Low-dose aspirin for primary prevention of cardiovascular events in Japanese patients 60 years or older with atherosclerotic risk factors: a randomized clinical trial

Aspirin resistance and other aspirin-related concerns

Aspirin is a widely used medication and has become a cornerstone for treating cardiovascular disease. Aspirin can significantly reduce the incidence of cardiovascular ischemic events, recurrence and mortality, thereby improving the long-term prognosis of patients. However, there has been a staggering increase in the volume of literature addressing the issue of so-called "aspirin resistance" in recent years, and for some patients, it is difficult to avoid adverse reactions to aspirin. In this review, we present both the historical aspects of aspirin use and contemporary developments in its clinical use.

Immune-mediated and lipid-mediated platelet function in atherosclerosis

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is the leading cause of death and morbidity worldwide. Detailed knowledge of the mechanisms of atherosclerosis, the main underlying disease of CVD, will enable improved preventive and therapeutic options, thus potentially limiting the burden of vascular disease in aging societies. A large body of evidence illustrates the contribution of platelets to processes beyond their traditionally recognized role as mediators in thrombosis and hemostasis. Recent advances in molecular biology help to understand the complexity of atherosclerosis.

RECENT FINDINGS

This article outlines the role of platelets as modulators of immune responses in the context of atherosclerosis. It provides a short overview of interactions between platelets and endothelial cells or immune cells via direct cell contact or soluble factors during atherogenesis. By means of some well examined, exemplary pathways (e.g. CD40/CD40L dyad), this article will discuss recent discoveries in immune-related function of platelets. We also focus on the relationship between platelets and the lipid metabolism highlighting potential consequences to atherosclerosis and dyslipidemia.

SUMMARY

A better understanding of the molecular mechanisms of platelet-related immune activity allows their utilization as powerful diagnostic tools or targets of therapeutic intervention. Those findings might help to develop new classes of drugs which may supplement or replace classical anticoagulants and help clinicians to tackle CVD more efficiently.

Chemoprevention of cancer: current evidence and future prospects

Cancer chemoprevention refers to the use of agents for the inhibition, delay, or reversal of carcinogenesis before invasion. In the present review, agents examined in the context of cancer chemoprevention are classified in four major categories—hormonal, medications, diet-related agents, and vaccines—and the main representatives of each category are presented. Although there are serious constraints in the documentation of effectiveness of chemopreventive agents, mainly stemming from the long latency of the condition they are addressing and the frequent lack of intermediate biomarkers, there is little disagreement about the role of aspirin, whereas a diet rich in vegetables and fruits appears to convey more protection than individual micronutrients. Among categories of cancer chemopreventive agents, hormonal ones and vaccines might hold more promise for the future. Also, the identification of individuals who would benefit most from chemopreventive interventions on the basis of their genetic profiles could open new prospects for cancer chemoprevention.

Preventing cardiovascular disease in patients with diabetes: use of aspirin for primary prevention

Diabetics are at high risk for atherosclerotic cardiovascular disease (ASCVD) and are considered a coronary heart disease risk equivalent. The utility of aspirin in primary prevention of ASCVD in diabetic patients has been widely studied and is still debated. Overall, the current evidence suggests a modest benefit for reduction in ASCVD events with the greatest benefit among those with higher baseline risk, but at the cost of increased risk of gastrointestinal bleeding. Diabetic patients at higher risk (with 10-year ASCVD risk >10 %) are generally recommended for aspirin therapy if bleeding risk is felt to be low. A patient-provider discussion is recommended before prescribing aspirin therapy. Novel markers such as coronary artery calcium scores and high-sensitivity C-reactive protein may help refine ASCVD risk prediction and guide utility for aspirin therapy. This article will review the literature for the most up-to-date studies evaluating aspirin therapy for primary prevention of ASCVD in patients with diabetes.

The Japan Statin Treatment Against Recurrent Stroke (J-STARS): A Multicenter, Randomized, Open-label, Parallel-group Study

BACKGROUND

Although statin therapy is beneficial for the prevention of initial stroke, the benefit for recurrent stroke and its subtypes remains to be determined in Asian, in whom stroke profiles are different from Caucasian. This study examined whether treatment with low-dose pravastatin prevents stroke recurrence in ischemic stroke patients.

METHODS

This is a multicenter, randomized, open-label, blinded-endpoint, parallel-group study of patients who experienced non-cardioembolic ischemic stroke. All patients had a total cholesterol level between 4.65 and 6.21 mmol/L at enrollment, without the use of statins. The pravastatin group patients received 10 mg of pravastatin/day; the control group patients received no statins. The primary endpoint was the occurrence of stroke and transient ischemic attack (TIA), with the onset of each stroke subtype set to be one of the secondary endpoints.

