Contains Nonbinding Recommendations 
Metal Expandable Biliary Stents - 
Premarket Notification (510(k)) 
Submissions 
Guidance for Industry and 
Food and Drug Administration Staff 
Document issued on July 27, 2019. 
 
The draft of this document was issued on July 18, 2018. 
 
This document supersedes Guidance for the Content of Premarket 
Notifications for Metal Expandable Biliary Stents, issued on February 5, 
1998. 
 
For questions about this document, contact DHT3A: Division of Renal, Gastrointestinal, Obesity, 
and Transplant Devices at (301)-796-7030. 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Devices and Radiological Health 
 
  Contains Nonbinding Recommendations 
Preface 
Public Comment 
 
You may submit electronic comments and suggestions at any time for Agency consideration to 
https://www.regulations.gov. Submit written comments to the Dockets Management Staff, Food 
and Drug Administration, 5630 Fishers Lane, Room 1061, (HFA-305), Rockville, MD 20852. 
Identify all comments with the docket number FDA-2018-D-1771. 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. You may also send an e-mail request to 
CDRH-Guidance@fda.hhs.gov to receive a copy of the guidance. Please use the document 
number 1500070 to identify the guidance you are requesting.   
 
  Contains Nonbinding Recommendations 
Table of Contents 
I.  Introduction .......................................................................................................................... 1 
II.  Background .......................................................................................................................... 1 
III.  Scope .................................................................................................................................... 2 
IV.  Definitions............................................................................................................................ 2 
V.  Premarket Submission Recommendations ........................................................................... 3 
A.  Device Description .............................................................................................................. 3 
B.  Predicate Comparison .......................................................................................................... 3 
C.  Biocompatibility .................................................................................................................. 4 
D.  Sterility ................................................................................................................................. 5 
E.  Shelf Life and Packaging ..................................................................................................... 6 
F.  Magnetic Resonance (MR) Compatibility for Passive Implants ......................................... 7 
G.  Non-Clinical Bench Testing ................................................................................................ 7 
(1)  Stent Corrosion Resistance .......................................................................................... 8 
(2)  Stent Dimensional and Functional Attributes ............................................................. 9 
(3)  Stent Delivery System (SDS) Dimensional and Functional Attributes ..................... 12 
H.  Clinical Performance Testing ............................................................................................ 17 
I.  Labeling ............................................................................................................................. 18 
(1)  Display of Common Name and Trade Name ............................................................ 19 
(2)  Device Description .................................................................................................... 19 
(3)  Contraindications ....................................................................................................... 19 
(4)  Warnings ................................................................................................................... 19 
(5)  Precautions ................................................................................................................ 20 
(6)  MRI Safety Information ............................................................................................ 20 
(7)  Overview of Clinical Studies .................................................................................... 21 
(8)  Potential Adverse Events ........................................................................................... 21 
(9)  Directions for Use ..................................................................................................... 21 
(10) Patient Labeling ......................................................................................................... 22 
Appendix A: Example Test Summary Table ................................................................................ 23 
 
 
  Metal Expandable Biliary Stents - 
Premarket Notification (510(k)) 
Submissions 
Guidance for Industry and 
Food and Drug Administration Staff 
This guidance represents the current thinking of the Food and Drug Administration (FDA or 
Agency) on this topic. It does not establish any rights for any person and is not binding on 
FDA or the public. You can use an alternative approach if it satisfies the requirements of the 
applicable statutes and regulations. To discuss an alternative approach, contact the FDA staff 
or Office responsible for this guidance as listed on the title page.  
I.  Introduction 
This guidance document provides recommendations for 510(k) submissions for metal 
expandable biliary stents and their associated delivery systems. These devices are intended to 
provide luminal patency of the biliary tree for palliation of malignant strictures. FDA updated 
this guidance to reflect current review practices. 
For the current edition of the FDA-recognized standard(s) referenced in this document, see the 
FDA Recognized Consensus Standards Database.1 For more information regarding use of 
consensus standards in regulatory submissions, please refer to FDA guidance titled Appropriate 
Use of Voluntary Consensus Standards in Premarket Submissions for Medical Devices.2 
 
FDA's guidance documents, including this guidance, do not establish legally enforceable 
responsibilities. Instead, guidances describe the Agencys 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 guidance means that something is suggested or 
recommended, but not required. 
II.  Background 
Since 1998, FDA has placed limitations on substantial equivalence determinations for biliary 
stents pursuant to section 513(i)(1)(E) of the Federal Food, Drug, and Cosmetic Act (FD&C 
                                                 
