F04.30 - Cardiovascular Standards

SIGNIFICANCE AND USE
5.1 The evaluation of particulates from endovascular devices is a critical parameter to help ensure that the devices can be delivered to and from the treatment site with minimal unintended effects due to particulate generation.  
5.2 This guide is intended for the development and design of a simulated use model for the evaluation of particulate generation by those manufacturing and/or evaluating endovascular devices.  
5.3 This guide may be useful for establishment of credibility of a simulated use model as part of development testing and regulatory submission testing and filings.
SCOPE
1.1 This standard provides recommendations regarding the development of a simulated use model for particulate generation testing of endovascular devices.  
1.2 Corresponding recommendations will be provided for the coronary, peripheral, and neurovascular anatomy respectively, as these different environments each have unique challenges and considerations that should be incorporated into the model development.  
1.3 Considerations include, but are not limited to: anatomical considerations (for example, tortuosity, dimensions, disease state), working path length of the human vasculature, model/device interactions (for example, material properties, vessel straightening due to device placement), and device/device interactions (for example, use of delivery catheters and/or guide wires).  
1.4 Standardizing the model development allows for better interpretation of the test results and comparison of performance of similar medical devices.  
1.5 Explicit models for devices (or groups of devices) are not provided in this document as specific device attributes (for example, device flexibility, device material), anatomical target locations, and intended patient population can strongly impact model design. This document enables the development of a model that appropriately and sufficiently challenges the subject device with respect to particulate generation.  
1.6 While this document is intended to aid in the development and design of the simulated use model for the assessment of particulate generation, additional information regarding the evaluation of the particulate matter and particulate measurements can be found in AAMI TIR 42. Similarly, this document is not intended to address testing associated with the use of the model.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 The purpose of this guide is to provide a procedure for determining the appropriate attributes to evaluate in a shelf-life study for an endovascular device.
SCOPE
1.1 This guide addresses the determination of appropriate device attributes for testing as part of a shelf-life study for endovascular devices. Combination and biodegradable devices (for example, drug devices, biologic devices, or drug biologics) may require additional considerations, depending on their nature.  
1.2 This guide does not directly provide any test methods for conducting shelf-life testing.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ABSTRACT
This test method covers the procedure for determining the durability of ballon-expandable and self- expanding metal or alloy vascular stents. Tests are performed by exposing specimens to physiologically relevant diametric distention levels using hydrodynamic pulsatile loading. Specimens should have been deployed into a mock or elastically simulated vessel prior to testing. The test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distention and include physiological pressure tests and diameter control tests. These do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion. Test apparatus include a pressure measurement system, dimensional measurement devices, a cycle counting system, and a temperature control system.
SCOPE
1.1 These test methods cover the determination of the durability of a vascular stent or endoprosthesis by exposing it to diametric deformation by means of hydrodynamic pulsatile loading. This testing occurs on a test sample that has been deployed into a mock (elastically simulated) vessel. The test is conducted for a number of cycles to adequately establish the intended fatigue resistance of the sample.  
1.2 These test methods are applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys and endovascular prostheses with metal stents. This standard does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this test method to those products is not precluded.  
1.3 These test methods may be used for assessing stent and endovascular prosthesis durability when exposed to blood vessel cyclic diametric change. These test methods do not address other cyclic loading modes such as bending, torsion, extension, or compression.  
1.4 These test methods are primarily intended for use with physiologically relevant diametric change, however guidance is provided for hyper-physiologic diametric deformation (that is, fatigue to fracture).  
1.5 These test methods do address test conditions for curved mock vessels, however might not address all concerns.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Minimal stent recoil is a desirable feature of a stent because it minimizes the maximum diameter to which a stent must be expanded to achieve its final relaxed diameter. A stent having a high recoil must be expanded to a greater diameter to achieve its final relaxed diameter than a stent having low recoil. Practically, excessive expansion of the vessel into which the stent is to be implanted may cause tissue damage resulting in a poor immediate result or poor long-term outcome. Stent recoil is affected by intrinsic properties of the material used to construct the stent and the specific geometric design of the stent; therefore, measuring stent recoil is an essential part of evaluating the design.
SCOPE
1.1 The purpose of this test method is to quantify the percentage by which the diameter of a stent decreases from its expanded diameter while still on the delivery balloon to its relaxed diameter after deflating the balloon. This test method is appropriate for stents manufactured from a material that is plastically deformed when the stent's diameter is increased from its predeployed size to its postdeployed size by mechanical means. This test method may be performed in air at room temperature unless there is a known temperature dependence of the material, in which case, the temperature at which the test is conducted shall be stated in the report.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The securement of the endovascular stent on the balloon is a critical parameter to ensure that the stent is safely delivered to or from the treatment site.  
4.2 This guide is intended for use by researchers and manufacturers for the development and selection of pre-test treatments, tests, and test endpoints to measure stent securement (displacement distances and dislodgment forces).  
4.3 This guide may be used to investigate which practical combinations of in vitro tests best characterize clinical scenarios.  
4.4 This guide should be used with discretion in choosing securement tests and evaluating results due to the myriad possible combinations of clinical conditions, failure modes, and stent delivery system designs.  
4.5 This guide may be of use for developing a test for meeting 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 meet section VII-C-8 of CDRH Guidance document.
SCOPE
1.1 This guide provides guidance for the design and development of pre-test treatments, tests, and test endpoints to measure stent securement of pre-mounted, unsheathed, balloon-expandable stent delivery systems. This guide is intended to aid investigators in the design, development, and in vitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.  
1.2 This guide covers the laboratory determination of the shear 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 testing stent securement. The options cover pre-test treatments, possible stent securement tests, and relevant test endpoints. An example test apparatus is given in 7.1.  
1.3 This guide covers in vitro bench testing characterization only. Measured levels of securement and product design/process differentiation may be particularly influenced by selections of pre-test treatments, securement test type (for example, stent gripping method), and test endpoint. In vivo characteristics may also differ from in vitro results.  
1.4 This guide does not cover all possible pre-test treatments, stent securement tests, or test endpoints. It is intended to provide a starting point from which to select and investigate securement test options.  
1.5 This guide does not specify a method for mounting the stent onto the delivery system.  
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Vascular stents are intended for permanent implant in the human vasculature (native or graft) for the purposes of maintaining vessel patency. The dimensional attributes of vascular stents are critical parameters that aid clinicians in the selection of devices for individual patients. This guide contains a listing of those dimensional attributes that are directly related to the clinical utility and performance of these devices, along with recommendations for consistent methods of measuring these attributes and presenting the information for use in clinical decision making. This guide can be used by the manufacturers and researchers of stents to provide consistency of measurement and labeling of these dimensional characteristics. It may have use in the regulation of these devices by appropriate authorities.  
4.2 The dimensional attributes included in this guide are those that are deemed related to or possibly predictive of successful clinical performance of the stent based on prior clinical experience; however, because of the myriad patient and medical factors that influence the clinical outcome of any individual treatment, conformance of a stent and delivery system with the recommendations in this guide should not be interpreted as a guarantee of clinical success in any individual patient or group of patients.
SCOPE
1.1 This guide covers the identification of and recommended measurement methods for those dimensional attributes of vascular stents that are deemed relevant to successful clinical performance. The delivery system packaged with and labeled specifically for use during the placement of the stent is also included within the scope of this guide.  
1.2 This guide addresses only the dimensional characteristics of stents. Material property and stent functional characteristics are not addressed herein. All dimensional characteristics described in this guide refer to in vitro (“bench-top”) characterization. Because of variable patient factors, for example, vessel compliance, the actual in vivo characteristics may be slightly different.  
1.3 This guide includes recommendations generally applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents or polymeric or biodegradable stents, although the application of this guide to those products is not precluded.  
1.4 While they are not specifically included within the scope of this guide, stents indicated for placement in nonvascular locations, such as the esophagus or bile duct, also might be characterized by the methods contained herein. Likewise, this guide does not include recommendations for endovascular grafts (“stent-grafts”) or other conduit devices commonly used to treat aneurysmal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.  
1.5 This guide does not include recommendations for balloon catheters sold as stand-alone angioplasty catheters, even though some of those catheters may be used for the delivery of unmounted stents supplied without a delivery system. Requirements for angioplasty catheters are contained in standards ISO 10555-1 and ISO 10555-4.  
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.6.1 The units of measurements used throughout this guide reflect the hybrid system in common clinical use in the United States as of the time of the original approval of this guide. Since a primary purpose of this guide is to promote uniformity of labeling to facilitate the selection of devices by clinical users, the units most prefer...

SIGNIFICANCE AND USE
4.1 Absorbable cardiovascular stents provide temporary support to the vasculature and are intended to degrade and absorb over time after being implanted into the vasculature.  
4.2 The test methods used to evaluate the mechanical performance of absorbable devices are similar to those used to evaluate permanent (non-absorbable) cardiovascular devices. The absorbable-specific pre-test conditioning requirements, handling requirements before and during the test, and time-dependent mechanical property evaluations for absorbable devices are addressed here.  
4.3 As the absorbable implant degrades, the mechanical performance of the device also deteriorates. The key to achieving effective revascularization with absorbable devices is to provide an adequate level of luminal support for the time frame needed for vessel stabilization.
SCOPE
1.1 This guide covers select physical and mechanical characterizations of vascular stents with one or more absorbable components. Such absorbable stents (also referred to as vascular scaffolds) are used to provide temporary luminal support of the coronary and peripheral vasculature following interventional revascularization procedures. This guide covers devices that are fabricated from one or more degradable polymers and/or metals (from this point on referred to as “absorbable”). This guide provides a framework for evaluating the change in select physical and mechanical characteristics of absorbable stents from manufacture through their intended degradation in vivo. Specific testing recommendations are limited to existing ASTM standards for stent evaluation.  
1.2 Recommendations specific to non-absorbable stents with absorbable coatings are not within scope.  
1.3 Recommendations specific to testing absorbable stent grafts are not provided here; however, this standard has many elements applicable to testing absorbable stent grafts.  
1.4 Clinical need dictates that absorbable stents initially possess the same general dimensions and mechanical function as their non-absorbable counterparts. Thus, utilization of already established mechanical stent evaluation methods is possible when absorbable test specimens are previously conditioned under physiologically relevant temperature and humidity. As a result, this standard addresses absorbable-specific testing issues related to the mechanical and physical evaluation of these devices. The annexes in this standard provide absorbable-specific testing recommendations for evaluations where an ASTM test method for durable (that is, non-absorbable) stents is already available. Specifically, this standard provides testing recommendations for adapting the elastic recoil (F2079), dimensional attributes (F2081), securement/dislodgement (F2394), pulsatile durability (F2477), FEA of stents (F2514), three-point bending (F2606), coating/acute particulate characterization (F2743), shelf life (F2914), axial bend torsional rigidity (F2942), radial loading (F3067), design verification sampling (F3172), fatigue to fracture (F3211), and fixation durability (F3374) tests to fully absorbable devices. This guide generally describes specimen conditioning, as appropriate, for absorbable devices, which can range from none to extensive depending on the measured attribute and relevant clinical exposure conditions, including time in the in-use environment. Additional stent evaluation methods that are not addressed explicitly in this guide may require absorbable-specific provisions. The user should justify the appropriate testing for the specific absorbable material and device.  
1.4.1 While the primary purpose of this guide is to address absorbable stent-related issues specific to the tests described in 1.4, additional testing (for example, radial strength) will likely also be needed. Thus, aspects of what is presented herein may be applicable to additional relevant device attributes, such as those described in ISO 25539-1 and/or 25539-2.  
1.5 T...

