1、Designation: F2394 07 (Reapproved 2017)Standard Guide forMeasuring Securement of Balloon Expandable VascularStent Mounted on Delivery System1This standard is issued under the fixed designation F2394; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, the year of last 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 provides guidance for the design and devel-opment of pre-test treatments, test
3、s, and test endpoints tomeasure stent securement of pre-mounted, unsheathed,balloon-expandable stent delivery systems. This guide is in-tended to aid investigators in the design, development, and invitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.1.2 This
4、guide covers the laboratory determination of theshear force required to displace or dislodge a balloon-expandable endovascular stent mounted on a delivery system.The guide proposes a set of options to consider when testingstent securement. The options cover pre-test treatments, pos-sible stent secur
5、ement tests, and relevant test endpoints. Anexample test apparatus is given in 7.1.1.3 This guide covers in vitro bench testing characterizationonly. Measured levels of securement and product design/process differentiation may be particularly influenced by selec-tions of pre-test treatments, securem
6、ent test type (for example,stent gripping method), and test endpoint. In vivo characteris-tics may also differ from in vitro results.1.4 This guide does not cover all possible pre-testtreatments, stent securement tests, or test endpoints. It isintended to provide a starting point from which to selec
7、t andinvestigate securement test options.1.5 This guide does not specify a method for mounting thestent onto the delivery system.1.6 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; theref
8、ore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard
9、 to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for th
10、eDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E1169 Practice for Conducting Ruggedness TestsE1488 Guide for Statistical Procedures to Use in Developinga
11、nd Applying Test Methods2.2 Other Documents:ISO 10555-1 Sterile Sterile Sterile, Single-use IntravascularCathetersPart 1: General Requirements3Quality System Regulation, Part VII Dept. Health and Hu-man Services, Food and Drug Administration, 21 CFRPart 820 Medical Devices; Current Good Manufacturin
12、gPractice; Final Rule. Federal Register, October 7, 19964EN 14299 Non Active Surgical ImplantsParticular Re-quirements for Cardiac and Vascular ImplantsSpecificRequirements For Arterial Stents, May 20045CDRH Guidance, Non-Clinical Tests and RecommendedLabeling for Intravascular Stents and Associated
13、 DeliverySystems, January 13, 200561This 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 Sept. 1, 2017. Published September 2017. Originallya
14、pproved in 2004. Last previous edition approved in 2013 as F2394 07 (2013).DOI: 10.1520/F2394-07R17.2For 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 standards Do
15、cument Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 204
16、01, http:/www.access.gpo.gov.5Available from British Standards Institute (BSI), 389 Chiswick High Rd.,London W4 4AL, U.K., http:/www.bsi-.6Available from Food and Drug Administration (FDA), 5600 Fishers Ln.,Rockville, MD 20857,. Http:/www.fda.gov/cdrh/ode/guidance/1545.pdf.Copyright ASTM Internation
17、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides
18、 and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1MAUDE Database73. Terminology3.1 Definitions:3.1.1 balloon expandable stent, na stent that is expandedat the treatment site by a balloon catheter. The stent material isplastically deformed by the
19、 balloon expansion such that thestent remains expanded after deflation of the balloon.3.1.2 crimp, vto secure the stent on the delivery system byradially compressing and plastically deforming the stent ontothe balloon.3.1.3 delivery system, na system similar to a balloondilatation catheter that is u
20、sed to deliver and deploy a stent atthe target site and then removed.3.1.4 displacement force, critical distance peak, na stentsecurement test endpoint characterizing the maximum forcerequired to displace the stent with respect to the balloon acritical distance. This critical distance is the minimum
21、 of thefollowing two distances. The first is the distance at which theundamaged stent could overhang the balloon body resulting ina clinically significant, incomplete end deployment. The sec-ond is the length (distance) of stent compression or bucklingthat could result in a clinically significant in
22、complete deploy-ment of the stent against the vessel walls. (See Fig. X2.1.)3.1.5 displacement force, initial, na stent securement testendpoint characterizing the initial force required to displace thestent with respect to the balloon such that the displacement isa non-recoverable movement (see 3.1.