1 Available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/search.cfm. 
2
 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/appropriate-use-voluntary-consensus-
standards-premarket-submissions-medical-devices.  
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Act). For each, FDA determined that there is a reasonable likelihood that the device will be used 
in the vascular system, which is an intended use not identified in the proposed labeling, and that 
such use could cause harm. This is due to a lack of safety and effectiveness data, including 
clinical data, about the use of biliary stents in the vasculature. This includes safety (failure 
modes) and effectiveness concerns specific to the vascular use of stents that are not assessed for 
biliary applications, e.g., vascular restenosis, stent fracture if placed across a joint, and long-term 
fatigue testing. While metallic stents have since been approved for specific cardiovascular 
indications, the Agency continues to have safety and effectiveness concerns about use of biliary 
stents for vascular applications, unless the device has also been approved for a vascular 
indication through a separate premarket approval application. Therefore, in most cases, FDA 
continues to place limitations on substantial equivalence determinations for biliary stents (see 
Sections V.I(1) Display of Common Name and Trade Name and V.I(4) Warnings), and 
modifications to biliary stents (including the stent delivery system) are not eligible to be 
reviewed under the Special 510(k) paradigm. 
This document supplements other FDA documents regarding the specific content requirements 
and recommendations of a premarket notification (510(k)) submission. You should also refer to 
21 CFR 807.87 and FDAs guidance, Format for Traditional and Abbreviated 510(k)s.3 
III.  Scope 
The scope of this guidance is limited to metal expandable biliary stents regulated under 21 CFR 
876.5010 (Biliary catheter and accessories) and with product code FGE (Catheter, Biliary, 
Diagnostic). This guidance applies only to biliary stents indicated for palliation of malignant 
strictures in the biliary tree. It does not apply to biliary stents indicated to treat benign strictures 
or stents intended to be used in the vasculature, tracheal/bronchial tubes, or other gastrointestinal 
anatomy. 
IV.  Definitions 
For the purposes of this guidance, the following definitions are utilized: 
Biliary stent: An expandable biliary catheter, constructed either wholly or partially of metal, that 
may be uncovered, partially covered, or fully covered. The biliary stent is implanted in the 
biliary tree and used to provide palliation of malignant strictures. 
Balloon expandable stent: A biliary stent that 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 biliary stent that expands automatically after being released from a 
stent delivery system (e.g., a catheter); i.e., it does not require balloon inflation or other 
                                                 
3 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/format-traditional-and-abbreviated-
510ks-guidance-industry-and-fda-staff. 
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  Contains Nonbinding Recommendations 
mechanical assistance to expand. The self-expanding quality can result from material properties, 
geometry, or both. 
Stent delivery system (SDS): A system that delivers a biliary stent to a target site within the bile 
duct and then deploys the stent. A stent delivery system for a balloon expandable stent consists 
of a balloon catheter. Self-expanding stent delivery systems do not typically include a balloon. 
V.  Premarket Submission Recommendations 
A.  Device Description 
We recommend that you identify your device using the regulation and product code described in 
Section III above. For each model of biliary stent you propose to market, you should include the 
following information: 
  labeled diagram, photograph, or schematic drawing; 
  stent specifications including the length and diameter; 
  description and diagram of the stent geometry (e.g., strut width and thickness, or wire 
diameter of stent); 
  a detailed description of the SDS, including the working length, how the stent is 
delivered, as well as identification and description of any other devices provided with the 
stent. You should indicate whether the stent is to be placed endoscopically or 
percutaneously; and  
  an explanation if any of the device components are disposable or reusable. 
B.  Predicate Comparison 
For devices reviewed under the 510(k) process, manufacturers must compare their new device to 
a similar legally marketed predicate device to support its substantial equivalence (section 513(i) 
(21 U.S.C. 360c(i)) of the FD&C Act; 21 CFR 807.87(f)). This comparison should provide 
information to show how your device is similar to and different from the predicate. Side by side 
comparisons, whenever possible, are desirable. See Table 1 below for an example of how this 
information may be organized.  
   
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Table 1: Example of a Device and Predicate Comparison 
CHARACTERISTIC  DEVICE  PREDICATE DEVICE 
510(k) number  This submission  Kxxxxxx 
Indications for use 
   
statement 
Expansion method     
Stent material     
Method of introduction     
Sterility     
Delivery system length     
Stent lengths     
Stent diameters     
Strut length:   Strut length:  
Stent geometry  Strut width:  Strut width: 
Woven cell dimensions:  Woven cell dimensions: 
Delivery system profile     
Performance specifications 
(see Section V.G below of     
this guidance) 
C.  Biocompatibility 
Significance: Biliary stents contain patient-contacting materials, which, when used for their 
intended purpose (i.e., contact type and duration), may induce a harmful biological response. 
Recommendation: You should determine the biocompatibility of all patient-contacting 
components in your biliary stent and SDS. If your device is identical in composition and 
processing to biliary stents and/or SDSes with a history of successful use, you may reference 
previous testing experience or literature, if appropriate. For some device materials, it may be 
appropriate to provide a reference to either a recognized consensus standard, or to a Letter of 
Authorization (LOA) for a device Master File (MAF). 
If you are unable to identify a legally marketed predicate device with similar location/duration of 
contact and intended use that uses the same materials and manufacturing process as used in your 
device, we recommend you conduct and provide a biocompatibility risk assessment. The 
assessment should explain the relationship between the identified biocompatibility risks, the 
information available to mitigate the identified risks, and identify any knowledge gaps that 
remain. You should then identify any biocompatibility testing or other evaluations that were 
conducted to mitigate any remaining risks. 
We recommend that you follow FDAs guidance Use of International Standard ISO 10993-1, 
'Biological evaluation of medical devices - Part 1: Evaluation and testing within a risk 
4 
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management process,'4 which identifies the types of biocompatibility assessments that should be 
considered and recommendations regarding how to conduct related tests. 
 
Per ISO 10993-1: Biological evaluation of medical devices  Part 1: Evaluation and testing 
within a risk management process and Attachment A of FDAs guidance on ISO-10993-1, 
biliary stents are implant devices in permanent contact with tissue/bone. Therefore, we 
recommend the following biocompatibility endpoints be addressed in your biocompatibility 
evaluation: 
  cytotoxicity; 
  sensitization; 
  irritation or intracutaneous reactivity; 
  acute systemic toxicity; 
  material-mediated pyrogenicity; 
  subacute/subchronic toxicity;  
  chronic toxicity; and 
  implantation. 
 
