Guidance for Industry and FDA Staff 
Non-Clinical Engineering Tests and 
Recommended Labeling for 
Intravascular Stents and Associated 
Delivery Systems 
Document issued on: April 18, 2010 
On August 18, 2015 FDA issued a guidance Select Updates for Non-Clinical Engineering 
Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems. 
That guidance document updates and augments (but does not replace) this guidance. 
This document supersedes the guidance Non-Clinical Engineering Tests and Recommended Labeling for 
Intravascular Stents and Associated Delivery Systems dated January 13, 2005.  
For questions regarding this document, contact the Interventional Cardiology Devices Branch at or the 
Peripheral Interventional Devices Branch at (301) 796-7000. 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Devices and Radiological Health 
Interventional Cardiology Devices Branch 
Peripheral Vascular Devices Branch 
Division of Cardiovascular Devices 
Office of Device Evaluation  Contains Nonbinding Recommendations 
 
Preface 
 
Public Comment 
 
Comments and suggestions may be submitted at any time for Agency consideration to Dockets 
Management Branch, Division of Management Systems and Policy, Office of Human Resources 
and Management Services, Food and Drug Administration, 5630 Fishers Lane, Room 1061, 
(HFA-305), Rockville, MD, 20852.  When submitting comments, please refer to the exact title of 
this guidance document. Comments may not be acted upon by the Agency until the document is 
next revised or updated. 
 
Additional Copies 
 
Additional copies are available from the Internet at:  
http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm0
71863.htm.  You may also send an e-mail request to dsmica@fda.hhs.gov to receive an 
electronic copy of the guidance or send a fax request to 240-276-3151 to receive a hard copy.  
Please use the document number (1545) to identify the guidance you are requesting. 
  Contains Nonbinding Recommendations 
 
Table of Contents 
I.  INTRODUCTION.............................................................................................................1 
II.  SCOPE...............................................................................................................................2 
III.  CONTENT AND FORMAT OF TEST DATA..............................................................4 
A.  Summary Reports..........................................................................................................................4 
B.  Test Reports....................................................................................................................................5 
C.  Test Protocols.................................................................................................................................6 
IV.  NON-CLINICAL ENGINEERING TESTS...................................................................8 
A.  Material Characterization.............................................................................................................8 
1.  Material Composition......................................................................................................................8 
2.  Shape Memory and Superelasticity of Intravascular Stents.............................................................9 
3.  Stent Corrosion Resistance..............................................................................................................9 
B.  Stent Dimensional and Functional Attributes...........................................................................11 
1.  Dimensional Verification...............................................................................................................11 
2.  Percent Surface Area......................................................................................................................12 
3.  Foreshortening...............................................................................................................................12 
4.  Recoil for Balloon Expandable Stents...........................................................................................13 
5.  Stent Integrity................................................................................................................................13 
6.  Radial Stiffness and Radial Strength.............................................................................................14 
7.  Radial Outward Force....................................................................................................................14 
8.  Mechanical Properties....................................................................................................................15 
9.  Stress /Strain Analysis...................................................................................................................16 
10.  Fatigue Analysis............................................................................................................................19 
11.  Accelerated Durability Testing......................................................................................................20 
12.  Particulate Evaluation....................................................................................................................21 
13.  Magnetic Resonance Imaging (MRI) Safety and Compatibility....................................................23 
14.  Radiopacity....................................................................................................................................25 
15.  Crush Resistance (Peripheral Indications Only)............................................................................25 
16.  Kink Resistance (Peripheral Indications Only)..............................................................................26 
17.  Additional Tests for Stents Intended for In-Stent Restenosis........................................................26 
18.  Additional Tests for Stents Intended for Bifurcation Lesions.......................................................26 
C.  Delivery System Dimensional and Functional Attributes........................................................27 
1.  Dimensional Verification...............................................................................................................27 
2.  Delivery, Deployment, and Retraction..........................................................................................28 
3.  Balloon Rated Burst Pressure (Balloon Expandable Stents Only).................................................29 
4.  Balloon Fatigue (Repeat Balloon Inflations; Balloon Expandable Stents Only)...........................29 
5.  Balloon Compliance (Stent Diameter vs. Balloon Pressure; Balloon Expandable Stents Only)...30 
6.  Balloon Inflation and Deflation Time (Balloon Expandable Stents Only)....................................31  Contains Nonbinding Recommendations 
 
7.  Catheter Bond Strength..................................................................................................................31 
8.  Tip Pull Test...................................................................................................................................32 
9.  Flexibility and Kink Test...............................................................................................................32 
10.  Torque Strength.............................................................................................................................32 
11.  Coating Integrity............................................................................................................................33 
12.  Stent Securement for Unsheathed Stents.......................................................................................34 
D.  Shelf Life.......................................................................................................................................35 
E.  Biocompatibility...........................................................................................................................36 
V.  LABELING.....................................................................................................................39 
A.  Device Description.......................................................................................................................39 
B.  Indications for Use.......................................................................................................................40 
C.  Contraindications.........................................................................................................................40 
D.  Warnings.......................................................................................................................................40 
E.  Precautions...................................................................................................................................40 
F.  MR Environment.........................................................................................................................41 
G.  Overview of Clinical Studies.......................................................................................................41 
H.  Adverse Events.............................................................................................................................42 
I.  Clinical Studies.............................................................................................................................44 
J.  Principal Safety and Effectiveness Table...................................................................................45 
K.  Patient Selection and Treatment................................................................................................46 
L.  Directions for Use.........................................................................................................................46 
M.  Patient Materials..........................................................................................................................47 
APPENDIX A: TEST SUMMARY CHECKLIST..................................................................48 
APPENDIX B: APPLICABLE STANDARDS.........................................................................51 
  Contains Nonbinding Recommendations 
 
Guidance for Industry and FDA Staff
 
 
Non-Clinical Engineering Tests and 
Recommended Labeling for Intravascular 
Stents and Associated Delivery Systems 
 
This guidance represents the Food and Drug Administration's (FDA's) current thinking on 
this topic.  It does not create or confer any rights for or on any person and does not operate to 
bind FDA or the public.  You can use an alternative approach if the approach satisfies the 
requirements of the applicable statutes and regulations.  If you want to discuss an alternative 
approach, contact the FDA staff responsible for implementing this guidance.  If you cannot 
identify the appropriate FDA staff, call the appropriate number listed on the title page of this 
guidance. 
 
I. Introduction 
This guidance provides FDAs current thinking on non-clinical engineering tests that are 
submitted in investigational device exemption applications (IDEs) and premarket approval 
applications (PMAs) to support the safety and effectiveness of intravascular stents and their 
associated delivery systems.  This guidance also provides recommendations for labeling for 
these devices. 
 
FDA's guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the Agency's current thinking on a topic and 
should be viewed only as recommendations, unless specific regulatory or statutory 
requirements are cited.  The use of the word should in Agency guidances means that something 
is suggested or recommended, but not required. 
 
 
Definition of Terms Used in this Guidance 
Intravascular Stent 
Intravascular stents are also known as endovascular stents or vascular stents.  This 
document uses the term intravascular stent to refer to intravascular, endovascular, and 
vascular stents. 
 
An intravascular stent is a synthetic tubular structure intended for permanent implant in 
native or graft vasculature.  The stent is designed to provide mechanical radial support 
after deployment; this support is meant to enhance vessel patency over the life of the 
device.  Once the stent reaches the intended location, it is expanded by a balloon or self-
expanding mechanisms defined below.   
 
  1 Contains Nonbinding Recommendations 
 
Balloon Expandable Stent 
A balloon expandable stent is expanded by a balloon catheter.  The diameter of the stent 
increases as the balloon diameter increases.  The stent remains expanded after deflation 
of the balloon. 
 
Self-expanding Stent 
A self-expanding stents diameter increases from its pre-deployed size to its post-
deployed size in the absence of balloon inflation or other mechanical assistance. The self-
expanding quality can result from material properties or geometry or both. 
 
Stent Delivery System 
A stent delivery system delivers a stent to a target site and then deploys the stent. 
A stent delivery system for a balloon expandable stent consists of a balloon catheter.  
Self-expanding stent delivery systems may or may not include a balloon. 
 
 
II.  Scope 
This guidance document addresses self-expanding and balloon expandable extracranial 
intravascular stents and their associated delivery systems.  The scope includes extracranial 
intravascular stents placed in coronary or peripheral arteries and saphenous vein grafts but is not 
limited to stents used in these locations; other vascular indications outside of the intracranial 
vasculature are also included. 
 
Intravascular stents, including balloon expandable and self-expanding stents, are class III devices 
whose product codes are given in the table below. 
 
Table 1: Product Codes for Stents Addressed in this Guidance 
Product Code  Device 
MAF  Stent, Coronary 
NIM  Stent, Carotid 
NIN  Stent, Renal 
NIO  Stent, Iliac 
NIP  Stent, Superficial Femoral Artery 
 
These devices require a premarket approval (PMA) application before marketing.  See sections 
513(a) and 515 of the Federal Food, Drug, and Cosmetic Act (the Act) and 21 CFR Part 814.   
 
Clinical studies conducted in the United States in support of a PMA approval must be conducted 
under the Investigational Device Exemptions (IDE) regulation, 21 CFR Part 812.  FDA believes 
that the intravascular stents addressed by this guidance document are significant risk devices as 
defined in 21 CFR 812.3(m),1 and as such, are not exempt from the requirement to submit an 
                                                 
1 Refer to http://www.fda.gov/oc/ohrt/irbs/devices.html#risk. 
  2 Contains Nonbinding Recommendations 
 
investigational device exemption (IDE) application (21 CFR 812.2(b), 812.20(a)(1).  When an 
IDE application is required, a sponsor must not begin a clinical trial in humans in the United 
States until FDA has approved the application (21 CFR 812.20(a)(2), 812.42).  Sponsors of such 
studies must comply with the following: 
 
  IDE regulations (21 CFR 812)  
  Regulations governing institutional review boards (IRB) (21 CFR 56) 
  Informed consent (21 CFR 50). 2   
 
After FDA has approved a device, clinical studies conducted in accordance with the indications 
in the approved PMA, including clinical design validation studies conducted in accordance with 
the quality systems regulation, are exempt from the investigational device exemptions (IDE) 
requirements.  However, such studies must be performed in conformance with the regulations 
governing institutional review boards (21 CFR Part 56) and informed consent (21 CFR Part 50).  
 
Non-vascular stents meant for use outside the vasculature are not included in the scope of this 
document.  This document also does not include stents used in the intracranial vasculature. You 
should contact the Division of Reproductive, Abdominal, and Radiological Devices for 
information about biliary stents, the Division of Anesthesiology, General Hospital, and Infection 
Control Devices for information about non-vascular stents, or the Division of Ophthalmic, 
Neurological, and Ear, Nose, and Throat Devices for information about stents used in the 
intracranial vasculature. 
 
Some of the tests (and labeling recommendations) in this guidance are relevant to covered (NIV), 
drug-eluting (NIQ), and biodegradable stents, and stents used to treat aneurysms or dissections.  
However, FDA recommends additional testing to fully characterize these devices.    For drug-
eluting stents, please refer to the draft document Coronary Drug-Eluting Stents Nonclinical 
and Clinical Studies.3  For other coated stents, FDA recommends that you assess the need for 
additional testing to address coating characterization, coating integrity, and coating durability.  
The Interventional Cardiology Devices Branch and the Peripheral Vascular Devices Branch are 
available to discuss additional testing details for these stents and indications. 
 
