Visit 2: After 4 weeks of taking STE or ASA the patients visited the hospital for the second visit. All examinations from visit 1, including platelet aggregation inhibition assays, were repeated. Whole blood samples were collected 1-4 h after the ingestion of a morning ASA or STE dose from a peripheral vein using a 21 gauge or larger needle in a partial fill 3.2% citrate vacuum collection tube.