| From your Guide Dr.MANI |  | |
Tricuspid Atresia | ||
| From your Guide Dr.MANI | | |
Tricuspid Atresia | ||
|
||||||||
How can Tricuspid Atresia be repaired ?
Although it may seem that placing an artificial valve between the right atrium and ventricle will solve
the problem, it is not possible. This is because, since there has been no tricuspid valve since birth,
the area where the valve should have been has not developed at all, and is very small. So alternate
methods to repair the condition had to be devised.
After several "false starts", Dr.Francis Fontan first made the revolutionary attempt to completely
"do away" with the right ventricle. He successfully created something which today is called a
"Fontan-type" circulation.
What is a Fontan-type circulation ?
Let me take some time to explain this, as it is an integral part of the entire operation for tricuspid
atresia.
We - you, me, cardiologists, surgeons, and everyone else - have been accustomed to thinking of
the heart as having four chambers - two atria and two ventricles. These four chambers acting in
unison maintain the circulation of blood.
To understand the Fontan circulation, you must make a "leap of imagination". In your mind,
eliminate the right ventricle from the heart ! Tough isn't it ? And how can the heart possibly work
without a right ventricle ?
Illogical as it may seem, this however was exactly what Dr.Fontan proved with his operation. In his
original repair, he connected the right atrium directly to the pulmonary artery, and closed the ASD.
Blood entering the right atrium from the veins passed across this surgical connection into the
pulmonary artery and to the lungs. It completely bypassed the right ventricle.
Wait a minute ! There must be a flaw in this somewhere. How can the blood enter the lungs if it is
not PUMPED IN by the right ventricle ? Well, that really is what makes this procedure unique -
and stands testimony to the genius of Dr.Fontan. Normally the right ventricle will do the pumping.
But in tricuspid atresia - and many other conditions in which a Fontan operation is performed -
there is NO right ventricle. So blood flows PASSIVELY into the lungs - without being propelled
into them by a right ventricle.
Why is lung blood flow so important ?
Because it is the only place in the body that blood can be purified by the addition of oxygen. So
when lung blood flow is very low, oxygen supply is reduced to the entire body. This has many
harmful effects, since no organ can perform its work normally without oxygen for energy.
So where does the energy for blood flow to the lungs come from ?
 |
 |
|
Copyright 1998, All rights reserved. |