This guidance document supplements other FDA publications on PMA, PDP, and IDE 
applications and should not be construed as a replacement for those documents.  For general 
information about these applications, see the CDRH Device Advice web site given below: 
  PMAs (21 CFR Part 814): 
http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/HowtoMarketYour
Device/PremarketSubmissions/PremarketApprovalPMA/default.htm   
                                                 
2
 You should review the statutory definition of applicable clinical trial to determine if your trial must be 
registered to comply with the law.  See PL 110-85, Section 801(a), (adding new 42 U.S.C. 282(j)(1)(A)).  
http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=110_cong_public_laws&docid=f:publ085.110.pdf   
Information can be submitted to ClinicalTrials.gov using the Protocol Registration System (PRS). For more 
information visit the PRS Information Page. 
3 http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM072193.pdf 
and http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM072196.pdf  
  3 Contains Nonbinding Recommendations 
 PDPs (21 CFR Part 814.19):
http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/HowtoMarketYour
Device/PremarketSubmissions/PremarketApprovalPMA/ucm048168.htm#pdp
 IDEs (21 CFR Part 812):
http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/HowtoMarketYour
Device/InvestigationalDeviceExemptionIDE/default.htm
This guidance also cites a number of voluntary standards, many of which are recognized by FDA.  
You may access a list of the FDA-recognized standards from the CDRH web site, 
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/search.cfm.  See also the guidance, 
Recognition and Use of Consensus Standards, https://www.fda.gov/downloads/
MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm077295.pdf
III. Content and Format of Test Data
A. Summary Reports
We recommend that you present test data in a summary that includes the elements described 
below. 
Table of Contents 
You should place a table of contents at the front of the document.  Each line listing in the table of 
contents should refer to major section titles and the page numbers where each section can be 
found. 
Test Summaries 
You should briefly describe all tests performed. 
Test Data Summaries  
You should include test data summaries for all tests.  The summaries should contain: 
 minimum measured value (min)
 maximum measured value (max)
 mean
 standard deviation of the test data (std. dev.).
Summary of Conclusions 
You should summarize your conclusions regarding whether the results support the safety and 
effectiveness of your device for each test. 
4 Contains Nonbinding Recommendations 
B. Test Reports
You should include full test reports for all tests performed.  Your test reports should include the 
sections described below. 
Test Specimen Information 
Your test specimen description should include: 
 number of test specimens
 size (diameter, length, or other relevant dimensions) of all test specimens
 rationale for the number of test specimens and sizes tested
 whether the specimens represent the finished product
 sterilization parameters and number of sterilization cycles applied to the test specimens.
Test Protocol 
You should submit your test method or protocol.  It should contain enough detail that an 
individual familiar with intravascular stent testing will be able to interpret the test results. 
Protocol Deviations 
You should describe any protocol deviations and their effect on the ability of the test data to 
support the safety and effectiveness of the device. 
Test Parameters and Acceptance Criteria 
You should report the test parameters and acceptance criteria that you use, including: 
 an explanation of and rationale for critical test parameters
 specifications or acceptance and rejection criteria
 a rationale for the specification or acceptance and rejection criteria based on the
clinical requirements of the device.
Raw Data 
We recommend that you include all raw data in appendices or on a CD-ROM, or make the 
raw data available for our review upon request. 
Test Results 
You should summarize your test results and include statistical analysis when it is appropriate. 
Data Analysis 
You should analyze the data, including any outlying points and anomalous results, and 
explain whether the data meet the given acceptance criteria. 
Conclusions 
We recommend that you describe the conclusions drawn from the test results, and the clinical 
significance of the conclusions. 
5 Contains Nonbinding Recommendations 
C. Test Protocols
You should establish protocols for all experiments or computational analyses, including 
acceptance criteria when applicable, before you perform the tests.  Established test protocols help 
to ensure consistent repetition of tests and allow comparison of data between test runs. 
We are willing to informally review and provide comments on test protocols prior to conduct of 
a test, if there are aspects of a particular test that you feel might benefit from FDA input.  While 
FDA does not approve test protocols, our input before testing may improve your ability to 
demonstrate the performance characteristics of your device. 
Your test protocols should assess device performance when exposed to the most extreme clinical 
conditions that your device is likely to experience.  Both device configuration and physiologic 
conditions affect the performance of devices in the human body.  We recommend that you 
evaluate extreme device dimensions, tolerances, sizes, and any other important device 
parameters in your testing program.  We also recommend that you examine the outer limits of 
physiologic variables such as blood pressure, vascular compliance, and anatomic types.  You 
should clearly state all test conditions in the test protocol and support them with references to 
applicable literature, standards, or both. 
Occasionally, the worst performing combination of device configuration and physiologic 
conditions occurs in the mid-range of the relevant variables.  You should check for this situation 
when developing your protocols to ensure that you test the worst performing combination. 
Several of the tests listed in this guidance do not apply to all intravascular stents and delivery 
systems.  The designs or clinical indications to which these tests do apply are noted in their 
descriptions.  We believe that each test helps to support the safety and effectiveness of 
intravascular stents for their stated indication.  Each tests clinical or engineering significance is 
described in Section V.   
If you believe a test recommended in this guidance does not apply to your device, you should 
include a heading for the test in your test summary, followed by an explanation of why the test is 
not applicable.  We will then be aware that you did not inadvertently omit it from your 
application.   
Your explanation should include a rationale for why you do not think the test should be 
performed in order to support the safety and effectiveness of your device.  Your rationale should 
clearly demonstrate, by reference to a Failure Modes and Effects Analysis (FMEA) or other risk 
analysis method, that the particular test or data set is not necessary or appropriate to support the 
safety and effectiveness of your device.  Alternatively, you may identify measures you have 
taken to mitigate the risks associated with the device in the failure mode that would usually be 
evaluated using the test that you have not performed. 
Intravascular stents have been in clinical use for over a decade and some designs are in their 
fourth or fifth generation.  Some attributes may not be modified when changes are made in the 
design of a next-generation device.  For a particular attribute, rather than providing original data 
for a next-generation design, it may be appropriate to reference previously tested stents in the 
6 Contains Nonbinding Recommendations 
 
same device family.  However, a reference to previous generic device experience, for example, 
alloy X has been used in stents, generally is not adequate.  If you choose to reference testing 
previously performed on already marketed stents, you should explain why the previous testing is 
relevant.  If a particular attribute of the next-generation device is re-evaluated, a comparison of 
the results to those of the previous generation may be helpful.   
 
Sample Selection 
You should use a statistically significant sample size whenever possible.  When using a 
statistically significant number of samples is not possible, you should provide a scientific 
rationale to support the number of samples tested in your test summary and test protocols, and 
provide reasonable assurance that the test results support the safety and effectiveness of the 
device. 
 
All test samples should represent the finished product.  Your devices should be sterilized by the 
final production process, including repeat sterilization cycles.  You should note any tests that use 
samples that are not finished, sterilized product in the test summary and test protocols, and 
explain why doing so does not affect the applicability of the test results to the evaluation of 
safety and effectiveness of the device. 
 
You should test the full range of sizes that you intend to commercially distribute.  The 
recommended default paradigm is a 2 x 2 factorial of the largest and smallest diameters and 
lengths, also known as the four corners paradigm for each different stent design.  We 
recommend a different set of sizes for some of the tests in Section V.  Table 2 illustrates the four 
corners concept for a typical coronary stent.  If you do not test a device using the four corners 
paradigm or the recommended sizes for a particular test, you should provide a scientific rationale 
to support the sizes that you do test in the test summary and test protocols.  For some tests, we 
may recommend that you perform an analysis to identify the size or sizes that represent the worst 
case. 
 
Table 2: Four Corners Test Paradigm Example 
 
Stent  Stent Length 
Diameter  (mm) 
(mm)  8  12 18 24
2.5  X     X 
3.0         
3.5         
4.0  X     X 
             X = Recommended sizes for testing 
 
 
 
 
 
 
 
  7 Contains Nonbinding Recommendations 
IV. Non-Clinical Engineering Tests
A. Material Characterization
1. Material Composition
Significance
Material composition testing documents a baseline for evaluation of the effects of
future changes in materials.
Recommendation
We recommend that you specify the device characteristics described below.  If your
stent material is identical to your previously marketed stents, we recommend that you
identify the stent(s) and material(s) to which it is identical.
Stent and Delivery System Materials 
We recommend that you list materials by trade or common name, for example, 
316L stainless steel. 
Generic Chemical Formulation 
We recommend that you list formulations of all materials by generic name, for 
example, 18 Cr-14 Ni-2.5 Mo stainless steel.  We recommend that you reference 
any applicable standard designations such as ASTM F138.4 
Chemical Composition and Formulation 
We recommend that you provide detailed specifications for the chemical 
composition or formulation of materials (or both) for any new materials, alloys, or 
formulations with no history of use in intravascular stents or PTCA catheters. 
Surface finish is known to affect other material properties for nitinol (e.g. 
corrosion, nickel ion release).  Therefore, for stents containing nitinol, we 
recommend that you characterize the material surface of your finished product in 
terms of passivation layer microstructure vs. depth.  Special attention should be 
paid to surfaces which might include heat-affected zones (e.g., from laser cutting), 
or to geometric areas which may be affected differently by finishing (e.g., internal 
angles). 
Material Certification 
We recommend that you provide documentation to certify that incoming raw 
material conforms to specifications.  We recommend that you submit supplier 
certification, incoming quality control test results, or equivalent documentation.   
4 ASTM F138 Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and 
Wire for Surgical Implants 
8 Contains Nonbinding Recommendations 
2. Shape Memory and Superelasticity of Intravascular Stents
Significance
The transition temperature of nitinol or other shape memory and superelastic
materials determines specific shape memory and superelastic properties.
Recommendation
We recommend that you document the following properties for any shape memory or
superelastic materials present in your stent.
Austenite Finish Transition Temperature (Af) 
We recommend using the methods described in ASTM F2004,5 ASTM F2082,6 
or equivalent methods. 
Mode of Action 
We recommend that you describe the mode of action (e.g., thermal shape memory 
or superelasticity) by which the stent transitions to the specified size and shape.  
3. Stent Corrosion Resistance
Significance
Stent corrosion can cause or contribute to premature stent failure.  In addition,
corrosion byproducts may be toxic or cause other adverse biological and tissue
responses.
Recommendation
We recommend that you address the corrosion properties of your device described
below.  If some of these characteristics do not apply to your device, we recommend
that you explain this in your application.
Fretting Corrosion 
We recommend that you address the potential for fretting corrosion between two 
stents since there is a reasonable expectation of stent overlap during clinical use 
for most indications.   We recommend that the examination of samples for fretting 
corrosion be incorporated as part of fatigue/durability testing (see Section B.11. 
Accelerated Durability Testing).  You should ensure that overlapping stents are 
in contact with one another and that the setup does not preclude micromotion 
between strut elements.   For coronary stents, because tortuosity of a target 
deployment site could result in increased micromotion between components or 
multiple stents, the mock deployment site should be bent to a worst-case clinically 
relevant radius of curvature, which should be smaller than most anatomical 
5 ASTM F2004 Standard Test Method for Determination of Transformation Temperature of Nickel-Titanium Alloys 
by Thermal Analysis 
6 ASTM F2082 Standard Test Method for Determination of Transformation Temperature of Nickel-Titanium Shape 
Memory Alloys by Bend and Free Recovery 
9 Contains Nonbinding Recommendations 
situations encountered in clinical use.  For example, for most coronary 
indications, FDA recommends a 15mm radius of curvature as this represents 
worst case for 90% of the population based on published angiographic 
measurements.7  For other indications such as use in coronary bifurcations, please 
provide a similarly robust clinical rationale for the radius of curvature selected.  
We recommend conducting a visual (e.g., SEM) inspection of samples after 
fatigue/durability testing for evidence of corrosion.   
Results from testing through one year time equivalent should be provided in 
support of an IDE application.  Results from testing through ten years time 
equivalent should be provided when they are available, but not later than at the 
time of PMA submission.  A scientific rationale for the number of samples 
evaluated for fretting corrosion should be provided. 
Pitting and Crevice Corrosion Potential 
We recommend that you characterize the corrosion potential of your stent with 
any potential surface damage that may result from fatigue.  We recommend 
testing the same samples used in the fretting corrosion evaluation described above 
according to the method in ASTM F2129.8  Specifically, one stent from each 
overlapping pair subjected to fatigue cycling should be evaluated for pitting and 
crevice corrosion potential while the other stent from each pair is evaluated for 
fretting corrosion as described above.  Test reports for pitting and crevice 
corrosion potential testing should include the recorded potentials as well as the 
polarization curves.   
Results from testing through one year time equivalent should be provided in 
support of an IDE application.  Results from testing through ten years time 
equivalent should be provided when they are available, but not later than at the 
time of PMA submission.   
If results do not indicate an acceptable pitting and crevice corrosion potential, you 
should consider characterizing the corrosion potential of the finished, as 
manufactured stent to determine if the corrosion potential of your stent is affected 
by fatigue.  
You may use literature citations or previous experience with stents to address this 
issue; however, the materials, design, and fabrication processes specific to your 
stent may reduce or eliminate the applicability of generic literature.  For example, 
the pitting corrosion resistance of nitinol is sensitive to processing variables such 
as heat treatment and electropolishing; therefore, for a nitinol stent, you should 
characterize the corrosion potential of the finished stent.  
7 Liao R, Green NE, Chen SY, Messenger JC, Hansgen AR, Groves BM, Carroll JD.  Three  dimensional analysis 
of in vivo coronary stent  coronary artery interactions.  International Journal of Cardiovascular Imaging. 2004 
Aug;20(4):305-13. 
8 ASTM F2129 Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements to 
Determine the Corrosion Susceptibility of Small Implant Devices 
10 Contains Nonbinding Recommendations 
Galvanic Corrosion 
If your stent contains more than one type of metal, such as a base stent material 
with added marker bands, we recommend that you demonstrate the designs 
resistance to galvanic corrosion.  If you expect that your stents will be overlapped 
during clinical procedures, and the contacting or overlapping stents may be made 
of different materials, we recommend that you address the potential for galvanic 
corrosion between stents.  In this case, we recommend that you use the marketed 
stent with the highest galvanic coupling with your stent material in your 
evaluation.  We recommend the methods described in ASTM G719 or their 
equivalents.  These methods may be modified to provide for testing of finished 
stents, for example, by incorporating the experimental setup described in 
Appendix X3 of ASTM F2129. 
Testing should be conducted even if an alloy conforms to a specific standard 
because manufacturing processes can affect the galvanic corrosion potential of the 
finished product.   
B. Stent Dimensional and Functional Attributes
1. Dimensional Verification
Significance
Accurate stent dimensions help the physician to achieve proper stent sizing and
accurate placement in the body.  They also affect the functional behavior of the stent.
Recommendation
FDA recommends that you provide the information described below that applies to
your stent.  We recommend the methods used in ASTM F208110 or their equivalents.
At a minimum, you should take measurements at each end and in the middle of the
stent and at two circumferential points 90  apart (for a total of six measurements).
You should take additional measurements as appropriate based on device design.
Un-expanded Stents 
We recommend that you provide dimensional specifications and tolerances for 
un-expanded stents.   
Balloon Expandable Stents 
We recommend that you measure and report the expanded diameter of balloon 
expandable stents.  You may do this as part of the process of creating a 
compliance chart.  See Section C.  Delivery System Dimensional and 
Functional Attributes, 5.  Balloon Compliance. 
9 ASTM G71 Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes. 
10 ASTM F2081 Standard Guide for Characterization and Presentation of the Dimensional Attributes of Vascular 
Stents 
11 Contains Nonbinding Recommendations 
Self-Expanding Stents 
We recommend that you verify the unconstrained expanded diameter of self-
expanding stents with measurement data. 
2. Percent Surface Area
Significance
The area over which a stent contacts a vessel may affect the biologic response of the
vessel.  The amount of open, non-contact area may influence tissue prolapse or
ingrowth.
Recommendation
We recommend that you report the percent surface area of the stent for both the
smallest and largest nominal expanded diameters for each stent design.  We
recommend that you evaluate different lengths only if you expect that the percent
surface area varies significantly with stent length.  We recommend that you measure
or calculate the contact area of the stent structure, and express the final value as a
percentage of the reference area, as shown below:
Percent Surface Area = 100 x (Area in Contact with Vessel  Full Cylindrical Surface
Area)  
(The reference area is defined as the full cylindrical surface area at the expanded stent 
diameter.)  We recommend that you apply the methods described in ASTM F2081 or 
their equivalents. 
3. Foreshortening
Significance
Foreshortening, i.e., dimensional changes that may occur when deploying a stent,
influences final stent length.  Knowledge of the foreshortening characteristics aids in
proper stent length selection and proper placement in the body.
Recommendation
FDA recommends that you report the decrease in length of the stent between the
catheter-loaded condition and the deployed diameters up to the maximum labeled
diameter.
We recommend that the reported value reflect the maximum nominal diameter.  We
recommend that you report the results in terms of a percentage of the loaded length as
shown below:
Percent Foreshortening = 100 x (Change in Length  Loaded Length). 
We recommend that you apply the methods described in ASTM F2081 or their 
equivalents. 
12 Contains Nonbinding Recommendations 
 
