Coronary artery stents microfabricated from planar metal foil: design, fabrication, and mechanical testing

This paper presents a new approach to the design and manufacture of coronary artery stents, which permits the use of planar batch fabrication technologies. Stent samples with different wall patterns have been fabricated from 50-μm thick stainless steel foil using micro-electro-discharge machining, and expanded to tubular shapes by using angioplasty balloons. The stents exhibit diameter variations of <±4 %, almost zero radial recoil after deflation of the balloon, and longitudinal shrinkage of <3 % upon expansion. Loading tests reveal that the radial strengths match commercially available stents which have twice the wall thickness, while longitudinal compliance, at 0.02 m/N for a 4-mm long section of the stent, is >10× higher.