Rivaroxaban with or without Aspirin in Stable Cardiovascular Disease

Novel aspects of antiplatelet therapy in cardiovascular disease

Antiplatelet therapy is a cornerstone in the secondary prophylaxis of adverse cardiovascular events such as myocardial infarction and stroke. The cyclooxygenase inhibitor aspirin remains the most frequently prescribed antiplatelet drug, followed by adenosine diphosphate P2Y12 receptor blockers. Glycoprotein IIb-IIIa antagonists are intravenously available antiplatelet agents preventing platelet-to-platelet aggregation via the fibrinogen receptor. The thrombin receptor inhibitor vorapaxar allows the targeting of yet a third pathway of platelet activation. Despite the advent of novel agents and major advances in antiplatelet treatment over the last decade, atherothrombotic events still impair the prognosis of many patients with cardiovascular disease. Consequently, antiplatelet therapy remains a field of intense research and a large number of studies on its various aspects are published each year. This review article summarizes recent developments in antiplatelet therapy in cardiovascular disease focusing particularly on the duration of dual antiplatelet therapy, new treatment regimens, the role of platelet function testing, and potential future targets of antiplatelet agents.

Integrating platelet and coagulation activation in fibrin clot formation

Platelets interact with the coagulation system in a multitude of ways, not only during the phases of thrombus formation, but also in specific areas within a formed thrombus. This review discusses current concepts of platelet control of thrombin generation, fibrin formation and structure, and anticoagulation. Indicated are how combined signalling via the platelet receptors for collagen (glycoprotein VI) and thrombin induces the secretion of (anti)coagulation factors, as well as surface exposure of phosphatidylserine, thereby catalysing thrombin generation. This procoagulant platelet response is also facilitated by the adhesive complexes glycoprotein Ib-V-IX and integrin αIIbβ3. In the buildup of a platelet-fibrin thrombus, the extrinsic, tissue factor-driven coagulation pathway is predominant in early stages, while the intrinsic, factor XII pathway seems to promote at later time points. Already early generation of thrombin enforces platelet responses and stimulates intra-thrombus heterogeneity with patches of loosely aggregated, contracted, and phosphatidylserine-exposing platelets. Fibrin actively formed on the surface of activated platelets supports thrombus growth, but also captures thrombin. The fibrin distribution in a thrombus appears to rely on the local procoagulant trigger and the blood flow rate. Clinical studies support the importance of the platelet-coagulation interplay, by showing beneficial effects of combination therapy in the secondary prevention of cardiovascular disease.

Cost-effectiveness of rivaroxaban and aspirin compared to aspirin alone in patients with stable cardiovascular disease: An Australian perspective

OBJECTIVE

In light of the Cardiovascular Outcomes for People using Anticoagulation Strategies (COMPASS) trial, our objective was to assess the cost-effectiveness, from the Australian healthcare perspective, of rivaroxaban in combination with aspirin versus aspirin alone for the prevention of recurrent cardiovascular disease among patients with stable atherosclerotic vascular disease.

METHODS

A Markov model was developed using input data from the COMPASS trial to predict the clinical course and costs of patients over a 20-year time-horizon. The model comprised of three health states: 'Alive without recurrent CVD', 'Alive after recurrent CVD' and 'Dead'. Costs were from the Australian public healthcare system perspective, and estimated from published sources, as were utility data. The costs of rivaroxaban were based on current acquisition prices on the Australian Pharmaceutical Benefits Schedule (PBS) and assumed as AUD$3.09/day. The main outcome of interest was the incremental cost-effectiveness ratio (ICER) in terms of cost per quality adjusted life year (QALY) gained, and cost per year of life saved (YoLS). Costs and benefits were discounted by 5.0% per year.

RESULTS

Compared to aspirin alone, rivaroxaban plus aspirin was estimated to cost an additional AUD$12,156 (discounted) per person, but lead to 0.516 YoLS (discounted) and 0.386 QALYs gained (discounted), over 20 years. These equated to ICERs of AUD$23,560/YoLS and AUD$31,436/QALY gained. We have assumed a threshold of AUD$50,000/QALY gained to signify cost-effectiveness.

CONCLUSION

Compared to aspirin, rivaroxaban in combination with aspirin is likely to be cost-effective in preventing recurrent cardiovascular events in patients with stable atherosclerotic vascular disease.