See Section VIII.  Labeling for recommendations on data presentation of the percent 
foreshortening of self-expanding stents. 
 
4.  Recoil for Balloon Expandable Stents 
Significance 
The recoil behavior of balloon expandable stents influences proper device selection, 
sizing, acute post-implant results, and long-term clinical outcomes.  Recoil is a 
function of stent design and material selection; therefore, knowledge of stent recoil 
helps to characterize the behavior of a particular stent design. 
 
Recommendation 
We recommend that you report the measured change in diameter of your stent 
between post-balloon expansion and after balloon deflation. 
 
We recommend that you measure and report values for each labeled stent diameter.  
If you expect that the percent recoil varies significantly with length, we recommend 
that you evaluate recoil for different stent lengths at various points along the length of 
the stent, including the ends.  The number of locations along the length of the stent at 
which recoil is measured should be determined by initial assessment of the stent 
geometry. 
 
We recommend that you present the results as a percentage of the expanded diameter. 
 
We recommend the methods described in ASTM F207911 or their equivalents. 
 
5.  Stent Integrity 
Significance 
Stent defects, whether a result of manufacturing flaws or subsequent damage, can 
contribute to clinical complications.  Laser cutting or other manufacturing processes 
may induce flaws that are not completely removed by polishing.  Plastic deformation 
during loading or balloon expansion may cause cracks or other damage.  Self-
expanding stents that are stored loaded in a delivery system may exhibit permanent 
set or changes in expansion characteristics as a result of time or sterilization or both. 
 
Recommendation 
We recommend that you examine your deployed stent and report any evidence of 
stent defects such as, but not limited to: 
  cracks 
  scratches 
  permanent set 
  coating delamination. 
 
                                                 
11 ASTM F2079 Standard Test Method for Measuring Intrinsic Elastic Recoil of Balloon expandable Stents 
  13 Contains Nonbinding Recommendations 
 
We recommend that you use optical or electron microscopy, or both to look for 
defects.  We recommend that you support the level of magnification that you use on 
the basis of the size of the defect that your inspection attempts to detect.   
 
When you are looking for post-deployment damage, we recommend that you examine 
or inspect:
 
  balloon expandable stents, after expansion to the largest diameter listed in 
your labeling
 
  self-expanding stents, after expansion to the unconstrained diameter. 
 
6.  Radial Stiffness and Radial Strength 
Significance 
Radial stiffness and stent recoil determine the diameter of balloon expandable stents 
deployed in compliant vessels.  Radial stiffness and radial strength characterize the 
ability of the stent to resist collapse under short-term or long-term external loads. 
 
Recommendation 
We recommend that you report a value for the following: 
  radial stiffness, i.e., the change in stent diameter as a function of uniformly 
applied external radial pressure; and 
  radial strength, i.e., the pressure at which your stent experiences irrecoverable 
deformation. 
 
FDA recommends that you measure and report values for each labeled stent diameter.  
If you expect that the radial stiffness varies significantly with length, we recommend 
that you also evaluate different stent lengths. 
 
We recommend that you support the diameter or pressure range used in your tests for 
radial stiffness.  The diameter and pressure range will probably vary depending on 
your stents intended target site. 
 
7.  Radial Outward Force 
Significance  
It is important to characterize the radial outward force of self-expanding stents.  
Excessive radial force could injure the surrounding tissue, while a radial force that is 
too low can result in incomplete apposition of the stent to the vessel wall.  
 
Recommendation  
We recommend that you measure the radial force exerted by self-expanding stents 
against the vessel wall after deployment.  If a particular stent size or model is 
indicated for use in a range of vessel sizes, your assessment should cover the range of 
possible vessel sizes, or should include a rationale for not assessing the entire size 
range to be marketed.  We recommend that you evaluate different stent lengths if you 
expect that the radial force varies as a function of the total stent length.  In addition, if 
  14 Contains Nonbinding Recommendations 
 
you expect that the radial force of your stent is not axially uniform (for example, if 
your stent has a tapered length), we recommend that you measure the radial force at 
multiple locations along the length of the stent.  The specifications for radial outward 
force should include both minimum and maximum values. 
 
8.  Mechanical Properties 
Significance 
Raw material properties determine incoming material quality and uniformity, and 
predict subsequent thermomechanical effects.  Thermomechanical properties of the 
implanted stent affect clinical performance, as well as stress and fatigue behavior. 
 
Recommendation 
We recommend that you specify the mechanical properties listed below for the stent 
raw material(s). 
 
Mechanical Properties of the Raw Material(s) 
  ultimate tensile strength (UTS) 
  yield strength (YS) 
  elongation 
  plateau stresses, for nitinol 
  elastic strain limits, for nitinol. 
 
Post-Processing Mechanical Properties 
FDA also recommends that you report the stress-strain response of the stent after 
deployment.  We recommend that you present the stress-strain behavior in a plot 
or graph that shows both loading and unloading.  We recommend that you report 
the following post-processing mechanical properties of your stent: 
  UTS 
  YS 
  elongation 
  elastic modulus 
  Poisson ratio 
  endurance limit 
  plateau stresses, for nitinol 
  elastic strain limits, for nitinol. 
 
In addition, reporting other mechanical properties at previous stages of manufacture, 
may allow characterization of your material for use in your stress/strain analysis.  See 
Section 9.  Stress/strain Analysis.  We recommend that you determine the stress-
strain response, endurance limit, and post-processing mechanical properties through 
physical experiments or computational models that simulate stent material properties, 
manufacturing, and deployment processes.  If you cite any quoted literature or 
  15 Contains Nonbinding Recommendations 
 
handbook values, we recommend that you explain how they are relevant to your 
device.  Since the material properties of nitinol are widely variable depending on 
processing, we recommend for nitinol devices that you perform physical experiments 
on actual post-processing samples to determine the mechanical properties of your 
stent.  We also recommend that you use and reference standard test methods 
whenever possible, and describe any nonstandard test methods in detail. 
 
9.  Stress /Strain Analysis 
Significance 
Failure of a loaded stent may result in loss of radial support of the stented vessel or in 
perforation of the vessel by the stent struts.  Stress/strain analysis, combined with 
fatigue analysis and accelerated durability testing, provides an indication of device 
durability. 
 
Recommendation 
FDA recommends that you include the following elements in your stress/strain 
analysis and test report for each stent design. 
 
Computational Model and Inputs 
We recommend that you clearly identify and explain the sources and values of all 
inputs and assumptions used to create the stress/strain analysis model.  You 
should identify any software used for analysis.  We recommend that finite 
element analysis reports include the element types used to model the stent, 
loading surfaces, and boundary conditions.  We also recommend that you indicate 
if mesh refinement analysis was performed and clearly describe how you model 
the surrounding vessel/tissue and the type of contact elements used.  Specifically, 
we recommend that you consider the following: 
 
  Model Geometry 
We recommend that you clearly describe the stent and vessel geometry 
used.  If symmetry is used, we recommend that you explain why this is 
appropriate for your model. 
 
If you do not model all of your stent sizes, we recommend that you 
explain why the modeled stent size is the worst case with respect to 
critical stresses.  We recommend that you address the effect of 
dimensional variation within allowable tolerances on the results of the 
stress/strain analysis (i.e., maximum critical stress).   
 
We recommend that you provide a justification for the physiological 
relevance of your vessel model parameters (e.g., vessel compliance). 
 
 
 
 
  16 Contains Nonbinding Recommendations 
 
  Type of Element & Mesh Refinement Analysis 
We recommend that you specify the number and type of elements used in 
your mesh, including any mesh refinement in transition regions or regions 
of complex geometry.    
 
We recommend that you perform a mesh refinement analysis to ensure 
that the solution is independent of element size.  If you do not believe 
mesh refinement analysis is necessary for your model, we recommend that 
you provide a justification for not conducting such an analysis. 
 
  Contact Elements 
We recommend that you specify the type of contact defined between any 2 
contacting bodies modeled in your analysis; e.g., the vessel and outer 
surface of your stent. 
 
  Material Properties (Constitutive Model) 
We recommend that you clearly describe the material stress/strain 
behavior of your stent in graphical and equation form.  This discussion 
should include, but is not limited to the following considerations: 
o  Linear vs. non-linear 
o  Isotropic vs. anisotropic 
o  Temperature-dependent behavior 
o  Raw vs. processed material. 
 
  Finite Element Analysis (FEA) Validation 
We recommend that you validate your FEA (material properties, 
geometry, and boundary conditions) with experimental bench testing. For 
example, you could perform radial loading of your device and compare the 
force-displacement results with FEA of a simulated radial loading 
experiment. 
 