FINDING

Although 3000 patients were targeted, 1578 patients (491 female, age 66.2 years) were recruited and randomly assigned to pravastatin group or control group. During the follow-up of 4.9 ± 1.4 years, although total stroke and TIA similarly occurred in both groups (2.56 vs. 2.65%/year), onset of atherothrombotic infarction was less frequent in pravastatin group (0.21 vs. 0.64%/year, p = 0.0047, adjusted hazard ratio 0.33 [95%CI 0.15 to 0.74]). No significant intergroup difference was found for the onset of other stroke subtypes, and for the occurrence of adverse events.

INTERPRETATION

Although whether low-dose pravastatin prevents recurrence of total stroke or TIA still needs to be examined in Asian, this study has generated a hypothesis that it may reduce occurrence of stroke due to larger artery atherosclerosis.

FUNDING

This study was initially supported by a grant from the Ministry of Health, Labour and Welfare, Japan. After the governmental support expired, it was conducted in collaboration between Hiroshima University and the Foundation for Biomedical Research and Innovation.

Are the current recommendations for the use of aspirin in primary prevention of cardiovascular disease applicable in low-income countries?

Although evidence has accumulated that long-term aspirin therapy is beneficial in secondary prevention of cardiovascular disease (CVD), a lot of controversies persist regarding the benefit of aspirin use in primary prevention of CVD. In low-income countries (LIC) specifically, the decision to prescribe aspirin for primary CVD prevention is more problematic, as there is a dearth of evidence in this regard. Aspirin has been shown to have relative beneficial effects in preventing a first myocardial infarction, but not stroke. However, as stroke is the prevailing CVD in many LIC, especially in Africa, the benefit of aspirin in these settings is therefore questionable. Indeed, there is no published trial that has evaluated the benefits and risks of continuous aspirin therapy in populations of LIC. Furthermore, though cardiovascular risk assessment is crucial in decision-making for the use of aspirin in primary prevention of CVD, there are no risk assessment tools that have been validated in African populations. Studies are urgently warranted, to determine the usefulness of aspirin in primary prevention of CVD in low-income settings where the drug is highly available and affordable, as CVD is becoming the leading cause of deaths in LIC.

What's new in stroke? Phase III randomized clinical trials of 2012-2014

BACKGROUND

Randomized clinical trials provide the most reliable evidence to guide the management of stroke and threatened stroke and reflect the interests of the stroke research community. The spectrum of phase III randomized clinical trials in stroke has not been previously characterized.

METHODS

Phase III stroke randomized clinical trials published between 2012 and 2014 were identified by search of the Cochrane Central Register of Controlled Trials supplemented by recent publications known to the co-authors.

RESULTS

Thirty-four randomized clinical trials were included involving 85 770 participants: 20 acute stroke randomized clinical trials (32 590 patients), 11 stroke prevention randomized clinical trials (28 964 patients), and three randomized clinical trials in which stroke was a major component of a composite primary outcome involving nonstroke patients (24 216 patients). Twenty-two (65%) trials were international, and eight (24%) were industry sponsored. Drugs were tested in 21 (62%) randomized clinical trials, with devices (n = 9), surgery (n = 3), and diet (n = 1) in the remainder. Thirteen (38%) randomized clinical trials were stopped early: seven for futility, three for efficacy, two for harm, and one for budget/administrative reasons. Overall, the results of seven (21%) randomized clinical trials were positive, five (15%) equivocal, 18 (53%) negative, and four (12%) inconclusive. Considering positive and definitively negative randomized clinical trials testing currently used interventions, 11 (32%) randomized clinical trials have direct implications for clinical management.

CONCLUSIONS

The diversity of interventions, high-quality, and worldwide origins of recently published phase III randomized clinical trials reflects a vibrant international stroke research community. The current generation of stroke randomized clinical trials provides important guidance for stroke prevention and acute stroke care.

Antidiabetic and cardiovascular drug utilisation in patients diagnosed with type 2 diabetes mellitus over the age of 80 years: a population-based cohort study

BACKGROUND

there is a lack of evidence to inform treatment recommendations for very old people with type 2 diabetes mellitus (T2DM).

OBJECTIVE

to evaluate trends in antidiabetic and cardiovascular drug utilisation for patients developing T2DM over 80 years of age.

METHODS

a population-based cohort was sampled from the UK Clinical Practice Research Datalink between 1990 and 2013. Eligible patients were those with T2DM diagnosed after the age of 80 years and prescribed antidiabetic drugs.

