How do I know the stent actually follows the inside motion of the mock artery?
This is an excellent question and is core to all the new stent fatigue/durability guidances and standards generated by the FDA, ASTM, and ISO. The typical radial resonant frequency for most stents and stented grafts is much higher (several hundred Hz) than the frequency the durability tests. The stent may be modeled as a spring placed in parallel with the mock artery. Using this model, the stent always maintains contact with the mock artery wall. The new regulatory guidance and standards require that the testing lab verify that a sample of the device to be tested follows the ID of the mock artery at the diametric distention levels and frequencies to be used. This is true no matter which test method used. In the past Bose ESG had used an endoscope, video camera and strobe to verify the motion of the mock artery inner lumen and stent. Our customers often have better methods to view and verify the motion of the stent inside the mock artery for this validation.