Stress/Strain History 
FDA recommends that you include the entire stress history of the device in each 
loading step in order to incorporate the effects of residual stresses.  The entire 
stress history may include, but is not limited to: 
  manufacturing (fabrication, annealing, electropolishing, heat-setting, etc.) 
  loading onto the delivery system and/or crimping 
  expansion/deployment (including over- or underexpansion into an elastic 
vessel, if applicable) 
  stent recoil 
  physiologic loading conditions. 
 
If you believe that you do not need to model the entire stress history, we 
recommend that you use material properties that are consistent with the starting 
point of your analysis.  We recommend that the material properties accurately 
  17 Contains Nonbinding Recommendations 
 
reflect the processing history of the stent as described in Section 8.  Mechanical 
Properties.  We also recommend that you explain why the omitted loading steps 
either do not affect the stent fatigue life or are accounted for in your model. 
 
Physiologic Loading Conditions 
The modeled physiologic loading mode will depend on the implantation site and 
may include, but is not limited to the following: 
  radial dilation 
  torsion 
  bending 
  axial tension 
  axial compression 
  crushing, including focal, non-focal, or uniform radial compression. 
 
We recommend that you address the list above as well as any other relevant 
loading conditions when you develop the model for your stent. 
 
If you expect that your stents will be overlapped during clinical procedures, then 
we recommend that you address the possibility of the additional stress 
concentrations caused by overlapping stents.   
 
We believe that most coronary stents indicated for use in non-bifurcated vessels 
should be modeled using radial dilation in a static bend to represent potential 
tortuosity of the target lesion.  We recommend that you perform your stress/strain 
analysis such that the stent is in a mock deployment site bent to a clinically 
relevant radius of curvature as described in Section IV. Non-Clinical 
Engineering Tests A. Material Characterization 3. Stent Corrosion 
Resistance  Fretting Corrosion.  You may also wish to consider dynamic 
bending to better evaluate the performance of your stent in clinical use conditions.   
 
For non-coronary stents, long stents, and coronary stents used in other vessel 
configurations such as bifurcation lesions, we recommend that you determine the 
relevant loading conditions. 
 
Results: Stress or Strain Critical Locations and Magnitude 
We recommend that you identify the critical locations of stress or strain on the 
stent using finite element analysis and address the effect of dimensional variation 
within allowable tolerances on the results.  We recommend that you report the 
location and magnitude of all maximum tensile and compressive stresses or 
strains as well as the stress-strain distribution using graphics.  The stress or strain 
measure used should be clearly defined (e.g., principal stresses, Von Mises 
stresses, etc.).  We recommend that you explain why the measure used is 
reasonable considering your constitutive model.  Additionally, we recommend 
that you explain what safety issues may arise if the stent fails in the region of 
maximum stress or strain. 
  18 Contains Nonbinding Recommendations 
 
 
If you choose to perform a strain-based analysis instead of a stress-based 
analysis, we recommend that you explain why the strain-based analysis is 
more appropriate for your device. 
 
10. Fatigue Analysis 
Significance 
Failure of a stent due to fatigue may result in loss of radial support of the stented 
vessel, thrombus formation or focal restenosis, or in perforation of the vessel by the 
stent struts.  Fatigue analysis, combined with stress/strain analysis and accelerated 
durability testing, provides an indication of device durability. 
 
Recommendation 
FDA recommends that you determine the fatigue resistance of the stent to physiologic 
loading using a Goodman analysis or another fatigue life analysis method.  We 
recommend that your test report include the following elements. 
 
Modeled Stent Sizes 
If you do not analyze all stent sizes, we recommend that you explain why the 
modeled stent size is the worst case for fatigue life. 
 
Inputs and Assumptions 
FDA recommends that you use the mean and alternating stresses/strains obtained 
from the stress/strain analysis as input for the fatigue life determination.  We 
recommend that you clearly identify and support all inputs and assumptions used 
in your analysis.  If you use literature values for any material properties, we 
recommend that you identify the source of the data and support that your values 
correspond to the as-implanted condition of the material. 
 
If you expect that your stents will be overlapped during clinical procedures, we 
recommend that you address the possibility of the additional stress concentrations 
caused by overlapping stents.   
 
We believe that most coronary stents indicated for use in non-bifurcated vessels 
should be modeled using radial dilation in a static bend to represent potential 
tortuosity of the target lesion.  We recommend that you perform your stress/strain 
analysis such that the stent is in a mock deployment site bent to a clinically 
relevant radius of curvature as described in Section IV. Non-Clinical 
Engineering Tests A. Material Characterization 3. Stent Corrosion 
Resistance  Fretting Corrosion. 
 
Since the material properties of nitinol are widely variable depending on 
processing, we recommend for nitinol devices that you perform physical 
experiments on actual post-processed samples to determine the mechanical 
properties of your stent, and use these values in your analysis. 
  19 Contains Nonbinding Recommendations 
Results 
We recommend that you provide a Goodman diagram or other graphic that 
compares the stresses at critical locations in the stent to the mechanical properties 
of the stent material.  We recommend that you report fatigue safety factors in a 
table and explain how the safety factors were calculated. 
If you choose to perform a strain-based analysis instead of a stress-based 
analysis, we recommend that you explain why the strain-based analysis is 
more appropriate for your device. 
11.Accelerated Durability Testing
Significance
Accelerated durability testing validates fatigue analysis.  It evaluates failure modes
such as fretting, abrasion, wear, and fracture.  Durability testing can help in the
identification of device conditions, such as manufacturing anomalies, that were not
modeled using analytical or computational methods.
Recommendation
FDA recommends that accelerated durability testing of your stent address the
following issues.
Sample Size 
We recommend that you determine sample size based on your fatigue analysis, 
including boundary conditions, loading conditions, safety factors, and any other 
relevant factors. 
We recommend that you consider a stent as one test specimen when you report 
reliability calculations and results.  We recommend that you consider the stent as 
one test specimen regardless of the symmetries present in apices, repeat units, or 
struts of the stent. 
Sizes Tested 
We recommend that you select and support the stent size or sizes tested based on 
the stress and fatigue analyses or other factors.  We recommend that the sizes 
tested represent the worst case fatigue life of your device. 
Test Duration 
We recommend that you test the durability of your stent to the equivalent of ten 
years of real-time use under pulsatile flow and physiologic loading that simulates 
blood pressure conditions in the human body.  We believe that ten years of 
durability data provides sufficient proof of safety of the device for most patients.  
If you perform a rigorous and conservative fatigue analysis that indicates an 
acceptable analytical safety factor, you may propose to complete long-term 
durability testing concurrent with clinical trials and to submit the final results 
20 Contains Nonbinding Recommendations 
when they are available, but not later than at the time of PMA submission.  In this 
case, results from testing through a minimum of one year time equivalent should 
be provided in support of an IDE application.  
Loading and Boundary Conditions 
FDA recommends that you perform long-term durability testing that models the 
physiological loads and boundary conditions that your stent is likely to experience 
under its intended use. 
We recommend that you address any other types of cyclic loading, such as 
bending, that you anticipate your stent will experience when used as intended, and 
incorporate these types of loading into your testing where possible.  We 
recommend that you explain the clinical relevance of the loading conditions used 
for the accelerated durability testing.  If the conditions you choose differ from the 
loading conditions that you modeled in the stress and fatigue analyses, we 
recommend that you report and explain the differences. 
Stent systems should be tracked through a clinically relevant test fixture prior to 
deployment.   
Overlapping Stents 
If you expect that your stents will be overlapped during clinical procedures, we 
recommend that you address the possibility of the additional risk of stent failure 
caused by wear or other factors. Therefore, you should test overlapping stents as 
part of the durability experiment. 
Deployment Site 
The testing should be relevant for your intended clinical use and condition.  For 
example, we believe that most coronary stents indicated for use in non-bifurcation 
vessels should be deployed in a mock vessel bent to a clinically relevant radius of 
curvature as described in Section IV. Non-Clinical Engineering Tests A. 
Material Characterization 3. Stent Corrosion Resistance  Fretting 
Corrosion.   
Results 
We recommend that you relate the outcome of your test to the stress and fatigue 
analysis results. 
12.Particulate Evaluation
Significance
Particulate matter can be generated by the manufacturing process or from the
breakdown of any coating (e.g., hydrophilic coating) or from the stent platform, stent
delivery system, or product packaging.  If particles are introduced in the bloodstream
during stent delivery or deployment, they may present an embolic risk to the patient.
21 Contains Nonbinding Recommendations 
 
Measurement of the total quantity and size of particulates a device system may 
generate is an indication of embolic risk.  Therefore, evaluation of particulate 
generation, size, and its potential impact on the end organ served by the stented 
vessels is critical. 
 
Recommendation 
We recommend that you measure the total number of particulates and size of the 
particulates generated during the simulated delivery and deployment of all coronary 
stents and any other stents that are determined to be high particulate risk based on a 
risk analysis that takes into account the clinical setting and susceptibility of the end 
organ to damage from emboli. 
 
Test Samples 
You should conduct all testing on the finished product subject to all 
manufacturing processes including sterilization.  You should evaluate a robust 
number of stents from multiple stent lots (minimum of 3 batches) and specify the 
number of samples (we recommend that a sample equals one stent, not a strut or 
portion of a stent) used, the stent size(s), and the number of stent lots for each test.  
We recommend that you implement a sampling plan to examine multiple lots of 
product to assess both inter- and intra- lot variability.  You should perform testing 
on sizes that represent four corners of the stent design (see Table 2 above) as well 
as an intermediate size.  You should provide a scientific or statistical justification 
for the selection of samples.   
 
It may be possible to combine the Particulate Evaluation with Delivery, 
Deployment and Retraction testing (see Section IV. Non-Clinical Engineering 
Tests C. Delivery System Dimensional and Functional Attributes 2. Delivery 
Deployment and Retraction) and/or with Coating Integrity testing (see Section 
IV. Non-Clinical Engineering Tests C. Delivery System Dimensional and 
Functional Attributes 11. Coating Integrity) but you should take care to ensure 
that only minimal additional handling of the test samples is required for the 
coating integrity evaluation such that particulates are neither lost nor generated. 
 
Test Methods 
We recommend using an in vitro modelintended to mimic in vivo physiologic and 
 
anatomic worst-case conditions (e.g., tortuous path, aqueous environment) to 
evaluate particulates.  For coronary indications, FDA recommends the tortuous 
path described by Figure X2.4 of ASTM F239412.  If you expect your stents may 
be deployed in an overlapped configuration during clinical procedures, we 
recommend that you measure particulates generated during deployment of two 
overlapping stents in a mock vessel.  For coronary stents, the mock vessel should 
be bent to a clinically relevant radius of curvature as described in Section IV. 
Non-Clinical Engineering Tests A. Material Characterization 3. Stent 
                                                 
12 ASTM F2394 Standard Guide for Measuring Securement of Balloon Expandable Vascular Stent Mounted on 
Delivery System 
  22 Contains Nonbinding Recommendations 
 
Corrosion Resistance  Fretting Corrosion.  The stent should be in direct 
contact with the simulated vessel without the use of other coatings, lubricants, 
sheaths, or protective wraps between the stent and the simulated vessel.  To 
ensure measurement of the total number of particles that could be potentially 
introduced into the bloodstream, the stent delivery system should be inserted into 
the text fixture to the extent which it would be inserted in clinical use and 
expanded to rated burst pressure (for balloon-expandable stents) or the maximum 
labeled diameter (for self-expanding stents).  Additionally, any accessory devices 
required for the placement of the product should be used in this evaluation.  The 
total number of particulates including those from the stent, delivery system, and 
accessory devices should be reported in each of three size ranges: 10m, 
25m, and at the largest size for which validation yields 75% recovery.  At a 
minimum, the largest size should be 50m.  Appropriate precautions should be 
implemented to ensure that the particles are suspended during sampling for 
particle counting and sizing to minimize artifacts from the test system.   
 
Validation 
You should describe and validate particle counting and sizing methods.  We 
recommend that a known amount of various particle sizes be introduced into the 
test setup and the amount of particles recovered quantified.  The number of 
particles recovered should closely approximate the number artificially introduced 
into the system.  For a system to be considered validated, 90% recovery should 
be demonstrated for the 10m and 25m size ranges.   
 
13. Magnetic Resonance Imaging (MRI) Safety and Compatibility 
Significance 
MRI of patients with stents poses the following potential hazards: 
  movement of the implant, resulting in tissue damage or misplacement 
  heating of the implant and subsequent tissue damage 
  image artifacts that may render the MR images uninterpretable or misleading. 
 
