Evaluating current and emerging antithrombotic therapy currently available for the treatment of acute coronary syndrome in geriatric populations

Outcomes of Nonagenarians With Acute Coronary Syndrome

OBJECTIVES

Nonagenarians are a fast-growing age group among cardiovascular patients, but data about their management and prognosis after an acute coronary syndrome (ACS) is scarce. This study aimed to analyze characteristics of nonagenarian patients with ACS and to compare in-hospital and 1-year clinical outcomes between those treated with medical treatment (MT) alone and those receiving percutaneous coronary intervention (PCI).

DESIGN

Multicenter observational study.

SETTING AND PARTICIPANTS

We included consecutive nonagenarian patients with ACS admitted at 4 academic centers between 2005 and 2018. Only patients with type 1 myocardial infarction were included.

METHODS

Standardized definitions of all patient-related variables, clinical diagnoses, and hospital complications and outcomes were used. The primary endpoint was 1-year all-cause mortality. Long-term survival was compared between patients undergoing PCI and those managed with MT alone. Given differences in baseline characteristics could substantially interfere in outcomes, 3 sensitivity analyses were performed to adjust for confounders.

RESULTS

A total of 680 nonagenarians were included (59% females). Of them, 373 (55%) patients presented with non-ST-segment elevation ACS (NSTE-ACS) and 307 (45%) with ST-segment elevation myocardial infarction (STEMI). A coronary angiogram was performed in 115 (31%) of NSTE-ACS and in 182 (60%) of STEMI patients with subsequent PCI in 81 (22%) and 156 (51%), respectively. Overall mortality rates were 17% in-hospital and 39% at 1-year follow-up. PCI was independently associated with a decreased risk of 1-year all-cause death [hazard ratio (HR) 0.57, 95% confidence interval (CI) 0.35, 0.95; P < .05], mainly observed in those patients without disability (HR 0.59, 95% CI 0.37, 0.94; P < .01) and lower Killip class (HR 0.50, 95% CI 0.28, 0.89; P < .001).

CONCLUSIONS AND IMPLICATIONS

The prognosis of nonagenarians after an ACS was associated with comorbidities and the therapeutic approach. Although PCI appeared to be a safe and effective strategy, it is still necessary to refine the decision-making process in this high-risk population group.

A new approach to ticagrelor-based de-escalation of antiplatelet therapy after acute coronary syndrome. A rationale for a randomized, double-blind, placebo-controlled, investigator-initiated, multicenter clinical study

The risk of ischemic events gradually decreases after acute coronary syndrome (ACS), reaching a stable level after 1 month, while the risk of bleeding remains steady during the whole period of dual antiplatelet treatment (DAPT). Several de-escalation strategies of antiplatelet treatment aiming to enhance safety of DAPT without depriving it of its efficacy have been evaluated so far. We hypothesized that reduction of the ticagrelor maintenance dose 1 month after ACS and its continuation until 12 months after ACS may improve adherence to antiplatelet treatment due to better tolerability compared with the standard dose of ticagrelor. Moreover, improved safety of treatment and preserved anti-ischemic benefit may also be expected with additional acetylsalicylic acid (ASA) withdrawal. To evaluate these hypotheses, we designed the Evaluating Safety and Efficacy of Two Ticagrelor-based De-escalation Antiplatelet Strategies in Acute Coronary Syndrome - a randomized clinical trial (ELECTRA-SIRIO 2), to assess the influence of ticagrelor dose reduction with or without continuation of ASA versus DAPT with standard dose ticagrelor in reducing clinically relevant bleeding and maintaining anti-ischemic efficacy in ACS patients. The study was designed as a phase III, randomized, multicenter, double-blind, investigator-initiated clinical study with a 12-month follow-up (ClinicalTrials.gov Identifier: NCT04718025; EudraCT number: 2020-005130-15).

ANalgesic Efficacy and safety of MOrphiNe versus methoxyflurane in patients with acute myocardial infarction: the rationale and design of the ANEMON-SIRIO 3 study: a multicentre, open-label, phase II, randomised clinical trial

INTRODUCTION

The unfavourable influence of morphine on the pharmacokinetics of ticagrelor resulting in weaker and retarded antiplatelet effect in patients with acute coronary syndrome (ACS) has been previously shown. Replacing morphine with methoxyflurane, a potent, non-opioid analgesic agent, that does not weaken or delay the effect of antiplatelet agents may improve the clinical efficacy of treatment of patients with ACS.

METHODS

The ANEMON-SIRIO 3 study was designed as a multicentre, open-label, phase II, randomised clinical trial aimed to test the analgesic efficacy and safety of methoxyflurane in patients with ACS. The study population will comprise patients with ST-elevation myocardial infarction or non-ST-elevation ACS admitted to the study centres with typical chest pain requiring analgesic treatment. Before percutaneous coronary intervention (PCI) for the patients with index ACS will be randomly assigned in 1:1 ratio to receive methoxyflurane administered by inhalation, or to obtain morphine administered intravenously. Analgesic treatment will be followed by 300 mg loading dose of aspirin and 180 mg loading dose of ticagrelor. Patients will be assessed with regard to pain intensity according to the Numeric Pain Rating Scale at baseline, 3 min after study drug administration and immediately after PCI. Moreover, patients will be actively monitored with regard to the occurrence of side effects of evaluated therapies, as well as adverse events that may be related to insufficient platelet inhibition (no-reflow phenomenon assessed immediately after PCI, administration of GPIIb/IIIa inhibitors during PCI, acute stent thrombosis).

