Cardiac catheterization
Cardiac catheterization is a specialized procedure in which a long, flexible tube called a catheter is inserted into a vein and guided into the heart allowing a close look at the structures inside. It may also be performed for the following reasons:
- To obtain cardiac tissue samples for biopsy (removing tissue to help obtain a diagnosis)
- To obtain diagnostic information about the heart or its blood vessels
- To open the atrial septum (a divider between the atrium) in congenital heart problems that causes a child to become cyanotic (blue color of the skin, lips, and nail beds due to an insufficient supply of oxygen in the blood)
- To place mesh devices that close small holes inside the heart or intentionally block blood flow in a damaged blood vessel
- To place wire devices, called stents, in narrowed arteries to keep them open
- To determine blood pressure in the heart's chambers, collect blood samples from the heart, or examine the arteries of the heart
Cardiac catheterization can be performed on children of any age; even newborns immediately after birth.
How is a cardiac catheterization performed?
The procedure is performed in the hospital by a specially trained cardiologist. A child is given a sedative to help her relax and possibly even sleep during the procedure. Once in the "cath lab," she lies on a small table with a C-shaped x-ray machine surrounding it and heart monitors nearby. A specially trained staff of nurses, technicians, and physicians monitor her and makes sure she is comfortable during the procedure. An injection of local anesthetic is given under the skin where the catheter is to be inserted. Next, a thin, flexible tube (catheter) is inserted into a blood vessel, most often in the groin area (the crease of the leg where it bends when sitting).
The catheter is guided up the vein towards the heart. The cardiologist uses x-rays to help visualize the movement of the catheter. The catheter enters the right atrium (the top right-hand chamber that receives oxygen-poor (blue) blood from the body). Eventually, the tube is guided into the right ventricle, the pulmonary artery and perhaps the right and/or left pulmonary artery branches.
While the catheter is inside the heart, several things are done to help evaluate the structure — as well as the pattern of blood flow — inside the heart. Blood samples are drawn and blood pressure measurements are taken from each chamber and blood vessel. Contrast dye is injected into the catheter and, as it flows inside the heart, x-ray films are made of the path the dye takes. X-ray films are made as the catheterization proceeds, enabling your child's cardiologist to review the data after the procedure. If surgery is planned, the heart surgeon may also review the data.
What happens after the procedure?
When the catheterization is complete, the catheter(s) will be withdrawn from the heart and the blood vessels. Several gauze pads and a large piece of medical tape will be placed on the site where the catheter was inserted to prevent bleeding. In some cases, a small, flat weight or sandbag may be used to help keep pressure on the catheterization site and decrease the chance of bleeding.
If blood vessels in the leg were used, your child will be told to keep the leg straight for a few hours after the procedure to minimize the chance of bleeding at the catheterization site. She is taken to a unit in the hospital where she is monitored by nursing staff for several hours after the test. The length of time it takes for your child to wake up after the procedure will depend on the type of medicine given to her for relaxation prior to the test, and on her reaction to the medication.
After the test, your child's nurse will monitor her pulses and skin temperature in the leg or arm that was used for the procedure. Your child may be able to go home after a specified period, providing she does not need further treatment or monitoring. You will receive written instructions regarding care of the catheterization site, bathing, activity restrictions, and any new medications she may need to take at home.
Depending on the results of the cardiac catheterization test, additional tests or procedures may be scheduled to gather further diagnostic information.
Congenital heart conditions that may be treated in the cath lab include:
- Patent ductus arteriosus (PDA), a condition in which certain blood vessels fail to close normally in an infant soon after birth. This leads to abnormal blood flow.
- Aortic stenosis (AS), a condition in which a narrowing of the aorta makes circulation of blood difficult
- Pulmonary atresia (PA), a condition in which the valve for the pulmonary artery does not function properly
- Re-coarctation (narrowing) of the aorta
- Atrial septal defect (ASD), a condition in which walls that separates the upper chambers (atria) of the heart do not close properly
- Ventricular septal defect (VSD), a condition in which the wall that separates the lower chambers of the heart (ventricles) does not close properly
- Branch pulmonary stenosis, a narrowing of the pulmonary artery
- Narrowing or re-stenosis of shunts. A shunt is a diversion of fluid from one area of the body to another.