The introduction of drug-eluting stents (DES) into the armamentarium of percutaneous coronary intervention (PCI) has reduced in-stent restenosis. Currently, PCI with DES has become a standard-of-care procedure in patients with acute and chronic coronary syndromes. Table 1 lists the features of contemporary coronary stents available in Japan in 2023. The first-generation DES were made of stainless steel, while contemporary DES mainly consist of different kind of alloys such as cobalt chromium and platinum chromium. In the current generation DES, thinner struts are employed than in the first-generation DES (> 130 μm) with preserved radial strength and radio-opacity. The lower strut thickness is believed to be associated with better stent-related outcomes including target lesion revascularization, myocardial infarction, and stent thrombosis [1, 2]. The number of links (connectors) between hoops has an impact on stent flexibility, deliverability and conformability, and possibly clinical events [2]. Current generation DES include both durable and biodegradable polymer-coated stents, and the lifelong presence of durable polymer is reported to be related to chronic inflammation and neoatherosclerosis [3]. To overcome this potential limitation of durable polymer, biodegradable polymer DES have been developed. To date, numerous clinical trials have shown the safety of biodegradable polymer DES compared with durable polymer DES, but their clinical benefit is unclear [4, 5]. DES polymer is applied to the surface circumferentially or only at the abluminal side. Limiting the polymer to the abluminal aspect of the stent reduces total polymer burden, although whether this technology leads to better clinical outcomes is also unknown. Different immunosuppressive and anti-cancer agents are used as anti-restenotic drugs in DES to inhibit smooth muscle proliferation. There is a stent that has an additional circumferential layer of anti-CD 34 antibodies on the stent struts on top of the polymer to capture circulating endothelial progenitor cells, conceptually leading to better endothelial healing. However, the clinical evidence is limited [6]. Beyond polymer-based DES, polymer-free DES and a drug coated coronary stent have been emerged. With no polymer, abluminally coated probucol regulates the release of sirolimus in the former, while the latter has the micro-structured abluminal surface in which an anti-restenotic drug is directly applied.

Table 1 Drug-eluting and coated stents
Full size table

Coronary stent technologies have evolved enormously in the past decades from bare metal stents to contemporary DES, achieving safer and more effective devices for all patient and lesion subsets undergoing PCI. However, short- and long-term stent-related adverse events continue to accrue even in PCI with contemporary DES [7]. In the future, the use of novel technologies may provide better clinical outcomes.