Distribution of clinical events across platelet aggregation values in all-comers treated with prasugrel and ticagrelor.

The aim of this study was to investigate the distribution of clinical events across the platelet aggregation values in patients treated with prasugrel and ticagrelor. This prospective observational study enrolled 226 patients treated with prasugrel (n=121) or ticagrelor (n=105). Adenosine diphosphate (ADP)-induced platelet aggregation was determined by Multiplate Analyzer in the maintenance phase of treatment with prasugrel or ticagrelor. Clinical outcome was evaluated over 12 months. Platelet aggregation values were divided into quartiles. The first quartile comprised values <8 U, the second quartile values between 8 U and <15 U, the third one values between 15 U and 23 U, and the forth one values >23 U. Myocardial infarction events were observed in patients within the third quartile of aggregation values (15-23 U), and were not associated with high on-treatment platelet reactivity (HTPR>46 U). All bleeding events occurred in patients with aggregation values ≤ 23 U, which corresponded to the 75 percentile (p=0.031). There was no difference in the distribution of bleeding events between the 1st-3rd quartiles (p=0.873). In conclusion, patients with ADP-induced aggregation values over 23 U (fourth quartile) were at the lowest risk to develop bleeding during the follow-up.