RESULTS

twelve thousand eight hundred and eighty-one patients, with 61% of females, were included. From 1990 to 2013, use of sulphonylureas declined from 94 to 29%, while metformin use increased from 22 to 86%. Prescribing of antihypertensive drugs increased substantially from 46 to 77%, lipid-lowering drugs from 1 to 64%, antiplatelets from 34 to 47% and oral anticoagulants from 5 to 19%. Women were more frequently prescribed antihypertensive drugs (odds ratio 1.26, 95% confidence interval 1.17 to 1.37) but less prescribed antiplatelets (0.83, 0.78 to 0.89). Compared with those diagnosed with T2DM from 80 to 89 years (n = 11,467, 89%), patients diagnosed after the age of 90 years (n = 1,414, 11%) were less likely to be prescribed insulin (0.37, 0.24 to 0.58), metformin (0.67, 0.60 to 0.75), antihypertensive drugs (0.42, 0.38 to 0.48), lipid-lowering drugs (0.26, 0.23 to 0.30) and anticoagulants (0.55, 0.44 to 0.68).

CONCLUSIONS

there have been major increases in the intensity of pharmacological management of patients diagnosed with T2DM over 80 years of age, but the effectiveness and safety of these interventions in very old people require further evaluation.

High-risk type-2 diabetes mellitus patients, without prior ischemic events, have normal blood platelet functionality profiles: a cross-sectional study

Background

Patients with type 2 diabetes mellitus (DM) display a predisposition for vascular disease. Platelets taken from vasculopathic diabetic patients, show enhanced stimuli-induced activation and aggregation responses. Aspirin remains the cornerstone antiplatelet agent for secondary prevention of vascular complications among diabetic patients, yet evidence of its efficacy and safety in primary prevention are conflicting. Our aim was to assess whether high risk diabetic patients, without previous ischemic events, have abnormal platelet functionality profiles.

Methods

The study included 82 diabetic patients and 86 matched non-diabetic patients without prior ischemic events nor treatment with anti-platelet medications. Blood samples were analyzed for platelet markers of activation, turnover and leukocyte-platelet interactions.

Results

Our final analysis included 122 males (74 %), with a mean age of 61 years. Mean platelet volume (MPV) was similar between the diabetic patients and controls (9.2 fL for both). Following activation, PAC-1 binding and P-selectin expression were found comparable between the diabetic patients and controls (83 % versus 81 % and 76 % versus 74 %, respectively). Leukocyte-platelet aggregates (LPAs) were similar between the diabetic patients and controls (18 % versus 17 %, respectively). Neutrophil-platelet aggregates (NPAs) and monocyte-platelet aggregates (MPAs) were also found similar in the diabetic patients and controls. Elevated fasting plasma glucose was associated with increased LPAs rates.

Conclusions

High risk type-2 diabetes mellitus patients, without prior ischemic events, have normal blood platelet functionality profiles.

Association between Aspirin Therapy and Clinical Outcomes in Patients with Non-Obstructive Coronary Artery Disease: A Cohort Study

Background

Presence of non-obstructive coronary artery disease (CAD) is associated with increased prescription of cardiovascular preventive medications including aspirin. However, the association between aspirin therapy with all-cause mortality and coronary revascularization in this population has not been investigated.

Methods and Findings

Among the cohort of individuals who underwent coronary computed tomography angiography (CCTA) from 2007 to 2011, 8372 consecutive patients with non-obstructive CAD (1-49% stenosis) were identified. Patients with statin or aspirin prescription before CCTA, and those with history of revascularization before CCTA were excluded. We analyzed the differences of all-cause mortality and a composite of mortality and late coronary revascularization (>90 days after CCTA) between aspirin users (n=3751; 44.8%) and non-users. During a median of 828 (interquartile range 385–1,342) days of follow-up, 221 (2.6%) mortality cases and 295 (3.5%) cases of composite endpoint were observed. Annualized mortality rates were 0.97% in aspirin users versus 1.28% in non-users, and annualized rates of composite endpoint were 1.56% versus 1.48%, respectively. Aspirin therapy was associated with significantly lower risk of all-cause mortality (adjusted HR 0.649; 95% CI 0.492–0.857; p=0.0023), but not with the composite endpoint (adjusted HR 0.841; 95% CI 0.662–1.069; p=0.1577). Association between aspirin and lower all-cause mortality was limited to patients with age ≥65 years, diabetes, hypertension, decreased renal function, and higher levels of coronary artery calcium score, low-density lipoprotein cholesterol and high-sensitivity C-reactive protein.