Per ISO 10993-1: Biological evaluation of medical devices  Part 1: Evaluation and testing 
within a risk management process and Attachment A of FDAs guidance on ISO-10993-1, 
SDSes are considered to have limited duration contact with mucosal membrane (endoscopic 
delivery) or breached tissue (percutaneous transhepatic delivery). Therefore, we recommend the 
following biocompatibility endpoints be addressed in your biocompatibility evaluation: 
  cytotoxicity; 
  sensitization; 
  irritation or intracutaneous reactivity; 
  acute systemic toxicity (percutaneous transhepatic delivery only); and 
  material-mediated pyrogenicity (percutaneous transhepatic delivery only). 
 
The following additional consideration is recommended for biliary stents: 
  As it may affect the biocompatibility of the device, you should provide information on 
specific stent processing steps, including heat treatment and any subsequent surface 
finishing steps that may be employed. 
D.  Sterility 
Significance: A biliary stent and associated SDS should be adequately sterilized to minimize 
infections and related complications. 
                                                 
4 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/use-international-standard-iso-10993-
1-biological-evaluation-medical-devices-part-1-evaluation-and.  
 
5 
  Contains Nonbinding Recommendations 
Recommendation: For biliary stents and associated SDSes labeled as sterile, we recommend that 
you provide information for the final device in accordance with FDAs guidance Submission 
and Review of Sterility Information in Premarket Notification (510(k)) Submissions for Devices 
Labeled as Sterile.5 
E.  Shelf Life and Packaging 
Significance: Shelf-life testing is conducted to support the proposed expiration date through 
evaluation of the package integrity for maintaining device sterility and/or evaluation of any 
changes to device performance or functionality. 
Recommendation: With respect to package integrity for maintaining device sterility, you should 
provide a description of the packaging, including how it will maintain the devices sterility, and a 
description of the package integrity test methods, but not the package test data. We recommend 
that package integrity test methods include simulated distribution and associated package 
integrity, as well as simulated (and/or real-time) aging and associated seal strength testing, to 
validate package integrity and shelf life claims. We recommend you follow the methods 
described in the FDA-recognized series of consensus standards AAMI/ANSI/ISO 11607-1: 
Packaging for terminally sterilized medical devices  Part 1: Requirements for materials, sterile 
barrier systems and packaging and AAMI/ANSI/ISO 11607-2: Packaging for terminally 
sterilized medical devices  Part 2: Validation requirements for forming, sealing and assembly 
processes. 
With respect to evaluating the effects of aging on device performance or functionality, shelf-life 
studies should evaluate critical device properties to ensure that it will perform adequately and 
consistently during the entire proposed shelf life. To evaluate device functionality, we 
recommend that you assess each of the bench tests described in Section V.G below and repeat 
all tests that evaluate design components or characteristics that are potentially affected by aging. 
We recommend that you provide a summary of the test methods used for your shelf life testing, 
results and the conclusions drawn from your results. If you use devices subject to accelerated 
aging for shelf life testing, we recommend that you specify the way in which the devices were 
aged. We recommend that you age your devices as per the currently FDA recognized version of 
ASTM F1980: Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical 
Devices and specify the environmental parameters established to attain the expiration date. For 
devices or components containing polymeric materials, you should plan to conduct testing on 
real-time aged samples to confirm that the accelerated aging is reflective of real-time aging. This 
testing should be conducted in parallel with 510(k) review and clearance with results 
documented to file in the design history file (i.e., complete test reports do not need to be 
submitted to FDA). 
                                                 
5 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/submission-and-review-sterility-
information-premarket-notification-510k-submissions-devices-labeled.  
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  Contains Nonbinding Recommendations 
F.  Magnetic Resonance (MR) Compatibility for Passive 
Implants 
Significance: MR imaging of patients with biliary stents poses the following potential hazards: 
  movement of the stent, resulting in tissue damage or displacement of the stent; 
  heating of the tissue surrounding the stent, resulting in damage to the biliary duct and 
surrounding tissue; and 
  image artifacts near the stent that may render MR images of nearby anatomy 
uninterpretable or misleading. 
 
Recommendation: We recommend that you address the issues affecting the safety and 
compatibility of your biliary stent in the MR environment as described in the FDA guidance 
Establishing Safety and Compatibility of Passive Implants in the MR (Magnetic Resonance) 
Environment.6  
If you would like to market stents of various sizes and shapes, then we recommend you follow 
our recommendations in the FDA guidance, Assessment of Radiofrequency-Induced Heating in 
the Magnetic Resonance (MR) Environment for Multi-Configuration Passive Medical Devices.7 
G.  Non-Clinical Bench Testing 
Some of the performance tests described in this section should be performed for all biliary stents 
and SDSes, whereas others should only be performed for those with specific designs (e.g., 
balloon expandable stents). This information is provided for each test described in this section. 
We believe that each test supports the determination of substantial equivalence of biliary stents. 
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 a scientific justification 
describing why the test is not applicable. 
We recommend you compare the results of these performance tests for your device to those 
obtained for the predicate or an appropriate reference device (refer to Appendix A). For 
information on the recommended content and format of test reports for the testing described in 
this section, refer to FDAs guidance, Recommended Content and Format of Non-Clinical 
Bench Performance Testing Information in Premarket Submissions.8 
 
