Cardiac catheterization is a method doctors use to perform many tests and procedures for diagnosing and treating coronary artery disease. The method involves threading a long, thin tube (called a catheter) through an artery or vein in the leg or arm and into the heart. Depending on what your doctor wants done, different things may happen during cardiac catheterization. For example, you may have angioplasty, which uses a balloon on the end of the catheter to open narrowed arteries in the heart. You may also have a stent placed at the time of angioplasty. A stent is a small, mesh-like device made of metal that acts as a support, or scaffold, inside of a vessel.
During these procedures, doctors can gain access to the heart’s arteries by placing the catheter in the femoral artery and threading it up and into the heart. The femoral artery is a major artery in your groin area. Even though this is the traditional method, femoral artery access can cause many problems, such as bleeding at the puncture site and nerve damage. Also, after their procedure, patients need to lie very still for at least 5 hours to make sure that the puncture site in the femoral artery does not start to bleed again.
But the femoral artery is not the only route that can be used to reach the heart. Doctors can also use the radial artery, which is an artery in your wrist. Because the radial artery in the wrist is smaller than the femoral artery in the groin, it much easier to apply direct pressure to the puncture site to stop the bleeding. For most patients, radial access does not cause as much discomfort as femoral access does. Also, radial artery access allows many patients to get out of bed and walk around right after their procedure.
What is radial artery access?
If interventional cardiologists are going to perform your procedure through radial artery access, it means that they will use the radial artery in the wrist as the entry point for the catheter. The cardiologist threads the thin catheter through the body’s network of arteries in the arm and into the chest, eventually reaching the heart. Doctors may also call this transradial access, the transradial approach, or transradial angioplasty.
Which patients can have radial artery access?
Unfortunately, not all patients can have their procedure done through radial artery access. To be a candidate, patients must have good blood supply to their hands, through both the radial artery and the ulnar artery. The blood supply from both arteries has to be good in the rare case that the radial artery becomes blocked (occluded) after the procedure. If the blood flow through both arteries is good, then it would not matter if the radial artery becomes blocked, because the ulnar artery can take over entirely and supply enough blood to the whole hand.
Doctors determine if the blood supply to the hands is good by performing the Allen test. In the Allen test, your doctor presses his or her thumb against the ulnar artery, which is located in the “pinkie finger” side of the wrist. Your doctor will then press his or her other thumb on the radial artery, which is located on the thumb side of the wrist. You will be asked to open and close your hand until it turns pale. Then, your doctor will release the pressure over the ulnar artery. If a normal color returns to your hand in 8 seconds or less, your doctor knows that the ulnar artery can supply all of the blood that your hand needs in the rare event that your radial artery occludes.
This approach also cannot be done in patients who are very thin or who have small or twisted arteries.
What should I expect?
Patients are usually told not to eat or drink anything after midnight the night before the procedure. If you have diabetes, you should talk to your doctor about your food and insulin intake, because not eating can affect your blood sugar levels.
Talk to your doctor about any medicines (prescription, over-the-counter, or supplements) that you are taking. This is especially important if you are taking blood-thinning medicines or anti-platelet medicines. You will most likely have blood tests, an electrocardiogram, and a chest x-ray taken before the procedure.
Once you are in the cath lab, you will see television monitors, heart monitors, and blood pressure machines. You will lie on an examination table, which is usually near an x-ray camera. Small metal disks called electrodes will be placed on your chest. These electrodes hook up to an electrocardiogram machine which monitors your heart rhythm during the procedure.
You will be given an anesthetic medicine with a needle to numb the area around the wrist. You may feel mild discomfort. Then, a small incision will be made in the skin. Once doctors see the radial artery, a special needle is used to poke into it. Doctors then put the catheter into the radial artery. You should not feel pain during this part of the test.The catheter is then gently threaded through the radial artery and into your heart.
After the procedure is finished, the catheter and IV will be removed. Firm pressure will be applied to the radial artery to stop any bleeding. You will also be bandaged.
If you are not too heavily sedated, you may actually be able to walk out of the cath lab. Patients whose procedures have been done through femoral access cannot do this! You may feel a little sleepy until the sedative has worn off. Nurses will watch you to see that your heart rate and blood pressure are normal. After a short time of rest, you will be able to go home.
