How does the test work?
Your provider uses a needle to place special equipment, including a catheter (which is a small specially shaped tube), into a blood vessel (artery or vein). This can be done in your arm, in the neck, or in your leg. Your provider then injects contrast material through the catheter and creates X-ray movies (coronary angiogram or coronary angiography) as the contrast material moves through your heart’s chambers, valves and major vessels. The digital photographs of the contrast material allow your provider to identify the site of the narrowing or blockage in the coronary artery, evaluate the size and shape of heart chambers and/or blood vessels and find abnormal leaks or holes.
Additional imaging procedures
In some cases, your healthcare provider may perform intravascular ultrasound (IVUS) and fractional flow reserve (FFR) along with cardiac catheterization to obtain more detailed images of your blood vessel walls. Only specialized hospitals and research centers have these imaging procedures.
- Intravascular ultrasound: Your provider positions a miniature ultrasound probe (transducer) on the tip of a coronary catheter. They thread the catheter through your coronary arteries and, using high-frequency sound waves, produce detailed images of the inside walls of the arteries. IVUS produces an accurate picture of the location and extent of plaque (fat and cholesterol buildup). It can also identify other problems in blood vessels, such as calcium buildup, and it can help providers make sure any stents they put in the artery are positioned correctly.
- Optical Coherence Tomography (OCT): This is another type of technology that can take pictures inside blood vessels. OCT uses a small laser instead of ultrasound. Depending on what type of imaging technology your provider is used to, and what problem they are looking for, they may choose either OCT or IVUS.
- Fractional flow reserve: Your provider threads a small wire into the artery which can measure the pressure on both sides of a blockage. This can be done with a medication that simulates a stress test. The wire helps identify whether a blockage is bad enough to require treatment.
How do I prepare for the test?
You’ll need to make your provider aware of any medicines you’re taking and any allergies you have. Your provider will let you know how long before your procedure you should stop eating and drinking. Usually, you’ll need to stop eating and drinking six to eight hours before your heart catheterization.
Discuss all of your allergies with your provider, especially these:
- IVP dye/contrast agent allergy.
- Iodine allergy.
- Latex/rubber products allergy.
Discuss your medications with your provider, who may want to stop or adjust the doses several days before or on the day of the procedure, especially these:
- Blood thinners (anticoagulants).
- Diabetes medications, especially metformin.
Ask your provider if you’ve completed or scheduled all of the required tests before your cardiac catheterization procedure. These may include some of the following:
What to bring
Wear comfortable, easy-to-fold clothing on the day of your procedure and bring:
- A family member with you to wait with you before the procedure.
- A robe to wear as you wait for the procedure.
- Toiletries and any other items you would like to make your stay more comfortable if you stay in the hospital after your procedure. Your family member can retrieve these items from your car when you need them. Leave all valuables at home or with a family member.
- A list of your medications (including over-the-counter drugs) and dosages. When you arrive for your appointment, tell your provider if you’re taking warfarin (Coumadin® or Jantoven®), clopidogrel, diuretics (water pill) or insulin. Also remind the staff if you’re allergic to anything, especially iodine, X-ray dye, penicillin-type medications, latex or rubber products (such as rubber gloves or balloons).
What to expect before the test
The cardiac catheterization room is cool and dimly lit. Your healthcare provider has to keep the air cool to prevent damage to the X-ray machinery they use during the procedure.
- You’ll change into a hospital gown and your provider will offer you warm blankets to make you more comfortable.
- Your provider will start an intravenous (IV) line in your arm so you can receive medications and fluids during the procedure.
- You’ll lie on a special table. If you look above you, you’ll see a large X-ray camera and several TV monitors. You can watch your cardiac cath on the monitors, but you must keep your head down so that you don’t bump into the camera accidentally.
- Your provider will clean (and possibly shave) your skin at the site (arm or groin) where they’ll insert the catheter (narrow plastic tube).
- Sterile drapes will cover the site and help prevent infection. It’s important that you keep your arms and hands down at your sides, under the sterile drapes.
- Your provider will place electrodes (small, flat, sticky patches) on your chest. The electrodes attach to an electrocardiograph monitor (ECG), which monitors your heart rate and rhythm.
- You’ll receive a mild sedative to relax you, but you’ll be awake and conscious during the entire procedure. For some cases which are very short, you may not receive a sedative, especially if your provider wants to take certain kinds of measurements such as pressure inside your heart chambers.
- In some cases, you may need a urinary catheter during the procedure.
What to expect during the test
Once you and your healthcare team are ready, your cardiac catheterization begins.
What to watch for during your procedure
During your procedure, tell your provider if you feel:
- An allergic reaction (itching, tightness in the throat, shortness of breath).
- Chest discomfort.
- Any other symptoms.
Cardiac catheterization procedure
- Your provider will inject a numbing medicine underneath your skin with a small needle. They’ll insert a plastic introducer sheath (a short, hollow tube through which they place the catheter) in a blood vessel in your arm, neck or groin. Then they’ll insert a catheter through the sheath and thread it to your heart’s arteries. You may feel pressure when your provider puts in the introducer sheath or catheter, but you shouldn’t feel pain. Tell your provider if you do.
