Medicated (Drug-Coated) Stents
Stents decrease the abrupt blockage frequently occurring after treatment of the problematic area with only a balloon. However , again after the first 6 months following the implantation, re-narrowing might occur in the same problematic area in some cases and make re-intervention a necessity. In recent years, new stent types (medicated or drug-coated stents) have been developed. These stents, with their polymer coating engrained with a special medicine inside (sirolimus, paclitaxel etc.), reduce or prevent the re-narrowing in the stent implanted areas by thwarting cell reproduction.
Coronary balloon angioplasty and stent procedures have revolutionized the treatment of heart and artery diseases. Before these procedures had been developed, patients with a significant narrowing in their heart vessels were either operated on using by-pass surgery or if the patient’s condition was not suitable for surgery, they would have been treated with medication. As treating this disease with a drug does not stop or reverse the existing narrowing, the complaints of patients continued at a high rate. Therefore, the development of balloon and stent procedures have been a breakthrough in the treatment of heart and artery diseases and have reduced the number of patients operated on significantly. Consequently, these methods have kept patients away from the negative effects of surgery.
The method for treating heart diseases with a balloon was carried out on humans for the first time in 1977. The patients treated with balloons frequently experienced high rates of abrupt blockage and re-narrowing and patients in this condition were mostly treated using by-pass surgery. The drug-coated stents were developed to overcome the high rates of abrupt blockage and re-narrowing problems arising after the treatment with a balloon. They indeed overcame this problem to a large extent.
In these cases bare metal stents are not sufficient and drug-coated stents are currently utilized. In the studies performed, it is observed that the narrowing was significantly lower in the vessels treated with drug-coated stents (5-10%). Lower narrowing rates create a big advantage for the patients as intervention or surgery may not be necessary after the operation.
The results of the studies conducted on drug-coated stents are far better in cases where the possibility of re-narrowing or having a problem after the operation is higher. For this reason, in these kinds of cases doctors prefer using drug-coated stents.
Nevertheless, clotting and blockage may occur despite the advantages of the drug coated stents. Although the drug released from the stent delays the endothelialization (the narrowing rate decreases), the surface of the stent contacts with the blood for a longer time and even months after the implantation and blockage with sudden clots may appear.
Therefore, aspirin usage after the implantation of a drug-coated stents would be longer compared to the bare metal stents (9 months or even longer).
Today, studies to overcome this problem are still being carried out. Stents with drug-loaded dissolving polymers are currently aimed to eliminate these problems and some do eliminate these problems to a large extent.
The drug in the polymer goes away after being released for a certain period of time and due to the dissolution of the polymers, which carry the drug, the requirement of medication usage for a long-term period becomes unnecessary. Following this , the hemophilic case, which is temporarily caused by the drugs used, disappears and the patient may undergo other operations - albeit the use of drug-coated stents - and risks in this respect would disappear accordingly.
With these types of drug coated stents which have been developed recently and possess dissolvable polymers, the problems inside the vessels can be treated and the disadvantages of the previously developed drug-coated stents are not confronted.
Please consult with your doctor for further information on the entirely dissolving polymer-coated stents and on all other drug-coated stents.