1、Designation: F2914 12Standard Guide forIdentification of Shelf-life Test Attributes for EndovascularDevices1This standard is issued under the fixed designation F2914; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide addresses the determination of appropriatedevice attributes for testing as part of a shelf-life study forendova
3、scular devices. Combination and biodegradable devices(for example drug-devices, biologic devices or drug biologics)may require additional considerations, depending on theirnature.1.2 This guide does not directly provide any test methodsfor conducting shelf-life testing.1.3 This standard does not pur
4、port to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Terminology2.1 Definitions:2.1.1 endovascu
5、lar devicedevice used to treat vasculardisease from within the vessel.2.1.2 productfinal packaged and sterilized device with allincluded components.2.1.3 shelf lifethe amount of real time that a fully pack-aged (and sterilized, if applicable) product can be expected toremain in storage at specified
6、conditions and maintain itscritical performance properties.3. Significance and Use3.1 The purpose of this guide is to provide a procedure fordetermining the appropriate attributes to evaluate in a shelf-lifestudy for an endovascular device.4. Procedure4.1 Shelf-life Establishment Model IntroductionT
7、he deci-sion flow chart (Fig. 1) assists study developers in selectingand justifying risk-appropriate test protocols for medical de-vices to establish shelf life. The decision flowchart is intendedto elicit questions and an appropriate rationale for testing or nottesting a particular attribute durin
8、g aging. The risk to thepatient as the device ages is one of the primary drivers. It isrecommended that all regulatory requirements and guidancesbe considered during development of the shelf-life establish-ment test plan. See Fig. 1.4.2 Question 1: “Could the device attribute change overtime?”:4.2.1
9、 Considerations in Evaluating Question 1This ques-tion must be addressed based on the device design character-istics (and also in relation to the device being packaged,sterilized, shipped and stored).4.2.1.1 Consider attributes such as the following, for ex-ample:(1) Material Properties/Characteriza
10、tionComposition;Mechanical Properties; Corrosion Resistance(2) Dimensional and Functional PropertiesDimensions;Surface Area; Foreshortening(3) Deliverability and FunctionalityBalloon Fatigue;Balloon Rated Burst; Bond Tensile Strength4.2.1.2 Various sources may provide sufficient evidence toconfirm t
11、hat some specific attributes do not change over timefor the application or that the change is not a risk to the patient.(1) Scientific literature.(2) Appropriate vendor publication.(3) In-house research.(4) Assessment of clinically accepted device.4.2.1.3 When using such data to justify why certain
12、attri-butes may not require shelf-life testing, consider all differencesbetween the subject device and the source of those data toensure applicability. For example, vendor literature may notrepresent the actual use of the material by the device manu-facturer. Additionally, further processing (for ex
13、ample, steril-ization) may change the physical or chemical attribute(s) of thematerial. Finally consider whether there are interactions(chemical or physical) that may impact your assessment.4.2.1.4 In order for testing to be applicable, the testing mustbe conducted on articles that are representativ
14、e of the finaldevice (that is, utilizing the same sterilization method and dose,1This guide is under the jurisdiction of ASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.30 on Cardiovascular Standards.Current edition approved Jan. 15
15、, 2012. Published February 2012. DOI:10.1520/F291412.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.FIG. 1 Device Aging Shelf-life Establishment Flow ChartF2914 122dimensions, material, processing conditions, and packaging). Iftest
16、articles are not identical, provide appropriate justificationfor applicability of the testing.4.2.2 Justification Based upon Scientific PrinciplesWhenone considers whether an attribute should be included in ashelf-life study, the first question is whether the attributechanges over time. There are se
17、veral device attributes that maybe driven by physical parameters of the device that would notchange over time and therefore will not require shelf-lifetesting. The assessment should be conducted using universalscientific/physical principles. In cases where the assessment isbased on universal scienti
18、fic/physical principal, appropriatereferences should be provided. In cases where justificationsmay be less obvious, data to support the scientific/physicalrationale shall be generated. Tables 1 and 2 list two groups ofdevice attributes with accompanying scientific rationale.4.2.3 Justification Based
