Performance characteristics of modern self-expanding nitinol stents indicated for SFA

Abstract

Purpose: To evaluate performance characteristics of currently available superficial femoral artery (SFA) stents and stent delivery systems (SDS).

Materials and methods: Six 7 mm/ 80 mm stent systems were included: BIOTRONIK Astron Pulsar (4F), EDWARDS LifeStent Flexstar, ev3 PROTÉGÉ Everflex, CORDIS Smart Control, BARD E-Luminexx, GUIDANT Absolute (all 6F). The SDS were evaluated for profile, flexibility in the stent region, trackability and pushability through a tortuous vessel model and release force during deployment. The stents were evaluated for flexibility, radial force during expansion and compression, and shortening.

Results: The 4F system had a profile of 1.45 mm, and the 6F stent systems had a profile of 1.96 - 2.10 mm. The Astron Pulsar was most flexible (195 Nmm (2)) compared to 334 - 972 Nmm (2) for the 6F systems. The track force of the stiffest system (Flexstar, 0.314N) was higher than that of the Astron Pulsar (0.273N) but lower than that of the other systems (0.387 - 0.579N). The release force was 1.69N (Absolute), 2.05N (Astron Pulsar) up to 13.00N (Flexstar). The radial force for a 6 mm stent diameter during expansion ranged from 3.95N (Absolute) and 3.99N (Astron Pulsar) up to 7.22N (FlexStar) but was higher when compressed.

Conclusion: The 4F system had the best flexibility and trackability. The release force was high in most systems with release handles. The radial force of all tested stents covers a broad range. These results could be helpful to find the best stent for different lesions.