ASTM F2081-06(2022)

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: F2081 − 06 (Reapproved 2022)
Standard Guide for
Characterization and Presentation of the Dimensional
Attributes of Vascular Stents
This standard is issued under the fixed designation F2081; 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 1.6 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
1.1 This guide covers the identification of and recom-
each system are not necessarily exact equivalents; therefore, to
mended measurement methods for those dimensional attributes
ensure conformance with the standard, each system shall be
of vascular stents that are deemed relevant to successful
used independently of the other, and values from the two
clinical performance. The delivery system packaged with and
systems shall not be combined.
labeled specifically for use during the placement of the stent is
1.6.1 The units of measurements used throughout this guide
also included within the scope of this guide.
reflect the hybrid system in common clinical use in the United
1.2 This guide addresses only the dimensional characteris-
States as of the time of the original approval of this guide.
tics of stents. Material property and stent functional character-
Since a primary purpose of this guide is to promote uniformity
istics are not addressed herein. All dimensional characteristics
of labeling to facilitate the selection of devices by clinical
described in this guide refer to in vitro (“bench-top”) charac-
users, the units most preferred by users were selected for this
terization. Because of variable patient factors, for example,
guide. Where those units are not SI units, or derivatives
vessel compliance, the actual in vivo characteristics may be
thereof, SI units are provided in parentheses.
slightly different.
1.7 This international standard was developed in accor-
1.3 This guide includes recommendations generally appli-
dance with internationally recognized principles on standard-
cable to balloon-expandable and self-expanding stents fabri-
ization established in the Decision on Principles for the
cated from metals and metal alloys. It does not specifically
Development of International Standards, Guides and Recom-
address any attributes unique to coated stents or polymeric or
mendations issued by the World Trade Organization Technical
biodegradable stents, although the application of this guide to
Barriers to Trade (TBT) Committee.
those products is not precluded.
2. Referenced Documents
1.4 Whiletheyarenotspecificallyincludedwithinthescope
of this guide, stents indicated for placement in nonvascular
2.1 ISO Standards:
locations, such as the esophagus or bile duct, also might be
ISO 10555-1 Sterile, Single-Use Intravascular Catheters—
characterized by the methods contained herein. Likewise, this
General Requirements
guide does not include recommendations for endovascular
ISO 10555-4 Sterile, Single-Use Intravascular Catheters—
grafts (“stent-grafts”) or other conduit devices commonly used
Balloon Dilation Catheters
to treat aneurysmal disease or peripheral vessel trauma or to
provide vascular access, although some information included
3. Terminology
herein may be applicable to those devices.
3.1 Definitions of Terms Specific to This Standard:
1.5 This guide does not include recommendations for bal-
3.1.1 balloon-expandable stent, n—a stent that is expanded
loon catheters sold as stand-alone angioplasty catheters, even
at the treatment site by a balloon catheter. The stent is altered
though some of those catheters may be used for the delivery of
permanently by the balloon expansion such that the stent
unmounted stents supplied without a delivery system. Require-
remains expanded after deflation of the balloon.
ments for angioplasty catheters are contained in standards ISO
3.1.2 bridge, n—a connecting element between the radial
10555-1 and ISO 10555-4.
support aspects of a stent. A bridge may have unique design
features, as compared to a strut, to enhance longitudinal
This guide is under the jurisdiction of ASTM Committee F04 on Medical and
flexibility and minimize shortening.
Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.30 on Cardiovascular Standards.
Current edition approved Oct. 1, 2022. Published October 2022. Originally
approved in 2001. Last previous edition approved in 2017 as F2081 – 06 (2017). Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
DOI: 10.1520/F2081-06R22. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2081 − 06 (2022)
3.1.3 crimp, v—tosecurethestentonthedeliverysystemby selection of devices for individual patients.This guide contains
compressing the stent onto the balloon. Stents sold unmounted a listing of those dimensional attributes that are directly related
must be crimped manually by the clinical staff before use. to the clinical utility and performance of these devices, along
with recommendations for consistent methods of measuring
3.1.4 crossing profile, n—a linear measure of the maximum
these attributes and presenting the information for use in
breadth of the stent/delivery system over the distal-most region
clinical decision making. This guide can be used by the
of the delivery system.
manufacturers and researchers of stents to provide consistency
3.1.5 delivery system,n—asystemthatisusedtodeliverand
of measurement and labeling of these dimensional character-
deploy a stent at the target site. A delivery system may be
istics. It may have use in the regulation of these devices by
similar to a balloon dilation catheter; a delivery system for a
appropriate authorities.
self-expanding stent might not have a balloon.
