A drug-eluting stent is a type of stent applied in the case of diseased or narrowed coronary arteries, gradually releasing a drug to block any cell proliferation that occurs due to the healing tissues around the stent. Usually restenosis occurs even after the artery is repaired, which is the renarrowing of the artery caused due to tissue overgrowth around the stent. The renarrowing again leads to constricted blood flow proving fatal unless countered. In this visual illustration, a bare-metal stent is inserted at first but the artery re-narrowing occurs. During the second trial, a drug-eluting stent is used which successfully prevents the re-narrowing.
What’s a stent?
A stent refers to an artificial tube placed into a conduit inside the human body in order to prevent or counteract a localized flow constriction. The coronary stent is delivered mounted on a balloon and can be opened once placed inside the artery via a catheter. Generally, the term can even be applied in the case of a tube holding open a natural conduit during the course of a surgery. Initially, coronary stents came with the risk of early thrombosis (clotting) which lead to the blockage of the stent-assisted artery. To counter this, a drug-therapy was introduced which did reduce the occurance of early stent thrombosis and it was relatively more successful than balloon angioplasty or other techniques. The vulnerability to restenosis, caused almost always by neointimal tissue growth, persisted.
This lead to the advent of drug-eluting stents, designed by developers so that the devices themselves can be used to deliver the medication directly to the arterial wall. Initial attempts appeared to be unsuccessful but in 2001 the developers successfully demonstrated how the release (elution) of drugs possessing certain properties, from the stent, can deliver a high concentration of the medication directly at the target region. In essence, drug-eluting stents are metal sheets inserted into natural conduits of the human body, which elute a drug designed to limit the growth of neointimal scar tissue over the stent. This largely helped in preventing the restenosis.
Why is drug-eluting stent better than bare-metal stent in most cases?
After clinical trials, drug-eluting stents proved to be far superior when compared to bare-metal sheet stents in the treatment of coronary artery narrowings. Bare-metal stent is composed of a mesh-like tube of thin wire and does not carry any medication to counteract the neointimal tissue growth causing blockage. Countless patients have been successfully treated with drug-eluting stents forfending the demand for more invasive procedures. Added to it is the reduced risk of re-narrowed arteries that in other case would have lead to repeat hospitalization and angioplasty procedures.
But current studies have shown that drug-eluting stents may cause late & sudden thrombosis if the anti-platelet therapy is discontinued. Therefore, in the case of big vessels and short lesions, bare metal stent is still preferred to a drug-eluting stent.
If you have a drug-eluting stent inserted in your artery
It is necessary for the intake of anti-clotting medications as directed by your physician. You should postpone any non-cardiac surgery that may have been scheduled for the same year after inserting the stent. Optimally you should wait for another year and in case the surgery cannot be postponed, then discuss with your physician about the medications you should be taking at that time. And if you won’t be able to take anti- clotting medication as per your physician’s direction, then a bare-metal stent or another treatment could be a better choice. Remember to always talk to your physician about your situtation.