The following tests are recommended for biliary stents: 
                                                 
6 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/establishing-safety-and-
compatibility-passive-implants-magnetic-resonance-mr-environment.  
7 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/assessment-radiofrequency-induced-
heating-magnetic-resonance-mr-environment-multi-configuration.  
8
 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/recommended-content-and-format-
non-clinical-bench-performance-testing-information-premarket. 
7 
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(1)  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. 
a.  Pitting Corrosion Potential 
We recommend that you characterize the corrosion potential of your as-manufactured stent 
according to the method described in the currently recognized version of ASTM F2129: 
Standard test method for conducting cyclic potentiodynamic polarization measurements to 
determine the corrosion susceptibility of small implant devices (or an equivalent method with 
justification). The test setup should meet the criteria outlined in the current version of ASTM G5: 
Standard reference test method for making potentiodynamic anodic polarization measurements. 
Testing should be performed after subjecting the device to simulated use testing, which includes 
crimping, tracking, and deployment of the device through an in vitro fixture that mimics in vivo 
anatomic conditions. Alternatively, the stent may be subjected to strains expected during 
simulated use (e.g., bending) without passing through a tracking fixture, with justification. This 
device conditioning is intended to simulate the clinical conditions of the stent at the time of 
implantation. Simulated bile should be used as the standard test solution. 
Test reports for pitting corrosion potential testing should be consistent with the currently 
recognized version of ASTM F2129. For example, test reports should include corrosion/rest 
potentials, breakdown potentials, description of observed corrosion with photographic 
documentation, as well as polarization curves. When practical, we recommend that you plot all 
polarization curves in one graph. You should report whether your test setup met the criteria 
outlined in the current version of ASTM G5. Results should be assessed against your acceptance 
criteria. The acceptance criteria for the pitting corrosion testing should be determined by 
comparison to a legally marketed predicate device. Alternatively, while there is a lack of data 
directly linking in vitro corrosion testing to in vivo corrosion outcomes, conservative guidelines 
have been published by Rosenbloom and Corbett, which may also be used to establish 
acceptance criteria.9 
Literature or previous performance data may support the pitting susceptibility assessment of your 
stent. However, the materials, design, and fabrication processes specific to your stent may reduce 
or eliminate the applicability of literature or previous experience with your device. For example, 
the pitting corrosion resistance of nitinol is sensitive to processing variables such as heat 
treatment and surface finish, and therefore literature would not be applicable. In cases where 
manufacturing changes that could impact surface finish are implemented, the currently 
                                                 
9
 Rosenbloom, S. N. and R. A. Corbett (2006). An Assessment of ASTM F 2129 Test Results Comparing Nitinol to 
Other Implant Alloys. Proceedings of the International Conference on Shape Memory and Superelastic 
Technologies (ASM International), Pacific Grove, CA. 
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  Contains Nonbinding Recommendations 
recognized version of ASTM F2129 testing or surface characterization should be performed to 
demonstrate that the surface is not adversely altered. 
b.  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 F3044: Standard test method for evaluating the 
potential for galvanic corrosion for medical implants or their equivalents. 
As an alternative to using marketed stents for galvanic corrosion testing, coupons representing an 
expected worst-case galvanic coupling, that are subjected to identical manufacturing processes 
may be used. In addition, a justification may be provided, in lieu of testing, if the expected 
worst-case galvanic coupling potentials are small and if the relative surface ratios of the cathodic 
to anodic materials are low (e.g., marker band to stent surface ratio). 
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. 
(2)  Stent Dimensional and Functional Attributes 
a.  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.  
Un-expanded Stents 
If your stent is not contained within a delivery system, you should provide dimensional 
measurements and tolerances for un-expanded stents on the deployment catheter. The results 
should support the dimensions in the device description. 
Balloon Expandable Stents 
You should measure and report the expanded diameter of balloon expandable stents. You may do 
this when creating a compliance chart (see Section V.G(3)d for recommended methods for 
creating a compliance chart). 
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Self-Expanding Stents 
You should verify the unconstrained expanded diameter of self-expanding stents with 
measurement data. 
b.  Foreshortening 
Significance: Foreshortening, i.e., dimensional changes to the stent that may occur during 
deployment, influences final stent length. Knowledge of the foreshortening characteristics aids in 
proper stent length selection and proper placement in the body. Foreshortening is a measurement 
of the difference in length between the un-expanded and expanded stent. 
Recommendation: FDA recommends that you report the decrease in length of the stent between 
the catheter-loaded condition (un-expanded stent) and the deployed condition (fully expanded 
stent) for every length and diameter combination.  
We recommend that you report the results in terms of a percentage of the loaded (undeployed) 
length as shown below: 
Undeployed Length-Fully Expanded Length
Percent Foreshortening=100  
Undeployed Length
( )
 
See Section V.I below for recommendations on data presentation of the percent foreshortening 
of self-expanding stents in your labeling. 
c.  Recoil for Balloon Expandable Stents 
Significance: The recoil behavior of balloon expandable stents influences proper device 
selection, sizing, and acute post-implant results. 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 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 the currently recognized version of ASTM F2079: 
Standard test method for measuring intrinsic elastic recoil of balloon-expandable stents or their 
equivalents. 
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d.  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.  
Recommendation: We recommend that you examine your deployed stent and report any 
evidence of stent defects that could negatively impact the performance of the stent such as, but 
not limited to, the following: 
  cracks; 
  scratches;  
  permanent set (an irreversible deformation); and 
  fretting. 
 
