ASTM F2477 | Vascular Stents | Fatigue Testing
ASTM F2477 describes physiological pressure and diameter-control test methods to evaluate the dynamic-fatigue mechanical behavior of balloon-expandable and self-expanding metallic vascular stents. These tests are performed under in-vivo simulated conditions so that medical device manufacturers can assess the durability of these specific vascular stents as surrounding blood vessels expand and contract.
This test standard outlines dynamic cyclic test methods that evaluate the durability of vascular stents over their 10-year life expectancy, based on the normal pulse rate in humans. The resulting data can be used to support regulatory submissions.
The outlined physiological pressure test method utilizes stents and mock blood vessels so that manufacturers can evaluate the dynamic-fatigue behavior of these specific vascular stents via a load-control test until the specific cycle count (at least 380 million cycles) or functional failure is obtained.
The outlined diameter control test method utilizes a diameter measurement system, vascular stents, and mock blood vessels that enable manufacturers to evaluate the dynamic-fatigue behavior of these specific vascular stents via a strain-control test until the specific cycle count (at least 380 million cycles) or functional failure is obtained.
Before conducting ASTM F2477, it is important to read the entire specification in the relevant ASTM publication.
Click here to read our blog post on Mechanical Testing of Vascular Stents.
ASTM F2477 | Vascular Stents | Fatigue Testing
Physiological Pressure Test Method
- Follow the apparatus requirements for load-control testing.
- Position the stent into the mock vessel according to the device’s instructions.
- Inspect stent and record location of any irregularities.
- Install the mock vessel/stent combination into the fatigue/durability test system.
- Start the test system and adjust frequency and cyclic pressure to target levels.
- Perform desired load-controlled test method until the specified cycle count has been obtained to evaluate dynamic-fatigue behavior.
Diameter Control Test Method
- Regulate the maximum and minimum diameters the stent would experience in vivo.
- Insert the appropriate mock vessel into the fatigue test system, and fill the system with solution.
- Position the stent into the mock vessel.
- Examine stent and record location and any irregularities.
- Record the position and distance of each stent in the mock vessel in the fatigue/durability system.
- Start the test system.
- Continue the desired strain-controlled test method until the required number of cycles is achieved to evaluate dynamic-fatigue behavior.
- Cycles to Failure
ASTM F2477 | Vascular Stents | Fatigue Testing
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