Impact of aspirin dosing on the effects of P2Y12 inhibition in patients with acute coronary syndromes

Epoxidase inhibitor-aspirin resistance and the relationship with genetic polymorphisms: a review

Strokes are the leading cause of death in most regions of the world. Epoxidase inhibitors include the drug aspirin (acetylsalicylic acid). Aspirin is widely used as first-line treatment for the prevention of cardiovascular and cerebrovascular diseases in at-risk patients. However, patients using conventional doses of aspirin can still develop ischaemic cardiovascular and cerebrovascular diseases, a phenomenon known as aspirin resistance. The occurrence of aspirin resistance hinders the prevention and treatment of ischaemic cardiovascular and cerebrovascular diseases. There are many factors affecting aspirin resistance, such as sex, drug dose, metabolic disease, genetic polymorphisms, drug interactions and pharmacokinetics. Genetic polymorphism refers to the simultaneous and frequent presence of two or more discontinuous variants or genotypes or alleles in a population of organisms. Platelets contain a large number of highly polymorphic transmembrane glycoprotein receptors encoded by two or more isomeric alleles. Changes in gene polymorphisms in various pathways during platelet aggregation can lead to aspirin resistance. This narrative review describes the gene polymorphisms that have been demonstrated to be significantly associated with aspirin resistance. Research on the mechanisms of aspirin resistance and increased knowledge should provide accurate drug guidance in individuals that require first-line antiplatelet therapy.

The Pleiotropic Role of Extracellular ATP in Myocardial Remodelling

Myocardial remodelling is a molecular, cellular, and interstitial adaptation of the heart in response to altered environmental demands. The heart undergoes reversible physiological remodelling in response to changes in mechanical loading or irreversible pathological remodelling induced by neurohumoral factors and chronic stress, leading to heart failure. Adenosine triphosphate (ATP) is one of the potent mediators in cardiovascular signalling that act on the ligand-gated (P2X) and G-protein-coupled (P2Y) purinoceptors via the autocrine or paracrine manners. These activations mediate numerous intracellular communications by modulating the production of other messengers, including calcium, growth factors, cytokines, and nitric oxide. ATP is known to play a pleiotropic role in cardiovascular pathophysiology, making it a reliable biomarker for cardiac protection. This review outlines the sources of ATP released under physiological and pathological stress and its cell-specific mechanism of action. We further highlight a series of cardiovascular cell-to-cell communications of extracellular ATP signalling cascades in cardiac remodelling, which can be seen in hypertension, ischemia/reperfusion injury, fibrosis, hypertrophy, and atrophy. Finally, we summarize current pharmacological intervention using the ATP network as a target for cardiac protection. A better understanding of ATP communication in myocardial remodelling could be worthwhile for future drug development and repurposing and the management of cardiovascular diseases.

P2Y12 blocker monotherapy after percutaneous coronary intervention

For secondary prevention of coronary artery disease (CAD) antiplatelet therapy is essential. For patients undergoing a percutaneous coronary intervention (PCI) temporary dual antiplatelet platelet therapy (DAPT: aspirin combined with a P2Y12 blocker) is mandatory, but leads to more bleeding than single antiplatelet therapy with aspirin. Therefore, to reduce bleeding after a PCI the duration of DAPT is usually kept as short as clinically acceptable; thereafter aspirin monotherapy is administered. Another option to reduce bleeding is to discontinue aspirin at the time of DAPT cessation and thereafter to administer P2Y12 blocker monotherapy. To date, five randomised trials have been published comparing DAPT with P2Y12 blocker monotherapy in 32,181 stented patients. Also two meta-analyses addressing this novel therapy have been presented. P2Y12 blocker monotherapy showed a 50-60% reduction in major bleeding when compared to DAPT without a significant increase in ischaemic outcomes, including stent thrombosis. This survey reviews the findings in the current literature concerning P2Y12 blocker monotherapy after PCI.

