Different types of stent

• two main types of stent are currently in use:
  • bare-metal stents (BMS), which are usually constructed of stainless steel
  • drugeluting stents (DES), in which the metal struts have been coated with a growth inhibiting agent that elutes from the device in minute quantities
    • by inhibiting smooth muscle cell proliferation the eluted drug reduces the volume of neo-intimal tissue and, consequently, reduces the frequency of restenosis (by a factor of about 50 percent)
      • however, it also inhibits endothelial cell proliferation, thereby slowing the process of re-endothlialisation
        • thus DES expose the patient to a longer period of, and in some cases indefinite, risk from thrombosis
      • the DES implanted most extensively in the United Kingdom utilise paclitaxel, an anti-cancer agent or rapamycin, an immunosuppressant used in transplant medicine.Whilst DES are more effective than BMS at preventing restenosis and the need for a repeat procedure, their associated treatment costs are higher and neither has been shown to be superior in terms of long term cardiovascular outcome

Reference:

• (1) British Heart Foundation Factfile (May 2008). Managing patients with coronary stents.