Stent Fatigue Tester
Stent Fatigue Tester
Stent Fatigue Tester

Stent Fatigue Testing: Measured parameters

  • Strain: Direct periodic strain measurement performed with ultrasonic (US) dynamic diameter measuring system
  • Struts and Diameter integrity – Periodic visual inspection and final SEM inspection
  • Cyclic system pressure difference
  • N° of Cycles
  • Test Frequency

Stent Fatigue Testing: Scope

  • Accelerate Fatigue Testing – Coronary and peripheral stent
  • Accelerate Fatigue Testing – Aortic, Thoracic and Heart Valves Stent
  • Accelerate Fatigue Testing – CrCo, SS, NiTi, Bioresorbable, Bioabsorbable, Covered, Coated stent

Stent Fatigue Testing: Applicable standards

Stent Fatigue Testing: Associated tests

Stent Fatigue Testing: Test method description

ProtomedLabs’ proprietary thin tube fatigue tester design does not require deriving any specific tube compliance relationship between tube OD and ID. Up to 21 stents can tested simultaneously in one machine. Stent are positioned in transparent silicon tubes with thin walls.  Tubes are filled with relevant test solutions depending on stent type and test requirements. A cyclic or a static differential pressure can be directly applied on the silicone tubes.

The differential pressure generates a uniform periodic stress of physiologic magnitude at frequencies of up to 60 Hz. Standard tester operating mode can generate operating stress levels with max peripheral pressure difference of 40 mmhg and 0 mmhg minimal pressure. Standard tests are performed with distilled water and under thermo regulated 37+2 °c conditions if required.  Other test fluid can be used for biological tissue covered and biodegradable stent designs.

Stent dynamic displacement is directly measured in-line by ultrasound (us) system in compliance with standard requirement and in order to ensure that dynamic amplitude levels are meeting specifications limits. Applied pressure difference, test frequency, number of cycles and stent positions within the mock artery models are monitored daily. A visual inspection is also performed daily to detect visible stent failure.

Dynamic stent diameters and displacement are measured directly on the device at periodical intervals and at both the beginning and the end of the test.  In order to detect early onset of failure and fracture, periodical diameter and displacement monitoring and measurement can be performed to assess stent behavior. Stent  preparation, cycle counting, test frequency measurements, calibration of the pressure transducers are performed in compliance with and controlled by proper operating procedures.