Pharmacokinetics and Pharmacodynamics of Approved and Investigational P2Y12 Receptor Antagonists

Coronary artery disease remains the major cause of mortality worldwide. Antiplatelet drugs such as acetylsalicylic acid and P2Y12 receptor antagonists are cornerstone treatments for the prevention of thrombotic events in patients with coronary artery disease. Clopidogrel has long been the gold standard but has major pharmacological limitations such as a slow onset and long duration of effect, as well as weak platelet inhibition with high inter-individual pharmacokinetic and pharmacodynamic variability. There has been a strong need to develop potent P2Y12 receptor antagonists with more favorable pharmacological properties. Prasugrel and ticagrelor are more potent and have a faster onset of action; however, they have shown an increased bleeding risk compared with clopidogrel. Cangrelor is highly potent and has a very rapid onset and offset of effect; however, its indication is limited to P2Y12 antagonist-naïve patients undergoing percutaneous coronary intervention. Two novel P2Y12 receptor antagonists are currently in clinical development, namely vicagrel and selatogrel. Vicagrel is an analog of clopidogrel with enhanced and more efficient formation of its active metabolite. Selatogrel is characterized by a rapid onset of action following subcutaneous administration and developed for early treatment of a suspected acute myocardial infarction. This review article describes the clinical pharmacology profile of marketed P2Y12 receptor antagonists and those under development focusing on pharmacokinetic, pharmacodynamic, and drug-drug interaction liability.

Benefit and Risks of Aspirin in Addition to Ticagrelor in Acute Coronary Syndromes: A Post Hoc Analysis of the Randomized GLOBAL LEADERS Trial

Importance

The role of aspirin as part of antiplatelet regimens in acute coronary syndromes (ACS) needs to be clarified in the context of newer potent P2Y12 antagonists.

Objective

To evaluate the benefit and risks of aspirin in addition to ticagrelor among patients with ACS beyond 1 month after percutaneous coronary intervention (PCI).

Design, Setting, and Participants

This is a nonprespecified, post hoc analysis of GLOBAL LEADERS, a randomized, open-label superiority trial comparing 2 antiplatelet treatment strategies after PCI. The trial included 130 secondary/tertiary care hospitals in different countries, with 15 991 unselected patients with stable coronary artery disease or ACS undergoing PCI. Patients had outpatient visits at 1, 3, 6, 12, 18, and 24 months after index procedure.

Interventions

The experimental group received aspirin plus ticagrelor for 1 month followed by 23-month ticagrelor monotherapy; the reference group received aspirin plus either clopidogrel (stable coronary artery disease) or ticagrelor (ACS) for 12 months, followed by 12-month aspirin monotherapy. In this analysis, we examined the clinical outcomes occurring between 31 days and 365 days after randomization, specifically in patients with ACS who, within this time frame, were assigned to receive either ticagrelor alone or ticagrelor and aspirin.

Main Outcomes and Measures

The primary outcome was the composite of all-cause death or new Q-wave myocardial infarction.

Results

Of 15 968 participants, there were 7487 patients with ACS enrolled; 3750 patients were assigned to the experimental group and 3737 patients to the reference group. Between 31 and 365 days after randomization, the primary outcome occurred in 55 patients (1.5%) in the experimental group and in 75 patients (2.0%) in the reference group (hazard ratio [HR], 0.73; 95% CI, 0.51-1.03; P = .07); investigator-reported Bleeding Academic Research Consortium-defined bleeding type 3 or 5 occurred in 28 patients (0.8%) in the experimental group and in 54 patients (1.5%) in the reference arm (HR, 0.52; 95% CI, 0.33-0.81; P = .004).

Conclusions and Relevance

Between 1 month and 12 months after PCI in ACS, aspirin was associated with increased bleeding risk and appeared not to add to the benefit of ticagrelor on ischemic events. These findings should be interpreted as exploratory and hypothesis generating; however, they pave the way for further trials evaluating aspirin-free antiplatelet strategies after PCI.

Trial Registration

ClinicalTrials.gov identifier: NCT01813435.

