ASTM F2606-08(2021)
(Guide)Standard Guide for Three-Point Bending of Balloon-Expandable Vascular Stents and Stent Systems
Standard Guide for Three-Point Bending of Balloon-Expandable Vascular Stents and Stent Systems
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 nation...
SCOPE
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.
General Information
Standards Content (Sample)
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.
Designation: F2606 − 08 (Reapproved 2021)
Standard Guide for
Three-Point Bending of Balloon-Expandable Vascular Stents
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and Stent Systems
This standard is issued under the fixed designation F2606; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.1.1 bending flexibility, n—ameasureoftheabilityofatest
specimen to bend.
1.1 This guide provides guidelines for quantitatively char-
acterizingballoon-expandablestentandstentsystemflexibility 2.1.2 bending stiffness, n—a measure of the ability of a test
using three-point bending procedures. Guidelines are provided
specimen to resist bending.
for characterizing deployed stent flexibility, and for character-
2.1.3 conformability, n—the degree to which a stent or stent
izing pre-deployment stent system flexibility in the region of
system matches the native curvature of the vasculature.
the stent and balloon.
2.1.4 deflection, n—displacement of the dynamic support
1.2 This guide is not recommended for test articles that
(loading anvil) at any point in the test.
cannot be appropriately evaluated using a span length to stent
2.1.5 delivery system, n—catheter that is used to deliver and
outer diameter (as tested) ratio of at least 4:1. Test articles that
deploy a stent at the target site. A delivery system for
do not meet this requirement are likely to exhibit appreciable
balloon-expandable stents may be similar to a balloon-
deformation by modes other than bending.
dilatation (angioplasty) catheter.
1.3 This guide does not provide procedures for characteriz-
2.1.6 midspan bending moment, n—a linear estimate of the
ing the bending flexibility of self-expanding stents, self-
bending moment at the center of the span. See 8.5.
expanding stent systems, endoprostheses (stent-grafts), or en-
doprostheses systems. However, some aspects of this guide
2.1.7 midspan curvature, n—a linear estimate of the curva-
may be useful for developing appropriate three-point bending
ture of the center of the span. See 8.5.
characterization procedures for these devices.While this guide
2.1.8 span length, n—distance between the centers of the
was developed with vascular stents and stent systems in mind,
supports.
it may be useful for characterizing the bending flexibility of
balloon-expandable stents and stent systems used in non- 2.1.9 stent system, n—delivery system with a pre-mounted
vascular applications. stent.
1.4 The values stated in SI units are to be regarded as the
2.1.10 stent, vascular, n—synthetic structure that is perma-
standard. The values given in parentheses are mathematical nentlyimplantedinthenativeorgraftedvasculatureandthatis
conversions to inch-pound units that are provided for informa-
intended to provide mechanical radial support to enhance
tion only and are not considered standard. vessel patency.
1.5 This international standard was developed in accor-
3. Significance and Use
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
3.1 This guide can be used to obtain force versus deflection
Development of International Standards, Guides and Recom-
or midspan bending moment versus midspan curvature curves
mendations issued by the World Trade Organization Technical
for stents and stent systems subjected to three-point bending
Barriers to Trade (TBT) Committee.
conditions. Bending flexibility of a stent system may be a
factor in its ability to track through the vascular anatomy, and
2. Terminology
may be a factor in vascular trauma along the delivery pathway
2.1 Definitions:
distal to the guide catheter. Bending flexibility of a deployed
stent may be one measure of its ability to flex with a vessel, or
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to conform to the natural curvature of a vessel. Bending
This guide is under the jurisdiction ofASTM Committee F04 on Medical and
Surgical Materials and Devices and is the direct responsibility of Subcommittee
flexibility of a delivery system may also be of interest if it is
F04.30 on Cardiovascular Standards.
desired to assess the separate contributions of the delivery
Current edition approved Aug. 1, 2021. Published August 2021. Originally
system and the mounted stent to the overall flexibility of the
approved in 2008. Last previous edition approved in 2014 as F2606 – 08 (2014).
DOI: 10.1520/F2606-08R21. stent system.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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