Recommendation 
FDA recommends that you address the issues affecting safety and compatibility of 
your stent in the MRI environment as described in the Guidance for Industry and 
FDA Staff:  Establishing Safety and Compatibility of Passive Implants in the 
MR (Magnetic Resonance) Environment.13 
 
Test Environment 
We recommend that you report details of the test environment, such as, but not 
limited to:   
  magnetic field strength in Tesla (T) 
  maximum spatial gradient 
                                                 
13 http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm107705.htm 
  23 Contains Nonbinding Recommendations 
 
  maximum time rate of change of magnetic field (dB/dt) 
  local specific absorption rate (SAR) at the position of the stent in the 
phantom 
  calorimetric assessed phantom averaged whole body specific absorption 
rate. 
  heating data versus time 
  close-up photos of temperature probe placement 
  overview photos of the placement of the stent in the phantom 
  details about the phantom gel 
  details about the pulse sequence 
  temperature increase at the location of the stent but without placing the 
stent in the gel 
  close-up photo of the stent including the stent dimensions 
  B1  according to IEC 60601-2-33. 
rms
 
We recommend that the magnetically induced deflection force for a stent composed 
of ferromagnetic material be determined at the location where the spatial gradient of 
the magnetic field is a maximum.  The magnetically induced deflection force for a 
stent composed of paramagnetic material should be determined at the location where 
the product of the magnitudes of the magnetic field and the spatial gradient of the 
magnetic field (  B   B  ) is a maximum.  (It is possible that this location is off the 
central axis of the bore of the scanner.)  The magnetically induced torque is a function 
of the field strength, and so should be measured where the static magnetic field is the 
greatest, within the bore of the magnet.  Note that the physical locations of the 
maximum torque and displacement force will almost certainly be different.  You 
should perform all testing on finished devices.   
 
Please note that for radiofrequency (RF) heating testing using the phantom described 
in ASTM F2182 or equivalent, anatomical positioning of the stent in the phantom 
does not reliably predict the implant heating in the patient.  Therefore, you should 
provide calorimetry data to demonstrate that your test conditions are applicable to 
reasonable worst-case clinical conditions for heating.  
 
Because the potential for device heating is impacted by the relationship between the 
conductive length of the device and the wavelength of the RF, higher magnetic field 
strengths do not necessarily result in worst-case test conditions for a particular device. 
Therefore, we recommend that you test your device at all field strengths for which 
you are seeking MR Conditional labeling. Given the prevalence of 1.5 T and 3.0T 
MR systems, we recommend that, at a minimum, you test your device using both of 
these systems unless you are able to provide compelling evidence that a particular 
system represents a worst-case situation for your device. If you anticipate that your 
stents will be overlapped during clinical procedures, we recommend that you consider 
the total length of overlapping stents in your determination of worst case test 
conditions and test accordingly.   
  24 Contains Nonbinding Recommendations 
 
     
There is a large variability across available MR scanners of the actual specific 
absorption rate (SAR) delivered.  In general, the actual SAR delivered is much lower 
than the value displayed on the scanner console.  Therefore, we recommend that you 
determine the actual SAR delivered to your stent during testing by calorimetry and 
report this in the labeling. 
 
We recommend that your labeling contain information for the patient and medical 
personnel about any potential hazards associated with MRI as a result of the presence 
of the implanted stent.  See Section VIII. Labeling for examples of language 
describing the MRI compatibility of stents in labeling. 
 
14. Radiopacity 
Significance 
Stent visibility using angiographic or radiographic imaging or both generally assures 
proper stent placement and allows follow-up and secondary treatment. 
 
Recommendation 
FDA recommends that you evaluate the radiopacity of your stent at the smallest 
diameter and the shortest length during the following stages in the life of the stent: 
  delivery 
  deployment, if separate from delivery 
  after implantation. 
 
We recommend that you provide a qualitative or quantitative indication of the 
visibility of the stent on real-time and plane film x-ray.  It is acceptable to use data 
from images of animal implants, in vitro phantoms, or equivalent models. 
 
15. Crush Resistance (Peripheral Indications Only) 
Significance 
Peripheral stents in some anatomic locations may experience external, non-cardiac, 
focal, or distributed loads.  These loads could cause stent deformation and, possibly, 
adverse clinical consequences. 
 
Recommendation 
FDA recommends that you demonstrate the ability of your stent to recover its desired 
size and shape after application and removal of external loads, deformations, or both.  
We recommend that you support the nature, location, and extent of all external loads 
and deformations based on the intended implantation site, for example, the carotid or 
femoral arteries.  Testing may include the application of focal loads, axially 
distributed loads, or both, depending on the target vasculature. 
 
We recommend that you report the change in unloaded stent dimensions after the 
application and removal of all of the specified loads and displacements. 
  25 Contains Nonbinding Recommendations 
 
 
16. Kink Resistance (Peripheral Indications Only) 
Significance 
Peripheral stents used in some anatomic locations will bend during normal body 
motion, such as knee flexion.  Such bends could cause stent deformation and possible 
adverse clinical consequences. 
 
Recommendation 
We recommend that you determine the smallest radius of curvature that your stent 
can withstand without kinking, and demonstrate that the stent recovers its original 
size and shape after testing.  We recommend that you support the nature, location, 
and extent of all external loads and deformations based on the intended implantation 
site, for example, the carotid or femoral arteries. 
 
17. Additional Tests for Stents Intended for In-Stent Restenosis 
Significance 
Deployment of stents within previously implanted stents to treat in-stent restenosis 
could result in increased corrosion potential, stress, fatigue, wear, coating damage, 
and particulate generation due to stent to stent interactions.   
 
Recommendation 
If you intend to label your stent for in-stent restenosis, we recommend you repeat the 
following tests within an expanded stent (i.e., with 100% overlapped stent pairs): 
  Fretting Corrosion (refer to Section A.3) 
  Stress/Strain Analysis (refer to Section B.9) 
  Fatigue Analysis (refer to Section B.10) 
  Accelerated Durability Testing (refer to Section B.11) 
  Particulate Evaluation, if appropriate for the indications for use (refer to 
Section B.12). 
 
18. Additional Tests for Stents Intended for Coronary Bifurcation Lesions 
Significance 
Stents designed for placement in coronary bifurcation lesions may be subjected to 
different loading conditions which could result in different corrosion potential, stress, 
fatigue, wear, coating damage, and particulate generation due to anatomical 
constraints and stent to stent interactions.   
 
Recommendation 
If you intend to label your stent for use in bifurcation lesions, we recommend that you 
simulate the target deployment site with a mock vessel which includes the following 
features: 
  parent vessel bend at a clinically relevant radius of curvature (as described in 
Section A. 3),  
  26 Contains Nonbinding Recommendations 
 
  a bifurcation angle representative of the most challenging anatomical situation 
likely to be encountered in clinical use, and 
  additional treatment of parent and/or side-branch vessels per expected clinical 
use, with simulated angioplasty and/or stenting if the bifurcation stent allows 
side-branch access.   
 
The selection of the radius of curvature of the mock vessel and of the bifurcation 
angle should be supported by an analysis of clinical images from representative target 
vessels or referenced literature.   
 
The following test methods should be updated to include the alternative target 
deployment site described above: 
  Fretting Corrosion (refer to Section A.3) 
  Stress/Strain Analysis (refer to Section B.9) 
  Fatigue Analysis (refer to Section B.10) 
  Accelerated Durability Testing (refer to Section B.11) 
  Particulate Evaluation (refer to Section B.12) 
  Delivery, Deployment, and Retraction (refer to Section C.2). 
 
Additionally, if the bifurcation stent allows for side-branch access, compatibility 
testing should be performed to ensure the stent does not cause balloon rupture of a 
PTCA catheter.  We recommend you evaluate the Balloon Rated Burst Pressure and 
Balloon Fatigue of PTCA catheters within your expanded stent.  For more 
information, please refer to Section IX.C. Additional Tests for Catheters Intended 
for In-Stent Restenosis or for Stent Expansion following Stent Deployment from 
the Class II Special Controls Guidance Document for Certain Percutaneous 
Transluminal Coronary Angioplasty (PTCA) Catheters.14  
 
 
C. Delivery System Dimensional and Functional Attributes 
1.  Dimensional Verification 
Significance 
Stent delivery system dimensions influence the ability of the device to track to and 
across lesions. 
 
Recommendation 
We recommend that you provide dimensional specifications and tolerances for your 
device as manufactured. At a minimum, we recommend that you report effective 
length, shaft inner and outer diameter, and crossing profile.   
The crossing profile is defined as the maximum diameter found between the proximal 
end of the mounted stent and the distal tip of the delivery system.  Testing should 
address potential differences in crossing profile that may exist in the circumferential 
                                                 
14 http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm070984.htm   
  27 Contains Nonbinding Recommendations 
 
direction.  For these situations, we recommend that you evaluate the crossing profile 
of your delivery system along different longitudinal paths (e.g., rotating test sample 
90 degrees for measurements).  We recommend that you report the crossing profile in 
the instructions for use, the outside package labeling, or both.  We recommend the 
methods described in ASTM F2081 or their equivalents. 
 
2.  Delivery, Deployment, and Retraction 
Significance 
The delivery catheter should safely and reliably deliver the stent to the intended 
location according to the instructions for use, without damage to the stent. 
 
Recommendation 
FDA recommends that you conduct testing to demonstrate that the delivery catheter 
can safely and reliably deliver the stent to the intended location and that the stent is 
not adversely affected by the delivery catheter, both during deployment and 
withdrawal.   
 
We recommend that this simulated use testing be performed by tracking the device 
through an in vitro fixture that mimics challenging in vivo physiologic and anatomic 
conditions (e.g., a tortuous path, aqueous environment), to the extent that the device 
would enter a patient in clinical use.  For coronary indications, FDA recommends the 
tortuous path described by Figure X2.4 of ASTM F2394.  For peripheral indications, 
please provide an appropriate justification for your final model, including schematics 
of the fixture and a clinically-based discussion of why it provides a sufficiently 
challenging model for device tracking.  We recommend that you conduct all testing 
on complete sterilized assemblies with mounted stents and any accessory devices that 
would be used in a typical clinical procedure (e.g., introducer or guiding catheter), 
using worst-case sizes (e.g., smallest guiding catheter ID).  We also recommend that 
you thermally equilibrate all test samples in a 37C saline bath.  You should report 
any abnormality or difficulty observed during the simulated procedure, as well as any 
damage observed on the stent, delivery system, or any of the accessory devices.  We 
recommend that you measure and report the diameter and axial location of the largest 
deflated balloon profile (including the inner member or wire).  This information can 
be used to determine the extreme dimensions of compatible accessory devices (i.e., 
minimum internal diameter), which should be identified in the labeling. 
 
It may be possible to combine Delivery, Deployment and Retraction testing with 
Particulate Evaluation (see Section IV. Non-Clinical Engineering Tests B. Stent 
Dimensional and Functional Attributes 12. Particulate Evaluation) and/or with  
Coating Integrity (see Section IV. Non-Clinical Engineering Tests C. Delivery 
System Dimensional and Functional Attributes 11. Coating Integrity), but you 
should take care to ensure that only minimal additional handling of the test samples is 
required for the coating integrity evaluation such that particulates are neither lost nor 
generated. 
 
  28 Contains Nonbinding Recommendations 
 
3.  Balloon Rated Burst Pressure (Balloon Expandable Stents Only) 
Significance 
The rated burst pressure (RBP) is the pressure at which 99.9% of balloons can survive 
with 95% confidence.  Failure of a balloon to survive at the RBP could result in 
device failure or vessel damage. 
 
Recommendation 
We recommend that you test balloons with mounted stents that are not constrained by 
any test fixture, such as tubing.  If the entire range of device sizes will have a single 
labeled RBP; we recommend that you conduct testing on the longest length of every 
balloon diameter, plus the smallest diameter at the shortest length and the largest 
diameter at the shortest length. Table 3 illustrates the recommended test matrix for a 
stent design that ranges in diameter from 2.5 to 4.0 mm and ranges in length from 8 to 
24 mm. 
 
Table 3: Stent Delivery Sizes to Test for RBP 
 
Stent  Stent Length 
Diameter  (mm) 
(mm)  8  12  18  24 
2.5  X      X 
3.0     X 
3.5     X 
4.0  X      X 
 
We recommend that you test according to the example in Table 3 for each balloon 
size with a different labeled RBP.  We recommend that you test balloons that are not 
constrained by any test fixture such as tubing, and that you inflate the balloons 
incrementally until failure. 
 
We recommend that you record as test failures any loss of: 
  integrity of the balloon, such as a rupture or leak 
  pressure due to failure of the balloon, shaft, or seals. 
 
