Bioresorbable Scaffolds: Opportunities Missed, Lessons Learned, and Future Perspectives.

Coronary stents have dramatically improved the treatment of coronary artery stenosis. In-stent-restenosis (ISR) and stent thrombosis (ST) pose major obstacles to the success of coronary stenting. Drug-eluting stents (DES) emerged as a major breakthrough in stenting and significantly reduced ISR. Despite taking dual antiplatelet therapy (DAPT), very late ST has remained a major obstacle in the success of DES. This occurs regardless of the type of polymer or antiproliferative agent in the contemporary stents. Such adverse events occur at a rate of approximately 2% to 3% per year after first year, which have been attributed to the strut fractures, loss of vessel compliance and vasomotion, and neoatherosclerosis. Fully bioresorbable scaffolds (BRS) have emerged in an effort to overcome these limitations leading to a "leave nothing behind" approach. While appealing, the initial experience with BRS technology was hampered by increased rates of BRS thrombosis compared with DES. In this review, we summarized underlying mechanisms leading to BRS failure and provided insights into optimizing BRS deployment with intravascular imaging. In addition, we outlined the perspectives of new generations BRS with thinner struts and new designs as well as alternative materials to improve outcome.