Coronary Stents: History, Design, and Construction

Abstract

The history of percutaneous coronary intervention (PCI) is marked by rapid technological advancements that have taken place over the past 40 years. After a period of balloon angioplasty, which was marred by risk of abrupt vessel closure and vessel recoil, balloon expandable metal alloy stents were the mainstay of PCI. The introduction of drug eluting stents (DES) targeted in-stent restenosis, a common mode of stent failure, and ushered in the current PCI era. Since the first generation of DES, advances in polymer science and stent design have advanced the field. The current generation of DES has thin struts, are highly deliverable, have biocompatible or absorbable polymers, and outstanding safety and efficacy profiles. In this review, we discuss the technological advancements in stent development, design, and construction, with an emphasis on balloon expandable stents. The aspects of stent properties, metal alloys, bioresorbable vascular scaffolds, drug elution, and polymers will be covered.

Keywords: drug elution; percutaneous coronary intervention; polymer; stents.

Figure 1

Schematic of components of coronary stent. Coronary stents are composed of a scaffold, delivery vehicle for anti-proliferative agent, and an anti-proliferative agent.

Figure 2

Graphic representation of the clinical correlates of the stent characteristics. Metallic choice influences the strut thickness which in turn affects radial strength, radio-opacity, and inflammation. The cell size and design (open versus closed cell) affects the ability to access the side branches and scaffold the artery, while distributing the antiproliferative agent to the vessel wall.