ASTM F2394-07(2013)
(Guide)Standard Guide for Measuring Securement of Balloon Expandable Vascular Stent Mounted on Delivery System
Standard Guide for Measuring Securement of Balloon Expandable Vascular Stent Mounted on Delivery System
SIGNIFICANCE AND USE
4.1 The securement of the endovascular stent on the balloon is a critical parameter to ensure that the stent is safely delivered to or from the treatment site.
4.2 This guide is intended for use by researchers and manufacturers for the development and selection of pre-test treatments, tests and test endpoints to measure stent securement (displacement distances and dislodgment forces).
4.3 This guide may be used to investigate which practical combinations of in vitro tests best characterize clinical scenarios.
4.4 This guide should be used with discretion in choosing securement tests and evaluating results due to the myriad possible combinations of clinical conditions, failure modes, and stent delivery system designs.
4.5 This guide may be of use for developing a test for meeting parts 2 and 3 of the requirements of EN 14299, Section 7.3.4.4 on Trackability.
4.6 This guide may be of use for developing a test to meet section VII-C-8 of CDRH Guidance document.
SCOPE
1.1 This guide provides guidance for the design and development of pre-test treatments, tests, and test endpoints to measure stent securement of pre-mounted, unsheathed, balloon-expandable stent delivery systems. This guide is intended to aid investigators in the design, development, and in vitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.
1.2 This guide covers the laboratory determination of the shear force required to displace or dislodge a balloon-expandable endovascular stent mounted on a delivery system. The guide proposes a set of options to consider when testing stent securement. The options cover pre-test treatments, possible stent securement tests, and relevant test endpoints. An example test apparatus is given in 7.1.
1.3 This guide covers in vitro bench testing characterization only. Measured levels of securement and product design/process differentiation may be particularly influenced by selections of pre-test treatments, securement test type (for example, stent gripping method), and test endpoint. In vivo characteristics may also differ from in vitro results.
1.4 This guide does not cover all possible pre-test treatments, stent securement tests, or test endpoints. It is intended to provide a starting point from which to select and investigate securement test options.
1.5 This guide does not specify a method for mounting the stent onto the delivery system.
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
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 requirements prior to use.
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Standards Content (Sample)
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Designation: F2394 − 07 (Reapproved 2013)
Standard Guide for
Measuring Securement of Balloon Expandable Vascular
Stent Mounted on Delivery System
This standard is issued under the fixed designation F2394; 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 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This guide provides guidance for the design and devel-
responsibility of the user of this standard to establish appro-
opment of pre-test treatments, tests, and test endpoints to
priate safety and health practices and determine the applica-
measure stent securement of pre-mounted, unsheathed,
bility of regulatory requirements prior to use.
balloon-expandable stent delivery systems. This guide is in-
tended to aid investigators in the design, development, and in
2. Referenced Documents
vitro characterization of pre-mounted, unsheathed, balloon-
2.1 ASTM Standards:
expandable stent delivery systems.
E1169 Practice for Conducting Ruggedness Tests
1.2 This guide covers the laboratory determination of the
E1488 GuideforStatisticalProcedurestoUseinDeveloping
shear force required to displace or dislodge a balloon-
and Applying Test Methods
expandable endovascular stent mounted on a delivery system.
2.2 Other Documents:
The guide proposes a set of options to consider when testing
ISO 10555-1 Sterile Sterile Sterile, Single-use Intravascular
stent securement. The options cover pre-test treatments, pos-
Catheters—Part 1: General Requirements
sible stent securement tests, and relevant test endpoints. An
Quality System Regulation, Part VII Dept. Health and Hu-
example test apparatus is given in 7.1.
man Services, Food and Drug Administration, 21 CFR
Part 820 Medical Devices; Current Good Manufacturing
1.3 This guide covers in vitro bench testing characterization
Practice; Final Rule. Federal Register, October 7, 1996
only. Measured levels of securement and product design/
EN 14299 Non Active Surgical Implants—Particular Re-
process differentiation may be particularly influenced by selec-
quirements for Cardiac and Vascular Implants—Specific
tions of pre-test treatments, securement test type (for example,
Requirements For Arterial Stents, May 2004
stent gripping method), and test endpoint. In vivo characteris-
CDRH Guidance, Non-Clinical Tests and Recommended
tics may also differ from in vitro results.
Labeling for Intravascular Stents andAssociated Delivery
1.4 This guide does not cover all possible pre-test 6
Systems, January 13, 2005
treatments, stent securement tests, or test endpoints. It is
MAUDE Database
intended to provide a starting point from which to select and
investigate securement test options.
3. Terminology
1.5 This guide does not specify a method for mounting the
3.1 Definitions:
stent onto the delivery system.
3.1.1 balloon expandable stent, n—a stent that is expanded
at the treatment site by a balloon catheter. The stent material is
1.6 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
system shall be used independently of the other. Combining
Standards volume information, refer to the standard’s Document Summary page on
values from the two systems may result in non-conformance
the ASTM website.
with the standard.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org.
AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
This guide is under the jurisdiction of ASTM Committee F04 on Medical and www.access.gpo.gov.
Surgical Materials and Devices and is the direct responsibility of Subcommittee Available from British Standards Institute (BSI), 389 Chiswick High Rd.,
F04.30 on Cardiovascular Standards. London W4 4AL, U.K., http://www.bsi-global.com.
Current edition approved March 1, 2013. Published March 2013. Originally Available from Food and Drug Administration (FDA), 5600 Fishers Ln.,
approved in 2004. Last previous edition approved in 2007 as F2394 – 07. DOI: Rockville, MD 20857,. Http://www.fda.gov/cdrh/ode/guidance/1545.pdf.
10.1520/F2394-07R13. Http://www.fda.gov/cdrh/maude.html.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2394 − 07 (2013)
plastically deformed by the balloon expansion such that the 3.1.13 guide-wire, n—a wire designed to aid in balloon,
stent remains expanded after deflation of the balloon. ultrasound, atherectomy, or stent placement during endovascu-
lar procedures.
3.1.2 crimp, v—tosecurethestentonthedeliverysystemby
radially compressing and plastically deforming the stent onto 3.1.14 mandrel, n—awirethatmaybeusedasanalternative
the balloon. to the intended guide-wire to provide support for the catheter
guide-wire lumen for some test procedures.
3.1.3 delivery system, n—a system similar to a balloon
dilatation catheter that is used to deliver and deploy a stent at 3.1.15 non-recoverable movement, n—a displacement of the
the target site and then removed.
stent relative to the balloon such that if the shearing force was
reduced to zero, the stent would remain displaced in the
3.1.4 displacement force, critical distance peak, n—a stent
direction of the shearing force relative to the initial placement
securement test endpoint characterizing the maximum force
on the balloon. The force at which non-recoverable movement
required to displace the stent with respect to the balloon a
begins is defined as the initial displacement force (see defini-
critical distance. This critical distance is the minimum of the
tion above).
following two distances. The first is the distance at which the
undamaged stent could overhang the balloon body resulting in
3.1.16 pre-test treatment, n—a treatment of the stent deliv-
a clinically significant, incomplete end deployment. The sec-
ery system prior to the evaluation of securement that simulates
ond is the length (distance) of stent compression or buckling
preparatory, environmental, mechanical or other conditions
that could result in a clinically significant incomplete deploy-
that may be encountered prior to or during clinical use of the
ment of the stent against the vessel walls. (See Fig. X2.1.)
device. Examples include subjecting the devices to elevated
shipping temperature/humidity, catheter preparation per use
3.1.5 displacement force, initial, n—a stent securement test
instructions, pre-soaking, bending treatments, tracking treat-
endpointcharacterizingtheinitialforcerequiredtodisplacethe
ments (tracking fixture, see definition below) and tracking
stent with respect to the balloon such that the displacement is
through lesion treatments (lesion fixture, see definition below).
a non-recoverable movement (see 3.1.15). (See Fig. X2.1.)
3.1.17 pre-test treatment tracking fixture, n—apre-testtreat-
3.1.6 displacement force, initial peak, n—astentsecurement
mentfixtureusedtosimulateananatomicalvasculature.Useof
test endpoint characterizing the first peak in force that occurs
the fixture with a guide catheter, a guide-wire and the stent-
during or after stent displacement with respect to the balloon.
balloon catheter delivery system is intended to simulate the
(See Fig. X2.1.)
bending and frictional forces of tracking the device to the
3.1.7 dislodgment force, peak, n—a stent securement test
lesion site that may be encountered in the clinical setting. See
endpointcharacterizingthepeakormaximumforcerequiredto
the engineering diagrams in the Appendix. Note that these
completelydislodgethestentfromthedeliverysystemballoon.
engineering diagrams simulate vessels with a moderately
During a test, this force will occur after or coincide with the
difficult degree of coronary tortuousity but do not include
initial displacement force. (See Fig. X2.1.)
simulated lesions.
3.1.8 end flaring, n—a distal or proximal outward conical
3.1.18 pre-test treatment lesion fixture, n—a pre-test treat-
opening of the diameter of the stent on the balloon. End flaring
ment fixture used to simulate an anatomical vasculature and
is a contributing factor to the probability that the stent may
lesion. Use of the fixture with a guide catheter, a guide-wire,
become caught during withdrawal into a guide catheter while
and the stent-balloon catheter delivery system is intended to
tracking through a lesion.
simulate the bending, frictional and mechanical resistance
3.1.9 failure mode effect analysis (FMEA), n—an analytical
forces of tracking the device across the lesion site that may be
approach to methodically determine and address all possible
encountered in the clinical setting.