A clinical and proteomics approach to predict the presence of obstructive peripheral arterial disease: From the Catheter Sampled Blood Archive in Cardiovascular Diseases (CASABLANCA) Study

BACKGROUND

Peripheral arterial disease (PAD) is a global health problem that is frequently underdiagnosed and undertreated. Noninvasive tools to predict the presence and severity of PAD have limitations including inaccuracy, cost, or need for intravenous contrast and ionizing radiation.

HYPOTHESIS

A clinical/biomarker score may offer an attractive alternative diagnostic method for PAD.

METHODS

In a prospective cohort of 354 patients referred for diagnostic peripheral and/or coronary angiography, predictors of ≥50% stenosis in ≥1 peripheral vessel (carotid/subclavian, renal, or lower extremity arteries) were identified from >50 clinical variables and 109 biomarkers. Machine learning identified variables predictive of obstructive PAD; a score derived from the final model was developed.

RESULTS

The score consisted of 1 clinical variable (history of hypertension) and 6 biomarkers (midkine, kidney injury molecule-1, interleukin-23, follicle-stimulating hormone, angiopoietin-1, and eotaxin-1). The model had an in-sample area under the receiver operating characteristic curve of 0.85 for obstructive PAD and a cross-validated area under the curve of 0.84; higher scores were associated with greater severity of angiographic stenosis. At optimal cutoff, the score had 65% sensitivity, 88% specificity, 76% positive predictive value (PPV), and 81% negative predictive value (NPV) for obstructive PAD and performed consistently across vascular territories. Partitioning the score into 5 levels resulted in a PPV of 86% and NPV of 98% in the highest and lowest levels, respectively. Elevated score was associated with shorter time to revascularization during 4.3 years of follow-up.

CONCLUSIONS

A clinical/biomarker score demonstrates high accuracy for predicting the presence of PAD.

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.

Cardioembolic stroke: everything has changed

Historically, because of the difficulty of using warfarin safely and effectively, many patients with cardioembolic stroke who should have been anticoagulated were instead given ineffective antiplatelet therapy (or no antithrombotic therapy). With the arrival of new oral anticoagulants that are not significantly more likely than aspirin to cause severe haemorrhage, everything has changed. Because antiplatelet agents are much less effective in preventing cardioembolic stroke, it is now more prudent to anticoagulate patients in whom cardioembolic stroke is strongly suspected. Recent advances include the recognition that intermittent atrial fibrillation is better detected with more prolonged monitoring of the cardiac rhythm, and that percutaneous closure of patent foramen ovale (PFO) may reduce the risk of stroke. However, because in most patients with stroke and PFO the PFO is incidental, this should be reserved for patients in whom paradoxical embolism is likely. A high shunt grade on transcranial Doppler saline studies, and clinical clues to paradoxical embolism, can help in appropriate selection of patients for percutaneous closure. For patients with atrial fibrillation who cannot be anticoagulated, ablation of the left atrial appendage is an emerging option. It is also increasingly recognised that high levels of homocysteine, often due to undiagnosed metabolic deficiency of vitamin B12, markedly increase the risk of stroke in atrial fibrillation, and that B vitamins (folic acid and B12) do prevent stroke by lowering homocysteine. However, with regard to B12, methylcobalamin should probably be used instead of cyanocobalamin. Many important considerations for judicious application of therapies to prevent cardioembolic stroke are discussed.

Impact of polyvascular disease on patients with atrial fibrillation: Insights from ROCKET AF

BACKGROUND

We investigated the impact of polyvascular disease in patients enrolled in ROCKET AF.

METHODS

Cox regression models were used to assess clinical outcomes and treatment effects of rivaroxaban compared with warfarin in patients with atrial fibrillation and coronary, peripheral, or carotid artery disease, or any combination of the 3.

RESULTS

A total of 655 (4.6%) patients had polyvascular disease (≥2 disease locations), and 3,391 (23.8%) had single-arterial bed disease. Patients with polyvascular disease had similar rates of stroke/systemic embolism but higher rates of cardiovascular and bleeding events when compared with those without vascular disease. Use of rivaroxaban compared with warfarin was associated with higher rates of stroke in patients with polyvascular disease (hazard ratio [HR] 2.41, 95% CI 1.05-5.54); however, this was not seen in patients with single-bed (HR 0.90, 95% CI 0.64-1.28) or no vascular disease (HR 0.85, 95% CI 0.69-1.04; interaction P = .058). There was a significant interaction for major or nonmajor clinically relevant bleeding in patients with polyvascular (HR 1.23, 95% CI 0.91-1.65) and single-bed vascular disease (HR 1.30, 95% CI 1.13-1.49) treated with rivaroxaban compared with warfarin when compared with those without vascular disease (HR 0.95, 95% CI 0.87-1.04; interaction P = .0006). Additional antiplatelet therapy in this population did not improve stroke or cardiovascular outcomes.

