Mixed Mode Delamination of Stent Coatings During Deployment

Recent advances in angioplasty have involved the application of polymer coatings to stent surfaces for purposes of drug delivery in order to prevent a reblockage of the artery due to smooth muscle cell proliferation. This advance has reduced instances of such restenosis from ∼40% for bare metal stents to ∼5% for drug eluting stents, and has yielded a milti-billion dollar per annum market. However, delamination of polymer coatings on commercial stents has recently been reported using SEM analysis [1, 2]. Such delamination results from interface failure due to high interface tractions developed in the region of the stent plastic hinge.