Platelet Reactivity in Patients with Coronary Stenting Treated with Dual Antiplatelet Therapy and after Withdrawal of Clopidogrel: Impact of Bioactive Titanium Stent versus Everolimus-coated Stent

Objective: To study platelet reactivity at different times while on dual antiplatelet therapy (DAPT) with aspirin (ASA) and clopidogrel in patients treated with bioactive stents (TITAN₂ ^®) or everolimus-coated stents (XIENCE V^®) and one month after clopidogrel cessation.

Background: Coronary intervention damages the endothelium and causes platelet response leading to thrombotic occlusion, which is prevented with DAPT.

Methods: We studied 20 patients with bioactive stent and stable ischemia (BAS-SI group); 31 patients with bioactive stent and acute coronary syndrome (BAS-ACS group) and 31 patients with stable ischemia and everolimus-coated stent (EVE group). DAPT was administered (ASA 100 mg/day and clopidogrel 75 mg/day) for one year in BAS-ACS and EVE groups and for 1 month in BAS-SI group. Platelet aggregation induced by different agonists and platelet recruitment were analyzed at different times of DAPT and 1 month after clopidogrel cessation.

Results: After one month of DAPT, platelet aggregation showed no difference between groups; at 12 months of DAPT, the response to collagen and ADP increased in EVE group. Platelet recruitment at 1 month was higher in the BAS-ACS than the other groups; after 12 months, recruitment increased in the EVE group with respect to BASACS. Platelet aggregation and recruitment in diabetics were significantly higher in all situations than in non-diabetic patients. Clopidogrel withdrawal increased ADPinduced aggregation and collagen-induced aggregation and recruitment.

Conclusion: Platelet reactivity in patients with DAPT varies with time, depending on the subset of patients, the type of the stent implanted and the time after implantation.

Keywords: Platelet Activity, Stent, Recruitment, Aggregation, Dual Antiplatelet Therapy, Clopidogrel Withdrawal.