EN ISO 25539-2:2008

SLOVENSKI STANDARD
01-november-2008
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SIST EN 14299:2004
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Cardiovascular implants - Endovascular devices - Part 2: Vascular stents (ISO 25539-
2:2008)
Kardiovaskuläre Implantate - Endovaskuläre Implantate - Teil 2: Gefäßstents (ISO 25539
-2:2008)
Implants cardiovasculaires - Dispositifs endovasculaires - Partie 2: Endoprothèses
vasculaires (ISO 25539-2:2008)
Ta slovenski standard je istoveten z: EN ISO 25539-2:2008
ICS:
11.040.40 Implantanti za kirurgijo, Implants for surgery,
protetiko in ortetiko prosthetics and orthotics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 25539-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2008
ICS 11.040.40 Supersedes EN 14299:2004
English Version
Cardiovascular implants - Endovascular devices - Part 2:
Vascular stents (ISO 25539-2:2008)
Implants cardiovasculaires - Dispositifs endovasculaires - Kardiovaskuläre Implantate - Endovaskuläre Implantate -
Partie 2: Endoprothèses vasculaires (ISO 25539-2:2008) Teil 2: Gefäßstents (ISO 25539-2:2008)
This European Standard was approved by CEN on 30 August 2008.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 25539-2:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 93/42/EEC.4

Foreword
This document (EN ISO 25539-2:2008) has been prepared by Technical Committee ISO/TC 150 "Implants for
surgery" in collaboration with Technical Committee CEN/TC 285 “Non-active surgical implants” the secretariat
of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by March 2009, and conflicting national standards shall be withdrawn at
the latest by March 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 14299:2004.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EC Directive(s).
For relationship with EC Directive(s), see informative Annex ZA, which is an integral part of this document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 25539-2:2008 has been approved by CEN as a EN ISO 25539-2:2008 without any
modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential Requirements of
EU Directive 93/42/EEC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 93/42/EEC
Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the clauses of this
standard given in table ZA confers, within the limits of the scope of this standard, a presumption of conformity
with the corresponding Essential Requirements of that Directive and associated EFTA regulations.
Table ZA — Correspondence between this European Standard and Directive 93/42/EEC
Clause(s)/sub-clause(s) Essential Requirements (ERs) of Directive Qualifying
of this International 93/42/EEC remarks/Notes
Standard
4 1, 2, 4, 7.1
5 1, 2, 3, 4, 5, 7.1, 7.2, 7.3, 7.5, 8, 9.2

6 1, 2, 7.1, 7.2, 7.3, 7.5, 8.2, 9.2

7 1, 2, 3, 4, 6, 7.1, 7.2, 8, 9.2, 14

8 1, 2, 3, 5, 7.1, 7.2
9 1, 2, 3, 7.2, 8.1, 8.3, 8.4
10 1, 2, 3, 5, 7.2, 8.3, 8.4
11 1, 2, 8.7, 13.1, 13.3, 13.4, 13.6

WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within
the scope of this standard.
INTERNATIONAL ISO
STANDARD 25539-2
First edition
2008-09-01
Cardiovascular implants — Endovascular
devices —
Part 2:
Vascular stents
Implants cardiovasculaires — Dispositifs endovasculaires —
Partie 2: Endoprothèses vasculaires

Reference number
ISO 25539-2:2008(E)
©
ISO 2008
ISO 25539-2:2008(E)
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ii © ISO 2008 – All rights reserved

