【国外标准】 Standard Guide for Measuring Securement of Balloon-Expandable Vascular Stent Mounted on Delivery System

4.1 The securement of the endovascular stent on the balloon is a critical parameter to ensure that the stent is safely delivered to or from the treatment site.4.2 This guide is intended for use by researchers and manufacturers for the development and selection of pre-test treatments, tests, and test endpoints to measure stent securement (displacement distances and dislodgment forces).4.3 This guide may be used to investigate which practical combinations of in vitro tests best characterize clinical scenarios.4.4 This guide should be used with discretion in choosing securement tests and evaluating results due to the myriad possible combinations of clinical conditions, failure modes, and stent delivery system designs.4.5 This guide may be of use for developing a test for meeting Parts 2 and 3 of the requirements of EN 14299, Section 7.3.4.4 on Trackability.4.6 This guide may be of use for developing a test to meet section VII-C-8 of CDRH Guidance document.1.1 This guide provides guidance for the design and development of pre-test treatments, tests, and test endpoints to measure stent securement of pre-mounted, unsheathed, balloon-expandable stent delivery systems. This guide is intended to aid investigators in the design, development, and in vitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.1.2 This guide covers the laboratory determination of the shear force required to displace or dislodge a balloon-expandable endovascular stent mounted on a delivery system. The guide proposes a set of options to consider when testing stent securement. The options cover pre-test treatments, possible stent securement tests, and relevant test endpoints. An example test apparatus is given in 7.1.1.3 This guide covers in vitro bench testing characterization only. Measured levels of securement and product design/process differentiation may be particularly influenced by selections of pre-test treatments, securement test type (for example, stent gripping method), and test endpoint. In vivo characteristics may also differ from in vitro results.1.4 This guide does not cover all possible pre-test treatments, stent securement tests, or test endpoints. It is intended to provide a starting point from which to select and investigate securement test options.1.5 This guide does not specify a method for mounting the stent onto the delivery system.1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.1.7 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 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.