PB2420 EFFICIENCY OF DUAL ANTIPLATELET THERAPY AFTER PERCUTANEOUS CORONARY INTERVENTION

Background: Percutaneous coronary intervention (PCI) is the treatment metod of ischemic heart disease. Platelet hyperactivity is associated with stent thrombosis so this patients need antiplatelet therapy. Such therapy usually includes clopidogrel and aspirin. It might be useful to assess total procoagulant activity using a global coagulation test in patients on dual antiplatelet therapy (DAPT) Aims: To estimate the plasma coagulation potential level in patients with a different response to antiplatelet therapy. Methods: This research included 46 patients after the successful coronary stent placement. All of them were given 75 mg clopidogrel and 150 mg aspirin per day. The antiplatelet therapy efficiency was assessed with light transmission aggregometry performed with a Hronolog 4‐channel platelet aggregometer using the adenosine diphosphate (ADP, 5 μM) and collagen (2 μg/ml) as agonists. Maximal platelet aggregation (MA, %) was determined. Thrombin generation was measured in platelet‐rich plasma by Calibrated Automated Thrombinogram Assay method (CAT) using reagent containing recombinant tissue factor (Trombinoscope BV, The Netherlands) as a trigger. Following parameters were derived: endogenous thrombin potential (ETP, nM‐min), peak thrombin (Peak, nM), and rate of thrombin generation (R, nM/min). STATISTICA 6.0 package was used in data analysis. Results are presented as median with 95% confidence intervals, p < 0.05 was considered statistically significant. Results: The results of aggregometry are presented in table. 30 (65%) patients (group №1) had a significant decrease in aggregation response only to collagen compared with controls, the response to ADP was not considerably lower. 16 (35%) patients (group №2) had a significant decrease in aggregation response to both collagen and ADP. The results of platelet aggregation suggest that the patients in the group №2 were more sensitive to antiplatelet therapy. There was a significant decrease in ETP, Peak and R in the group №2 compared with group №1 (ETP:Мe‐1636,5, CI: 1168,6‐1919,9 vs. Me‐1785,0, CI: 1415,7‐2576,2, p < 0,05; Peak: Me‐112,8, CI: 72,3‐138,9 vs. Me‐134,7, CI: 80,6‐180,2, p < 0,001; R: Me‐9,2, CI: 4,1‐13,3 vs. Me‐ 12,4, CI: 4,5‐21,2, p < 0,01). Summary/Conclusion: Patients with a better sensitivity to DAPT had lower plasma coagulation potential. It might be associated with the lower risk of stent thrombosis in patients with good response to DAPT.. Individual assessment of plasma coagulation potential using thrombin generation test could be useful for prediction of the thrombosis risk in the stent in patients after PCI. More research is clearly needed.