SIGNIFICANCE AND USE
5.1 Upon deployment of a stent or endovascular prosthesis, the device is intended to maintain the patency of the vascular vessel. In order to maintain vessel patency, the device must deform within the in-vivo loading environment without a flow-limiting loss in lumen area. Kinking induces a severe, localized loss of lumen area, typified by a slot-like lumen shape. Device resistance to kinking can be evaluated through multiple test methods, with the appropriate selection depending on the device.  
5.2 The purpose of this standard is to outline test methods to address the resistance to kinking of stents and endovascular prostheses. In the case where no kinking is observed, the radius at which a predefined narrowing criterion (for example, 50 % diameter reduction) occurs may be considered as the kink radius of the device.  
5.3 When kink resistance properties are expected to vary along the length of the stent or endovascular prosthesis, testing should be performed at each of these sections.  
5.4 This standard is not intended to evaluate the kink resistance of devices other than stents, endovascular prostheses, and scaffolds, although the specific procedures outlined here may be used if applicable.
SCOPE
1.1 This standard addresses the kink resistance of stents and endovascular prostheses (for example, stent grafts). The standard may also be applicable to scaffolds.  
1.2 Test methods presented herein address the kink resistance of stents and endovascular protheses when exposed to bending in a single plane. While concurrent influences (for example, torque) are recognized to influence kinking properties, test methods other than single-plane bending are not addressed.  
1.3 Test methods presented herein do not specifically address kink resistance of branched (for example, bifurcated) or multicomponent endovascular prostheses, but some aspects of this standard may be applicable to their application.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The purpose of this guide is to provide guidance for selecting appropriate device size(s) and determining appropriate sample size(s) for design verification of endovascular devices. The device size(s) and sample size(s) for each design input requirement should be determined before testing. The device size(s) selected for verification testing should establish that the entire device matrix is able to achieve the design input requirements. If testing is not performed on all device sizes, justification should be provided.  
4.2 The sample size justification and statistical procedures used to analyze the data should be based on sound scientific principles and should be suitable for reaching a justifiable conclusion. Insufficient sample size may lead to erroneous conclusions more often than desired.  
4.3 Guidance regarding methodologies for determining device size selection and appropriate sample size is provided in Sections 5 and 6.
SCOPE
1.1 This guide provides guidance for selecting an appropriate device size(s) and determining an appropriate sample size(s) (that is, number of samples) for design verification testing of endovascular devices. A methodology is presented to determine which device size(s) should be selected for testing to verify the device design adequately for each design input requirement (that is, test characteristic). Additionally, different statistical approaches are presented and discussed to help guide the developer to determine and justify sample size(s) for the design input requirement being verified. Alternate methodologies for determining device size selection and sample size selection may be acceptable for design verification.  
1.2 This guide applies to physical design verification testing. This guide addresses in-vitro testing; in-vivo/animal studies are outside the scope of this guide. This guide does not directly address design validation; however, the methodologies presented may be applicable to in-vitro design validation testing. Guidance for sampling related to computational simulation (for example, sensitivity analysis and tolerance analysis) is not provided. Guidance for using models, such as design of experiments (DOE), for design verification testing is not provided. This guide does not address sampling across multiple manufacturing lots as this is typically done as process validation. Special considerations are to be given to certain tests such as fatigue (see Practice E739) and shelf-life testing (see Section 8).  
1.3 Regulatory guidance may exist for endovascular devices that should be considered for design verification device size and sample size selection.  
1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Upon deployment, at the site of the vascular stenosis, the stent establishes the patency of the lumen until vascular remodeling occurs. The radial load acting upon the stent is imparted by vessel and lesion stretch. Additionally, the vessel might be affected by excursions due to pulsation (systolic and diastolic variation), muscle-skeletal interactions due to patient movement, as well as external sources (e.g., patient is struck in the neck during a car accident). The excursions vary in magnitude and type based on the location of the vessel.  
4.2 In order to maintain vessel patency, the stent has to withstand the forces acting on it without experiencing excessive deformation, migration, or sustained collapse; therefore, it is required that the stent possess adequate resistance to these loads.  
4.3 Depending on the type of device and the clinical concern, the resistance to these loads can be presented through multiple test outputs: radial strength, collapse pressure, or chronic outward force.  
4.4 The guidelines presented here can be used in the development of test methods to determine the radial loading properties of stents. This guide provides examples of different test apparatus (equipment and tooling), radial loading curves, and calculations. Although the apparatus and methods presented can be used as a reasonable simulation of actual clinical use, they have not been demonstrated to predict the actual in vivo clinical performance of any stent.
SCOPE
1.1 This document provides guidance for developing in vitro test methods for measuring the radial strength or collapse pressure of balloon-expandable vascular stents and chronic outward force of self-expanding vascular stents.  
1.2 This guide is applicable to balloon-expandable and self-expanding stents of tubular geometry. It covers both stent and stent grafts. It does not cover bifurcated stents. It does not cover stents with non-circular cross sections or tapered stents.  
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This guide does not recommend any specific test method or apparatus for measuring the radial strength, collapse pressure, or chronic outward force. Instead, this guide provides examples of test methodologies and equipment that could be used and recommends the format for presenting test results.  
1.5 This guide covers only in vitro bench testing methods. In vivo behavior might be different.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 This guide can be used to obtain force versus deflection or midspan bending moment versus midspan curvature curves for stents and stent systems subjected to three-point bending conditions. Bending flexibility of a stent system may be a factor in its ability to track through the vascular anatomy, and may be a factor in vascular trauma along the delivery pathway distal to the guide catheter. Bending flexibility of a deployed stent may be one measure of its ability to flex with a vessel, or to conform to the natural curvature of a vessel. Bending flexibility of a delivery system may also be of interest if it is desired to assess the separate contributions of the delivery system and the mounted stent to the overall flexibility of the stent system.  
3.2 This guide is not intended to determine material properties, stent system trackability (ability of a stent system to follow a guide wire and/or guide catheter through vascular tortuosity), or stent system deliverability (ability of a stent system to deliver a stent to the implantation site(s) or through particular level(s) of vascular tortuosity). While this guide does not determine stent system trackability or deliverability, it can provide quantitative insight into how stent system bending flexibility affects trackability and deliverability. Similarly, while this guide does not determine conformability of a deployed stent, it can provide quantitative insight into how stent and/or stent system bending flexibility affects deployed stent conformability. Since this guide quantifies bending flexibility, it may be useful in determining the magnitude of bending flexibility effects on bending-related performance differences between the test article and control devices.  
3.3 The three-point bending procedures provided in this guide are intended to be used to characterize balloon-expandable stent and stent system flexibility during product development. They may not necessarily satisfy any particular requirements of nation...
SCOPE
1.1 This guide provides guidelines for quantitatively characterizing balloon-expandable stent and stent system flexibility using three-point bending procedures. Guidelines are provided for characterizing deployed stent flexibility, and for characterizing pre-deployment stent system flexibility in the region of the stent and balloon.  
1.2 This guide is not recommended for test articles that cannot be appropriately evaluated using a span length to stent outer diameter (as tested) ratio of at least 4:1. Test articles that do not meet this requirement are likely to exhibit appreciable deformation by modes other than bending.  
1.3 This guide does not provide procedures for characterizing the bending flexibility of self-expanding stents, self-expanding stent systems, endoprostheses (stent-grafts), or endoprostheses systems. However, some aspects of this guide may be useful for developing appropriate three-point bending characterization procedures for these devices. While this guide was developed with vascular stents and stent systems in mind, it may be useful for characterizing the bending flexibility of balloon-expandable stents and stent systems used in non-vascular applications.  
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Finite element analysis is a valuable tool for evaluating the performance of metallic stents and in estimating quantities such as stress, strain, and displacement due to applied external loads and boundary conditions. FEA of stents is frequently performed to determine the worst-case size for experimental fatigue (or durability) testing and differentiation of performance between designs. A finite element analysis is especially valuable in determining quantities that cannot be readily measured.
SCOPE
1.1 Purpose—This guide establishes recommendations and considerations for the development, verification, validation, and reporting of structural finite element models used in the evaluation of the performance of a metallic vascular stent design undergoing uniform radial loading. This standard guide does not directly apply to non-metallic or absorbable stents, though many aspects of it may be applicable. The purpose of a structural analysis of a stent is to determine quantities such as the displacements, stresses, and strains within a device resulting from external loading, such as crimping or during the catheter loading process, and in-vivo processes, such as expansion and pulsatile loading.  
1.2 Limitations—The analysis technique discussed in this guide is restricted to structural analysis using the finite element method. This document provides specific guidance for verification and validation (V&V) of finite element (FE) models of vascular stents subjected to uniform radial loading using ASME V&V40 as the basis for developing and executing risk-informed V&V plans.  
1.2.1 Users of this document are encouraged to read ASME V&V40 for an introduction to risk-informed V&V, and to read ASME V&V10 for further guidance on performing V&V of computational solid mechanics models. This document is not intended to cover all aspects of developing a finite element model of radial deformation of a stent. It is intended for a FE analyst with structural modeling experience.  
1.2.2 While risk-informed V&V is encouraged, it is not required. Analysts may utilize alternate V&V methods. The methodology employed should be developed by knowledgeable stakeholders with consideration as to the expectations and requirements of internal teams and external bodies that will assess the performance of the stent and the credibility of the model used to make performance predictions.  
1.2.3 If an alternative V&V method is employed, then Sections 5, 6, 7, and 10 that follow ASME V&V40 guidelines may be viewed as suggestions only. Other portions of the document that refer to question of interest, risk, and context of use may be viewed in the same manner.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for informational purposes only.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
6.1 The objective of this practice is to standardize the evaluation method for assessing the hemolytic effect of a blood pump used in extracorporeal circulation and/or circulatory assistance. By comparing the hemolysis results between a subject device and a comparator device through paired testing, a relative evaluation of hemolysis for the subject device can be made.
SCOPE
1.1 This practice covers a protocol for the assessment of the hemolytic properties of continuous, intermittent, and pulsatile flow blood pumps used in circulatory assist, including extracorporeal, percutaneous, and implantable devices. An assessment is made based on the pump's effects on the erythrocytes over a certain period of time. Adopting current practices for this assessment, a 6-hour in vitro test is performed on a pump placed in a device-specific recirculating blood loop that mimics the pressure and flow conditions of the expected worst-case clinical use of the device. If the ultimate goal of the testing is to evaluate the blood damage potential of a pump for clinical use, it is suggested that paired testing between the subject blood pump and a legally marketed comparator device be conducted using the same blood pool in a matched blood test loop so that a relative hemolysis comparison can be made.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 In vitro hemolysis test results for blood pumps may be substantially affected by donor species, sex, age, fasting, the method of harvesting, the anticoagulant properties, the period of storage, the biochemical state of the blood, and the hemoglobin and hematocrit level of blood.3,4 Therefore, standardization of proper whole blood collection and preparation for the dynamic in vitro evaluation of blood pumps is essential, and this recommended practice will allow an acceptable comparison of test results among hemolysis tests involving similar testing methods.
SCOPE
1.1 This practice covers whole blood that will be used for the in vitro performance assessment of hemolysis in blood pumps intended for clinical use.  
1.2 This practice covers the recommended standard collection, preparation, handling, storage, and utilization of whole blood for the in vitro evaluation (see Practice F1841) of the following devices:  
1.2.1 Continuous flow blood pumps (roller pumps, centrifugal pumps, axial flow pumps, etc.).  
1.2.2 Pulsatile and intermittent flow blood pumps (pneumatically driven, electro-mechanically driven, with an artificial pulse, etc.).  
1.3 The source and preparation of whole blood utilized for the dynamic in vitro evaluation of red blood cell (erythrocyte) trauma caused by blood pumps can substantially influence the hemolysis performance of these devices. Thus, standardized whole blood collection and preparation methods are required.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 It is important to consider the durability of stent designs in deformation modes that are intended to model in vivo conditions. The appropriate amplitude and number of cycles in each of the modes have to be determined independently for the particular clinical use proposed for the stent. These tests do not replicate all varieties and aspects of the deployment process nor the in vivo mechanical environment in its entirety, and as such they cannot be proofs of durability. Instead, the tests provide evidence of durability. The durability tests can also provide a means of assessing design, material or processing changes.  
5.1.1 This guide might be useful for development testing, specification acceptance testing, and regulatory submission testing and filings as it provides a basic assurance that the tests are designed, executed, and reported in a suitable fashion.  
5.1.2 If the tests are conducted using a well defined FTF methodology, they can be useful in:
5.1.2.1 Potential design improvement through identification of better and worse geometries, materials, and manufacturing processes;
5.1.2.2 Understanding product durability by estimating the effects of changes in geometry, materials, or manufacturing processes;
5.1.2.3 Estimating the safety factor relative to the amplitudes and other factors in use conditions; and
5.1.2.4 Validating finite element analysis (FEA) and fatigue life models.  
5.1.3 As stated in the scope, this guide is not intended to provide the in vivo physiologic deformation conditions to which a vascular stent can be subjected. Reliable clinical data characterizing cyclic vascular deformation may be lacking for some indications. The user should develop and justify the boundary conditions (e.g., by literature review, in vivo studies, cadaver studies, or modeling of stent vessel interaction) for the chosen durability bench tests. Additional conditions that may be considered include vessel calcification, vessel taper, eccentric lesions, d...
SCOPE
1.1 This guide includes three separate cyclic deformation durability guides related to vascular stents: bending, axial, and torsional.  
1.2 This guide does not address flat plate, local crush durability, or multi-mode testing. Although this guide does not address multi-mode testing, the information included herein could be applicable to developing this type of test.  
1.3 This guide applies to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents (i.e., stents with a surface layer of an additional material(s)), monolithically polymeric stents, or absorbable stents, although the application of this standard to those products is not precluded.  
1.4 This guide applies to endovascular grafts (“stent-grafts”) and other conduit products commonly used to treat aneurismal disease, peripheral vessel trauma, or to provide vascular access. The information provided herein does not address all issues related to testing of these devices.  
1.5 This guide is applicable to testing of stent(s) (or a representative portion of a stent). While durability testing of coupon samples (e.g., a scaled-up portion of the stent structure) can provide useful information, it is not within the scope of this guide.  
1.6 This guide applies to in vitro modeling of stent durability from non-radial arterial motions. Such motions may arise from musculoskeletal activities, including walking and breathing, and cardiac motion. Test Methods F2477 addresses pulsatile (i.e., radial) durability of vascular stents.  
1.7 This guide does not provide the in vivo physiologic deformation conditions for a vascular stent. It is incumbent upon the user of the standard to develop and justify these boundary conditions (e.g., by literature review, in vivo studies, cadaver studies, or modeling of stent vessel interaction) in these durability bench tests. Additional ...