We recommend that you record the pressure at which the device failed and the failure 
mode.  We also recommend that you calculate RBP as the pressure at which 99.9% of 
the balloons will survive with 95% confidence based on statistical analysis of the test 
data.  We recommend that you specify RBP in the device labeling. 
 
4.  Balloon Fatigue (Repeat Balloon Inflations; Balloon Expandable Stents Only) 
Significance 
Balloons on stent delivery systems are often inflated multiple times during clinical 
use.  Failure of the balloon to withstand multiple inflations could lead to device 
failure or vessel damage. 
 
  29 Contains Nonbinding Recommendations 
 
Recommendation 
FDA recommends that you determine the repeatability, to 10 inflations, of successful 
balloon inflation to the RBP.  We recommend that your sample dimensions follow the 
four corners paradigm: 
  largest diameter/longest length 
  largest diameter/shortest length 
  smallest diameter/longest length 
  smallest diameter/shortest length. 
 
We recommend that you test balloons with mounted stents that are not constrained by 
any test fixture such as tubing and that you inflate the balloons in increments until 
they reach the RBP.  For each sample we recommend that you hold the RBP for 30 
seconds (or the time specified in the instructions for use), deflate the balloon, and 
inflate it again to the RBP, for a total of 10 cycles.  Note that the number of cycles 
recommended for this testing is different from our recommendations for balloon 
catheters indicated for angioplasty (PTCA catheters).  This difference is intentional 
and reflects the likely number of inflations that would occur with use of a stent 
delivery system versus a stand-alone PTCA catheter.  We recommend that you report 
any loss of pressure, whether due to failure of the balloon, shaft, or proximal or distal 
seals, as a test failure.  We recommend that you record all failure modes, and that 
your results demonstrate that 90% of the balloons will survive the test with 95% 
confidence.  
 
5.  Balloon Compliance (Stent Diameter vs. Balloon Pressure; Balloon Expandable 
Stents Only) 
Significance 
The diameter of a deployed balloon expandable stent varies with the balloon inflation 
pressure.  A compliance chart in the labeling that relates stent diameter to balloon 
pressure guides selection of stent size to fit the target lesion.  Incorrect selection of 
stent size may lead to device failure or vessel damage.   
 
Recommendation 
FDA recommends that you test balloon sizes as illustrated in Table 3, and that you 
test multiple product lots.  We recommend that you explain why you chose the test 
sample size.  We recommend that you include data showing inflation pressure versus 
balloon diameter over the full range of recommended inflation diameters, and report 
the final results in the instructions for use, the outside package labeling, or both.  A 
graphical or tabular presentation (i.e., a compliance chart) is desirable.   
We recommend that you identify the nominal inflation pressure and RBP, as shown in 
the example below.  The compliance chart may include pressures up to (but not 
exceeding) 25% above the RBP, if you provide data and statistics demonstrating that 
99% of the balloons will not fail at the listed pressure with 95% confidence.  We also 
recommend that you describe how you performed any data rounding and show all 
instances.  Table 4 below shows an example of a compliance chart for a stent with 
  30 Contains Nonbinding Recommendations 
 
3.0 mm, 3.5 mm, and 4.0 mm diameters, with a RBP of 16 atmospheres (atm).  The 
nominal diameter occurs at 9.0 atm. 
 
Table 4:  Sample Compliance Chart for a Balloon Expandable Stent 
 
Stent Nominal Diameter  
Pressure  where x = stent inner diameter at the given pressure 
(atm)  3.0 mm Stent Inner  3.5 mm Stent Inner  4.00 mm Stent Inner 
Diameter (mm)  Diameter (mm)  Diameter (mm) 
9.0  x  x  x 
10.0  x  x  x 
11.0  x  x  x 
12.0  x  x  x 
13.0  x  x  x 
14.0  x  x  x 
15.0  x  x  x 
16.0*  x  x  x 
*RBP 
 
6.  Balloon Inflation and Deflation Time (Balloon Expandable Stents Only) 
Significance 
Balloons occlude the target vessel and obstruct blood flow while inflated.  Inflation 
and deflation times affect occlusion time.  Excessively slow inflation or deflation of a 
balloon could lead to prolonged ischemia and damage to the end organ.   
 
Recommendation 
FDA recommends that you demonstrate, using techniques recommended in your 
instruction manual (e.g., pre-dilation), that the balloon inflates and deflates within 
acceptable times, and provide the clinical basis for your acceptance criteria.  We 
recommend that you test the largest diameter at the longest balloon length, and 
evaluate which other sizes to test.  We also recommend you specify the balloon 
deflation times in your labeling.  Please observe and describe any interference with 
balloon deflation or delivery system extraction from the deployed stent. 
 
7.  Catheter Bond Strength 
Significance 
Failure of bonds in the delivery catheter could lead to device failure or vessel 
damage. 
 
Recommendation 
We recommend that you test the bond strength at locations where adhesives, thermal 
fusion, or other joining methods are used for bonding components of the delivery 
system.  Prior to evaluating tensile strength, we recommend you precondition 
catheters by tracking through a tortuous path fixture, as described above in Section 2. 
Delivery, Deployment and Retraction).  We recommend that testing demonstrate 
  31 Contains Nonbinding Recommendations 
 
that all bonds can withstand tensile forces greater than those that may be experienced 
during clinical use.  We also recommend you provide the clinical basis for your 
acceptance criteria. 
 
8.  Tip Pull Test  
Significance 
Failure of bonds in the distal tip could lead to device failure or vessel damage. 
Recommendation 
For devices with one or more joints in the distal tip (e.g., spring or nose-cone tips), 
FDA recommends that you determine the tensile force that will separate the distal tip 
from the catheter.  We recommend that you precondition catheters prior to tip pull 
testing by tracking through a tortuous path fixture, as described above in Section 2. 
Delivery, Deployment and Retraction. 
 
9.  Flexibility and Kink Test 
Significance 
Stent delivery systems may be subjected to tight angulations in tortuous vasculature 
during use.  Inability to withstand flexural forces that are typical of clinical use could 
lead to device failure or vessel damage. 
Recommendation 
FDA recommends that you conduct testing which demonstrates that the stent delivery 
system will not kink at a bend radius that is appropriate for the intended anatomy.  
We recommend that you consider wrapping the catheter around a series of mandrels 
with successively smaller radii until the catheter kinks or the lumen collapses.  We 
also recommend you provide the clinical basis for your acceptance criteria. 
 
10. Torque Strength 
Significance 
Stent delivery systems may be subjected to torsional forces during use.  Even non-
fixed wire delivery systems could be subject to torsional forces if the tip is 
inadvertently caught on a previously deployed stent, calcified lesion, etc.  Inability to 
withstand torsional forces that are typical of clinical use could lead to device failure 
or vessel damage. 
Recommendation 
FDA recommends that you measure the torque strength of the stent delivery system 
when the distal tip is not free to rotate, by rotating the proximal end of the catheter 
until failure.  We recommend that you precondition delivery systems prior to 
evaluating torque strength by tracking through a tortuous path fixture, as described 
above in Section 2. Delivery, Deployment and Retraction.  We recommend that 
you report the number of rotations to failure and the failure mode for each sample 
tested.  Additionally, we recommend that you test the delivery system in a fixture that 
  32 Contains Nonbinding Recommendations 
 
simulates the anatomy of the aortic arch and coronary arteries.  We also recommend 
you provide the clinical basis for your acceptance criteria.   
 
11. Coating Integrity 
Significance 
Unintended delamination or degradation of a coating may lessen its benefit or 
otherwise negatively impact its clinical performance.   
 
Recommendation 
FDA recommends that you address the aspects described below for any coatings 
applied to the surfaces of your product.  
 
Coating Description 
We recommend that you describe the clinical purpose and intended function of 
the coating, such as enhanced radiopacity, thromboresistance, or lubricity.   
 
We also recommend that you describe the physical structure of the coating, such 
as coating thickness, and indicate its chemical identity. 
 
Test Samples 
You should conduct all testing on the finished product subject to all 
manufacturing processes including sterilization.  You should provide a scientific 
or statistical justification for the sample size for each test.  We recommend that 
you implement a sampling plan to examine multiple lots of product (3) to assess 
both inter- and intra-lot variability. You should perform testing on sizes that 
represent four corners of the stent design (see Table 2 above) as well as an 
intermediate size. 
 
It may be possible to combine the Coating Integrity Evaluation with Delivery, 
Deployment and Retraction testing (see Section IV. Non-Clinical Engineering 
Tests C. Delivery System Dimensional and Functional Attributes 2. Delivery 
Deployment and Retraction) and/or with Particulate Evaluation (see Section IV. 
Non-Clinical Engineering Tests B. Stent Dimensional and Functional 
Attributes 12. Particulate Evaluation) but you should take care to ensure that 
only minimal additional handling of the test samples is required for the coating 
integrity evaluation such that particulates are neither lost nor generated. 
 
Interpretation of Data 
Coating integrity is considered a characterization test.  Acceptance criteria are not 
required; however, you should provide an interpretation of the data.   
 
In your coating integrity test reports you should include a detailed discussion of 
the surfaces using any practical methods to quantify defects.  This may include 
counting the number of total defects per unit area, measuring representative defect 
areas, and measuring worst-case defect areas.  You should support your 
  33 Contains Nonbinding Recommendations 
 
discussion with representative images (including worst-case) at a sufficient 
magnification to characterize the defects.  Multiple magnifications may be needed 
to visualize and adequately characterize the product.  The discussion of acceptable 
coating integrity should include a justification that the number and size of defects 
observed will not impact clinical performance. 
 
We recommend that you address the aspects described below for any coatings 
applied to the surfaces of your product.  
 
Baseline Coating Integrity 
We recommend that you conduct a visual assessment of the coating integrity on 
all appropriate surfaces of the delivery system before stent deployment to 
establish a baseline for comparison to coating characteristics after testing 
performed under other conditions.  We recommend that you appropriately 
quantify characteristics such as continuity and voids in the coating, as described 
above.     
 
Simulated Use Coating Integrity 
We also recommend that you evaluate the coating integrity after simulated use, 
via visual assessment.  Devices should be tracked through a tortuous path fixture 
(as described above in Section 2. Delivery, Deployment and Retraction) and 
then expanded in air or an aqueous medium to the maximum labeled diameter 
described in the Instructions for Use prior to visual inspection.  You should also 
assess the impact of simulated use on the functional aspects of the coating. 
 
12. Stent Securement for Unsheathed Stents 
Significance 
Dislodgment of the stent prior to deployment can result in stent embolization.  Stents 
without sheaths may dislodge if they catch on tortuous anatomy, guide catheters, or 
other devices. 
 
Recommendation 
FDA recommends that you measure the force that will dislodge the stent from the 
delivery system under clinically relevant conditions.  We recommend that the test 
simulate the intended use, including insertion through a tortuous path that simulates 
the vasculature proximal to and including the lesion site.  We recommend that the 
tortuous path be sized appropriately for the stent size being tested.  We recommend 
that you submit a photo, diagram, or description of the tortuous path, including 
dimensions.  For coronary indications, FDA recommends the tortuous path described 
by Figure X2.4 of ASTM F2394.  For peripheral indications, please provide the 
clinical basis for your final model.  We recommend that the stent sizes tested 
represent the worst case stent securement for your design.  We recommend that you 
explain why your results are applicable to all sizes of your stent, including those not 
tested for stent securement. 
 
  34 Contains Nonbinding Recommendations 
 
FDA recommends that you address the modes of dislodgement as described below: 
 
Dislodgement by Forward Motion 
Advancing a stent delivery system across a tight lesion could result in stent 
dislodgement.  We recommend testing the stent by passing it through a simulated 
tight lesion in the tortuous path. 
 
Dislodgement by Reverse Motion 
Withdrawing a stent delivery system into a guiding catheter, arterial sheath, or 
hemostasis valve could result in stent dislodgement.  We recommend testing the 
stent by attempting to withdraw the un-deployed stent into a guide catheter or 
other opening of the smallest size for an accessory device recommended in the 
instructions for use. 
 
D. Shelf Life 
Significance 
Aging can potentially affect the performance of the materials of construction for the 
stent and delivery system.   
 
Recommendation 
We recommend that shelf life testing address package integrity to ensure sterility, as 
well as stable device functionality over the expected life cycle.   
 