ETHICS AND DISSEMINATION

The study will be conducted in six Polish clinical centres from the beginning of in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

TRIAL REGISTRATION DETAILS

ClinicalTrials.gov, NCT04476173.

Pharmacodynamic and clinical efficacy of reduced ticagrelor maintenance doses in patients with coronary artery disease

OBJECTIVE

An increasing body of data indicates that a reduction of ticagrelor maintenance dose (MD) in stabilized patients might improve ticagrelor's safety profile and adherence to the treatment. The aim of this review was to discuss the rationale and summarize the current pharmacodynamic and clinical outcomes-based evidence from reduced MD of ticagrelor in patients with coronary artery disease (CAD).

METHODS

A narrative systematic review based on a literature search using the PubMed database from its inception through to June 2020. A search strategy included a combination of relevant search terms regarding ticagrelor reduced MD. The pre-determined inclusion criteria were: (1) randomized or observational trials; (2) presentation of clinical or pharmacodynamic results; (3) evaluation of any ticagrelor MD below 90 mg BID in patients with CAD.

RESULTS

Studies evaluating the following ticagrelor reduced MD have been identified: 90 mg QD, 60 mg BID, 60 mg QD, 45 mg BID, 22.5 mg BID. Majority of trials assessing doses <60 mg BID were performed in Asian patients only. Antiplatelet effect of ticagrelor in CAD decreases with the dose, however even reduced MDs provide sufficient platelet inhibition, which is greater than in clopidogrel-treated patients. De-escalation of ticagrelor dose shows a propensity towards a reduced rate of bleeding and non-bleeding adverse events.

CONCLUSIONS

Ticagrelor doses below 90 mg BID generally show an acceptable profile of platelet inhibition. The number of studies reporting clinical outcomes in CAD patients receiving reduced MD of ticagrelor are limited, however available results indicate that in a stable setting this strategy offers improved safety with preserved efficacy in the prevention of thrombotic events.

Prolonged antithrombotic therapy in patients after acute coronary syndrome: A critical appraisal of current European Society of Cardiology guidelines

The increased risk of non-cardiovascular death in patients receiving clopidogrel or prasugrel in comparison with the placebo group in the Dual Antiplatelet Therapy (DAPT) trial in contrast to the decreased risk of cardiovascular death and all-cause death seen in patients treated with low-dose ticagrelor in the EU label population of the PEGASUS-TIMI 54 trial, resulted in inclusion in the 2020 ESC NSTE-ACS guidelines the recommendation for use of clopidogrel or prasugrel only if the patient is not eligible for treatment with ticagrelor. The prevalence of the primary outcome composed of cardiovascular death, stroke, or myocardial infarction was lower in the low-dose rivaroxaban and acetylsalicylic acid (ASA) group than in the ASA-alone group in the COMPASS trial. Moreover, all-cause mortality and cardiovascular mortality rates were lower in the rivaroxaban-plus-ASA group. Comparison of the PEGASUS-TIMI 54 and COMPASS trial patient characteristics clearly shows that each of these treatment strategies should be addressed at different groups of patients. A greater benefit in post-acute coronary syndrome (ACS) patients with a high risk of ischemic events and without high bleeding risk may be expected with ASA and ticagrelor 60 mg b.i.d. when the therapy is continued without interruption or with short interruption only after ACS. On the other hand, ASA and rivaroxaban 2.5 mg b.i.d. seems to be a better option when indications for dual antithrombotic therapy (DATT) appear after a longer time from ACS (more than 2 years) and/or from cessation of DAPT (more than 1 year) and in patients with multiple vascular bed atherosclerosis. Thus, both options of DATTs complement each other rather than compete, as can be presumed from the recommendations. However, a direct comparison between these strategies should be tested in future clinical trials.

State of the Art: No-Reflow Phenomenon

Primary percutaneous coronary intervention is the preferred reperfusion strategy for the management of acute ST-segment elevation myocardial infarction. No reflow is characterized by the inadequate myocardial perfusion of a given segment without angiographic evidence of persistent mechanical obstruction of epicardial vessels. Both pharmacologic and device-based strategies have been tested to resolve coronary no reflow. This article provides an updated overview of the no-reflow phenomenon, discussing clinical evidence and ongoing investigations of existing and novel therapeutic strategies to counteract it.

Stratified Approaches to Antiplatelet Therapies Based on Platelet Reactivity Testing

Antiplatelet therapy with P2Y₁₂ receptor inhibitors (clopidogrel, prasugrel, ticagrelor, cangrelor) is a cornerstone of medical therapy after percutaneous coronary interventions. Significant prevalence of high on-treatment platelet reactivity (HTPR) on clopidogrel treatment led to introduction of more potent P2Y₁₂ inhibitors: prasugrel (a third generation thienopyridine), ticagrelor, and cangrelor (cyclopentyl-triazolo-pyrimidines). Nevertheless, more potent platelet inhibition and resulting low on-treatment platelet reactivity (LTPR) has led to increased risk of major bleeding events. These limitations resulted in a need for an individualized antiplatelet therapy approach. This review discusses the current role and future perspectives of diagnostic tools such as platelet function testing to optimize antiplatelet therapy with a focus on deescalating therapies to reduce bleeding risks.