ISO 25539-2:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 General requirements. 4
4.1 Classification. 4
4.2 Size. 5
4.3 Intended clinical use designation . 5
5 Intended performance . 5
6 Design attributes. 5
6.1 General. 5
6.2 Delivery system and stent system . 6
6.3 Implant . 6
7 Materials . 7
8 Design evaluation . 8
8.1 General. 8
8.2 Sampling. 8
8.3 Conditioning of test samples . 9
8.4 Reporting . 9
8.5 Delivery system and stent system . 10
8.6 Stent . 15
8.7 Preclinical in vivo evaluation. 24
8.8 Clinical evaluation . 28
9 Post market surveillance . 31
10 Manufacturing . 32
11 Sterilization. 32
11.1 Products supplied sterile. 32
11.2 Products supplied non-sterile . 32
11.3 Sterilization residuals. 32
12 Packaging . 32
12.1 Protection from damage in storage and transport. 32
12.2 Marking . 33
12.3 Information supplied by the manufacturer . 34
Annex A (informative) Attributes of endovascular devices — Vascular stents — Technical and
clinical considerations . 36
Annex B (informative) Bench and analytical tests. 42
Annex C (informative) Definitions of reportable clinical events. 45
Annex D (informative) Test methods. 48
Annex E (informative) Supplement to fatigue durability test analytical approach. 86
Bibliography . 89

ISO 25539-2:2008(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 25539-2 was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee SC 2,
Cardiovascular implants and extracorporeal systems.
ISO 25539 consists of the following parts, under the general title Cardiovascular implants — Endovascular
devices:
⎯ Part 1: Endovascular prostheses
⎯ Part 2: Vascular stents
iv © ISO 2008 – All rights reserved

ISO 25539-2:2008(E)
Introduction
This part of ISO 25539 has been prepared in order to provide minimum requirements for endovascular
devices and the methods of test that will enable their evaluation. It is the second part of a proposed three-part
standard. ISO 25539-1 addresses endovascular prostheses and ISO 25539-3 will address vena cava filters.
ISO/TS 15539, from which this part of ISO 25539 is derived, serves as a rationale for the requirements of this
document. The Technical Specification ISO/TS 15539 was developed by first identifying the design
requirements for these devices and listing the potential device and clinical failure modes. Tests were then
identified to address each of the failure modes. The requirements provided in this part of ISO 25539 are based
on that assessment.
INTERNATIONAL STANDARD ISO 25539-2:2008(E)