CONCLUSION

The use of rivaroxaban compared with warfarin was associated with a higher risk of stroke and bleeding in patients with polyvascular disease enrolled in ROCKET AF. Further studies are needed to understand the optimal management of this high-risk population.

Poststatin era in atherosclerosis management: lessons from epidemiologic and genetic studies

PURPOSE OF REVIEW

Cardiovascular diseases (CVD) are the leading cause of death worldwide with over 17 million deaths every year and represent a major public health challenge. The last decade has seen the emergence of novel antiatherogenic therapies.

RECENT FINDINGS

Despite intensive lipid and blood pressure interventions, the burden of CVD is expected to markedly progress because of the global aging of the population and increasing exposure to detrimental lifestyle-related risk. Epidemiologic and genetic studies helped to better apprehend the biology of atherosclerosis and allowed pharmaceutical innovation and recent translational successes. This includes the development of novel lipid and glucose-lowering therapies and the leverage of anti-inflammatory therapies.

SUMMARY

Here, we discuss promises and expectations of emerging scientific and pharmaceutical innovations and translational successes to meet the global therapeutic demand.

Optimal pharmacological therapy in ST-elevation myocardial infarction-a review : A review of antithrombotic therapies in STEMI

Antithrombotic therapy is an essential component in the optimisation of clinical outcomes in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. There are currently several intravenous anticoagulant drugs available for primary percutaneous coronary intervention. Dual antiplatelet therapy comprising aspirin and P2Y12 inhibitor represents the cornerstone treatment for STEMI. However, these effective treatment strategies may be associated with bleeding complications. Compared with clopidogrel, prasugrel and ticagrelor are more potent and predictable, which translates into better clinical outcomes. Therefore, these agents are the first-line treatment in primary percutaneous coronary intervention. However, patients can still experience adverse ischaemic events, which might be in part attributed to alternative pathways triggering thrombosis. In this review, we provide a critical and updated review of currently available antithrombotic therapies used in patients with STEMI undergoing primary PCI. Finding a balance that minimises both thrombotic and bleeding risk is difficult, but crucial. Further randomised trials for this optimal balance are needed.

Pleiotropic effects of the hemostatic system

Atherothrombosis is characterized by the inflammatory process of atherosclerosis combined with a hypercoagulable state leading to superimposed thrombus formation. In atherosclerotic plaques, cell signaling can occur via protease-activated receptors (PARs), four of which have been identified so far (PAR1-PAR4). Proteases that are able to activate PARs can be produced systemically, but also at the sites of lesions, and they include thrombin and activated factor X. After PAR activation, downstream signaling can lead to both proinflammatory effects and a hypercoagulable state. Which specific effect occurs depends on the type of protease and activated PAR, and the site of activation. Hypercoagulable effects are mainly exerted through PAR1 and PAR4, whereas proinflammatory responses are mostly seen after PAR1 and PAR2 activation. PAR signaling pathways contribute to atherothrombosis, suggesting that inhibition of these pathways possibly prevents cardiovascular events based on this pathophysiological mechanism. In this review, we highlight the pathways by which PAR activation leads to proinflammatory responses and a hypercoagulable state. Furthermore, we give an overview of potential pharmacological treatment targets that promote vascular protection.

Targeting von Willebrand Factor in Ischaemic Stroke: Focus on Clinical Evidence

Despite great efforts in stroke research, disability and recurrence rates in ischaemic stroke remain unacceptably high. To address this issue, one potential target for novel therapeutics is the glycoprotein von Willebrand factor (vWF), which increases in thrombogenicity especially under high shear rates as it bridges between vascular sub-endothelial collagen and platelets. The rationale for vWF as a potential target in stroke comes from four bodies of evidence. (1) Animal models which recapitulate the pathogenesis of stroke and validate the concept of targeting vWF for stroke prevention and the use of the vWF cleavage enzyme ADAMTS13 in acute stroke treatment. (2) Extensive epidemiologic data establishing the prognostic role of vWF in the clinical setting showing that high vWF levels are associated with an increased risk of first stroke, stroke recurrence or stroke-associated mortality. As such, vWF levels may be a suitable marker for further risk stratification to potentially fine-tune current risk prediction models which are mainly based on clinical and imaging data. (3) Genetic studies showing an association between vWF levels and stroke risk on genomic levels. Finally, (4) studies of patients with primary disorders of excess or deficiency of function in the vWF axis (e.g. thrombotic thrombocytopenic purpura and von Willebrand disease, respectively) which demonstrate the crucial role of vWF in atherothrombosis. Therapeutic inhibition of VWF by novel agents appears particularly promising for secondary prevention of stroke recurrence in specific sub-groups of patients such as those suffering from large artery atherosclerosis, as designated according to the TOAST classification.

