Factors influencing platelet aggregation in patients with acute coronary syndrome

Abstract To study factors influencing platelet aggregation in patients with acute coronary syndrome (ACS). The investigation enrolled 147 patients with ACS. Their blood was sampled on days 1, 3-5, and 8-12 days after the onset of ACS. All the patients received acetylsalicylic acid (ASA) 300 mg on day 1, then 100 mg/day and clopidogrel 300-600 mg on day 1, then 75-150 mg/day. Platelet aggregation was analyzed in 65 patients on day 1 after ASA intake, but prior to clopidogrel therapy. The aggregation was induced by 5 and 20 pmol of ADP. With the use of clopidogrel 75 mg/day on day 3-5, platelet aggregation was reduced by 2.1 and 1.7 times for 5 and 20 μmol of ADP, respectively, as compared to day 1 (ASA without clopidogrel) and remained unchanged on days 8-12. Increasing the dose of clopidogrel up to 150 mg/day potentiated its antiaggregatory effect. On day 1 (ASA without clopidogrel), there was a direct correlation between platelet aggregation levels and mean platelet volume (MPV) (correlation coefficients (r), 0.526 (p