SIGNIFICANCE AND USE
5.1 Once implanted, active fixation systems are subjected to cyclic loading that can be caused by blood flow, musculoskeletal motion, and other sources. The focus of this document is on axial loading caused by hemodynamics. However, depending on the device design other loading modes could influence AFC or attachment mechanism durability (e.g., radial dilatation could lead to longitudinal foreshortening and axial loading on an active fixation system). Damage to AFCs and/or attachment mechanisms may not necessarily lead to device malfunction, but could cause embolization of portions of the device, device migration, endoleaks, or other patient complications (1-4).4 Therefore, durability testing of AFCs and attachment mechanisms is important to ensure that these components are capable of maintaining structural integrity for a defined lifetime.  
5.1.1 A test method developed following this standard guide can be used to determine the durability of AFCs and/or attachment mechanisms under the desired loading which can be used to assess conformance to product specifications, consensus standards, and guidance documents as well as to support regulatory submissions, quality control, and manufacturing.  
5.2 This guide provides examples and recommendations so that users can develop an appropriate active fixation durability test for their device design that mechanically challenges either the AFC, the attachment mechanism, or both simultaneously. It should be recognized that both AFCs and attachment mechanisms need to be evaluated to fully characterize active fixation system durability for design verification testing. While testing of the entire active fixation system may typically be preferable, this guide recognizes that there might be situations where this is not practical or desired and allows for independent testing of AFCs and attachment mechanisms. This guide does not contain an exhaustive list of test methods for active fixation durability and methods not included herei...
SCOPE
1.1 This guide addresses how to conduct in vitro durability testing on active fixation components (AFCs) and attachment mechanisms of endovascular prostheses. It does not address the durability of fixation systems that reside solely within the vessel lumen to resist device migration (e.g, radial force and friction, adhesives, or geometric fit).  
1.2 This guide was developed to address active fixation durability for aortic stent grafts. It is not intended to address fixation durability for other endovascular prostheses such as inferior vena cava filters, transcatheter heart valves, barbed venous stents, ancillary fixation devices (e.g, staples or adhesives), or cardiac devices (e.g., left atrial appendage device or mitral repair device). However, some of the techniques and guidance within may be applicable to the in vitro testing of those other devices.  
1.3 This guide does not directly apply to implants with absorbable AFCs although many aspects of this standard are applicable to those products.  
1.4 This guide does not provide the in vivo physiologic loading conditions for endovascular prostheses. It is the responsibility of the user to determine the loading or deformation conditions for their particular device and indication. Typically, an axial loading (force or displacement) mode caused by hemodynamics is used, although other modes are possible and should be considered.  
1.5 This guide does not recommend any specific test method or apparatus for evaluating active fixation durability. It is recognized that there are multiple valid ways to conduct active fixation durability testing and as such this guide provides general recommendations and topics to consider so that users can successfully develop a test plan for their device.  
1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 This standard does not purport to address al...

SIGNIFICANCE AND USE
5.1 The shedding of the coating from a vascular stent can alter its clinical safety and/or therapeutic benefit. Clinical performance (for example, drug elution) may be affected by particulate generation from the coated stent system and coating defects. This document provides guidance for coating inspection and acute particulate characterization of drug eluting vascular stents. Information about the potential for shedding can be gained during bench testing. The general guidelines presented here may be used for writing detailed protocols for specific products at the various stages of the product development process. Such testing may be performed during device development, design validation testing, lot-release testing, and/or stability testing although different requirements may apply at each stage. These suggested methods may represent a reasonable simulation of clinical usage. When establishing the coating inspection and acute particulate characterization testing conditions, the current clinical usage/practice (for example, post-dilation, overlapping stents) and the instructions for use (IFU), as applicable, should be considered. While methods for chronic particulate characterization and coating inspection have not been established, these suggested methods may be helpful in the development of chronic methods. Testing in accordance with recommendations in this guide will generate data that may lead to further improvements in the method and its validation, as well as possible advancements in device design and performance. See also FDA Guidance for Industry and FDA Staff and AAMI TIR42:2010.
SCOPE
1.1 This guide describes recommended in vitro test procedures for coating inspection and acute particulate characterization of coated drug-eluting vascular (balloon-expandable and self-expanding) stent systems.  
1.2 Recommended practices for coating inspection and acute particulate characterization include baseline (deployment) testing and simulated use testing. This guide describes the capture and analysis of particulates. This guide describes the inspection of the coated stent surface. This guide was developed for characterization and not intended for production release testing of coated drug-eluting vascular stent systems although some sections may be appropriate.  
1.3 Chronic particulate characterization and coating inspection are not included herein.  
1.4 Coating systems specifically designed to degrade or otherwise intentionally separate themselves from the permanent stent structure may not be fully addressed herein.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The methods described herein allow for in-vitro characterization of DCB drug coating attributes that, along with pre-clinical and clinical safety and effectiveness data, establish that the DCBs, with the characterized coating attributes, are safe and effective. Clinical safety and therapeutic benefit may be affected by non-uniform distribution of the active pharmaceutical ingredient, coating anomalies on the device, and particulate release. Variability in drug coating may result in insufficient or excessive drug availability and inconsistent device performance.  
5.2 Individual characterization tests may not have direct clinical relevance, although bench-based characterization results can be combined with other data to provide insight to characteristics that influence clinical safety and effectiveness. Bench testing is performed under repeatable and controlled conditions, providing information about drug coating integrity, thickness, uniformity, particulate shedding, particulate identity, and particulate crystallinity.  
5.3 Distribution of the drug coating is characterized by coating integrity, thickness, and uniformity. Particulate counts can provide a measure of manufacturing repeatability, and may provide an indication of in vivo safety if simulated use particulates and in vivo particulates are shown to be similar, or if particulate testing results are correlated to in vivo safety. Chemical identity of particulates and crystallinity may further advise the kinetics related to the potential for particulate persistence, dissolution or other characteristics which may relate to in vivo safety. Conducting this testing and gathering the data further allows for the potential comparison of devices (e.g., demonstrating equivalence between pre-clinical and clinical devices for these coating attributes).  
5.4 The methods described in this guide are for characterization purposes and are not intended for production release testing of drug coated balloon catheters. How...
SCOPE
1.1 This guide describes recommended acute in-vitro characterization methods for drug coated balloon (DCB) coatings. These methods include: coating integrity, coating thickness, drug coating uniformity, and released particulates. Specifically, this guide details:  
1.1.1 Characterization of integrity by inspection of the coated balloon surface.  
1.1.2 Measurement of coating thickness.  
1.1.3 Quantitation of drug coating uniformity (uniformity of drug distribution over the balloon surface) longitudinally and circumferentially.  
1.1.4 Quantitation of the number of particulates released, in various size ranges, during simulated use testing (insertion, tracking, deployment, retraction, and withdrawal) along with chemical and crystallinity characterization of particulates.  
1.2 This document does not address:  
1.2.1 Mechanical testing of drug coated balloons (DCBs).  
1.2.2 Drug substance evaluation (e.g., assay, related substances, uniformity of dosage units) of DCBs.  
1.2.3 Production release and stability testing, although some sections may be applicable in whole or in part.  
1.2.4 Standard analytical testing (e.g., drug content, drug related substances, drug uniformity of dosage).  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to T...