23、15). (See Fig. X2.1.)3.1.6 displacement force, initial peak, na stent securementtest endpoint characterizing the first peak in force that occursduring or after stent displacement with respect to the balloon.(See Fig. X2.1.)3.1.7 dislodgment force, peak, na stent securement testendpoint characterizin
24、g the peak or maximum force required tocompletely dislodge the stent from the delivery system balloon.During a test, this force will occur after or coincide with theinitial displacement force. (See Fig. X2.1.)3.1.8 end flaring, na distal or proximal outward conicalopening of the diameter of the sten
25、t on the balloon. End flaringis a contributing factor to the probability that the stent maybecome caught during withdrawal into a guide catheter whiletracking through a lesion.3.1.9 failure mode effect analysis (FMEA), nan analyticalapproach to methodically determine and address all possibleproduct
26、failure modes, their associated causes, and theircriticality. Used to evaluate designs, prioritize testing, andtrack risk reducing improvements to the product.3.1.10 gauge length, nthe initial unstressed length ofcatheter tubing between the proximal end of the stent to thegrips which engage the cath
27、eter tubing.3.1.11 grips, na means of applying force to the stent andballoon catheter to displace or dislodge the stent relative to theballoon. In particular, grips refer to the end of a device whichmakes the contact with the stent. Typical grips used to applyforce to the stent include shims (as use
28、d in Figs. X2.5-X2.8);tape which sticks to the stent but not the balloon; an iris whichcan be narrowed down to allow the balloon to slip by but notthe stent; or nubs which contact the stent but not the balloon.3.1.12 guide catheter, na tube designed to transport theguide-wire and the stent delivery
29、system into the target vessel.3.1.13 guide-wire, na wire designed to aid in balloon,ultrasound, atherectomy, or stent placement during endovascu-lar procedures.3.1.14 mandrel, na wire that may be used as an alternativeto the intended guide-wire to provide support for the catheterguide-wire lumen for
30、 some test procedures.3.1.15 non-recoverable movement, na displacement of thestent relative to the balloon such that if the shearing force wasreduced to zero, the stent would remain displaced in thedirection of the shearing force relative to the initial placementon the balloon. The force at which no
31、n-recoverable movementbegins is defined as the initial displacement force (see defini-tion above).3.1.16 pre-test treatment, na treatment of the stent deliv-ery system prior to the evaluation of securement that simulatespreparatory, environmental, mechanical or other conditionsthat may be encountere
32、d prior to or during clinical use of thedevice. Examples include subjecting the devices to elevatedshipping temperature/humidity, catheter preparation per useinstructions, pre-soaking, bending treatments, tracking treat-ments (tracking fixture, see definition below) and trackingthrough lesion treatm
33、ents (lesion fixture, see definition below).3.1.17 pre-test treatment tracking fixture, na pre-test treat-ment fixture used to simulate an anatomical vasculature. Use ofthe fixture with a guide catheter, a guide-wire and the stent-balloon catheter delivery system is intended to simulate thebending a
34、nd frictional forces of tracking the device to thelesion site that may be encountered in the clinical setting. Seethe engineering diagrams in the Appendix. Note that theseengineering diagrams simulate vessels with a moderatelydifficult degree of coronary tortuousity but do not includesimulated lesio
35、ns.3.1.18 pre-test treatment lesion fixture, na pre-test treat-ment fixture used to simulate an anatomical vasculature andlesion. Use of the fixture with a guide catheter, a guide-wire,and the stent-balloon catheter delivery system is intended tosimulate the bending, frictional and mechanical resist
36、anceforces of tracking the device across the lesion site that may beencountered in the clinical setting.3.1.19 securement test, guide-type, na stent securementtest that is similar to the clinical scenario of pulling anundeployed stent delivery system back into a guide catheter,arterial sheath or hem
