1.1 本指南提供了使用三点弯曲程序定量表征球囊可膨胀支架和支架系统灵活性的指南。本指南用于表征已部署支架的灵活性，以及表征支架和球囊区域内预部署支架系统的灵活性。 1.2 对于不能使用跨度长度与支架外径（测试时）之比至少为4:1进行适当评估的供试品，不建议使用本指南。不符合此要求的试件可能通过弯曲以外的模式表现出明显的变形。 1.3 本指南不提供表征自身弯曲灵活性的程序- 扩张支架、自扩张支架系统、内支架（支架移植物）或内支架系统。然而，本指南的某些方面可能有助于为这些设备开发适当的三点弯曲表征程序。虽然本指南是在考虑血管支架和支架系统的情况下制定的，但它可能有助于表征非血管应用中使用的球囊可膨胀支架和支架系统的弯曲灵活性。 1.4 以国际单位制表示的数值应视为标准。括号中给出的值是英寸-磅单位的数学转换，仅供参考，不被视为标准值。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 3.1 本指南可用于获得承受三点弯曲条件的支架和支架系统的力-挠度或跨中弯矩-跨中曲率曲线。支架系统的弯曲灵活性可能是其跟踪血管解剖结构能力的一个因素，也可能是导向导管远端输送路径沿线血管损伤的一个因素。 已部署支架的弯曲灵活性可能是衡量其与血管弯曲或符合血管自然曲率能力的一个指标。如果需要评估输送系统和已安装支架对支架系统整体灵活性的单独贡献，则输送系统的弯曲灵活性也可能值得关注。 3.2 本指南不旨在确定材料特性、支架系统可追踪性（支架系统跟随导丝和/或引导导管通过血管迂曲的能力）或支架系统可交付性（支架系统将支架交付至植入部位或通过特定水平的血管迂曲的能力）。 虽然本指南并不确定支架系统的可追踪性或可交付性，但它可以定量了解支架系统弯曲灵活性如何影响可追踪性和可交付性。同样，虽然本指南并不确定已部署支架的适形性，但它可以定量了解支架和/或支架系统弯曲灵活性如何影响已部署支架的适形性。由于本指南量化了弯曲柔性，因此在确定弯曲柔性对供试品和控制装置之间弯曲相关性能差异的影响程度时可能有用。 3.3 本指南中提供的三点弯曲程序旨在用于表征气球的特性- 可膨胀支架和支架系统在产品开发过程中的灵活性。它们可能不一定满足国家或国际监管机构的任何特定要求。

1.1 This guide provides guidelines for quantitatively characterizing balloon-expandable stent and stent system flexibility using three-point bending procedures. Guidelines are provided for characterizing deployed stent flexibility, and for characterizing pre-deployment stent system flexibility in the region of the stent and balloon. 1.2 This guide is not recommended for test articles that cannot be appropriately evaluated using a span length to stent outer diameter (as tested) ratio of at least 4:1. Test articles that do not meet this requirement are likely to exhibit appreciable deformation by modes other than bending. 1.3 This guide does not provide procedures for characterizing the bending flexibility of self-expanding stents, self-expanding stent systems, endoprostheses (stent-grafts), or endoprostheses systems. However, some aspects of this guide may be useful for developing appropriate three-point bending characterization procedures for these devices. While this guide was developed with vascular stents and stent systems in mind, it may be useful for characterizing the bending flexibility of balloon-expandable stents and stent systems used in non-vascular applications. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 3.1 This guide can be used to obtain force versus deflection or midspan bending moment versus midspan curvature curves for stents and stent systems subjected to three-point bending conditions. Bending flexibility of a stent system may be a factor in its ability to track through the vascular anatomy, and may be a factor in vascular trauma along the delivery pathway distal to the guide catheter. Bending flexibility of a deployed stent may be one measure of its ability to flex with a vessel, or to conform to the natural curvature of a vessel. Bending flexibility of a delivery system may also be of interest if it is desired to assess the separate contributions of the delivery system and the mounted stent to the overall flexibility of the stent system. 3.2 This guide is not intended to determine material properties, stent system trackability (ability of a stent system to follow a guide wire and/or guide catheter through vascular tortuosity), or stent system deliverability (ability of a stent system to deliver a stent to the implantation site(s) or through particular level(s) of vascular tortuosity). While this guide does not determine stent system trackability or deliverability, it can provide quantitative insight into how stent system bending flexibility affects trackability and deliverability. Similarly, while this guide does not determine conformability of a deployed stent, it can provide quantitative insight into how stent and/or stent system bending flexibility affects deployed stent conformability. Since this guide quantifies bending flexibility, it may be useful in determining the magnitude of bending flexibility effects on bending-related performance differences between the test article and control devices. 3.3 The three-point bending procedures provided in this guide are intended to be used to characterize balloon-expandable stent and stent system flexibility during product development. They may not necessarily satisfy any particular requirements of national or international regulatory bodies.