product failure modes, their associated causes, and their
3.1.19 securement test, guide-type, n—a stent securement
criticality. Used to evaluate designs, prioritize testing, and
test that is similar to the clinical scenario of pulling an
track risk reducing improvements to the product.
undeployed stent delivery system back into a guide catheter,
3.1.10 gauge length, n—the initial unstressed length of
arterial sheath or hemostasis valve. Examples include guides,
catheter tubing between the proximal end of the stent to the
rings,orshimsideallydesignedtoengagethestentendorbody
grips which engage the catheter tubing.
but not the catheter balloon. The shim securement test, de-
scribedinSection7,usescomplementarythin,rigidplateswith
3.1.11 grips, n—a means of applying force to the stent and
rounded “V” notches that are sized to circumferentially engage
balloon catheter to displace or dislodge the stent relative to the
the stent end but not the catheter balloon. See the engineering
balloon. In particular, grips refer to the end of a device which
makes the contact with the stent. Typical grips used to apply diagrams in the Appendix.
force to the stent include shims (as used in Figs. X2.5-X2.8);
3.1.20 securement test, lesion-type, n—a stent securement
tape which sticks to the stent but not the balloon; an iris which
test that is similar to the clinical scenario of pushing or pulling
can be narrowed down to allow the balloon to slip by but not
an undeployed stent delivery system through or around a
the stent; or nubs which contact the stent but not the balloon.
fibrous or calcified lesion. Examples include tape, nubs,
protrusions or sandpaper ideally designed to engage the stent
3.1.12 guide catheter, n—a tube designed to transport the
guide-wire and the stent delivery system into the target vessel. end or body but not the catheter balloon.
F2394 − 07 (2013)
4. Significance and Use guide catheters and stenosis models to in vivo animal studies
with representative anatomy and physician handling. From a
4.1 The securement of the endovascular stent on the balloon
safety-risk perspective, consider how securement challenges
isacriticalparametertoensurethatthestentissafelydelivered
may occur in clinical situations, what may result from loss of
to or from the treatment site.
securement, what the severity of the outcome is to the patient,
4.2 This guide is intended for use by researchers and
what the frequency of these situations are, and then how to test
manufacturers for the development and selection of pre-test
to detect these occurrences. Factors to consider in evaluating
treatments, tests and test endpoints to measure stent secure-
securement tests include the following:
ment (displacement distances and dislodgment forces).
6.2.1.1 Review of the MAUDE database for reported prob-
4.3 This guide may be used to investigate which practical
lems with comparable devices.
combinations of in vitro tests best characterize clinical sce-
6.2.1.2 Physician surveys for clinical relevance and prob-
narios.
lems with comparable devices.
4.4 This guide should be used with discretion in choosing
6.2.1.3 Mechanical understanding of the tests’ clinical rel-
securement tests and evaluating results due to the myriad
evance and limitations.
possible combinations of clinical conditions, failure modes,
6.2.1.4 Mechanical and statistical understanding of the test
and stent delivery system designs.
reproducibility limitations due to device variation, pre-test
4.5 This guide may be of use for developing a test for
treatments, various grips, and test conditions.
meeting parts 2 and 3 of the requirements of EN 14299,
6.2.1.5 Ability to set accept/reject criteria by physician
Section 7.3.4.4 on Trackability.
evaluation, by historical comparisons, or by other rational
means.
4.6 This guide may be of use for developing a test to meet
section VII-C-8 of CDRH Guidance document.
6.2.2 The final securement test(s) selected must ultimately
satisfy internal manufacturer quality standards. These stan-
5. Clinical Scenarios
dards may include clinical relevance, FMEA analysis, statisti-
5.1 There are two failure modes—the stent is dislodged cal assurance of characteristics, and challenge assurance of
from the catheter or the stent is displaced or deformed on the characteristics.
catheter such that balloon inflation delivery would not produce
6.2.3 The final securement test(s) must also satisfy external
an acceptable stent shape at the proper location. Based on
regulatorybodystandards.Forexample,theFDAQSR21CFR
reported clinical incidents, there are three causes for these two
Part 820, Oct. 7, 1996 states that each test used in the process
types of failures:
ofdesignandmanufacturingoffinisheddevices“issuitablefor
5.1.1 Displacement or dislodgment of the stent while at-
its intended purposes and is capable of producing valid
tempting to track through or position in tortuous bends, fibrous
results.” For the statistical capability evaluation, Guide E1488
or calcified lesions, or previously implanted stents, or combi-
is very helpful.
nation thereof.
6.3 Pre-Test Treatments:
5.1.2 Displacement or dislodgment of the stent on with-
drawal of the undeployed stent delivery system back into the 6.3.1 Pre-test treatments may be conducted prior to the
guide catheter, introducer sheath, or hemostasis valve. This evaluation of securement to simulate preparatory,
failure type is usually associated with failure to cross tortuous
environmental, mechanical, or other conditions that may be
bends, fib
...
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