The association of body mass index with long-term clinical outcomes after ticagrelor monotherapy following abbreviated dual antiplatelet therapy in patients undergoing percutaneous coronary intervention: a prespecified sub-analysis of the GLOBAL LEADERS Trial

Background

The efficacy of antiplatelet therapies following percutaneous coronary intervention (PCI) may be affected by body mass index (BMI).

Methods and results

This is a prespecified subgroup analysis of the GLOBAL LEADERS trial, a prospective, multicenter, open-label, randomized controlled trial in an all-comer population undergoing PCI, comparing the experimental strategy (23-month ticagrelor monotherapy following 1-month dual antiplatelet therapy [DAPT]) with a reference regimen (12-month aspirin monotherapy following 12-month DAPT). A total of 15,968 patients were stratified by baseline BMI with prespecified threshold of 27 kg/m². Of those, 6973 (43.7%) patients with a BMI < 27 kg/m² had a higher risk of all-cause mortality at 2 years than those with BMI ≥ 27 kg/m² (adjusted HR 1.24, 95% CI 1.02–1.49). At 2 years, the rates of the primary endpoint (all-cause mortality or new Q-wave myocardial infarction) were similar between treatment strategies in either BMI group (p_interaction = 0.51). In acute coronary syndrome, however, the experimental strategy was associated with significant reduction of the primary endpoint compared to the reference strategy in patients with BMI < 27 kg/m² (HR 0.69, 95% CI 0.51–0.94), but not in the ones with BMI ≥ 27 kg/m² (p_interaction = 0.047). In chronic coronary syndrome, there was no between-group difference in the efficacy and safety of the two antiplatelet strategies.

Conclusions

Overall, BMI did not influence the treatment effect seen with ticagrelor monotherapy; however, a beneficial effect of ticagrelor monotherapy was seen in ACS patients with BMI < 27 kg/m².

Trial registration

The trial has been registered with ClinicalTrials.gov, Number NCT01813435.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01604-1) contains supplementary material, which is available to authorized users.

Antithrombotics: From Aspirin to DOACs in Coronary Artery Disease and Atrial Fibrillation (Part 3/5)

For secondary prevention of coronary artery disease (CAD), oral antiplatelet therapy is essential. In case of coronary intervention, temporary dual antiplatelet therapy is mandatory as well. Recently, low-dose oral anticoagulation has entered the CAD arena. Atrial fibrillation (AF) is often seen in CAD and vice versa. In most patients stroke prevention in AF consists of oral anticoagulation. In many cases of CAD in patients with AF, anticoagulation has to be combined with antiplatelet agents (so called, dual pathway antithrombotic therapy). Excess bleeding in these conditions is a rapidly rising problem. This review addresses the antithrombotic options in CAD alone, in AF alone, and in their combination, when either an invasive or a noninvasive approach has been chosen.

Real-world observations with prasugrel compared to clopidogrel in acute coronary syndrome patients treated with percutaneous coronary intervention in the United States

OBJECTIVES

To compare 30 and 90 day real-world acute myocardial infarction (AMI) and bleeding related rehospitalization rates in acute coronary syndrome (ACS) patients receiving percutaneous coronary intervention (PCI; ACS-PCI) treated with clopidogrel or prasugrel.

RESEARCH DESIGN AND METHODS

Using the Premier hospital database, ACS-PCI patients receiving a drug-eluting (DES) or bare-metal (BMS) stent and clopidogrel or prasugrel from July 2009 to June 2011 were analyzed. Patients were included based on the prasugrel US prescribing information (USPI), excluding patients with a history of transient ischemic attack/stroke and patients ≥75 years without diabetes or prior MI. The primary endpoint was 30 day adjusted AMI rehospitalization rate. Secondary endpoints included 90 day AMI and 30 and 90 day bleeding-related rehospitalization rates. Treatment comparisons were adjusted using propensity score stratification.

