The mechanisms of late scaffold thrombosis

Coronary scaffolds have been recently developed to address the long-term limitations of metallic drug eluting stents. Concerns have however been expressed on the safety of these devices, with evidence of both early and late scaffold thrombosis. While early thrombosis has been associated with incomplete scaffold expansion, leading to flow disturbances, blood recirculation, and platelet activation, the pathophysiology of late events remains less understood. Recent cases series have shown that malapposition and scaffold dismantling might play a role in this phenomenon, an observation that further confirms the importance of an accurate implantation. Further, the role of dual antiplatelet therapy, and whether prolonging it may reduce event rates, remains to be elucidated. As well, the role of inflammatory phenomena has been proposed but never demonstrated. This brief review summarizes the current evidence on these phenomena.