This study builds, in part, upon preliminary results generated as part of the Pharmacogenomics Anti-Platelet Intervention (PAPI) Study (NCT00799396). The purpose of this investigation is to assess the impact of genetic variation in the carboxylesterase 1 (CES1) on response to clopidogrel as well as dual antiplatelet therapy (i.e. clopidogrel and aspirin), as assessed by ex vivo platelet aggregometry, in healthy Amish individuals. The investigators hypothesize that participants who carry alleles that modify the activity or expression of CES1 will have altered response to clopidogrel as well as dual antiplatelet therapy.

Inclusion Criteria:

• Age 20 years or older
• Of Old Order Amish descent

Exclusion Criteria:

• Currently pregnant or less than 6 months have passed since delivery
• Currently breast feeding
• Has a history of a bleeding disorder or major spontaneous bleed, such as peptic ulcer, epistasis, or intracranial bleed
• Has severe hypertension, defined by a blood pressure above 160/95 mm Hg
• Takes medications that would affect the outcome(s) to be measured and cannot willingly and safely, in the opinion of the treating physician and study physician, discontinue these medications for 1 week prior to protocol initiation
• Is taking vitamins or other supplements and is unwilling to discontinue use for at least 1 week prior to study
• Has a coexisting malignancy
• Has a creatinine level greater than 2.0 mg/dl, aspartate transaminase (AST) or alanine transaminase (ALT) greater than two times the upper limit of normal, hematocrit less than 32%, or a thyroid-stimulating hormone (TSH) less than 0.4 or greater than 5.5 mIU/L
• Has a bleeding disorder or history of gastrointestinal bleeding or other major bleeding episode
• Is currently taking aspirin, clopidogrel, or anti-coagulants, such as warfarin, heparin, or GPIIb/IIIa antagonists, and have conditions that might place the participant at increased risk from withdrawal of these medications 14 days prior to protocol initiation
• History of unstable angina, heart attack, angioplasty (including stent placement), coronary artery bypass surgery, atrial fibrillation, stroke or transient ischemic attacks, diabetes, or deep vein thrombosis or other thrombosis
• Has polycythemia, or thrombocytosis, defined by a platelet count greater than 500,000
• Has thrombocytopenia, defined by a platelet count less than 75,000
• Has had surgery within the last 6 months
• Has an aspirin or clopidogrel allergy

Yes

It is possible that deidentified data will be deposited into large public databases as per NIH data sharing policies (e.g. dbGAP, PharmGKB). Data to be shared would include, but not limited to, anthropometric data, study outcome data, and relevant covariate data used in statistical models of association. It is anticipated that data would be available after the completion of the trial. The data will be obtained from the participants and the study-related research procedures.

37 days

Adverse event data were collected during both intervention periods and for 30 days after the final study visit.