RESULTS

At the index event, prasugrel patients (N = 9404) differed from clopidogrel patients (N = 74,163) by having a lower risk of comorbid conditions associated with bleeding, being more likely younger and male, having ST-elevation MI and receiving a DES. For clopidogrel and prasugrel, respectively, the observed AMI-related rehospitalization rates were 4.7% and 3.9% at 30 days (p < 0.0001) and 6.3% and 5.1% at 90 days (p < 0.0001). After adjustment, prasugrel was associated with ∼10% lower odds of AMI-related rehospitalization (30 days: OR = 0.892 [95% CI: 0.798, 0.998]; 90 days, OR = 0.901 [95% CI: 0.817, 0.994]). Adjusted bleeding-related rehospitalization rates were similar to each other (OR = 1.035 at 30 days [95% CI: 0.765, 1.399]; OR = 0.922 at 90 days [95% CI: 0.725, 1.172]).

STUDY LIMITATIONS

Treatment adherence was not assessed. Bleeding events not resulting in a hospitalization (e.g. office, outpatient, or emergency room visits), deaths outside the hospital, or readmissions to a hospital outside of the Premier alliance were not captured in the database.

CONCLUSIONS

The different patient characteristics between prasugrel- and clopidogrel-treated patients suggest physicians are more selective in choosing patients for prasugrel than recommended in the prasugrel USPI. However, after adjustment for these differences, 30 and 90 day AMI rehospitalization rates were lower for prasugrel-treated patients compared to clopidogrel-treated patients, with no difference in adjusted bleeding-related rehospitalization rates.

Assessment of platelet function: Laboratory and point-of-care methods

In the event of blood vessel damage, human platelets are promptly recruited on the site of injury and, after their adhesion, activation and aggregation, prevent blood loss with the formation of a clot. The consequence of abnormal regulation can be either hemorrhage or the development of thrombosis. Qualitative and/or quantitative defects in platelets promote bleeding, whereas the residual reactivity of platelets, despite antiplatelet therapies, play an important role in promoting arterial thrombotic complications. Platelet function is traditionally assessed to investigate the origin of a bleeding syndrome, to predict the risk of bleeding prior surgery or during pregnancy or to monitor the efficacy of antiplatelet therapy in thrombotic syndromes that, now, can be considered a new discipline. “Old” platelet function laboratory tests such as the evaluation of bleeding time and the platelet aggregation analysis in platelet-rich plasma are traditionally utilized to aid in the diagnosis and management of patients with platelet and hemostatic disorders and used as diagnostic tools both in bleeding and thrombotic diathesis in specialized laboratories. Now, new and renewed automated systems have been introduced to provide a simple, rapid assessment of platelet function including point of care methods. These new methodologies are also suitable for being used in non-specialized laboratories and in critical area for assessing platelet function in whole blood without the requirement of sample processing. Some of these methods are also beginning to be incorporated into routine clinical use and can be utilized as not only as first panel for the diagnosis of platelet dysfunction, but also for monitoring anti-platelet therapy and to potentially assess risk of both bleeding and/or thrombosis.

Is there a need for bacterial endocarditis prophylaxis in patients undergoing gastrointestinal endoscopy?

Heart valve repair or replacement is a serious problem. Patients can benefit from an open dialogue between both cardiologists and gastroenterologists for the optimal effective patients care. The focused update on infective endocarditis of the American College of Cardiology/American Heart Association 2008 (ACC/AHA guidelines) and guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009) of the European Society of Cardiology (ESC guidelines) describe prophylaxis against infective endocarditis (IE) as not recommended for gastroscopy and colonoscopy in the absence of active infection but increasing evidence suggests that the role of IE antibiotic prophylaxis remains a dark side of the cardio-oncology prevention. New evidences concerning infective endocarditis due to Streptococcus bovis, Streptococcus agalactiae, Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, and new findings indicate that there is a need for bacterial endocarditis prophylaxis in patients undergoing gastrointestinal endoscopy especially in elderly patients and in cancer and immunocompromised patients, to avoid serious consequences.