To evaluate device functionality, we recommend that you repeat the following bench 
tests on aged devices:   
  Stent Dimensional Verification (refer to Section B.1) 
  Stent Foreshortening* (refer to Section B.3) 
  Radial Outward Force* (refer to Section B.7) 
  Particulate Evaluation (refer to Section B.12) 
  Delivery System Dimensional Verification (refer to Section C.1) 
  Delivery, Deployment, and Retraction (refer to Section C.2) 
  Balloon Rated Burst Pressure (refer to Section C.3) 
  Balloon Fatigue (refer to Section C.4) 
  Balloon Compliance (refer to Section C.5) 
  Balloon Inflation and Deflation Time (refer to Section C.6) 
  Catheter Bond Strength (refer to Section C.7) 
  Tip Pull Test (refer to Section C.8) 
  Flexibility and Kink Test (refer to Section C.9) 
  Torque Strength (refer to Section C.10) 
  Coating Integrity (refer to Section C.11) 
  35 Contains Nonbinding Recommendations 
 Stent Securement for Unsheathed Stents (refer to Section C.12)
*only repeat testing on aged stents if self-expanding
Additional tests may be recommended for certain devices, depending on their design, 
materials (alloys), or manufacturing processes.  
We recommend that you provide the protocol used for your shelf life testing, the 
results of the testing, and the conclusions drawn from your results.  If you use devices 
subjected to accelerated aging for shelf life testing, we recommend that you specify 
the way in which the device was aged.  Since stent delivery systems contain 
polymeric materials, you should plan to conduct testing on real-time aged samples to 
confirm that accelerated aging is reflective of real-time aging.  This testing should be 
conducted in parallel with PMA review and approval, with results submitted in a 
post-approval annual report.   
E. Biocompatibility
Significance 
Stents and delivery systems contain patient-contacting materials, which when used 
for their intended purpose, i.e., contact type and duration, may induce a harmful 
biological response. 
Recommendation 
We recommend that you determine the biocompatibility of all patient-contacting 
materials present in your device.  If your materials are identical in composition and 
processing methods to materials with a history of successful use in cardiovascular 
product applications, you may reference the appropriate literature or previous testing 
experience.  We recommend that you test novel materials, i.e., those with no history 
of successful prior use according to the methods in the FDA-recognized version of 
relevant ASTM, USP, and ISO standards.  In addition, we recommend that you 
follow the guidance Use of International Standard ISO-10993, 'Biological 
Evaluation of Medical Devices Part 1: Evaluation and Testing15 to identify the 
types of tests that should be considered.  
Differences in formulation, processing or sterilization that could affect 
biocompatibility of the final product may warrant additional biocompatibility testing. 
Sample Preparation 
It is important to understand how the test samples compare to the final sterilized 
product.  For biocompatibility testing conducted using extraction samples, we 
recommend that you: 
 determine the appropriate amount of test material as outlined in ISO 10993-12
or an equivalent method, using surface area to extractant volume ratios (mass
15 https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm348890.pdf
36 Contains Nonbinding Recommendations 
to extractant volume ratios should only be used if surface area cannot be 
calculated) 
 use both polar and nonpolar extractants
 describe the condition of the extraction vehicle (e.g., color, presence of any
particles)
 explain any changes in the post-extraction vehicle (compared to pre-
extraction)
 describe the details of storage conditions, if applicable.
If extraction samples are not used immediately, we recommend that you follow the 
storage conditions described in ISO 10993-12 or an equivalent method.  We also 
recommend that you explain how storage does not affect your test results. 
Stents 
Because stents are implanted products in contact with cardiovascular tissue and 
circulating blood, with a permanent duration of contact (>30 days), we recommend 
the following tests be considered:  
 cytotoxicity
 sensitization (guinea pig maximization with both polar and non-polar extracts)
 irritation (or intracutaneous reactivity)
 acute systemic toxicity
 material-mediated pyrogenicity
 hemocompatibility [hemolysis, in vivo thrombogenicity, and direct contact
complement activation (C3a and SC5b-9)]
 sub-chronic toxicity
 genotoxicity (bacterial reverse mutation assay, mammalian cell in vitro assay,
and in vivo cytogenetics assay in rodents)
 chronic toxicity
 implantation
 carcinogenicity.
Delivery Systems 
Because delivery catheters are externally communicating products in contact with 
cardiovascular tissue and circulating blood, with a temporary duration of contact (<24 
hrs), we recommend the following tests be considered:  
 cytotoxicity
 sensitization (guinea pig maximization with both polar and non-polar extracts)
 irritation (or intracutaneous reactivity)
 acute systemic toxicity
 material-mediated pyrogenicity
37 Contains Nonbinding Recommendations 
 hemocompatibility [hemolysis, in vivo thrombogenicity, and direct contact
complement activation (C3a and SC5b-9))
 genotoxicity (bacterial reverse mutation assay, mammalian cell in vitro assay,
and in vivo cytogenetics assay in rodents).
Additional testing may be requested to fully characterize the toxicology profile, 
depending on the materials of use. 
Additional Considerations 
 Cytotoxicity
We recommend that extractions be conducted at 37C for 24 hours using a vehicle 
with both mammalian cell culture media (MEM) and 5% serum, as these 
materials will allow for extraction of both polar and nonpolar constituents from 
the test sample.   
 Sensitization (Guinea Pig Maximization Method)
We recommend that test reports confirm that all female animals used in the 
testing are not pregnant, as pregnancy can reduce the ability of a female animal to 
detect a sensitization response.   
We recommend either that you run concurrent controls, or that the test laboratory 
run controls within 3 months of the test samples.  We also recommend you 
provide protocols and results from positive control testing to confirm that you 
used the same methods for both the positive control testing and the test samples. 
 Hemocompatibility
For blood-contacting devices (regardless of contact duration), we recommend that 
you consider hemolysis, immunology (complement activation), and in vivo 
thromboresistance.   
Immunology testing should appropriately address the various complement 
activation pathways.  We recommend that you assess in vitro C3a and SC5b-9 
fragment activation using standard testing methods, such as those outlined in 
ASTM F2065-00e116 and ASTM F1984-99 (2003)17, or an equivalent method.  
Alternatively, you may provide a rationale for omitting this testing, if all the 
materials used in the formulation and processing of the device have a history of 
previous use in blood-contacting devices with similar contact duration. 
In addition, you may assess in vivo thrombogenicity during preclinical animal 
testing in lieu of a separate canine in vivo thrombogenicity test.  If a 4 hour canine 
in vivo thrombogenicity study is needed (e.g., due to the use of novel materials 
never before used in a medical devices or questionable findings from the vascular 
16 ASTM F2065-00e1 Alternative Pathway Complement Activation in Serum by Solid Materials. 
17 ASTM F1984-99 (2003) Whole Complement Activation in Serum by Solid Materials. 
38 Contains Nonbinding Recommendations 
animal studies), we recommend the study be conducted in a venous, 
unheparinized model. 
 Material-mediated Pyrogenicity
We recommend that you assess pyrogenic responses to chemical leachants over 
the duration of device contact with the patient.  We recommend that you assess 
material-mediated pyrogenicity using traditional biocompatibility extraction 
methods, such as those outlined in the USP 28 <151> Rabbit Pyrogen Test (e.g., 
50C for 72 hours; 70C for 24 hours; or 120C for 2 hours) or an equivalent 
method.  You should consider that temperatures above 37C may result in 
toxicities not representative of the final product. 
 Nickel ion release
For devices containing nitinol, we recommend that you consider the potential for 
nickel ion release from your device.  Specifically, if you cannot demonstrate that 
your nitinol device exhibits sufficient corrosion resistance as well as an adequate 
passivation layer, we recommend that you quantify nickel ion release from your 
device over time.  Testing can be performed by measuring concentrations of 
nickel leached from the device into a fluid with physiologic temperature and pH. 
V. Labeling
General labeling requirements for medical devices are described in 21 CFR Part 801.
Additional information may be obtained from Device Advice.18  You must submit all
proposed labeling in your PMA [21 CFR 814.20(b)(10)].
FDA recommends that labeling for extracranial intravascular stents include the sections
described below.  Some of these recommendations may also be relevant to covered, drug-
eluting, and biodegradable stents; however, FDA recommends additional labeling, not
described in this document, for those devices.  The Interventional Cardiology Devices
Branch and the Peripheral Vascular Devices Branch are available to discuss labeling for
those stents and indications.
A. Device Description
We recommend that you describe the stent and delivery catheter, including the stent
material, whether the stent is balloon expandable or self-expanding, etc.  You should
consider including a table with the following attributes, as appropriate:
 available stent diameters and lengths
 guiding catheter/sheath compatibility
 deployment and RBPs
 percent stent free area.
18 http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/default.htm  
39 Contains Nonbinding Recommendations 
 
We recommend that you describe any ancillary or accessory devices that are packaged 
with your stent system when no separate labeling is available.  An example would be a 
description of an embolic protection system that is packaged with your stent delivery 
system.  You may add additional information where appropriate. 
 
B. Indications for Use 
We recommend that proposed labeling reflect the precise indications for use statement 
that is the subject of the application.  The general statement of the Indications for Use 
identifies the target population in which sufficient valid scientific evidence has demonstrated 
that the device as labeled will provide clinically significant results and at the same time does 
not present an unreasonable risk of illness or injury associated with the use of the device. 
 
C. Contraindications 
We recommend that you include contraindications to the use of the device.  
Contraindications describe situations in which the device should not be used because the 
risk of use clearly outweighs any possible benefit. 
 
D. Warnings 
We recommend that you include an appropriate warning if there is reasonable evidence 
of an association of a serious hazard with the use of the device.  A causal relationship 
need not have been proved.   
 
We believe a warning is also appropriate when the device is commonly used for a disease 
or condition for which there is a lack of valid scientific evidence of effectiveness for that 
disease or condition or use of the device is associated with a serious risk or hazard. 
 
We also recommend that you include warnings to address the: 
 
  need for appropriate anticoagulation or antiplatelet therapy or both
 
  recommendation that when multiple stents are used, they should be of similar 
composition
 
  fact that long-term outcomes following repeat dilatation of endothelialized stents are 
unknown. 
 
E. Precautions 
You should include as precautions information regarding any special care physicians or 
others should exercise for the safe and effective use of the device.  Additionally, you should 
include any limitations on the use of a device for reasons including, but not limited to: 
  lack of long-term safety and effectiveness data 
  lack of safety and effectiveness data for special patient populations 
  need for appropriate physician training 
  anatomical or physiological limitations on the effectiveness of the device. 
 
