Frequency of nonresponse antiplatelet activity of clopidogrel during pretreatment for cardiac catheterization.

Platelet function was evaluated before and after clopidogrel therapy in 50 cardiology candidates scheduled for intervention; results were averaged from optical platelet aggregation with 2 significantly correlated point-of-care instruments, Thrombelastograph and Ichor PlateletWorks. Although this was a limited study with few complications, the failure of clopidogrel therapy (30% nonresponders with <10% average platelet inhibition) was not correlated with clinical pretreatment variables, including atorvastatin therapy, postintervention bleeding complications, or major adverse coronary events.