Drug eluting stents: Drug eluting stents (DES) are tiny spring like structures used to scaffold a blood vessel after angioplasty (removal of blocks), having a coating with medications which prevent ingrowth of cells into them. They are also called medicated stents. They are better than bare metal stents in maintaining patency of the blood vessel on the long term.
What type of medications are used in drug eluting stents?
Medications used to coat drug eluting stents are those which inhibit the rapid multiplication of cells. Actually they belong to the family of anti-cancer drugs, which also prevent rapid multiplication of cells. But unlike anti-cancer drugs which are injected in larger quantities into the circulation, in drug eluting stents, only a tiny amount is present locally. They prevent ingrowth of cells into the blood vessels which would otherwise occur and cause rapid re-blocking of blood vessels opened by angioplasty.
Are there any disadvantages for drug eluting stents compared to bare metal in special situations?
Generally drug eluting stents are superior to bare metal stents so much that bare metal stents are seldom implanted these days. This is more so with newer generation DES which have overcome most of the shortcomings of the older generation DES. One disadvantage of older DES was the high risk of clot formation within them if blood thinners (anti-platelet agents) had to be stopped for some reasons. The risk was higher if the medications had to be stopped early after implantation of DES.
Hence it was a practice to implant a bare metal stent if the need for early stoppage of anti-platelet medication was anticipated. For example, if the person needs a semi-urgent major surgery (non cardiac), but had significant blocks in the blood vessels of the heart with chest pain, he would be given a bare metal stent after angioplasty. But with newer generation DES, the waiting period for an elective noncardiac surgery is lesser compared to older generation stents for which it would reach up to 1 year for non urgent situations.
Actually a balance has to be stricken between the risk of recurrence of block in the blood vessels of the heart and the urgency of the planned non cardiac procedure. But in any case some amount of risk is always involved in this decision. and it is always a shared decision making between the patient/relatives and the treating team.