Case Study: Xience V

4. Abbott Vascular - Xience V

4.1 - Background

Xience V is an everolimus-eluting stent that was FDA approved in 2007, and has since been considered the second generation of drug eluting stents. The backbone in Xience V (Figure 3) is a copolymer comprised of vinylidene fluoride and hexafluoropropylene [16]. The stent consists of a Multi-Link Vision cobalt chromium (CoCr), and is coated with the active component everolimus [6]. The cobalt-chromium backbone is a unique feature, and why this stent was selected. Everolimus is a derivative of sirolimus, and acts as an immunosuppressant. A variety of Xience stents exist that differ in size, diameter, and length [16].

4.2 - Device Process

The cobalt-chromium balloon stent is delivered through a major artery using balloon angioplasty. The Multi-Link Vision stent is connected by serpentine rings from a single piece of medical grade L-605 CoCr alloy [16].

The effectiveness of the stent was tested in a clinical trial, in which 267 patients

It is produced by the pharmaceutical company Abbott, and was FDA approved in July of 2016 [20]. The fully bioresorbable scaffold contains a polymer platform 150 µm thick made from polylactic acid (PLLA) and a poly-D,L-lactide (PDLLA) layer for rapid degradation. The PDLLA eludes the drug everolimus at a concentration of 8.2 µg/mm to prevent restenosis [3,5]. Within the first 30 days of implantation, approximately 80% of the everolimus is released, followed by a more gradual release of the remaining 20% [3].

Figure 4: Through the first 6 months, bioresorption maintains the mechanical support of the lumen. Over the next two years, the scaffold’s struts are replaced by connective tissue, and by 3 years, no polymer remains in the vessel. After 4 years, the arterial wall will have regained full function [20].
5.2 - Device