- To help position the catheter, your provider may ask you to turn your head or take a deep breath and hold it for a few seconds.
- When the catheter is in place, your provider will dim the lights and inject a small amount of contrast material through the catheters into your arteries and heart chambers. The contrast material outlines the vessels, valves and chambers.
- When the contrast material goes into your heart, you may feel hot or flushed for several seconds. This is normal and will go away in a few seconds.
- Your provider will use an X-ray camera to take photographs of your arteries and heart chambers while the contrast is flowing through them. You may need to hold your breath while your provider takes the X-rays. When all the photos are done, your provider will remove the catheter and turn the lights on.
- The sheath has to be removed very carefully because pulling it out incorrectly can cause you to bleed. Your provider will ask you to keep as still as you can while they remove the sheath.
Interventional procedures (percutaneous coronary intervention or PCI)
With the ability to put other devices at the end of the catheter, your healthcare provider may combine an interventional procedure with your cardiac catheterization. An interventional procedure (also called angioplasty) is a nonsurgical treatment that opens narrowed coronary arteries to improve blood flow to the heart. Your provider can perform an interventional procedure during a diagnostic cardiac catheterization when they find a blockage, or they may schedule it after a catheterization confirms the presence of coronary artery disease (narrowing or blockage of your heart’s arteries). An angioplasty opens your coronary artery, increasing blood flow to your heart.
Interventional procedures include:
- Balloon angioplasty.
- Stent placement.
- Rotablation, a special procedure to treat calcium deposits in arteries.
- Intravascular lithotripsy, where a special balloon uses pressure waves to break up calcium.
What to expect after the test
Your healthcare provider will remove the catheters and sheath after your procedure.
If you had a catheter in your arm
- They’ll bandage your puncture site.
- You’ll need to keep your arm straight for at least an hour, but you’ll be able to walk around.
- They’ll observe you for a few hours to monitor any symptoms or side effects of the procedure.
- You’ll get instructions regarding how to care for your arm when you return home.
- Tell your provider if you think you’re bleeding (wet, warm sensation) or feel any numbness or tingling in your fingers.
If you had a catheter at your groin
- Your provider will close your puncture site with applied pressure, and sometimes a suture device or a “plug.” A plug is a material that works with your body’s natural healing processes to form a clot in your artery. This reduces the risk of bleeding.
- You’ll need to lie flat and keep your leg straight for two to six hours to prevent bleeding (less time if they used a plug). Don’t raise your head more than 30 degrees (two pillows high). Don’t try to sit or stand until your provider tells you it is safe to do so.
- They’ll place a sterile dressing on your groin area to protect it from infection. They’ll check your bandage regularly, but call your provider if you think you’re bleeding (have a wet, warm sensation) or if your toes begin to tingle or feel numb.
Cardiac catheterization recovery
- You’ll need to drink plenty of liquids to clear the contrast material from your body. You may feel the need to pee more frequently. This is normal. If you’re on bed rest, you’ll need to use a bedpan or urinal.
- Your provider will tell you if you’re able to return home or will need to stay overnight. In either case, they’ll monitor you for several hours after the procedure.
- Before you go home, they’ll talk with you about your treatment, including medications, diet and future procedures. They’ll also talk about caring for your wound site, activity and follow-up care.
A responsible driver must drive you home. Your provider won’t discharge you unless you have someone available to drive you home.
If you have more than a two-hour drive home, you should stay overnight in a hotel for your comfort. Some hospitals have a medical concierge to help you make arrangements. Then have your family member drive you home the next morning after you have rested.
During your drive home, stop every hour and walk for five to 10 minutes. If you’re traveling home by plane, stand up to stretch your legs and walk in the aisle at least every hour.
Ask your healthcare provider when you can resume driving and exercising.
What are the risks of this test?
People rarely have complications from heart catheterization. One million cardiac catheterizations take place in the U.S. each year, but the chances of a major complication during a heart catheterization for diagnostic reasons is less than 1%. Your cardiologist will discuss the specific risks and potential benefits of the procedure with you. Some of the possible cardiac catheterization risks include:
- Allergic reaction to the medication or contrast material you received during the procedure.
- Irregular heart rhythm.
- Low blood pressure.
- Bleeding at the catheter insertion site.
- A collapsed lung (pneumothorax).
- Continued chest pain or angina.
- Mild to moderate skin reactions (like a sunburn) from X-ray exposure.
- Kidney failure.
- Cardiac tamponade (fluid buildup around your heart).
- Heart attack, blood clots, stroke or death.
- Damage to a coronary artery.
- Emergency coronary artery bypass graft (CABG) surgery.
- Damage to blood vessels which may require emergency surgery.
There may be other possible risks. When you meet with your provider, ask questions to make sure you understand all of the potential risks and why they recommend the procedure.