  40 Contains Nonbinding Recommendations 
Stent handling, stent placement, stent system removal, and any post-implant precautions 
are appropriate for inclusion in this section.  Additionally, you should address length of 
follow-up or use in special patient populations, for example: 
The safety and effectiveness of the ABC (coronary or peripheral) stent system has not 
been established in patients beyond x (months/years) of follow-up. 
or 
The safety and effectiveness of the XYZ coronary stent system has not been 
established in patients with recent acute myocardial infarction. 
F. MR Environment
We recommend you follow the labeling guidelines given in Guidance for Industry 
and FDA Staff:  Establishing Safety and Compatibility of Passive Implants in 
the MR (Magnetic Resonance) Environment19 
Overlapping Stents or Stents with Fractured Struts 
In addition to the labeling recommendations in the Guidance for Industry and FDA 
Staff:  Establishing Safety and Compatibility of Passive Implants in the MR 
(Magnetic Resonance) Environment,  FDA recommends that your labeling also 
describe whether you determined the effect of heating in the MRI environment for 
overlapping stents or stents with fractured struts.  If you have not determined what 
those effects are, we recommend that your labeling reflect this, for example: 
The effect of heating in the MRI environment for overlapping stents or stents with 
fractured struts is not known. 
G. Overview of Clinical Studies
You should provide a narrative description of the pivotal study or studies and any
supporting or feasibility studies relevant to the stent.  The narrative should be brief, and
should include the following information for each study:
 whether the study was a pivotal, supporting, or feasibility study
 the design of the study, including any randomization, blinding, and the control or
controls used
 the number of patients enrolled
 the number of investigational sites both inside the United States (US) and outside
the United States (OUS)
 the primary study endpoint or endpoints
 the amount of available follow-up
 the total planned follow-up.
19 http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm107705.htm
41 Contains Nonbinding Recommendations 
H. Adverse Events
Observed Adverse Events 
You should provide a brief narrative statement about the source or sources of the 
adverse event experience followed by results in a tabular format.  In the table, we 
recommend that you present adverse events using a per protocol (also known as an 
evaluable) approach.   
In this approach, the numerator consists of the number of patients presenting with the 
adverse event during or before the analysis window.  For each adverse event, the 
denominator consists of: 
The number of  Any patients not evaluated during the analysis 
patients evaluated  +  window, but that had the specified adverse 
during the analysis  event between treatment and the analysis 
window  window 
The numerator consists of the number of patients presenting with the adverse event 
during or before the analysis window. 
You may also use an alternative approach known as intent-to-treat analysis, in 
which any patients not evaluated during the analysis window are assumed to have had 
an adverse event.  If your trial involves substantial numbers of crossover patients, an 
intent-to-treat analysis may be more appropriate.  In this analysis, adverse events 
would be assigned to the original treatment group regardless of actual treatment 
received or time at which the adverse event occurred. 
You should include an adverse events table that captures data through the longest 
available follow-up for the study.  You should also provide protocol definitions for 
adverse events as footnotes, or a reference to definitions included with the Principal 
Safety and Effectiveness Table. 
We have provided a list of suggested elements for inclusion, below.  Additional 
elements may be appropriate given the specific vessel or vessels to be stented. 
Coronary Indications 
You should separate in-hospital events from out-of-hospital events (through X 
days or months), for categories such as: 
 major adverse cardiac events (MACE), which includes:
o death
o Q-wave myocardial infarction (MI)
o non-Q-wave MI
o emergent coronary artery bypass grafting (CABG)
o target lesion revascularization (TLR)
42 Contains Nonbinding Recommendations 
 target lesion failure (TLF)
 target vessel failure (TVF)
 target vessel revascularization (TVR)
 TVR, non-TLR
 stent thrombosis (acute, subacute, late)
 cerebro-vascular accident (CVA)
 bleeding complications
 vascular complications
Peripheral Indications 
You should separate events at specific time points (e.g. 30 days, 1 year) and 
cumulative events for categories such as: 
 major adverse event (MAE)  may be study specific
o death
o stroke
o Q-wave MI (in-hospital)
o non-Q-wave MI
o end organ injury or ischemia or both
o TLR
o target limb amputation
 TVF
 TVR
 TVR, non-TLR
 stent thrombosis (acute, subacute, late)
 bleeding complications
o access site
o non-access site
 vascular complications
o perforation
o aneurysm
o pseudo-aneurysm
o dissection
Potential Adverse Events 
You should include potential adverse events associated with stenting of the intended 
coronary or peripheral vessel or vessels. 
43 Contains Nonbinding Recommendations 
I. Clinical Studies
You should include additional specifics about the clinical studies described in the section
titled Overview of Clinical Studies, above.  We suggest the following format:
Purpose/Objective 
You should state the intent of the study, including the primary endpoint or endpoints. 
Conclusions 
You should briefly state the study outcome or outcomes. 
Design 
You should describe your study design.  The following is a partial list of elements 
that may be appropriate to your design:  
 whether the design is randomized or non-randomized
 whether the study is controlled
 which type of controls were used
 if the study results were compared to a performance goal
 how any performance goals were derived.
You should also describe the success criteria for the trial (i.e., superiority or non-
inferiority when compared to the control). 
You should include a brief description of patient entry criteria, such as: 
 vessel location
 vessel size
 vessel type, (i.e., de novo or restenotic)
 type of evaluations (clinical, telephone, angiographic/intravascular ultrasound
follow-up).
Demographics 
You should describe characteristics of your patient populations that could affect the 
results of the study, including: 
 age
 race
 gender
 percentage of smokers
 incidence of hyperlipidemia
 previous MI
 diabetes
44 Contains Nonbinding Recommendations 
 any other important covariates.
Methods 
You should describe any use of a Clinical Events Committee, a Data and Safety 
Monitoring Board, and/or a core laboratory for adverse event adjudication, as 
appropriate. 
Results 
You should briefly describe the results of the study, including whether the primary 
endpoint or endpoints were met, for example: 
The X stent demonstrated a lower rate of TVF as compared to the control group 
(X% vs. Y%, P<0.001). 
You should refer to the Principal Safety and Effectiveness Table, which is described 
in the next section of this guidance. 
J. Principal Safety and Effectiveness Table
We recommend that you present the clinical outcomes in a tabular format as
effectiveness measures and safety measures, separately or combined.  Your data
presentation should follow the same approach used for adverse event reporting (for
example, per protocol or intent-to-treat).  You should include protocol definitions for
terms used in the table.
You should provide Kaplan-Meier estimates for relevant endpoints in your safety and
effectiveness table, which may include, but are not limited to:
 MACE-free survival
 MAE-free survival
 TVF-free survival
 TVR-free survival
 TLR-free survival
 primary, primary assisted, and secondary patency survival.
In some instances, it may be appropriate to provide a graphical presentation of the most 
appropriate Kaplan-Meier survival endpoints (see examples of these endpoints below) 
and accompanying life tables.  We believe that statistical comparisons between groups, as 
presented in a Kaplan-Meier presentation, are only appropriate for randomized trials.  
The review branches are available to advise you on this issue.   
Examples of Kaplan-Meier survival endpoints 
 Freedom from MACE for coronary and peripheral stenting studies
 
 Patency survival for peripheral stenting studies
45 Contains Nonbinding Recommendations 
If you provide a survival graph, it should include error bars representing a standard error 
(SE) of  1.5.  The scale should either begin on the y-axis at a value greater than zero  
we recommend using a value around 50 - 60%  or indicating a break in the scale to 
illustrate the differences in survival curves, if applicable. 
Updates to Principal Safety and Effectiveness Table 
For some devices, updates to the Principal Safety and Effectiveness Table to reflect 
additional clinical follow-up beyond the primary follow-up interval are identified as a 
condition of PMA approval.  In this case, the updated labeling should be submitted as 
a PMA supplement.  
If such an update is not listed as a condition of approval, you may provide the 
updated labeling in your annual report, as long as the updated information is based on 
the endpoints and follow-up schedule prospectively defined in your clinical study 
protocol.  For updates that relate to new indications, see 21 CFR 814.39.  The 
labeling should indicate which data were added or updated after the initial device 
approval. 
If clinical results in the updates raise a safety or effectiveness concern when 
compared to the initial results of your study, we recommend that you update the 
labeling to reflect this new information. 
K. Patient Selection and Treatment
We recommend that this section provide information related to individualization of
treatment.
L. Directions for Use
You should include directions for proper preparation and use of the device in this section
of the labeling.  If multiple delivery systems are available, you should clearly indicate
differences specific to the delivery system.  An example would be to indicate the
difference between an over-the-wire (OTW) and a rapid exchange (RX) delivery system.
Compliance Chart (Balloon Expandable Stents Only) 
Pre-mounted Balloon Expandable Stents 
You should include a compliance chart that provides the average stent inner 
diameter following deployment at various pressures derived from bench testing.  
You should display the data as determined from testing.  However, if you round 
the data, you should footnote the chart to indicate that the data is rounded.  We 
recommend the format presented in Table 4 (see Section IV.  Non-Clinical 
Engineering Tests, B.  Stent Dimensional And Functional Attributes, 4.  
Recoil For Balloon Expandable Stents). 
46 Contains Nonbinding Recommendations 
Percent Foreshortening (Self-Expanding Stents Only) 
You should provide a table that shows: 
 vessel lumen diameter
 unconstrained stent diameter
 percent foreshortening.
If you base your values on mathematical calculations, you should indicate this in a 
footnote to the table.  See Section IV.  Non-Clinical Engineering Tests, B.  Stent 
Dimensional And Functional Attributes, 3.  Foreshortening, for information on 
testing stent percent foreshortening. 
M. Patient Materials
You should provide all patient materials, such as the patient guide and implant card, that you
will make available.  See also Guidance on Medical Device Patient Labeling,20
For MR Conditional stents, we recommend you include the bulleted points from the
Guidance for Industry and FDA Staff:  Establishing Safety and Compatibility of Passive
Implants in the MR (Magnetic Resonance) Environment.  In addition, we recommend
you include the following:
the appropriate MR safety icon and term from ASTM F250321

if applicable, a statement similar to the following:  Patients with the device may

safely undergo MRI for (insert appropriate term: "Normal Operating Mode" or
"First Level Controlled Operating Mode") of the MR System as defined in IEC
60601-2-3322
a statement about the image artifact

a recommendation that patients register the conditions under which the implant can

be scanned safely with the MedicAlert Foundation (www.medicalert.org) or
equivalent organization.
20 http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm070782.htm
21 ASTM F2503 Standard Practice for Marking Medical Devices and Other Items for Safety in the Magnetic 
Resonance Environment 
22 IEC 60601 Medical electrical equipment  Part 2-33: Particular requirements for the safety of magnetic resonance
equipment for medical diagnosis 
47  
Appendix A: Test Summary Checklist
  
(continued on next page) 
 
Sizes Tested  Test Method or 
Accept/Reject 
Test  and Sample  Standard  Results
Criteria 
Sizes  Reference 
  Material Composition         
Material  Shape Memory and Superelasticity         
Characterization  Mechanical Properties         
Corrosion Resistance         
  Dimensional Verification
Stent  Percent Surface Area of the Stent         
Dimensional and 
Foreshortening         
Functional 
Recoil for Balloon Expandable Stents         
Attributes 
Stent Integrity         
Radial Stiffness and Radial Strength         
Radial Outward Force         
Stress/strain analysis         
Fatigue Analysis         
Accelerated Durability Testing         
Particulate Evaluation         
MRI Safety and Compatibility         
Radiopacity         
Coating Durability (coated stents only)         
Crush Resistance (peripheral indications only)         
Kink Resistance (peripheral indications only)         
 
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Appendix A: Test Summary Checklist   
(continued from previous page)
Sizes Tested  Test Method or 
Accept/Reject 
Test  and Sample  Standard  Results
Criteria 
Sizes  Reference 
  Dimensional Verification         
Delivery System 
Delivery, Deployment, and Retraction         
Dimensional and 
Balloon Rated Burst Pressure (balloon        
Functional 
expandable stents only) 
Attributes 
Balloon Fatigue (balloon expandable stents        
only) 
Balloon Compliance (Stent Diameter vs.        
Balloon Pressure) (balloon expandable 
stents only) 
Balloon Inflation and Deflation Time        
(balloon expandable stents only) 
Catheter Bond Strength         
Tip Pull Test         
Flexibility and Kink Test         
Torque Strength         
Coating Integrity         
Stent Securement for Unsheathed Stents         
  Packaging         
Shelf Life 
Stent Dimensional Verification         
Stent Foreshortening         
Stent Recoil         
Particulate Evaluation         
Delivery System Dimensional Verification         
Page 49   
Delivery, Deployment, and Retraction          
Balloon Rated Burst Pressure          
Balloon Fatigue          
Balloon Compliance          
Balloon Inflation and Deflation Time         
Catheter Bond Strength          
Tip Pull Test          
Flexibility and Kink Test         
Torque Strength         
Coating Integrity         
Stent Securement for Unsheathed Stents          
Biocompatibility  Biocompatibility         
Page 50   
Appendix B: Applicable Standards 
A list of FDA-recognized standards is available at 
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/search.cfm 
ISO Standard 
10993 Biological Evaluation of Medical Devices 
 
IEC Standard 
IEC 60601 Medical electrical equipment  Part 2-33: Particular requirements for the safety of 
magnetic resonance equipment for medical diagnosis 
 
 
 
ASTM Standards 
F138 Standard Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless 
Steel Bar and Wire for Surgical Implants 
F1984 Whole Complement Activation in Serum by Solid Materials 
F2004 Standard Test Method for Determination of Transformation Temperature of Nickel-
Titanium Alloys by Thermal Analysis 
F2065 Alternative Pathway Complement Activation in Serum by Solid Materials 
F2079 Standard Test Method for Measuring Intrinsic Elastic Recoil of Balloon expandable 
Stents 
F2081 Standard Guide for Characterization and Presentation of the Dimensional Attributes of 
Vascular Stents 
F2082 Standard Test Method for Determination of Transformation Temperature of Nickel-
Titanium Shape Memory Alloys by Bend and Free Recovery 
F2129 Standard Test Method for Conducting Cyclic Potentiodynamic Polarization 
Measurements to Determine the Corrosion Susceptibility of Small Implant Devices 
F2182 Standard Test Method for Measurement of Radio Frequency Induced Heating Near 
Passive Implants During Magnetic Resonance Imaging 
F2394 Standard Guide for Measuring Securement of Balloon Expandable Vascular Stent 
Mounted on Delivery System 
F2503 Standard Practice for Marking Medical Devices and Other Items for Safety in the 
Magnetic Resonance Environment 
G71 Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes 
 
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