Prediction of Ischemic Events after Percutaneous Coronary Intervention: Thrombelastography Profiles and Factor XIIIa Activity

Background  High plasma fibrin clot strength (MA) measured by thrombelastography (TEG) is associated with increased risk of cardiac events after percutaneous coronary interventions (PCIs). Factor XIIIa (FXIIIa) cross-links soluble fibrin, shortens clot formation time (TEG-K), and increases final clot strength (MA).

Methods  We analyzed platelet-poor plasma from patients with previous PCI. Kaolin-activated TEG (R, K, MA) in citrate platelet-poor plasma and FXIIIa were measured ( n  = 257). Combined primary endpoint was defined as recurrent myocardial infarction (MI) or cardiovascular death (CVD). Relationship of FXIIIa and TEG measurements on cardiac risk was explored.

Results  FXIIIa correlated with TEG-MA ( p  = 0.002) and inversely with TEG-K ( p  < 0.001). High MA (≥35.35 mm; p  = 0.001), low K (<1.15 min; p  = 0.038), and elevated FXIIIa (≥83.51%; p  = 0.011) were associated with increased risk of CVD or MI. Inclusion of FXIIIa activity and low TEG-K in risk scores did not improve risk prediction as compared with high TEG-MA alone.

Conclusion  FXIIIa is associated with higher plasma TEG-MA and low TEG-K. High FXIIIa activity is associated with a modest increase in cardiovascular risk after PCI, but is less sensitive and specific than TEG-MA. Addition of FXIIIa does not provide additional risk stratification beyond risk associated with high fibrin clot strength phenotype measured by TEG.

Association of Diabetic Status and Glycemic Control With Ischemic and Bleeding Outcomes in Patients With Stable Coronary Artery Disease: The 5-Year CORONOR Registry

Background

The relation between diabetes mellitus, glycemic control, and ischemic and bleeding events is poorly described in outpatients with stable coronary artery disease receiving modern secondary prevention.

Methods and Results

The multicenter CORONOR (Suivi d'une cohorte de patients Coronariens stables en région Nord‐pas‐de‐Calais) registry enrolled 4184 outpatients with stable coronary artery disease, including 1297 patients (31%) with diabetes mellitus. A recent glycosylated hemoglobin (HbA1c) was available for 1146 diabetic patients, and 48% had HbA1c ≥7%. We analyzed 5‐year ischemic (cardiovascular death, myocardial infarction, and stroke) and bleeding (Bleeding Academic Research Consortium ≥3) outcomes, according to diabetic status and glycemic control. When compared with nondiabetic patients, the ischemic risk was higher in diabetic patients with HbA1c ≥7% (hazard ratio [HR], 1.57; 95% confidence interval [CI], 1.25–1.93) but not in diabetic patients with HbA1c <7% (HR, 1.06; 95% CI, 0.83–1.36). Diabetic patients with HbA1c ≥7% were at higher risk than diabetic patients with HbA1c <7% (HR, 1.47; 95% CI, 1.09–1.98). When compared with nondiabetic patients, the bleeding risk was higher in diabetic patients, with HbA1c <7% (HR, 1.66; 95% CI, 1.04–2.67) and in those with HbA1c ≥7% (HR, 1.75; 95% CI, 1.07–2.86). No difference in bleeding risk was observed between diabetic patients with HbA1c ≥7% versus those with HbA1c <7%. Similar results were obtained when adjusted for baseline characteristics.

Conclusions

The 5‐year increased risk of ischemic events in patients with stable coronary artery disease with diabetes mellitus was restricted to those with HbA1c ≥7%. By contrast, the increase in bleeding risk associated with diabetes mellitus was observed in patients with HbA1c ≥7% and in patients with HbA1c <7%. The level of HbA1c should be taken into account for future research and may help physicians to manage prolonged antithrombotic therapies in this high‐risk subgroup.

