What happens when the Pulmonary Valve is not there ?
When the pulmonary valve is not there, there is a membrane of a “wall” which does not allow communication between the heart and the tube taking blood to the lungs.
How does the baby survive then?
First, the baby does not need blood going to the lungs when the baby is not yet born (the child does not breathe in utero). So, this problem does not show itself up till the baby is born. Even when the baby is born, the child’s lung blood flow is maintained by a Patent Ductus Arteriosus (PDA), which is a tube allowing blood flow from the aorta to the pulmonary artery (from the tube carrying blood into the whole body (pink blood) to the tube carrying blood to lungs).
What happens to the PDA?
The PDA usually tends to close anytime in the first few days to a week after birth. When that happens, blood cannot reach the lungs to get more oxygen, the fuel for the body. So, the baby turns blue and unless improvement is ensured in a few hours, the child is not going to survive! If detected or suspected, the PDA can be kept open by an intravenous medicine, Prostaglandin!
What after the Prostaglandin ?
After Prostaglandin has been started, this medicine cannot be continued for too long; it is not the destination therapy; it is the bridge to final therapy. The final therapy in this situation is a Shunt Operation.
What is a “shunt” ?
A shunt is an operation where in a tube (artificial material) is inserted between the pulmonary artery and the aorta or one of its branches. This is done surgically. The tube provides a secure blood flow into the lungs like a PDA temporarily provides.
What happens in the future?
As the baby grows, the shunt does not and the amount of blood the shunt is able to carry decreases for the weight of the child. This results in the child getting blue as the child grows. At that stage, the child needs to have complete repair done.
What is a good age for the complete repair to be done?
Since the repair involves insertion of a valve in the heart, and the valve is not going to grow, it would need to be replaced again. In the developing world, it is prudent to accept that complete repair be done when an adult size valve can be inserted. This would decrease the number of surgeries for the child. So, the repair is done around 4-5 yrs age. The repair involves closure of the hole, placement of the valve ad a tube which connects this valve to the lungs.
Are there any long term problems with the Valve and Conduit inserted in the child with Pulmonary Atresia ?
The conduit (tube) can narrow down; the valve can become leaky; the vale can narrow down too. Basically they can shrink and if they do, the child would need to have ballooning or stent placement or even replacement of the tube done.