Presentations at the annual Cleveland Clinic Stent Summit, held August 24th-26th, provide new insight into potential failure modes for stents and stent-grafts, and help to reinforce the direction that we have been going with in vitro testing capabilities.
Traditional accelerated fatigue testing for stents and stent-grafts has included radial fatigue testing requirements that replicated ten years of in vivo time. Most of this testing has been performed in idealized mock vessels that don't necessarily replicate the configuration of the diseased vessels. New evidence suggests that fluid dynamics and non-radial loading may be more culpable than radial stress in device failures.
We have developed testing that integrates more clinically relevant vessel designs in testers that better replicate the fluid dynamics thought to cause many of the aortic stent-graft failures. This off-axis, unidirectional flow testing provides a higher degree of confidence in the durability of aortic stent-grafts.
We have also developed, and continue to develop testers that replicate the non-radial motion of arteries into which stents are deployed. To date, we have performed this non-radial fatigue testing for carotid artery and renal artery stents. The carotid artery tester is designed to replicate the bending motion of the carotid during head turning, and the renal artery tester replicates the bending of the renal artery during respiration.
As more information on device failure modes becomes available, we will continue to respond with more representative testing that is better able to predict clinical outcomes.
To learn more about off-axis testing, or to determine if off-axis testing is relevant to your device, contact us by phone at 1.800.325.8252, email us at testing@dynatekdalta.com, or complete our Contact Us form.
