ASTM F3067-14(2021)
(Guide)Standard Guide for Radial Loading of Balloon-Expandable and Self-Expanding Vascular Stents
Standard Guide for Radial Loading of Balloon-Expandable and Self-Expanding Vascular Stents
SIGNIFICANCE AND USE
4.1 Upon deployment, at the site of the vascular stenosis, the stent establishes the patency of the lumen until vascular remodeling occurs. The radial load acting upon the stent is imparted by vessel and lesion stretch. Additionally, the vessel might be affected by excursions due to pulsation (systolic and diastolic variation), muscle-skeletal interactions due to patient movement, as well as external sources (e.g., patient is struck in the neck during a car accident). The excursions vary in magnitude and type based on the location of the vessel.
4.2 In order to maintain vessel patency, the stent has to withstand the forces acting on it without experiencing excessive deformation, migration, or sustained collapse; therefore, it is required that the stent possess adequate resistance to these loads.
4.3 Depending on the type of device and the clinical concern, the resistance to these loads can be presented through multiple test outputs: radial strength, collapse pressure, or chronic outward force.
4.4 The guidelines presented here can be used in the development of test methods to determine the radial loading properties of stents. This guide provides examples of different test apparatus (equipment and tooling), radial loading curves, and calculations. Although the apparatus and methods presented can be used as a reasonable simulation of actual clinical use, they have not been demonstrated to predict the actual in vivo clinical performance of any stent.
SCOPE
1.1 This document provides guidance for developing in vitro test methods for measuring the radial strength or collapse pressure of balloon-expandable vascular stents and chronic outward force of self-expanding vascular stents.
1.2 This guide is applicable to balloon-expandable and self-expanding stents of tubular geometry. It covers both stent and stent grafts. It does not cover bifurcated stents. It does not cover stents with non-circular cross sections or tapered stents.
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This guide does not recommend any specific test method or apparatus for measuring the radial strength, collapse pressure, or chronic outward force. Instead, this guide provides examples of test methodologies and equipment that could be used and recommends the format for presenting test results.
1.5 This guide covers only in vitro bench testing methods. In vivo behavior might be different.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 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: F3067 − 14 (Reapproved 2021)
Standard Guide for
Radial Loading of Balloon-Expandable and Self-Expanding
1
Vascular Stents
This standard is issued under the fixed designation F3067; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This document provides guidance for developing in
E4 Practices for Force Verification of Testing Machines
vitro test methods for measuring the radial strength or collapse
E177 Practice for Use of the Terms Precision and Bias in
pressure of balloon-expandable vascular stents and chronic
ASTM Test Methods
outward force of self-expanding vascular stents.
F2079 Test Method for Measuring Intrinsic Elastic Recoil of
1.2 This guide is applicable to balloon-expandable and
Balloon-Expandable Stents
self-expanding stents of tubular geometry. It covers both stent
F2081 Guide for Characterization and Presentation of the
and stent grafts. It does not cover bifurcated stents. It does not
Dimensional Attributes of Vascular Stents
cover stents with non-circular cross sections or tapered stents.
F2477 Test Methods for in vitro Pulsatile Durability Testing
of Vascular Stents
1.3 Units—The values stated in SI units are to be regarded
as standard. No other units of measurement are included in this
3. Terminology
standard.
3.1 Definitions:
1.4 Thisguidedoesnotrecommendanyspecifictestmethod
3.1.1 balloon-expandable stent—a stent that is expanded at
or apparatus for measuring the radial strength, collapse
the treatment site by a balloon catheter. The stent material is
pressure, or chronic outward force. Instead, this guide provides
plastically deformed by the balloon expansion such that the
examples of test methodologies and equipment that could be
stent remains expanded after deflation of the balloon.
used and recommends the format for presenting test results.
3.1.2 chronic outward force—the minimum continued open-
ing force of a self-expanding stent acting on the vessel wall at
1.5 This guide covers only in vitro bench testing methods.
a specified diameter. The range of chronic outward force is
In vivo behavior might be different.
defined by the unloading curve at the maximum and minimum
1.6 This standard does not purport to address all of the
indicated use diameters. Additional loading force consider-
safety concerns, if any, associated with its use. It is the
ations for self-expanding stents are evaluated as load excur-
responsibility of the user of this standard to establish appro-
sions and described in Appendix X2. Chronic outward force is
priate safety, health, and environmental practices and deter-
not defined for balloon-expandable stents.
mine the applicability of regulatory limitations prior to use.
3.1.3 collapse pressure—the uniform radial load during
1.7 This international standard was developed in accor-
testing with a hydraulic or pneumatic apparatus in which a
dance with internationally recognized principles on standard-
balloon-expandable stent undergoes buckling over a specific
ization established in the Decision on Principles for the
region or the entire stent length.
Development of International Standards, Guides and Recom-
3.1.4 load—a normalized, scalar value of force applied by
mendations issued by the World Trade Organization Technical
the stent to the vessel and, at equilibrium, the vessel upon the
Barriers to Trade (TBT) Committee.
stent. Load should be normalized by length (newton or
millinewton per millimeter length) or by area (pascal or
kilopascal).
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This guide is under the jurisdiction of ASTM Committee F04 on Medical and
Surgical Materials and Devices and is the direct responsibility of Subcommittee
2
F04.30 on Cardiovascular Standards. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Aug. 1, 2021. Published August 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2014. Last previous edition approved in 2014 as F3067 – 14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/F3067-14R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F3067 − 14 (2021)
3.1.5 loading line—for balloon-expandable stents, the line shape that is close to the desired final size and shape
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