A planar approach for manufacturing cardiac stents: design, fabrication, and mechanical evaluation

A new approach that uses planar batch manufacturing technologies is presented for the design and fabrication of coronary artery stents. Stent samples with different wall patterns have been fabricated from 50-μm-thick stainless steel foil using microelectrodischarge machining. Stents have been expanded to tubular shapes by using angioplasty balloons, both inside mock arteries and without external confinement (i.e., free-standing). Free-standing stents exhibit diameter variations of <±4%, almost zero radial recoil after deflation of the balloon, and longitudinal shrinkage of <3% upon expansion. A variation that uses breakable links to provide additional customization in electrical and mechanical properties is also presented. Loading tests reveal that the radial stiffness of some patterns is comparable to that of commercially available stents with greater wall thickness, while bending compliance, at 0.02 m/N for a 4-mm-long section of the stent, is also favorably large.