Elderly patients are hyperresponsive to potent P2Y12 inhibitors

Abstract Background Aging has recently been associated with increased basal platelet activation and adenosine diphosphate (ADP) hyperreactivity on the one hand, but decreased platelet response to thrombin receptor stimulation on the other hand in individuals without antiplatelet therapy. In the current study, we investigated platelet response to agonist stimulation in elderly patients (70 years or older) on dual antiplatelet therapy with potent P2Y12 inhibitors. Methods Platelet aggregation in response to arachidonic acid (AA), ADP, collagen, the protease-activated receptor (PAR)-1 agonist SFLLRN and the PAR-4 agonist AYPGKF was assessed by multiple electrode aggregometry in 79 prasugrel- and 77 ticagrelor-treated patients 3 days after acute percutaneous coronary intervention. Results In the overall study population (n=156), patients aged ≥70 years (n=33) had lower platelet aggregation in response to AA, ADP and SFLLRN than younger patients (all p<0.05). In prasugrel-treated patients (n=79), those aged ≥70 years (n=13) showed significantly lower platelet aggregation in response to all agonists compared to younger patients (all p<0.05). In contrast, in ticagrelor-treated patients (n=77), those aged ≥70 years (n=20) only had significantly lower ADP-inducible platelet aggregation than younger patients (p=0.03), whereas platelet aggregation in response to AA, collagen, SFLLRN and AYPGKF was similar between elderly and younger patients on ticagrelor (all p>0.05). Among patients aged ≥70 years, prasugrel-treated patients showed significantly lower platelet aggregation in response to AA, collagen and AYPGKF than those receiving ticagrelor (all p<0.05). Conclusion Patients aged ≥70 years on potent P2Y12 inhibitors exhibit increased inhibition of ADP-inducible platelet aggregation. In addition, elderly patients on prasugrel show a significantly lower response to AA, collagen, SFLLRN and AYPGKF than younger patients.Platelet aggregation prasugrel patientsPlatelet aggregation ticagrelor patients