Association between Mean Platelet Volume and Resistance to Aspirin and P2Y12 Receptor Inhibitors in Elderly Patients with Acute Coronary Syndrome

Background: Antiplatelet resistance and mean platelet volume (MPV) are event predictors in acute coronary syndrome (ACS), buttheir association has been poorly studied.Objective: The aim of this study was to evaluate the association between MPV and resistance to aspirin (ASA) and P2Y12 receptorinhibitors (P2Y12i) in elderly patients with ACS.Methods: Patients over 65 years old diagnosed with ACS were included in the study. They were divided into group 1 (resistance toboth antiplatelet agents), group 2 (resistance to one antiplatelet agent) and group 3 (no resistance to antiplatelet agents). Plateletaggregation was measured between 12 and 24 hours postloading (by light transmission aggregometry). Resistance to P2Y12i wasconsidered as maximum percentage of aggregation (MPA) with adenosine diphosphate (ADP) >60% and resistance to ASA as MPAwith arachidonic acid (ARA) >20%. The composite endpoint of global death and cardiovascular re-hospitalization was consideredduring follow-up.Results: One hundred and ninety five patients included in the study received ASA and P2Y12i (120 received clopidogrel and 75ticagrelor). Nineteen percent of patients belonged to group 1, 34.4% to group 2 and 46.6% to group 3. Mean platelet volume wasassociated with resistance to both antiplatelet agents [OR 1.02 (95% CI 1.01-1.05), p=0.03], while MPV and the GRACE score wereindependent predictors of the composite endpoint [HR 1.03 (95% CI 1.01-1.07), p=0.04, and HR 1.02 (95% CI 1.01-1.04), p=0.02,respectively].Conclusions: Mean platelet volume was associated with the presence of resistance to both antiplatelet agents. During follow-up,MPV and the GRACE score were predictors of the composite endpoint.