Radial Compliance Of Natural And Mock Arteries: How This Property Defines The Cyclic Loading Of Deployed Vascular Stents

Biomedical Science Instrumentation, 38, pp. 163-172, (2002)

J. C. CONTI, PH.D.

Dynatek Dalta Scientific Instruments, 105 E. Fourth Street, Galena, MO 65656

There has been a disturbing number of unexpected mechanical failures in deployed vascular stents and stent grafts. An analysis of the mechanical properties of mock arteries used to carry out standard durability testing on the aforementioned medical products suggests that some of the problems might be related to a frequency dependent change in the properties of these recipient vessels. This could lead to a lower than expected level of loading and an attendant reduction in severity of testing.

A clear understanding of how a pulsating artery cyclically loads a deployed stent is important before a mock artery can be designed to carry out biologically relevant in vitro durability testing. In addition, knowledge of the time dependent response of both the vessel and the stent/stent graft is critical before any accelerated testing protocol can be properly designed.

This paper will present an analysis of the loading on a stent versus pressure and diameter of the recipient vessel and how this varies with frequency. Actual compliance versus frequency data will be used from silicone mock arteries.