PALLIATION FOR TETRALOGY OF FALLOT

When is an Intra-Cardiac Repair not feasible for ToF ?

There are many such situations.
If, for instance, the pulmonary artery branches are NOT AT ALL developed (Pulmonary Atresia), a one-stage total correction operation is impossible. For then, where would blood from the right ventricle go ?
Somewhat similar is the condition where the outflow tract of the right ventricle is VERY narrow at any portion - at the valve, or above it, or in one of the branches. Here, even with repair and widening of the narrowed area, significant block to blood flow will persist. If a one-stage operation is performed, then all the blood from the right ventricle would be FORCED to travel through the repaired, yet narrow outflow tract.

What happens then ?

The right ventricle has to work harder to pump blood through a narrow passage - it is like packing all your clothes into a very small suitcase, you have to push harder to get it all in ! And the right ventricle cannot do this forever. It gets tired, and "fails". If a palliative operation is done first, this problem can be avoided.
Then again, there are some babies who are too small. They would not be able to tolerate a difficult operation. Or there may be many other coexisting birth defects (multiple VSDs,abnormal coronary arteries). The presence of such defects would greatly increase the risk of a direct repair.

What are the palliative operations for ToF ?

The significant problem in ToF is REDUCED blood flow into the lungs. This results in reduced oxygen delivery to the body.
The operations designed to increase blood flow into the lungs are called Systemic-Pulmonary Shunts. These are connections between the aorta or one of its branches (the "systemic" arteries) and the pulmonary artery. The principle underlying these shunts is that a portion of blood flow from the arteries will be directed across the shunt into the pulmonary artery and its branches. This has two effects.

• First, by increasing the total lung blood flow, the amount of oxygen available for distribution to the rest of the body is increased.
• Second, the increasing amount of blood flowing into the pulmonary artery and its branches stimulates them to grow in size. The narrow portions may become wider. So, later, when an operation for total correction is performed, there is little or no obstruction to lung blood flow.

What are the types of systemic - pulmonary shunts ? Find out .....

 

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