Impact of aspirin dose on adenosine diphosphate-mediated platelet activities. Results of an in vitro pilot investigation

P2Y12 Inhibitor Monotherapy Combined With Colchicine Following PCI in ACS Patients: The MACT Pilot Study

BACKGROUND

After a brief period of dual antiplatelet therapy, P2Y12 inhibitor monotherapy in the absence of aspirin effectively reduces bleeding without increasing recurrent ischemia in patients undergoing percutaneous coronary intervention (PCI). In addition, early anti-inflammatory therapies may have clinical benefits in acute coronary syndrome (ACS) patients.

OBJECTIVES

The aim of this study was to investigate the feasibility of ticagrelor or prasugrel P2Y12 inhibitor monotherapy combined with colchicine immediately after PCI in patients with ACS.

METHODS

This was a proof-of-concept pilot trial. ACS patients treated with drug-eluting stents were included. On the day after PCI, low-dose colchicine (0.6 mg daily) was administered in addition to ticagrelor or prasugrel maintenance therapy, whereas aspirin therapy was discontinued. The primary outcome was any stent thrombosis at 3 months. The key secondary outcomes were platelet reactivity measured by the VerifyNow assay (Accriva) before discharge and a reduction in high-sensitivity C-reactive protein (hs-CRP) over 1 month.

RESULTS

We enrolled 200 patients, 190 (95.0%) of whom completed the 3-month follow-up. The primary outcome occurred in 2 patients (1.0%): 1 definite and 1 probable stent thrombosis. The level of platelet reactivity overall was 27 ± 42 P2Y12 reaction units, and only 1 patient had high platelet reactivity (>208 P2Y12 reaction units). The hs-CRP levels decreased from 6.1 mg/L (IQR: 2.6-15.9 mg/L) at 24 hours after PCI to 0.6 mg/L (IQR: 0.4-1.2 mg/L) at 1 month (P < 0.001), and the prevalence of high-inflammation criteria (hs-CRP ≥2 mg/L) decreased from 81.8% to 11.8% (P < 0.001).

CONCLUSIONS

In ACS patients undergoing PCI, it is feasible to discontinue aspirin therapy and administer low-dose colchicine on the day after PCI in addition to ticagrelor or prasugrel P2Y12 inhibitors. This approach is associated with favorable platelet function and inflammatory profiles. (Mono Antiplatelet and Colchicine Therapy [MACT]; NCT04949516).

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.

Blood cells: an historical account of the roles of purinergic signalling

The involvement of purinergic signalling in the physiology of erythrocytes, platelets and leukocytes was recognised early. The release of ATP and the expression of purinoceptors and ectonucleotidases on erythrocytes in health and disease are reviewed. The release of ATP and ADP from platelets and the expression and roles of P1, P2Y(1), P2Y(12) and P2X1 receptors on platelets are described. P2Y(1) and P2X(1) receptors mediate changes in platelet shape, while P2Y(12) receptors mediate platelet aggregation. The changes in the role of purinergic signalling in a variety of disease conditions are considered. The successful use of P2Y(12) receptor antagonists, such as clopidogrel and ticagrelor, for the treatment of thrombosis, myocardial infarction and stroke is discussed.