Part I: A Survey of Current and Future Generation Drug-Eluting Stents: Meaningful Advances or More of the Same?

Analyst projections for the drug-eluting stent (DES) market estimated that the total number of DES implanted in 2010 would go beyond 4.5 million worldwide. Although the initial results seemed promising, longer-term follow-up in a broader range of patients revealed some pitfalls. Delayed neointimal growth, enhanced platelet aggregation, a local hypersensitivity reaction against the polymer coating, stent fracture, and a failure of sirolimus-, paclitaxel-, and tacrolimus-eluting stents to reduce neointimal hyperplasia at 90 and 180 days in animals, when the drug was completely eluted from the stent, are just several examples.1–8 The number of stents currently under investigation is substantial. They are all loaded with drugs that interfere with pathways in the process of inflammation and neointimal proliferation. However, the process of restenosis is a sequence of complex events that has been only partly elucidated over the last 2 decades.9 Locally acting DES provide the opportunity to interfere with the various mechanisms responsible for each step in the restenotic cascade, and a wide variety of different agents are currently available. Although only sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) have received US Food and Drug Administration (FDA) approval to date, multiple alternative devices are attempting to find their way to achieve the same goal, namely a reduction of restenosis and the need for repeat interventions.