The DAPT Study is a double blind randomized controlled trial intended to determine the appropriate duration for dual antiplatelet therapy (the combination of aspirin and a second anti-clotting medication) as well as the safety and effectiveness of dual antiplatelet therapy to protect patients from stent thrombosis and major adverse cardiovascular and cerebrovascular events (MACCE) following the implantation of drug-eluting coronary stents. Similar analysis will be conducted in a smaller cohort of bare metal coronary stent – treated subjects.