Stent' In Vitro Degradation Rate and Toxic Degradation Products

Abstract

Medical stents are tubes made of a metal or plastic wire mesh. They are inserted into a hollow structure of a body part to keep an anatomic vessel or passageway open. Stents placed in the body can cause toxic effects by releasing metal ions into the body, and can also cause harmful effects on the body by creating corrosion products. In this study, the decomposition rate and release of corrosion products in artificial body fluid (PBS) of a stent sample with a nitinol structure produced for medical purposes were examined. If any metal decomposes in the body, it can endanger human life and can damage the body via heavy metal residues and toxic radical products that accumulate over long periods in the body. An in vitro degradation test was performed according to the standard 10993-13 and metal release values were found after short periods (one month) for nitinol. In the present study, the release values and possible toxic effects of nickel and titanium within the body with long-term intra-body use were examined. By calculating the mass loss caused by degradation, its relationship to heavy metal release inside the body and the possible side effects on human health of heavy metal residues were evaluated. Low metal ion release values of heavy metals resulting from degradation were determined by the ICP-OES device. Physical changes (diameter) in the surface of stent parts were also measured to compare and evaluate with the degradation rates.