Information on the most widely used ASTM standards within the materials testing industry
ISO/TS 17137:2021 Cardiovascular implants and extracorporeal systems — Cardiovascular absorbable implants
Based on the ISO/TS 17137 standard the evaluation of mechanical properties is a critical part of the design and safety validation process. Mechanical Evaluation like tension, radial force, Cyclic Fatigue Durability like constant pulsing. Because absorbable implants lose their structural integrity over time through degradation, their mechanical performance must be assessed not just at the time of implantation, but throughout their intended functional lifetime.
Core Mechanical Tests stipulated:
| 1, Mechanical Evaluation Test | |
| Key test | Radial force (stents); Crush resistance; Tensile/bending performance; Structural integrity (no strut fracture, coating delamination, premature degradation) |
| Test Requirement | Test under physiologically relevant conditions: 37 °C, fully immersed in simulated body fluid; written justification is mandatory if tested under dry/room-temperature conditions. Follow device-specific standards: ISO 25539 series (endovascular devices) & ISO 5840 series (cardiac valve prostheses). Test time points cover the intermediate degradation stage (from post-deployment to undetectable mechanical attributes); advanced-stage testing is not performed (mechanical properties below detection limit). Characterize the temporary initial rise in mechanical properties (strength, rigidity) after implantation (caused by hydration, thermal equilibration for polymers/metals). |
| Test Equipment | Universal mechanical tester, Radial force tester, Three-point bending tester or Test fixtures (ASTM F2606) |
| Test Samples | Final sterilized finished devices (consistent with clinical specifications). Pre-conditioned to simulate clinical use: unpacking, preparation per IFU, simulated vascular tracking/deployment. Parallel samples tested at multiple degradation time points. |
| Importance | Verify initial mechanical function meets clinical requirements after deployment. Clarify mechanical property decay during degradation to ensure performance within the designed functional lifetime. Prevent early mechanical failure (stent collapse, fracture) leading to thrombosis/embolism. |
| Application for | Absorbable coronary/peripheral stents, vascular closure devices, heart valves, vena cava filters. Evaluate material selection, structural design, and manufacturing rationality. |
| 2, Cyclic Fatigue Durability Test | |
| Key Test | Radial Durability, Axial Durability, Bending Durability, Torsional loading Durability Test |
| Test requirement | Test duration covers the expected functional lifetime (limited to the intermediate stage). Conduct under physiological temperature/fluid environment; hyper-physiological loading can be used to analyze failure mechanisms. Accelerated testing: synchronize chemical degradation rate with accelerated loading rate (via temperature elevation, pH adjustment); justification required if not synchronized. Refer to ASTM F3211; for absorbable metals, in vitro tests can be supplemented/replaced by in vivo preclinical studies (tissue coverage provides mechanical support in vivo). |
| Test Equipment | Cyclic fatigue tester (pulsatile, axial, bending fatigue load). Vascular Stent Radial Pulsatile Fatigue Testing System Vascular Stent Uniaxial Tension Durability Testing Machine. |
| Test Samples | Sterilized finished products (clinical size/design). Pre-conditioned by simulated use. Multiple sample groups for different cycle numbers/degradation time points. |
| Importance | Evaluate long-term structural durability under cyclic loading to avoid fatigue fracture, particulate generation, or late adverse events. Confirm the matching of fatigue life and degradation cycle to ensure safety throughout the functional period. |
| Application | Implants under dynamic cyclic load (coronary stents, heart valve implants, vena cava filters). |
Core purpose of ISO 17137
To establish full-lifecycle requirements for absorbable cardiovascular implants, covering design, fabrication, packaging, sterilization, shelf-life, risk management, and in vitro / preclinical / clinical evaluation. It targets the unique hazards of absorbable materials (premature degradation, particulate generation, fracture, late adverse events) to ensure clinical safety and performance.
Related products and device
Related Standard
ISO 7198 specifies test and performance requirements for tubular vascular grafts and vascular patches (surgical vascular prostheses). It defines mechanical tests (with full method/equipment/sample details) and other physicochemical, biological, dimensional, preclinical/clinical tests.
ISO 12417-1 specifies requirements for Vascular Device-Drug Combination Products (VDDCPs) (drug-eluting stents, drug-coated balloons, drug-bearing vascular grafts, etc.). It mandates mechanical tests for the device part (DP) (to verify structural/functional integrity) and a suite of drug-related, physicochemical, biological, and clinical tests. Mechanical performance must comply with device-specific standards (ISO 25539-2, ISO 10555-4, ISO 7198) and remain unaffected by the drug-containing part (DCP).
ASTM F3067 establishes in vitro test frameworks to characterize the radial mechanical performance of balloon-expandable vascular stents and self-expanding vascular stents. It quantifies three key indicators: radial strength and collapse pressure for balloon-expandable stents, and chronic outward force (COF) for self-expanding stents.
ASTM F2942 specifies in vitro test methodologies to evaluate the cyclic durability of vascular stents under non-radial mechanical deformations (axial, bending, and torsion) that occur in vivo due to musculoskeletal motion, breathing, or cardiac activity. include Axial, bending, torsional, Pulsatile Durability, Radial Loading etc., test.
ASTM F2606 defines quantitative three-point bending procedures to characterize the bending flexibility and stiffness of balloon-expandable vascular stents and stent systems (pre-deployment and deployed states). It is a critical testing protocol in the biomedical engineering field. Since vascular anatomies are naturally curved and tortuous, a stent must be flexible enough to navigate through the delivery pathway (trackability) and conform to the vessel's curvature once deployed without causing vascular trauma . This standard provides the guidelines to measure these mechanical properties accurately.
ASTM F2942 specifies in vitro test methodologies to evaluate the cyclic durability of vascular stents under non-radial mechanical deformations (axial, bending, and torsion) that occur in vivo due to musculoskeletal motion, breathing, or cardiac activity.
ASTM F2477 designed to evaluate the long-term fatigue durability and radial cyclic deformation resistance of vascular implants under simulated physiological pulsatile loading conditions. It is crucial for simulating the cyclical stresses these medical devices endure inside human blood vessels.
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