The physicians' health study: aspirin for the primary prevention of myocardial infarction

A Thorough Literature Review of the Potential Benefits and Drawbacks of Long-Term Aspirin Use for the Primary Prevention of Cardiovascular Disease

This article examines the role of aspirin in the primary prevention of cardiovascular disease. It highlights findings from major studies such as ASPREE (ASPirin in Reducing Events in the Elderly), ARRIVE (Aspirin to Reduce Risk of Initial Vascular Events), and ASPREE-XT (ASPirin in Reducing Events in the Elderly - eXTension) , among others. The review focuses on aspirin's role in primary prevention for specific populations including older adults, diabetics, hypertension patients, rheumatoid arthritis patients, kidney transplant recipients, and those with specific lipoprotein(a) genotypes, among other groups. We review these studies, noting aspirin's role in reducing events such as myocardial infarctions and its potential for increasing bleeding risks. The review also considers the implications for patients with kidney disease, referencing the Chronic Renal Insufficiency Cohort (CRIC) study and the International Polycap Study-3 (TIPS-3) trial. Additionally, it addresses the shifting paradigms in guidelines from the US Preventive Services Task Force and other entities, underscoring the importance of individualized aspirin use by balancing benefits against bleeding risks. The article further explores the concept of platelet reactivity, discusses strategies for improving adherence to aspirin therapy, and identifies existing research gaps, such as the phenomenon of aspirin resistance. It concludes by suggesting potential areas for future investigation to enhance understanding and application of aspirin in cardiovascular disease prevention.

Perspectives from a Pathologist: My Journey on the Path to Women's Health Research, Sex and Gender Policy, and Practice Implications

These words reflect my recollections of major transition points in my life and career: as I first became dedicated to becoming a physician, being introduced to the field of pathology and research, and then transitioning to a somewhat different career focus by becoming the first director of the National Institutes of Health Office of Research on Women's Health. Many of the experiences that I gained during my years in pathology served me well as I made efforts to establish women's health research and sex and gender based studies as scientific endeavors. Participating in research and teaching as an academic pathologist, setting funding priorities, and supporting and encouraging research careers through governmental office programs have been the essence of my more than 50 years as a pathologist and physician.

Platelets and Cardiovascular Disease

Platelets play an important, but often under-recognized role in cardiovascular disease. For example, the normal response of the platelet can be altered, either by increased pro-aggregatory stimuli or by diminished anti-aggregatory substances to produce conditions of increased platelet activation/aggregation and occur in active cardiovascular disease states both on a chronic (e.g. stable angina pectoris) and acute basis (e.g. acute myocardial infarction). In addition, platelet hyperaggregability is also associated with the risk factors for coronary artery disease (e.g. smoking, hypertension, and hypercholesterolaemia). Finally, the utility of an increasing range of anti-platelet therapies in the management of the above disease states further emphasizes the pivotal role platelets play in the pathogenesis of cardiovascular disease. This paper provides a comprehensive overview of the normal physiologic role of platelets in maintain homeostasis, the pathophysiologic processes that contribute to platelet dysfunction in cardiovascular disease and the associated role and benefits of anti-platelet therapies.

Sex and the Lab: An Alcohol-Focused Commentary on the NIH Initiative to Balance Sex in Cell and Animal Studies

In May 2014, Dr. Francis Collins, the director of U.S. National Institutes of Health (NIH), and Dr. Janine Clayton, the director of the U.S. National Institutes of Health Office of Research on Women's Health, published a commentary in the journal Nature announcing new policies to ensure that preclinical research funded by the NIH considers both males and females. While these policies are still developing, they have already generated great interest by the scientific community and triggered both criticism and applause. This review provides a description and interpretation of the NIH guidelines, and it traces the history that led to their implementation. As expected, this NIH initiative generated some anxiety in the scientific community. The use of female animals in the investigation of basic mechanisms is perceived to increase variability in the results, and the use of both sexes has been claimed to slow the pace of scientific discoveries and to increase the cost at a time characterized by declining research support. This review discusses issues related to the study of sex as a biological variable (SABV) in alcohol studies and provides examples of how researchers have successfully addressed some of them. A practical strategy is provided to include both sexes in biomedical research while maintaining control of the research direction. The inclusion of sex as an important biological variable in experimental design, analysis, and reporting of preclinical alcohol research is likely to lead to a better understanding of alcohol pharmacology and the development of alcohol use disorder, may promote drug discovery for new pharmacotherapies by increasing scientific rigor, and may provide clinical benefit to women's health. This review aims to promote the understanding of the NIH's SABV guidelines and to provide alcohol researchers with a theoretical and practical framework for working with both sexes in preclinical research.

