Abstract: Objective:To assess aspirin efficacy in the early postoperative period. Methods:Sixty patients undergoing OPCAB surgery were enrolled in the study. Functional and biochemical responses to aspirin were evaluated by arachidonic acid (ARA)-induced platelet aggregation and urine 11-DH-TXB2 metabolite excretion. Previous aspirin treatment was terminated 5-7days before OPCAB and continued at the day with food intake after surgery. Samples were collected before and on days 1, 4 and 10 after aspirin intake(100mg/d). Results:Patients with aspirin resistance on days 1,4and 10 were 17,9 and 2, separately, and the level of platelet aggregation was stable on the 4th day after aspirin intake. Conclusion:Aspirin did not sufficiently inhibit platelet aggregation early after OPCAB. It is important to keep potential anti-coagulation therapy in the early postoperative period.

Key words: coronary artery bypass grafting surgery, aspirin resistance , platelet aggregation