ASTM F2477:19 pdf download

ASTM F2477:2019 pdf download.Standard Test Methods for in vitro Pulsatile Durability Testing of Vascular Stents.
7. General Test Parameters
7. 1 Temperature—The temperature shall be 37 ± 2°C. If other temperatures are to be used, a rationale shall be provided stating why the particular temperature is considered worst case or equivalent. The unit is to be stable over the intended period of the test and maintained within the established parameters.
7.2 Actual temperatures and precisions shall he documented by the user with accompanying justifications.
7.3 Solutions—The test solution shall be phosphate buffered saline (PBS) or equivalent unless testing in a different environment (such as in distilled water or in air) can be justified. Rationale for use of a different environment shall he provided.
7.4 Physiological Pressure—The pressure change in the intended blood vessel. A suggested range for coronary stent pulsatile fatigue evaluation is 0 to 160 mm Hg.
NOTE 1—Selection of the systolic and diastolic pressures should be based on the patient population for which the stent is indicated.
7.5 Physiological Pulse Rate—For the purposes of these test methods, determined to be 1 .2 Hz or 72 beats per minute.
7.6 Biological growth can inhibit post-test evaluation of the stent surface characteristics. Use of a biological growth inhibitor (such as algaecides or chemical agents) may be used unless such use would negatively impact the test by unintended degradation of the stent or the test set-up.
7.7 The ID of the non-stented mock vessel is to be empirically verified on the test instrument after the mock vessel(s) have been mounted in their initial test position.
7.8 Vessel Degradation—Mock vessels made of materials that may degrade with exposure to environmental factors (such as UV light) shall be protected from such exposure.
7.9 Stem Deployment—The stent shall be deployed in the mock vessel in such a manner as to minimize end effects where the vessel is connected to the test article and at a sufficient distance from other stents that may be deployed in the same vessel (see X2.5).
7.10 Test Frequency—See Annex Al and Annex A2 for test specific details.
7. 11 Test Validation—The investigator shall demonstrate that the stent to be tested maintains contact with the ID of the vessel to be used in the durability test throughout the cycle, when evaluated with the same pressures and frequencies to be used in the durability test. This is not required for every sample. This and any justifications shall be documented in the test report. Rationale: The functionality of a test method used to test a stent inside a vessel depends on the stent remaining in contact with the ID of the vessel throughout the distension cycle of that vessel.
7. 1 2 Acceptance Criteria—A detailed test protocol shall he written that describes all procedures unique to the stent being evaluated. This protocol shall include any specific failure modes to be identified, and inspections to be performed to identify those failures in any acceptance/rejection criteria. (See Appendix for examples.)