ASTM F2606-08(2014)
(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.
General Information
Standards Content (Sample)
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Designation: F2606 − 08 (Reapproved 2014)
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 2.1.4 deflection, n—displacement of the dynamic support
(loading anvil) at any point in the test.
1.1 This guide provides guidelines for quantitatively char-
2.1.5 delivery system, n—catheter that is used to deliver and
acterizingballoon-expandablestentandstentsystemflexibility
deploy a stent at the target site. A delivery system for
using three-point bending procedures. Guidelines are provided
balloon-expandable stents may be similar to a balloon-
for characterizing deployed stent flexibility, and for character-
dilatation (angioplasty) catheter.
izing pre-deployment stent system flexibility in the region of
the stent and balloon.
2.1.6 midspan bending moment, n—a linear estimate of the
bending moment at the center of the span. See 8.5.
1.2 This guide is not recommended for test articles that
cannot be appropriately evaluated using a span length to stent
2.1.7 midspan curvature, n—a linear estimate of the curva-
outer diameter (as tested) ratio of at least 4:1. Test articles that
ture of the center of the span. See 8.5.
do not meet this requirement are likely to exhibit appreciable
2.1.8 span length, n—distance between the centers of the
deformation by modes other than bending.
supports.
1.3 This guide does not provide procedures for characteriz-
2.1.9 stent system, n—delivery system with a pre-mounted
ing the bending flexibility of self-expanding stents, self-
stent.
expanding stent systems, endoprostheses (stent-grafts), or en-
2.1.10 stent, vascular, n—synthetic structure that is perma-
doprostheses systems. However, some aspects of this guide
nentlyimplantedinthenativeorgraftedvasculatureandthatis
may be useful for developing appropriate three-point bending
intended to provide mechanical radial support to enhance
characterization procedures for these devices.While this guide
vessel patency.
was developed with vascular stents and stent systems in mind,
it may be useful for characterizing the bending flexibility of
3. Significance and Use
balloon-expandable stents and stent systems used in non-
3.1 This guide can be used to obtain force versus deflection
vascular applications.
or midspan bending moment versus midspan curvature curves
1.4 The values stated in SI units are to be regarded as the
for stents and stent systems subjected to three-point bending
standard. The values given in parentheses are mathematical
conditions. Bending flexibility of a stent system may be a
conversions to inch-pound units that are provided for informa-
factor in its ability to track through the vascular anatomy, and
tion only and are not considered standard.
may be a factor in vascular trauma along the delivery pathway
distal to the guide catheter. Bending flexibility of a deployed
2. Terminology
stent may be one measure of its ability to flex with a vessel, or
2.1 Definitions:
to conform to the natural curvature of a vessel. Bending
2.1.1 bending flexibility, n—ameasureoftheabilityofatest
flexibility of a delivery system may also be of interest if it is
specimen to bend.
desired to assess the separate contributions of the delivery
2.1.2 bending stiffness, n—a measure of the ability of a test system and the mounted stent to the overall flexibility of the
stent system.
specimen to resist bending.
2.1.3 conformability, n—the degree to which a stent or stent
3.2 This guide is not intended to determine material
system matches the native curvature of the vasculature. properties,stentsystemtrackability(abilityofastentsystemto
follow a guide wire and/or guide catheter through vascular
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tortuosity), or stent system deliverability (ability of a stent
This guide is under the jurisdiction ofASTM Committee F04 on Medical and
Surgical Materials and Devices and is the direct responsibility of Subcommittee
system to deliver a stent to the implantation site(s) or through
F04.30 on Cardiovascular Standards.
particularlevel(s)ofvasculartortuosity).Whilethisguidedoes
Current edition approved March 1, 2014. Published April 2014. Originally
not determine stent system trackability or deliverability, it can
approved in 2008. Last previous edition approved in 2008 as F2606 – 08. DOI:
10.1520/F2606-08R14. provide quantitative insight into how stent system bending
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