If you expect that your stents will be overlapped during clinical procedures and the design allows 
for micromotion between components, such as woven wires, that may disrupt an associated 
coating or passive film after implantation, then we recommend that you address the possibility of 
fretting as part of the stent integrity testing. If applicable, overlapped stents should be subjected 
to physiologically relevant clinical use conditions. 
Examination should be performed after subjecting the device to simulated use testing, which 
includes crimping, tracking, and deployment of the device through an in vitro fixture that mimics 
in vivo anatomic conditions. Alternatively, the stent may be subjected to strains expected during 
simulated use (e.g., bending) without passing through a tracking fixture, with justification. This 
device conditioning is intended to simulate the clinical conditions of the stent.  
We recommend that you use either 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 damage, we recommend that you examine or inspect the following: 
  for balloon expandable stents, after expansion to the largest diameter listed in your 
labeling; and 
  for self-expanding stents, after expansion to the unconstrained diameter. 
 
e.  Radial Compression Force 
Significance: Radial compression force characterizes the ability of the stent to resist collapse 
under external loads. 
Recommendation: We recommend that you report a value for the force required to compress the 
stent once it is expanded. 
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FDA recommends that you measure and report values for each labeled stent diameter. FDA 
recommends that you evaluate different stent lengths if the compression force could vary as a 
function of the total stent length. 
f.  Radial Outward Force 
Significance: Radial outward force is the force applied to tissues surrounding a self-expanding 
stent after deployment. Excessive radial outward force could injure the surrounding bile duct 
tissue, while a radial outward force that is too low can result in incomplete apposition of the stent 
to the tumor or lumen. 
Recommendation: We recommend that you measure the radial outward force exerted by self-
expanding stents against the contacting tissue after deployment. FDA recommends that you 
measure and report values for each labeled stent diameter. If a particular stent size or model is 
indicated for use in a range of lumen sizes, your assessment should cover the range of possible 
lumen sizes, or should include a rationale for not assessing the entire indicated range. We 
recommend that you evaluate different stent lengths if the radial force could vary as a function of 
the total stent length.  In addition, if you expect that the radial outward force of your stent is not 
axially uniform (e.g., if your stent has a tapered length or flared portions), we recommend that 
you measure the radial force at multiple locations along the length of the stent. 
g.  Radiopacity 
Significance: Stent visibility using fluoroscopic or radiographic imaging aids in proper stent 
placement and allows follow-up and secondary treatment. 
Recommendation: FDA recommends that you evaluate the radiopacity of your stent(s) using the 
stent size that has the least radiopaque configuration (e.g., smallest diameter and the shortest 
length), supported with a scientific justification during the following stages in the life of the 
stent: 
  delivery; 
  deployment, if separate from delivery; and 
  post-implantation. 
 
We recommend that you provide a qualitative or quantitative assessment of the visibility of the 
stent on real-time and plain film x-ray or electronic image formats. It is acceptable to use data 
from images of animal implants, in vitro phantoms, or equivalent models. 
(3)  Stent Delivery System (SDS) Dimensional and Functional 
Attributes 
Unless otherwise noted, we recommend that you conduct all testing on complete sterilized 
assemblies with stents. We also recommend that you thermally equilibrate all test samples in a 
37 C saline bath or another media that is representative of the clinical environment with a 
justification. 
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a.  Delivery, Deployment, and Withdrawal 
Significance: The SDS should safely and reliably deliver the biliary stent to the intended location 
according to the instructions for use, without damage to the stent or injury to the patient. This 
testing is used to validate the accuracy and repeatability of the delivery system. 
Recommendation: FDA recommends that you test that the SDS can safely and reliably deliver 
the stent to the intended location. We also recommend that you demonstrate that the stent is not 
adversely affected by the SDS, both during deployment and withdrawal in a relevant test model. 
The test model you choose should mimic actual clinical simulation parameters of the biliary 
anatomy including the following attributes: 
  lubricity; 
  tortuosity; 
  stricture size; and 
  length of delivery system outside the body (model). 
 
SDS performance testing should include, but may not be limited to the following: 
  delivery force; 
  deployment force; 
  withdrawal force; and 
  deployment accuracy. 
 
b.  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 an 
adverse clinical outcome. 
Recommendation: We recommend that you test balloons with mounted stents that are not 
constrained by any test fixture, such as tubing. We recommend that you conduct testing on the 
longest length of every stent diameter, plus the smallest diameter at the shortest length and the 
largest diameter at the shortest length. Table 2 illustrates the recommended test matrix for a stent 
design that ranges in diameter from 8.0 to 14.0 mm and ranges in length from 40 to 80 mm. 
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Table 2: Recommended Test Matrix for RBP
 
Stent  Stent Length 
Diameter  (mm) 
(mm)  40  50  60  80 
8.0  X      X 
10.0        X 
12.0        X 
14.0  X      X 
We recommend that you test according to the example in Table 2 for each balloon size with a 
different labeled RBP. We recommend that you increase balloon pressure in uniform increments 
until failure. 
We recommend that you record as test failures any loss of the following: 
  integrity of the balloon, such as a rupture or leak; and 
  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. 
c.  Balloon Fatigue (Balloon Expandable Stents Only) 
Significance: Balloons on SDSes are often inflated multiple times during clinical use. Failure of 
the balloon to withstand multiple inflations could lead to adverse clinical consequences. 
Recommendation: FDA recommends that you determine the repeatability, to ten inflations, of 
successful balloon inflation to the RBP. If you propose to market stents of various sizes, then we 
recommend you sample and test stents using the four corners paradigm as shown in Table 3:  
  smallest diameter, shortest length; 
  smallest diameter, longest length; 
  largest diameter, shortest length; and 
  largest diameter, longest length. 
   