Atrial fibrillation and ischemic events with rivaroxaban in patients with stable coronary artery disease (AFIRE): Protocol for a multicenter, prospective, randomized, open-label, parallel group study

BACKGROUND

In atrial fibrillation (AF) patients with coronary artery disease (CAD), anticoagulants are commonly used in combination with antiplatelet drugs. However, dual therapy can increase the risk of bleeding, and the potential therapeutic benefits must be weighed against this. Therefore, it is recommended that dual therapy is only used for a limited time, and that monotherapy with anticoagulants should start from 1 year after percutaneous coronary intervention (PCI). However, there is a lack of evidence on the use of monotherapy, in particular with direct oral anticoagulants, in this group of patients.

METHODS

The AFIRE Study is a multicenter, prospective, randomized, open-label, parallel group study conducted in patients aged ≥20 years with non-valvular AF (NVAF) and CAD. Patients who have undergone PCI or coronary artery bypass graft at least 1 year prior to enrollment, or those without significant coronary lesions requiring PCI (≥50% stenosis), will be included. Approximately 2200 participants will be randomized to receive either rivaroxaban monotherapy or rivaroxaban plus an antiplatelet drug (aspirin, clopidogrel, or prasugrel). The primary efficacy endpoints are the composite of cardiovascular events (stroke, non-central nervous system embolism, myocardial infarction, and unstable angina pectoris requiring revascularizations) and all-cause mortality. The primary safety endpoint is major bleeding as defined by the International Society on Thrombosis and Haemostasis criteria.

CONCLUSIONS

This study will be the first to assess the efficacy and safety of rivaroxaban monotherapy in NVAF patients with stable CAD.

Efficacy and safety of adding rivaroxaban to the anti-platelet regimen in patients with coronary artery disease: a systematic review and meta-analysis of randomized controlled trials

Background

Rivaroxaban, a direct factor Xa inhibitor, has seldom been used in patients with coronary artery disease. In this analysis, we aimed to systematically compare the efficacy and safety of rivaroxaban in addition to the anti-platelet regimen in patients with coronary artery disease.

Methods

Online databases (MEDLINE, EMBASE, Cochrane database, www.ClinicalTrials.gov and Google scholar were searched for randomized controlled trials which were exclusively based on patients with coronary artery disease; and which compared efficacy (cardiovascular outcomes) and safety (bleeding outcomes) outcomes with the addition of rivaroxaban to the other anti-platelet agents. Analysis was carried out by the RevMan 5.3 software whereby odds ratios (OR) and 95% confidence intervals (CI) were generated following data input.

Results

Four trials with a total number of 40,148 patients were included (23,231 participants were treated with rivaroxaban whereas 16,919 participants were treated with placebo) in this analysis. Patients’ enrollment period varied from years 2006 to 2016. The current results showed addition of rivaroxaban to significantly lower composite endpoints (OR: 0.81, 95% CI: 0.74–0.88; P = 0.00001). In addition, all-cause death, cardiac death, myocardial infarction, and stent thrombosis were also significantly reduced (OR: 0.82, 95% CI: 0.72–0.92; P = 0.0009), (OR: 0.80, 95% CI: 0.69–0.92; P = 0.002), (OR: 0.87, 95% CI: 0.77–0.98; P = 0.03) and (OR: 0.73, 95% CI: 0.55–0.97; P = 0.03) respectively. However, stroke was not significantly different.

However, TIMI defined minor and major bleeding were significantly higher with rivaroxaban (OR: 2.27, 95% CI: 1.47–3.49; P = 0.0002) and (OR: 3.44, 95% CI: 1.13–10.52; P = 0.03) respectively. In addition, intracranial hemorrhage and bleeding which was defined according to the International Society on Thrombosis and Hemostasis criteria were also significantly higher with rivaroxaban (OR: 1.63, 95% CI: 1.04–2.56; P = 0.03) and (OR: 1.80, 95% CI: 1.45–2.22; P = 0.00001) respectively. Nevertheless, fatal bleeding was not significantly different.

Conclusions

Addition of rivaroxaban to the anti-platelet regimen was effective in patients with coronary artery disease, but the safety outcomes were doubtful. Further future trials will be able to completely solve this issue.

