An angioplasty is a procedure performed to improve blood flow in the body’s arteries and veins. In an angioplasty procedure, imaging techniques are used to guide a balloon tipped catheter (a very thin tube) into an artery or a vein and advance it to where the vessel is blocked or narrowed. The balloon is then inflated, to open the affected blood vessel, deflated and withdrawn. Angioplasty procedures are also called «Percutaneous transluminal coronary angioplasty (PTCA) ». During angioplasty, a smallwire mesh tube called stent can be placed permanently in the newly opened artery or vein to help keep it open. In most cases, patients are discharged 24 to 48 hours after stent placement.
How does the procedure work?
The catheter is introduced typically through an artery of the leg, the arm or the wrist. Patients will not feel any pain during the procedure. Doctors use a video monitor (similar to aTV screen) to see the process. When the catheter reaches the narrowed vessel, an innocuous dye is injected (a contrast media) and doctors obtain an image of the coronary arteries (also called «coronary angiogram»). The angiogram makes it possible to see the size and location of the obstruction.
Once doctors know the exact location of the obstruction, they introduce what is calleda «guide wire» through the same access vessel and advance it to the obstruction.The balloon tipped catheter is then advanced over the wire to the obstruction spot, where the balloon is inflated. The inflated balloon compresses the plaque that is blocking the artery against the arterial walls and is then deflated. Doctors can inflate and deflate the balloon several times. Finally, catheter, guide wire and deflated balloon are withdrawn.
If doctors wish to place a stent in the artery, it is introduced with the catheter, on the balloon at the tip. When the catheter reaches the narrowed spot, the balloon is inflated and the stent expands open. Once the stent is open, the balloon is deflated and catheter, guide wire and deflated balloon are removed, leaving the stent in place to keep the artery open.
At the end of the procedure, a firm pressure will be applied to stop any bleeding. The opening in the skin is then covered with a dressing.
The procedure usually takes around an hour and a half and most of patients must stay hospitalized overnight. Patients may feel sleepy until sedation effect disappears. Nurses will monitor heart rate and blood pressure through the night.
What happens after the procedure?
After discharge, patients must drink plenty of fluids, and avoid driving, bathing or smoking for one or two days. Patients should also avoid standing or walking for a long time for at least the next following days. If a stent was inserted, patient must avoid strenuous exercise for 30 days.
After any angioplasty procedure, with or without stent placement, patients must take aspirin everyday for the rest of their lives. When a stent is placed, patients must take a blood thinner or an anti-clotting medication at least for a year. Doctors will prescribe dose and administration.
35 to 40% of patients undergoing a balloon angioplasty are expected to suffer additional obstructions in the treated area. This is called restenosis. Restenosis normally occurs within the following six months to a balloon angioplasty intervention. Arteries that have a stent can also close back again. Restenosis is common in 20 percent of patients with stents. In case of restenosis, another balloon angioplasty procedure or stent placement is usually indicated.
What kinds of stents are there?
- Conventional stents normally made of steel or cobalt chromium.
- Drug coated or drug eluting stents.
They provide the same structural support as conventional stents, but additionally, they are thought to slowly release the exact dose of drugs and, therefore, contribute to the prevention of restenosis (the reclosure of the artery as a result of the scarring process). Released drugs act limiting the excessive growth of tissue in the artery.
Can restenosis be prevented?
Doctors insist on finding new ways to prevent reclosure of arteries after an angioplasty or a stent placement. Doctors have been recently using new types of stents. Some of them are coated with drugs that reduce the chance of reclosure. These coated stents slowly release drugs to the surrounding tissue, which in turn slows down reclosure process or simply prevents it. In the long term, coated stents hold a promising solution to this process.
Researchers have also been working on the design of smaller or customized stents to be introduced in smaller blood vessels. They have also designed stents for vessels with many obstructions, even blood vessels thatbranch. Other stents are coated with anti-clotting drugs, which reduce the chances of reclogging in arteries. More recently, researchers have started to develop non metallic stents that will dissolve in the artery over time. These stents open arteries and bring the same benefits than conventional metallic stents, but reduce restenosis risk by disappearing from the artery.
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