XIENCE V™ Stent Design and Rationale

Drug‐eluting stents (DES) are a preferred treatment modality for occlusive coronary artery disease. First‐generation DES have demonstrated high levels of efficacy. However, concerns have been raised over late thrombotic events. XIENCE V™ everolimus‐eluting coronary stent is a second‐generation DES designed to be more deliverable and safe, while maintaining efficacy in a broad patient population compared with first‐generation DES. 1 − 3 As a drug/device combination product, the overall performance of a DES is determined by its components and how well they are integrated. XIENCE V utilizes the MULTI‐LINK VISION ® stent, the antiproliferative drug everolimus, a fluorinated polymer drug carrier, poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP), and a stent‐specific delivery system. A DES coating must fulfill the multiple goals of biocompatibility, controlled drug release and maintenance of the coating durability through stent crimping, and expansion in vivo. The XIENCE V coating utilizes a two‐layer coating system composed of an acrylate primer and a fluorinated copolymer drug reservoir. Fluorinated polymers have a long history of use in permanent vascular implant applications. The XIENCE V fluorinated copolymer offers in vivo biocompatibility combined with excellent chemical stability and high purity. Described in this article are the design rationale and polymer selection criteria. The hemocompatibility and biocompatibility of the fluorinated polymer coating are discussed. Characterization results on drug release control, possible drug release mechanism, coating integrity, coating uniformity, and fatigue resistance are also presented.