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Table 3: Four Corners Test Paradigm Example 
Stent  Stent Length 
Diameter  (mm) 
(mm)  40  50  60  80 
8.0  X      X 
10.0         
12.0         
14.0  X      X 
 
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 ten 
cycles. 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. 
d.  Stent Diameter vs. Balloon Pressure (Compliance Chart: 
Balloon Expandable Stents Only) 
Significance: The diameter of a deployed balloon expandable stent varies with the applied 
balloon pressure. A compliance chart in the labeling that relates stent diameter to balloon 
pressure guides selection of stent size to fit the target stricture. 
Recommendation: FDA recommends that you test all stent diameters at their longest lengths. 
Table 4 illustrates the recommended test matrix for a stent design that ranges in diameter from 
8.0 to 14.0 mm and ranges in length from 40 to 80 mm. 
Table 4: Recommended Test Matrix for Compliance Chart 
Stent  Stent Length 
Diameter  (mm) 
(mm)  40  50  60  80 
8.0        X 
10.0        X 
12.0        X 
14.0        X 
We recommend that you identify the nominal inflation pressure and RBP, as shown in the 
example below. We recommend that you test multiple product lots. We also recommend that you 
clearly document any data rounding. Table 5 shows a sample compliance chart for a stent with 8 
mm, 10 mm, and 12 mm diameters, with a RBP of 14.0 atmospheres (atm). The nominal 
diameter occurs at 12.0 atm. 
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  Contains Nonbinding Recommendations 
Table 5: Sample Compliance Chart for a Balloon Expandable Stent 
Stent Nominal Diameter  
Pressure  where x = stent inner diameter at the given pressure 
(atm)  8.0 mm Stent Inner  10.0 mm Stent Inner  12.0 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  8.0  10.0  12.0 
13.0  X  x  x 
14.0*  X  x  x 
*RBP 
e.  SDS Bond Strength 
Significance: Failure of bonds in the SDS could lead to device failure and clinical complications. 
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 SDS. We 
recommend that you precondition (e.g., track the device through simulated anatomy) the device 
prior to conducting this testing to ensure that SDS bond strength is maintained after tracking. 
f.  Crossing Profile 
Significance: Changes in the cross-sectional shape and size of the SDS along its length affect the 
SDSs ability to cross strictures. 
Recommendation: FDA recommends that you measure and report the crossing profile of your 
SDS, defined as the maximum distance between 2 points on the perimeter of a cross-section 
through the SDS. The crossing profile should be reported for the portion of the SDS between the 
proximal end of the mounted or pre-loaded stent and the distal tip of the SDS. Testing should 
address potential differences in crossing profile that may exist in the circumferential direction 
(i.e., the cross-sectional shape may not be a circle). To address this issue, 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). 
g.  Balloon Inflation and Deflation Time (Balloon Expandable 
Stents Only) 
Significance: Balloons occlude the target lumen and obstruct the flow of bile while inflated. 
Inflation and deflation times affect obstruction time. Inflation of a balloon for extended periods 
of time could lead to adverse clinical consequences.  
Recommendation: FDA recommends that you specify the balloons inflation and deflation times 
and demonstrate that the balloon inflates and deflates within those times. We recommend that 
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you describe any observed difficulties with balloon deflation or SDS extraction after deploying 
the stent. 
h.  Stent Securement for Unsheathed Stents 
Significance: Dislodgment of the stent prior to deployment can result in perforation or other 
trauma in the target lumen. Stents without sheaths may dislodge if they catch on tortuous 
anatomy, guide catheters, or other devices. 
Recommendation: FDA recommends that you evaluate the force that will dislodge the stent from 
the SDS under clinically relevant conditions. We recommend that the test include insertion 
through a tortuous path that simulates the anatomy of commonly stented areas of the biliary tract 
to and including the stricture site. We recommend that the tortuous path be sized appropriately 
for the stent size being tested. We recommend that you submit a photograph, diagram, or 
description of the tortuous path, including dimensions. 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. 
FDA recommends that you address the modes of dislodgement as described below: 
Dislodgement by Forward Motion 
Advancing a stent delivery system across a tight tumor could result in stent dislodgement. We 
recommend testing the stent by passing it across a simulated tight tumor in the tortuous path. 
Dislodgement by Reverse Motion 
Withdrawing a SDS through another device, such as an endoscope or guiding catheter, 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 recommended in the 
instructions for use. 
H.  Clinical Performance Testing 
Significance: In some cases, pre-clinical evaluation does not fully characterize all clinical 
experience, outcomes, and risks. In such cases, we recommend that you conduct in vivo (i.e., 
clinical) studies to evaluate device safety and effectiveness for new and modified biliary stents 
and SDSes. 
Recommendation: Clinical evidence is generally unnecessary for biliary stents; however, such 
testing may be requested in situations such as the following:  
  polymer covered designs; 
  indications for use dissimilar from legally marketed devices of the same type that would 
not constitute a new intended use; 
  designs or sizes dissimilar from designs previously cleared under a premarket 
notification; 
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  Contains Nonbinding Recommendations 
  different technology from that used in legally marketed devices of the same type, yet 
does not raise different question of safety or effectiveness; and 
  stents that are intended to be removable. 
 
