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Bare-metal stent and drug-eluting stents
In 1977, Dr.A. Gruntzig performed the first PTCA. Since then, during last 29 years, angioplasty has been improved and became a leading treatment in cardiology. The improvements went from home-made balloon-catheters over laser and rotablators to industrial produced bare-metal stents and drug-eluting stents.
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In the early years, the lesion or the blockage was only being treated with a balloon. The rate of restenosis, which is a post-procedure re-narrowing or the artery, shifted between 30% and 50%. By the end of the eighties, the stent was being introduced into the hospital. The stent is a small wire-mesh, lattice-shaped, metal tube which is placed into the coronary artery. The ideal stent is radiopaque (visible through X-ray), minimally thrombogenic (prevent blood clotting), flexible for passage through the coronary arteries and need to have sufficient radial strength when deployed to maximize the diameter of the inner lumen. Since the development of the stent, the medical world still faced restenosis. The rate of restenosis still shifted between 10% and 30%. As a stent is not human material, the body will react with covering the stent with a new inner-lumen of the vessel. This covering can become too thick and may develop a new in-stent stenosis or a new blockage. The latest improvements are the drug-eluting stents, with a restenosis rate of 0 – 5%. Drug-eluting stents are stents that elute a small amount of medication during a period of time, after the placement of the stent. The medication slows down the growth of cells on the inner-lumen of the artery. |
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The procedure The main procedure of placing a stent is similar to the PTCA. Depending on the chosen entry site, the groin, arm or wrist is being injected with a local anaesthetic. A sheat is being placed into the artery by the Seldinger-technique. Through the sheat a guide-wire (a very small, non-traumatic and radiopaque wire) is being brought to the aortic valve. A guiding catheter is being brought to the ostium, or the entry place of the coronary artery right above the aortic valve. The correct place is being checked with a small amount of contrast-agent. Through the guiding catheter and over a special designed PTCA-guide-wire, a small catheter with a balloon and a stent is guided towards the lesion. Under radio-fluoroscopy the stent is being put in place. After the balloon is expanded, the stent is placed in the lesion. The balloon will be deflated, but stays in place until the position of the stent has been checked with a small amount of dye. If necessary, the balloon is expanded again. When, after control, the stent is fully unfolded, the balloon catheter is being withdrawn, together all the other materials. The puncture place is closed adequately. |
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After the procedure
When the femoral artery is been used to access the coronary artery, the patient is advised to stay in bed for a few hours. Procedures, in which the radial artery has been used for access, permit immediate sheath removal and allow early mobilisation. Although in both cases the patient is being referred to a recovery-ward or coronary care unit for close monitoring of ischaemic signs and haemodynamic stability.
The cardiologist will prescribe the patient anti-platelet therapy.
