risk–benefit profile. In patients ineligible for OACs, surgical or interventional stroke prevention strategies should be considered. In patients undergoing cardiac surgery for other reasons, the left atrial appendage excision, ligation, or amputation may be the best option. Importantly, residual stumps or insufficient ligation may result in even higher stroke risk than without intervention. Percutaneous left atrial appendage occlusion, although requiring minimally invasive access, failed to demonstrate reduced ischemic stroke events compared to warfarin. In this review article, we summarize current treatment options and discuss the strengths and major limitations of the therapies for stroke risk reduction in patients with AF.

Antiplatelet and Antithrombotic Therapy in Patients with Atrial Fibrillation Undergoing Coronary Stenting

Stroke prevention is the main priority in the management cascade of atrial fibrillation. Most patients require long-term oral anticoagulation (OAC) and may require percutaneous coronary intervention. Prevention of recurrent cardiac ischemia and stent thrombosis necessitate dual antiplatelet therapy (DAPT) for up to 12 months. Triple antithrombotic therapy with OAC plus DAPT of shortest feasible duration is warranted, followed by dual antithrombotic therapy of OAC and antiplatelet agent, and OAC alone after 12 months. Because of elevated risk of hemorrhagic complications, new-generation drug-eluting stents, lower-intensity OAC, radial access, and routine use of gastric protection with proton pump inhibitors are recommended.

An update on the pharmaceutical management of thrombosis

INTRODUCTION

Anticoagulants such as heparins and vitamin K antagonists (VKA) are effective for thrombosis prevention and treatment, but are associated with the risk of bleeding and other limitations, spurring the search for improved drugs. Areas covered: to evaluate the newer anticoagulants, focusing on those tested in phase III clinical trials such as direct oral anticoagulants (DOACs), antisense oligonucleotides (ASO) and warfarin analogues. DOACs such as dabigatran, rivaroxaban, apixaban and edoxaban are licensed for stroke prevention in atrial fibrillation and treatment of venous thromboembolism, dabigatran, rivaroxaban and apixaban for postoperative thromboprophylaxis in patients undergoing elective hip or knee arthroplasty and rivaroxaban for secondary prevention of acute coronary syndromes. ASO interfering with Factor XI hepatic synthesis were effective and safe for thromboprophylaxis in elective knee arthroplasty. Expert opinion: DOACs have overcome some limitations of anticoagulants such as VKA, but are still associated with a risk of bleeding and they lack both standardized and widely available tests measuring their anticoagulant effect and a reversal agent, except for idarucizumab, specific for dabigatran, in case of major or life threatening bleeding or emergency surgery. Agents targeting Factor XI and possibly Factor XII may be ideal anticoagulants, as they can prevent thrombosis with low bleeding risk.

Novel oral anticoagulants for acute coronary syndrome

Acute coronary syndrome (ACS) is a cardiovascular condition with a multifactorial pathophysiology that includes atherosclerotic plaques, platelet activation and thrombin production, among others. Thrombin production and the prothrombotic state of ACS patients have provided a role for anticoagulants to treat patients during the acute event and has led to subsequent research for the post-acute state. Warfarin has an indication for ACS, however, it is restricted to specific patients and many factors limit its use. Therefore, novel oral anticoagulants (NOACs) are being explored for ACS. Limitations for the use of NOACs in ACS are centered on the increased risk of bleeding that occurs when these agents are added to the current standard of care with dual antiplatelet therapy. Rivaroxaban is the only NOAC that has achieved approval in Europe for this indication with none of the NOAC currently approved in the US for use in ACS. Ongoing studies for rivaroxaban and apixaban may provide evidence to further clarify the place in therapy for NOAC agents in ACS management.