DEFORMATION CHARACTERISTICS OF A BIOABSORBABLE INTRAVASCULAR STENT

RATIONALE AND OBJECTIVES. Biodegradable polymeric stents offer an alternative to metallic stents, which have a significant compliance mismatch with blood vessels and have the potential for long-term complications. In the current study, the deformation characteristics of polymeric stents have been investigated. METHODS. Stents were subjected to radial compressive pressure by inserting them in a wrap-around collar, one end of which was loaded in tension using dead-weights. The resulting decrease in stent diameter was measured under an optical microscope. Deformation curves for the stents were plotted, and an effective stiffness, E', was determined for each. RESULTS. The deformation curves exhibited two different regions: an initial linear region, followed by a steep nonlinear region. The transition from the linear region occurred at a fractional decrease in stent diameter of approximately 0.5. CONCLUSION. E' decreases with increasing stent diameter and filament draw-ratio. The relationship between E' and the initial stent diameter is not linear. The deformation curves can be used for choosing the appropriate stents for specific applications.