Coating induced corrosion of coronary stents - A comparative study with clinical consequences

NAVARRO, LUCILA; DUFFO, GUSTAVO; LUNA, JULIO; RINTOUL, IGNACIO

Trends in medicine

Open Access Test

Año: 2020

The clinical fails of gold (Au) and carbon (C) coated 316LSS stents have been barely investigated. A comprehensive understanding of these fails may contribute tothe improvement of protocols for the development of better materials and surfaces. This work elucidates the reasons of the clinical fails of Au and C coated 316LSSstents, demonstrates the physical-chemical processes that leaded to these fails, reviews the mistaken line of thought that pushed these technologies to the mostadvanced clinical stages and proposes complementary techniques to the FDA guidances for the early non-clinical engineering tests. Au and C coated 316LSS, bare-metal 316LSS and Co-Cr stents were studied using potentiodynamic scans according to FDA guidance protocols, image analysis and bulk elemental composition.The statistical clinical outcome of the stents was found to correlate with the ions release patterns eluted from their corresponding metallic substrates. In all cases ionsrelease were consequence of post-passive corrosion processes such as pitting corrosion of 316LSS and bulk grain dissolution of Co-Cr alloy. Surprisingly, the stentsoutcome did not correlate with their corresponding corrosion rates. Clinical fails of Au and C coated 316LSS stents are explained in terms of their fails to inhibitthe ions release from their 316LSS substrates. Materials and surface improvements must be oriented to inhibit post-passive corrosion processes of stents substrates.Potentiodynamic scans complemented with image analysis are strongly recommended for the evaluation of pre-clinical engineering tests.