SIGNIFICANCE AND USE
5.1 Use of this Methodology:  
5.1.1 This guide provides a compendium of information on methods to use fracture data, fatigue life models, and statistical techniques to estimate the structural fatigue durability of an implantable medical device under anticipated in vivo loading modes. The methodology for high-cycle fatigue assessment relies on hyper-physiological tests intended to cause device fractures. Using the FtF methodology, fractures should not be avoided during testing; instead they provide the information required to statistically assess device longevity under a wide variety of physiological and hyper-physiological test conditions.  
5.1.2 Through evaluation of fracture locations, the geometries after fractures, and the use conditions of the device, this guide may be used to help assess device safety.  
5.1.3 This guide may be used to help assess differences in fatigue life between different devices or device histories. The effects on fatigue life due to changes to a device’s geometry, processing, or material may be assessed using this guide.  
5.1.4 Users of this guide must keep in mind that bench tests are simulations of in-use conditions. Adherence to this guide may not guarantee that results translate to individual clinical scenarios. Therefore, in assessing a device’s fatigue performance, the results from Fatigue to Fracture testing should be reviewed in combination with other available data, such as animal studies, clinical experience, and computational simulations.  
5.2 Significance of this Methodology:  
5.2.1 While the FtF methodology applies only to bench tests, it can provide insights into device behavior that would not necessarily be apparent in clinical studies that typically focus on patient outcomes. After appropriate boundary conditions such as loadings, fixturing, and materials have been determined, the FtF methodology can provide extensive information on the expected longevity of a device in a period 10 to 1000 times shorter than ...
SCOPE
1.1 This guide is intended to provide an experimental methodology to assess and determine the structural fatigue life of implantable cardiovascular medical devices.  
1.2 This guide is also intended to provide methodologies to determine statistical bounds on fatigue life at in vivo use conditions using measured fatigue life derived in whole or in part from hyper-physiological testing to fracture.  
1.3 This guide may be used to assess or characterize device durability during design development and for testing to device product specifications.  
1.4 Fretting, wear, creep-fatigue, and absorbable materials are outside the scope of this guide, though elements of this guide may be applicable.  
1.5 As a guide, this document provides direction but does not recommend a specific course of action. It is intended to increase the awareness of information and approaches. This guide is not a test method. This guide does not establish a standard practice to follow in all cases.  
1.6 This guide is meant as a complement to other regulatory and device-specific guidance documents or standards and it does not supersede the recommendations or requirements of such documents.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
6.1 The objective of this practice is to standardize the evaluation method for assessing the hemolytic effect of a blood pump used in extracorporeal circulation and/or circulatory assistance. By comparing the hemolysis results between a subject device and a comparator device through paired testing, a relative evaluation of hemolysis for the subject device can be made.
SCOPE
1.1 This practice covers a protocol for the assessment of the hemolytic properties of continuous, intermittent, and pulsatile flow blood pumps used in circulatory assist, including extracorporeal, percutaneous, and implantable devices. An assessment is made based on the pump's effects on the erythrocytes over a certain period of time. Adopting current practices for this assessment, a 6-hour in vitro test is performed on a pump placed in a device-specific recirculating blood loop that mimics the pressure and flow conditions of the expected worst-case clinical use of the device. If the ultimate goal of the testing is to evaluate the blood damage potential of a pump for clinical use, it is suggested that paired testing between the subject blood pump and a legally marketed comparator device be conducted using the same blood pool in a matched blood test loop so that a relative hemolysis comparison can be made.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ABSTRACT
This test method covers the procedure for determining the durability of ballon-expandable and self- expanding metal or alloy vascular stents. Tests are performed by exposing specimens to physiologically relevant diametric distention levels using hydrodynamic pulsatile loading. Specimens should have been deployed into a mock or elastically simulated vessel prior to testing. The test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distention and include physiological pressure tests and diameter control tests. These do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion. Test apparatus include a pressure measurement system, dimensional measurement devices, a cycle counting system, and a temperature control system.
SCOPE
1.1 These test methods cover the determination of the durability of a vascular stent by exposing it to physiologically relevant diametric distension levels by means of hydrodynamic pulsatile loading. This testing occurs on a stent test specimen that has been deployed into a mock (elastically simulated) vessel. The typical duration of this test is 10 years of equivalent use (at 72 beats per minute), or at least 380 million cycles.  
1.2 These test methods are applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this test method to those products is not precluded.  
1.3 These test methods do not include recommendations for endovascular grafts (“stent-grafts”) or other conduit products commonly used to treat aneurismal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.  
1.4 These test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distension. These test methods do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion.  
1.5 These test methods do not address test conditions for curved mock vessels.  
1.6 These test methods do not address test conditions for overlapping stents.  
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 General Caveat—This document contains guidance for testing as is currently carried out in most laboratories. Other testing techniques may prove to be more effective and are encouraged. Whichever technique is used, it is incumbent upon the tester to justify the use of the particular technique, instrument, and protocol. This includes the choice of and proper calibration of all measuring devices. Deviations from any of the suggestions in this document may be appropriate but may require the same level of comprehensive justification that the techniques described herein will require.  
1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 The purpose of this guide is to provide a procedure for determining the appropriate attributes to evaluate in a shelf-life study for an endovascular device.
SCOPE
1.1 This guide addresses the determination of appropriate device attributes for testing as part of a shelf-life study for endovascular devices. Combination and biodegradable devices (for example drug-devices, biologic devices or drug biologics) may require additional considerations, depending on their nature.  
1.2 This guide does not directly provide any test methods for conducting shelf-life testing.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The test results are substantially affected by donor species and age, the method of harvesting, the period of storage, the biochemical state of the blood, and the hemoglobin and hematocrit level of blood.3,4 Therefore, standardization of proper blood usage for in vitro evaluation of blood pumps is essential, and this recommended practice will allow a universal comparison of test results.  
5.2 Drawing several units of blood from healthy cattle does not affect them or their health. Therefore, bovine blood is strongly suggested for usage in experimental evaluation of blood damage. Mixing two donor sources of blood should be avoided in hemolysis tests because the mixture may induce added hemolysis or a change in red cell resistance against trauma.
SCOPE
1.1 This practice covers blood that will be used for  in vitro performance assessments of blood pumps. These assessments include the hemolytic properties of the devices.  
1.2 This practice covers the utilization of blood for the in vitro evaluation of the following devices:  
1.2.1 Continuous flow rotary blood pumps (roller pumps, centrifugal pumps, axial flow pumps, and so forth) (see Practice F1841).  
1.2.2 Pulsatile blood pumps (pneumatically driven, electromechanically driven, and so forth).  
1.3 The source of blood utilized for in vitro evaluation of blood trauma (that is, hemolysis caused by the blood pumps, due to the pump design, construction, and materials used) substantially influences the results of the performance of these devices. Thus, a standardized blood source is required.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The securement of the endovascular stent on the balloon is a critical parameter to ensure that the stent is safely delivered to or from the treatment site.  
4.2 This guide is intended for use by researchers and manufacturers for the development and selection of pre-test treatments, tests and test endpoints to measure stent securement (displacement distances and dislodgment forces).  
4.3 This guide may be used to investigate which practical combinations of in vitro tests best characterize clinical scenarios.  
4.4 This guide should be used with discretion in choosing securement tests and evaluating results due to the myriad possible combinations of clinical conditions, failure modes, and stent delivery system designs.  
4.5 This guide may be of use for developing a test for meeting 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 meet section VII-C-8 of CDRH Guidance document.
SCOPE
1.1 This guide provides guidance for the design and development of pre-test treatments, tests, and test endpoints to measure stent securement of pre-mounted, unsheathed, balloon-expandable stent delivery systems. This guide is intended to aid investigators in the design, development, and in vitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.  
1.2 This guide covers the laboratory determination of the shear 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 testing stent securement. The options cover pre-test treatments, possible stent securement tests, and relevant test endpoints. An example test apparatus is given in 7.1.  
1.3 This guide covers in vitro bench testing characterization only. Measured levels of securement and product design/process differentiation may be particularly influenced by selections of pre-test treatments, securement test type (for example, stent gripping method), and test endpoint. In vivo characteristics may also differ from in vitro results.  
1.4 This guide does not cover all possible pre-test treatments, stent securement tests, or test endpoints. It is intended to provide a starting point from which to select and investigate securement test options.  
1.5 This guide does not specify a method for mounting the stent onto the delivery system.  
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Minimal stent recoil is a desirable feature of a stent because it minimizes the maximum diameter to which a stent must be expanded to achieve its final relaxed diameter. A stent having a high recoil must be expanded to a greater diameter to achieve its final relaxed diameter than a stent having low recoil. Practically, excessive expansion of the vessel into which the stent is to be implanted may cause tissue damage resulting in a poor immediate result or poor long-term outcome. Stent recoil is affected by intrinsic properties of the material used to construct the stent and the specific geometric design of the stent; therefore, measuring stent recoil is an essential part of evaluating the design.
SCOPE
1.1 The purpose of this test method is to quantify the percentage by which the diameter of a stent decreases from its expanded diameter while still on the delivery balloon to its relaxed diameter after deflating the balloon. This test method is appropriate for stents manufactured from a material that is plastically deformed when the stent's diameter is increased from its predeployed size to its postdeployed size by mechanical means. This test method may be performed in air at room temperature unless there is a known temperature dependence of the material, in which case, the temperature at which the test is conducted shall be stated in the report.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
6.1 The objective of this practice is to standardize the evaluation method for detecting the hemolytic effect of a continuous flow blood pump used in extracorporeal circulation and circulatory assistance.
SCOPE
1.1 This practice covers a protocol for the assessment of the hemolytic properties of continuous flow blood pumps used in extracorporeal or implantable circulatory assist. An assessment is made based on the pump's effects on the erythrocytes over a certain period of time. For this assessment, a recirculation test is performed with a pump for 6 h.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Vascular stents are intended for permanent implant in the human vasculature (native or graft) for the purposes of maintaining vessel patency. The dimensional attributes of vascular stents are critical parameters that aid clinicians in the selection of devices for individual patients. This guide contains a listing of those dimensional attributes that are directly related to the clinical utility and performance of these devices, along with recommendations for consistent methods of measuring these attributes and presenting the information for use in clinical decision making. This guide can be used by the manufacturers and researchers of stents to provide consistency of measurement and labeling of these dimensional characteristics. It may have use in the regulation of these devices by appropriate authorities.  
4.2 The dimensional attributes included in this guide are those that are deemed related to or possibly predictive of successful clinical performance of the stent, based on prior clinical experience; however, because of the myriad patient and medical factors that influence the clinical outcome of any individual treatment, conformance of a stent and delivery system with the recommendations in this guide should not be interpreted as a guarantee of clinical success in any individual patient or group of patients.
SCOPE
1.1 This guide covers the identification of and recommended measurement methods for those dimensional attributes of vascular stents that are deemed relevant to successful clinical performance. The delivery system packaged with and labeled specifically for use during the placement of the stent is also included within the scope of this guide.  
1.2 This guide addresses only the  dimensional characteristics of stents. Material property and stent functional characteristics are not addressed herein. All dimensional characteristics described in this guide refer to in vitro (“bench-top”) characterization. Because of variable patient factors, for example, vessel compliance, the actual in vivo characteristics may be slightly different.  
1.3 This guide includes recommendations generally applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents or polymeric or biodegradable stents, although the application of this guide to those products is not precluded.  
1.4 While they are not specifically included within the scope of this guide, stents indicated for placement in nonvascular locations, such as the esophagus or bile duct, also might be characterized by the methods contained herein. Likewise, this guide does not include recommendations for endovascular grafts (“stent-grafts”) or other conduit devices commonly used to treat aneurysmal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.  
1.5 This guide does not include recommendations for balloon catheters sold as stand-alone angioplasty catheters, even though some of those catheters may be used for the delivery of unmounted stents supplied without a delivery system. Requirements for angioplasty catheters are contained in standards ISO 10555-1 and ISO 10555-4.  
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.6.1 The units of measurements used throughout this guide reflect the hybrid system in common clinical use in the United States as of the time of the original approval of this guide. Since a primary purpose of this guide is to promote uniformity of labeling to facilitate the selection of devices by clinical users, the units most preferred by users wer...