19、 upon DataScientific principlesfor some device attributes/requirements are not readily evident.In such cases, one may generate data to support a rationale. Itmay be advantageous to conduct testing in a manner thatallows for the data to be applicable to various size devices. Inthis case, it is import
20、ant to translate the device attribute (suchas system flexibility) into the underlying size independentscientific parameters (such as Youngs modulus). Testing isthen conducted to evaluate the stability of the core scientificparameter. For each device attribute, more than one scientificparameter may b
21、e necessary to demonstrate stability over theaging period. (For simplicity of the examples, only one testparameter is illustrated in Table 3.) Each device attributeshould be evaluated to determine what scientific parametersmay be affected by aging and the appropriate testing to mitigateeach of those
22、 risks should then be conducted. The attributesevaluated must be conducted on samples that are representativeof the device; and the stability evaluation must be equal orgreater than the anticipated shelf life. Some hypotheticalexamples are printed in the remainder of this section.4.3 Question 2: “Wi
23、ll the change have an impact on safetyor performance?”Once it has been determined that a deviceattribute is likely to be affected by time and storage conditions,the second question to evaluate is whether the change poses apossible risk to the patient or product performance. Anotherway of stating the
24、 question is: “Will a change in the deviceattribute, resulting from aging, pose a significant risk to thepatient or clinician?” Risk analysis is an appropriate techniqueused to answer this question. However, since risk analysismethodologies have yet to be standardized, there is no defini-tive risk l
25、evel that can be applied universally for all devices andparameters. It will be the responsibility of individual compa-nies to carefully develop the threshold for acceptable risk.4.3.1 Basis for Risk AssessmentThe assessment of riskrelated to a device attribute may be conducted using clinicalhistory
26、(in literature or privately held) or the complaint historyof a similar device used in a similar application. Additionally,a scientific/medical argument might provide adequate informa-tion to assess the risk.4.3.2 Risk Assessment ExamplesThe following examplesof risk assessment of selected attributes
27、 are for illustrativepurposes only; this guide cannot claim to address all circum-stances and thus these examples should not be used to overlyinfluence a companys policies. When not expected to impactsafety or performance, the scientific justification shall bedocumented in detail.TABLE 1 Example Att
28、ributes Typically Impacted by AgingDevice Attribute Scientific PrincipleNylon polymer catheter tensile at break Aging of polymers can result in the breaking of chemical bondsand/or a reduction in polymer chain entanglement. Therefore thisdynamic process needs to be assessed after defined shelf-lifet
29、esting conditions.Balloon rated burst Aging of polymers can result in the breaking of chemical bondsand/or a reduction in polymer chain entanglement. Therefore thisdynamic process needs to be assessed after defined shelf- lifeconditions.Balloon fatigue Aging of polymers can result in the breaking of
30、 chemical bondsand/or a reduction in polymer chain entanglement. Therefore thisdynamic process needs to be assessed after defined shelf-lifeconditions.Stent securement Stent securement is driven by interactions between stents andballoon surfaces. Since polymers may relax after time, theengagement of
31、 these surfaces may change. Therefore this dynamicprocess needs to be assessed after defined shelf-life conditions.F2914 1235. Shelf-life Establishment Report5.1 The report shall include a complete device description,assumptions for device storage, and the device attributesconsidered for testing in
32、conducting a device aging shelf-lifeestablishment study. The decision to conduct testing or not foreach device attribute shall be reported. The rationale for whytesting of a specific device attribute was determined to not benecessary (answered “no” to Questions 1 or 2) shall bereported. The reported
33、 rationale shall provide sufficient detailto convince a person with adequate engineering/scientificexperience. References supporting rationale to not conducttesting should be provided, as appropriate. When testing of aspecific device attribute was determined to be necessary(answered “yes” to Questio
