JAMA -

"Antiplatelet Therapy Duration Following Bare Metal or Drug-Eluting Coronary Stents The Dual Antiplatelet Therapy Randomized Clinical Trial"

"Conclusions and Relevance  Among patients undergoing coronary stent placement with BMS and who tolerated 12 months of thienopyridine, continuing thienopyridine for an additional 18 months compared with placebo did not result in statistically significant differences in rates of stent thrombosis, MACCE, or moderate or severe bleeding. However, the BMS subset may have been underpowered to identify such differences, and further trials are suggested."   

https://jama.jamanetwork.com/article.aspx?articleid=2203799