Angioplasty is a procedure to reconstruct or repair a blood vessel. In most cases, this term refers to a procedure to open and restore blood flow through a clogged artery. This procedure is a less invasive alternative to repair or replacement of the blood vessel.
Over time, cholesterol and other fatty substances in the bloodstream can form deposits on the inside of the artery walls. This disease process is known as atherosclerosis. When arteries become severely blocked, blood flow is diminished, causing damage to the organs served by those arteries. Heart attack and stroke are examples of the consequences of clogged arteries.
To prevent organ damage, an individual with severe artery blockage often needs a procedure to restore blood flow. One option is for the surgeon to construct an alternate route around the blockage using an artificial vessel or one harvested from elsewhere in the body. Coronary artery bypass surgery is one example of this approach.
Angioplasty is the other option. Because it is usually less risky and requires less healing time, it is preferred over bypass surgery if it is feasible. The surgeon will decide if a person is a candidate for angioplasty based on factors such as his or her general health and the location and severity of the blockage.
Angioplasty is sometimes performed as an emergency, immediately following a heart attack. In other cases, the procedure is done as a scheduled procedure when a person has symptoms of artery blockage, such as occasional chest pain, without current tissue damage. Angioplasty can also be performed when a blockage is seen during a cardiac catheterization. The technique is generally the same whether the procedure is done routinely or as an emergency.
Angioplasty may be performed on the arteries of the heart, neck, kidneys, or legs. The same general procedure is used although it may vary slightly from location to location. A thin tube called a catheter is used to perform the angioplasty. At the end of the catheter is a tiny, inflatable balloon.
The catheter is inserted through the skin into an artery, usually in the groin area. Before the catheter is inserted, the skin over the artery is cleaned and the hair in the area is shaved. Next, a local "numbing" medication is injected under the skin to provide local anesthesia. The person may also be given a mild sedative to relax.
A small skin incision is then made at the site. The tube is passed over a wire, which is used to guide it, and into the artery. The part of the tube that contains the inflatable balloon is positioned at the point of the blockage. In order to know exactly where to position the balloon, an x-ray test is performed to position the catheter and balloon, as well as to "map" the affected arteries.
These x-rays are taken in "real time," meaning, that instead of taking one picture, multiple images are obtained one after the other. This helps the surgeon position the wire, the tube, and the balloon, and look at the areas of blockage in the arteries. This procedure involves squirting a contrast agent into the artery. The contrast agent outlines the artery so that the contours show up when x-ray images are taken. In this way, the surgeon can see the blockage.
When the x-ray confirms that the balloon is in the right position, it is inflated and expands inside the clogged artery. The expanding balloon forces the blockage to open by pushing the walls of the artery outward. If the procedure is successful, the artery then remains open because the walls are stretched and some of the deposits on the walls are broken up. This restores blood flow through the artery.
Very often, a wire mesh tube called a stent is then placed inside the artery to help keep it open. If another blockage forms in the artery, a drug-coated stent may be placed in the artery to keep it from becoming blocked again. Brachytherapy, which involves placing radioactive material in the artery, may also help to keep an artery open.
A set of x-rays is taken after the procedure to ensure that the artery has been successfully opened. If these images confirm that the angioplasty restored blood flow, the procedure is over. If not, the process can be repeated. In some cases, the angioplasty may not be successful and the procedure is stopped. If this occurs, other treatment options must be considered, such as heart bypass surgery. In either case, the tube is removed and the skin incision is bandaged.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.