4.2 The dimensional attributes included in this guide are
3.1.6 diameter, n—refers to the inside diameter (ID) of the
those that are deemed related to or possibly predictive of
stent unless otherwise noted.
successful clinical performance of the stent based on prior
3.1.7 diameter, labeled, n—single value representation of
clinicalexperience;however,becauseofthemyriadpatientand
intended-usediameters,typicallyroundedtothenearest0.25or
medical factors that influence the clinical outcome of any
0.5 mm. The labeled diameter is within the range recom-
individual treatment, conformance of a stent and delivery
mended in the Instructions for Use (IFU) for that particular
system with the recommendations in this guide should not be
stent and delivery system.
interpreted as a guarantee of clinical success in any individual
patient or group of patients.
3.1.8 percent solid area, n—that percentage of the projected
cylindrical side surface area (π times outside diameter times
5. Classification
length at labeled diameter) that is covered by stent material,
when the stent is expanded to its labeled diameter.
5.1 Stentsmaybeclassifiedbythefollowingcharacteristics,
as defined in Section 3.
3.1.9 premounted stent, n—a stent supplied by a manufac-
5.1.1 Mounting—Premounted or unmounted.
turer already mounted on a delivery system.
5.1.2 Expansion—Balloon expandable or self-expanding.
3.1.10 self-expanding stent, n—a stent that expands without
extrinsic force or pressure, to a size and shape close to the
6. Test Devices and General Procedures
desired final size and shape, when released from the delivery
6.1 Unless otherwise justified, all samples selected for
system. The self-expanding nature of some stents is a design
testing or measuring the attributes described in this guide
feature resulting from the materials of construction or the
should be taken from finished, clinical-quality product. Cos-
structural geometry, or both.
metic rejects or other nonclinical samples may be used if the
3.1.11 sheath, n—a movable cover that constrains a self-
cause for rejection is not related to the attribute being assessed.
expanding stent on the delivery system until its desired release
Sterilization can be omitted if it can be demonstrated that
or protects a balloon-expandable stent during delivery before
sterilization has no affect on the attribute being assessed.
deployment.
6.2 When specimen preparation (for example, manual
3.1.12 shortening/lengthening, n—the percentage change in
crimping onto a delivery system, balloon expansion) is re-
length between the undeployed mounted condition and the
quired before testing, this should be done in accordance with
expanded labeled-diameter condition.
the Instructions for Use (IFU).
3.1.13 stent, vascular, n—asynthetictubularstructurethatis
6.3 The preconditioning and test environments must be
permanently implanted in the native or grafted vasculature and
appropriately selected for each design and attribute. Tempera-
that is intended to provide mechanical radial support to
ture and fluid immersion may have a significant effect on some
enhance vessel patency. For the purposes of this guide, a stent
attributes but a negligible effect on others. For example, fluid
is metallic and not covered by synthetic textile or tissue graft
sorption may swell catheters and affect the measurement of
material.
crossing profile. Temperature may affect the final deployed
3.1.14 strut, n—the smallest individual element of the radial
diameter for stents made from shape memory materials. For
support aspect of a stent that has a solid cross section in both
measurements for which deployment or measurement, or both,
the radial and circumferential directions.
is to be made in a controlled environment, the stent or delivery
3.1.15 unmounted stent, n—a stent that is not crimped on a
system, or both, should be immersed in a water bath main-
delivery system as supplied by the manufacturer. Before use,
tained at 37 6 2 °C and allowed to equilibrate.
the clinical staff must manually crimp unmounted stents onto a
6.4 The number of specimens evaluated for each diameter
delivery device.
for each stent design should be sufficient to meet the sampling
requirementsforthedesiredlabeling.Ingeneral,aminimumof
4. Significance and Use
ten replicate test devices of each size to be measured or tested
4.1 Vascular stents are intended for permanent implant in is recommended. If a single stent design is intended to be
the human vasculature (native or graft) for the purposes of deployed over a broad range of diameters by use on different
maintaining vessel patency. The dimensional attributes of size delivery systems, the dimensional attributes should be
vascular stents are critical parameters that aid clinicians in the evaluated for each stent/delivery system combination.
F2081 − 06 (2022)
7. Dimensions and Measurement Methods and the expanded labeled-diameter condition. Shortening/
lengthening should be reported as a percentage of the mounted
7.1 Deployed Diameter—Unless otherwise specified, all
(undeployed) length to the nearest 1 %.
deployed diameters refer to the inside diameter, reported in
millimetres to the nearest 0.1 mm, after balloon deflation (for
7.3 Crossing Profile:
balloon-expandable stents).
7.3.1 Measurement—With the stent premounted or hand-
7.1.1 Measurement—The outside diameter of deployed
crimped on the delivery system in accordan
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