Rationale and design for the Vascular Outcomes study of ASA along with rivaroxaban in endovascular or surgical limb revascularization for peripheral artery disease (VOYAGER PAD)

BACKGROUND

Patients with peripheral artery disease (PAD) undergoing a lower-extremity revascularization are at heightened risk for ischemic cardiac and limb events. Although intensification of antithrombotic therapy after revascularization has demonstrated benefit in coronary disease populations, this approach has not been well studied or shown consistent benefit in PAD. Recent trial evidence demonstrated that a treatment strategy of rivaroxaban added to background antiplatelet therapy reduced ischemic risk in patients following recent acute coronary syndromes, as well as in patients with stable atherosclerotic vascular disease. Whether these benefits extend to the population of patients with symptomatic lower-extremity PAD undergoing revascularization is the objective of the VOYAGER PAD trial.

STUDY DESIGN

VOYAGER PAD is an international randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of rivaroxaban in symptomatic PAD patients undergoing a peripheral surgical and/or endovascular revascularization. Patients are randomized in a 1:1 ratio to either rivaroxaban 2.5 mg twice daily or placebo, on a background of low-dose aspirin (100 mg daily). In addition, the use of a limited course of P2Y₁₂ inhibition is allowed at the discretion of the site investigator. The primary efficacy end point is a novel composite of myocardial infarction, ischemic stroke, cardiovascular death, acute limb ischemia, and major amputation of vascular etiology. The primary safety end point is major bleeding according to the Thrombolysis in Myocardial Infarction definition. Enrolment began in August 2015 and will complete randomization of at least 6,500 patients by January 2018. This event-driven trial is expected to observe outcomes over a mean patient follow-up of 30 months.

CONCLUSIONS

VOYAGER PAD is evaluating the efficacy of rivaroxaban added to background antiplatelet therapy to reduce major cardiovascular and limb ischemic vascular outcomes in the high-risk population of PAD patients undergoing peripheral revascularization.

Updates on Prevention of Cardioembolic Strokes

Cardiac embolism continues to be a leading etiology of ischemic strokes worldwide. Although pathologies that result in cardioembolism have not changed over the past decade, there have been significant advances in the treatment and stroke prevention methods for these conditions. Atrial fibrillation remains the prototypical cause of cardioembolic strokes. The availability of new long-term monitoring devices for atrial fibrillation detection such as insertable cardiac monitors has allowed accurate detection of this leading cause of cardioembolism. The non-vitamin K antagonist oral anticoagulants have improved our ability to prevent strokes for many patients with non-valvular atrial fibrillation (NVAF). Advances in left atrial appendage closure and the U.S. Food and Drug Administration approval of the WATCHMAN (Boston Scientific) device for stroke prevention in NVAF patients who have an appropriate rationale for a nonpharmacological alternative, have revolutionized the field and provided a viable option for patients at higher hemorrhagic risk. The role of patent foramen ovale closure for secondary prevention in selected patients experiencing cryptogenic ischemic strokes at a relatively young age has become clearer thanks to the very recent publication of long-term outcomes from three major studies. Advances in the management of infective endocarditis, heart failure, valvular diseases, and coronary artery disease have significantly changed the management of such patients, but have also revealed new concerns related to assessment of ischemic versus hemorrhagic risk in the setting of antithrombotic use. The current review article aims to discuss these advances especially as they pertain to the stroke neurology practice.

Recent Advances in Primary and Secondary Prevention of Atherosclerotic Stroke

Atherosclerosis is a major cause of ischemic stroke that can be effectively prevented with appropriate lifestyle modifications and control of cardiovascular risk factors. Medical advances in recent years along with aggressive cardiovascular risk factor modifications have resulted in decreased recurrence rates of atherosclerotic stroke. Non-statin lipid-lowering molecules have recently shown clinical benefit and are recommended for very high-risk patients to reduce their risk of stroke. Aggressive hypertension treatment is crucial to reduce atherosclerotic stroke risk. Advances in antithrombotic treatments include combinations of antiplatelets and new antiplatelet agents in the acute phase post-stroke, which carries a high risk of recurrence. Intensive medical treatment has also limited the indications for carotid interventions, especially for asymptomatic disease. Intracranial atherosclerotic disease may provoke stroke through various mechanisms; it is increasingly recognized as a cause of ischemic stroke with advanced imaging and is best managed with lifestyle modifications and medical therapy. The diagnostic search for the vulnerable culprit atherosclerotic plaque is an area of intense research, from the level of the intracranial arteries to that of the aortic arch. Ultrasonography and novel magnetic resonance imaging techniques (high-resolution vessel-wall imaging) may assist in the identification of vulnerable atherosclerotic plaques as the underlying cause in cryptogenic or misdiagnosed non-atherosclerotic ischemic stroke. Vertebrobasilar atherosclerotic disease is less common than carotid artery disease; thus, high-quality data on effective prevention strategies are scarcer. However, aggressive medical treatment is also the gold standard to reduce cerebrovascular disease located in posterior circulation.

