Hypoactivation effects in patients with myocardial infarction with ST-segment elevation in the substitution of clopidogrel for ticagrelor
The aim of this study was to investigate platelet aggregation in patients with myocardial infarction with ST-segment elevation (STEMI) in case of replacement of clopidogrel by a new class of inhibitors of P2Y12 receptor (ticagrelor) during the hospital period. Materials and methods. The study included 80 patients with STEMI. At the stage of emergency medical care all patients received a load dose of aspirin (250 mg) and clopidogrel (600 mg). Subsequently the patients were divided into two groups by random sampling. Patients of Group 1 received the maintenance dose of clopidogrel 75 mg/day, patients of Group 2 - the maintenance dose of ticagrelor 90 mg 2 p/day. Platelet aggregation was studied before replacement of the drug, 2 hours after it and on Day 7. Results. This article at study of platelet aggregation before replacement of clopidogrel by ticagrelor no significant differences of hypoactivation effect in the group of clopidogrel and ticagrelor with any of the inducers (ADP 1.25 and 2.5 mcg/ml, adrenaline (epinephrine), collagen, ristocetin) were identified. In 2 h after replacement of drugs platelet aggregation in groups with all the inductors also was not significantly different. On day 7, the ADP-induced (1,25 µg/ml, 2.5 µg/ml) platelet aggregation in the ticagrelor group was significantly lower compared to the aggregation of platelets in the clopidogrel group. ADP-induced 1,25 µg/ml platelet aggregation was as follows: clopidogrel - 34.8 (23; 47.9)%, ticagrelor - 20.45(11.8; 28,4)%; p =0.001. ADP-induced 2.5 µg/ml platelet aggregation were: clopidogrel - of 45.61 (32.7; 56)%, ticagrelor - to 30.3 (13.3; 41.6)%; p =0.008. Conclusion. When replacing clopidogrel bt ticagrelor in patients with STEMI anti-platelet effect on Day 7y is higher than the anti-platelet effect in a group of patients who continued taking clopidogrel.