Conclusions

Among the patients with non-obstructive CAD documented by CCTA, aspirin is associated with lower all-cause mortality only in those with higher risk.

Statins and aspirin: do they really work in women?

Cardiovascular disease continues to be the most common cause of mortality in women in the USA. As a result, greater emphasis has been placed on preventive measures. Studies examining the role of aspirin and HMG-CoA reductase inhibitors (statins) have shown important clinical differences in men versus women in the preventive realm. This has led to inconsistent recommendations by guideline committees and clinicians alike. This review presents a summary of the past and current guidelines. In addition, important clinical trials influencing current era practice are also discussed. Both strengths and limitations of these studies are described in detail, along with recommendations regarding future directions and the scope of aspirin and statin use for primary and secondary prevention of cardiovascular disease.

Platelets in inflammation and atherogenesis

Platelets contribute to processes beyond thrombus formation and may play a so far underestimated role as an immune cell in various circumstances. This review outlines immune functions of platelets in host defense, but also how they may contribute to mechanisms of infectious diseases. A particular emphasis is placed on the interaction of platelets with other immune cells. Furthermore, this article outlines the features of atherosclerosis as an inflammatory vascular disease highlighting the role of platelet crosstalk with cellular and soluble factors involved in atheroprogression. Understanding, how platelets influence these processes of vascular remodeling will shed light on their role for tissue homeostasis beyond intravascular thrombosis. Finally, translational implications of platelet-mediated inflammation in atherosclerosis are discussed.

Aspirin underuse, non-compliance or cessation: definition, extent, impact and potential solutions in the primary and secondary prevention of cardiovascular disease

Despite momentous breakthroughs in unraveling the pathophysiology of many chronic conditions and developing novel therapeutic agents, everyday clinical practice is still fraught with inadequate or inappropriate use of treatments with proven benefits. Aspirin is a paradigmatic example, as it is used for the primary and secondary prevention of cardiovascular disease and appears to have a beneficial impact on cancer risk. Yet, underuse, non-compliance or cessation of aspirin are not uncommon, may have an important clinical impact, and are not aggressively prevented or managed. Increasing the awareness of the extent and impact of aspirin underuse, non-compliance or cessation, and intensifying efforts at preventing them are worthy goals likely to yield significant benefits on cardiovascular morbidity and mortality worldwide, and possibly also on cancer outcomes.

Current antiplatelet agents: place in therapy and role of genetic testing

Antiplatelet therapies play a central role in reducing the risk of cardiovascular events such as myocardial infarction and stroke. While aspirin, a cyclo-oxygenase-1 inhibitor has been the cornerstone of antithrombotic treatment for several decades, P2Y12 receptor inhibitors cangrelor, clopidogrel, prasugrel, and ticagrelor and protease-activated receptor-1 antagonist vorapaxar, have emerged as additional therapies to reduce the risk of recurrent cardiovascular events in high-risk patients. Recent clinical trials evaluating the role of these agents and major society guideline updates for use of antiplatelet therapies for secondary prevention of cardiovascular events will be examined. The latest studies regarding the appropriate duration of dual antiplatelet therapy after percutaneous coronary intervention will be presented. The current state of genetic and platelet function testing will be reviewed.

Report of the American Heart Association (AHA) Scientific Sessions 2014, Chicago

The American Heart Association (AHA) Scientific Sessions were held in Chicago on November 15-19, 2014. The meeting attracted more than 17,000 participants, including physicians, research scientists, students, and paramedical personnel, from more than 100 countries. Sessions over the 5 days included comprehensive and unparalleled education delivered via more than 5,000 presentations, with 1,000 invited faculty members and 4,000 abstract presentations from world leaders in cardiovascular (CV) disease. There were 16 trials scheduled in 4 late-breaking clinical trial sessions. The Dual Antiplatelet Therapy study revealed that aspirin plus a thienopyridine beyond 1 year subsequent to placement of a drug-eluting stent, as compared with aspirin therapy alone, significantly reduced stent thrombosis and major CV and cerebrovascular events but was associated with increased risk of bleeding. The IMPROVE-IT research showed that, relative to simvastatin with placebo, simvastatin with 10 mg of ezetimibe daily led to a significantly lower primary combined endpoint in moderate- to high-risk patients, who stabilized following acute coronary syndrome. This was the first trial to demonstrate incremental clinical benefit by adding a nonstatin agent to statin therapy and reaffirmed the low-density lipoprotein (LDL) hypothesis stating that reducing LDL-cholesterol prevents CV events. Summaries and overviews of both the late-breaking trials and the sessions to which members of the Japanese Circulation Society contributed are presented.