We will consider alternatives to clinical testing when the proposed alternatives are supported by 
an adequate scientific rationale. If a clinical study is needed to demonstrate substantial 
equivalence (i.e., conducted prior to obtaining 510(k) clearance of the device), the study should 
generally be conducted under the Investigational Device Exemptions (IDE) regulation, 21 CFR 
812. Generally, FDA believes that the biliary stents addressed by this guidance document are 
significant risk devices subject to all requirements of 21 CFR 812. See the FDA Guidance titled, 
Significant Risk and Nonsignificant Risk Medical Device Studies.10 In addition to the 
requirements of 21 CFR 812, sponsors of such trials of a device conducted in the United States 
(US) must comply with the regulations governing institutional review boards (21 CFR 56) and 
informed consent (21 CFR 50). 
When data from clinical investigations conducted outside the US are submitted to FDA for these 
devices, the requirements of 21 CFR 812.28 may apply.11 21 CFR 812.28 outlines the conditions 
for FDA acceptance of clinical data from investigations conducted outside the US when 
submitted to support premarket submissions. For more information, see the FDA guidance 
Acceptance of Clinical Data to Support Medical Device Applications and Submissions: 
Frequently Asked Questions.12 
 
I.  Labeling  
The premarket notification must include proposed labeling in sufficient detail to satisfy the 
requirements of 21 CFR 807.87(e). Proposed labels and labeling, sufficient to describe the biliary 
stent and SDS, their intended use, and the directions for use must be provided. 
As prescription devices, biliary stent systems are exempt from having adequate directions for lay 
use required under section 502(f)(1) of the FD&C Act (21 U.S.C.  352(f)(1))) as long as the 
conditions in 21 CFR 801.109 are met. For instance, labeling must include adequate information 
for the intended user of the device, including indications, effects, routes, methods, frequency and 
duration of administration and any relevant hazards, contraindications, side effects, and 
precautions (21 CFR 801.109(d)).  
The labeling for biliary stent systems should include the following information. 
                                                 
10 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/significant-risk-and-nonsignificant-
risk-medical-device-studies.  
11 This applies to data from clinical investigations that began on or after February 21, 2019 and are submitted to 
support a premarket submission, including IDEs, premarket approval applications (PMAs), and 510(k)s. 
12 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/acceptance-clinical-data-support-
medical-device-applications-and-submissions-frequently-asked.  
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(1)  Display of Common Name and Trade Name 
As discussed in Section II, FDA has placed limitations on most biliary stent substantial 
equivalence determinations pursuant to section 513(i)(1)(E) of the FD&C Act. Under these 
limitations, FDA has required a statement in labeling that provides appropriate information 
regarding an intended use of the device not identified in the proposed labeling. Specifically, FDA 
has required the prominent display of biliary in close proximity to the trade name and 
everywhere that the trade name appears in the labeling, such as all layers of packaging (e.g., 
pouches, boxes, carton labels), the instructions for use, and other such materials. We recommend 
that the word biliary or biliary stent should be at least three-fourths the size of your trade 
name and using the same font style as the trade name (e.g., both displayed in Times New Roman, 
bold type). If the identical device for which clearance is being sought has also been approved for 
a vascular indication through a separate marketing application, this limitation may not apply. 
(2)  Device Description 
We recommend that your device description include the following information: 
  photographs and/or drawings that illustrate design, function, and compatibility of stent, 
delivery system, and all accessories; 
  statement of whether the stent is balloon-expandable or self-expanding; 
  list of all stent materials; 
  table that displays all stent diameters and lengths (when more than one model); 
  description of any ancillary or accessory devices that are packaged with your stent system 
when no separate labeling is available; 
  compatibility with guiding catheter sizes; 
  balloon rated burst pressure (balloon expandable stents only); and 
  specification for SDS crossing profile. 
 
(3)  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. 
(4)  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. For example, if your performance testing does not address having your stents 
overlap within the bile duct, and you intend for stents to potentially be overlapped, then we 
recommend you include the following warning: The safety and effectiveness of overlapping 
stenting devices within the biliary tree has not been established. 
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  Contains Nonbinding Recommendations 
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 and 
use of the device is associated with a serious risk or hazard. As discussed in Section II, FDA has 
placed limitations on most substantial equivalence determinations for biliary stents pursuant to 
section 513(i)(1)(E) of the FD&C Act. Under these limitations, FDA has required the following 
statement in the Warnings section of biliary stent device labels: 
The safety and effectiveness of this device for use in the vascular system has not been 
established. 
As described in FDAs guidance, Deciding When to Submit a 510(k) for a Change to an 
Existing Device,13 manufacturers are permitted to make certain labeling changes without 
submission of a new 510(k). The labeling limitations included in the "SE letter with 
Limitations," however, are required by section 513(i)(1)(E) of the FD&C Act. Therefore, a new 
510(k) must be submitted before these limitations are modified in any way or removed from the 
device's labeling. Additional information regarding SE with limitations can be found in FDAs 
guidance, Determination of Intended Use for 510(k) Devices; Guidance for CDRH Staff 
(Update to K98-1).14 If the identical device for which clearance is being sought has also been 
approved for a vascular indication through a separate marketing application, this limitation may 
not apply. 
(5)  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, the following: 
  lack of long-term safety and effectiveness data; 
  lack of safety and effectiveness data for special patient populations; 
  need for appropriate physician training; and 
  anatomical or physiological limitations on the effectiveness of the device. 
 
