Impact of high maintenance dose of clopidogrel on clinical outcomes in ST-elevation myocardial infarction patients after primary percutaneous coronary intervention

Objective To study whether an increase in clopidogrel maintenance dose results in increased inhibition of platelet aggregation on patients after primary percutaneous coronary intervention (PCI) for acute ST-elevation myocardial infarction (STEMI), and to assess whether a high maintenance dose of clopidogrel can attain an increasing reduction of hs-CRP concentration which can further influence clinical outcomes.Methods One hundred consecutive STEMI patients after primary PCI were enrolled in this study. They were randomized to receive clopidogrel 150 mg/day or 75 mg/day for 7 days.Platelet aggregation were evaluated at baseline and on the seventh day after PCI respectively with Thrombelastograph (TEG) and the hs-CRP concentration were assessed simultaneously. Patients were followed up for 30 days to record clinical outcomes. Platelet aggregation, hs-CRP concentration and clinical outcomes were analyzed. Results Baseline clinical and angiographic characteristics were similar between the 2 groups. Baseline platelet aggregation and baseline hs-CRP concentration were similar (P=0.871 and P=0.226,respectively). High maintenance dose of clopidogrel was associated with a lower platelet aggregation (40.29±22.47% vs 50.42±21.39%,P=0.023) and a greater decrease in hs-CRP concentration (1.65±1.06 mg/L vs 1.00±0.79 mg/L, P=0.001).There was a correlation between the inhibition of platelet aggregation and the decrease of hs-CRP level (r=0.21, P=0.043). However, no significant clinical benefit was observed with high maintenance dose of clopidogrel. Conclusion Administration of a 150mg maintenance dose of clopidogrel results in more intense inhibition of platelet aggregation than administration of 75 mg maintenance dose. High maintenance dose of clopidogrel associated with greater decrease of hs-CRP level. However, no significant clinical benefit was acquired with high clopidogrel maintenance dose in short term evaluation.