Cardiac catheterization involves passing a thin flexible tube called a catheter through an artery or vein, to the heart, and into a coronary artery. This procedure produces angiograms (X-ray images) of the coronary arteries and the left ventricle, the heart's main pumping chamber. Catheterization can also be used to measure pressure in the pulmonary artery and to monitor heart function in critically ill patients.
In most cases, cardiac catheterization is recommended when a partial or complete blockage is suspected in an artery. It is used obtain information about the blockage and to evaluate how well the heart is functioning.
Cardiac catheterization is performed in our cardiac cath lab. Usually, the procedure takes two to three hours to perform. Patients must remain immobile for four to six hours following the procedure.
Your physician may request cardiac catheterization for the following conditions:
- Angina (chest pain) that is not easily controlled with medication, disrupts your daily routine, occurs at rest, or recurs after heart attack
- Heart failure with suspected coronary artery disease
- Heart valve disease with symptoms such as shortness of breath
- Markedly abnormal stress test results
- Recurring chest pain with no identified cause
Not everyone with angina needs cardiac catheterization. People who have very rare or easily controlled episodes of angina probably do not need to undergo the procedure. Many people who have suffered a heart attack can initially undergo a stress test rather than cardiac catheterization.
Coronary Angiography and Angioplasty
If you are experiencing chest pain or have risk factors for heart disease, your physician may recommend a test called an angiogram. A special dye is injected into your coronary vessels to make them show up well on an X-ray. Doctors can then look at the X-ray and determine why you are having problems.
If the angiogram shows that the vessels around your heart are narrow or blocked due to plaque build-up, your physician may suggest angioplasty to treat the problem. With this procedure, a catheter is used to create a bigger opening in the vessel to increase blood flow. Percutaneous Transluminal Coronary Angioplasty (PTCA) refers to angioplasty in the coronary arteries to permit more blood flow into the heart. There are several types of PTCA procedures, including:
- Balloon angioplasty - a small balloon is inflated inside the blocked artery to open the blocked area.
- Atherectomy - the blocked area inside the artery is "shaved" away by a tiny device on the end of a catheter.
- Laser angioplasty - a laser is used to "vaporize" the blockage in the artery.
- Coronary artery stent - a tiny coil is expanded inside the blocked artery to open the blocked area and is left in place to keep the artery open.
Both angiography and angioplasty can be performed with a general anesthesia in our cardiac catheterization lab. They generally do not require a hospital stay.
Drug Eluting Stent Placement
Stents are small metal devices that are similar in size and shape to the spring found in a ballpoint pen. They are implanted in blocked arteries to hold the artery open and allow adequate blood flow.
Before stent implantation, the blocked artery is usually treated and dilated with one or more angioplasty balloons. A stent, mounted on a special angioplasty balloon, is then guided to the site of the blockage. The angioplasty balloon is inflated to stretch open the stent and implant it into the walls of the blocked artery. The balloon is deflated and removed, and the stent remains permanently in place to hold the artery open.
Sometimes referred to as a "coated" or "medicated" stent, a drug-eluting stent is a normal metal stent that has been coated with a drug that will help prevent restenosis (re-blocking of the artery). Based on data gathered so far, the drug-eluting stent has been extremely successful in reducing restenosis rates from 20 to 30 percent down to single digits. There are many components that must go into the decision to place a drug-eluting stent. This type of stent is not appropriate in every artery. Your cardiologist will help you determine whether a drug-eluting stent is right for you.
Once a drug-eluting stent is placed, you will be required to take aspirin and an anti-clotting drug, such as clopidogril or ticlopidine (brand names Plavix and Ticlid) for up to six months after the stenting. This prevents blood from reacting to the new device by thickening and clogging up the newly expanded artery. Ideally, a smooth, thin layer of endothelial cells (the inner lining of the blood vessel) grows over the stent during this period and the device is incorporated into the artery, reducing the tendency for clotting.