Cardiovascular implants — Endovascular devices —
Part 2:
Vascular stents
1 Scope
1.1 This part of ISO 25539 specifies requirements for vascular stents, based upon current medical
knowledge. With regard to safety, it gives requirements for intended performance, design attributes, materials,
design evaluation, manufacturing, sterilization, packaging and information supplied by the manufacturer. It
should be considered as a supplement to ISO 14630, which specifies general requirements for the
performance of non-active surgical implants.
NOTE Due to the variations in the design of implants covered by this part of ISO 25539 and in some cases due to the
relatively recent development of some of these implants (e.g. bioabsorbable stents, polymeric stents), acceptable
standardized in vitro tests and clinical results are not always available. As further scientific and clinical data become
available, appropriate revision of this document will be necessary.
1.2 The scope of this part of ISO 25539 includes vascular stents used to treat vascular lesions or stenoses,
or other vascular abnormalities. These devices might or might not incorporate surface modifications of the
stent such as drug and/or other coatings. Stents covered with materials that significantly modify the
permeability of the uncovered stent are within the scope of ISO 25539-1. The stent design might dictate the
need to address functional requirements identified in both ISO 25539-1 and this part of ISO 25539.
1.3 Delivery systems are included in this part of ISO 25539 if they comprise an integral component of the
deployment of the vascular stent.
1.4 Procedures and devices used prior to the introduction of the vascular stent, such as balloon angioplasty
devices, are excluded from the scope of this part of ISO 25539.
1.5 Some pharmacological aspects of drug eluting stents are addressed in this part of ISO 25539, but this
document is not comprehensive with respect to the pharmacological evaluation of drug eluting stents.
1.6 Degradation and other time-dependent aspects of bioabsorbable and polymeric stents and coatings are
not addressed by this part of ISO 25539.
1.7 With the exception of sterilization, this part of ISO 25539 does not address requirements for the
evaluation of animal tissue products.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 10993 (all parts), Biological evaluation of medical devices
ISO 11135-1, Sterilization of health care products — Ethylene oxide — Part 1: Requirements for development,
validation and routine control of a sterilization process for medical devices
ISO 25539-2:2008(E)
ISO 11137-1, Sterilization of health care products — Radiation — Part 1: Requirements for development,
validation and routine control of a sterilization process for medical devices
ISO 11607 (both parts), Packaging for terminally sterilized medical devices
ISO 14155 (both parts), Clinical investigation of medical devices for human subjects
ISO 14160, Sterilization of single-use medical devices incorporating materials of animal origin — Validation
and routine control of sterilization by liquid chemical sterilants
ISO 14630, Non-active surgical implants — General requirements
ISO 14937, Sterilization of health care products — General requirements for characterization of a sterilizing
agent and the development, validation and routine control of a sterilization process
ISO 14971, Medical devices — Application of risk management to medical devices
ISO 17665-1, Sterilization of health care products — Moist heat — Part 1: Requirements for the development,
validation and routine control of a sterilization process for medical devices
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 14630 and the following apply.
NOTE Bench and analytical tests are described in Annex B. Reportable clinical events are defined in Annex C.
3.1
balloon-assisted deployment
use of a balloon to facilitate the complete deployment (or expansion) of a self-expanding stent
3.2
balloon winging
cross-sectional shape of the balloon when deflated which can cause problems during withdrawal
NOTE Examples include stent migration, damage to host vessel or balloon, and inability to remove the balloon.
3.3
delivery system
