Surface Morphology and Histopathological Aspects of Metallic Used Cardiovascular CoCr Stents

Abstract

In this study, CoCr cardiovascular metallic stents with the same chemical composition as well as the adjacent tissues were analyzed. Recovered stents and adjacent tissues were characterized by surface morphology techniques like light microscopy (LM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The presence of metals in the tissue from around explanted stent was also confirmed by TEM method. The released metal ions were measured using inductively coupled plasma mass spectrometry (ICP-MS). Histopathological analysis was used to highlight host tissue response to the implanted stents. EDX analysis revealed that 21 stents had the same composition. The quantities of Cr ions detected in the tissues were between 5 and 14 ppb and for Co ions were between 4 and 10 ppb. The tissue sections near the layers that generated large quantities of ions showed restenosis development and the deposits of surface calcifications were highlighted. The heavy metal levels observed in this study due to corrosion are too low to cause a systemic toxic response.