37、ostasis valve. Examples include guides,rings, or shims ideally designed to engage the stent end or bodybut not the catheter balloon. The shim securement test, de-scribed in Section 7, uses complementary thin, rigid plates withrounded “V” notches that are sized to circumferentially engagethe stent en
38、d but not the catheter balloon. See the engineeringdiagrams in the Appendix.7Http:/www.fda.gov/cdrh/maude.html.F2394 07 (2017)23.1.20 securement test, lesion-type, na stent securementtest that is similar to the clinical scenario of pushing or pullingan undeployed stent delivery system through or aro
39、und afibrous or calcified lesion. Examples include tape, nubs,protrusions or sandpaper ideally designed to engage the stentend or body but not the catheter balloon.4. Significance and Use4.1 The securement of the endovascular stent on the balloonis a critical parameter to ensure that the stent is sa
40、fely deliveredto or from the treatment site.4.2 This guide is intended for use by researchers andmanufacturers for the development and selection of pre-testtreatments, tests and test endpoints to measure stent secure-ment (displacement distances and dislodgment forces).4.3 This guide may be used to
41、investigate which practicalcombinations of in vitro tests best characterize clinical sce-narios.4.4 This guide should be used with discretion in choosingsecurement tests and evaluating results due to the myriadpossible combinations of clinical conditions, failure modes,and stent delivery system desi
42、gns.4.5 This guide may be of use for developing a test formeeting parts 2 and 3 of the requirements of EN 14299,Section 7.3.4.4 on Trackability.4.6 This guide may be of use for developing a test to meetsection VII-C-8 of CDRH Guidance document.5. Clinical Scenarios5.1 There are two failure modesthe
43、stent is dislodgedfrom the catheter or the stent is displaced or deformed on thecatheter such that balloon inflation delivery would not producean acceptable stent shape at the proper location. Based onreported clinical incidents, there are three causes for these twotypes of failures:5.1.1 Displaceme
44、nt or dislodgment of the stent while at-tempting to track through or position in tortuous bends, fibrousor calcified lesions, or previously implanted stents, or combi-nation thereof.5.1.2 Displacement or dislodgment of the stent on with-drawal of the undeployed stent delivery system back into thegui
45、de catheter, introducer sheath, or hemostasis valve. Thisfailure type is usually associated with failure to cross tortuousbends, fibrous or calcified lesions, or previously implantedstents, or combination thereof. It is sometimes associated withless-than-ideal seating or angled placement of the guid
46、ecatheter tip in the ostium of the vessel.5.1.3 Displacement or dislodgement of the stent due toimproper catheter preparation including mishandling or partialballoon inflation during preparation. This has been identified ina few cases where the loose, displaced, or dislodged stent wasobserved prior
47、to use but may conceivably play a role in asmall percentage of cases where dislodgment occurs in pa-tients.6. Test Method Considerations6.1 FlowchartSee Fig. 1.6.2 Development and Evaluation of Securement Tests:6.2.1 Securement test development and selection is ideallybegun through the initial use o
48、f a battery of tests measuring avariety of failure modes. These test methods may vary from asimple intuitive tactile impression of the securement forcesthrough manipulation to clinically modeled situations withguide catheters and stenosis models to in vivo animal studieswith representative anatomy a
49、nd physician handling. From asafety-risk perspective, consider how securement challengesmay occur in clinical situations, what may result from loss ofsecurement, what the severity of the outcome is to the patient,what the frequency of these situations are, and then how to testto detect these occurrences. Factors to consider in evaluatingsecurement tests include the following:6.2.1.1 Review of the MAUDE database for reported prob-lems with comparable devices.6.2.1.2 Physician surveys for clinical relevance and prob-lems with comparable devices.
