The AXXESS™ Self-Expanding Biolimus A9™ Eluting Stent System for coronary bifurcation lesions

Abstract

Introduction Procedural difficulties during and worse outcome after percutaneous coronary interventions (PCI) in bifurcated lesions are related to the mismatch between the cylindrical shape of balloonexpandable stents and the Y-shape of the bifurcation. Indeed, most available tools and techniques fail to optimally conform to this variable bifurcation anatomy and to restore ideal flow characteristics, making these lesions more prone to restenosis and stent thrombosis. The Biosensors AXXESSTM Biolimus A9TM Eluting Coronary Bifurcation Stent System (AXXESS System) intends to provide an adequate answer to these issues by combining conical shape with self-expanding and -apposing properties as well as limus-mediated antiproliferative effects. Device description and implantation technique The AXXESS System is a self-expanding, conically-shaped laser-cut stent from nitinol (nickel-titanium alloy) in the austenitic (i.e., superelastic) phase with a 0.006-inch (0.15 mm) strut thickness, specifically designed to conform to the anatomy at the level of the bifurcation carina (Figure 1). It has a rapid-exchange delivery system with hydrophilic coating, which allows controlled stent release upon withdrawal of a cover sheath using an actuator. Optimal deployment is guided by progressive flaring of three gold markers at the distal stent edge during unsheathing. Ideally, the stent can be positioned with these markers in both distal branches, allowing easy access for additional branch stenting whenever appropriate. The current version of the AXXESS System can accommodate vessels from 2.75 to 4.25 mm diameter, and is available in two different lengths (10 and 14 mm). The stent is designed to exert a stable amount of force again the vessel wall over its stated diameter. The distal flare can expand to as much as 8 mm in the largest diameter version. A special version of the AXXESS System has been designed for left main bifurcation lesions, allowing for larger diameters (up to 4.75 mm) and distinct bifurcation angles (flare-end diameters of 8, 10 and 12 mm). The drug-eluting version (AXXESS Plus) is coated with Biolimus A9TM, a highly lipophilic, semi-synthetic sirolimus analogue with an alkoxy-alkyl group replacing hydrogen at position 42-O (Biosensors International, Morges, Switzerland). At a cellular level, biolimus forms a complex with intracellular FKBP-12, which binds to the mammalian target of rapamycin and reversibly inhibits cell-cycle Abbreviations