system or mechanism used to deliver the stent to the targeted position and to deploy the stent
NOTE The delivery system is removed after stent placement. Examples of delivery systems include balloon catheters
or mechanically activated systems.
3.4
determine
to quantitatively appraise or analyse
NOTE Also see evaluate (3.8).
3.5
dogboning
dumbbell-shaped balloon observed during stent deployment when the unconstrained ends of the balloon
expand beyond the dilated stent outer diameter
2 © ISO 2008 – All rights reserved

ISO 25539-2:2008(E)
3.6
coating
organic or inorganic material, other than living cells, intentionally applied by a manufacturer to a substrate
NOTE This coating can be intended to be permanent or temporary, and can be applied to the external and/or internal
surface.
3.7
drug content
amount of drug present on the surface(s) of a coating, as part of a coating or within the stent
3.8
evaluate
to qualitatively appraise or analyse
NOTE Also see determine (3.4).
3.9
lumen reduction
reduction of diameter or cross sectional area as observed by imaging
3.10
reportable clinical events
complications, failures or device-related observations, including all adverse events and adverse device effects,
that might be observed with clinical use of the stent system
NOTE Examples are listed in Annex C. These events might not have clinical significance and might not be
attributable to the device.
3.11
stent configuration
stent shape (e.g. cylindrical, tapered, flared, coiled, segmented, bifurcated)
3.12
stent outer surface area
contact area between the stent and the vessel
3.13
stent-free surface area
percentage of surface area of cylinder formed by the implant frame, which is not covered by implant material
3.14
stent system
vascular stent and its delivery system or a vascular stent mounted on the delivery balloon as specified in the
instructions for use (IFU)
3.15
vascular stent
stent
implant
transluminally placed balloon-expandable or self-expanding implant, which is used to treat vascular lesions by
providing a mechanical support after deployment to maintain or restore vessel integrity
NOTE 1 Stents can or cannot incorporate surface modifications of the stent such as drug and/or other coatings.
NOTE 2 The following stent types are within the Scope of this part of ISO 25539.
3.15.1
articulated stent
stent constructed of segments with distinct connections
ISO 25539-2:2008(E)
3.15.2
bare stent
stent without a coating or covering
NOTE Bare stents can be constructed of single or multiple materials.
3.15.3
bioabsorbable stent
stent that is designed to be a temporary structure without requiring explantation
3.15.4
balloon-expandable stent
stent where the diameter is increased from its pre-deployed size to its post-deployed size with the aid of a
balloon catheter
3.15.5
coated stent
stent with a surface layer of an additional material(s) that does not provide significant (e.g. more than 5 %)
structural support or appreciably reduce the permeability or stent-free surface area of the bare stent
3.15.6
composite stent
stent consisting of more than one material or material compound that provides significant (e.g. more than 5 %)
overall structural support upon deployment
3.15.7
covered stent
stent covered with an additional material(s) that appreciably reduces the permeability and/or eliminates the
stent-free surface area of the bare stent
NOTE Covered stents are within the Scope of ISO 25539-1. The stent design might dictate the need to address
functional requirements identified in both parts 1 and 2 of ISO 25539.
3.15.8
drug eluting stent
DES
stent that delivers a drug(s) over time
3.15.9
self-expanding stent
stent where the diameter increases from its pre-deployed size to its post-deployed size when released from
the delivery mechanism in absence of balloon inflation or other mechanical assistance
NOTE Self-expanding stents are within the scope of ISO 25539-1. The stent design might dictate the need to
address functional requirements identified in both parts 1 and 2 of ISO 25539.
4 General requirements
4.1 Classification
A stent shall be designated by its configuration (see 3.11), type (see 3.15), materials of construction, and any
surface modifications, coatings, and/or drugs.
4 © ISO 2008 – All rights reserved

