Jf. Dyet et al., Mechanical properties of metallic stents: How do these properties influence the choice of stent for specific lesions?, CARDIO IN R, 23(1), 2000, pp. 47-54
Purpose. To assess selected balloon-expandable and self-expanding stents fo
r radial force, flexibility, radio-opacity, and trackability, and to relate
these physical characteristics to potential indications for placement.
Methods: Force-strain curves were plotted for each stent and the force requ
ired to produce 50% luminal narrowing was recorded. The ability of the sten
t to show elastic recoil following deformation was also noted. Flexibility
was measured by bending the stents against a force transducer and recording
the force required per degree of flexion. Radio-opacity was measured by co
mparing each stent against a standard aluminum step wedge. Trackability was
measured by testing the ability of the stent on its delivery system to tra
ck over angles of 90 degrees and 60 degrees.
Results: The balloon-expandable stents showed greater radial strength and r
adio-opacity but, apart from the AVE Iliac Bridge stent, showed poorer flex
ibility and trackability. The self-expanding stents showed less radial forc
e but were able to re-expand following deformity. They were generally more
flexible and had better trackability but lower radio-opacity.
Conclusion: There is no stent which exhibits all the ideal properties requi
red and therefore the interventionist will need to keep a range of stents a
vailable if all lesions are to be addressed.