SIGNIFICANCE AND USE
4.1 The purpose of this guide is to provide guidance for selecting appropriate device size(s) and determining appropriate sample size(s) for design verification of endovascular devices. The device size(s) and sample size(s) for each design input requirement should be determined before testing. The device size(s) selected for verification testing should establish that the entire device matrix is able to achieve the design input requirements. If testing is not performed on all device sizes, justification should be provided.  
4.2 The sample size justification and statistical procedures used to analyze the data should be based on sound scientific principles and should be suitable for reaching a justifiable conclusion. Insufficient sample size may lead to erroneous conclusions more often than desired.  
4.3 Guidance regarding methodologies for determining device size selection and appropriate sample size is provided in Sections 5 and 6.
SCOPE
1.1 This guide provides guidance for selecting an appropriate device size(s) and determining an appropriate sample size(s) (that is, number of samples) for design verification testing of endovascular devices. A methodology is presented to determine which device size(s) should be selected for testing to verify the device design adequately for each design input requirement (that is, test characteristic). Additionally, different statistical approaches are presented and discussed to help guide the developer to determine and justify sample size(s) for the design input requirement being verified. Alternate methodologies for determining device size selection and sample size selection may be acceptable for design verification.  
1.2 This guide applies to physical design verification testing. This guide addresses in-vitro testing; in-vivo/animal studies are outside the scope of this guide. This guide does not directly address design validation; however, the methodologies presented may be applicable to in-vitro design validation testing. Guidance for sampling related to computational simulation (for example, sensitivity analysis and tolerance analysis) is not provided. Guidance for using models, such as design of experiments (DOE), for design verification testing is not provided. This guide does not address sampling across multiple manufacturing lots as this is typically done as process validation. Special considerations are to be given to certain tests such as fatigue (see Practice E739) and shelf life testing (see Section 8).  
1.3 Regulatory guidance may exist for endovascular devices that should be considered for design verification device size and sample size selection.  
1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 Upon deployment, at the site of the vascular stenosis, the stent establishes the patency of the lumen until vascular remodeling occurs. The radial load acting upon the stent is imparted by vessel and lesion stretch. Additionally, the vessel might be affected by excursions due to pulsation (systolic and diastolic variation), muscle-skeletal interactions due to patient movement, as well as external sources (e.g., patient is struck in the neck during a car accident). The excursions vary in magnitude and type based on the location of the vessel.  
4.2 In order to maintain vessel patency, the stent has to withstand the forces acting on it without experiencing excessive deformation, migration, or sustained collapse; therefore, it is required that the stent possess adequate resistance to these loads.  
4.3 Depending on the type of device and the clinical concern, the resistance to these loads can be presented through multiple test outputs: radial strength, collapse pressure, or chronic outward force.  
4.4 The guidelines presented here can be used in the development of test methods to determine the radial loading properties of stents. This guide provides examples of different test apparatus (equipment and tooling), radial loading curves, and calculations. Although the apparatus and methods presented can be used as a reasonable simulation of actual clinical use, they have not been demonstrated to predict the actual in vivo clinical performance of any stent.
SCOPE
1.1 This document provides guidance for developing in vitro test methods for measuring the radial strength or collapse pressure of balloon-expandable vascular stents and chronic outward force of self-expanding vascular stents.  
1.2 This guide is applicable to balloon-expandable and self-expanding stents of tubular geometry. It covers both stent and stent grafts. It does not cover bifurcated stents. It does not cover stents with non-circular cross-sections or tapered stents.  
1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This guide does not recommend any specific test method or apparatus for measuring the radial strength, collapse pressure, or chronic outward force. Instead, this guide provides examples of test methodologies and equipment that could be used and recommends the format for presenting test results.  
1.5 This guide covers only in vitro bench testing methods. In vivo behavior might be different.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
3.1 This guide can be used to obtain force versus deflection or midspan bending moment versus midspan curvature curves for stents and stent systems subjected to three-point bending conditions. Bending flexibility of a stent system may be a factor in its ability to track through the vascular anatomy, and may be a factor in vascular trauma along the delivery pathway distal to the guide catheter. Bending flexibility of a deployed stent may be one measure of its ability to flex with a vessel, or to conform to the natural curvature of a vessel. Bending flexibility of a delivery system may also be of interest if it is desired to assess the separate contributions of the delivery system and the mounted stent to the overall flexibility of the stent system.  
3.2 This guide is not intended to determine material properties, stent system trackability (ability of a stent system to follow a guide wire and/or guide catheter through vascular tortuosity), or stent system deliverability (ability of a stent system to deliver a stent to the implantation site(s) or through particular level(s) of vascular tortuosity). While this guide does not determine stent system trackability or deliverability, it can provide quantitative insight into how stent system bending flexibility affects trackability and deliverability. Similarly, while this guide does not determine conformability of a deployed stent, it can provide quantitative insight into how stent and/or stent system bending flexibility affects deployed stent conformability. Since this guide quantifies bending flexibility, it may be useful in determining the magnitude of bending flexibility effects on bending-related performance differences between the test article and control devices.  
3.3 The three-point bending procedures provided in this guide are intended to be used to characterize balloon-expandable stent and stent system flexibility during product development. They may not necessarily satisfy any particular requirements of nation...
SCOPE
1.1 This guide provides guidelines for quantitatively characterizing balloon-expandable stent and stent system flexibility using three-point bending procedures. Guidelines are provided for characterizing deployed stent flexibility, and for characterizing pre-deployment stent system flexibility in the region of the stent and balloon.  
1.2 This guide is not recommended for test articles that cannot be appropriately evaluated using a span length to stent outer diameter (as tested) ratio of at least 4:1. Test articles that do not meet this requirement are likely to exhibit appreciable deformation by modes other than bending.  
1.3 This guide does not provide procedures for characterizing the bending flexibility of self-expanding stents, self-expanding stent systems, endoprostheses (stent-grafts), or endoprostheses systems. However, some aspects of this guide may be useful for developing appropriate three-point bending characterization procedures for these devices. While this guide was developed with vascular stents and stent systems in mind, it may be useful for characterizing the bending flexibility of balloon-expandable stents and stent systems used in non-vascular applications.  
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.