ISO 25539-2:2008(E)
4.2 Size
The size of a stent shall be designated by the following characteristics:
a) external diameter;
1) self-expanding:
i) unconstrained external diameter of the device, expressed in millimetres;
ii) intended vessel lumen diameter range, expressed in millimetres;
2) balloon expandable: range of intended expanded internal diameters;
b) minimum and maximum usable length, expressed in millimetres or centimetres.
4.3 Intended clinical use designation
The intended clinical use shall be designated by one or more of the following:
a) abdominal aorta;
b) arterio-venous shunt for vascular access;
c) carotid;
d) coronary;
e) femoral;
f) iliac;
g) popliteal;
h) renal;
i) thoracic aorta;
j) thoraco-abdominal aorta;
k) tibial;
l) other arterial vessels to be specified;
m) other venous vessels to be specified.
5 Intended performance
The requirements for intended performance of ISO 14630 shall apply.
6 Design attributes
6.1 General
The requirements for design attributes of ISO 14630 apply. In addition, the following shall be taken into
account:
a) oxidation-potential, the possibility of crevice corrosion, passivation over the relevant parts;
b) fretting, galvanic and pitting corrosion;
ISO 25539-2:2008(E)
c) interface between implant and body:
1) fixation hooks if present;
2) relative movement between stent and tissue;
3) forces exerted by the stent on the surrounding tissue;
4) forces required to deform the stent if the deformation is permanent;
d) expected ingrowth, penetration, perforation, tilting and migration; introduction and delivery systems.
[15]
NOTE These additional items are adapted from Clause 5 of EN 12006-3:1998 .
The design attributes for vascular stents (with or without delivery system) are listed in Table A.2 with reference
to the test sections for the evaluation of the design (Clause 8). It is recognised that not all tests identified in a
category will be necessary or practical for any given stent and/or delivery system. The tests considered and
the rationale for selection and/or waiving of tests shall be recorded.
6.2 Delivery system and stent system
The design attributes to meet the intended performance of the delivery system shall additionally take into
account at least the following:
a) the ability of the system to permit consistent, accurate and safe access to the intended location;
b) the ability of the system to permit consistent, accurate and safe deployment of the stent;
c) the ability of the system to permit consistent and safe withdrawal of the delivery system;
d) the compliance of the system with the requirements of ISO 10993-1 and appropriate other parts of the
ISO 10993 series of International Standards (biocompatibility);
e) the ability of the system to minimise blood loss (haemostasis);
f) the visibility of the system under fluoroscopy or other technologies.
6.3 Implant
6.3.1 Stent
The design attributes to meet the intended performance of the stent shall additionally take into account at
least the following:
a) the ability of the stent to be consistently, accurately and safely deployed;
b) the ability of the stent to ensure effective fixation and apposition in the intended location within the
vasculature;
c) the ability of the stent to maintain adequate integrity;
d) the consistency of the stent dimensions and its design for compatibility for use in specified vessel
diameters;
e) the ability of the stent to maintain adequate blood flow through the lumen (patency);
f) the compatibility of the stent with exposure to magnetic resonance imaging (MRI) fields;
6 © ISO 2008 – All rights reserved

