APPROACH In the genotype guided arm, a buccal swab will be obtained from subjects immediately following PCI/stent, to determine CYP2C19 genotype with the SpartanRx system. Subject with slow metabolizer status [1 or 2 loss-of-function (LOF) mutations (*2 or *3) in CYP2C19] will be recommended to initiate therapy with prasugrel or ticagrelor in place of clopidogrel. Subjects with normal metabolizer status (homozygous for the *1 allele in CYP2C19) will be recommended to initiate therapy with clopidogrel. Antiplatelet choice is ultimately decided by physician judgment incorporating all clinical factors.