Risk of cardiovascular events and incident atrial fibrillation in patients without prior atrial fibrillation: Implications for expanding the indications for anticoagulation

BACKGROUND

There is growing interest in the role for non-vitamin K antagonist oral anticoagulants (NOACs) in patients without atrial fibrillation (AF). We aimed to provide a comprehensive assessment of the risks of ischemic stroke, myocardial infarction (MI), AF, and major bleeding in patients without previously diagnosed AF.

METHODS

Using a large US administrative database, we identified 6,495,875 patients ≥50 years between January 1, 2011, and September 30, 2016, who were not diagnosed with AF and were not treated with oral anticoagulants or nonaspirin antiplatelet agents. We assessed the risks by age, sex, the number of risk factors, and the combination of risk factors. We also calculated the number needed to treat or harm based on the untreated risks in our data set and relative risks of NOAC treatment derived from a recent clinical trial.

RESULTS

The event rates were 0.67%/y for ischemic stroke or MI, 0.96%/y for AF, and 0.52%/y for major bleeding. Among patients who had a stroke during follow-up, 84% were not diagnosed with AF at any time, and only 5% were diagnosed with AF before the stroke. Patients who had low number needed to treat for cardiovascular risk reduction (ie, potentially benefiting the most from the addition of NOACs) also had low number needed to harm for major bleeding (ie, facing serious harm).

CONCLUSIONS

Patients without diagnosed AF but with certain risk factors were at a particularly high cardiovascular risk and may require new prevention approaches. In addition to the ongoing trials, future trials in other high-risk populations, for example, diabetes and chronic kidney disease, may be warranted.

[Direct oral anticoagulants (DOACS): A necessary focus]

In 2008, we decided to enter the era of direct oral anticoagulants (DOACS). Was that the right decision to make? The answer will depend on how well we meet the conditions of proper use. This means avoiding underdosing and overdosing as well as understanding how DOACS were validated so that our prescriptions fulfill their role in the management of thrombotic disease.

Optimal duration of dual antiplatelet therapy for coronary artery disease

The optimal duration of dual antiplatelet therapy (DAPT) for stable coronary artery disease and acute coronary syndrome is a complex decision. We review current literature on standard duration DAPT versus short duration DAPT (6 months or shorter) or extended duration DAPT (>12 months) after percutaneous coronary intervention with drug-eluting stent placement, and prolonged treatment after 12 months in acute coronary syndrome. Current guideline recommendations are summarised, including the use of risk scores for ischaemic and bleeding risk assessment. Because of the limitations of current risk scores, we propose multiple patient-related and procedure-related factors for the ischaemic and bleeding risk assessment aiding in personalised DAPT duration.

Markers of Thrombin Generation Are Associated With Long-Term Clinical Outcome in Patients With ST-Segment Elevation Myocardial Infarction

Hypercoagulability in ST-segment elevation myocardial infarction (STEMI) as related to long-term clinical outcome is not clarified. We aimed to investigate whether prothrombin fragment 1+2 (F1+2), d-dimer, and endogenous thrombin potential (ETP) measured in the acute phase of STEMI were associated with outcome. Blood samples were drawn median 24 hours after symptom onset in 987 patients with STEMI. Median follow-up time was 4.6 years. Primary outcome was a composite of all-cause mortality, reinfarction, stroke, unscheduled revascularization, or rehospitalization for heart failure; secondary outcome was total mortality. The number of combined end points/total mortality was 195/79. Higher levels of d-dimer and F1+2 were observed with both end points (all P < .005), whereas ETP was significantly lower (P < .01). Dichotomized at medians, increased risk was observed for levels above median for F1+2 and d-dimer (combined end point P = .020 and P = .010 and total mortality P < .001, both), while an inverse pattern was observed for ETP (P < .02, both). Adjusting for covariates, d-dimer was still associated with reduced risk of total mortality (P = .034) and receiver operating characteristic curve analyses showed area under the curve of 0.700 (95% confidence interval, 0.640-0.758). The hypercoagulable state in acute STEMI seems to be of importance for clinical outcome.