Stent handling, stent placement, stent system removal, and any post-implant precautions are also 
appropriate for inclusion in this section. 
(6)  MRI Safety Information 
We recommend you follow the labeling guidance in Establishing Safety and Compatibility of 
Passive Implants in the Magnetic Resonance (MR) Environment.15 We also recommend that 
you use the standardized terminology and icons specified in ASTM F2503: Standard Practice 
                                                 
13 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/deciding-when-submit-510k-
change-existing-device.  
14 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/determination-intended-use-510k-
devices-guidance-cdrh-staff-update-k98-1.  
15 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/establishing-safety-and-
compatibility-passive-implants-magnetic-resonance-mr-environment. 
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  Contains Nonbinding Recommendations 
for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance 
Environment. 
(7)  Overview of Clinical Studies 
As we explained in Section V.H, clinical studies are not necessary to support many biliary stent 
applications. However, if clinical data is included in the submission, you should provide a 
narrative description of the study or studies relevant to the stent. The narrative should be brief, 
and for each study, it should include the following: 
  description of the design of the study, including any randomization, blinding, and the 
control or controls used; 
  statement of the number of patients enrolled; 
  statement of the number of investigational sites both inside the US and outside the United 
States (OUS); 
  description of the primary study endpoint or endpoints; 
  description of the results of the study (e.g., adverse events, endpoint data, statistical 
analysis); and 
  statement of the amount of available follow-up. 
(8)  Potential Adverse Events 
You should include potential adverse events associated with stenting of the biliary duct, and if 
applicable, with endoscopic procedures. 
(9)  Directions for Use 
You should include directions for proper preparation and use of the device. If multiple SDSes are 
available, you should clearly indicate differences specific to each SDS. An example would be to 
indicate the difference between an endoscopic and a percutaneous delivery system and to provide 
specific directions for each one. 
Compliance Chart (Balloon Expandable Stents Only) 
You should include a graphical and/or tabular presentation of inflation pressure vs. stent inner 
diameter (ID), i.e., a compliance chart, over the full range of recommended deployed stent 
diameters derived from bench testing. If you round the data, you should footnote the chart to 
indicate that the data is rounded. We recommend the format presented in Table 5. 
Percent Foreshortening (Self-Expanding Stents Only) 
You should provide a table that includes the following: 
  stent length; 
  stent diameter; 
  stent length in undeployed condition; and 
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  stent percent foreshortening defined as: 
 
Undeployed Length-Fully Expanded Length
100  
Undeployed Length
( )
 
(10)  Patient Labeling 
You should provide examples of all patient labeling, including the patient guide and implant 
card, that you intend to provide to patients. When preparing patient labeling, we recommend you 
use the FDA guidance, Guidance on Medical Device Patient Labeling.16 
For MR Conditional stents, we recommend you include all conditions for safe MR use as 
specified in Establishing Safety and Compatibility of Passive Implants in the Magnetic 
Resonance (MR) Environment,17 as well as the MR Conditional icon from the currently 
recognized version of ASTM F2503. 
                                                 
16 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-medical-device-patient-
labeling.  
17 https://www.fda.gov/regulatory-information/search-fda-guidance-documents/establishing-safety-and-
compatibility-passive-implants-magnetic-resonance-mr-environment.  
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1  Appendix A: Example Test Summary Table 
2  See below for an example of how test summary information may be organized. 
3   
Test  Sizes Tested  Test Method or  Accept/Reject  Results 
and Sample  Standard  Criteria 
Sizes  Reference 
Material  *Material Composition         
Characterization 
*Corrosion Resistance         
Stent  *Dimensional Verification         
Dimensional and 
*Foreshortening         
Functional 
Attributes  *Recoil for Balloon Expandable Stents         
Stent Integrity         
*Radial Compression Force         
*Radial Outward Force         
MR Safety and Compatibility:         
a.  Magnetically Induced 
Deflection Force 
b.  Magnetically Induced Torque 
c.  RF induced Heating 
d.  Image Artifact 
Radiopacity         
Delivery System  *Delivery, Deployment, and Withdrawal         
Dimensional and 
Balloon Rated Burst Pressure (balloon         
expandable stents only) 
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Test  Sizes Tested  Test Method or  Accept/Reject  Results 
and Sample  Standard  Criteria 
Sizes  Reference 
Functional  Balloon Fatigue (balloon expandable stents         
Attributes  only) 
Stent Diameter vs. Balloon Pressure         
(Compliance Chart) (balloon expandable 
stents only) 
*Catheter Bond Strength         
Crossing Profile         
*Balloon Inflation and Deflation Time         
(balloon expandable stents only) 
*Stent Securement for Unsheathed Stents         
Biocompatibility  Biocompatibility         
4  *Items should have results compared to those of the predicate or a suitable reference device. 
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