Clinical use of aspirin in treatment and prevention of cardiovascular disease

Cardiovascular disease (CVD), principally heart disease and stroke, is the leading cause of death for both males and females in developed countries. Aspirin is the most widely used and tested antiplatelet drug in CVD, and it is proven to be the cornerstone of antiplatelet therapy in treatment and prevention of CVD in clinical trials in various populations. In acute coronary syndrome, thrombotic stroke, and Kawasaki's disease, acute use of aspirin can decrease mortality and recurrence of cardiovascular events. As secondary prevention, aspirin is believed to be effective in acute coronary syndrome, stable angina, revascularization, stroke, TIA, and atrial fibrillation. Aspirin may also be used for patients with a high risk of future CVD for primary prevention, but the balance between benefits and the possibility of side effects must be considered.

Limitations of current therapies to prevent thrombosis: a need for novel strategies

Bleeding limits the benefit of current anti-platelet drugs for preventing heart attacks and stroke. Aspirin and clopidogrel, the two most widely prescribed anti-platelet drugs, are metabolized to active compounds that covalently and irreversibly modify their respective therapeutic targets (COX1 and P2Y12). The enduring effects of aspirin and clopidogrel are of concern in patients receiving anti-platelet therapy who require emergency surgery as this places them at greater risk of haemorrhage. As clopidogrel must be activated by cytochrome P450 metabolism, recent pharmacogenomic studies have revealed that patients lacking a functional allele of CYP2C19 derive no therapeutic benefit from the drug. Prasugrel, a second generation thienopyridine, whose bioconversion is not affected by CYP genetic polymorphism, demonstrates improved clinical benefit, but with increased bleeding risk. Anti-platelet drugs currently in cardiovascular trials that may have reduced bleeding risk include reversible P2Y12 antagonists (cangrelor, ticagrelor, and elinogrel), a PAR1 antagonist (SCH 530 348) and an EP3 antagonist (DG-041). The platelet EP3 receptor for prostaglandin E(2) is an attractive therapeutic target as EP3 antagonists may selectively avert thrombosis over atherosclerotic plaques without affecting bleeding risk.

Antagonists of the EP3 receptor for prostaglandin E2 are novel antiplatelet agents that do not prolong bleeding

Myocardial infarction and stroke are caused by blood clots forming over a ruptured or denuded atherosclerotic plaque (atherothrombosis). Production of prostaglandin E(2) (PGE(2)) by an inflamed plaque exacerbates atherothrombosis and may limit the effectiveness of current therapeutics. Platelets express multiple G-protein coupled receptors, including receptors for ADP and PGE(2). ADP can mobilize Ca(2+) and through the P(2)Y(12) receptor can inhibit cAMP production, causing platelet activation and aggregation. Clopidogrel (Plavix), a selective P(2)Y(12) antagonist, prevents platelets from clotting but thereby increases the risk of severe or fatal bleeding. The platelet EP(3) receptor for PGE(2), like the P(2)Y(12) receptor, also inhibits cAMP synthesis. However, unlike ADP, facilitation of platelet aggregation via the PGE(2)/EP(3) pathway is dependent on co-agonists that can mobilize Ca(2+). We used a ligand-based design strategy to develop peri-substituted bicylic acylsulfonamides as potent and selective EP(3) antagonists. We show that DG-041, a selective EP(3) antagonist, inhibits PGE(2) facilitation of platelet aggregation in vitro and ex vivo. PGE(2) can resensitize platelets to agonist even when the P(2)Y(12) receptor has been blocked by clopidogrel, and this can be inhibited by DG-041. Unlike clopidogrel, DG-041 does not affect bleeding time in rats, nor is bleeding time further increased when DG-041 is co-administered with clopidogrel. This indicates that EP(3) antagonists potentially have a superior safety profile compared to P(2)Y(12) antagonists and represent a novel class of antiplatelet agents.

Safety profile of rofecoxib as used in general practice in England: results of a prescription-event monitoring study

AIMS

A postmarketing Prescription-Event Monitoring study was undertaken to monitor the safety of rofecoxib, a cyclo-oxygenase (COX)-2 selective inhibitor prescribed in primary care in England.