ISO 25539-2:2008(E)
g) the compliance of the stent with the requirements of ISO 10993-1 and appropriate other parts of the
ISO 10993 series of International Standards (biocompatibility);
h) the visibility of the stent under fluoroscopy or other technologies.
6.3.2 Coating
The design attributes to meet the intended performance of the coating shall additionally take into account at
least the following:
a) the ability of the coating to maintain adequate integrity over time according to design specifications
(e.g. freedom from significant delamination, flaps and bare spots);
b) the appropriate interaction between the coating and the stent (e.g. coating influenced corrosion of the
substrate);
c) the ability of the coating to maintain adequate resistance to unintended particulate generation;
d) the conformance of the coating dimensions and other coating parameters (e.g. porosity, density,
distribution) to the design requirements;
e) the effect of MRI on the coating of a coated stent (e.g. heating).
6.3.3 Drug
The design attributes to meet the intended performance of the stent if the coating is a drug or if a drug is
incorporated into the stent or coating shall additionally take into account at least the following:
a) the ability to reproducibly apply the desired drug type and amount to the stent;
b) the ability to release the desired amount of drug over the specified amount of time;
c) the conformance of the residual drug quantity to design specifications;
d) the freedom of the drug(s) from deleterious impurity and degradant levels at manufacture and with
storage;
e) the appropriate interaction between the drug and the coating and/or the stent to which the drug is applied;
f) the effect of MRI on the drug of a drug-eluting stent (e.g. heating).
7 Materials
The requirements for materials of ISO 14630 apply. Additional testing specific to certain materials (e.g. metals,
polymers, drugs) shall be performed to determine the appropriateness of the material for use in the design.
For example, Nitinol materials dependent on shape memory properties shall be subjected to testing in order to
assess transformation properties. In addition, for drug-eluting stents drug identity testing shall be performed,
including the identification of impurities and degradants. Electro-chemical potentials of differing metals (stents,
guidewires, other accessory devices) might require additional types of testing.
ISO 25539-2:2008(E)
8 Design evaluation
8.1 General
The requirements for design evaluation of ISO 14630 apply. A risk assessment shall be carried out and the
requirements of ISO 14971 shall apply.
Justification shall be provided for the properties not measured.
NOTE 1 All testing might not be appropriate for all stent system designs.
It is impossible to take into consideration all future and emerging technologies. The stent systems based on
these new technologies will need to be evaluated following the basic requirements of this part of ISO 25539.
Testing beyond the scope of this part of ISO 25539 might also be necessary in order to characterize these
stent systems. Consideration shall be given to the failure modes of the stent systems and their effects on the
performance of the implant in identifying the appropriate testing.
Whenever changes are made in materials, construction, configuration, application or processing methods, an
appropriate analysis of the potential impact of the change on the failure modes and performance of the stent
system shall be performed. Appropriate testing shall be conducted as deemed necessary.
The use of a control device for comparison should be considered in the evaluation of certain design attributes.
If overlapping of stents can be anticipated in clinical use (e.g. superficial femoral artery, coronary), integrity of
the stent under study in overlapping configurations should be evaluated, unless justification can be provided
for testing of individual stents. If overlapping with a different device is specifically indicated, testing should
include evaluation with the indicated device.
Testing to establish the labelled shelf-life shall be conducted by repeating appropriate tests. Justification for
the selection of tests shall be provided. For drug eluting stents, real time and accelerated testing conditions
should be used to define drug attributes for product shelf life.
1) [35] [36]
NOTE 2 Additional guidance for stability testing of drug products can be found in ICH Q1A (R2), ICH Q1B , and
[37]
ICH Q1D .
8.2 Sampling
A sampling plan shall be utilized which will ensure that adequate representation of the data has been obtained
for each parameter measured. The design characteristics of the stent (including any drugs and/or coatings),
delivery system and stent system shall be verified to be representative of the devices to be released for
distribution, including all sizes, configurations and components.
The sampling shall fully represent the range of device designs and might not necessarily require the testing of
each size. The stent sizes selected for testing shall represent the worst case combination(s) of diameter and
length for each test. A rationale shall be provided for sample selection. It might be necessary to conduct an
assessment to identify the size(s) of the device with the greatest potential for failure.
Sampling shall ensure adequate representation of the expected variability in the manufacture of devices.
For those tests with specified confidence and reliability parameters, the sample size shall have a statistical
basis. For all tests, the number of samples shall be justified.