SIGNIFICANCE AND USE
4.1 Finite element analysis is a valuable method for evaluating the performance of metallic stents and in quantifying quantities such as internal stresses, internal strains, and deformation patterns due to applied external loads and boundary conditions. Many times an analysis is performed to correlate to and plan experimental tests. A finite element analysis is especially valuable in determining quantities that cannot be readily measured.
SCOPE
1.1 Purpose—This guide establishes general requirements and considerations for the development of finite element models used in the evaluation of the performance of a metallic vascular stent design under uniform radial loading. Suggested criteria are provided for evaluating the typical cases of metallic stents under uniform radially oriented and pulsatile loading. Recommended procedures for checking and validating the finite element model(s) are provided as a means to assess the model and analysis results. Finally, the recommended content of an engineering report covering the mechanical simulations is presented.  
1.2 Limits:
1.2.1 This guide is limited in discussion to the finite element structural analysis of metallic stents of the following types:
1.2.1.1 Plastically deformable metal stents.
1.2.1.2 Self-expanding metal stents.  
1.2.1.3 Plastically deformable metal portions of covered stents.
1.2.1.4 Metal portions of self-expanding covered metal stents.  
1.2.2 The emphasis of the techniques described in this guide is intended for both elasto-plastic materials such as stainless steel, and superelastic materials such as nitinol. Unique concerns associated with stents designed for shape memory behavior are not addressed within this guide.  
1.2.3 This guide does not consider changes to possible time varying conditions or different loadings related to vascular remodeling.  
1.2.4 This guide is restricted to cases that involve the application of uniform radially oriented loading.  
1.2.5 This guide does not provide guidance in the application or interpretation of FEA in determining fatigue life.  
1.2.6 This guide is not intended to include complete descriptions of the finite element method, nor its theoretical basis and formulation.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

SIGNIFICANCE AND USE
4.1 Absorbable cardiovascular stents provide temporary support to the vasculature and are intended to degrade and absorb over time after being implanted into the vasculature.  
4.2 The test methods used to evaluate the mechanical performance of absorbable devices are similar to those used to evaluate permanent (non-absorbable) cardiovascular devices. The absorbable-specific pre-test conditioning requirements, handling requirements before and during the test, and time-dependent mechanical property evaluations for absorbable devices are addressed here.  
4.3 As the absorbable implant degrades, the mechanical performance of the device also deteriorates. The key to achieving effective revascularization with absorbable devices is to provide an adequate level of luminal support for the time frame needed for vessel stabilization.
SCOPE
1.1 This Guide covers select physical and mechanical characterizations of vascular stents with one or more absorbable components. Such absorbable stents (also referred to as vascular scaffolds) are used to provide temporary luminal support of the coronary and peripheral vasculature following interventional revascularization procedures. This Guide covers devices that are fabricated from one or more degradable polymers and/or metals (from this point on referred to as “absorbable”). This Guide provides a framework for evaluating the change in select physical and mechanical characteristics of absorbable stents from manufacture through their intended degradation in vivo. Specific testing recommendations are limited to existing ASTM standards for stent evaluation.  
1.2 Recommendations specific to non-absorbable stents with absorbable coatings are not within scope.  
1.3 Recommendations specific to testing absorbable stent grafts are not provided here, however this standard has many elements applicable to testing absorbable stent grafts.  
1.4 Clinical need dictates that absorbable stents initially possess the same general dimensions and mechanical function as their non-absorbable counterparts. Thus, utilization of already established mechanical stent evaluation methods is possible when absorbable test specimens are previously conditioned under physiologically relevant temperature and humidity. As a result, this standard addresses absorbable-specific testing issues related to the mechanical and physical evaluation of these devices. This standard is limited to providing absorbable-specific testing recommendations for evaluations where an ASTM method for durable (i.e., non-absorbable) stents is already available. Specifically, this standard provides testing recommendations for adapting the elastic recoil (ASTM F2079), securement/dislodgement (ASTM F2394), and three-point bending (ASTM F2606) tests to fully absorbable devices. This guide generally describes specimen conditioning, as appropriate, for absorbable devices, which can range from none to extensive – depending on the measured attribute and relevant clinical exposure conditions, including time in the in-use environment. There are additional stent evaluation methods that are not addressed explicitly in this guide, e.g., chronic durability, that may require absorbable-specific provisions. The user should justify the appropriate testing for the specific polymer and device.  
1.4.1 While the primary purpose of this guide is to address absorbable stent-related issues specific to the tests described in Section 1.3, additional testing (e.g., radial strength) will likely also be needed. Thus, aspects of what is presented herein may be applicable to additional relevant device attributes, such as those described in ISO 25539-1 and/or 25539-2.  
1.5 This Guide may not be appropriate for all absorbable devices, for example those that possess limited hydrolytic or corrosion susceptibility and degrade in vivo primarily through enzymatic action. The user is cautioned to consider the appropriateness of the standard in view of ...

SIGNIFICANCE AND USE
5.1 It is important to consider the durability of stent designs in deformation modes that are intended to model in vivo conditions. The appropriate amplitude and number of cycles in each of the modes has to be determined independently for the particular clinical use proposed for the stent. These tests do not replicate all varieties and aspects of the deployment process and the in vivo mechanical environment so they cannot be proofs of durability. Instead, the tests provide evidence of durability. The durability tests can also provide a means of assessing design, material or processing changes.  
5.1.1 This guide might be useful for development testing, specification acceptance testing, and regulatory submission testing and filings as it provides a basic assurance that the tests are designed, executed, and reported in a suitable fashion.  
5.1.2 If the tests are conducted using a well-defined FTF methodology, they can be useful in:
5.1.2.1 Potential design improvement through identification of better and worse geometries, materials, and manufacturing processes;
5.1.2.2 Understanding product durability by estimating the effects of changes in geometry, materials, or manufacturing processes;
5.1.2.3 Estimating the safety factor relative to the amplitudes and other factors in use conditions; and  
5.1.2.4 Validating finite element analysis (FEA) and fatigue life models.  
5.1.3 As stated in the scope, this guide is not intended to provide the in vivo physiologic deformation conditions that a vascular stent can be subjected. Reliable clinical data characterizing cyclic vascular deformation may be lacking for some indications. The user should develop and justify the boundary conditions (e.g., literature review, in vivo studies, cadaver studies, or modeling of stent vessel interaction) for the chosen durability bench tests. Additional conditions that may be considered include vessel calcification, vessel taper, eccentric lesions, deformation excursions (e.g., exer...
SCOPE
1.1 This guide includes three separate cyclic deformation durability guides related to vascular stents: bending, axial, and torsional.  
1.2 This guide does not address flat plate, local crush durability, or multi-mode testing.  
1.3 This guide applies to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents (i.e., stent with a surface layer of an additional material(s)), monolithically polymeric stents, or absorbable stents, although the application of this standard to those products is not precluded.  
1.4 This guide is applicable to testing of stent(s) (or a representative portion of a stent). While durability testing of coupon samples (e.g., a scaled-up portion of the stent structure) can provide useful information, it is not within the scope of this guide.  
1.5 This guide applies to endovascular grafts (“stent-grafts”) and other conduit products commonly used to treat aneurismal disease, peripheral vessel trauma, or to provide vascular access. The information provided herein does not address all issues related to testing of these devices.  
1.6 This guide applies to in vitro modeling of stent durability from non-radial arterial motions. Such motions may arise from musculoskeletal activities, including walking and breathing, and cardiac motion. ASTM F2477 addresses pulsatile (i.e., radial) durability of vascular stents.  
1.7 This guide does not provide the in vivo physiologic deformation conditions for a vascular stent. It is incumbent upon the user of the standard to develop and justify these boundary conditions (e.g., literature review, in vivo studies, cadaver studies, or modeling of stent vessel interaction) in these durability bench tests. Additional conditions that may be considered include vessel calcification, vessel taper, eccentric lesions, loading excursions (e.g., exercise), and vessel remodelin...

SIGNIFICANCE AND USE
4.1 Vascular stents are intended for permanent implant in the human vasculature (native or graft) for the purposes of maintaining vessel patency. The dimensional attributes of vascular stents are critical parameters that aid clinicians in the selection of devices for individual patients. This guide contains a listing of those dimensional attributes that are directly related to the clinical utility and performance of these devices, along with recommendations for consistent methods of measuring these attributes and presenting the information for use in clinical decision making. This guide can be used by the manufacturers and researchers of stents to provide consistency of measurement and labeling of these dimensional characteristics. It may have use in the regulation of these devices by appropriate authorities.  
4.2 The dimensional attributes included in this guide are those that are deemed related to or possibly predictive of successful clinical performance of the stent, based on prior clinical experience; however, because of the myriad patient and medical factors that influence the clinical outcome of any individual treatment, conformance of a stent and delivery system with the recommendations in this guide should not be interpreted as a guarantee of clinical success in any individual patient or group of patients.
SCOPE
1.1 This guide covers the identification of and recommended measurement methods for those dimensional attributes of vascular stents that are deemed relevant to successful clinical performance. The delivery system packaged with and labeled specifically for use during the placement of the stent is also included within the scope of this guide.  
1.2 This guide addresses only the  dimensional characteristics of stents. Material property and stent functional characteristics are not addressed herein. All dimensional characteristics described in this guide refer to in vitro (“bench-top”) characterization. Because of variable patient factors, for example, vessel compliance, the actual in vivo characteristics may be slightly different.  
1.3 This guide includes recommendations generally applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents or polymeric or biodegradable stents, although the application of this guide to those products is not precluded.  
1.4 While they are not specifically included within the scope of this guide, stents indicated for placement in nonvascular locations, such as the esophagus or bile duct, also might be characterized by the methods contained herein. Likewise, this guide does not include recommendations for endovascular grafts (“stent-grafts”) or other conduit devices commonly used to treat aneurysmal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.  
1.5 This guide does not include recommendations for balloon catheters sold as stand-alone angioplasty catheters, even though some of those catheters may be used for the delivery of unmounted stents supplied without a delivery system. Requirements for angioplasty catheters are contained in standards ISO 10555-1 and ISO 10555-4.  
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.6.1 The units of measurements used throughout this guide reflect the hybrid system in common clinical use in the United States as of the time of the original approval of this guide. Since a primary purpose of this guide is to promote uniformity of labeling to facilitate the selection of devices by clinical users, the units most preferred by users w...