METHODS

Questionnaires requesting clinical event data were sent to prescribing physicians between February and November 2000, and the data analysed for all events.

RESULTS

There were 15,268 patients identified, mean age 62 years, 67% female. The commonest specified indication was osteoarthritis (24%). Dyspepsia and nausea were the most frequently reported adverse events. A history of dyspeptic or upper gastrointestinal (GI) conditions, recent use of other nonsteroidal anti-inflammatory drugs (NSAIDs), use of selected concomitant gastroirritant drugs (NSAIDs, aspirin, anticoagulants, antiplatelet drugs), or gastroprotective drugs (misoprostol, antacids, proton-pump inhibitors, histamine-2 antagonists), and age (>/= 65 years) modified the risk of having minor GI events. During treatment or within 1 month of stopping, 110 serious GI events were reported (including 76 upper GI bleeds/peptic ulcers, one perforated colon), 101 thromboembolic events, three reports of acute renal failure, one each of Stevens-Johnson syndrome, severe anaphylaxis and angio-oedema.

CONCLUSIONS

Doctors should continue to prescribe NSAIDs including COX-2 selective inhibitors with caution.

Aspirin in the prophylaxis of coronary artery disease

Aspirin has been used for more than 100 years, but its mechanisms of action have only been understood in the past 20 years. Aspirin interferes with arachidonic acid metabolism in platelets and endothelial cells and thereby reduces thromboxane A2 and prostacyclin. It also has other mechanisms of action, including anti-inflammatory roles, protection from oxidative stress, enhancement of fibrinolysis, and suppression of plasma coagulation and platelet-dependent inhibition of thrombin generation. It has been used for primary and secondary prevention of myocardial ischemia, and for primary and secondary prevention of cerebrovascular ischemia. We review the 5 pivotal studies relating to primary prevention for cardiovascular risk and the many studies relating to secondary prevention of myocardial ischemia. We also review the utility of aspirin in primary prevention of myocardial infarction and stroke. We conclude that aspirin is one of the most potent drugs ever discovered and that its effects extend well beyond those of cycloxoxygenase enzyme inhibition. Aspirin treatment does not preclude control of underlying and comorbid conditions such as diabetes mellitus, hypertension, and dyslipidemia. For most patients, a daily dose of 325 mg is optimal. Patients must understand the potential for gastrointestinal upset and hemorrhagic complications. The utility of aspirin is greater in coronary artery disease prevention than in cerebrovascular prevention.

Correlation between template bleeding times and spontaneous bleeding during treatment of acute myocardial infarction with recombinant tissue-type plasminogen activator

The purpose of this study was to correlate bleeding complications during and after treatment with recombinant tissue-type plasminogen activator (rt-PA) with serial template bleeding time measurements, with ADP-induced platelet aggregation, with clinical characteristics, and with hemostatic parameters. Fifty-two of 55 consecutive patients with acute myocardial infarction and template bleeding times (Ivy method) of less than 9.5 minutes were treated with rt-PA in a total dose of 55-212 mg (mean, 109 mg) over 90 to 360 minutes (median, 240 minutes) combined with heparin. The mean bleeding time was significantly prolonged at 90 minutes (from 5.0 +/- 1.9 to 8.2 +/- 4.3 minutes, p less than 0.0001) but returned toward baseline after 4 hours (from a median of 8.0 to 7.0 minutes, p less than 0.05). Thirteen patients (25%) suffered relatively minor but spontaneous bleeding that did not correlate with age, hypertension, smoking, partial thromboplastin time, platelet count, ADP-induced platelet aggregation, steady-state rt-PA level, or extent of fibrinogen degradation. In multivariate analysis, only the 90-minute bleeding time correlated with spontaneous bleeding (p = 0.01). Prolongation of the 90-minute bleeding time to greater than or equal to 9 minutes, which occurred in 21 patients, correlated with spontaneous bleeding with a sensitivity of 69% (95% confidence interval, 39-90%) and a specificity of 69% (95% confidence interval, 52-83%). Retrospective analysis revealed that in 14 patients taking aspirin, the bleeding time at 90 minutes was significantly more prolonged (p less than 0.05) and spontaneous bleeding significantly more frequent (p less than 0.01) than in patients not taking aspirin.(ABSTRACT TRUNCATED AT 250 WORDS)