ASTM F2477-07
(Test Method)Standard Test Methods for in vitro Pulsatile Durability Testing of Vascular Stents
Standard Test Methods for <i>in vitro</i> Pulsatile Durability Testing of Vascular Stents
ABSTRACT
This test method covers the procedure for determining the durability of ballon-expandable and self- expanding metal or alloy vascular stents. Tests are performed by exposing specimens to physiologically relevant diametric distention levels using hydrodynamic pulsatile loading. Specimens should have been deployed into a mock or elastically simulated vessel prior to testing. The test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distention and include physiological pressure tests and diameter control tests. These do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion. Test apparatus include a pressure measurement system, dimensional measurement devices, a cycle counting system, and a temperature control system.
SCOPE
1.1 These test methods cover the determination of the durability of a vascular stent by exposing it to physiologically relevant diametric distension levels by means of hydrodynamic pulsatile loading. This testing occurs on a stent test specimen that has been deployed into a mock (elastically simulated) vessel. The typical duration of this test is 10 years of equivalent use (at 72 beats per minute), or at least 380 million cycles.
1.2 These test methods are applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this test method to those products is not precluded.
1.3 These test methods do not include recommendations for endovascular grafts ("stent-grafts") or other conduit products commonly used to treat aneurismal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.
1.4 These test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distension. These test methods do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion.
1.5 These test methods do not address test conditions for curved mock vessels.
1.6 These test methods do not address test conditions for overlapping stents.
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 and health practices and determine the applicability of regulatory limitations prior to use.
1.8 General Caveat—This document contains guidance for testing as is currently carried out in most laboratories. Other testing techniques may prove to be more effective and are encouraged. Whichever technique is used, it is incumbent upon the tester to justify the use of the particular technique, instrument, and protocol. This includes the choice of and proper calibration of all measuring devices. Deviations from any of the suggestions in this document may be appropriate but may require the same level of comprehensive justification that the techniques described herein will require.
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Designation: F2477 − 07
StandardTest Methods for
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in vitro Pulsatile Durability Testing of Vascular Stents
This standard is issued under the fixed designation F2477; 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 encouraged. Whichever technique is used, it is incumbent upon
the tester to justify the use of the particular technique,
1.1 These test methods cover the determination of the
instrument, and protocol. This includes the choice of and
durability of a vascular stent by exposing it to physiologically
proper calibration of all measuring devices. Deviations from
relevantdiametricdistensionlevelsbymeansofhydrodynamic
any of the suggestions in this document may be appropriate but
pulsatile loading. This testing occurs on a stent test specimen
may require the same level of comprehensive justification that
that has been deployed into a mock (elastically simulated)
the techniques described herein will require.
vessel.Thetypicaldurationofthistestis10yearsofequivalent
use (at 72 beats per minute), or at least 380 million cycles.
2. Referenced Documents
1.2 Thesetestmethodsareapplicabletoballoon-expandable
and self-expanding stents fabricated from metals and metal
2.1 Other Documents:
alloys. It does not specifically address any attributes unique to ISO 7198: 1998(e), 8.10, Determination of Dynamic Com-
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coated stents, polymeric stents, or biodegradable stents, al-
pliance
though the application of this test method to those products is FDA Guidance Document 1545, Non-Clinical Tests and
not precluded.
Recommended Labeling for Intravascular Stents and As-
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sociated Delivery Systems, (issued January 13, 2005)
1.3 These test methods do not include recommendations for
endovascular grafts (“stent-grafts”) or other conduit products
3. Terminology
commonly used to treat aneurismal disease or peripheral vessel
trauma or to provide vascular access, although some informa-
3.1 Definitions of Terms Specific to This Standard:
tion included herein may be applicable to those devices.
3.1.1 cardiac cycle, n—defined as one cycle between dia-
stolic and systolic pressures.
1.4 These test methods are valid for determining stent
failure due to typical cyclic blood vessel diametric distension.
3.1.2 compliance, n—the change in inner diameter of a
These test methods do not address other modes of failure such
vessel due to cyclic pressure changes. Compliance, if
as dynamic bending, torsion, extension, crushing, or abrasion.
calculated, shall be expressed as a percentage of the diameter
change per 100 mm Hg and defined per ISO 7198, 8.10.5:
1.5 These test methods do not address test conditions for
curved mock vessels. 4
~Dp2 2 Dp1! 310
%Compliance/100 mm Hg 5 (1)
Dp1 p2 2 p1
~ ~ !!
1.6 These test methods do not address test conditions for
overlapping stents.
where:
1.7 This standard does not purport to address all of the
Dp1 = inner diameter at the pressure of p1,
safety concerns, if any, associated with its use. It is the
Dp2 = inner diameter at the pressure of p2,
responsibility of the user of this standard to establish appro-
p1 = lower pressure value (diastolic), in mm Hg, and
priate safety and health practices and determine the applica-
p2 = higher pressure value (systolic), in mm Hg.
bility of regulatory limitations prior to use.
3.1.3 diametric strain, n—a change in mock artery diameter
1.8 General Caveat—This document contains guidance for
divided by the initial diameter. This term does not relate to the
testing as is currently carried out in most laboratories. Other
mechanical strain seen in the stent material. The diametric
testing techniques may prove to be more effective and are
strain can be identified as:
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These test methods are under the jurisdiction of ASTM Committee F04 on
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Medical and Surgical Materials and Devices and is the direct responsibility of Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
Subcommittee F04.30 on Cardiovascular Standards. 4th Floor, New York, NY 10036, http://www.ansi.org.
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Current edition approved April 1, 2007. Published May 2007. Originally Available from Food and Drug Administration (FDA), 5600 Fishers Ln.,
approved in 2006. Last previous edition approved in 2006 as F2477 – 06. DOI: Rockville, MD 20857, http://www.fda.gov. This document available at http://
10.1520/F2477-07. www.fda.gov/cdrh/ode/guidance/1545.pdf.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F2477 − 07
Dp2 2 Dp1 5. Specimen Size, Configuration, and Pr
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