1. Scope
1.1 This guide includes three separate cyclic constant deformation durability guides related to vascular stents: bending, axial, and torsional. 1.2 This guide does not address flat plate, local crush durability, or multi-mode testing. 1.3 This guide is applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this guide to those products is not precluded. 1.4 This guide does not address all issues related to testing for endovascular grafts (stent-grafts) or other conduit products commonly used to treat aneurismal disease, peripheral vessel trauma, or provide vascular access, although the information included herein is applicable to those devices. 1.5 This guide is applicable for determining stent fracture as a result of nonradial arterial motions caused by musculoskeletal deformation (for example, walking, breathing). Test Methods F2477 address pulsatile (that is, radial) durability of vascular stents. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. 1.7 This guide is not intended to provide the in-vivo physiologic loading conditions that a vascular stent is expected to be subjected. Reliable clinical data characterizing cyclic vascular deformation might be lacking for some indications. It is incumbent upon the user of the guide to develop and justify these boundary conditions (for example, literature review, in-vivo studies, cadaver studies, or modeling of stent vessel interaction) in these durability bench tests. Additional conditions that may be considered include: vessel calcification, vessel taper, eccentric lesions, loading excursions (for example, exercise), and vessel remodeling.
Nonradial (axial, bending, torsional) testing is currently required for stents by the FDA for various indications (for example, SFA). There is currently no standardized method and there are multiple methods that folks are using. Medical device manufacturers would use this guide to complete design verification testing of stents. The goal is to have the FDA (CDRH) accept this guide.
Keywords
stent fatigue; stent durability; axial fatigue; bending fatigue; torsional fatigue;, fatigue test; durability test; intravascular device test; vascular stent; stent test; interventional cardiology; endovascular cardiology
The title and scope are in draft form and are under development within this ASTM Committee.
Citing ASTM Standards
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