Very late stent thrombosis: current concepts.

PURPOSE OF REVIEW: Drug-eluting stents (DES) are effective in reducing neointimal proliferation and in-stent restenosis. However, the procedure is complicated by early and late stent thrombosis that is related to incomplete healing, leading to stent malapposition and incomplete reendothelialization. Stent restenosis results in significant mortality and morbidity and portends a poor long-term outcome. In this article, we review recent findings regarding the prevalence of late and very late stent thrombosis (VLST) and the mechanisms that may be at play.

RECENT FINDINGS: Long-term follow-up from large registry studies and randomized controlled trials of DES implantation have recently created an awareness of the persistence of VLST (0.26%/year) for up to at least 5 years. Recent findings utilizing intravascular ultrasound and optical coherence tomography have also provided important insights into the mechanism of VLST and suggest that delayed healing and neoatherosclerosis are important. Finally, the development of novel stent scaffolds and antiplatelet agents holds much promise for reducing the risk of VLST.

SUMMARY: DES implantation continues to be complicated by the risk of VLST. Recent insights into the mechanisms of this significant clinical problem have important implications in preventing VLST.