Cardiac catheterization is a specialized procedure in which a long, flexible tube (catheter) is inserted into a blood vessel (usually in the leg) and guided into the heart, allowing a close look at the structures inside. Cardiac catheterization may be recommended for diagnostic purposes, with the intent of obtaining information only. It can also be therapeutic, with the intent of providing treatment or intervention for an abnormality, such as a congenital (present at birth) heart problem.
It may be performed for the following reasons:
To obtain diagnostic information, such as pressures and oxygen levels in various parts of the heart
To further define heart anatomy in the setting of congenital heart problems
To obtain cardiac tissue samples for biopsy
To open the atrial septum in congenital heart problems that cause a child to become cyanotic (blue color of the skin, lips, and nailbeds due to an insufficient supply of oxygen in the blood)
To place mesh devices that close small holes inside the heart (such as with atrial septal defect or ventricular septal defect)
To intentionally block blood flow in a blood vessel (such as with patent ductus arteriosus or pulmonary collateral vessels)
To place wire devices, called stents, in narrowed arteries to keep them open
There may be other reasons why your doctor would recommend cardiac catheterization for your child.
Cardiac catheterization can be performed on children of any age--even newborns immediately after birth.
The procedure is performed in the hospital by a specially trained cardiologist. Your child's doctor will discuss the risks and benefits of the procedure with you and will then obtain written permission (informed consent) from you in order to perform the procedure.
Your child is given a sedative to help him or her relax and possibly even sleep during the procedure. Once in the "cath lab," he or she will lie on a small table with a c-shaped X-ray machine surrounding it. Heart monitors and other equipment are nearby. A specially trained staff of nurses, technicians, and doctors will monitor your child and make sure he or she is comfortable during the procedure.
An injection of local anesthetic will be given under the skin where the catheter is going 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 vessel (artery or vein depending on the purpose of the procedure) towards the heart. The cardiologist uses X-rays, called fluoroscopy, to help visualize the movement of the catheter. From the vein, the catheter enters the right atrium--the top right-hand chamber that receives oxygen-poor (blue) blood from the body. Eventually, the tube will be guided into the right ventricle, the pulmonary artery, and perhaps the right and/or left pulmonary artery branches. In addition, another catheter may be placed into the artery in the groin, which can be advanced to the aorta.
While inside the heart, several things are done to help evaluate the heart structures, as well as the pattern of blood flow inside the heart, including the following:
Blood samples are drawn from each chamber and each blood vessel, and the oxygen content is measured.
Blood pressure measurements are made inside each chamber and each blood vessel.
Contrast dye is injected into the catheter and, as it flows inside the heart, X-rays are used to show the path the dye takes throughout the heart.
X-ray movies (angiograms) 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 will also review the data.
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.
Your child will be taken to a unit in the hospital where he or she will be 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 your child for relaxation prior to the test, and also on your child's reaction to the medication.
After the test, your child's nurse will monitor the 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 of time, providing he or 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 your child 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.
Advances in interventional cardiac catheterization have changed the diagnostic workup for babies and children with newly suspected congenital heart disease greatly. As a result of improved diagnostic imaging with echocardiography and magnetic resonance imaging (MRI), fewer cardiac catheterizations are performed just to obtain anatomic information. Instead, catheterizations are often performed in order to intervene with or treat a known heart disorder.
Congenital heart conditions that may be treated in the cath lab include:
Patent ductus arteriosus (PDA)
Aortic stenosis (AS)
Pulmonary atresia (PA) with multiple collaterals
Coarctation of the aorta
Atrial septal defect (ASD)
Ventricular septal defect (VSD)
Pulmonary artery stenosis
Narrowing or re-stenosis of shunts
This is not an exhaustive list of congenital heart conditions that may be treated in the cath lab currently. Your child's doctor may advise an interventional cardiac cath procedure for a different condition. Development of additional interventional cardiac cath procedures to treat other conditions is continuing.
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