Monday, January 29, 2018

Therapeutic cardiac catheterization with congenital heart defect




Valvuloplasty or balloon valvotomy:

This procedure is done to open a narrowed heart valve. Any of the heart's four valves can be narrowed. However, this procedure is most often used to open the valves connecting the heart to the lungs (pulmonary valve) or to the body (aortic valve). These narrowing occur bacause the valve leaflets don't open up completely. This makes it harder for the heart to pump blood to the lungs or to the body, The narrower the valve, the more pressure it takes to pump the blood through it.  To open the narrowed valve, a special catheter with a balloon attached to its end is used.
A picture of the valve is first taken and the size of the valve is measured carefully to select the correct-size balloon. If the ballon to small, the opening still not be big enough. If the ballon is to large, the valve may be damaged or the vessel may be torn. The balloon is inflated for only a few seconds, then it is deflated and removed.

Angioplasty:

This procedure widens a narrowed blood vessel. These narrowings are often associated with various congenital heart defects and can occur naturally or after surgery, Similar to a narrowed valved, a narrowed vessel restrict blood flow and causes the heart to work harder. Blood vessels that can be narrowed include:
  • The branch pulmonary artery
  • The aorta
  • Systemic veins
  • Pulmonary veins
Stent Implantation:

Sometimes, simply widening a narrowed blood vessel with balloon isn't effective. The narrowing in the vessel may be too long or it might strech out with the balloon but shrink again once the balloon is removed.

In this situation, a stent is used to provide structural support within the narrowed vessel to keep it wide open. Stent are metal mesh tubes. They are designed to strech open inside a narrowed blood vessel and hold the vessel wall open.

There are many types of stent, but the most common ones used in children are "balloon -expandable" stents. These are mounted onto a balloon and positioned at the site of narrowing through a long sheath. Then the balloon is inflated to expand the stent against the narrowed  vessel wall. The stent is opened to the appropriate size depending on the patient's size. The balloon is deflated and removed while the stent stays in the vessel to keep it from  renarrowing.

Balloon and blade septostomy:

In some special circumstances, it's necessary to create a larger hole between the walls of the heart's upper chambers (the right and left atrium). Special balloons and blade catheters are used to create  these openings to increase blood flow between the heart's upper chambers. This procedure can be performed in the cath lab or by the bedside in the intensive care unit under ultrasound guidance.

Valve perforation:

Some patients are born with a completely blocked pulmonary valve. This is called pulmonary atresia. When this occurs and blockage is due to a thin membrane of the valve, the blocked valved can be opened in the cardiac cath lab using radiofrequency perforation. This technique uses a special catheter that can generate heat to create a small opening in the blocked valve. Then the catheter can be placed across the valve and the opening enlarged using the same technique as described in the valvuloplastysection. When the blockage is due to a thickened abnormal valve, it may not be feasible to make an opening and surgery might be needed.

Occlusion procedure:
These procedure are used to plug up (or close) an unwanted opening or connection in the heart or in blood vessels. These heart defects can be closed using a variety of devices.

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