34、ns 1 and 2), no rationale needs to bereported. The following template may be used to report thedecisions and appropriate rationale for the development of thedevice aging shelf-life establishment plan. In addition, proto-cols and/or reports should also be provided for the individualshelf-life tests c
35、onducted which are used to justify attributeinclusion or exclusion.TABLE 2 Examples of Attributes Typically Not Impacted by AgingDevice Attribute Scientific PrincipleStent surface area Metals are generally stable at storage conditions. Therefore theactual dimensions and resultant calculated surface
36、area will notchange.Stent fatigue Metals are generally stable at storage conditions and therefore theactual dimensions will not change. Additionally, the microstructurewill not change under storage conditions and therefore the fatigueperformance will not change.Dimensions of hard plastics (such as h
37、ub/manifolds) Plastics such as polycarbonate which are sterilized by EthyleneOxide are in their glassy state under storage conditions, andtherefore the physical dimensions will not change over time.MR compatibility The magnetic response of an implant is driven by the magneticproperties, mass and dim
38、ensions of the metallic components. Sincethe composition of the metallic components is not altered understorage conditions with time the MR compatibility will not changeover time.Marker radiopacity The absorption of X-ray radiation is driven by the thickness andcomposition of a marker. Since the com
39、position of the marker bandis not altered under storage conditions with time, and since themarker band is stable at storage conditions and the actualdimensions will not change with time, the marker radiopacity will notchange over time.Corrosion resistance Corrosion resistance of a metal implant (e.g
40、. stent or Inferior VenaCava filter) in a known environment is determined by the surfacecomposition of the medical device. Since the surface composition ofthe metallic device is not altered with time, the corrosion resistancewill not change over time under storage conditions.F2914 124TABLE 3 Example
41、 of Data and Decision on Whether to TestDevice Attribute DataPolymer catheter flexibility Catheter flexibility is driven by multiple attributes such as the bulkmodulus of the individual components, tensile testing has beenconducted on aged polymer tubing to demonstrate the stability ofthe Youngs mod
42、ulus. Some hypothetical results are shown below:As seen in the above graph, the modulus does not change withinthe shelf-life conditions and therefore catheter flexibility does notchange.Balloon rated burst pressure Balloon burst strength is driven by multiple attributes such asultimate tensile stren
43、gth of the balloon material, the wall thickness,and the process for bonding the balloon to the catheter shaft.Testing has been conducted on aged balloon tubes to demonstratethe stability of the material strength, dimensions. Some hypotheticalresults are shown below:As seen on the above graph, the te
44、nsile strength of the balloontubes does change within the shelf-life conditions. Therefore balloonburst strength of a catheter is likely to change and will be includedin a shelf-life study.F2914 1256. Keywords6.1 aging; establishment; shelf life; shelf-life; stabilityBIBLIOGRAPHY(1) ASTM Guide F1980
45、 for Accelerated Aging of Sterile BarrierSystems for Medical Devices2(2) Non-Clinical Engineering Tests and Recommended Labeling forIntravascular Stents and Associated Delivery Systems, April 18,20103(3) Class II Special Controls Guidance Document for Certain Percuta-neous Transluminal Coronary Angi
46、oplasty (PTCA) Catheters, Sep-tember 8, 20103(4) Shelf Life of Medical Devices, April 19913(5) ISO 11346 Rubber, Vulcanized or ThermoplasticEstimation ofLife-time and Maximum Temperature of Use4(6) ISO 11607-1:2006 Packaging for Terminally Sterilized MedicalDevicesPart 1: Requirements for Materials,
47、 Sterile Barrier Sys-tems and Packaging4(7) ISO 14971 Medical DevicesApplication of Risk Management toMedical Devices4(8) ISO 25539-1 Cardiovascular ImplantsEndovascular DevicesPart 1: Endovascular Prostheses4(9) ISO 25539-2 Cardiovascular ImplantsEndovascular Devices Part2: Vascular Stents4(10) TIR
48、 17:2008Compatibility of Materials Subject to Sterilization,Section 6 and Annex GAccelerated Aging Programs52For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the stan
49、dards Document Summary page onthe ASTM website.3Available from Food and Drug Administration (FDA), 10903 New HampshireAve., Silver Spring, MD 20993-0002, http:/www.fda.gov.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from Association for the Advancement of Medical Instrumentation(AAMI), 4301 N. Fairfax Dr., Suite 301, Arlington, VA 22203-1633, http:/www.aami.org.TABLE 4 Hypothetical Example of Risk AssessmentDevice Attribute Likely to impact safety or performan