SIGNIFICANCE AND USE
5.1 The test results are substantially affected by donor species and age, the method of harvesting, the period of storage, the biochemical state of the blood, and the hemoglobin and hematocrit level of blood.3,4 Therefore, standardization of proper blood usage for in vitro evaluation of blood pumps is essential, and this recommended practice will allow a universal comparison of test results.  
5.2 Drawing several units of blood from healthy cattle does not affect them or their health. Therefore, bovine blood is strongly suggested for usage in experimental evaluation of blood damage. Mixing two donor sources of blood should be avoided in hemolysis tests because the mixture may induce added hemolysis or a change in red cell resistance against trauma.
SCOPE
1.1 This practice covers blood that will be used for  in vitro performance assessments of blood pumps. These assessments include the hemolytic properties of the devices.  
1.2 This practice covers the utilization of blood for the in vitro evaluation of the following devices:  
1.2.1 Continuous flow rotary blood pumps (roller pumps, centrifugal pumps, axial flow pumps, and so forth) (see Practice F1841).  
1.2.2 Pulsatile blood pumps (pneumatically driven, electromechanically driven, and so forth).  
1.3 The source of blood utilized for in vitro evaluation of blood trauma (that is, hemolysis caused by the blood pumps, due to the pump design, construction, and materials used) substantially influences the results of the performance of these devices. Thus, a standardized blood source is required.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

ABSTRACT
This test method covers the procedure for determining the durability of ballon-expandable and self- expanding metal or alloy vascular stents. Tests are performed by exposing specimens to physiologically relevant diametric distention levels using hydrodynamic pulsatile loading. Specimens should have been deployed into a mock or elastically simulated vessel prior to testing. The test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distention and include physiological pressure tests and diameter control tests. These do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion. Test apparatus include a pressure measurement system, dimensional measurement devices, a cycle counting system, and a temperature control system.
SCOPE
1.1 These test methods cover the determination of the durability of a vascular stent by exposing it to physiologically relevant diametric distension levels by means of hydrodynamic pulsatile loading. This testing occurs on a stent test specimen that has been deployed into a mock (elastically simulated) vessel. The typical duration of this test is 10 years of equivalent use (at 72 beats per minute), or at least 380 million cycles.  
1.2 These test methods are applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this test method to those products is not precluded.  
1.3 These test methods do not include recommendations for endovascular grafts (“stent-grafts”) or other conduit products commonly used to treat aneurismal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.  
1.4 These test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distension. These test methods do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion.  
1.5 These test methods do not address test conditions for curved mock vessels.  
1.6 These test methods do not address test conditions for overlapping stents.  
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.9 General Caveat—This document contains guidance for testing as is currently carried out in most laboratories. Other testing techniques may prove to be more effective and are encouraged. Whichever technique is used, it is incumbent upon the tester to justify the use of the particular technique, instrument, and protocol. This includes the choice of and proper calibration of all measuring devices. Deviations from any of the suggestions in this document may be appropriate but may require the same level of comprehensive justification that the techniques described herein will require.

SIGNIFICANCE AND USE
6.1 The objective of this practice is to standardize the evaluation method for detecting the hemolytic effect of a continuous flow blood pump used in extracorporeal circulation and circulatory assistance.
SCOPE
1.1 This practice covers a protocol for the assessment of the hemolytic properties of continuous flow blood pumps used in extracorporeal or implantable circulatory assist. An assessment is made based on the pump's effects on the erythrocytes over a certain period of time. For this assessment, a recirculation test is performed with a pump for 6 h.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 Minimal stent recoil is a desirable feature of a stent because it minimizes the maximum diameter to which a stent must be expanded to achieve its final relaxed diameter. A stent having a high recoil must be expanded to a greater diameter to achieve its final relaxed diameter than a stent having low recoil. Practically, excessive expansion of the vessel into which the stent is to be implanted may cause tissue damage resulting in a poor immediate result or poor long-term outcome. Stent recoil is affected by intrinsic properties of the material used to construct the stent and the specific geometric design of the stent; therefore, measuring stent recoil is an essential part of evaluating the design.
SCOPE
1.1 The purpose of this test method is to quantify the percentage by which the diameter of a stent decreases from its expanded diameter while still on the delivery balloon to its relaxed diameter after deflating the balloon. This test method is appropriate for stents manufactured from a material that is plastically deformed when the stent's diameter is increased from its predeployed size to its postdeployed size by mechanical means. This test method may be performed in air at room temperature unless there is a known temperature dependence of the material, in which case, the temperature at which the test is conducted shall be stated in the report.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The securement of the endovascular stent on the balloon is a critical parameter to ensure that the stent is safely delivered to or from the treatment site.  
4.2 This guide is intended for use by researchers and manufacturers for the development and selection of pre-test treatments, tests and test endpoints to measure stent securement (displacement distances and dislodgment forces).  
4.3 This guide may be used to investigate which practical combinations of in vitro tests best characterize clinical scenarios.  
4.4 This guide should be used with discretion in choosing securement tests and evaluating results due to the myriad possible combinations of clinical conditions, failure modes, and stent delivery system designs.  
4.5 This guide may be of use for developing a test for meeting 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 meet section VII-C-8 of CDRH Guidance document.
SCOPE
1.1 This guide provides guidance for the design and development of pre-test treatments, tests, and test endpoints to measure stent securement of pre-mounted, unsheathed, balloon-expandable stent delivery systems. This guide is intended to aid investigators in the design, development, and in vitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.  
1.2 This guide covers the laboratory determination of the shear 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 testing stent securement. The options cover pre-test treatments, possible stent securement tests, and relevant test endpoints. An example test apparatus is given in 7.1.  
1.3 This guide covers in vitro bench testing characterization only. Measured levels of securement and product design/process differentiation may be particularly influenced by selections of pre-test treatments, securement test type (for example, stent gripping method), and test endpoint. In vivo characteristics may also differ from in vitro results.  
1.4 This guide does not cover all possible pre-test treatments, stent securement tests, or test endpoints. It is intended to provide a starting point from which to select and investigate securement test options.  
1.5 This guide does not specify a method for mounting the stent onto the delivery system.  
1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

SIGNIFICANCE AND USE
The purpose of this guide is to provide a procedure for determining the appropriate attributes to evaluate in a shelf-life study for an endovascular device.
SCOPE
1.1 This guide addresses the determination of appropriate device attributes for testing as part of a shelf-life study for endovascular devices. Combination and biodegradable devices (for example drug-devices, biologic devices or drug biologics) may require additional considerations, depending on their nature.  
1.2 This guide does not directly provide any test methods for conducting shelf-life testing.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
The shedding of the coating from a vascular stent can alter its clinical safety and/or therapeutic benefit. Clinical performance (for example, drug elution) may be affected by particulate generation from the coated stent system and coating defects. This document provides guidance for coating inspection and acute particulate characterization of drug eluting vascular stents. Information about the potential for shedding can be gained during bench testing. The general guidelines presented here may be used for writing detailed protocols for specific products at the various stages of the product development process. Such testing may be performed during device development, design validation testing, lot-release testing, and/or stability testing although different requirements may apply at each stage. These suggested methods may represent a reasonable simulation of clinical usage. When establishing the coating inspection and acute particulate characterization testing conditions, the current clinical usage/practice (for example, post-dilation, overlapping stents) and the instructions for use (IFU), as applicable, should be considered. While methods for chronic particulate characterization and coating inspection have not been established, these suggested methods may be helpful in the development of chronic methods. Testing in accordance with recommendations in this guide will generate data that may lead to further improvements in the method and its validation, as well as possible advancements in device design and performance. See also FDA Guidance for Industry and FDA Staff and AAMI TIR42:2010.
SCOPE
1.1 This guide describes recommended in vitro test procedures for coating inspection and acute particulate characterization of coated drug-eluting vascular (balloon-expandable and self-expanding) stent systems.
1.2 Recommended practices for coating inspection and acute particulate characterization include baseline (deployment) testing and simulated use testing. This guide describes the capture and analysis of particulates. This guide describes the inspection of the coated stent surface. This guide was developed for characterization and not intended for production release testing of coated drug-eluting vascular stent systems although some sections may be appropriate.
1.3 Chronic particulate characterization and coating inspection are not included herein.
1.4 Coating systems specifically designed to degrade or otherwise intentionally separate themselves from the permanent stent structure may not be fully addressed herein.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

SIGNIFICANCE AND USE
Minimal stent recoil is a desirable feature of a stent because it minimizes the maximum diameter to which a stent must be expanded to achieve its final relaxed diameter. A stent having a high recoil must be expanded to a greater diameter to achieve its final relaxed diameter than a stent having low recoil. Practically, excessive expansion of the vessel into which the stent is to be implanted may cause tissue damage resulting in a poor immediate result or poor long-term outcome. Stent recoil is affected by intrinsic properties of the material used to construct the stent and the specific geometric design of the stent; therefore, measuring stent recoil is an essential part of evaluating the design.
SCOPE
1.1 The purpose of this test method is to quantify the percentage by which the diameter of a stent decreases from its expanded diameter while still on the delivery balloon to its relaxed diameter after deflating the balloon. This test method is appropriate for stents manufactured from a material that is plastically deformed when the stent's diameter is increased from its predeployed size to its postdeployed size by mechanical means. This test method may be performed in air at room temperature unless there is a known temperature dependence of the material, in which case, the temperature at which the test is conducted shall be stated in the report.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
This guide can be used to obtain force versus deflection or midspan bending moment versus midspan curvature curves for stents and stent systems subjected to three-point bending conditions. Bending flexibility of a stent system may be a factor in its ability to track through the vascular anatomy, and may be a factor in vascular trauma along the delivery pathway distal to the guide catheter. Bending flexibility of a deployed stent may be one measure of its ability to flex with a vessel, or to conform to the natural curvature of a vessel. Bending flexibility of a delivery system may also be of interest if it is desired to assess the separate contributions of the delivery system and the mounted stent to the overall flexibility of the stent system.
This guide is not intended to determine material properties, stent system trackability (ability of a stent system to follow a guide wire and/or guide catheter through vascular tortuosity), or stent system deliverability (ability of a stent system to deliver a stent to the implantation site(s) or through particular level(s) of vascular tortuosity). While this guide does not determine stent system trackability or deliverability, it can provide quantitative insight into how stent system bending flexibility affects trackability and deliverability. Similarly, while this guide does not determine conformability of a deployed stent, it can provide quantitative insight into how stent and/or stent system bending flexibility affects deployed stent conformability. Since this guide quantifies bending flexibility, it may be useful in determining the magnitude of bending flexibility effects on bending-related performance differences between the test article and control devices.
The three-point bending procedures provided in this guide are intended to be used to characterize balloon-expandable stent and stent system flexibility during product development. They may not necessarily satisfy any particular requirements of national or internat...
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1.1 This guide provides guidelines for quantitatively characterizing balloon-expandable stent and stent system flexibility using three-point bending procedures. Guidelines are provided for characterizing deployed stent flexibility, and for characterizing pre-deployment stent system flexibility in the region of the stent and balloon.
1.2 This guide is not recommended for test articles that cannot be appropriately evaluated using a span length to stent outer diameter (as tested) ratio of at least 4:1. Test articles that do not meet this requirement are likely to exhibit appreciable deformation by modes other than bending.
1.3 This guide does not provide procedures for characterizing the bending flexibility of self-expanding stents, self-expanding stent systems, endoprostheses (stent-grafts), or endoprostheses systems. However, some aspects of this guide may be useful for developing appropriate three-point bending characterization procedures for these devices. While this guide was developed with vascular stents and stent systems in mind, it may be useful for characterizing the bending flexibility of balloon-expandable stents and stent systems used in non-vascular applications.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.