1) International Conference on Harmonisation guidelines.
8 © ISO 2008 – All rights reserved

ISO 25539-2:2008(E)
8.3 Conditioning of test samples
All samples shall be subjected to sterilization, including multiple sterilizations, if appropriate, unless
justification is provided for use of nonsterilized products.
Samples shall be subjected to conditions that are normally encountered which might affect the test results.
Conditioning might include loading the stent on or inside the delivery catheter, preconditioning of the stent
system as recommended in the instructions for use (IFU), single or multiple passes through an anatomical
model, and deployment of the stent.
A simulated physiological environment (e.g. a temperature-controlled water bath) shall be used when
appropriate.
8.4 Reporting
For the purposes of this part of ISO 25539, reporting relates to requests from a national regulatory authority or
from a body responsible for assessing conformity.
The test report for the preclinical in vitro testing shall include an executive summary of all testing. This
summary should include identification of tests, with the rationale for the omission of any tests identified in
Annex B or the selection of alternative tests. The information provided in each test report should be based
upon a prospectively defined test protocol.
A summary of results, with acceptance criteria and any potential clinical significance of the results, should be
included and can be in tabular form. Consideration shall be given to the anatomical, physiological, and
morphological conditions of the intended use in establishing the acceptance criteria. Justification and clinical
applicability of acceptance criteria for each test shall be provided. A table of contents should be provided and
pages should be numbered sequentially.
Individual test reports should include the following information:
a) purpose: state the purpose of the test as it corresponds to this part of ISO 25539;
b) materials: list all materials (e.g. test articles with lot/serial numbers or other appropriate means of
traceability, equipment) used in performing the test, using figures and diagrams as appropriate;
c) sampling: state the sampling plan, including the basis for and the number of samples tested; selection of
test article shall be justified (e.g. sizes, conditioning);
d) acceptance criteria: state the acceptance criteria for the test results;
e) test method: describe in detail the method used to perform the test, including any prospectively defined
inspection procedures, and provide a justification for critical test parameters;
f) protocol deviations: describe any deviations and their potential significance on the interpretation of the
results;
g) expression of results: describe testing results expressed in units as indicated in the test method;
h) conclusion: state conclusions, based on comparing results to acceptance criteria, including any potential
clinical significance of these results.
ISO 25539-2:2008(E)
8.5 Delivery system and stent system
8.5.1 Ability to access
8.5.1.1 General
This covers the ability of the system to permit safe, consistent and accurate access to the intended location.
For estimating risks, the hazards to be considered include, but are not limited to, the following:
a) guidewire not crossing the lesion;
b) introducer and delivery system not matching the access site (i.e., size mismatch);
c) delivery system not advancing to target site;
d) embolism and air embolization;
e) stent dislodgement.
These hazards might result in reportable clinical events, including but not limited to the following:
⎯ access failure;
⎯ vascular trauma;
⎯ neurological deficit;
⎯ ischemia;
⎯ spinal neurological deficit;
⎯ embolization;
⎯ procedural bleeding.
Testing shall include the following items listed in 8.5.1.2 to 8.5.1.13, as appropriate to the design of the stent
system.
8.5.1.2 Bond strength
Determine the longitudinal bond strength between parts of the delivery system. All bonds shall remain intact
under recommended conditions of use. The results shall be evaluated in relation to the force(s) necessary to
access the intended location.
8.5.1.3 Component dimension compatibility
Evaluate the dimensions of the stent system for compatibility with the dimensions of recommended
accessories. All components shall be dimensionally compatible. The need for contrast to be able to pass
through the lumen of the guide catheter or introducer with the stent system in place should be considered.
8.5.1.4 Dimensional verification
Determine the appropriate dimensions for conformance with design specifications.
8.5.1.5 Dislodgement force (pre-mounted balloon expandable stents)
Determine the force required to dislodge the premounted stent from the crimped position on the non-
expanded balloon and to completely separate the stent from the non-expanded balloon during clinical use.
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ISO 25539-2:2008(E)
8.5.1.6 Flex/kink
Evaluate the ability of the stent system to bend in order to accommodate the predetermined clinically relevant
radius or angle it will be required to negotiate during access and delivery.
8.5.1.7 Profile/diameter test
Determine the maximum diameter along sections of the stent system.
8.5.1.8 Pushability
Evaluate the ability of the stent system to be pushed or positioned by an operator without undesirable bending
or buckling.
8.5.1.9 Simulated use
Evaluate the performance of the stent system using a model(s) that simulate(s) the intended use conditions.
8.5.1.10 Torquability
Evaluate the ability of the stent system to provide sufficient rotation to the distal (leading) end to deliver the
stent within the anatomy, if appropriate for the intended clinical use.
8.5.1.11 Torsional bond strength
Determine the torque/rotation required to break joints and/or materials in the appropriate delivery system
components, if appropriate for the intended clinical use. The results shall be evaluated in relation to the torque
necessary to access the system.
8.5.1.12 Trackability
Evaluate the ability of the stent system to advance through the vessel to the target site using the
recommended accessories. Evaluate the potential for displacement of the guidewire from its intended position
during the advancement of the stent system, as appropriate for the intended use of the stent (e.g. loss of side-
branch access during stenting).
8.5.1.13 Visibility
Evaluate the ability to visualize the delivery system and/ or stent system during access using fluoroscopy. The
use of other technologies for visualization shall be justified.
8.5.2 Ability to deploy
8.5.2.1 General
This covers the ability of the system to permit safe, consistent and accurate deployment of the stent.
For estimating risks, the hazards to be considered include, but are not limited to, the following:
a) inability to fully and properly deploy the stent;
b) stent dislodgement;
c) balloon failure (if applicable);
d) stent or delivery system damage;
ISO 25539-2:2008(E)
e) inadequate visualization;
f) embolism and air embolization.
These hazards might result in reportable clinical events, including, but not limited to, the following:
⎯ delivery system failure;
⎯ deployment failure;
⎯ spinal neurological deficit;
⎯ neurological deficit;
⎯ vascular trauma;
⎯ ischemia;
⎯ embolization;
⎯ damage to stent;
⎯ procedural bleeding.
Testing shall include the following items listed in 8.5.2.2 to 8.5.2.13, as appropriate to the design of the stent
system.
8.5.2.2 Bond strength
Determine the longitudinal bond strength between parts of the delivery syst
...