Double antiplatelet therapy in patients with acute coronary syndrome after percutaneous coronary intervention: individual efficacy and hemorrhagic safety of P2Y12 blockers of ticagrelor and clopidogrel in actual clinical practice

Aim . To study the comparative efficacy and safety of clopidogrel and ticagrelor in the “double” antiplatelet therapy (DATT) in patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) in the early and late periods in real clinical practice, and to assess adherence to treatment. Materials and methods . The study included 109 patients with ACS, who underwent PCI. Patients were divided into two groups: the 1st group (n=57) – received ticagrelor and the 2nd group (n = 52) – received clopidogrel in the DATT for 12 months. The frequency of ischemic events (death from cardiovascular causes, repeated myocardial infarction (MI) and stent thrombosis (ST)) and hemorrhagic events was analyzed during hospitalization, in 3 months, 6 months and in 12 months. Also, the reasons of repeated hospitalizations during the year were analyzed. The adherence of patients was assessed using the Moriski–Green scale. Results . There were no significant differences in the ticagrelor and clopidogrel groups (8.8% vs. 11.5%, p=0.87) for the incidence of stent thrombosis (ST). In the correlation analysis, in half of all cases of subacute ST in the total sample (n=109) (in 4 (3.65%) cases from 8 (7.3%)), the main reason for its development was the lack of adherence of patients to DATT (τ=0,6; p<0,001). The frequency of minor bleeding significantly prevailed in the ticagrelor group versus the clopidogrel group (38.6% vs. 21.2%, p=0.047). No significant difference in the rates of major bleeding was found between the ticagrelor and clopidogrel groups (1.8% and 1.9%, p=0.52). However, the difference in the rates of fatal bleeding, including more instances of fatal intracranial bleeding (1.8% vs. 0%; p=0,34), allows us to talk about the best hemorrhagic safety of clopidogrel. Conclusion . In this study, ticagrelor and clopidogrel were comparable in their effectiveness. Ischemic events and repeated hospitalizations in both groups are associated with the progression of atherosclerosis, confirmed by angiography; the development of stent restenosis, as well as low adherence, which is the main predictor of subacute TS. In addition, clopidogrel versus ticagrelor showed better hemorrhagic safety in the frequency of development of minor bleeding.