This is a randomized, double-blind, placebo-controlled crossover study of aspirin 81 mg once daily and clopidogrel 75 mg once daily. Platelet function is assessed with plasma P-selectin levels and aggregometry after exposure to adenosine diphosphate, arachidonic acid, and collagen. We will assess serum levels of thromboxane B2 and urinary metabolites of thromboxane A2 and prostaglandin I2 (Tx-M and PGI-M, respectively).