A Case of a Reversible Neurologic Adverse Reaction to Apixaban Confirmed by Re-Challenge

Post-marketing reporting of adverse drug events is essential for new medications, as pre-FDA approval studies lack sufficient subject numbers to detect signals for rare events. Prescriptions for the novel oral anticoagulant factor Xa inhibitors (rivaroxaban, apixaban, edoxaban) have equaled or exceeded those for vitamin K antagonists in many clinical settings requiring chronic anticoagulation, and those of injectable heparins for deep vein thrombosis prophylaxis. We report the case of a 60-year-old woman followed for permanent atrial fibrillation who was prescribed apixaban. She rapidly developed worsening neurologic symptoms of imbalance and non-vertiginous dizziness preventing her from walking, headache, diplopia, and confusion/disorientation. Her symptoms began to resolve after stopping the drug, with return to baseline function within 72 h. Unbeknownst to her cardiology care team, the patient chose to re-challenge herself with apixaban at the same dose, producing identical symptoms and again total symptom resolution within 24 h of drug discontinuation. When seen by her physician, her physical examination was unchanged from her pre-treatment baseline. Symptoms did not recur when switched to rivaroxaban therapy.

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.

Anti-inflammatory agents in peripheral arterial disease

Inflammation is pivotally involved in coronary and peripheral atherosclerotic disease. This established concept is based on both experimental animal models of vascular inflammation and Mendelian randomization studies demonstrating a causal relationship between pro-inflammatory cytokines (e.g. interleukin-6) and cardiovascular disease risk. More recently, the reduction of cardiovascular events by use of an interleukin-1β inhibitor (canakinumab) has revived interest in the use of anti-inflammatory agents for the treatment of atherosclerotic disease, including peripheral arterial disease. In this mini review article we provide an update on the pleiotropic anti-inflammatory properties of approved drugs for use in cardiovascular disease (e.g. antiplatelets, statins, PCSK9 inhibitors) and discuss the role of targeted or untargeted anti-inflammatory atheroprotection in peripheral arterial disease by agents such as colchicine, methotrexate, anti-TNF-α agents and monoclonal antibodies against interleukin-signaling.

Major Adverse Limb Events and Mortality in Patients With Peripheral Artery Disease: The COMPASS Trial

BACKGROUND

Patients with lower extremity peripheral artery disease (PAD) are at increased risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). There is limited information on the prognosis of patients who experience MALE.

OBJECTIVES

Among participants with lower extremity PAD, this study investigated: 1) if hospitalizations, MACE, amputations, and deaths are higher after the first episode of MALE compared with patients with PAD who do not experience MALE; and 2) the impact of treatment with low-dose rivaroxaban and aspirin compared with aspirin alone on the incidence of MALE, peripheral vascular interventions, and all peripheral vascular outcomes over a median follow-up of 21 months.

METHODS

We analyzed outcomes in 6,391 patients with lower extremity PAD who were enrolled in the COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial. COMPASS was a randomized, double-blind placebo-controlled study of low-dose rivaroxaban and aspirin combination or rivaroxaban alone compared with aspirin alone. MALE was defined as severe limb ischemia leading to an intervention or major vascular amputation.

RESULTS

A total of 128 patients experienced an incident of MALE. After MALE, the 1-year cumulative risk of a subsequent hospitalization was 61.5%; for vascular amputations, it was 20.5%; for death, it was 8.3%; and for MACE, it was 3.7%. The MALE index event significantly increased the risk of experiencing subsequent hospitalizations (hazard ratio [HR]: 7.21; p < 0.0001), subsequent amputations (HR: 197.5; p < 0.0001), and death (HR: 3.23; p < 0.001). Compared with aspirin alone, the combination of rivaroxaban 2.5 mg twice daily and aspirin lowered the incidence of MALE by 43% (p = 0.01), total vascular amputations by 58% (p = 0.01), peripheral vascular interventions by 24% (p = 0.03), and all peripheral vascular outcomes by 24% (p = 0.02).

CONCLUSIONS

Among individuals with lower extremity PAD, the development of MALE is associated with a poor prognosis, making prevention of this condition of utmost importance. The combination of rivaroxaban 2.5 mg twice daily and aspirin significantly lowered the incidence of MALE and the related complications, and this combination should be considered as an important therapy for patients with PAD. (Cardiovascular Outcomes for People Using Anticoagulation Strategies [COMPASS]; NCT01776424).