Drug-eluting stents (DES) are a type of stent that are coated with a medication that is slowly released over time to prevent the re-narrowing of the artery (restenosis) after the stent is placed. The mechanism of action of DES is based on the delivery of the medication directly to the site of the stent placement, allowing for a higher concentration of the medication at the site of injury.
The most common drug used in DES is called sirolimus, also known as rapamycin, which is an immunosuppressant drug. Sirolimus works by inhibiting the activity of a protein called mTOR, which plays a role in the growth and proliferation of smooth muscle cells. By inhibiting mTOR, sirolimus reduces the growth of smooth muscle cells in the area of the stent, which helps to prevent restenosis.
Other drugs used in DES include paclitaxel, which is a chemotherapy drug that works by inhibiting the growth of cells, and everolimus, which is a derivative of sirolimus that also works by inhibiting the activity of mTOR.
The drug-eluting stents have been shown to be effective in preventing restenosis, however, there were concerns about the safety of these stents as they were associated with an increased risk of blood clots (stent thrombosis) which can lead to myocardial infarction and death. Therefore, the use of these stents is restricted to a specific patient populations who are at high risk of restenosis like diabetics, patients with small vessel disease, and patients who have a long lesion.
In conclusion, drug-eluting stents work by delivering medication directly to the site of the stent placement, which helps to prevent the re-narrowing of the artery after the stent is placed by inhibiting the growth of smooth muscle cells. Despite their benefits, the use of these stents should be restricted to specific patient populations and under the guidance of a physician. Dr. A. Arrazaghi. MD,FRCPC