SIGNIFICANCE AND USE
Finite element analysis is a valuable method for evaluating the performance of metallic stents and in quantifying quantities such as internal stresses, internal strains, and deformation patterns due to applied external loads and boundary conditions. Many times an analysis is performed to correlate to and plan experimental tests. A finite element analysis is especially valuable in determining quantities that cannot be readily measured.
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1.1 Purpose—This guide establishes general requirements and considerations for the development of finite element models used in the evaluation of the performance of a metallic vascular stent design under uniform radial loading. Suggested criteria are provided for evaluating the typical cases of metallic stents under uniform radially oriented and pulsatile loading. Recommended procedures for checking and validating the finite element model(s) are provided as a means to assess the model and analysis results. Finally, the recommended content of an engineering report covering the mechanical simulations is presented.
1.2 Limits:
1.2.1 This guide is limited in discussion to the finite element structural analysis of metallic stents of the following types:
1.2.1.1 Plastically deformable metal stents.
1.2.1.2 Self-expanding metal stents.  
1.2.1.3 Plastically deformable metal portions of covered stents.
1.2.1.4 Metal portions of self-expanding covered metal stents.  
1.2.2 The emphasis of the techniques described in this guide is intended for both elasto-plastic materials such as stainless steel, and superelastic materials such as nitinol. Unique concerns associated with stents designed for shape memory behavior are not addressed within this guide.  
1.2.3 This guide does not consider changes to possible time varying conditions or different loadings related to vascular remodeling.  
1.2.4 This guide is restricted to cases that involve the application of uniform radially oriented loading.
1.2.5 This guide does not provide guidance in the application or interpretation of FEA in determining fatigue life.
1.2.6 This guide is not intended to include complete descriptions of the finite element method, nor its theoretical basis and formulation.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

SIGNIFICANCE AND USE
Minimal stent recoil is a desirable feature of a stent because it minimizes the maximum diameter to which a stent must be expanded to achieve its final relaxed diameter. A stent having a high recoil must be expanded to a greater diameter to achieve its final relaxed diameter than a stent having low recoil. Practically, excessive expansion of the vessel into which the stent is to be implanted may cause tissue damage resulting in a poor immediate result or poor long-term outcome. Stent recoil is affected by intrinsic properties of the material used to construct the stent and the specific geometric design of the stent; therefore, measuring stent recoil is an essential part of evaluating the design.
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1.1 The purpose of this test method is to quantify the percentage by which the diameter of a stent decreases from its expanded diameter while still on the delivery balloon to its relaxed diameter after deflating the balloon. This test method is appropriate for stents manufactured from a material that is plastically deformed when the stent's diameter is increased from its predeployed size to its postdeployed size by mechanical means. This test method may be performed in air at room temperature unless there is a known temperature dependence of the material, in which case, the temperature at which the test is conducted shall be stated in the report.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
The securement of the endovascular stent on the balloon is a critical parameter to ensure that the stent is safely delivered to or from the treatment site.
This guide is intended for use by researchers and manufacturers for the development and selection of pre-test treatments, tests and test endpoints to measure stent securement (displacement distances and dislodgment forces).
This guide may be used to investigate which practical combinations of in vitro tests best characterize clinical scenarios.
This guide should be used with discretion in choosing securement tests and evaluating results due to the myriad possible combinations of clinical conditions, failure modes, and stent delivery system designs.
This guide may be of use for developing a test for meeting parts 2 and 3 of the requirements of EN 14299, Section 7.3.4.4 on Trackability.
This guide may be of use for developing a test to meet section VII-C-8 of CDRH Guidance document.
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1.1 This guide provides guidance for the design and development of pre-test treatments, tests, and test endpoints to measure stent securement of pre-mounted, unsheathed, balloon-expandable stent delivery systems. This guide is intended to aid investigators in the design, development, and in vitro characterization of pre-mounted, unsheathed, balloon-expandable stent delivery systems.
1.2 This guide covers the laboratory determination of the shear 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 testing stent securement. The options cover pre-test treatments, possible stent securement tests, and relevant test endpoints. An example test apparatus is given in .
1.3 This guide covers in vitro bench testing characterization only. Measured levels of securement and product design/process differentiation may be particularly influenced by selections of pre-test treatments, securement test type (for example, stent gripping method), and test endpoint. In vivo characteristics may also differ from in vitro results.
1.4 This guide does not cover all possible pre-test treatments, stent securement tests, or test endpoints. It is intended to provide a starting point from which to select and investigate securement test options.
1.5 This guide does not specify a method for mounting the stent onto the delivery system.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

ABSTRACT
This test method covers the procedure for determining the durability of ballon-expandable and self- expanding metal or alloy vascular stents. Tests are performed by exposing specimens to physiologically relevant diametric distention levels using hydrodynamic pulsatile loading. Specimens should have been deployed into a mock or elastically simulated vessel prior to testing. The test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distention and include physiological pressure tests and diameter control tests. These do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion. Test apparatus include a pressure measurement system, dimensional measurement devices, a cycle counting system, and a temperature control system.
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1.1 These test methods cover the determination of the durability of a vascular stent by exposing it to physiologically relevant diametric distension levels by means of hydrodynamic pulsatile loading. This testing occurs on a stent test specimen that has been deployed into a mock (elastically simulated) vessel. The typical duration of this test is 10 years of equivalent use (at 72 beats per minute), or at least 380 million cycles.
1.2 These test methods are applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this test method to those products is not precluded.
1.3 These test methods do not include recommendations for endovascular grafts ("stent-grafts") or other conduit products commonly used to treat aneurismal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.
1.4 These test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distension. These test methods do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion.
1.5 These test methods do not address test conditions for curved mock vessels.
1.6 These test methods do not address test conditions for overlapping stents.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.8 General Caveat—This document contains guidance for testing as is currently carried out in most laboratories. Other testing techniques may prove to be more effective and are encouraged. Whichever technique is used, it is incumbent upon the tester to justify the use of the particular technique, instrument, and protocol. This includes the choice of and proper calibration of all measuring devices. Deviations from any of the suggestions in this document may be appropriate but may require the same level of comprehensive justification that the techniques described herein will require.

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1.1 These test methods cover the determination of the durability of a vascular stent by exposing it to physiologically relevant diametric distension levels by means of hydrodynamic pulsatile loading. This testing occurs on a stent test specimen that has been deployed into a mock (elastically simulated) vessel. The typical duration of this test is 10 years of equivalent use (at 72 beats per minute), or at least 380 million cycles.
1.2 These test methods are applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents, polymeric stents, or biodegradable stents, although the application of this test method to those products is not precluded.
1.3 These test methods do not include recommendations for endovascular grafts ("stent-grafts") or other conduit products commonly used to treat aneurismal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.
1.4 These test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distension. These test methods do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion.
1.5 These test methods do not address test conditions for curved mock vessels.
1.6 These test methods do not address test conditions for overlapping stents.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.7 General Caveat This document contains guidance for testing as is currently carried out in most laboratories. Other testing techniques may prove to be more effective and are encouraged. Whichever technique is used, it is incumbent upon the tester to justify the use of the particular technique, instrument, and protocol. This includes the choice of and proper calibration of all measuring devices. Deviations from any of the suggestions in this document may be appropriate but may require the same level of comprehensive justification that the techniques described herein will require.

SIGNIFICANCE AND USE
Vascular stents are intended for permanent implant in the human vasculature (native or graft) for the purposes of maintaining vessel patency. The dimensional attributes of vascular stents are critical parameters that aid clinicians in the selection of devices for individual patients. This guide contains a listing of those dimensional attributes that are directly related to the clinical utility and performance of these devices, along with recommendations for consistent methods of measuring these attributes and presenting the information for use in clinical decision making. This guide can be used by the manufacturers and researchers of stents to provide consistency of measurement and labeling of these dimensional characteristics. It may have use in the regulation of these devices by appropriate authorities.
The dimensional attributes included in this guide are those that are deemed related to or possibly predictive of successful clinical performance of the stent, based on prior clinical experience; however, because of the myriad patient and medical factors that influence the clinical outcome of any individual treatment, conformance of a stent and delivery system with the recommendations in this guide should not be interpreted as a guarantee of clinical success in any individual patient or group of patients.
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1.1 This guide covers the identification of and recommended measurement methods for those dimensional attributes of vascular stents that are deemed relevant to successful clinical performance. The delivery system packaged with and labeled specifically for use during the placement of the stent is also included within the scope of this guide.
1.2 This guide addresses only the  dimensional characteristics of stents. Material property and stent functional characteristics are not addressed herein. All dimensional characteristics described in this guide refer to in vitro ("bench-top") characterization. Because of variable patient factors, for example, vessel compliance, the actual in vivo characteristics may be slightly different.
1.3 This guide includes recommendations generally applicable to balloon-expandable and self-expanding stents fabricated from metals and metal alloys. It does not specifically address any attributes unique to coated stents or polymeric or biodegradable stents, although the application of this guide to those products is not precluded.
1.4 While they are not specifically included within the scope of this guide, stents indicated for placement in nonvascular locations, such as the esophagus or bile duct, also might be characterized by the methods contained herein. Likewise, this guide does not include recommendations for endovascular grafts ("stent-grafts") or other conduit devices commonly used to treat aneurysmal disease or peripheral vessel trauma or to provide vascular access, although some information included herein may be applicable to those devices.
1.5 This guide does not include recommendations for balloon catheters sold as stand-alone angioplasty catheters, even though some of those catheters may be used for the delivery of unmounted stents supplied without a delivery system. Requirements for angioplasty catheters are contained in standards ISO 10555-1 and ISO 10555-4.
1.6 The units of measurements used throughout this guide reflect the hybrid system in common clinical use in the United States as of the time of the original approval of this guide. Since a primary purpose of this guide is to promote uniformity of labeling to facilitate the selection of devices by clinical users, the units most preferred by users were selected for this guide. Where those units are not SI units, or derivatives thereof, SI units are provided in parentheses.

SIGNIFICANCE AND USE
The objective of this practice is to standardize the evaluation method for detecting the hemolytic effect of a continuous flow blood pump used in extracorporeal circulation and circulatory assistance.
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1.1 This recommended practice covers a protocol for the assessment of the hemolytic properties of continuous flow blood pumps used in extracorporeal or implantable circulatory assist. An assessment is made based on the pump's effects on the erythrocytes over a certain period of time. For this assessment, a recirculation test is performed with a pump for 6h.  
1.2 The values stated in both inch-pound and SI units are to be regarded as the standard. The SI units given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.